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毕业设计中英文翻译【范本模板】

毕业设计中英文翻译【范本模板】

英文The road (highway)The road is one kind of linear construction used for travel。

It is made of the roadbed,the road surface, the bridge, the culvert and the tunnel. In addition, it also has the crossing of lines, the protective project and the traffic engineering and the route facility。

The roadbed is the base of road surface, road shoulder,side slope, side ditch foundations. It is stone material structure, which is designed according to route's plane position .The roadbed, as the base of travel, must guarantee that it has the enough intensity and the stability that can prevent the water and other natural disaster from corroding.The road surface is the surface of road. It is single or complex structure built with mixture。

The road surface require being smooth,having enough intensity,good stability and anti—slippery function. The quality of road surface directly affects the safe, comfort and the traffic。

毕业论文(设计)外文文献翻译及原文

毕业论文(设计)外文文献翻译及原文

金融体制、融资约束与投资——来自OECD的实证分析R.SemenovDepartment of Economics,University of Nijmegen,Nijmegen(荷兰内梅亨大学,经济学院)这篇论文考查了OECD的11个国家中现金流量对企业投资的影响.我们发现不同国家之间投资对企业内部可获取资金的敏感性具有显著差异,并且银企之间具有明显的紧密关系的国家的敏感性比银企之间具有公平关系的国家的低.同时,我们发现融资约束与整体金融发展指标不存在关系.我们的结论与资本市场信息和激励问题对企业投资具有重要作用这种观点一致,并且紧密的银企关系会减少这些问题从而增加企业获取外部融资的渠道。

一、引言各个国家的企业在显著不同的金融体制下运行。

金融发展水平的差别(例如,相对GDP的信用额度和相对GDP的相应股票市场的资本化程度),在所有者和管理者关系、企业和债权人的模式中,企业控制的市场活动水平可以很好地被记录.在完美资本市场,对于具有正的净现值投资机会的企业将一直获得资金。

然而,经济理论表明市场摩擦,诸如信息不对称和激励问题会使获得外部资本更加昂贵,并且具有盈利投资机会的企业不一定能够获取所需资本.这表明融资要素,例如内部产生资金数量、新债务和权益的可得性,共同决定了企业的投资决策.现今已经有大量考查外部资金可得性对投资决策的影响的实证资料(可参考,例如Fazzari(1998)、 Hoshi(1991)、 Chapman(1996)、Samuel(1998)).大多数研究结果表明金融变量例如现金流量有助于解释企业的投资水平。

这项研究结果解释表明企业投资受限于外部资金的可得性。

很多模型强调运行正常的金融中介和金融市场有助于改善信息不对称和交易成本,减缓不对称问题,从而促使储蓄资金投着长期和高回报的项目,并且提高资源的有效配置(参看Levine(1997)的评论文章)。

因而我们预期用于更加发达的金融体制的国家的企业将更容易获得外部融资.几位学者已经指出建立企业和金融中介机构可进一步缓解金融市场摩擦。

毕业设计外文翻译译文

毕业设计外文翻译译文

1 工程概论1.1 工程专业1.2 工业和技术1.3 现代制造业工程专业1 工程行业是历史上最古老的行业之一。

如果没有在广阔工程领域中应用的那些技术,我们现在的文明绝不会前进。

第一位把岩石凿削成箭和矛的工具匠是现代机械工程师的鼻祖。

那些发现地球上的金属并找到冶炼和使用金属的方法的工匠们是采矿和冶金工程师的先祖。

那些发明了灌溉系统并建造了远古世纪非凡的建筑物的技师是他们那个时代的土木工程师。

2 工程一般被定义为理论科学的实际应用,例如物理和数学。

许多早期的工程设计分支不是基于科学而是经验信息,这些经验信息取决于观察和经历,而不是理论知识。

这是一个倾斜面实际应用的例子,虽然这个概念没有被确切的理解,但是它可以被量化或者数字化的表达出来。

3 从16、17世纪当代初期,量化就已经成为科学知识大爆炸的首要原因之一。

另外一个重要因素是实验法验证理论的发展。

量化包含了把来源于实验的数据和信息转变成确切的数学术语。

这更加强调了数学是现代工程学的语言。

4 从19世纪开始,它的结果的实际而科学的应用已经逐步上升。

机械工程师现在有精确的能力去计算来源于许多不同机构之间错综复杂的相互作用的机械优势。

他拥有能一起工作的既新型又强硬的材料和巨大的新能源。

工业革命开始于使用水和蒸汽一起工作。

从此使用电、汽油和其他能源作动力的机器变得如此广泛以至于它们承担了世界上很大比例的工作。

5 科学知识迅速膨胀的结果之一就是科学和工程专业的数量的增加。

到19世纪末不仅机械、土木、矿业、冶金工程被建立而且更新的化学和电气工程专业出现了。

这种膨胀现象一直持续到现在。

我们现在拥有了核能、石油、航天航空空间以及电气工程等。

每种工程领域之内都有细分。

6 例如,土木工程自身领域之内有如下细分:涉及永久性结构的建筑工程、涉及水或其他液体流动与控制系统的水利工程、涉及供水、净化、排水系统的研究的环境工程。

机械工程主要的细分是工业工程,它涉及的是错综复杂的机械系统,这些系统是工业上的,而非单独的机器。

本科毕业设计的英文资料与中文翻译

本科毕业设计的英文资料与中文翻译

英文资料与中文翻译IEEE 802.11 MEDIUM ACCESS CONTROLThe IEEE 802.11 MAC layer covers three functional areas:reliable data delivery, medium access control, and security. This section covers the first two topics.Reliable Data DeliveryAs with any wireless network, a wireless LAN using the IEEE 802.11 physical and MAC layers is subject to considerable unreliability. Noise, interference, and other propagation effects result in the loss of a significant number of frames. Even with error-correction codes, a number of MAC frames may not successfully be received. This situation can be dealt with by reliability mechanisms at a higher layer. such as TCP. However, timers used for retransmission at higher layers are typically on the order of seconds. It is therefore more efficient to deal with errors at the MAC level. For this purpose, IEEE 802.11 includes a frame exchange protocol. When a station receives a data frame from another station. It returns an acknowledgment (ACK) frame to the source station. This exchange is treated as an atomic unit, not to be interrupted by a transmission from any other station. If the source does not receive an ACK within a short period of time, either because its data frame was damaged or because the returning ACK was damaged, the source retransmits the frame.Thus, the basic data transfer mechanism in IEEE802.11 involves an exchange of two frames. To further enhance reliability, a four-frame exchange may be used. In this scheme, a source first issues a request to send (RTS) frame to the destination. The destination then responds with a clear to send (CTS). After receiving the CTS, the source transmits the data frame, and the destination responds with an ACK. The RTS alerts all stations that are within reception range of the source that an exchange is under way; these stations refrain from transmission in order to avoid a collision between two frames transmitted at the same time. Similarly, the CTS alerts all stations that are within reception range of the destination that an exchange is under way. The RTS/CTS portion of the exchange is a required function of the MAC but may be disabled.Medium Access ControlThe 802.11 working group considered two types of proposals for a MAC algorithm: distributed access protocols, which, like Ethernet, distribute the decision to transmit over all the nodes using a carrier-sense mechanism; and centralized access protocols, which involve regulation of transmission by a centralized decision maker. A distributed access protocol makes sense for an ad hoc network of peer workstations (typically an IBSS) and may also be attractive in other wireless LAN configurations that consist primarily of burst traffic. A centralized access protocol is natural for configurations in which a umber of wireless stations are interconnected with each other and some sort of base station that attaches to a backbone wired LAN: it is especially useful if some of the data is time sensitive or high priority.The end result for 802.11 is a MAC algorithm called DFWMAC (distributed foundation wireless MAC) that provides a distributed access control mechanism with an optional centralized control built on top of that. Figure 14.5 illustrates the architecture. The lower sub-layer of the MAC layer is the distributed coordination function (DCF). DCF uses a contention algorithm to provide access to all traffic. Ordinary asynchronous traffic directly uses DCE. The point coordination function (PCF) is a centralized MAC algorithm used to provide contention-free service. PCF is built on top of DCF and exploits features of DCF to assure access for its users. Let us consider these two sub-layers in turn.MAClayerFigure 14.5 IEEE 802.11 Protocol ArchitectureDistributed Coordination FunctionThe DCF sub-layer makes use of a simple CSMA (carrier sense multiple access) algorithm, which functions as follows. If a station has a MAC frame to transmit, it listens to the medium. If the medium is idle, the station may transmit; otherwise the station must wait until the current transmission is complete before transmitting. The DCF does not include a collision detection function (i.e. CSMA/CD) because collision detection is not practical on a wireless network. The dynamic range of the signals on the medium is very large, so that a transmitting station cannot effectively distinguish incoming weak signals from noise and the effects of its own transmission.To ensure the smooth and fair functioning of this algorithm, DCF includes a set of delays that amounts to a priority scheme. Let us start by considering a single delay known as an inter-frame space (IFS). In fact, there are three different IFS values, but the algorithm is best explained by initially ignoring this detail. Using an IFS, the rules for CSMA access are as follows (Figure 14.6):Figure 14.6 IEEE 802.11 Medium Access Control Logic1. A station with a frame to transmit senses the medium. If the medium is idle. It waits to see if the medium remains idle for a time equal to IFS. If so , the station may transmit immediately.2. If the medium is busy (either because the station initially finds the medium busy or because the medium becomes busy during the IFS idle time), the station defers transmission and continues to monitor the medium until the current transmission is over.3. Once the current transmission is over, the station delays another IFS. If the medium remains idle for this period, then the station backs off a random amount of time and again senses the medium. If the medium is still idle, the station may transmit. During the back-off time, if the medium becomes busy, the back-off timer is halted and resumes when the medium becomes idle.4. If the transmission is unsuccessful, which is determined by the absence of an acknowledgement, then it is assumed that a collision has occurred.To ensure that back-off maintains stability, a technique known as binary exponential back-off is used. A station will attempt to transmit repeatedly in the face of repeated collisions, but after each collision, the mean value of the random delay is doubled up to some maximum value. The binary exponential back-off provides a means of handling a heavy load. Repeated failed attempts to transmit result in longer and longer back-off times, which helps to smooth out the load. Without such a back-off, the following situation could occur. Two or more stations attempt to transmit at the same time, causing a collision. These stations then immediately attempt to retransmit, causing a new collision.The preceding scheme is refined for DCF to provide priority-based access by the simple expedient of using three values for IFS:●SIFS (short IFS):The shortest IFS, used for all immediate responseactions,as explained in the following discussion●PIFS (point coordination function IFS):A mid-length IFS, used by thecentralized controller in the PCF scheme when issuing polls●DIFS (distributed coordination function IFS): The longest IFS, used as aminimum delay for asynchronous frames contending for access Figure 14.7a illustrates the use of these time values. Consider first the SIFS.Any station using SIFS to determine transmission opportunity has, in effect, the highest priority, because it will always gain access in preference to a stationwaiting an amount of time equal to PIFS or DIFS. The SIFS is used in the following circumstances:●Acknowledgment (ACK): When a station receives a frame addressed onlyto itself (not multicast or broadcast) it responds with an ACK frame after, waiting on1y for an SIFS gap. This has two desirable effects. First, because collision detection IS not used, the likelihood of collisions is greater than with CSMA/CD, and the MAC-level ACK provides for efficient collision recovery. Second, the SIFS can be used to provide efficient delivery of an LLC protocol data unit (PDU) that requires multiple MAC frames. In this case, the following scenario occurs. A station with a multi-frame LLC PDU to transmit sends out the MAC frames one at a time. Each frame is acknowledged after SIFS by the recipient. When the source receives an ACK, it immediately (after SIFS) sends the next frame in the sequence. The result is that once a station has contended for the channel, it will maintain control of the channel until it has sent all of the fragments of an LLC PDU.●Clear to Send (CTS):A station can ensure that its data frame will getthrough by first issuing a small. Request to Send (RTS) frame. The station to which this frame is addressed should immediately respond with a CTS frame if it is ready to receive. All other stations receive the RTS and defer using the medium.●Poll response: This is explained in the following discussion of PCF.longer than DIFS(a) Basic access methodasynchronous trafficdefers(b) PCF super-frame constructionFigure 14.7 IEEE 802.11 MAC TimingThe next longest IFS interval is the: PIFS. This is used by the centralized controller in issuing polls and takes precedence over normal contention traffic. However, those frames transmitted using SIFS have precedence over a PCF poll.Finally, the DIFS interval is used for all ordinary asynchronous traffic.Point C00rdination Function PCF is an alternative access method implemented on top of the DCE. The operation consists of polling by the centralized polling master (point coordinator). The point coordinator makes use of PIFS when issuing polls. Because PI FS is smaller than DIFS, the point coordinator call seize the medium and lock out all asynchronous traffic while it issues polls and receives responses.As an extreme, consider the following possible scenario. A wireless network is configured so that a number of stations with time, sensitive traffic are controlled by the point coordinator while remaining traffic contends for access using CSMA. The point coordinator could issue polls in a round—robin fashion to all stations configured for polling. When a poll is issued, the polled station may respond using SIFS. If the point coordinator receives a response, it issues another poll using PIFS. If no response is received during the expected turnaround time, the coordinator issues a poll.If the discipline of the preceding paragraph were implemented, the point coordinator would lock out all asynchronous traffic by repeatedly issuing polls. To prevent this, an interval known as the super-frame is defined. During the first part of this interval, the point coordinator issues polls in a round, robin fashion to all stations configured for polling. The point coordinator then idles for the remainder of the super-frame, allowing a contention period for asynchronous access.Figure l4.7 b illustrates the use of the super-frame. At the beginning of a super-frame, the point coordinator may optionally seize control and issues polls for a give period of time. This interval varies because of the variable frame size issued by responding stations. The remainder of the super-frame is available for contention based access. At the end of the super-frame interval, the point coordinator contends for access to the medium using PIFS. If the medium is idle. the point coordinator gains immediate access and a full super-frame period follows. However, the medium may be busy at the end of a super-frame. In this case, the point coordinator must wait until the medium is idle to gain access: this result in a foreshortened super-frame period for the next cycle.OctetsFC=frame control SC=sequence controlD/I=duration/connection ID FCS=frame check sequence(a ) MAC frameBitsDS=distribution systemMD=more data MF=more fragmentsW=wired equivalent privacy RT=retryO=orderPM=power management (b) Frame control filedFigure 14.8 IEEE 802.11 MAC Frame FormatMAC FrameFigure 14.8a shows the 802.11 frame format when no security features are used. This general format is used for all data and control frames, but not all fields are used in all contexts. The fields are as follows:● Frame Control: Indicates the type of frame and provides contr01information, as explained presently.● Duration/Connection ID: If used as a duration field, indicates the time(in-microseconds) the channel will be allocated for successful transmission of a MAC frame. In some control frames, this field contains an association, or connection, identifier.●Addresses: The number and meaning of the 48-bit address fields dependon context. The transmitter address and receiver address are the MAC addresses of stations joined to the BSS that are transmitting and receiving frames over the wireless LAN. The service set ID (SSID) identifies the wireless LAN over which a frame is transmitted. For an IBSS, the SSID isa random number generated at the time the network is formed. For awireless LAN that is part of a larger configuration the SSID identifies the BSS over which the frame is transmitted: specifically, the SSID is the MAC-level address of the AP for this BSS (Figure 14.4). Finally the source address and destination address are the MAC addresses of stations, wireless or otherwise, that are the ultimate source and destination of this frame. The source address may be identical to the transmitter address and the destination address may be identical to the receiver address.●Sequence Control: Contains a 4-bit fragment number subfield used forfragmentation and reassembly, and a l2-bit sequence number used to number frames sent between a given transmitter and receiver.●Frame Body: Contains an MSDU or a fragment of an MSDU. The MSDUis a LLC protocol data unit or MAC control information.●Frame Check Sequence: A 32-bit cyclic redundancy check. The framecontrol filed, shown in Figure 14.8b, consists of the following fields.●Protocol Version: 802.11 version, current version 0.●Type: Identifies the frame as control, management, or data.●Subtype: Further identifies the function of frame. Table 14.4 defines thevalid combinations of type and subtype.●To DS: The MAC coordination sets this bit to 1 in a frame destined to thedistribution system.●From DS: The MAC coordination sets this bit to 1 in a frame leaving thedistribution system.●More Fragments: Set to 1 if more fragments follow this one.●Retry: Set to 1 if this is a retransmission of a previous frame.●Power Management: Set to]if the transmitting station is in a sleep mode.●More Data: Indicates that a station has additional data to send. Each blockof data may be sent as one frame or a group of fragments in multiple frames.●WEP:Set to 1 if the optional wired equivalent protocol is implemented.WEP is used in the exchange of encryption keys for secure data exchange.This bit also is set if the newer WPA security mechanism is employed, as described in Section 14.6.●Order:Set to 1 in any data frame sent using the Strictly Ordered service,which tells the receiving station that frames must be processed in order. We now look at the various MAC frame types.Control Frames Control frames assist in the reliable delivery of data frames. There are six control frame subtypes:●Power Save-Poll (PS-Poll): This frame is sent by any station to the stationthat includes the AP (access point). Its purpose is to request that the AP transmit a frame that has been buffered for this station while the station was in power saving mode.●Request to Send (RTS):This is the first frame in the four-way frameexchange discussed under the subsection on reliable data delivery at the beginning of Section 14.3.The station sending this message is alerting a potential destination, and all other stations within reception range, that it intends to send a data frame to that destination.●Clear to Send (CTS): This is the second frame in the four-way exchange.It is sent by the destination station to the source station to grant permission to send a data frame.●Acknowledgment:Provides an acknowledgment from the destination tothe source that the immediately preceding data, management, or PS-Poll frame was received correctly.●Contention-Free (CF)-End: Announces the end of a contention-freeperiod that is part of the point coordination function.●CF-End+CF-Ack:Acknowledges the CF-End. This frame ends thecontention-free period and releases stations from the restrictions associated with that period.Data Frames There are eight data frame subtypes, organized into two groups. The first four subtypes define frames that carry upper-level data from the source station to the destination station. The four data-carrying frames are as follows: ●Data: This is the simplest data frame. It may be used in both a contentionperiod and a contention-free period.●Data+CF-Ack: May only be sent during a contention-free period. Inaddition to carrying data, this frame acknowledges previously received data.●Data+CF-Poll: Used by a point coordinator to deliver data to a mobilestation and also to request that the mobile station send a data frame that it may have buffered.●Data+CF-Ack+CF-Poll: Combines the functions of the Data+CF-Ack andData+CF-Poll into a single frame.The remaining four subtypes of data frames do not in fact carry any user data. The Null Function data frame carries no data, polls, or acknowledgments. It is used only to carry the power management bit in the frame control field to the AP, to indicate that the station is changing to a low-power operating state. The remaining three frames (CF-Ack, CF-Poll,CF-Ack+CF-Poll) have the same functionality as the corresponding data frame subtypes in the preceding list (Data+CF-Ack, Data+CF-Poll, Data+CF-Ack+CF-Poll) but withotit the data. Management FramesManagement frames are used to manage communications between stations and APs. The following subtypes are included:●Association Request:Sent by a station to an AP to request an association,with this BSS. This frame includes capability information, such as whether encryption is to be used and whether this station is pollable.●Association Response:Returned by the AP to the station to indicatewhether it is accepting this association request.●Reassociation Request: Sent by a station when it moves from one BSS toanother and needs to make an association with tire AP in the new BSS. The station uses reassociation rather than simply association so that the new AP knows to negotiate with the old AP for the forwarding of data frames.●Reassociation Response:Returned by the AP to the station to indicatewhether it is accepting this reassociation request.●Probe Request: Used by a station to obtain information from anotherstation or AP. This frame is used to locate an IEEE 802.11 BSS.●Probe Response: Response to a probe request.●Beacon: Transmitted periodically to allow mobile stations to locate andidentify a BSS.●Announcement Traffic Indication Message: Sent by a mobile station toalert other mobile stations that may have been in low power mode that this station has frames buffered and waiting to be delivered to the station addressed in this frame.●Dissociation: Used by a station to terminate an association.●Authentication:Multiple authentication frames are used in an exchange toauthenticate one station to another.●Deauthentication:Sent by a station to another station or AP to indicatethat it is terminating secure communications.IEEE802.11 媒体接入控制IEEE 802.11 MAC层覆盖了三个功能区:可靠的数据传送、接入控制以及安全。

