stress-tian
基于OrcaFlex的海洋柔性管水动力分析
基于OrcaFlex 的海洋柔性管水动力分析章仲怡(中海油能源发展股份有限公司清洁能源分公司,天津300450)摘要:柔性管水动力分析的准确性与保守性直接影响着其疲劳性能计算。
文章针对一种非黏结性柔性管,通过OrcaFlex 对其进行整体水动力分析,得到载荷曲线;并通过波浪筛选提取典型波浪工况,将其施加到OrcaFlex 分析模型中,得到了柔性管各位置处的载荷响应;最后提取了柔性管的最大弯矩和拉伸力数据,为下一步疲劳性能计算提供了数据支持。
关键词:非黏结性柔性管;力学响应分析;OrcaFlex ;弯矩;轴向拉伸力中图分类号:P75文献标志码:Adoi :10.13352/j.issn.1001-8328.2024.01.013Abstract :The accuracy and conservatism of hydrodynamic analysis on flexible pipes directly affect their fa⁃tigue performance calculation.This paper focuses on an unbonded flexible pipe and conducts an overall hydrody⁃namic analysis by OrcaFlex to obtain the load curve.Additionally ,it extracts typical wave conditions via wave screening and applies the conditions to the OrcaFlex analysis model for obtaining the load response at various posi⁃tions of the flexible tube.Finally ,the extracted maximum bending moment and tensile force data of the flexible pipe can provide data support for following fatigue performance calculation.Key words :unbonded flexible pipe ;mechanical response analysis ;OrcaFlex ;bending moment ;axialtensile force作者简介:章仲怡(1991-),男,天津人,工程师,大学本科,主要从事船舶与海洋工程结构物安装设计工作。
5071B主频标准说明书
5071BPrimary Frequency StandardFeatures• Easy to use with automatic startup and intuitive menu structure• Fast warm up ±5.0 x 10–13 accuracy in 30 minutes or less for high-per-formance tube• Integrated clock and message displays• Multiple timing and frequency inputs and outputs with easy access at front and rear• Automatic synchronization of 1PPS signal• Remote interface and controlincluding alarm output• Meets requirements in the new ITU-T G.811.1 ePRC standardBenefits• Maintains exceptional accuracy andstability even in unstable environ-ments—unsurpassed stability in thelab or field• Accuracy ±5.0 × 10–13 for highperformance• Stability ≤5.0 × 10–12 for highperformance (for 1 second averag-ing time)• Environmental stability ±8.0 × 10–14for high performance (frequencychange for any combination ofenvironmental conditions)• Long-term stability ≤1.0 × 10–14 forhigh performance (for 5-day averag-ing time)• Proven reliability with an averagemean time between failures (MTBF)of greater than 160,000 hours• Full traceability to NIST• AC and DC input and internal bat-tery back-upThe 5071B primary frequency standardhas the accuracy and stability you needfor both laboratory and field applica-tions. A stability specification for 30-day averaging time means the 5071Bwill keep extremely predictable timeand phase for long periods. Further,the 5071B can be used for long-termaveraging of noisy signals such as GPS.The 5071B is easy to use. No moremanual start-up steps or complicatedadjustments—everything is automatic.A logical menu structure simplifiesfront panel operations, selections,and status reporting. Remote controlfeatures tailor the 5071B for completeoperation and manageability in virtu-ally any location.Meeting the Needs of Leading- EdgeMetrology and Calibration LabsTimekeeping and National StandardsLaboratories verify the stability andaccuracy of their in-house cesiumstandards to Coordinated UniversalTime (UTC), provided by the BureauInternational des Poids et Mesures(BIPM) in Paris. A standard’s accuracyand reliability determine the qualityof service these timekeeping labsprovide. Of even greater concern is thestability of a standard. Stability directlyaffects a laboratory’s ability to delivertimekeeping and calibration services toits clients.The 5071B offers exceptional stabilityand is the first cesium standard tospecify its stability for averaging timeslonger than one day. The instrumenttakes into account environmentalconditions that can heavily influencea cesium standard’s long-term stabil-ity. Digital electronics continuouslymonitor and optimize the instrument’soperating parameters.Thus, the 5071B’s response to environ-mental conditions such as temperatureand humidity are virtually eliminated.The 5071B primary frequency standardmaintains its accuracy and stability,even in unstable environments.Satellite CommunicationsStable frequency generation is required to transmit and receive signals properly between ground terminals and com-munication satellites. Frequency flexibility is also needed to adjust for satellite-to-satellite carrier-frequency differences. The 5071B’s state-of-the-art technology produces offset and primary frequencies with the same guaranteed stability.For secure communications, precise timing synchroniza-tion ensures that encrypted data can be recovered quickly. Frequency-agile signals also require exact synchronization between transmitter and receiver during channel hops.The 5071B automates the synchronization to any external1PPS signal, greatly simplifying this aspect of satellite communications.The 5071B and GPSThe 5071B primary frequency standard can work very well with a GPS timing receiver to produce and maintain highly accurate time and frequency.The GPS system provides accurate time, frequency, and location information worldwide by means of microwave radio broadcasts from a system of satellites. Timing accuracy for the GPS system is based, in large part, on the accuracy and stability of a number of 5071B primary frequency standards. These standards are maintained by the GPS system, the US Naval Observatory, and various timing laboratories around the world that contribute to UTC, the world time scale. Because of their accurate time reference, GPS signals pro-cessed by a good GPS timing receiver can provide highly accurate time and frequency outputs. However, since GPS receivers rely on very low level microwave signals from the satellites, they sometimes lose accuracy because of interfer-ing signals, local antenna problems, or bad satellite data.In spite of these problems, a GPS timing receiver can be an excellent backup and reference to a local 5071B primary frequency standard. The GPS receiver provides an indepen-dent reference that can be used to verify the accuracy of a caesium standard, or it can be used as a temporary backup should the cesium standard need repair. The local 5071B standard has better stability, better output signal quality, and is not perturbed by interfering signals, intermittent signal loss, or bad satellite data.With these characteristics, the synergy created by combin-ing a good quality GPS timing receiver and a 5071B primary frequency standard can produce a highly robust, inexpensive, and redundant frequency and time system. Exceptional AccuracyThe intrinsic accuracy of the improved cesium beam tube (CBT) assures that any high performance 5071B will power up to within ±5.0 x 10–13 of the accepted standard for frequency. This is achieved under full environmental conditions in 30 minutes or less, and without the need for any adjustments or alignments.Unsurpassed StabilityThe 5071B high-performance cesium beam tube guarantees stability to be better than 1.0 x 10–14 for averaging times of five days or greater. The 5071B is the first cesium standard to specify stability for averaging times longer than 1.0 x 105 seconds (approximately one day).The 5071B is also the first