毕业设计论文外文文献翻译

毕业设计论文外文文献翻译

毕业设计(论文)外文文献翻译院系:财务与会计学院年级专业:201*级财务管理姓名:学号:132148***附件: 财务风险管理【Abstract】Although financial risk has increased significantly in recent years risk and risk management are not contemporary issues。

The result of increasingly global markets is that risk may originate with events thousands of miles away that have nothing to do with the domestic market。

Information is available instantaneously which means that change and subsequent market reactions occur very quickly。

The economic climate and markets can be affected very quickly by changes in exchange rates interest rates and commodity prices。

Counterparties can rapidly become problematic。

As a result it is important to ensure financial risks are identified and managed appropriately. Preparation is a key component of risk management。

【Key Words】Financial risk,Risk management,YieldsI. Financial risks arising1.1What Is Risk1.1.1The concept of riskRisk provides the basis for opportunity. The terms risk and exposure have subtle differences in their meaning. Risk refers to the probability of loss while exposure is the possibility of loss although they are often used interchangeably。

毕业设计中英文翻译

毕业设计中英文翻译

本科生毕业设计(论文)外文翻译毕业设计(论文)题目:电力系统检测与计算外文题目:The development of the single chipmicrocomputer译文题目:单片机技术的发展与应用学生姓名: XXX专业: XXX指导教师姓名: XXX评阅日期:单片机技术的发展与应用从无线电世界到单片机世界现代计算机技术的产业革命,将世界经济从资本经济带入到知识经济时代。

在电子世界领域,从 20 世纪中的无线电时代也进入到 21 世纪以计算机技术为中心的智能化现代电子系统时代。

现代电子系统的基本核心是嵌入式计算机系统(简称嵌入式系统),而单片机是最典型、最广泛、最普及的嵌入式系统。

一、无线电世界造就了几代英才。

在 20 世纪五六十年代,最具代表的先进的电子技术就是无线电技术,包括无线电广播,收音,无线通信(电报),业余无线电台,无线电定位,导航等遥测、遥控、遥信技术。

早期就是这些电子技术带领着许多青少年步入了奇妙的电子世界,无线电技术展示了当时科技生活美妙的前景。

电子科学开始形成了一门新兴学科。

无线电电子学,无线通信开始了电子世界的历程。

无线电技术不仅成为了当时先进科学技术的代表,而且从普及到专业的科学领域,吸引了广大青少年,并使他们从中找到了无穷的乐趣。

从床头的矿石收音机到超外差收音机;从无线电发报到业余无线电台;从电话,电铃到无线电操纵模型。

无线电技术成为当时青少年科普、科技教育最普及,最广泛的内容。

至今,许多老一辈的工程师、专家、教授当年都是无线电爱好者。

无线电技术的无穷乐趣,无线电技术的全面训练,从电子学基本原理,电子元器件基础到无线电遥控、遥测、遥信电子系统制作,培养出了几代科技英才。

二、从无线电时代到电子技术普及时代。

早期的无线电技术推动了电子技术的发展,其中最主要的是真空管电子技术向半导体电子技术的发展。

半导体电子技术使有源器件实现了微小型化和低成本,使无线电技术有了更大普及和创新,并大大地开阔了许多非无线电的控制领域。

毕设设计类外文翻译

毕设设计类外文翻译

Interior Design Supports Art Education: A Case StudyInterior design, as a field of study, is a rapidly growing area of interest – particularly for teenagers in the United States. Part of this interest stems from the proliferation ofdesign-related reality shows available through television media. Some art educators and curriculum specialists in the nation perceive the study of interior spaces as a ‘practical application’ of the arts.This article discusses an experiential design problem, originally used in higher education interior design studio courses that was modified and shared with students in third grade to address national academic standards. Later, this same project was modified for use with high school students in the educator’s community a nd with international design students in South Korea.Lastly, the project was presented in a workshop to art education students at a higher education institution. The project was modified to address (1) the age group level and (2) a topic relevant to the audience. Goals of the design project were: (1) to explore creative problem-solving, (2) to explore the application of design elements and principles, and (3) to increase student understanding of spatial relationships within an interior environment. Findings indicate that the project supported several visual art standards, including perception and community. This project may be of interest to current and future art educators and others interested in the potential of interior design content supporting art education.IntroductionThe design of interior spaces is a growing area of interest in the United States. Studies indicate that people spend 90 per cent of their time indoors, thereby making the quality design of interiors critical to the health and welfare of the population. Youth have been unconsciously encouraged since their childhood to develop awareness of their personal interior spaces and furnishings through popular storybooks they read that introduce the awareness of scale, proportion and ergonomics at a very young age (e.g. Three Little Bears and Alice in Wonderland). More recently, teens in the United States have become unexpectedly ‘hooked’ on design related reality shows such as Trading Spaces, Changing Rooms and Design on a Dime. Although Trading Spaces was originally intended for adults, according to the Wall Street Journal article titled ‘The Teen-Room Makeover’ (18 October 2002) the audience has more than 125,000 viewers aged 12 to 17 [1]. In support of that finding, a survey conducted in 2003 for a national chain of hardware stores discovered 65 per cent of teens said they have watched home improvement-related television shows [2].Teens seemingly have a growing interest in the design of interior spaces.In the United States in 2002, a qualitative study was developed to determine if interior design subject-matter could support national academic standards in elementary and secondary schools (kindergarten – twelfth grade) [3]. Findings of the study indicated that art educators and curriculum specialists perceived interior design to be supportive in meeting their standards as a type of ‘practical application’ of the arts. Perceptions of the curriculum specialists indicated they were looking for new ways to interpret fine art standards in their existing curriculum and that interior design offered one solution. As a result, the researcher, who was an interior design educator, was encouraged to identify and develop a project or lesson plan that could introduce children and youth to the importance of well-designed interior spaces yet support an art education standard in the nation.This article discusses an experiential interior design project that was modified from an exercise used in the freshman and sophomore college studio classes and shared with students in third grade, high school, and with international students in South Korea by this interior design educator. The educator was later invited to present this project to art education teachers at her university. The project supported several school district visual art standards, including perception and community. It was modified to address (1) the age group level and (2) a topic relevant to the audience. Goals of the design project were: (1) to explore creative problem solving, (2) to explore the application of design elements and principles, and (3) to increase student understanding of spatial relationships within an interior environment. This project may be of interest to current and future art educators and others interested in the potential of interior design content supporting visual art standards.Review of literatureThe review of literature briefly discusses (1) experiential learning theory, (2) findings from a qualitative study involving art educators, and (3) the interior design link with art education. The interior design project description and process of application will follow.Experiential learningExperiential learning theory, as an application of cognitive/perceptual models, is a tool toenhance the cognitive process of students. Specifically, the experiential learning cycleinvolves a concrete experience that leads to observations and reflections then to formation of abstract concepts and generalisations, before finally testing implications from concepts in new situations [4].The Association for Experiential Education defines experiential education astheprocess by which a learner constructs knowledge, skill and value from direct experience [5]. Drengson [6] defines experiential education as the process of practical engagement withconcepts and skills applied in a practical setting and delivered through physical and practical mental activity.One of the key components to enhance student learning is reflection. Dewey [7] suggests that to have meaning, an experience must be combined with thought. Kolb [8] suggests that reflections can offer a potential source of powerful data to link theory to practice. The mental engagement of an experiential learner can involve questioning, investigation, experimentation, curiosity, problem-solving, assuming responsibility, creativity and the construction of meaning [9].Experiential learning offers the spontaneous opportunity for learning, whether from unplanned moments, natural consequences, mistakes or successes [10]. Holistically, it involves not only the cognitive but also any combination of the senses, the emotions, and the physical [11].Qualitative study involving art educatorsIn 2001, a study was conducted to determine if interior design may be supportive tokindergarten – twelfth grade (K–12) teachers in meeting national academic standards,including the arts [12]. To understand perceptions of experts in interior design and elementary and secondary education, five focus group session sand six personal interviews were conducted with interior design educators, practitioners,K–12 teachers (elementary, junior high, and high school levels), national standards curriculum specialists (local and state level), and school-to-career curriculum specialists from June 2001 to April 2002[13].Focus group findings indicated that K–12teachers, at both elementary and secondary levels, felt that interior design could be supportive in meeting visual art standards because youth are frequently analysing their personal and public spaces. Participants described specific examples of interior design materials they currently needed in their course work to include: examples of good and bad interior spaces, information about elements and principles of design as they relate to interior spaces, and hands-on col our wheels of sturdy materials. In addition they requested that the materials be low cost, stimulating,‘touchable’,recyclable, self-contained, and fun. Lesson plans the visual art teachers suggested included:• reinvention of the ‘shoe box’ projec t;• development of well-known stories (The Three Pigs, Three Little Bears, and Alice in Wonderland) into space models to teach proportion and scale. In addition, it was suggestedthe following lesson plan: use of Goldilocks story to analyse ‘client or consumer needs’;• use of a Dr Seuss story (literary passage) to generate a conceptual model that enhances creativity;• study of cultural spaces at the junior high level that would enhance study of personal expression of identity in interiors [14].The visual arts curriculum specialists indicated hat interior design –as a ‘practical application’ should be introduced in elementary levels where there is a ‘small window of opportunity’ to give good information about the visual arts. See Table 1 fo r an example of the visual art standards in kindergarten – third grade levels. One visual art specialist advocated that the design process was more important to teach than a particular design method. He suggested moving students from designing personal spaces – and the study of elements and principles of design – in elementary levels to the analysis of private and public spaces in the junior high level. Then the high school levels could be reserved for additional indepth Exploration.Today, junior high and high school students are quite attracted to design-related reality shows. Over the last five years, the number of designrelated television shows has increased dramatically [15]. Why are these shows so attractive to teens and young adults? Rodriguez [16]has suggested that this interest is linked to the teens need for expression of self andself-identity.An individual’s unique identity is established through personalisation of space, which is critical to overall development of self [17]. Developing a sense of self involves the use of symbols to communicate to others one’s personal underlying identity.Interior design link with art educationIt is not common for interior design to be linked with art education in K–12 grade levels in the United States. However, the Foundation for Interior Design EducationResearch[18]standards and guidelines – the accreditation organization for higher education interior design programmes in the nation – reveal that there are many shared areas between visual arts and interior design (e.g.elements and principles of design).Rasmussen and Wright [19]advocate the need for a new model for art education. The new model should offer youth an aesthetic education that does more than just serve the traditional concerns of established arts curriculum. Experiences indicate that young people try to make sense of their own lives by creating contextual understanding through actively, and intentionally, making connections to signs, perceptions and experiences. This is a challenge to develop a new art education model that creates a balance between social andcontextual needs, knowledge of young people, and theaesthetic medium itself.The study of interior spaces offers one such context for learning in the physical environment.People spend 90 per cent of their time in interior spaces [20]. Youth consciously or unconsciously, analyse and respond to their near environment. They also learn best if they understand why they are learning what they are learning. Application of design and art to everyday life can assist in making connections in student learning, and develop more awareness of good design as well as an appreciation of the arts. Youth need theopportunity to learn more about design and human behavior so they can learn they have choices about how supportive their environments can be. Children can [determine] how design influences their behaviors; howdesign can be used to manipulate behavior; how design can encourage or discourage conversation, establish status, put people in power positions, increase or decrease anxiety [21].Therefore, based on (1) the experiential learning theoretical underpinnings, (2) recommendations made by art educators and curriculum specialists, and (3) a call for a new ways of teaching art education, an interior design educator at a higher education institution modified an experiential design project that involved the use of elements and principles of design and an opportunity for self-expression of personal spaces. The designproblem of the personal space was changed based on the grade level.Case study project descriptionAlthough art educators and curriculum specialists perceived that interior design content could be supportive to visual art standards, it was determined that a case study project needed to be developed and presented to various grade levels. It was also determined that a conceptual model of interior spaces should be used toenhance student creativity and exploration rather than a finite model that would offer too many rules and boundaries. Project descriptionThe experiential interior design project involved the construction of athree-dimensional concept model using 44 triangular and rectangular pieces of cardstock (stiff) paper in a neutral colour [22]. The objective was to discover, manipulate and create interior spaces based on a given design problem (e.g. design your space station on a planet of your choice or design your home in the Rocky Mountains of Colorado). The purpose ofthe project was to encourage students to design a conceptual structure from the interior out, keep-ing in mind the function of the building. The student’s model had to incorporate a minimum of six spaces and three levels to encourage vertical as well as horizontal volumes. All 44 pieces of cardstock had to be used in the finished model, which sometimes posed achallenge to the youth. The cardstock pieces could not be ripped, torn, or pierced. However, they could be bent and shapedaccording to the whim of the student.Flow from one space to another and one level to another was emphasized. The decision-making design process was explained and encouraged.Outcomes consisted of a three-dimensional abstract model which, if successfully executed, demonstrated the break-down of traditional spatial paradigms. Design problemsEach student grade level was given a different design problem based on the academic standards that were to be met in that class. In some cases, several academic standards were addressed at the same time. Two national standards for visual arts in the United States were selected to be supported with this project: communication and perception. The communication standard indicates that students in kindergarten – third grade should recognise the use of the visual arts as a means of communication (e.g. select and use visual images, themes and ideas in their own work). The perception standard indicates that students know, understand and apply elements of visual arts and principles of design (e.g. Identify elements and principles of design).Third grade studentsAfter procuring appropriate permission, the design educator brought volunteer college-age interior design students to the elementary school to help administer the project. Three third grade classes (twenty students in each class) had just finished a science unit on space and orbits and were studying specific visual art standards. The children were asked to design a personal space station on a planet of their choice. The goal was to help students relate the newly learned science information to something in real life (e.g. Their home), yet encourage exploration of visual arts (see Figs. 2–4).Each team of students was given the same 44 pieces of cardstock (all cut out) in a plastic bag, a cardboard base (15” x 15” square) on which to build the model, and cellophane tape to use in constructing the model. To enhance reflection of this experiential project, each team of three students was asked to give a two-minute verbal presentation in front of the class on their finished model. In this manner, they could discuss their design solution and the design educator could assess their use of creativity through design elements and principles.The college students and design educator rotated through the three classrooms of students to answer questions, encourage use of design elements and principles, and applaud their creative exploration. The third grade teachers assisted in supporting the structure of the class and encouraging shy students who were reluctant to begin.It was interesting to observe that the children rarely built the models on their provided classroom tables. Instead,they moved to the floor space, located the base for the model in between team members, and began construction. Each team member assumed a role in the process. One team member seemed t o act as the ‘designer’, one as the ‘builder/construction crew’ and the last as the ‘supplier’ of materials. Students excitedlydiscussed the positioning of the triangular pieces of cardstock in their model, their rooms in their space stations, and the different ways to turn the model to create different vantage points.The teams of third graders had one hour to complete the models. Then their verbal presentations began, interspersed with questions and comments from the design educator and third grade teachers. Informal observations indicatedthat application of design elements and principles was strong – perhaps due to the consistent rectangular and triangular shapes that had been provided – thereby supporting the visual arts perception standard. Manipulation of shapes was innovative. Line, shape and form were used to provide movement through adjoining spaces and offered a sense of verticality. Interior volumes were created that supported human behaveour in interior spaces. For example, one team’s presentation discussed how their space station boasted an exercise room with trampolines to strengthen human muscles that weakened as a result of zero gravity in outer space. The communication standard was supported in their finished models in a couple ways. First there was a theme of design as it relates to protection from foreign objects. For example, one team’s space station on Saturn incorporated a force field to protect it from flying rocks. Other visual themes of security and safety evoked the implementation of security cameras, alien detectors, missile launchers, telescope laboratories, control stations and transport rooms. Another visual theme related to circulation. Circulation within the structure was depicted by the third graders through the use of escalators, stairs, elevators and poles. A third visual theme was unique human needs as they relate to interior spaces. Almost every team’s space station incorporated a room for their mothers! In addition, depending on the students’ personal interests, unique space station features ranged from chemical rooms to sandboxes. It was obvious in their multiple unique design solutions their use of creativity had been explored and enhanced.Evaluation and assessment that took place, after the classes were dismissed, indicated that the third grade teachers perceived that this experiential design project supported the visual arts standards in both the communication and perception components as well as the third grade science academic standard concerning space and orbits. In addition, the experiential component of the project had unexpected results when certain quiet, unassuming students in the class became animated and highly engaged in learning. One teacher shared her excitement with the design educator about a new connection that wasformed with one of students that she had not been able to connect with before the design exercise.High school studentsAfter the case study with the third grade students, it was determined to offer this project to high school students. Diversity students in a nearby community were invited to attend a complimentary design workshop at a local library. The interior design educator was asked to present a design problem that would relate to arteducation (see Figs. 6–8).Their problem was to use the same experiential project and shapes to design and construct a conceptual model of their new home or cabin in the Rocky Mountain region. The same project constraints existed. Due to the students’ ages, discussions took place prior to the exercise about innovative problem-solving, the exploration of creativity and the elements and principles of design used within the design process. Some of these elements and principles included:Scale. Awareness of human scale was addressed to develop understanding of proportion and scale of the structure and interior spaces. Shape. Triangular shapes were deliberately selected to encourage students to break paradigms of rectangular interior spaces.Colour. The cardstock pieces were of a neutral colour to enhance spatial composition rather than draw attention to colour usage or juxtaposition. Volume/Mass. The mass of thethree-dimensional model was important in communicating the use of common elements and principles of design (e.g. line, rhythm). Line. A variety of different lines (e.g. diagonal, horizontal) were investigated in the manipulation of the shapes. Space. Space was created through the manipulation of shapes. Theories of complexity, mystery and refuge within interior spaces were discussed. Informal assessment of the finished design models indicated that the design solutions werevery creative.Later that semester, by invitation, the same design project was taken to college students training to be art educators in a mini-workshop format. The art education students found the exercise effective in enhancing creativity and understanding how interior design can enhance understanding of visual arts.International studentsAlthough there was no intention to meet a national visual arts academic standard at a specific grade level, this same experiential design project was presented in Seoul, South Korea to college-aged international students. The design problem was to use the same 44 pieces to develop a design concept model for acommercial building in Seoul. Language translators were used to help the design educatorintroduce the project, guide the students through the process, and understand their verbal presentations at the end of the workshop.Students commented during and after the workshop how the model enhanced their visual literacy skills (they used different words) and creativity within the context of everyday life. The experiential nature of the workshop was seemingly a pleasure to them (see Figs.9–11).Discussion and conclusionThis interior design case study project was designed to be experiential in nature to enhance student learning of the visual arts. Student and teacher assessment of the various groups indicated enthusiasm for the design project because it enhanced creativity, explored multiple design solutions, related to real life, and increased their understanding of human behaviour within the context of the physical environment. Teacherassessment of the age groups indicated that the project did support visual art standards at the appropriate grade level. In addition, their assessment indicated satisfaction with the manner in which the interior design project encouraged student usage of the design elements and principles and the application of design to everyday living. Several instructors indicated that quiet and shy students in their class became engaged in the learning process, which had not been previously observed. Perception of art educators and art education students was that this project supported a variety of visual art standards such as perception and communication. This interior design case study project can be modified for various age and cultural groups and may be of interest to educators who are interested in working collaboratively with colleagues from other disciplines.Visual art programmes in the United States are being cut from the K–12 curriculum. By linking visual arts to an up-and-coming aesthetic field, such as interior design, there may be new ways to sustain and grow visual art programmes in the nation.References1. Orndoff, K. (2003) ASID American Society of Interior Designers 2003 Strategic Environment Report. Future Impact Education, p. 9.2. Levitz, S. (2004) Teens Hooked on Home Décor, London Free Press (Ontario, CA), 24 June, p. D2.3. Clemons, S. (2002) Collaborative Links with K–12: A Proposed Model Integrating Interior Design with National Education Standards, Journal of Interior Design, Vol. 28, No. 1, pp.40–8.4. Rubin, S. G. (1983) Overcoming Obstacles to Institutionalization of Experiential Learning Programs, New Directions for Experiential Learning, Vol. 20, pp. 43–54.5. Luckman, C. (1996) Defining Experiential Education, Journal of Experiential Education, Vol. 19, No. 1, pp. 6–7.6. Drengson, A. R. (1995) What Means this Experience? in Kraft, R. J. & Sokofs, M. [Eds] The Theory of Experiential Education. Boulder, CO: Association for Experiential Education, pp. 87–93.7. Dewey, J. (1916) Democracy and Education. New York: Macmillan.8. Kolb, D. A. (1984). Experiential Learning: Experience as the Sources of Learning and Development. Englewood Cliffs, NJ: Prentice-Hall.9. Luckmann, C. op. cit.10. Ibid.11. Carver, R. (1996) Theory for Practice: A Framework for Thinking about Experiential Education, Journal of Experiential Education, Vol. 19, No. 1, pp. 8–13.12. Clemons, S. op. cit.13. Ibid.14. Ibid.15. Bien, L. (2003) Renovating how-to TV Shows in a Race to Duplicate Success of ‘Trading Spaces’. The Post Standard (Syracuse, NY), 31 October, p. E1.16. Rodriguez, E. M. (2003) Starting Young, Miami Herald, 28 December, p. H–1.17. Baillie S. & Goeters, P. (1997) Home as a Developmental Environment. Proceedings of the American Association of Housing Educators, New Orleans, LA, pp. 32–6.18. Foundation of Interior Design Education Research (FIDER) home page. Available from URL: / (Accessed 4th January 2005).19. Rasmussen, B & Wright, P. (2001) The theatre workshop as educational space: How imagined reality is voiced and conceived, International Journal of Education & the Arts, Vol. 2, No. 2, pp.1–13.20. Environmental Protection Agency (2006) An Introduction to Indoor Air Quality (online). Available from URL: /iaq/ ia-intro.html (Accessed 26th September 2006).21. InformeDesign (n.d.) Implications, Vol. 1, No. 2, p. 2 (online). Available from URL: /# (Accessed 4th January 2005).22. Curfman, J. & Clemons, S. (1992) From Forty-Four Pieces to a New Spatial Paradigm, in Birdsong, C. [Ed.] Proceedings of the Interior Design Educators Council Southwest Regional Meeting, New Orleans, pp. 2–4./detail/refdetail?tablename=SJWD_U&filename=SJWD00000744102&uid=WEEvR EcwSlJHSldSdnQ0SWZDdUlMV1dWZi9tOGkyYTBaTzBVQjVYeENXYVp4MVRJQjI3cmZRYS9YRmhvdnlxazJRPT 0=$9A4hF_YAuvQ5obgVAqNKPCYcEjKensW4IQMovwHtwkF4VYPoHbKxJw!!Interior Design in Augmented Reality EnvironmentABSTRACTThis article presents an application of Augmented Realitytechnology for interior design. Plus, an Educational InteriorDesign Project is reviewed. Along with the dramatic progress ofdigital technology, virtual information techniques are alsorequired for architectural projects. Thus, the new technology ofAugmented Reality offers many advantages for digitalarchitectural design and construction fields. AR is also beingconsidered as a new design approach for interior design. In an ARenvironment, the virtual furniture can be displayed and modifiedin real-time on the screen, allowing the user to have an interactiveexperience with the virtual furniture in a real-world environment.Here, AR environment is exploited as the new workingenvironment for architects in architectural design works, and thenthey can do their work conveniently as such collaborativediscussion through AR environment. Finally, this study proposesa newmethod for applying AR technology to interior designwork, where a user can view virtual furniture and communicatewith 3D virtual furniture data using a dynamic and flexible userinterface. Plus, all the properties of the virtual furniture can beadjusted using occlusion- based interaction method for a TangibleAugmented Reality. General TermsApplications of computer science in modeling, visualization andmultimedia, graphics and imaging, computer vision, human-computerinteraction, et al.KeywordsAugmented Reality, Tangible AR, CAAD, ARToolKit, Interiordesign.1. INTRODUCTIONVisualizing how a particular table or chair will look in a roombefore it is decorated is a difficult challenge for anyone. Hence,Augmented Reality (AR) technology has been proposed forinterior design applications by few previous authors, for example,Koller, C. Wooward, A. Petrovski; K. Hirokazu, et al. The relateddevices typically include data glassesconnected to a。