cesium standard to specify and guarantee a flicker floor. Flicker floor is the point at which the standard’s stability (σy (2, τ)) does not change with longer averaging. The high performance 5071B flicker floor is guar-anteed to be 1.0 x 10–14 or better. Long-term measurements at the National Institute of Standards and Technology (NIST) show that the flicker floor is typically better than 5.0 x 10–15. Unstable environments are normal for many cesium stan-dard applications. The 5071B features a number of micropro-cessor controlled servo loops which allow it to virtually ignore changes in temperature, humidity, and magnetic fields.The 5071B delivers exceptional performance over very long periods of time, greatly increasing the availability of critical time and frequency services. Actual measurements made at NIST have demonstrated that a 5071B with the high-perfor-mance CBT will drift no more than 5.0 x 10–14 over the entire life of the CBT.Traditional ReliabilityThe 5071B design is based off its predecessor, the 5071A, which has demonstrated an average mean time between failures (MTBF) of greater than 160,000 hours since its introduction in 1992. This data is based on actual field repair data. Backing up this reliability is a 10-year warranty on the standard long-life cesium beam tube and a 5-year warranty for the high performance tube.Complete repair and maintenance services are available at our repair center in Beverly, Massachusetts.Full Traceability to NISTMicrochip provides NIST traceability to the accuracy mea-surements made on every 5071B. Traceability to NIST is maintained through the NIST-supplied Time Measurement and Analysis System (TMAS). This service exceeds the re-quirements of MIL-STD-45662A and can be a valuable tool in demonstrating traceability to your customers.High-Performance Cesium Beam TubeThe 5071A high performance cesium beam tube is optimal for the most demanding operations. The high-performance tube offers a full-environment accuracy specification of±5.0 x 10–13 —two times better than the specification for the standard tube. Stability is also significantly improved. The high-performance tube reaches a flicker floor of 1.0 x 10–14 or better, and long-term measurements at NIST show that the flicker floor is typically better than 5.0 x 10–15. Integrated Systems and Remote OperationToday, cesium standards are often integrated into telecom-munication, satellite communication, or navigation systems as master clocks. To accommodate these environments, the 5071A provides complete remote control and monitoring capabilities. Instrument functions and parameters can be interrogated programmatically.Communication is accomplished using the standard com-mands for programmable instruments (SCPI) language and a dedicated RS-232C port. Also, a rear panel logic output can be programmed to signal when user-defined abnormal condi-tions exist.For uninterruptible system service, an internal battery provides 45 minutes of backup in case of AC power failure. Thus, the 5071A can be managed easily even in the most remote locations.Straightforward OperationInternal microprocessor control makes start-up and opera-tion of the 5071A extremely simple. Once connected to an AC or DC power source, the 5071A automatically powers up to its full accuracy specifications. No adjustments or alignments are necessary during power-up or operation for the life of the cesium tube.An intuitive menu structure is accessible using the front panel LCD display and keypad. These menus—Instrument State, Clock Control, Instrument Configuration, Event Log, Frequen-cy Offset and Utilities—logically report status and facilitate control of the instrument. These functions are described as follows.Instrument StateOverall status is displayed, including any warnings in effect. Key instrument parameters such as C-field current, electron multiplier voltage, ion pump current, and cesium beam tube oven voltage are available. You can initiate a hard copy report of this data on your printer with the push of a button. Clock ControlSet the time and date, schedule leapseconds, adjust the epoch time (in 50 ns steps), and automatically synchronize the 1PPS signal to within 50 ns of an external pulse using this menu.Instrument ConfigurationSet the instrument mode (normal or standby) and assign frequencies (5 MHz or 10 MHz) to the two independently programmable output ports; configure the RS-232C data port. Event LogSignificant internal events (power source changes, hardware failures, warning conditions) are automatically recorded with the time and date of their occurrence. A single keystroke produces a hard copy on your printer for your records. Frequency Offset (Settability)Output frequencies may be offset by as much as 1.0 x 10–9 in steps of approximately 6.3 x 10–15. All product stability and output specifications apply to the offset frequency. UtilitiesThe firmware revision level and cesium beam tube identifica-tion information can be displayed.Accuracy and Long-term Stability11Lifetime accuracy (high performance CBT only) after a minimum two-month warm-up. Change no more than 5.0 × 10–14 for the life of the CBT.Specificationsfront panel or by remote control.The Microchip name and logo and the Microchip logo are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. All other trademarks mentioned herein are property of their respective companies. © 2023, Microchip Technology Incorporated and its subsidiaries. All Rights Reserved. 8/23DS00005002CRemote System Interface and Control RS-232-C (DTE configuration)Complete remote control and interrogation of all instrument。
drought stress
Research Report
Antioxidant Mechanism and Lipid Peroxidation Patterns in Leaves and Petals of Marigold in Respo to cell death (Imlay, 2003). It is known that antioxidant mechanisms, both enzymic and nonenzymic constituents, are involved in the protection of the plants against ROS. The antioxidant enzyme systems include superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), glutation reductase (GR) and dehydroascorbate reductase (DHAR) (Fover et al., 1994; Reddy et al., 2004). SOD is believed to play a crucial role in antioxidant defense because it catalyzes the dismutation of O2- into H2O2 whereas CAT and POD destroy H2O2 (Scandalios, 1993). Furthermore, previous studies demonstrated that antioxidant enzyme activities are positively correlated with plant stress
花椒味花生仁真空入味工艺优化及其品质分析
陈晓晴,廖卢艳,吴卫国. 花椒味花生仁真空入味工艺优化及其品质分析[J]. 食品工业科技,2024,45(8):190−199. doi:10.13386/j.issn1002-0306.2023050307CHEN Xiaoqing, LIAO Luyan, WU Weiguo. Optimization of Vacuum Flavoring Technology and Quality Analysis of Pepper-flavored Peanut Kernel[J]. Science and Technology of Food Industry, 2024, 45(8): 190−199. (in Chinese with English abstract). doi:10.13386/j.issn1002-0306.2023050307· 工艺技术 ·花椒味花生仁真空入味工艺优化及其品质分析陈晓晴,廖卢艳,吴卫国*(湖南农业大学食品科学技术学院,湖南长沙 412000)摘 要:花生传统加工方式存在能耗大、入味慢、加工周期长等缺点,为了得到风味更佳的花椒味花生仁休闲食品,本研究采用真空技术与传统技术相结合的加工方式,通过负压时间、负压次数、真空度三个单因素实验筛选真空入味工艺参数条件,以花椒酰胺含量和感官评分为考察指标,在单因素实验的基础上通过响应面试验优化真空入味花椒味花生仁的工艺条件。