本科毕业设计外文文献翻译

本科毕业设计外文文献翻译

(Shear wall st ructural design ofh igh-lev el fr ameworkWu Jiche ngAbstract : In t his pape r the basic c oncepts of man pow er from th e fra me sh ear w all str uc ture, analy sis of the struct ur al des ign of th e c ont ent of t he fr ame she ar wall, in cludi ng the seism ic wa ll she ar spa本科毕业设计外文文献翻译学校代码: 10128学 号:题 目:Shear wall structural design of high-level framework 学生姓名: 学 院:土木工程学院 系 别:建筑工程系 专 业:土木工程专业(建筑工程方向) 班 级:土木08-(5)班 指导教师: (副教授)nratiodesign, and a concretestructure in themost co mmonly usedframe shear wallstructurethedesign of p oints to note.Keywords: concrete; frameshearwall structure;high-risebuildingsThe wall is amodern high-rise buildings is an impo rtant buildingcontent, the size of theframe shear wall must comply with building regulations. The principle is that the largersizebut the thicknessmust besmaller geometric featuresshouldbe presented to the plate,the force is close to cylindrical.The wall shear wa ll structure is a flatcomponent. Itsexposure to the force along the plane level of therole ofshear and moment, must also take intoaccountthe vertical pressure.Operate under thecombined action ofbending moments and axial force andshear forcebythe cantilever deep beam under the action of the force levelto loo kinto the bottom mounted on the basis of. Shearwall isdividedinto a whole walland theassociated shear wall in theactual project,a wholewallfor exampl e, such as generalhousingconstruction in the gableor fish bone structure filmwalls and small openingswall.Coupled Shear walls are connected bythecoupling beam shear wall.Butbecause thegeneralcoupling beamstiffness is less thanthe wall stiffnessof the limbs,so. Walllimb aloneis obvious.The central beam of theinflection pointtopay attentionto thewall pressure than the limits of the limb axis. Will forma shortwide beams,widecolumn wall limbshear wall openings toolarge component atbothen ds with just the domain of variable cross-section ro din the internalforcesunder theactionof many Walllimb inflection point Therefore, the calcula tions and construction shouldAccordingtoapproximate the framestructure to consider.The designof shear walls shouldbe based on the characteristics of avariety ofwall itself,and differentmechanical ch aracteristicsand requirements,wall oftheinternalforcedistribution and failuremodes of specific and comprehensive consideration of the design reinforcement and structural measures. Frame shear wall structure design is to consider the structure of the overall analysis for both directionsofthehorizontal and verticaleffects. Obtain theinternal force is required in accordancewiththe bias or partial pull normal section forcecalculation.The wall structure oftheframe shear wall structural design of the content frame high-rise buildings, in the actual projectintheuse of themost seismic walls have sufficient quantitiesto meet thelimitsof the layer displacement, the location isrelatively flexible. Seismic wall for continuous layout,full-length through.Should bedesigned to avoid the wall mutations in limb length and alignment is notupand down the hole. The sametime.The inside of the hole marginscolumnshould not belessthan300mm inordertoguaranteethelengthof the column as the edgeof the component and constraint edgecomponents.Thebi-direc tional lateral force resisting structural form of vertical andhorizontalwallconnected.Each other as the affinityof the shear wall. For one, two seismic frame she ar walls,even beam highratio should notgreaterthan 5 and a height of not less than400mm.Midline columnand beams,wall midline shouldnotbe greater tha nthe columnwidthof1/4,in order toreduce thetorsional effect of the seismicaction onthecolumn.Otherwisecan be taken tostrengthen thestirrupratio inthe column tomake up.If theshear wall shearspan thanthe big two. Eventhe beamcro ss-height ratiogreaterthan 2.5, then the design pressure of thecut shouldnotmakeabig 0.2. However, if the shearwallshear spanratioof less than two couplingbeams span of less than 2.5, then the shear compres sion ratiois notgreater than 0.15. Theother hand,the bottom ofthe frame shear wallstructure to enhance thedesign should notbe less than200mmand notlessthanstorey 1/16,otherpartsshouldnot be less than 160mm and not less thanstorey 1/20. Aroundthe wall of the frame shear wall structure shouldbe set to the beam or dark beamand the side columntoform a border. Horizontal distributionofshear walls can from the shear effect,this design when building higher longeror framestructure reinforcement should be appropriatelyincreased, especially in the sensitiveparts of the beam position or temperature, stiffnesschange is bestappropriately increased, thenconsideration shouldbe givento the wallverticalreinforcement,because it is mainly from the bending effect, andtake in some multi-storeyshearwall structurereinforcedreinforcement rate -likelessconstrained edgeofthecomponent or components reinforcement of theedge component.References: [1 sad Hayashi,He Yaming. On the shortshear wall high-rise buildingdesign [J].Keyuan, 2008, (O2).高层框架剪力墙结构设计吴继成摘要: 本文从框架剪力墙结构设计的基本概念人手, 分析了框架剪力墙的构造设计内容, 包括抗震墙、剪跨比等的设计, 并出混凝土结构中最常用的框架剪力墙结构设计的注意要点。

毕业设计(论文)外文资料翻译(学生用)

毕业设计(论文)外文资料翻译(学生用)

毕业设计外文资料翻译学院:信息科学与工程学院专业:软件工程姓名: XXXXX学号: XXXXXXXXX外文出处: Think In Java (用外文写)附件: 1.外文资料翻译译文;2.外文原文。

附件1:外文资料翻译译文网络编程历史上的网络编程都倾向于困难、复杂,而且极易出错。

程序员必须掌握与网络有关的大量细节,有时甚至要对硬件有深刻的认识。

一般地,我们需要理解连网协议中不同的“层”(Layer)。

而且对于每个连网库,一般都包含了数量众多的函数,分别涉及信息块的连接、打包和拆包;这些块的来回运输;以及握手等等。

这是一项令人痛苦的工作。

但是,连网本身的概念并不是很难。

我们想获得位于其他地方某台机器上的信息,并把它们移到这儿;或者相反。

这与读写文件非常相似,只是文件存在于远程机器上,而且远程机器有权决定如何处理我们请求或者发送的数据。

Java最出色的一个地方就是它的“无痛苦连网”概念。

有关连网的基层细节已被尽可能地提取出去,并隐藏在JVM以及Java的本机安装系统里进行控制。

我们使用的编程模型是一个文件的模型;事实上,网络连接(一个“套接字”)已被封装到系统对象里,所以可象对其他数据流那样采用同样的方法调用。

除此以外,在我们处理另一个连网问题——同时控制多个网络连接——的时候,Java内建的多线程机制也是十分方便的。

本章将用一系列易懂的例子解释Java的连网支持。

15.1 机器的标识当然,为了分辨来自别处的一台机器,以及为了保证自己连接的是希望的那台机器,必须有一种机制能独一无二地标识出网络内的每台机器。

早期网络只解决了如何在本地网络环境中为机器提供唯一的名字。

但Java面向的是整个因特网,这要求用一种机制对来自世界各地的机器进行标识。

为达到这个目的,我们采用了IP(互联网地址)的概念。

IP以两种形式存在着:(1) 大家最熟悉的DNS(域名服务)形式。

我自己的域名是。

所以假定我在自己的域内有一台名为Opus的计算机,它的域名就可以是。

毕 业 设 计(英文翻译)

毕 业 设 计(英文翻译)

附录G:英文翻译参考(要求学生完成与论文有关的外文资料中文字数5000字左右的英译汉,旨在培养学生利用外文资料开展研究工作的能力,为所选课题提供前沿参考资料。

)毕业设计(英文翻译)题目系别:专业:班级:学生姓名:学号:指导教师:一位从事质量管理的人约瑟夫·朱兰出生于圣诞夜,1904 在罗马尼亚的喀尔巴阡山脉山中。

他青年时期的村庄中贫穷、迷信和反犹太主义甚是猖獗。

1912年朱兰家搬到了明尼阿波尼斯州,虽然充满了危险,但是它却让一个男孩充满信心和希望。

从如此多了一个在质量观念的世界最好改革者之一。

在他90年的生活中,朱兰一直是一个精力充沛的思想者倡导者,推动着传统的质量思想向前走。

因为九岁就被雇用,朱兰表示在他的生活工作上永不停止。

记者:技术方面如何讲质量?朱兰:技术有不同方面:一、当然是精密。

物的对精密的需求像电子学、化学…我们看来它们似乎需要放大来说,和重要的原子尘的有关于质量。

要做到高精密具有相当大的挑战,而且我们已经遇见非常大的挑战。

另外的一个方面是可信度-没有失败。

当我们举例来说建立一个系统,同类空中交通管制的时候,我们不想要它失败。

我们必须把可信度建入系统。

因为我们投入很大的资金并依赖这些系统,系统非常复杂,这是逐渐增加的。

除此之外,有对公司的失败费用。

如果事物在领域中意外失败,可以说,它影响民众。

但是如果他们失败在内部,然后它影响公司的费用,而且已经试着发现这些费用在哪里和该如何免除他们。

因此那些是相当大的因素:精密、可信度和费用。

还有其它的,当然,但是我认为这些是主要的一些。

记者:据说是质量有在美国变成一种产业的可能?朱兰:资讯科技当然有。

已经有大的变化。

在世纪中初期当质量的一个想法到一个检验部门的时候,这有了分开的工作,东西被做坏之后。

检验是相当易错的程序,实际上。

而且无论如何,资讯科技在那天中相当花时间,直到某事已经被认为是否资讯科技是正确的。

应该强调计划,如此它不被错误首先订定。

毕业设计英文翻译

毕业设计英文翻译

附录:英文翻译附录Ⅰ:英文翻译Fig.6.64.Gearbox diagram and gearshift pattern of a conventional6-speed automaticgearbox(ZF),production design Figure12.48In fourth(direct)gear,clutches A and B are closed and planetary gear set III rotatesas a block.Reversing the rotational direction in reverse gear is achieved bythe clutch C and the brake F.With a ratio ranging from3.43in first gear to 0.59insixth gear,the overall gear ratio of the transmission amounts to5.81[6.11–6.12,6.27,6.47].6.7.5Commercial Vehicle Hybrid DrivesSerial hybrid powertrains have a practical relevance for commercial vehicles.They have no mechanical coupling of the engine to the wheels(see Section 3.2.4).The serial hybrid drive has the advantage of being highly flexible in terms of theselection of an electrical energy supply source.The following are possible:•Diesel generator set:This design exhibits the features of the serial hybridpowertrain described in Section3.2.4.An optional electrical energy accumulator(electrochemical battery or doublelayercapacitors)can be used in the intermediate voltage circuit between thegenerator and the traction motor(s).The energy storage unit can be used for intermediate storage of energy recuperated during braking or for carrying out purely electric vehicle operation without the combustion engine.•Fuel cell:In this case,the supply of electric power carried out by the traction motor(s)is taken over by a fuel cell(see Section3.2.3).A hybridisation with an additional battery is recommendable to ensure a system capable of recuperation.附录:英文翻译•Overhead contact line:The supply of electric power carried out by the tractionmotor(s)can also be taken over by an overhead contact system,e.g.for city busapplications.With such applications,a small diesel generator may be used to enable manoeuvring operation without recourse to the overhead contact system.Basic system components of a serial hybrid drive:•Generator:preferably a permanent-magnet three-phase synchronous motor (PSM)flanged to the diesel engine;a special design is the transversal fluxmotor(TFM).•Feed-in:rectifier for converting the three-phase current of the generator into direct current.•Intermediate voltage circuit:electrical energy supply for the tractionmotors.•Traction inverter:pulse-controlled traction inverter for controlling the threephaseAC traction motor with either ASM(asynchronous motor)or PSMdesign.•Control electronics:driving electronics and hybrid management.For all the drive configurations named,the electric traction motors can be arrangedas follows:•The central motor acting directly on a conventional axle drive;no ratiorange.Application:city buses(Figure6.65a).Possible alternative:design with tandemmotors and summarising gearbox(Figure6.65c).•The central motor acting on a conventional axle drive via a gearbox assemblyfor speed adjustment,preferably a planetary gearbox;fixed ratio.Application: city buses(Figure6.65b).Possible alternative:design with tandem motors withtwo planetary gearboxes and a summarising gearbox(Figure6.65d).•Single-wheel drive with traction motors in direct proximity to the drive wheels(wheel hub drive)as final drive with gearbox assemblies for speed adjustment, preferably planetary gearboxes,often with two-stage design with no ratiorange.Application:city buses,commercial vehicles,special-purpose vehicles (Figure6.65e).•“In-hull drive”:single-wheel drive with traction motors,e.g.mounted at the centre of the vehicle,which acts on the drive wheels via propeller shafts.Two-stage selector transmission possible(shifting when stationary or during operation,with or without powershifting).Application:special wheeled and tracked vehicles(Figure6.65f).附录:英文翻译Fig.6.65.Schematic design types for traction motor applications.a Direct central motor;b central motor with planetary gear set;c tandem motors with summarising gear;d tandem motors with planetary gear set and summarising gear;e wheel hub drive withplanetary gear set;f“in-hull drive”with selector gearboxFigure6.66shows the electric drive axle EE Drive1from ZF.A wheel hubdrivewas designed for applications in city buses which can be used for all three of theabovementioned configurations with electric drive:serial hybrid powertrain withdiesel generator set,fuel cell drive and electric drive with a connection to an overheadcontact system.The following will focus on the EE Drive1serial hybriddrive design.The diesel generator set serves as a pure power source.Because there is no mechanicalcoupling,the engine torque does not act directly on the wheels.The electric drive is only responsible for vehicle motion and can principally execute the functions of driving and braking by reversing the direction of the energy flow. Inthe case of braking,kinetic energy of the vehicle can be fed back by means of the附录:英文翻译generator activity of the traction motor to the traction battery via the intermediatedirect current circuit(recuperation).Additionally,the motor activity of the generatoragainst the compression work done by the combustion engine can eliminate excess braking energy without wear.Finally,the electric energy from the intermediatedirect current circuit can be converted via a brake resistor into heat(wearfree permanent brake).In the schematic diagram of the wheel hub drive in Figure6.66,one electric motor mounted concentrically with the wheel axis acts per driven axle on the leftwheel and one on the right wheel,respectively,via a two-stage planetary gearbox.The drive for each of which is though the sun gear and the output via the spider.Both ring gears are fixed to the housing(see Section6.8.4“Hub Drives for CommercialVehicles”).6.7.6Continuously Variable Commercial Vehicle Transmissions(CVT)Mechanical continuously variable transmissions are currently not in prospect forcommercial vehicles.Pulley transmissions as used in passenger cars(up to 350Nm)have neither the necessary torque capacity nor the necessaryrobustnessfor use in commercial vehicles.There are test vehicles with toroidal variators (friction gear)which have higher torque capacity than chain converters. Especiallywith agricultural machines and mobile work machines,however,continuously variable hydrostatic transmissions in combination with geared transmissions representa sensible and thus widespread form of drive.While continuously variable hydrostatic transmissions boast a simple, comfortableoperation and high automatability,their overall level of efficiency is moderate at best[6.36].Purely hydrostatic continuously variable transmissions never became a popular附录:英文翻译choice for drives with a large overall gear ratio which transmit the total installedengine power and/or have high transport shares,as e.g.in agricultural tractors. Instead,tractors are increasingly being fitted with continuously variable transmissions based on hydrostatic power-splitting[6.14].In continuously variable transmissions with hydrostatic power-split,the drive power of the engine is split into a mechanical branch and a hydrostatic branch andthen combined again.The continuous ratio change is a result of the altered specificdisplacement volume of the hydrostatic displacement machine.Transmission designswork predominately with adjustment of the hydrostatic pump(primary adjustment).The hydrostatic power fraction is concept-dependent and can reach upto100%of the input power;even areas of operation with reactive power flow areused.Figure6.67shows the two most important basic designs of drives with hydrostaticpower-split.In Figure6.67a,the power is split with a constant speed ratioand recombined in a planetary gear with a constant torque ratio.In Figure 6.67b,the exact reverse is the case.Depending on the basic design and the way theconnectionshafts of the planetary gearbox are connected,the hydrostatic power fraction takes different paths over the total ratio[6.37].The transmission system shown in Figure6.68is a continuously adjustable hydrostatictransmission with power-split.It consists of the following components:planetary coupled gear,hydrostatic unit,reversing gear,electrohydraulic control,sensor system and electronic control unit.The total ratio of the transmission canbe continuously adjusted within a range of∞to+/–0.58.This overall range is subdivided into four fixed transmission ranges which are adjusted via the planetary gearbox and are each transmitted again with the constantgear of the countershaft reversing gear.The planetary gearbox consists offour planetary gears.The front differential drive is designed as a three-stage coupledgear with five shafts(planetary gears P1,P2,P3).附录:英文翻译Among the five shafts are two input shafts,the engine-speed dependent gearboxinput shaft and the continuously variable hydrostatic input shaft,and three outputshafts which can be connected to the fourth planetary gear set P4via the clutchesC1,C2and C3.The fourth planetary gear set P4has the function of a range unit actingas reduction step in the first two transmission ranges1and2and rotates additionallyas a block in ranges3and4[6.34].A ratio range can be defined in each transmission range.Within the transmissionrange,the continuously variable ratio is merely dependent on the ratio of the hydrostatic input speed n2to the gearbox input speed n1and on the rotational directionof the hydrostatic input shaft n2with respect to the constant rotational directionof the gearbox input shaft n1.The speed ratio n2/n1can have any value between+1and–1in every transmission range.The final ratio at the end of every transmission range is equal to the initial ratioof the transmission range which follows.Thus no speed difference arises in the respectiveshifting elements during the automatic shifting without power interruption.The drive power is power-split forwards and backwards in all transmissionranges and transmitted through the hydrostatic unit and through the planetary gearset.There is a ratio in every range in which the hydrostatic power becomes zero(n2=0).In this state,the drive power is transmitted on a purely mechanical basis.The gearbox efficiency achieves its respective maximum value in this附录:英文翻译position.6.8Final DrivesFigure4.2shows a hierarchical classification of individual ratios in the powertrain.Figure6.69shows the components derived from this classification whichfall under the category“final drive”:•axle drive,•differential gear,locking differential,•hub drive(commercial vehicles)and•transfer gearbox(in case of multiple driven axles).The different final drive designs result from the position of the engine relative tothe direction of travel,the position of the engine relative to the transmission, andthe ratio allocation between the transmission,transfer box,axle drive and hub drive.Because of the major differences in the final drive designs,a distinction ismade below between passenger cars and commercial vehicles.Examples of themost important production designs are shown in Section12.3“Final drives”.6.8.1Axle Drives for Passenger CarsThe basic axle drive designs shown in Figure6.70can be derived from the numerouspossible configurations of assemblies in the powertrain:•spur gear axle drive,•bevel gear axle drive of helical bevel or hypoid design and•worm gear axle drive.Other options for the final transmission are belt drives(DAF Variomatic)and chain drives(motorcycles).1/Spur Gear Axle DriveSpur gear axle drives are now common because of the popularity of vehicles附录:英文翻译withtransverse front-mounted engines.The axle drive is driven either directly by theoutput shaft of the transmission,or by idler gears.It is normally favourable for thedifferential cage drive if the engine and transmission are mounted side by side, with the disadvantage of having drive shafts of unequal length to the wheels. Thereasons for their popularity are the compactness and low production cost of spurgears,normally helical cut.There are also maintenance advantages in combiningtransmission and axle drive,since in most cases the lubrication system is the same.2/Bevel Gear Axle DriveIn powertrains where the engine is longitudinally mounted,and in all-wheel drives,the power flow to the wheels has to be turned through90°.A bevel gearaxle drive is one of a wide variety of means of achieving this.The axle drive canbe integrated in the transmission housing(transaxle design),or designed as an independentassembly,as in vehicles with standard drive.Fig.6.70.In the case of bevel gear axle drives a distinction can also be made between helicalbevel drive and hypoid drive,according to the engagement of bevel gear and crown gear(Figure6.70).In passenger cars,hypoid drives are usually used,in which the bevel drive pinion engages below the axial centre of the crown gear.This offset makes the diameter of the bevel drive pinion larger,and the crown gearcan be smaller for the same load than in helical bevel drives in which the axes intersect.The sliding friction between the tooth flanks,which contributes substantially to reducing noise,creates very high surface pressure forces which demandpressure-resistant oil(hypoid oil)to lubricate the axle drive(see also Section 11.2附录:英文翻译“Lubrication of Gearboxes,Gearbox Lubricants”).The offset also enables the propeller shaft to be mounted lower,reducing the size of the transmission tunnel.3/Worm Gear Axle DriveThere are now no more axle drives with worm gear axle drive in production. Thistype of drive was used in some Peugeot models in the1970s.They are now rarelyused,mainly because of the difficulty and expense of manufacturing the worm andthe worm gearwheel.But the worm gear axle drive does have significant advantages.It offers large multiplications in a compact space.The worm can be located below or above the worm gearwheel.The former case means a low centre of gravityand low-mounted propeller shaft,eliminating the obtrusive propeller shaft tunnel.Mounting the worm above the gearwheel gives the vehicle good ground clearance,a particular advantage for off-road vehicles.If worms are used in multi-axledrives,then a continuous propeller shaft coupled to the axles can be used. Wormgear drives are superior to all other types of drive as regards quiet running, becausemeshing is sliding,and there is always a film of oil between the frictionally engaged tooth flanks.Since there are large axial forces with worm gear drives, theworm bearing requires careful consideration.4/Transmission RatiosThe ratio of the powertrain i A in passenger cars is derived from the transmissionratio i G and the final ratio i E(see also Section4.1).In most passenger car transmissionsthe transmission ratio i G of the largest gear is fixed at i G≈0.7–1.0.The ratio of the powertrain i A is fixed by selecting the axle ratio i E,A to matchthe power,the desired maximum final speed etc.For individual passenger car axledrives the following ratios are typical:•spur gear axle drive i E=i E,A≈3.0–5.5,•bevel gear axle drive i E=i E,A≈2.5–5.0,•worm gear axle drive i E=i E,A≥5.0.The small ratios occur in powerful passenger cars and sports cars,whilst the largeratios occur in low-powered small passenger cars and all-wheel drive vehicles.The specification of the axle drives relates to the input torque available,i.e. theoutput torque of the transmission.附录:英文翻译5/Comparison of Different DesignsTable6.15provides a comparison of the main basic designs of passenger car axledrives:spur gear,bevel gear and worm gear axle drive.The comparison criteriaare quiet running,manufacturing cost,arrangement of bearings,lubrication, efficiency,service life,load capacity and space requirements.6.8.2Axle Drives for Commercial VehiclesIn commercial vehicles the axle drive can be of single-stage or multi-stage design.There are designs in which the ratio of the“axle”is split between the axledrive(i E,A)and the hub drive(i E,N).In this case,the term centre gearbox is used insteadof axle drive.The commercial vehicle final drive accommodates the axle drive bevel gears or the worm drive,the differential gear unit and,in the case of multistageaxle drives,spur gear sets or planetary sets and the drive-through to the next axle.As mentioned above,axle drives can be subdivided into single-stage and multi-stage axle drives.Some designs of axle dives are given in Section12.3.2.1/Single-Stage Axle DrivesDepending on the type of drive,the single-stage axle drive(Figure6.71)is dividedear drive;b double bevel gear drive;c worm gear drive•bevel gear drive,Figure6.71a,•double bevel gear drive(split bevel drive),Figure6.71b,and•worm gear drive,Figure6.71c.附录:英文翻译The spur gear axle drive is used only in commercial vehicles of up to3.5t grossweight rating,and will not be discussed further here.2/Multi-Stage Axle DrivesIn the case of multi-stage axle drives(Figure6.72)there are several designs:•countershaft,front-mounted,Figure6.72a1,•countershaft,top-mounted,Figure6.72a2,•two-speed with spur gear countershaft,Figure6.72c,•two-speed with planetary gear,Figure6.72d.6.车辆传动系:基本设计原则图6.63为变速箱结构简图以及5挡自动变速箱换挡模式图,适用于轻型卡车,运载工具,小型货车以及小型客车。

毕业设计英文翻译中英文对照版

毕业设计英文翻译中英文对照版

Feasibility assessment of a leading-edge-flutter wind power generator前缘颤振风力发电机的可行性评估Luca Caracoglia卢卡卡拉克格里亚Department of Civil and Environmental Engineering, Northeastern University, 400 Snell Engineering Center, 360 Huntington A venue, Boston, MA 02115, USA美国东北大学土木与环境工程斯内尔工程中心400,亨廷顿大道360,波士顿02115This study addresses the preliminary technical feasibility assessment of a mechanical apparatus for conversion of wind energy. 这项研究涉及的是风能转换的机械设备的初步技术可行性评估。

The proposed device, designated as ‘‘leading-edge-fl utter wind power generator’’, employs aeroelastic dynamic instability of a blade airfoil, torsionally rotating about its leading edge. 这种被推荐的定义为“前缘颤振风力发电机”的设备,采用的气动弹性动态不稳定叶片翼型,通过尖端旋转产生扭矩。

Although the exploitation of aeroelastic phenomena has been proposed by the research community for energy harvesting, this apparatus is compact, simple and marginally susceptible to turbulence and wake effects.虽然气动弹性现象的开发已经有研究界提出可以通过能量采集。