结果表明,各因素对花椒味花生仁的影响顺序为负压时间>负压次数>真空度,最佳工艺参数为负压时间100 s 、负压次数6 次、真空参数0.80 MPa 。
该最佳工艺制作的花椒花生仁蛋白质含量为27%,脂肪含量为57%,过氧化值和酸价均符合国家的标准,感官评分为93.1分。
本研究以推动标准化加工的坚果休闲食品全产业链提供参考,促进坚果休闲食品产业的可持续发展。
关键词:花生仁,加工方式,响应面优化,品质分析本文网刊:中图分类号:TS202.1 文献标识码: B 文章编号:1002−0306(2024)08−0190−10DOI: 10.13386/j.issn1002-0306.2023050307Optimization of Vacuum Flavoring Technology and Quality Analysisof Pepper-flavored Peanut KernelCHEN Xiaoqing ,LIAO Luyan ,WU Weiguo *(College of Food Science and Technology, Hunan Agricultural University, Changsha 412000, China )Abstract :The traditional processing method of peanuts has drawbacks such as high energy consumption, slow flavor absorption, and long processing cycles, to get better flavor of pepper-flavored peanut kernel snack food, this study used the vacuum technology combining with traditional technology to optimize by examining the effect of negative pressure time,negative pressure times and vacuum degree on the content of zanthoxylamide and sensory score using a combination of single factor method and response surface design. The results showed that the order of influence of various factors on pepper-flavored peanut kernels was negative pressure time>negative pressure frequency>vacuum degree. The optimal process parameters were negative pressure time of 100 seconds, negative pressure frequency of 6 times, and vacuum parameter of 0.80 MPa. The protein and fat content of pepper-flavored peanut kernels produced by this optimal process were 27% and 57%, respectively. The peroxide value and acid value meet national standards, and the sensory score was 93.1 points. This study would provide a reference for promoting the standardized processing of the entire nut snack food industry chain, and promoted the sustainable development of the nut snack food industry.Key words :peanut kernel ;processing method ;response surface optimization ;quality analysis花生(Arachis hypogaea Linn.)别名长生果,原产于热带、亚热带的南美洲地区,是全世界第四大油料农作物,同时也是食用油脂和植物蛋白的重要来源[1−2]。
半导体器件 柔性可拉伸半导体器件 第5部分:柔性材料热特性测试方法-最新国标
半导体器件柔性可拉伸半导体器件第5部分:柔性材料热特性测试方法1 范围本文件规定了柔性材料热特性的测试方法。
本文件包括可用于评估和定义实际使用的柔性材料热特性的术语、定义、符号和测试方法。
测量方法依赖于基于温度相关光学反射的非接触光学测温。
本文件适用于可承受弯曲和拉伸的基板和薄膜等柔性半导体材料。
2 规范性引用文件本文件没有规范性引用文件。
3 术语和定义下列术语和定义适用于本文件。
3.1反射率 reflectanceρ特定波长和温度下材料表面对光通量的反射率。
注1:反射率可定义为反射光通量和入射光通量的比率或反射光通量和辐射的比率。
[来源:IEC 60050-845:1987,845-04-58,修改-增加了光学反射率的温度依赖性。
]3.2热调制反射谱 thermoreflectance热反射材料表面与温度相关的光反射率。
注1:热反射与热反射无关。
3.3局部温度 local temperatureT loc三维器件或系统局部区域的温度。
3.4平均温度 average temperatureT avg给定时刻下,基板目标区域的平均温度。
TT aaaaaa=1nn∑TT ll ll ll nn ii=1(ii) (1)式中:n —— 温度测试点的总数;T loc(i)—— 第i个测量点的局部温度3.5初始温度 initial temperatureT i样品即将通电时的局部或平均温度(t=0)3.6最终温度 final temperatureT f样品即将断电时的局部或平均温度(t=T f)。
3.7热时间常数 thermal time constantτ达到初始和最终温度差值的63.2%所需的时间。
3.8基板 substrate厚度超过探测激光波长20倍的材料。
注1:对于633 nm波长,基板的厚度应大于12.7μm。
3.9薄膜 thin-film厚度小于探测激光波长20倍的薄膜材料。
注1:对于633nm波长,薄膜的厚度小于12.7μm。
高中英语必修(第一册)-Unit 1 Section Ⅱ Lesson 2 Lesson 3 讲义
Section ⅡLesson 2 & Lesson 3Ⅰ.匹配词义A.单词匹配()1.stress A.n.功能()2.suffer B.adj.专业的,职业的()3.expert C.adj.困难的,难办的()4.function D.v t.&n.联系,联络()5.seek E.v t.以……为特色,是……的特征()6.professional F.n.专家,行家()7.feature G.n.压力;忧虑()8.tough H.v i.&v t.遭受(痛苦)()9.contact I.v t.寻求;请求()10.intend J.v t.计划,打算,想要[答案]1—5GHFAI6—10BECDJB.短语匹配()1.suffer from A.换句话说()2.to be frank B.有几分,有点()3.due to C.对付,应付,处理()4.in other words D.对……负责()5.graduate from E.放弃()6.sort of F.因为()7.give up G.(身体或精神上)遭受……(痛苦) ()8.deal with H.坦白说,坦率地说()9.be responsible for I.从……毕业()10.as well as... J.……以及……[答案]1—5 GHFAI6—10 BECDJⅡ.默写单词1.remove v t.移走;去掉2.organise v t.组织、筹划3.inspire v t.鼓励,激励4.apply v i.申请;请求5.eager adj.热切的;渴望的6.power n. 电,电力;力量7.responsible adj.负责的;有责任心的8.attractive adj.有吸引力的;好看的,美观的9.confident adj.自信的10.contribution n. 贡献Ⅰ.语境填空absolutely;charity;contact;downtown;feature;function;graduate;intend;position;sufferI went downtown to watch a flick with my roommate yesterday.2.He was the head of a charity for the welfare of children.3.Violence is now becoming a regular feature of urban life.4.He went through all the computers' functions with me.5.When the boys graduated from high school,Ann moved to a small town in Vermont.6.His family suffered all kinds of hardships during the war.7.He had intended to take a holiday in America.8.I contacted my uncle as soon as I went to Beijing.9.He replied that this was absolutely impossible.10.He had taken up a position in the centre of the room.Ⅱ.语法填空之派生词1.They began to recover slowly from their nightmare of pain and sufferings (suffer).2.I entirely(entire) agree with you.3.Tension(tense) is a major cause of heart disease.4.The human body has a very complex organisation(organise).5.Many of the performers were of professional(profession) standard.6.Genius is 10% inspiration(inspire) and 90% perspiration.7.We received 400 applications(apply) for the job.8.She's a very attractive(attract) woman.9.Laughter(laugh)is the best medicine.10.He was awarded a prize for his contribution(contribute) to world peace.1.After a long day,Zhang Tian finally got back to his small room,feeling tired.漫长的一天过后,张天疲惫不堪,终于回到自己的小窝。
吉林市极端气温变化特征及对玉米种植的影响分析
文章编号:1673-887X(2023)01-0123-04吉林市极端气温变化特征及对玉米种植的影响分析孙越,刘洋(吉林市气象局,吉林吉林132000)摘要文章选取吉林市1991年—2020年逐日最高、最低气温气象观测资料作为研究对象,利用数学统计法对极端气温变化特征进行分析,探讨了对玉米种植的影响及相关对策。
结果表明:吉林市极端高温主要出现在在5月—8月,以6月出现频率最高;极端最低气温集中在12月—次年2月,以1月出现频率最高;吉林市极端最高/最低气温均呈现出升降交替变化,以极端最低气温上升趋势较为显著;极端气温对玉米种植的影响较大,需要引起相关部门的高度关注。
关键词极端气温;玉米种植;吉林市中图分类号S162.5+3文献标志码A doi:10.3969/j.issn.1673-887X.2023.01.045Influence and Countermeasures of Extreme Temperature Change Characteristicson Maize Planting in Jilin CitySun Yue,Liu Yang(Jilin Meteorological Bureau,Jilin132000,Jilin,China)Abstract:This paper selected the meteorological observation data of daily maximum and minimum temperature in Jilin City from 1991to2020as the research object,analyzed the characteristics of extreme temperature changes using mathematical statistics,and discussed the impact on maize planting and relevant countermeasures.The results showed that the extreme high temperature in Jilin mainly occurs in May and August,with the highest frequency in June.The extreme minimum temperature is concentrated from De‐cember to February of the next year,with the highest frequency in January.The extreme maximum/minimum air temperature in Jilin City showed alternating changes,with the extreme minimum air temperature rising significantly.Extreme temperature has a great im‐pact on maize cultivation,which needs to be highly concerned by relevant departments.Key words:eextreme temperature,maize planting,Jilin City在联合国政府间气候变化专门委员会第5次评估报告中,指出了过去100年间,全球地表增温幅度在0.89℃左右,尤以20世纪70年代至今的增温趋势最为明显[1,2]。
北师大版高中英语同步测控必修第一册精品课件 UNIt 1 Section Ⅱ Lesson 2
Section Ⅱ Lesson 2 Understanding and Coping with Stress &
Lesson 3 Your Life Is What You Make It
走近新课·一起读文 阅读鉴赏·一起思考
词汇新知
一、单词英汉互译 1.suffer /̍sʌfə/ vi.& vt. 遭受(痛苦) 2.reduce /rI̍djuːs/ vt. 减少;降低;缩小 3.remove /rI̍muːv/ vt. 移走;去掉 4.position /pəz̍ Iʃən/ n. 职位;位置 5.absolutely /̍æbsəluːtli/ adv. 正是,当然 6.extent /Ik̍stent/ n. 程度 anise /̍ɔːɡənaIz/ vt. 组织,筹划
完成句子 ③我们希望他们会把租金降低一点。
We hope that they will reduce the rent ④劳动力已经减少了一半。 The workforce has been reduced by half
a little. .
3.In other words,you can make a list and do all the important things first.(Page 102) 换句话说,你可以列个清单,先做所有重要的事情。 ★in other words 换句话说 The manager asked her to leave.In other words,she was fired. 经理让她离开。换句话说,她被解雇了。
同义句转换
①He is honest and always keeps his promise.
fluent 超音速 总压 静压公式
超音速飞行是指飞行速度超过音速的飞行状态。
在超音速飞行中,飞行器面临着诸多挑战,其中之一便是气动力学问题。
而研究超音速飞行的气动力学问题,则需要涉及到总压和静压的概念及其计算公式。
总压和静压是描述流体流动状态的重要物理量,它们在超音速飞行中起着至关重要的作用。
在气动力学领域中,我们通常会涉及到流体的总压和静压,它们分别对应着飞机在飞行过程中遇到的不同情况。
下面我们将详细介绍总压和静压的概念及其计算公式。
一、总压总压是指流体在流动过程中的一种压力状态,它包括了动压和静压两部分。
动压是由于流体流动而产生的压力,而静压则是流体静止时的压力。
总压可以被理解为流体在流动过程中所具有的总压力。
总压的计算公式为:P0 = P + 0.5ρv^2其中,P0代表总压,P代表静压,ρ代表流体的密度,v代表流体的流速。
在超音速飞行中,总压对于飞机的设计和性能具有重要影响。
在超音速飞行时,流体的速度较大,因此动压部分所占比重较大,总压也相应增加。
了解总压的计算公式及其影响因素对于超音速飞行器的设计和性能分析至关重要。
二、静压静压是指流体在静止状态下所具有的压力。
在超音速飞行中,飞机表面会受到来自气流的冲击,这会导致飞机表面附近的气流速度增加,从而使得静压降低。
静压在超音速飞行中也具有重要作用。
静压的计算公式为:P = P0 - 0.5ρv^2其中,P代表静压,P0代表总压,ρ代表流体的密度,v代表流体的流速。
在超音速飞行中,静压的变化会直接影响到飞机的气动性能和结构设计。
准确计算和分析静压的变化对于超音速飞行器的设计和性能研究至关重要。
总压和静压是超音速飞行中重要的气动力学参数,它们的计算公式和影响因素直接关系到超音速飞行器的设计和性能。
深入研究总压和静压的变化规律对于超音速飞行器的研发具有重要意义,也是目前航空工程领域中的研究热点之一。
希望通过本文的介绍,读者能够对总压和静压有更加深入的了解,并且能够在超音速飞行器的设计和研究中加以应用。
(3) Stress at a Point and Stress Field
τxy=τyx τyz=τzy τzx=τxz
Infinitesimal cube
Stress components(分量 )in three ( dimensions
Nine components of stress at a point in matrix form
(5-2)
Stress ellipse defined by heads of stress vectors across various planes at a point. In this case the normal component of each stress is tensile (not compressive). (after W.D. Means,1976)
F vector
Unit: Newton 1 Newton = 1 kilogram meter per second squared scalar (only magnitude)
F1
F
F1 F F2 B
F2 A
Resolution and resultant of forces 力的分解与合成 A.A force F be resolved into two components F1 and F2. B. Two forces F1 and F2 be represented by the resultant F
Force力
Force is a kind of mechanical action between different objects, it tends to change the shape, volume or movement state of the object with a force upon it.