毕业设计论文外文文献翻译

毕业设计论文外文文献翻译

xxxx大学xxx学院毕业设计(论文)外文文献翻译系部xxxx专业xxxx学生姓名xxxx 学号xxxx指导教师xxxx 职称xxxx2013年3 月Introducing the Spring FrameworkThe Spring Framework: a popular open source application framework that addresses many of the issues outlined in this book. This chapter will introduce the basic ideas of Spring and dis-cuss the central “bean factory” lightweight Inversion-of-Control (IoC) container in detail.Spring makes it particularly easy to implement lightweight, yet extensible, J2EE archi-tectures. It provides an out-of-the-box implementation of the fundamental architectural building blocks we recommend. Spring provides a consistent way of structuring your applications, and provides numerous middle tier features that can make J2EE development significantly easier and more flexible than in traditional approaches.The basic motivations for Spring are:To address areas not well served by other frameworks. There are numerous good solutions to specific areas of J2EE infrastructure: web frameworks, persistence solutions, remoting tools, and so on. However, integrating these tools into a comprehensive architecture can involve significant effort, and can become a burden. Spring aims to provide an end-to-end solution, integrating spe-cialized frameworks into a coherent overall infrastructure. Spring also addresses some areas that other frameworks don’t. For example, few frameworks address generic transaction management, data access object implementation, and gluing all those things together into an application, while still allowing for best-of-breed choice in each area. Hence we term Spring an application framework, rather than a web framework, IoC or AOP framework, or even middle tier framework.To allow for easy adoption. A framework should be cleanly layered, allowing the use of indi-vidual features without imposing a whole worldview on the application. Many Spring features, such as the JDBC abstraction layer or Hibernate integration, can be used in a library style or as part of the Spring end-to-end solution.To deliver ease of use. As we’ve noted, J2EE out of the box is relatively hard to use to solve many common problems. A good infrastructure framework should make simple tasks simple to achieve, without forcing tradeoffs for future complex requirements (like distributed transactions) on the application developer. It should allow developers to leverage J2EE services such as JTA where appropriate, but to avoid dependence on them in cases when they are unnecessarily complex.To make it easier to apply best practices. Spring aims to reduce the cost of adhering to best practices such as programming to interfaces, rather than classes, almost to zero. However, it leaves the choice of architectural style to the developer.Non-invasiveness. Application objects should have minimal dependence on the framework. If leveraging a specific Spring feature, an object should depend only on that particular feature, whether by implementing a callback interface or using the framework as a class library. IoC and AOP are the key enabling technologies for avoiding framework dependence.Consistent configuration. A good infrastructure framework should keep application configuration flexible and consistent, avoiding the need for custom singletons and factories. A single style should be applicable to all configuration needs, from the middle tier to web controllers.Ease of testing. Testing either whole applications or individual application classes in unit tests should be as easy as possible. Replacing resources or application objects with mock objects should be straightforward.To allow for extensibility. Because Spring is itself based on interfaces, rather than classes, it is easy to extend or customize it. Many Spring components use strategy interfaces, allowing easy customization.A Layered Application FrameworkChapter 6 introduced the Spring Framework as a lightweight container, competing with IoC containers such as PicoContainer. While the Spring lightweight container for JavaBeans is a core concept, this is just the foundation for a solution for all middleware layers.Basic Building Blockspring is a full-featured application framework that can be leveraged at many levels. It consists of multi-ple sub-frameworks that are fairly independent but still integrate closely into a one-stop shop, if desired. The key areas are:Bean factory. The Spring lightweight IoC container, capable of configuring and wiring up Java-Beans and most plain Java objects, removing the need for custom singletons and ad hoc configura-tion. Various out-of-the-box implementations include an XML-based bean factory. The lightweight IoC container and its Dependency Injection capabilities will be the main focus of this chapter.Application context. A Spring application context extends the bean factory concept by adding support for message sources and resource loading, and providing hooks into existing environ-ments. Various out-of-the-box implementations include standalone application contexts and an XML-based web application context.AOP framework. The Spring AOP framework provides AOP support for method interception on any class managed by a Spring lightweight container.It supports easy proxying of beans in a bean factory, seamlessly weaving in interceptors and other advice at runtime. Chapter 8 dis-cusses the Spring AOP framework in detail. The main use of the Spring AOP framework is to provide declarative enterprise services for POJOs.Auto-proxying. Spring provides a higher level of abstraction over the AOP framework and low-level services, which offers similar ease-of-use to .NET within a J2EE context. In particular, the provision of declarative enterprise services can be driven by source-level metadata.Transaction management. Spring provides a generic transaction management infrastructure, with pluggable transaction strategies (such as JTA and JDBC) and various means for demarcat-ing transactions in applications. Chapter 9 discusses its rationale and the power and flexibility that it offers.DAO abstraction. Spring defines a set of generic data access exceptions that can be used for cre-ating generic DAO interfaces that throw meaningful exceptions independent of the underlying persistence mechanism. Chapter 10 illustrates the Spring support for DAOs in more detail, examining JDBC, JDO, and Hibernate as implementation strategies.JDBC support. Spring offers two levels of JDBC abstraction that significantly ease the effort of writing JDBC-based DAOs: the org.springframework.jdbc.core package (a template/callback approach) and the org.springframework.jdbc.object package (modeling RDBMS operations as reusable objects). Using the Spring JDBC packages can deliver much greater pro-ductivity and eliminate the potential for common errors such as leaked connections, compared with direct use of JDBC. The Spring JDBC abstraction integrates with the transaction and DAO abstractions.Integration with O/R mapping tools. Spring provides support classesfor O/R Mapping tools like Hibernate, JDO, and iBATIS Database Layer to simplify resource setup, acquisition, and release, and to integrate with the overall transaction and DAO abstractions. These integration packages allow applications to dispense with custom ThreadLocal sessions and native transac-tion handling, regardless of the underlying O/R mapping approach they work with.Web MVC framework. Spring provides a clean implementation of web MVC, consistent with the JavaBean configuration approach. The Spring web framework enables web controllers to be configured within an IoC container, eliminating the need to write any custom code to access business layer services. It provides a generic DispatcherServlet and out-of-the-box controller classes for command and form handling. Request-to-controller mapping, view resolution, locale resolution and other important services are all pluggable, making the framework highly extensi-ble. The web framework is designed to work not only with JSP, but with any view technology, such as Velocity—without the need for additional bridges. Chapter 13 discusses web tier design and the Spring web MVC framework in detail.Remoting support. Spring provides a thin abstraction layer for accessing remote services without hard-coded lookups, and for exposing Spring-managed application beans as remote services. Out-of-the-box support is inc luded for RMI, Caucho’s Hessian and Burlap web service protocols, and WSDL Web Services via JAX-RPC. Chapter 11 discusses lightweight remoting.While Spring addresses areas as diverse as transaction management and web MVC, it uses a consistent approach everywhere. Once you have learned the basic configuration style, you will be able to apply it in many areas. Resources, middle tier objects, and web components are all set up using the same bean configuration mechanism. You can combine your entireconfiguration in one single bean definition file or split it by application modules or layers; the choice is up to you as the application developer. There is no need for diverse configuration files in a variety of formats, spread out across the application.Spring on J2EEAlthough many parts of Spring can be used in any kind of Java environment, it is primarily a J2EE application framework. For example, there are convenience classes for linking JNDI resources into a bean factory, such as JDBC DataSources and EJBs, and integration with JTA for distributed transaction management. In most cases, application objects do not need to work with J2EE APIs directly, improving reusability and meaning that there is no need to write verbose, hard-to-test, JNDI lookups.Thus Spring allows application code to seamlessly integrate into a J2EE environment without being unnecessarily tied to it. You can build upon J2EE services where it makes sense for your application, and choose lighter-weight solutions if there are no complex requirements. For example, you need to use JTA as transaction strategy only if you face distributed transaction requirements. For a single database, there are alternative strategies that do not depend on a J2EE container. Switching between those transac-tion strategies is merely a matter of configuration; Spring’s consistent abstraction avoids any need to change application code.Spring offers support for accessing EJBs. This is an important feature (and relevant even in a book on “J2EE without EJB”) because the u se of dynamic proxies as codeless client-side business delegates means that Spring can make using a local stateless session EJB an implementation-level, rather than a fundamen-tal architectural, choice.Thus if you want to use EJB, you can within a consistent architecture; however, you do not need to make EJB the cornerstone of your architecture. This Spring feature can make devel-oping EJB applications significantly faster, because there is no need to write custom code in service loca-tors or business delegates. Testing EJB client code is also much easier, because it only depends on the EJB’s Business Methods interface (which is not EJB-specific), not on JNDI or the EJB API.Spring also provides support for implementing EJBs, in the form of convenience superclasses for EJB implementation classes, which load a Spring lightweight container based on an environment variable specified in the ejb-jar.xml deployment descriptor. This is a powerful and convenient way of imple-menting SLSBs or MDBs that are facades for fine-grained POJOs: a best practice if you do choose to implement an EJB application. Using this Spring feature does not conflict with EJB in any way—it merely simplifies following good practice.Introducing the Spring FrameworkThe main aim of Spring is to make J2EE easier to use and promote good programming practice. It does not reinvent the wheel; thus you’ll find no logging packages in Spring, no connection pools, no distributed transaction coordinator. All these features are provided by other open source projects—such as Jakarta Commons Logging (which Spring uses for all its log output), Jakarta Commons DBCP (which can be used as local DataSource), and ObjectWeb JOTM (which can be used as transaction manager)—or by your J2EE application server. For the same reason, Spring doesn’t provide an O/R mapping layer: There are good solutions for this problem area, such as Hibernate and JDO.Spring does aim to make existing technologies easier to use. For example, although Spring is not in the business of low-level transactioncoordination, it does provide an abstraction layer over JTA or any other transaction strategy. Spring is also popular as middle tier infrastructure for Hibernate, because it provides solutions to many common issues like SessionFactory setup, ThreadLocal sessions, and exception handling. With the Spring HibernateTemplate class, implementation methods of Hibernate DAOs can be reduced to one-liners while properly participating in transactions.The Spring Framework does not aim to replace J2EE middle tier services as a whole. It is an application framework that makes accessing low-level J2EE container ser-vices easier. Furthermore, it offers lightweight alternatives for certain J2EE services in some scenarios, such as a JDBC-based transaction strategy instead of JTA when just working with a single database. Essentially, Spring enables you to write appli-cations that scale down as well as up.Spring for Web ApplicationsA typical usage of Spring in a J2EE environment is to serve as backbone for the logical middle tier of a J2EE web application. Spring provides a web application context concept, a powerful lightweight IoC container that seamlessly adapts to a web environment: It can be accessed from any kind of web tier, whether Struts, WebWork, Tapestry, JSF, Spring web MVC, or a custom solution.The following code shows a typical example of such a web application context. In a typical Spring web app, an applicationContext.xml file will reside in the WEB-INF directory, containing bean defini-tions according to the “spring-beans” DTD. In such a bean definition XML file, business objects and resources are defined, for example, a “myDataSource” bean, a “myInventoryManager” bean, and a “myProductManager” bean. Spring takes care of their configuration, their wiring up, and their lifecycle.<beans><bean id=”myDataSource” class=”org.springframework.jdbc. datasource.DriverManagerDataSource”><property name=”driverClassName”> <value>com.mysql.jdbc.Driver</value></property> <property name=”url”><value>jdbc:mysql:myds</value></property></bean><bean id=”myInventoryManager” class=”ebusiness.DefaultInventoryManager”> <property name=”dataSource”><ref bean=”myDataSource”/> </property></bean><bean id=”myProductManager” class=”ebusiness.DefaultProductManage r”><property name=”inventoryManager”><ref bean=”myInventoryManager”/> </property><property name=”retrieveCurrentStock”> <value>true</value></property></bean></beans>By default, all such beans have “singleton” scope: one instance per context. The “myInventoryManager” bean will automatically be wired up with the defined DataSource, while “myProductManager” will in turn receive a reference to the “myInventoryManager” bean. Those objects (traditionally called “beans” in Spring terminology) need to expos e only the corresponding bean properties or constructor arguments (as you’ll see later in this chapter); they do not have to perform any custom lookups.A root web application context will be loaded by a ContextLoaderListener that is defined in web.xml as follows:<web-app><listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class></listener>...</web-app>After initialization of the web app, the root web application context will be available as a ServletContext attribute to the whole web application, in the usual manner. It can be retrieved from there easily via fetching the corresponding attribute, or via a convenience method in org.springframework.web. context.support.WebApplicationContextUtils. This means that the application context will be available in any web resource with access to the ServletContext, like a Servlet, Filter, JSP, or Struts Action, as follows:WebApplicationContext wac = WebApplicationContextUtils.getWebApplicationContext(servletContext);The Spring web MVC framework allows web controllers to be defined as JavaBeans in child application contexts, one per dispatcher servlet. Such controllers can express dependencies on beans in the root application context via simple bean references. Therefore, typical Spring web MVC applications never need to perform a manual lookup of an application context or bean factory, or do any other form of lookup.Neither do other client objects that are managed by an application context themselves: They can receive collaborating objects as bean references.The Core Bean FactoryIn the previous section, we have seen a typical usage of the Spring IoC container in a web environment: The provided convenience classes allow for seamless integration without having to worry about low-level container details. Nevertheless, it does help to look at the inner workings to understand how Spring manages the container. Therefore, we will now look at the Spring bean container in more detail, starting at the lowest building block: the bean factory. Later, we’ll continue with resource setup and details on the application context concept.One of the main incentives for a lightweight container is to dispense with the multitude of custom facto-ries and singletons often found in J2EE applications. The Spring bean factory provides one consistent way to set up any number of application objects, whether coarse-grained components or fine-grained busi-ness objects. Applying reflection and Dependency Injection, the bean factory can host components that do not need to be aware of Spring at all. Hence we call Spring a non-invasive application framework.Fundamental InterfacesThe fundamental lightweight container interface is org.springframework.beans.factory.Bean Factory. This is a simple interface, which is easy to implement directly in the unlikely case that none of the implementations provided with Spring suffices. The BeanFactory interface offers two getBean() methods for looking up bean instances by String name, with the option to check for a required type (and throw an exception if there is a type mismatch).public interface BeanFactory {Object getBean(String name) throws BeansException;Object getBean(String name, Class requiredType) throws BeansException;boolean containsBean(String name);boolean isSingleton(String name) throws NoSuchBeanDefinitionException;String[] getAliases(String name) throws NoSuchBeanDefinitionException;}The isSingleton() method allows calling code to check whether the specified name represents a sin-gleton or prototype bean definition. In the case of a singleton bean, all calls to the getBean() method will return the same object instance. In the case of a prototype bean, each call to getBean() returns an inde-pendent object instance, configured identically.The getAliases() method will return alias names defined for the given bean name, if any. This mecha-nism is used to provide more descriptive alternative names for beans than are permitted in certain bean factory storage representations, such as XML id attributes.The methods in most BeanFactory implementations are aware of a hierarchy that the implementation may be part of. If a bean is not foundin the current factory, the parent factory will be asked, up until the root factory. From the point of view of a caller, all factories in such a hierarchy will appear to be merged into one. Bean definitions in ancestor contexts are visible to descendant contexts, but not the reverse.All exceptions thrown by the BeanFactory interface and sub-interfaces extend org.springframework. beans.BeansException, and are unchecked. This reflects the fact that low-level configuration prob-lems are not usually recoverable: Hence, application developers can choose to write code to recover from such failures if they wish to, but should not be forced to write code in the majority of cases where config-uration failure is fatal.Most implementations of the BeanFactory interface do not merely provide a registry of objects by name; they provide rich support for configuring those objects using IoC. For example, they manage dependen-cies between managed objects, as well as simple properties. In the next section, we’ll look at how such configuration can be expressed in a simple and intuitive XML structure.The sub-interface org.springframework.beans.factory.ListableBeanFactory supports listing beans in a factory. It provides methods to retrieve the number of beans defined, the names of all beans, and the names of beans that are instances of a given type:public interface ListableBeanFactory extends BeanFactory {int getBeanDefinitionCount();String[] getBeanDefinitionNames();String[] getBeanDefinitionNames(Class type);boolean containsBeanDefinition(String name);Map getBeansOfType(Class type, boolean includePrototypes,boolean includeFactoryBeans) throws BeansException}The ability to obtain such information about the objects managed by a ListableBeanFactory can be used to implement objects that work with a set of other objects known only at runtime.In contrast to the BeanFactory interface, the methods in ListableBeanFactory apply to the current factory instance and do not take account of a hierarchy that the factory may be part of. The org.spring framework.beans.factory.BeanFactoryUtils class provides analogous methods that traverse an entire factory hierarchy.There are various ways to leverage a Spring bean factory, ranging from simple bean configuration to J2EE resource integration and AOP proxy generation. The bean factory is the central, consistent way of setting up any kind of application objects in Spring, whether DAOs, business objects, or web controllers. Note that application objects seldom need to work with the BeanFactory interface directly, but are usu-ally configured and wired by a factory without the need for any Spring-specific code.For standalone usage, the Spring distribution provides a tiny spring-core.jar file that can be embed-ded in any kind of application. Its only third-party dependency beyond J2SE 1.3 (plus JAXP for XML parsing) is the Jakarta Commons Logging API.The bean factory is the core of Spring and the foundation for many other services that the framework offers. Nevertheless, the bean factory can easily be used stan-dalone if no other Spring services are required.Derivative:networkSpring 框架简介Spring框架:这是一个流行的开源应用框架,它可以解决很多问题。