AK MASTER 试验规范中文版
国际规范目录页码前言 31. /2. /3.范围、参考资料与相关文件 44.特征数据 55.产品与功能说明以及检验计划 66.质量检查7 6.1程序7 6.2产品质量预先计划与测试计划8 6.3活动矩阵96.4.专有技术保护的证明材料127.1完整衬垫的测试与要求12 7.2物理数据13 7.2.1/2/3密度、孔隙率以及pH指数13-14 7.3力学性能与热性能15 7.3.1剪力与粘结剂15 7.3.2热压缩系数以及冷压缩系数17 7.3.3导热性19 7.3.4衬垫膨胀20 7.3.5防腐蚀性-背板涂层21 7.4摩擦行为、系数与测试程序21 7.5证明材料27 7.6计算制动转矩的公式277.7附录:衬面数据表288.附录1:7.6所述之制动转矩339.附录2:AK Master的测力计测试50前言在汽车产业中,客户与供应商之间的关系在世界范围内快速地变化着。
在竞争日益激烈以及成本压力增加的情况下,汽车制造商将越来越多的责任推向供应商。
面对着汽车产业、国际汽车平台以及国际企业等全球化进程的快速发展,制定关于摩擦衬面开发、发展以及质量保证的国际测试规范是无可辩驳的,也是当务之急。
根据“AK标准”(参见欧洲规范1与2)(AK标准的成员代表摩擦衬面以及客车制动器的大多数欧洲制造商)、德国摩擦材料产业协会/欧洲摩擦材料制造商协会团队“AK-QS”以及最新的国际测试规范,已经详细制定了国际规范的草案初稿。
为了获得广泛的同意与支持,下列概念与详细资料被提交至国际与国家研究机构以及相关国际企业以及公司集团。
所述的测试程序可根据不同汽车概念、企业特性与市场等适当考虑的因素进行灵活调整。
客户专用路面/驾驶测试以及特别测试补充了产品交付的程序。
本介绍书的基本目的如下:-把握项目阶段发展并将结果转化为生产。
-增加产品可靠性,同时控制检查成本。
-根据过程稳定性标准确定检查频率。
-制造过程的稳定性比最终检验程序更重要。
上海陆家嘴地区高空台风“温比亚”风特性实测
上海陆家嘴地区高空台风“温比亚”风特性实测傅国强,全涌†,顾明,黄子逢(同济大学土木工程防灾国家重点实验室,上海200092)摘要:基于上海环球金融中心顶部超声风速仪记录的台风“温比亚”风速样本数据,对平均风特性和湍流强度、阵风因子、峰值因子、湍流积分尺度和功率谱密度等脉动风风特性参数进行了详细分析.结果表明:1小时内在3s 、10min 和1h 3个时距的平均风速变化趋势一致.湍流强度呈现出随平均风速增加先下降后稳定的趋势,纵向和横向湍流强度均值分别为0.135和0.132;阵风因子均随湍流度的增大而增大,两者呈现线性增加的趋势;湍流积分尺度随平均风速增加而没有明显的变化趋势;Von-Karman 谱能够较好地拟合本次台风实测纵向和横向风速谱.关键词:台风;超高层建筑;现场实测;湍流强度;风特性中图分类号:TU311.3文献标志码:AField Measurement of Wind Characteristics of TyphoonRumbia in upper Air of Lujiazui District at ShanghaiFU Guoqiang ,QUAN Yong †,GU Ming ,HUANG Zifeng(State Key Laboratory of Disaster Reduction in Civil Engineering ,Tongji University ,Shanghai 200092,China )Abstract :Based on the wind speed samples collected by the ultrasonic anemometers atop Shanghai World Fi -nancial Center during Typhoon Rumbia,the fluctuating wind characteristics parameters,such as the mean wind char -acteristics,turbulence intensity,gust factor,peak factor,turbulence integral scale,and power spectral density are ana -lyzed in detail.It is found that the variation trends of the mean wind speed in 3seconds,10minutes and 1hour within an hour are consistent with each other.Turbulence intensity decreases first and then stabilizes with the augment of mean wind speed.The mean values of longitudinal and lateral turbulence intensity are 0.135and 0.132,respectively.The gust factor increases linearly with the increase of turbulence intensity.The turbulence integral scale shows no ob -vious variable trend with the increase of the mean wind speed.The measured wind speed spectra agree well with the Von -Karman spectra.Key words :typhoons ;super high-rise building ;field measurement ;turbulence intensity ;wind characteristics收稿日期:2019-09-10基金项目:国家自然科学基金资助项目(51778493),National Natural Science Foundation of China (51778493);土木工程防灾国家重点实验室自主课题(SLDRCE19-A-05,SLDRCE19-B-13),The Key Project of State Key Laboratory of Disaster Reduction in Civil Engineering (SL -DRCE19-A-05,SLDRCE19-B-13)作者简介:傅国强(1995—),男,广东韶关人,同济大学博士研究生†通信联系人,E-mail :*******************.cn *第48卷第1期2021年1月湖南大学学报(自然科学版)Journal of Hunan University (Natural Sciences )Vol.48,No.1Jan.2021DOI :10.16339/ki.hdxbzkb.2021.01.011文章编号:1674—2974(2021)01—0100—08傅国强等:上海陆家嘴地区高空台风“温比亚”风特性实测近年来,随着全球气候变暖,各种极端气候事件频发.2018年第21号超强台风“飞燕”登陆日本,最大瞬时风速达57.4m/s,造成了重大人员伤亡和财产损失,被日本称为25年来最强大的台风.我国东南沿海地区也是世界上受台风影响最严重的地区之一,仅2018年7月、8月两个月,就有5次台风先后登陆福建、上海和浙江.上海更是成为我国有气象记录以来首个30d内有3个台风正面登陆的城市.台风风场与常规风场有很大差异,在风洞试验中很难进行模拟,因此现场实测是现阶段最直接和最有效的研究手段,也是风工程研究中非常重要的基础性和长期性的研究方向[1].风工程研究发达的国家基于长期的现场实测数据建立起本地区的风特性数据库,如挪威[2]、英国[3]、加拿大[4]等都建有近海观测数据库.美国圣母大学[5-6]对芝加哥4栋高层建筑进行了长期的现场实测研究.近年来国内学者也开展了大量的实测研究,取得了一些进展.文献[7-12]在深圳平安金融中心、广州西塔、台北101等数十栋超高层建筑开展了多次现场实测研究,详细地分析了这些超高层建筑在台风作用下顶部的平均风速、风向、湍流度、阵风因子、峰值因子、湍流积分尺度和脉动风功率谱密度等风场特性和动力特性.Xu等[13]在深圳地王大厦对强风的平均和脉动特性,以及结构在强风下的响应进行了研究,并给出了相关的经验拟合公式;Guo等[14]通过在广州塔所布置的结构健康监测系统对3次台风作用下的平均风速、风向、湍流度等风特性和结构响应进行研究,与风洞试验对比并评估了舒适度.史文海等[15]对厦门某超高层建筑在某次台风作用下的风场和建筑表面风压进行了同步实测,对湍流度、阵风因子、脉动风功率谱以及平均风压系数和脉动风压系数进行了系统的研究.梁枢果等[16]对武汉某超高层建筑在良态风作用下的顶部风速与表面风压进行现场实测.何宏明等[17]利用台风“海马”登陆中心的观测塔的风速仪设备对不同高度处的风场特征参数进行了分析.张志田等[18]对江底河大桥桥址处深切峡谷的风场特性进行研究,详细分析了深切峡谷地形特征对风速风向及湍流特性的影响.沈炼等[19]对某山区峡谷桥址处风场进行了现场实测和数值模拟研究,得到了峡谷桥址处风场的详细分布特性.尽管许多学者在台风风特性实测方面做了大量的工作,并且在我国华南地区取得了丰硕成果,但是由于现场实测费用大、周期长、难度大,目前人们对台风风特性的认识还远不清楚.上海地区纬度相对较高,直接登陆的台风很少,因此在上海进行台风风特性现场实测对我国华东地区台风风特性的研究和扩充上海地区高空风速数据库具有非常重要的意义.本文利用上海环球金融中心顶部(497m)超声波风速仪采集到的台风“温比亚”风速数据,对平均风速、湍流强度、阵风因子、峰值因子、湍流积分尺度和脉动风功率谱进行了详细地分析.研究成果可为相近地区的超高层建筑抗风设计提供参考.1台风“温比亚”及现场实测概况2018年第18号台风“温比亚”(英文名:Typhoon Rumbia)于8月15日14时在东海东南部生成.8月16日21时加强为强热带风暴.8月17日4时在上海市浦东新区南部沿海登陆.登陆时由强热带风暴级减弱为热带风暴级,中心附近最大风力为9级,中心最低气压98.5kPa.台风“温比亚”登陆后向西偏北方向移动,强度逐渐减弱,在黄海北部海面变性为温带气旋,并于8月21日2时停止编号.在台风“温比亚”经过上海过程中,其先从东南方向逐渐靠近观测地点;8月17日5时其路径中心距离观测地点最近,距离达到18km;随后其逐渐向西并远离观测地点.上海环球金融中心(图1)位于上海市陆家嘴金融核心区,结构高度为492m,地上共有101层.金茂大厦(420.5m)和上海中心(632m)分别位于环球金融中心的西北部和西南部,除此之外其周围还密集分布有大量高层与超高层建筑,这使得环球金融中心的近地风特性极其复杂.上海中心上海环球金融中心金茂大厦正北方向X Y琢O(a)周边环境图(b)顶部俯瞰图图1上海环球金融中心周边环境和顶部俯瞰图Fig.1Surroundings and top view of the Shanghai WorldFinancial Center风速监测系统的观测点设置在上海环球金融中心101层东北端和西南端,两侧均安装有一台英国Gill公司生产Windmaster Pro超声风速仪(图1和图2),离地高度约494m,两端仪器间距约72m.超声风速仪的3个分量U,V,W分别对应正北、正西和竖第1期101直向上,风向角按俯视逆时针方向递增,以南风为0°,东风为90°,如图2所示.超声波风速仪风速量程为0.01~65m/s ,采样频率为10Hz ,采样得到的数据通过Campbell 公司生产的CR3000数据采集系统实时存储.为避免来流风受到环球金融中心顶部女儿墙、擦窗机、建筑本身等绕流影响,经过计算流体力学(Computational Fluid Dynamics ,CFD )计算得知,当来流方向在以东北角和西南角连线为平分线22.5°范围内可忽略绕流影响,即东北端有效风向角为112.5°~157.5°,西南端有效风向角为292.5°~337.5°.顶部视图VU正北(a )超声风速仪(b )方向定义图2超声波风速仪Fig.2Windmaster pro ultrasonic anemometer2台风“温比亚”风特性分析2.1平均风特性选取东北端超声风速仪从2018年8月15日20:00至8月17日16:00采集得到的共44h 的风速时程数据作为平均风特性分析样本.本文利用矢量分解法[20]对采集得到的风速数据进行处理,得到平均水平风速U 和平均水平风向角椎.由于风速的竖向分量对高层建筑影响较小,所以这里不考虑竖向平均及脉动风速.根据中国《建筑结构荷载规范》[21],本文以10min 作为分析时距,可得到264个连续的10min 风速时程样本.图3和图4分别为东北端纵向10min 平均风速和10min 平均风向角变化情况.从图3中可以看到,10min 平均风速随着时间呈现出先升高后降低的趋势.2018年8月16日10时至8月17日2时,10min 平均风速从11.33m/s 逐渐增大,最大风速达到22.52m/s ,随后逐渐减小到3m/s 左右.从图4中可以看到,10min 平均风向角先在120°至180°左右波动,随着台风“温比亚”登陆和远离上海,平均风向角瞬间增大至270°,之后逐渐稳定在190°左右.25201510520:0001:0006:0011:0016:0021:0002:0007:0012:0016:00时刻/h图310min 平均风速Fig.310min mean wind speed3603002401801206020:0001:0006:0011:0016:0021:0002:0007:0012:0016:00时刻/h图410min 平均风向角Fig.410min mean wind directon结构抗风设计中,不同时距平均风速的相互关系具有重要工程价值和理论意义.张相庭[22]根据国内外学者对不同时距平均风速的研究比较,统计得到近似比值关系,如表1所示.表1不同时距平均风速近似比值关系Tab.1The approximate ratio of the mean wind speed with different time interval风速时距1h10min 1min 30s 20s 10s 3s 瞬时统计比值0.941.001.201.261.281.351.421.50图5为1h 内时距分别为3s 、10min 和1h 的平均风速变化情况.可以看到,3s 、10min 、1h 3个时距的平均风速变化趋势一致.随着时距减小,最大平均风速逐渐增大,其中1h 内3s 最大平均风速为29.10m/s ,发生在2018年8月17日5时.湖南大学学报(自然科学版)2021年10220:0001:0006:0011:0016:0021:0002:0007:0012:0016:0035302520151053s10min 1h时刻/h图51h 内不同时距最大平均风速Fig.5Maximum mean wind speeds in 1hwith different time interval图6和图7分别为3s 最大平均风速随10min平均风速变化关系和10min 最大平均风速随1h 平均风速变化关系.从图中可以看出,3s 最大平均风速与10min 平均风速和10min 最大平均风速与1h 平均风速均呈现出很好的线性关系.本文实测结果与张相庭[22]的统计近似比值存在一定的差距,这应该是观测高度差异所导致的.本研究观测高度离地近500m ,风速的湍流强度应该低于离地高度较小的区域,这导致短观测时矩和长观测时矩的最大风速之比减小.101214161820222430282624222018161412本文实测y =1.32x10min 平均风速/(m ·s -1)图63s 最大平均风速随10min 平均风速变化关系Fig.6Maximum 3s mean wind speed versus10min mean wind speed2.2脉动风特性本文选取2018年8月16日13:30至8月17日03:00东北端采集得到的有效风向角范围内的数据进行分析.下文中如无特殊说明,分析时距均为10min.91113151719212422201816141210本文实测y =1.14x1h 平均风速/(m ·s -1)图710min 最大平均风速随1h 平均风速变化关系Fig.7Maximum 10min mean wind speed versus 1h mean wind speed2.2.1湍流强度湍流强度描述了风速随时间变化的程度,反映了脉动风的相对强度,是描述脉动风特性的重要参数.湍流强度通常定义为10min 时距内脉动风速标准差与水平平均风速U 的比值.I i =σi U(i =u ,v )(1)式中:I i (i =u ,v )分别为纵向和横向湍流强度;σi (i =u ,v )分别表示脉动风速u (t )和v (t )在10min 时距内的标准差.图8为纵向和横向湍流强度随10min 平均风速变化的关系.从图中可以看出,当10min 平均风速小于16m/s 时,纵向和横向湍流强度均随着10min 平均风速增加而下降,但当10min 平均风速大于16m/s 后两者却没有明显的变化趋势.1012141618202224I uI v0.400.350.300.250.200.150.100.05010min 平均风速/(m ·s -1)图8湍流强度与10min 平均风速的关系Fig.8Turbulence intensities versus 10min mean wind speed纵向和横向湍流强度均值分别为I u =0.135,I v =傅国强等:上海陆家嘴地区高空台风“温比亚”风特性实测第1期1030.132,两者比值为I u∶I v=1∶0.98.An等[23]、Quan等[24]和黄子逢等[25]分别分析了在台风“梅花”作用下,良态强风作用下和台风“灿鸿”作用下环球金融中心顶部湍流强度随10min平均风速变化情况,表2为4次现场实测结果对比.