本科毕业设计翻译英文

本科毕业设计翻译英文

( 1. Faculty of Civil Engineering & Geosciences, Delft University of Technology , P. O. Box 5048,2600 GA Delft, t he Nether lands; 2. Key Laboratory of Silicate Materials Science and Engineering of the Ministry of Education, Wuhan University of Technology, Wuhan 430070, China)Abstract: Coal tar, a by- product from the destructive distillation of coal in co king oven, is widely used in road engineering for its excellent adhesion and fuel resistance properties, especially for pavement surface treatments in gas stations and airports.However, coal tar has a high Poly cyclic Aromatic Hydro carbons ( or PAHs) content, which makes it toxic.I n 1985, the International Agency for Research on Cancer ( IARC) has proved that coal tar is carcinogenic to humans. Research showed that Coal Tar- based Sealers ( CTS) contribute to the majority of PAHs pollution in the water environment. Because of this environmental concern, CT S are not allowed in many dev eloped countries in the USA and Europe. In contrast, coal tar is still used for road engineering in China and is even used increasingly .This paper gives a literature review on the general information and research about environmental concern of using coal tar in road engineering. Based on the review , some possible alternatives to replace coal tar are described. These alternatives include nanoclay/ epoxy modified bitumen/ bitumen emulsion and waterborne polyuret hane/ epoxy resin, which are environmental friendly. They have the potential to perform as w ell as CTS, and even better in some special applications.Key words:coal tar; pavement surface treatment; adhesion property; poly cyclic aromatic hydrocarbons; modified bitumen emulsionCLC number: U 416 Document code: A Article ID: 1671- 4431( 2010) 17- 0001- 07Received date: 2010- 05- 07.Biography : Xiao Y( 1986- ) , Ph D Candidate. E-mail: yue. xiao@1 introductionTwo basic types of binders are currently used in the pavement surface treatment market: coal tar-based and bitumen-based. At some places like g as stat ions and airports, coal tar-based surface sealers performed much better than bitumen-based sealers with regards to adhesion properties and chemical resistance. Coal tar-based have better resistance to petroleum oils and inorganic acids, and have better moisture resistance[ Austin, 2005] .Because of these out standing properties, CTS are widely used in road engineering for pavement surfacetreatment for many years. However, coal tar is a complex hydrocarbon mixture consisting of hundred of PAH[SCHER, 2008] . These PAHs are toxic and considered human carcinogens. Because of it s environmental unfriendly properties, coal tar is not allowed in most of the developed counties like the Netherlands. In the Netherlands,use of tar containing product s is not allowed since 20 years, with one temporary except ion for antiskid runways in airfields [ van Leest , 2005] . But after 2010, it w ill not be allowed for airport pavement application anymore. Compared to these bans, coal tar is still used for road engineering in China. China Coal Tar Industry Report mentioned that the coal tar consumption w ill be on the upward t rend [CCTIR, 2008] .Based on new technologies like nano technology and two-component technology, other materials are developed for pavement surface treatment and they perform w ell. Modified bitumen emulsions, which can be applied at low temperatures, were successfully used in South Africa, Australia and many other countries. Additives such as polymers ( SBS, SBR and EVA ) , clays ( illite, kaolinite and montmorillonite ) are known to improve the properties of bitumen emulsions in special road applications [ TRB-EC102, 2006;Xiao, 2010] . With the waterborne two-component technology, coating manufacturers can producehigh-performance sealers and achieve the same or better properties than solvent-based sealers. Furthermore, waterborne resins for coating s usually do not contain or just contain a small amounts of other solvent s, indicating that waterborne two component systems are environmental friendly. Epoxy modified bitumen w as originally developed in the late 1950s by Shell Oil Company as a material designed to withstand fuel exposure [ Thom, 2006] . After full curing , epoxy modified bitumen mixture has high temperature stability and strength, excellent fatigue, superior adhesion and rutting resistance.In this paper, a short literature review is given on the use and properties of CTS for pavement surface treatment and its environmental concern. After that several possible alternatives are discussed, such as nanoclay modified bitumen emulsion, epoxy modified bitumen, waterborne polyurethane/ epoxy resin. These alternatives may have good properties and are environmental friendly.2 Use and Advantages of Coal Tar Based SealersCoal tar-based products are used in many industries, for example pavement engineering, the building industry and medical treatment s. In pavement engineering , one of the largest applications is CTS.Coal tar can be used as a binder and filler in surface treatment formulations, and as a modifier for epoxyresin surface coating s. T he streets of Baghdad w ere the first to be paved with tar from the 8th century AD. Tar was a vital component of the first sealed, or tarmac roads. The first tar macadam road with a tar-bound surface was placed in 1848 out side Nottingham, England. In Washington D. C. some of thetar-bound surface courses have a service life of about 30 years.Coal tar is a very complex mixture of chemicals. It s molecular structure is quite different from bitumen.Some of the constituents are described as PAHs. Being stable in molecular structure, these chemicals are incompatible with oil and gas, and provide a barrier coat to protect asphalt surfaces against the destructive effects of petroleum based products and chemicals [Aust in, 2005] . CTS have a better chemical resistance than bitumen based, extremely low permeability to moisture and a high resistance to ultraviolet radiation. These properties make it ideally suited for parking areas w here concentrations of oil and gasoline leaks are prevalent, like gas stations, truck and bus terminals and airport s. CTS are used to extend the life and reduce maintenance cost associated with asphalt pavements, primarily in asphalt road pavement. They are typically used at airports for aprons, taxiways and runways. The Federal Aviation Administration Advisory Circular 150/ 5370-10A Standards for Specifying Construction of Airports include a requirement for pavement sealers that they should contain at least 35% coal tar in runway asphalt pavement.The reason for this requirement is that CTS have a much better resistance to jet fuel than bitumen-based sealers [Austin, 2005].3 Environmental ConcernGenerally, coal tars consist of a mixture of many organic compounds, like benzene, toluene, phenol, naphthalene, anthracite , and others. The risk assessment of coal tar is largely based on PAHs, especially on Benzo (a) pyrene . PAHs are the most relevant component s in terms of toxicity in coal tarproducts[ SCHER, 2008] .3. 1 Polycyclic aromatic hydrocarbonsPolycyclic aromatic hydrocarbons are also known as polycyclic aromatic compounds, polyaromatic hydrocarbons or as polynuclear aromatics. PAHs are a group of over 100 different chemicals consisting of carbon and hydrogen in fused-ring structures. T able 1 shows several typical chemical structures of PAHs. PAHs are highly toxic and harmful to human and ecosystem health [Austin, 2005] . The content of PAHs in coal tar increases as the carbonization temperature increases.3.2 Environmental riskIn 1985, IARC has pointed out that coal tar pitches are carcinogenic in humans [IARC, 1985] . In 2008,three scientific commit tees ( SCCP, the Scientific Commit -tee on Consumer Products; SCHER, the Scientific Committee on Health and Environmental Risks; SCEN IHR, the Scientific Commit tee on Emerging and NewlyIdentified Health Risks) concluded that cancer risk was the most serious point of coal tar s risk characterizations [ SCHER, 2008] . Occupational exposure to coal tar increases the risk of developing skin cancer and other tissue sites , like lung, bladder, kidney and digestive tract . According to the IARC, products that include more than 5 percent of crude coal tar are Group 1 carcinogen which has sufficient evidence of carcinogenicity in humans. So, many countries all over the world have eliminated it s usage.In 2003, scientist s from the city of Austin ( USA ) identified CTS as a significant source of PAHs contamination. The United States Geological Survey and Austin City have conducted additional research that corroborates this finding, concluding that coal tar sealants are responsible for the majority of PAHs pollution in water environment in the Austin area. Coal tar-based pavement sealers are considered as a source of urban water pollution. These are long-lasting substances that can build up in the food chain to harmful levels to humans. Based on their investigations, Austin became the first city in the USA to ban the use of CTS for pavements [ Austin,2005; Mahler, 2005] .As a precaution, in Germany, manufacturers have voluntarily agreed to ban coal tar from their product s. In the Netherlands, coal tar containing products did not meet the Dutch Environmental Standards and w ill not be allowed for airport pavement after 2010.4 Possible AlternativesAccording to these environmental concerns, alternatives are required. These alternatives should have atleast comparable or better properties than CTS. At the same time, they should be environmental friendly. In this section, the possible use of modified bitumen emulsions, epoxy modified bitumen and waterborne resins are discussed.4. 1 Modified bitumen emulsionsBitumen emulsions are heterogeneous systems with two or more liquid phases, consisting of a continuous liquid phase ( water ) and at least one second liquid phase ( bitumen) dispersed in the former as fine droplets [ TRB-EC102, 2006] . Standard bitumen emulsions are normally considered to be of the oil in water type and contain from 40% to 75% bitumen, 0. 1% to 2. 5% emulsifier, 25% to 60% water plus some minor components. The bitumen droplets rang e from 0. 1 to 20 micron in diameter.4. 1. 1 Properties of modified bitumen emulsionsUnlike bitumen, bitumen emulsions do not need to be heated at high temperatures before application. Temperature storage and application at ambient temperature can avoid the use of energy and emissions associated with heating and drying [Kennedy, 1997]. This makes bitumen emulsions more economic and environmental friendl , compared to coal tar-based products.Additives are used to improve the properties of bitumen emulsions in special road applications. Polymer( SBS, SBR and EVA) , clay illite , kaolinite and montmorillonite and epoxy modified bitumen/ bitumen emulsions were successfully used in South Africa and Australia [ TRB-EC102, 2006; Xiao, 2010] .During the application of bitumen emulsion, the water must be separated from the bitumen phase and evaporate.This separation is called breaking. After complete evaporation of the water, the bitumen particles will coalesce and bond together to develop mechanical properties. This strength development is curing.4. 1.2 nanoclay modified bitumen emulsionThe most preferred and widely used nanoclays are organically modified smectite clays with a 2: 1-type layey structure such as montmorillonite, saponite, etc [ Ammala , 2007] . All these layered silicates have the same crystalline structure and normally have a thickness of about 1 nanometer and a length of about 50 ~ 1 000 nanometers.In nanoclay modified bitumen emulsion, three possible particle dispersions can be distinguished as Fig. 1 shows [Xiao, 2010]. In the case of type one (see Fig. 1( a) ) , all the nanoclay particles are dispersed in the bitumen droplets. In this case, after breaking and curing the particles are dispersed in the binder between the aggregates. In the second type (see Fig. 1( b) ) , all of the nanoclay particles are dispersed in the water phase. After breaking and full curing, the particles are surrounding at the boundaries of the bitumen droplet s. The third type( see Fig. 1( c) ) is a combination of the first two types. Some of the particles are dispersed in the bitumen droplets while the others are dispersed in the water phase. In this condition, after breaking and curing the nanoclay particles both occur in the binder and between the bitumen droplets.These dispersion types have a significant influence on the properties of bitumen residues. Further investigations need to be carried on for checking these dispersions.Fig . 2 shows the possible outstanding properties of nanoclay modified bitumen emulsion on outside chemical resistance [Xiao, 2010] . With the unmodified bitumen emulsion after curing on the pavement surface, fuel, moisture and ultraviolet radiation can affect the binder directly. These can decrease the performance and cause raveling and ageing problems. When nanoclay modified bitumen emulsions are used for surface treatment, four steps can be dist inguished during breaking and curing. First, nanoclay modified bitumen emulsion consist s mainly of water, bitumen drop and nanoclay layers. Second, the water phase evaporates during the breaking and curing process. Then, bitumen droplets adhere to nanoclay particles, causing clusters to form the binder. At the last, binder is formed with nanoclay layers inside.The dispersed nanoclay particles can decrease surface damages due to fuel, moisture, air, etc. to a certain extent, resulting in better chemical and ageing resistance.4.2 Epoxy modified bitumensThe epoxy modified bitumen binder is a two phase chemical system in which the continuous phase is an acid cured epoxy and the discontinuous phase is a mixture of specialized bitumens, which makes the mixture performdifferent from a traditional asphalt mixture.4. 2. 1 Properties of epoxy modified bitumensEpoxy modified bitumen was used for pavement treatment long time ago and has achieved better properties than unmodified bitumen. In 1967, it was used to strengthen the surface of San Francisco Bay smile-long San Mateo-Hay ward Bridge. After more than 40 years, the bridge surface is reported to be in excellent condition.The special structure of epoxy modified bitumen makes it perform different from traditional bitumen. It does not become brittle at low temperature and does not melt at high temperature. Epoxy modified bitumen is a flexible material that can be applied in thin surface layers. When used on roads, it sets quickly enough to allow early traffic even before full curing, which enables the road to be reopened withintwo hours [ Xiao, 2010] .Epoxy modified bitumen is reported to be extremely durable as w ell as flexible. Surfaces with epoxy modified bitumen obtained better skid resistance and produce less noise than bitumen based sealers. Epoxy modified bitumen has extremely high temperature stability and strength, superior rutting resistance, excellent adhesion properties, high resistance to surface abrasion and is sufficiently fuel resistance [ Elliot t, 2008; Xiao, 2010] .4.2.2 Two-component epoxy modifiedbitumenTwo-component epoxy modified bitumen is acold mix application material. It is a two componentreactive material based on two components. One is amix of bitumen, bitumen-compatible epoxides andadditives. The other one is a mix of hardeners. After mixing of these two component s, there will be a fast react ion leading to epoxy resin within a bitumen based matrix.The tensile strength of Esha Seal 2C, which is a kind of two-component epoxy modified bitumen, obtained from ICOPAL BV, was evaluated using the Direct T ensile Test . Fig. 3 shows the tensile strengthafter different curing times and temperatures.Results indicate that the curing rate of epoxy modified bitumen emulsion depends on the curing temperature. The tensile strength increases with increasing curing time temperature . The tensile strength after full curing is higher than thetensile strength of bitumen, which implies that roads can be reopened for traffic very quickly w hen epoxy modified bitumens are applied in the surface layer.4. 3 Waterborne resinsWaterborne resins use water as the main volatile liquid component . It always shows good adhesion and the resistance to fuel, water and chemical is good. New technologies in waterborne systems provide unique technical solutions to get good properties, such as good adhesion to concrete and acidic resistance. With the waterborne two-component technology, coating manufacturers can formulate high-performance coatings without a cosolvent and achieve the same or better properties. Here waterborne polyurethane and epoxy resins will be discussed.4. 3. 1 Waterborne polyurethane resinsPolyurethane is a polymer consisting of a chain of organic units joined by urethane carbamate links. Polyurethane resins are formed from the reaction of an isocyanate with compounds containing active hydrogen, as Fig.4 shows. When the two components are mixed the hydroxyl groups ( - OH) in the resin react with the isocyanate groups ( N=C=O) in the hardener and a three dimensional molecular structure is produced[Weiss, 1997] .Because only one isocyanate group can react with one hydroxyl group, it is possible to vary the ratio of hydroxyl groups and isocyanate groups slightly either w ay in order to modify the mechanical properties of the system.Basically, waterbornepolyurethanes can be described asreactive or non-reactive polymerscontaining urethane and urea groupswhich are stabilized in water byinternal or external emulsifiers. Thesedifferent hydrophilic modify cationsallow the production of stablewaterborne polyurethanes with average particle sizes between 10 nm and 200 nm. Waterborne polyurethane resin is a water-based aliphatic polyurethane emulsion.Waterborne polyurethanes are environmental friendly. They provide a tough, durable and highly flexible binder. The advantages associated with polyurethane coatings are their high tensile strength, excellent adhesion properties and chemical/ mechanical resistance. Properties of waterborne polyurethanes can be improved by adding modifiers, such as organoclay layers [ Kim, 2003; Xiao, 2010] .Addagrip 1000 System resin is a two-component polyurethane resin designed by Addagrip Surface Treatments UK Ltd. It can be used for sealing to protect asphalt surfaces from erosion caused by frostdamage, chemical at tack and aviation fuel spillage. Areas treated over the last twenty years at military and civil air fields have prevented further deterioration and increased the service life of the concrete pavement by an estimated 10~ 15 years. Table 2 show s the properties of the samples before and after surface treatment with Addagrip 1000 System resin. 10 cm x 10 cmx10 cm blocks w ere used. The sample surfaces w ere heated and dried by a hot compressedair system before the resin w as sprayed onto the surface [Addagrip Ltd. ] . After surface reatment with this kind of polyurethane resin, the water and fuel resistance can be improved significantly.4. 3. 2 Waterborne epoxy resinsEpoxy is a copolymer. It is formed from two different chemicals, the resin and the hardener. Most common epoxy resins are produced from a reaction between Epichlorhydrin and bispheno-l A, see Fig.5[Weiss,1997] .Waterborne epoxy resin, with excellent adhesion properties, is another possible alternative. Waterborne epoxy resin is a stable resin material prepared by dispersing epoxy resin in the form of particles or droplet s into the dispersion medium based on water as a continuous phase.Application ofwaterborne epoxy resinsis not onlyconvenient but alsocauses no pollution tothe environmentand no harm to thehuman body. Afteradding a properamount of curing/ solidifying agent, advantages like high strength ,high-temperature resistance, chemical resistance, fatigue resistance, and high antiaging ability can be achieved [ Xiao, 2010; Weiss, 1997]5 ConclusionCTS are widely used for pavement surface treatments because of their excellent adhesion properties and good fuel resistance. How ever, because of their high PAHs content s, which are considered as human carcinogens, CTS are not allowed anymore in some of the developed counties. In order to eliminate the significant threat of pollution to our environment, w e should stop using CTS. Instead, modified bitumen emulsions, epoxy modified bitumen, waterborne polyurethanes and waterborne epoxy resins could achievecomparable or better properties than CTS. All of them have good adhesion, excellent chemical and ageing resistance. Epoxy modified bitumen has extremely high temperature stability and strength. Application of waterborne resins is convenient and the curing rate can be easily adjusted by changing the ratio of chemical components. And, the most important, these alternatives are environmental friendly.AcknowledgementsThe scholarship from the China Scholarship Council is acknowledged. T he authors would like to express thanks to ICOPAL BV for their materials and technical supports.References[1] AddagripLtd.www .adda grip [2] Ammala A, Hill A J.Poly( M-Xylene Adipamide)-Kaolinite and Poly( M-XyleneAdipamide)-Montmorillonite Nanocomposites [J] . Journal of Applied Polymer Science, 2007(104):1377- 1381.[3] Austin. http: / /www .ci. austin. tx . us/ watershed/ coaltar- ban. htm. Austin Bans Use of Coal Tar Sealants-first in Nation,2005.[4] CCTIR.China Coal Tar Industry Report 2006-2010.[R],2008.[5] Elliott R. 2008. Epoxy Asphalt: Concept and Properties. Workshop of TRB 2008.[6] IARC. Polynuclear Aromatic 4 Bitumens , Coal Tars and Der ived Products,Shale Oils and Soots. IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Humans,Vol. 35. Lyon, France:International Agency for Research on Cancer,1985.[7] Kennedy J. Alter native Materials and Techniques for Road Pavement Construction[R] . London: DOE Energy Efficiency Office,1997.[8] Kim B K, Seo J W, Jeong H M. Morphology and Properties of Waterborne Polyurethane/ clay Nanocomposite [J]. European[9] SCHER. Scientific Committee on Health and Environmental Risks. Coal tar pitch, high temperature Human Health Part. CAS No: 65996- 93- 2. EINECS No: 266- 028-2.[10] Thom N H. Asphalt Cracking: A Nottingham Perspective [J].Engenaria Civil/ Civil Engineering, 2006(26) : 75- 84.[11] TRB-EC102. Asphalt Emulsion Technology. Transportation Research Board[S], 2006.[12] Van Leest A J, Gaar keuken G. The F O D. Resistance of Sur face Layers on Airfields in the Netherlands; in Situ and Laboratory Testing [R] . 2005 European Airport Pavement Workshop, 2005. [13] Van Metre P C, Mahler B J. Trends in Hydrophobic Organic Contaminants in Urban and Reference Lake Sediments Across the United States, 1970- 2001[J]. Environmental Science and Technology,2005, 39( 15) : 5567- 5574.[14] Weiss K D. Paint and Coatings: A Mature Industry in Transition [J].Progress in Polymer Science, 1997, 22(2):203- 245.[15] Xiao Y. Literature Review on Possible Alternatives to Tar for Antiskid Layers . Delft University o f Technology, Road and Railway Engineering Section[R] . Report No.7-10-185-1,the Nether lands.。

本科毕业设计(论文)外文翻译译文

本科毕业设计(论文)外文翻译译文

本科毕业设计(论文)外文翻译译文学生姓名:院(系):油气资源学院专业班级:物探0502指导教师:完成日期:年月日地震驱动评价与发展:以玻利维亚冲积盆地的研究为例起止页码:1099——1108出版日期:NOVEMBER 2005THE LEADING EDGE出版单位:PanYAmericanYEnergyvBuenosYAiresvYArgentinaJPYBLANGYvYBPYExplorationvYHoustonvYUSAJ.C.YCORDOVAandYE.YMARTINEZvYChacoYS.A.vYSantaYCruzvYBolivia 通过整合多种地球物理地质技术,在玻利维亚冲积盆地,我们可以减少许多与白垩纪储集层勘探有关的地质技术风险。