从表2可知,本文实测的湍流强度与An等实测结果接近,与Quan等、黄子逢等实测结果存在差异.这是因为Quan等只对良态强风进行了分析;黄子逢等则忽略了平均风速较低的数据,只分析了10min平均风速大于16m/s的样本.4次实测结果都呈现了湍流强度随平均风速增加而减小的规律.日本建筑荷载规范[26]中地貌相似(V类)、高度相同处(494m)的纵向湍流强度约为0.11,中国建筑结构荷载规范中相同地貌(D类)、相同高度(494 m)的纵向湍流强度为0.12,本文实测结果比两者略大.表2实测湍流强度对比Tab.2Comparison of turbulence intensities研究方法风场类型I u I v I u∶I v An等[23]台风“梅花”0.140.131∶0.93 Quan等[24]良态强风0.0850.0751∶0.88黄子逢等[25]台风“灿鸿”0.1070.0661∶0.62本文方法台风“温比亚”0.1350.1321∶0.98 2.2.2阵风因子风速的极值特性是风特性分析中十分重要的部分.阵风因子反映了阵风风速与平均风速之比,定义为阵风持续时间t g(本文取3s)内最大平均风速与分析时距(10min)的水平平均风速U之比,即G u(t g)=1+max(u(t g))U(2)G v(t g)=max(v(t g))U(3)式中:G i(t g)(i=u,v)分别为纵向和横向阵风因子;max(u(t g))和max(v(t g))分别表示纵向和横向脉动风在分析时距(10min)内阵风持续时间t g的最大平均风速.图9为纵向和横向阵风因子G u、G v随10 min平均风速变化情况.从图中可以看出,G u随平均风速增加没有明显的变化趋势,G v则先随着平均风速的增加而逐渐减小,当10min平均风速大于16m/ s后逐渐趋于稳定.G u、G v平均值分别为1.26、0.37,两者比值为G u∶G v=1∶0.29.An等,Quan等和黄子逢等也对阵风因子进行了分析,见表3.从表中可以看出,本文实测结果与An等实测结果接近,G u和G v与Quan等实测结果相差比较大,G v与黄子逢等实测结果存在差异,原因与上文中湍流强度存在差异的原因相同.10121416182022241.81.61.41.21.00.80.60.40.2G uG v10min平均风速/(m·s-1)图9阵风因子与10min平均风速关系Fig.9Gust factors versus10min mean wind speed表3实测阵风因子对比Tab.3Comparison of gust factors研究方法风场类型G u G v G u∶G vAn等[23]台风“梅花” 1.280.311∶0.24 Quan等[24]良态强风 1.150.171∶0.15黄子逢等[25]台风“灿鸿” 1.230.181∶0.15本文方法台风“温比亚” 1.260.371∶0.29阵风因子和湍流度之间的关系是风特性分析中重要的脉动参数关系.图10为纵向和横向阵风因子与湍流强度之间的关系,从图10可知,纵向和横向的阵风因子均随着湍流强度增加而增加.Cao等[27]和Li等[28]利用实测数据对阵风因子和湍流强度的经验关系式进行了线性和非线性拟合,表达式可统一为:G u=1+aI b u ln(T/t g)(4)式中:a和b均为待拟合参数;T为分析时距,取10 min;t g为阵风持续时间,本文取3s.本文分别对纵向和横向阵风因子与湍流强度的关系进行线性和非线性拟合.线性拟合结果为G u=1.21I u+1.09,G v= 2.61I u+0.02;非线性拟合结果为G u=1+0.19I u0.67ln (600/3),G v=0.60I v1.09ln(600/3).从图10可知,G u与线性和非线性拟合结果接近,G v在低湍流强度时吻合得很好,随着湍流强度增加阵风因子略呈发散趋势.总体上G u和G v随着湍流强度的增加而呈现线湖南大学学报(自然科学版)2021年104性增加的趋势.1.61.41.21.00.80.60.40.200.050.100.150.200.250.300.350.40G u vs I uG v vs I v线性拟合(顺风向,R 2=0.80)线性拟合(横风向,R 2=0.88)非线性拟合(顺风向,R 2=0.79)非线性拟合(横风向,R 2=0.88)湍流强度图10湍流强度与阵风因子关系Fig.10Gust factors versus turbulence intensities2.2.3峰值因子峰值因子也是反映风速极值特性的重要参数.峰值因子表征了脉动风速的瞬时强度,定义为:g u =(U ^t -U )/σu(5)式中:g u 为峰值因子;U^t 为分析时距(10min )内阵风持续时间t g (3s )最大平均风速;σu 为分析时距内脉动风速u (t )标准差.图11为峰值因子随10min 平均风速变化的情况.从图中可以看到,峰值因子在平均风速小于16m/s 时受平均风速影响的规律性不明显.当平均风速大于16m/s 时,峰值因子呈现出随平均风速先增大后减小,并逐渐趋于稳定.总体来看,峰值因子呈现出随着10min 平均风速增大而略微增大的趋势,变化区间为[1.33,2.91],平均值为1.98.表4为4次实测峰值因子均值的对比.本次实测结果峰值因子均值稍低.4次实测结果的峰值因子均有随着10min 平均风速增大而增大的趋势.1012141618202224峰值因子均值3.53.02.52.01.51.00.5010min 平均风速/(m ·s -1)图11峰值因子与10min 平均风速关系Fig.11Peak factors versus 10min mean wind speed表4实测峰值因子对比Tab.4Comparison of peak factors研究方法风场类型g u An 等[23]台风“梅花” 2.11Quan 等[24]良态强风 2.06黄子逢等[25]台风“灿鸿” 2.11本文方法台风“温比亚”1.982.2.4湍流积分尺度湍流积分尺度定义了若干具有一定特征的代表性的涡旋尺度来表征湍流中涡旋的平均尺度.本文采用基于Taylor 假设自相关函数法计算纵向和横向脉动风速的湍流积分尺度.计算公式为:L xi=U σ2i 0.05σ2i0∫R i (τ)d τ(i =u ,v )(6)式中:L xi (i =u ,v )分别为纵向和横向湍流积分尺度;U 为10min 平均风速;R i (τ)(i =u ,v )为脉动风速的自相关函数;σ2i (i =u ,v )为脉动风速的方差.图12为纵向和横向湍流积分尺度随10min 平均风速变化情况.从图中可以看出,两个方向的湍流积分尺度随10min 平均风速增加而没有明显的变化趋势,纵向和横向湍流积分尺度的平均值分别为:261.06m 和136.93m ,L u ∶L v =1∶0.52.表5为4次实测结果对湍流积分尺度的对比.从表中可以看出,不同实测结果得到的湍流积分尺度之间有较大的差异,原因可能是An 等现场实测时环球金融中心周边建筑环境与现在存在较大的差别;Quan 等由于只是对良态强风进行分析而季风和台风之间的湍流结构存在明显的差异;黄子逢等通过拟合广义风速谱的方法所求的纵向和横向湍流积分尺度,其结果均偏小.根据日本建筑荷载规范计算环球金融中心顶部(497m )的纵向湍流积分尺度为405.79m ,本文实测结果偏小.8007006005004003002001001012141618202224L x u L x v10min 平均风速/(m ·s -1)图12湍流积分尺度与10min 平均风速关系Fig.12Turbulence integral length scaleversus 10min mean wind speed傅国强等:上海陆家嘴地区高空台风“温比亚”风特性实测第1期105表5实测湍流积分尺度对比Tab.5Comparison of turbulence integral length研究方法风场类型L u L v L u ∶L vAn 等台风“梅花”217.60117.981∶0.54Quan 等良态强风212.23198.281∶0.93黄子逢等台风“灿鸿”187.0072.001∶0.39本文方法台风“温比亚”261.06136.931∶0.522.2.5脉动风功率谱脉动风功率谱密度描述了湍流中不同尺度的涡的动能对湍流脉动动能的贡献,它在频域上的分布代表了湍动能在不同尺度上的能量分布比例.各国学者提出了几种具有代表性的拟合经验功率谱,分别为达文波特谱、冯卡门谱、卡曼谱以及哈里斯谱.冯卡门(Von-Karman )谱的表达式为:nS u (n)σ2u =4nL x u /U [1+70.8(nL x u /U)2]5/6(7)nS v (n)σ2v =4nL x v /U [1+755.2(nL x v /U )2][1+283(nL x v /U )2]11/6(8)式中:S u (n )和S v (n )分别为纵向和横向脉动风功率谱密度;σ2u 和σ2v 分别为相应的脉动风速方差;n 为脉动风速频率.