通过对这些远景区进行成功钻探我们可以验证我们的解释。

这些方法包括盆地模拟,联井及地震叠前同时反演,岩石性质及地震属性解释,A VO/A V A,水平地震同相轴,光谱分解。

联合解释能够得到构造和沉积模式的微笑校正。

迄今为止,在新区有七口井已经进行了成功钻探。

基质和区域地质。

Tarija/Chaco盆地的subandean 褶皱和冲断带山麓的中部和南部,部分扩展到玻利维亚的Boomerange地区经历了集中的成功的开采。

许多深大的泥盆纪气田已经被发现,目前正在生产。

另外在山麓发现的规模较小较浅的天然气和凝析气田和大的油田进行价格竞争,如果他们能产出较快的油流而且成本低。

最近发现气田就是这种情况。

接下来,我们赋予Aguja的虚假名字就是为了讲述这些油田的成功例子。

图1 Aguja油田位于玻利维亚中部Chaco盆地的西北角。

基底构造图显示了Isarzama背斜的相对位置。

地层柱状图显示了主要的储集层和源岩。

该油田在Trija和冲积盆地附近的益背斜基底上,该背斜将油田和Ben i盆地分开(图1),圈闭类型是上盘背斜,它存在于连续冲断层上,Aguja有两个主要结构:Aguja中部和Aguja Norte,通过重要的转换压缩断层将较早开发的“Sur”油田分开Yantata Centro结构是一个三路闭合对低角度逆冲断层并伴随有小的摆幅。

毕业设计英文 翻译(原文)

毕业设计英文 翻译(原文)

编号:毕业设计(论文)外文翻译(原文)院(系):桂林电子科技大学专业:电子信息工程学生姓名: xx学号: xxxxxxxxxxxxx 指导教师单位:桂林电子科技大学姓名: xxxx职称: xx2014年x月xx日Timing on and off power supplyusesThe switching power supply products are widely used in industrial automation and control, military equipment, scientific equipment, LED lighting, industrial equipment,communications equipment,electrical equipment,instrumentation, medical equipment, semiconductor cooling and heating, air purifiers, electronic refrigerator, LCD monitor, LED lighting, communications equipment, audio-visual products, security, computer chassis, digital products and equipment and other fields.IntroductionWith the rapid development of power electronics technology, power electronics equipment and people's work, the relationship of life become increasingly close, and electronic equipment without reliable power, into the 1980s, computer power and the full realization of the switching power supply, the first to complete the computer Power new generation to enter the switching power supply in the 1990s have entered into a variety of electronic, electrical devices, program-controlled switchboards, communications, electronic testing equipment power control equipment, power supply, etc. have been widely used in switching power supply, but also to promote the rapid development of the switching power supply technology .Switching power supply is the use of modern power electronics technology to control the ratio of the switching transistor to turn on and off to maintain a stable output voltage power supply, switching power supply is generally controlled by pulse width modulation (PWM) ICs and switching devices (MOSFET, BJT) composition. Switching power supply and linear power compared to both the cost and growth with the increase of output power, but the two different growth rates. A power point, linear power supply costs, but higher than the switching power supply. With the development of power electronics technology and innovation, making the switching power supply technology to continue to innovate, the turning points of this cost is increasingly move to the low output power side, the switching power supply provides a broad space for development.The direction of its development is the high-frequency switching power supply, high frequency switching power supply miniaturization, and switching power supply into a wider range of application areas, especially in high-tech fields, and promote the miniaturization of high-tech products, light of. In addition, the development and application of the switching power supply in terms of energy conservation, resource conservation and environmental protection are of great significance.classificationModern switching power supply, there are two: one is the DC switching power supply; the other is the AC switching power supply. Introduces only DC switching power supply and its function is poor power quality of the original eco-power (coarse) - such as mains power or battery power, converted to meet the equipment requirements of high-quality DC voltage (Varitronix) . The core of the DC switching power supply DC / DC converter. DC switching power supply classification is dependent on the classification of DC / DC converter. In other words, the classification of the classification of the DC switching power supply and DC/DC converter is the classification of essentially the same, the DC / DC converter is basically a classification of the DC switching power supply.DC /DC converter between the input and output electrical isolation can be divided into two categories: one is isolated called isolated DC/DC converter; the other is not isolated as non-isolated DC / DC converter.Isolated DC / DC converter can also be classified by the number of active power devices. The single tube of DC / DC converter Forward (Forward), Feedback (Feedback) two. The double-barreled double-barreled DC/ DC converter Forward (Double Transistor Forward Converter), twin-tube feedback (Double Transistor Feedback Converter), Push-Pull (Push the Pull Converter) and half-bridge (Half-Bridge Converter) four. Four DC / DC converter is the full-bridge DC / DC converter (Full-Bridge Converter).Non-isolated DC / DC converter, according to the number of active power devices can be divided into single-tube, double pipe, and four three categories. Single tube to a total of six of the DC / DC converter, step-down (Buck) DC / DC converter, step-up (Boost) DC / DC converters, DC / DC converter, boost buck (Buck Boost) device of Cuk the DC / DC converter, the Zeta DC / DC converter and SEPIC, the DC / DC converter. DC / DC converters, the Buck and Boost type DC / DC converter is the basic buck-boost of Cuk, Zeta, SEPIC, type DC / DC converter is derived from a single tube in this six. The twin-tube cascaded double-barreled boost (buck-boost) DC / DC converter DC / DC converter. Four DC / DC converter is used, the full-bridge DC / DC converter (Full-Bridge Converter).Isolated DC / DC converter input and output electrical isolation is usually transformer to achieve the function of the transformer has a transformer, so conducive to the expansion of the converter output range of applications, but also easy to achieve different voltage output , or a variety of the same voltage output.Power switch voltage and current rating, the converter's output power is usually proportional to the number of switch. The more the number of switch, the greater the output power of the DC / DC converter, four type than the two output power is twice as large,single-tube output power of only four 1/4.A combination of non-isolated converters and isolated converters can be a single converter does not have their own characteristics. Energy transmission points, one-way transmission and two-way transmission of two DC / DC converter. DC / DC converter with bi-directional transmission function, either side of the transmission power from the power of lateral load power from the load-lateral side of the transmission power.DC / DC converter can be divided into self-excited and separately controlled. With the positive feedback signal converter to switch to self-sustaining periodic switching converter, called self-excited converter, such as the the Luo Yeer (Royer,) converter is a typical push-pull self-oscillating converter. Controlled DC / DC converter switching device control signal is generated by specialized external control circuit.the switching power supply.People in the field of switching power supply technology side of the development of power electronic devices, while the development of the switching inverter technology, the two promote each other to promote the switching power supply annual growth rate of more than two digits toward the light, small, thin, low-noise, high reliability, the direction of development of anti-jamming. Switching power supply can be divided into AC / DC and DC / DC two categories, AC / AC DC / AC, such as inverters, DC / DC converter is now modular design technology and production processes at home and abroad have already matured and standardization, and has been recognized by the user, but AC / DC modular, its own characteristics make the modular process, encounter more complex technology and manufacturing process. Hereinafter to illustrate the structure and characteristics of the two types of switching power supply.Self-excited: no external signal source can be self-oscillation, completely self-excited to see it as feedback oscillation circuit of a transformer.Separate excitation: entirely dependent on external sustain oscillations, excited used widely in practical applications. According to the excitation signal structure classification; can be divided into pulse-width-modulated and pulse amplitude modulated two pulse width modulated control the width of the signal is frequency, pulse amplitude modulation control signal amplitude between the same effect are the oscillation frequency to maintain within a certain range to achieve the effect of voltage stability. The winding of the transformer can generally be divided into three types, one group is involved in the oscillation of the primary winding, a group of sustained oscillations in the feedback winding, there is a group of load winding. Such as Shanghai is used in household appliances art technological production of switching power supply, 220V AC bridge rectifier, changing to about 300V DC filter added tothe collector of the switch into the transformer for high frequency oscillation, the feedback winding feedback to the base to maintain the circuit oscillating load winding induction signal, the DC voltage by the rectifier, filter, regulator to provide power to the load. Load winding to provide power at the same time, take up the ability to voltage stability, the principle is the voltage output circuit connected to a voltage sampling device to monitor the output voltage changes, and timely feedback to the oscillator circuit to adjust the oscillation frequency, so as to achieve stable voltage purposes, in order to avoid the interference of the circuit, the feedback voltage back to the oscillator circuit with optocoupler isolation.technology developmentsThe high-frequency switching power supply is the direction of its development, high-frequency switching power supply miniaturization, and switching power supply into the broader field of application, especially in high-tech fields, and promote the development and advancement of the switching power supply, an annual more than two-digit growth rate toward the light, small, thin, low noise, high reliability, the direction of the anti-jamming. Switching power supply can be divided into AC / DC and DC / DC two categories, the DC / DC converter is now modular design technology and production processes at home and abroad have already matured and standardized, and has been recognized by the user, but modular AC / DC, because of its own characteristics makes the modular process, encounter more complex technology and manufacturing process. In addition, the development and application of the switching power supply in terms of energy conservation, resource conservation and environmental protection are of great significance.The switching power supply applications in power electronic devices as diodes, IGBT and MOSFET.SCR switching power supply input rectifier circuit and soft start circuit, a small amount of applications, the GTR drive difficult, low switching frequency, gradually replace the IGBT and MOSFET.Direction of development of the switching power supply is a high-frequency, high reliability, low power, low noise, jamming and modular. Small, thin, and the key technology is the high frequency switching power supply light, so foreign major switching power supply manufacturers have committed to synchronize the development of new intelligent components, in particular, is to improve the secondary rectifier loss, and the power of iron Oxygen materials to increase scientific and technological innovation in order to improve the magnetic properties of high frequency and large magnetic flux density (Bs), and capacitor miniaturization is a key technology. SMT technology allows the switching power supply has made considerable progress, the arrangement of the components in the circuit board on bothsides, to ensure that the light of the switching power supply, a small, thin. High-frequency switching power supply is bound to the traditional PWM switching technology innovation, realization of ZVS, ZCS soft-switching technology has become the mainstream technology of the switching power supply, and a substantial increase in the efficiency of the switching power supply. Indicators for high reliability, switching power supply manufacturers in the United States by reducing the operating current, reducing the junction temperature and other measures to reduce the stress of the device, greatly improve the reliability of products.Modularity is the overall trend of switching power supply, distributed power systems can be composed of modular power supply, can be designed to N +1 redundant power system, and the parallel capacity expansion. For this shortcoming of the switching power supply running noise, separate the pursuit of high frequency noise will also increase, while the use of part of the resonant converter circuit technology to achieve high frequency, in theory, but also reduce noise, but some The practical application of the resonant converter technology, there are still technical problems, it is still a lot of work in this field, so that the technology to be practical.Power electronics technology innovation, switching power supply industry has broad prospects for development. To accelerate the pace of development of the switching power supply industry in China, it must take the road of technological innovation, out of joint production and research development path with Chinese characteristics and contribute to the rapid development of China's national economy.Developments and trends of the switching power supply1955 U.S. Royer (Roger) invented the self-oscillating push-pull transistor single-transformer DC-DC converter is the beginning of the high-frequency conversion control circuit 1957 check race Jen, Sen, invented a self-oscillating push-pull dual transformers, 1964, U.S. scientists canceled frequency transformer in series the idea of switching power supply, the power supply to the size and weight of the decline in a fundamental way. 1969 increased due to the pressure of the high-power silicon transistor, diode reverse recovery time shortened and other components to improve, and finally made a 25-kHz switching power supply.At present, the switching power supply to the small, lightweight and high efficiency characteristics are widely used in a variety of computer-oriented terminal equipment, communications equipment, etc. Almost all electronic equipment is indispensable for a rapid development of today's electronic information industry power mode. Bipolar transistor made of 100kHz, 500kHz power MOS-FET made, though already the practical switching power supply is currently available on the market, but its frequency to be further improved. Toimprove the switching frequency, it is necessary to reduce the switching losses, and to reduce the switching losses, the need for high-speed switch components. However, the switching speed will be affected by the distribution of the charge stored in the inductance and capacitance, or diode circuit to produce a surge or noise. This will not only affect the surrounding electronic equipment, but also greatly reduce the reliability of the power supply itself. Which, in order to prevent the switching Kai - closed the voltage surge, RC or LC buffers can be used, and the current surge can be caused by the diode stored charge of amorphous and other core made of magnetic buffer . However, the high frequency more than 1MHz, the resonant circuit to make the switch on the voltage or current through the switch was a sine wave, which can reduce switching losses, but also to control the occurrence of surges. This switch is called the resonant switch. Of this switching power supply is active, you can, in theory, because in this way do not need to greatly improve the switching speed of the switching losses reduced to zero, and the noise is expected to become one of the high-frequency switching power supply The main ways. At present, many countries in the world are committed to several trillion Hz converter utility.the principle of IntroductionThe switching power supply of the process is quite easy to understand, linear power supplies, power transistors operating in the linear mode and linear power, the PWM switching power supply to the power transistor turns on and off state, in both states, on the power transistor V - security product is very small (conduction, low voltage, large current; shutdown, voltage, current) V oltammetric product / power device is power semiconductor devices on the loss.Compared with the linear power supply, the PWM switching power supply more efficient process is achieved by "chopping", that is cut into the amplitude of the input DC voltage equal to the input voltage amplitude of the pulse voltage. The pulse duty cycle is adjusted by the switching power supply controller. Once the input voltage is cut into the AC square wave, its amplitude through the transformer to raise or lower. Number of groups of output voltage can be increased by increasing the number of primary and secondary windings of the transformer. After the last AC waveform after the rectifier filter the DC output voltage.The main purpose of the controller is to maintain the stability of the output voltage, the course of their work is very similar to the linear form of the controller. That is the function blocks of the controller, the voltage reference and error amplifier can be designed the same as the linear regulator. Their difference lies in the error amplifier output (error voltage) in the drive before the power tube to go through a voltage / pulse-width conversion unit.Switching power supply There are two main ways of working: Forward transformand boost transformation. Although they are all part of the layout difference is small, but the course of their work vary greatly, have advantages in specific applications.the circuit schematicThe so-called switching power supply, as the name implies, is a door, a door power through a closed power to stop by, then what is the door, the switching power supply using SCR, some switch, these two component performance is similar, are relying on the base switch control pole (SCR), coupled with the pulse signal to complete the on and off, the pulse signal is half attentive to control the pole voltage increases, the switch or transistor conduction, the filter output voltage of 300V, 220V rectifier conduction, transmitted through the switching transformer secondary through the transformer to the voltage increase or decrease for each circuit work. Oscillation pulse of negative semi-attentive to the power regulator, base, or SCR control voltage lower than the original set voltage power regulator cut-off, 300V power is off, switch the transformer secondary no voltage, then each circuit The required operating voltage, depends on this secondary road rectifier filter capacitor discharge to maintain. Repeat the process until the next pulse cycle is a half weeks when the signal arrival. This switch transformer is called the high-frequency transformer, because the operating frequency is higher than the 50HZ low frequency. Then promote the pulse of the switch or SCR, which requires the oscillator circuit, we know, the transistor has a characteristic, is the base-emitter voltage is 0.65-0.7V is the zoom state, 0.7V These are the saturated hydraulic conductivity state-0.1V-0.3V in the oscillatory state, then the operating point after a good tune, to rely on the deep negative feedback to generate a negative pressure, so that the oscillating tube onset, the frequency of the oscillating tube capacitor charging and discharging of the length of time from the base to determine the oscillation frequency of the output pulse amplitude, and vice versa on the small, which determines the size of the output voltage of the power regulator. Transformer secondary output voltage regulator, usually switching transformer, single around a set of coils, the voltage at its upper end, as the reference voltage after the rectifier filter, then through the optocoupler, this benchmark voltage return to the base of the oscillating tube pole to adjust the level of the oscillation frequency, if the transformer secondary voltage is increased, the sampling coil output voltage increases, the positive feedback voltage obtained through the optocoupler is also increased, this voltage is applied oscillating tube base, so that oscillation frequency is reduced, played a stable secondary output voltage stability, too small do not have to go into detail, nor it is necessary to understand the fine, such a high-power voltage transformer by switching transmission, separated and after the class returned by sampling the voltage from the opto-coupler pass separated after class, so before the mains voltage, and after the classseparation, which is called cold plate, it is safe, transformers before power is independent, which is called switching power supply.the DC / DC conversionDC / DC converter is a fixed DC voltage transformation into a variable DC voltage, also known as the DC chopper. There are two ways of working chopper, one Ts constant pulse width modulation mode, change the ton (General), the second is the frequency modulation, the same ton to change the Ts, (easy to produce interference). Circuit by the following categories:Buck circuit - the step-down chopper, the average output voltage U0 is less than the input voltage Ui, the same polarity.Boost Circuit - step-up chopper, the average output voltage switching power supply schematic U0 is greater than the input voltage Ui, the same polarity.Buck-Boost circuit - buck or boost chopper, the output average voltage U0 is greater than or less than the input voltage Ui, the opposite polarity, the inductance transmission.Cuk circuit - a buck or boost chopper, the output average voltage U0 is greater than or less than the input voltage Ui, the opposite polarity, capacitance transmission.The above-mentioned non-isolated circuit, the isolation circuit forward circuits, feedback circuit, the half-bridge circuit, the full bridge circuit, push-pull circuit. Today's soft-switching technology makes a qualitative leap in the DC / DC the U.S. VICOR company design and manufacture a variety of ECI soft-switching DC / DC converter, the maximum output power 300W, 600W, 800W, etc., the corresponding power density (6.2 , 10,17) W/cm3 efficiency (80-90)%. A the Japanese Nemic Lambda latest using soft-switching technology, high frequency switching power supply module RM Series, its switching frequency (200 to 300) kHz, power density has reached 27W/cm3 with synchronous rectifier (MOSFETs instead of Schottky diodes ), so that the whole circuit efficiency by up to 90%.AC / DC conversionAC / DC conversion will transform AC to DC, the power flow can be bi-directional power flow by the power flow to load known as the "rectification", referred to as "active inverter power flow returned by the load power. AC / DC converter input 50/60Hz AC due must be rectified, filtered, so the volume is relatively large filter capacitor is essential, while experiencing safety standards (such as UL, CCEE, etc.) and EMC Directive restrictions (such as IEC, FCC, CSA) in the AC input side must be added to the EMC filter and use meets the safety standards of the components, thus limiting the miniaturization of the volume of AC / DC power, In addition, due to internal frequency, high voltage, current switching, making the problem difficult to solve EMC also high demands on the internal high-density mountingcircuit design, for the same reason, the high voltage, high current switch makes power supply loss increases, limiting the AC / DC converter modular process, and therefore must be used to power system optimal design method to make it work efficiency to reach a certain level of satisfaction.AC / DC conversion circuit wiring can be divided into half-wave circuit, full-wave circuit. Press the power phase can be divided into single-phase three-phase, multiphase. Can be divided into a quadrant, two quadrant, three quadrants, four-quadrant circuit work quadrant.he selection of the switching power supplySwitching power supply input on the anti-jamming performance, compared to its circuit structure characteristics (multi-level series), the input disturbances, such as surge voltage is difficult to pass on the stability of the output voltage of the technical indicators and linear power have greater advantages, the output voltage stability up to (0.5)%. Switching power supply module as an integrated power electronic devices should be selected。

毕业设计英文翻译

毕业设计英文翻译

沈阳工业大学化工装备学院毕业设计(论文)外文翻译毕业设计(论文)题目:含硫氨污水冷却器外文题目:Head processing technology译文题目:封头加工工艺院(系):化工装备学院专业班级:过控0802班学生姓名:孙鹏博指导教师:闫小波2012年3月11日Head processing technology1.welding process1.1welding operationOur factory common welding methods are: manual welding, argon arc welding, submerged arc welding.(1) manual welding is mainly used for carbon steel 3-6mm plate welding.(2) submerged arc welding to more than 8mm carbon steel stainless steel sheet welding mainly.(3)3-6mm stainless steel argon arc welding with welding mainly. Commonly used stainless steel wire ER304and ER316L steel wire, commonly used to J422and J507and J426and J427low-temperature welding consumables. Flux of carbon steel used is the HJ431, stainless steel commonly used is HJ260,.As a result of welding wire flux can be easily affected with damp, stored in the infrared drying machine, flux HJ431and HJ260drying temperature is 250-300℃. Welding wire J422and J350drying temperature were 150℃ and 300 ℃Welding process is completely in accordance with the" welding" execution, sheet thickness determines the welding to welding or double sided arc welding in welding, after the weld seam inspection ( RT X ray ) judgment without pores, cracks and other defects, such as found in the above deficiencies, to the repair, until the filming.1.2 welding operation standard(1) welding procedure card after receiving process, affirm the process card and physical material, quantity, unit number, specifications, size instruction number is consistent, whether there is debris around the wafer, wafer splashes whether clean removal, such as treatment is not clean, will use the grinding clean.(2) there is no welding test plate, groove cutting quality can meet the requirement, material surface without obvious defects, such as abnormal response.(3) according to the" Regulations" welding procedure card check of welding groove type and dimensions correspond to.(4) on each side of groove surface grinding, butt edge offset is not greater than the10% thickness, and not more than1.5mm.(5) point fixed the first weld layer terminal welding length not less than 50mm, arc board specifications should be 150*150mm and a mask having R arc, team rounds should be given within 8 hours of welding, or to use flame to the moisture inside the baking groove.(6) the welder holds" welding" and" welding records" for welding consumables, welding two class library for registration, using flux field volume should not exceed 4 hours, or to continue to back into the oven drying.(7) a, preheating plate thickness not less than 30mm carbon steel, low alloy steel, the preheating temperature of welding process by" card"," standard" provisions of the welding technology.B, preheating range width not less than 4mm and no less than 100mm. C, in the process of welding groove at any time temperature shall not be less than the prescribed temperature.D, when welding temperature is below 0 ℃( arbitrary thickness) must be heated to 15 ℃or above in order to welding.(8) a before welding, welding to welding equipment inspection, examination was normal before welding facilities.According to B,"" the requirements of welding process welding, welding and fill in the recordsC, welding, welding layers shall be in accordance with" welding" requirements, welding shall not be a large current, less layers. (9) removal of the root a, stainless steel cleaning before the root groove sides, within the range of 300mm, splashing paint coating.B, using carbon arc air gouging, should be selected according to the request carbon rod diameter.C, root cleaning, grinding cleaning groove and two side the existence of carburized layer, oxide, slag and other sundries. Grinding width: manual welding, rust, oxide above 20mm, oil30mm above, automatic welding, rust, grease, oxides 25mm50mm groove inner grinding requirements, carbon steel, low alloy steelδn ≤10mm weld, its two ends within the range of 300mm carburized layer must be completely removed, the rest part allows the removal of more than 50%. Other non-ferrous metals must be completely clear. [3]D, root cleaning, composite steel Cr-Mo, manual welding and the thicknessofδn ≥30mm welds shall be examined by PT.(10) during the process of welding defect repair by welding repair welding repair monitor instruction experienced welders as. Repair welding process should eliminate soldering phenomenon, or polished after welding, the following defects must be removed before welding to welding crack,①partial②③pits the stomaA shall not be lower than the parent material, weld.B, there shall be no undercutting.C, without removing the residual high seam. The surface shall not have cracks, pores, crater, undercut and slag inclusions, and may not retain the slag and spatter.D, removal of residual high weld inspection shall not have any defect display PT.E, such as the defects of carbon steel, low-alloy steel repair procedures: a grinding wheel or a carbon arc gouging polishing cleaning→ PT check grinder grinding out the welding groove, welding, PT, stainless steel repair procedures: a grinding wheel or a carbon arc gouging polishing cleaning→PT (δ n≥ 2mm need )→grinder polished to a welding groove welding→ PT examination. [4](12) welded internal rework, repair procedures: location of defect, defect removal→ PT→→removal check welding weld→ PT examination. [5] (13) according to RT film, RT staff and the welders in welding seam together determine the location of defects, including the following requirements when using UT to determine the defect position, the first repairδ n≥ 30mm use UT to determine the location of defects, two or three repairδ n≥ 20mm using UT to determine the defect position, UT positioning by RT after class. The position and depth of defect ( calibration side shall be the depth of defect≤1/2 side).(14) after the welding inspector or monitor by confirmed, in the process card signed your name and object together with transfer to the next process, by the next process responsibility recognition can.2.stamping process2.1stamping operationStamping operation is small head forming an important operation. The same stamping is also head of the cracking, thinning appeared most processsection.2.2punching machine.(1) the master cylinder is mainly used to connect the die head, is the head forming the necessary parts.(2) side cylinder used for pressing die ring, fixing the upper and lower mold ring of head disk. The head in the pressing process is to prevent the crease, as an important part of the drum kit.(3) the overflow valve used for controlling the compressor overall pressure, prevent the wafer during the pressing process of tears. (4) stamping valve in pressure, stamping valve on pressure relief, achieve average pressure effect.In addition, circuit boards, motors, circuit boards, storage tank, operation platform, pedestal are stamping machine components.2.3.3 stamping operation steps(1) first of all to undertake a blanking process card, find a good wafer.(2) the control process card on the technological requirements, put ona set of corresponding die, and with the use of gauges to determine the selected die size and to suppress the wafer size.(3) the wafer is clamped on the upper and lower mold inside the circle, and determine the die head of the center point and the center point of the wafer in a straight line.(4) the operation ring mold and die relative motion, pressure test, according to the control rod rebound to judge the size of the pressure, thereby regulating pressure size.(5) pressure test end, pressed wafer, stamping.2.3the stamping operation standard(1) the control task orders, confirm physical and process card is consistent, according to the process card confirming workpiece number, material, specification, batch number and other factors, at the same time check wafer end there is no crack, burr, polished wafer whether it meets the requirements, whether chamfer, is facing the good, there are special requirements when the problem is found, in time to contact.(2) according to the process card correct selection of die mold surface, inspection, found bruises and serious injury must be polished, but must be clean mold surface corrosion and dirt.(3) according to the technology card size, shape, texture, straight edge higher to suppress.(4) the warm-stamping ( according to requirement sheet property is heated to a certain temperature, and then stamping process ), to prepare a baking gun, gas, oxygen, percussion with head shall prepare the corresponding template, double-sided film to the wafer edge of both sides in a range of about 200-300mm template removal, and clear the film surface. [6] (5) mounted on the lower die, as the case to join the die pad, the wafer inside and outside surface coated with oil, applied range of top to200-300mm, smear should be uniform, the upper and lower mold are evenly coated.(6) the first gold stamping head, hanging out with a model head, check section shape, at the same time, check whether the drum kit, and there is no thinning, and check the surface has no scratch, hoop printing, such as none of the above abnormalities can continue to stamping, head forming, sealing surfaces such as scratches are timely grinding, and confirm the minimum board thickness, confirm whether a scratch, strain, curved peel, orange peel, drum kits, wrinkle, hoop printing etc..(7) such as a head drum kit fold phenomenon should be together with the card with the move to rework process technology.(8) each head should be able to see the instruction, piece number, material, or to transplantation, each product specifications after testing, the process card ( to sign the name ) together to the next process, by the next process validation.3.pressure drum process3.1pressure drum operationPressure drum process and stamping processes are the same steps in the process, stamping process range of φ 159- φ1900mm and pressure drum process is in the range of φ 1600- φ4800mm. And stamping is different pressure drum mostly the head generally forming, eventually forming is completed by spinning, stamping without the special requirements of customers, eventually forming step is not required. φ 1600- φ1900mm heads the two processes is needed.3.2pressure drum machine.(1) the main cylinder is provided with an upper die head is pressed drumexecution as long as part of.(2) supporting seat fixed lower die and upper die head center in a straight line.(3) supporting frame1is provided with a rolling wheel, a position adjusting before and after.(4) supporting frame is provided with a rolling wheel rotating disk II. In addition, there are hydraulic system, the motor, oil pump, oil tank, and a control console.3.3pressure drum machine operation steps(1) first of all to undertake a blanking process card, find a good wafer.(2) the control process card on the technological requirements, put ona set of corresponding die, and with the use of gauges to determine the selected die size and to suppress the wafer size.(3) and stamping machine is different from the original film is not pressure drum center began to suppress, but from the wafer edge, as long as the die and wafer alignment on the line.(4) the pressing process is continuously by controlling the rotation wheel is driven by the rotation of a wafer rotating, according to a certain order to suppress.(5) in after the pressing process, prepared template matching. If a deviation to make further adjustments.3.4pressure drum operation standard(1) die on the quality of the products and the smooth pressure drum forming crucial. Therefore, require that the operator must according to the processing situation of choice for mold and timely adjust shim plate.(2) the operator receives the process card, see process card, according to the process card check objects, to confirm the real instruction, one-piece, material. Number, batch number etc.. According to the choice of mold process card.(3) for EHA, EHB head shapes have adopted the 0.82*D standard selection, for DHB, PSH, MD and other special products according to technology card selection of mold, but in principle according to P*0.82/1.15or P*0.82/1.2 standard selection. [1](4) pressing carefully before inspection wafer quality, no seam wafer end is smooth, there is no gap, surface has no cutting slag and defects.(5) a weld in addition to carefully check the end of the wafer wafer defects, at the same time should be checked for weld seam is higher than that of base metal, weld ends of are welding spatter, weld end grinding smooth, there is no crack notch.(6) two or two or more superimposed when pressed, each slice of the joint surface should be clean, according to the circumstances must entrust welding class, the wafer is welded together to suppress.(7) detection of wafer thickness ( the thickest, most thin, whether and process card, measurement of wafer size and process card.(8) suppression must be removed before the inside and outside surface of all debris, to prevent pitting appeared.(9) for general stainless steel materials ( more than 5mm plate ) using Teflon plate mold and the lower mold dressing on surface polished smooth ( necessary nowadays mold to Teflon plate. ) to ensure the surface quality of the workpiece, while in the process of the pressing need to avoid debris into molds and semi-finished products. [6](10) the pressing process, when the wafer is a R shape, must use the corresponding R model measurement, the pressing process should be considered to adjust the pressure deformation degree.(11) pressing is finished, the measurement of plate thickness, measuring arc length. Check surface quality, check end and weld end is smooth ( necessary to polish out the ceremony ).(12) to check the semi-finished product with process card is on the move to the next process ( and sign the name ) by the next process to confirm acceptance before.4.spinning process4.1spinning operationThe spinning process is pressed after the drum head molding process, mainly for large head R and straight edge formation.4.2spinning machine.(1) forming wheel is connected to the corresponding mold, forming in the head inside, mold top with half formed head R and straight edge is tangent to tangent.(2) supporting wheel is also connected and molded wheel mold, forming in the head outside, and a forming wheel tangent.(3) base for fixing head, and the bottom according to head size before and after moving, the head should be installed so that the center of the base and the head of the center in a straight line.(4) the center rod is used for fixing head, and the center and the center of the base is in a straight line.In addition to the motor, a circuit board, is connected to the shaft, anda control console.4.3spinning procedure(1) to undertake pressure drum process card, according to the card to determine the corresponding head spinning.(2) according to the head of the diameter, select the corresponding upper and lower mold.(3) the clamping head, ensure that the head of the center point and the center of the base point in a straight line.(4) to adjust the molding wheel and the head of tangent, then according to the forming wheel position adjustment roller.(5) in the spinning process to observe the forming roller and the supporting roller relative position, and continue to use the template on the line alignment. Until the R reaches the requirements.4.4spinning operation standard(1) spinning wheel material for steel bearings or ductile iron, mold on the quality of the products and can spin forming closely related, therefore the operator must be processed according to choose suitable mold, at the same time, because of the shape of the mold and the surface condition of the quality of the workpiece has a great influence, therefore, before processing and machining process must on the mold for full inspection.(2) according to the process card requirements, confirm wafer, pressure drum or preload semi-finished instruction number, specifications, quantity of material, compliance, and check the quality of surface and end with no defect, abnormal timely and on the procedures of contact, and in a timely manner(3) check the semi-finished end is smooth, with or without notch, crack, surface has no cutting or welding slag, and shall inspect the weld seam is higher than that of base metal, weld ends whether spatter, weld end grinding smooth, there is no crack. [7](4) pressure drum or to the press after the finished product, must checkfor folding, cracking, crack is not conducive to the spinning processing defects.(5) for stainless steel workpiece, through to the pickling method of decontamination.(6) according to the process card selection of mold, general small arc r size requirements as a basis for selecting the internal wheel. (7) according to the different material, thickness of plate and sheet rebound, selection is slightly smaller than the internal wheel circular arc R.(8) for the special requirements of the product, according to its shape design inside the wheel, confirm the mold surface, good polishing processing.(9) spinning processing, in order to prevent scratching and improve the processing performance, suitable lubricant ( grease ) to prevent process heating head appears on the surface of hot cracks and scratches, can also prolong the service life of die.(10) the spinning process, should be considered a workpiece shaping and timely for pressure adjustment.(11) after the molding process, deal with the size, shape, thickness, surface quality inspections, confirmation.(12) molded product with the card with the transfer process to the next process ( in the process card signed their name ) by the procedures under the inspector or monitor check before.5.groove processThe 5.1groove Essentials(1) groove process is a head of the data ( including circumference, total height) to achieve JB/T4746 standard key process. [1](2) groove is in order and cylinder head connection time, make welding more thoroughly.(3) the main groove cutting process and cutting process tools, is the use of plasma cutting.(4) cutting, according to the card on the technological requirements, determine groove type ( inner groove, outside the mouth, X groove ) and determine the groove angle.(5) the groove before the head splashing agent applicator.(6) groove when the first test slope, then a protractor measuring angle, identified in the tolerance range, after adjustment, the whole slope. The 5.2groove operation standard(1) according to the process card to find real, order confirmation No., specification, material, batch number, quantity and check whether the workpiece has a drum kit, crack, delamination, wrinkle, and whether the loss of a round, found problems in a timely manner to contact, processing, the plate thickness of more than 8mm, is suggested to lose the round groove, the following 6mm, tooling plate pressure is groove.(2) stainless steel head, should be in the groove wall smearing splash front head agent, prevent groove, slag spout to head on the wall. (3) head onto the beveling machine before, first confirm the head weight, based on the weight of suitable sling, sling safety inspection.(4) head onto the groove machine, beveling rotary table adjustment screw rod, with a center adjusting position, rotating table, is aligned to the center.(5) groove, according to technology card height and height tolerance groove height ruler to draw lines, confirm the high line, the slope slope, should first slope flat groove, and then the slope groove.(6) outside the mouth or the inner groove angle should be controlled within ± 2.5 tolerance.(7) groove after, should check the head circumference, height, straight edge, angle, if not qualified to repair process, repair.(8) qualified head will remove and clean the slag grinding head internal slag, together with card transfer to the next process ( and sign their name ) by the next process inspector confirmation can be.6.polishing process6.1 polishing process steps(1) according to the card process requirements, identify the need for polishing head.(2) the head rotating table, determine the level of, the clamping head.(3) polishing from edge to center, or from the center to the edge; according to the diameter size determine the head beam, lower speed and working stage, after moving speed.(4) check the polishing condition, appropriate for rework.The 6.2polishing operation standard(1) according to the process card and materials to confirm the product instruction number, specifications, material, batch number, quantity, and check whether the workpiece has a drum kit, crack, delamination defects, and whether the loss of a round, found problems in a timely manner to contact, processing, check the appearance, to determine the need for manual processing, the polishing before hook head to mark.(2) according to the requirements of the choice of using a polishing, polishing pads, and the necessary auxiliary tool.(3) confirm the head weight, based on the weight of suitable sling, and check whether the safety hanger.(4) the head hanging onto a work table, adjust the center, at the same time to ensure that the head is in the basic level (0-5 deviations ).(5) people in the scene when polishing polishing, attention, especially the left centre, speed fast, or outward from a center left, a little pressure to increase, from the edge to the center of pressure during polishing, to a little decrease in polishing head, thin wall, as the case may be mounted shockproof wheel, at the same time attention to mechanical work has no abnormal.(6) after the completion of inspection head polishing, with or without defect, and the necessary contact.(7) the Polish well head with coated packaging, in the process card signed their names, together with the head and process the card with the circulation storage, and by the next inspection approval.封头加工工艺1.焊接工序1.1 焊接操作我们厂常用的焊接方法有:手工焊、氩弧焊、埋弧焊。

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