图13和图14分别为实测得到不同平均风速下纵向和横向的归一化平均脉动风功率谱.从图中可以看出,高风速样本在高频段谱值比低风速样本大,在惯性子区内衰减速率也比低风速样本缓慢;不同平均风速下纵向和横向脉动风功率谱和相应的Von-Karman 谱均吻合得很好,在高频部分略大于Von-Karman 谱.10010-110-210-310-210-1100101102U =22.52m/s Von-Karman (U =22.52m/s )U =18.64m/s Von-Karman (U =18.64m/s )nL x u /U图13归一化纵向脉动风功率谱密度Fig.13Normalized power spectra density of longitudinal fluctuating wind speed10-210-110010110010-110-210-3U =22.52m/sVon-Karman (U =22.52m/s )U =18.64m/s Von-Karman (U =18.64m/s )nL x v /U图14归一化横向脉动风功率谱密度Fig.14Normalized power spectra densityof lateral fluctuating wind speed3结论本文通过对台风“温比亚”登陆上海前后上海环球金融中心顶部东北端超声风速仪记录的风速时程数据进行分析,可以得到以下结论:1)3s 最大平均风速与10min 平均风速呈现出较好的线性关系:y =1.32x ;10min 最大平均风速与1h 平均风速也呈现出很好的线性关系:y =1.14x .本文实测结果与张相庭[22]的近似统计比值存在一定的差距.2)纵向和横向湍流强度均值分别为0.135和0.132,比值为I u ∶I v =1∶0.98.湍流强度随着平均风速增加而下降,但当平均风速大于16m/s 后却没有明显的变化趋势.本文实测结果比中国规范和日本规范略大.3)纵向和横向阵风因子均值分别为1.26和0.37,比值为G u ∶G v =1∶0.29.G u 随平均风速增加没有明显的变化趋势,G v 随着平均风速的增加而逐渐减小.纵向和横向的阵风因子与湍流强度的线性拟合结果与非线性拟合结果吻合较好,表明G u 和G v 随着湍流强度的增加而呈现线性增加的趋势.4)峰值因子呈现出随着平均风速增大而增大的趋势.峰值因子的变化区间为[1.33,2.91],均值为1.98.5)纵向和横向湍流积分尺度均值分别为261.06m 、136.93m ,比值为L u ∶L v =1∶0.52.湍流积分尺度随平均风速增加而没有明显的变化趋势.6)实测台风“温比亚”纵向和横向脉动风功率谱与Von-Karman 谱吻合得很好.湖南大学学报(自然科学版)2021年106参考文献[1]顾明.土木结构抗风研究进展及基础科学问题[R].北京:科学出版社,2006:382—403.GU M.The research process and basic scientific issues about civilstructure[R].Beijing:Science Press,2006:382—403.(In Chi-nese)[2]ANDERSEN O J,LΦVSETH J.The Fr准ya database and maritime boundary layer wind description[J].Marine Structures,2006,19(2):173—192.[3]WILLS J A B,GRANT A,BOYACK C F.Offshore mean wind profile [R].London:Department of Energy,1986:86—226.[4]MCCLINTOCK J D,POND G S,DACIDSONL L W.Offshore wind gust climatologies,sea consult limited,report prepared for atmo-spheric environment[R].Ottawa:Canadian Climate Service CenterMarine Applied Unit,1998:97—109.[5]KIJEWSKI-CORREA T L.Full-scale measurements and system identification:a time frequency perspective[D].Notre Dame:TheUniversity of Notre Dame,2003:404—433.[6]KIJEWSKI-CORREA T L,PIRNIA J D.Dynamic behavior of tall buildings under wind:insights from full-scale monitoring[J].TheStructural Design of Tall and Special Buildings,2007,16(4):471—486.[7]ZHANG J W,LI Q S.Field measurements of wind pressures on a 600μm high skyscraper during a landfall typhoon and comparisonwith wind tunnel test[J].Journal of Wind Engineering and Indus-trial Aerodynamics,2018,175(12):391—407.[8]ZHANG J W,LI Q S.Wind tunnel test and field measurement study of wind effects on a600m high super-tall building[J].The Struc-tural Design of Tall and Special Buildings,2017,26(11):1385—1401.[9]FU J Y,WU J R,XU A,et al.Full-scale measurements of wind ef-fects on Guangzhou West Tower[J].Engineering Structures,2012,35(1):120—139.[10]LI Q S,ZHI L H,TUAN A Y,et al.Dynamic behavior of Taipei101 tower:field measurement and numerical analysis[J].Journal ofStructural Engineering,2011,137(1):143—155.[11]LI Q S,FU J Y,XIAO Y Q,et al.Wind tunnel and full-scale study of wind effects on China’s tallest building[J].Engineering Struc-tures,2006,28(12):1745—1758.[12]LI Q S,XIAO Y Q,WU J R,et al.Typhoon effects on super-tall buildings[J].Journal of Sound and Vibration,2008,313(3/4/5):581—602.[13]XU Y L,ZHAN S.Field measurements of di Wang tower during ty-phoon york[J].Journal of Wind Engineering and Industrial Aerody-namics,2001,89(1):73—93.[14]GUO Y L,KAREEM A,NI Y Q,et al.Performance evaluation of Canton Tower under winds based on full-scale data[J].Journal ofWind Engineering and Industrial Aerodynamics,2012,104/105/106:116—128.[15]史文海,李正农,罗叠峰,等.台风“鲇鱼”作用下厦门沿海某超高层建筑的风场和风压特性实测研究[J].建筑结构学报,2012,33(1):1—9.SHI W H,LI Z N,LUO D F,et al.Field measurements of boundarylayer wind field and wind pressure characteristics of a super-tallbuilding on Coast of the Xiamen City during passage of typhoon Me-gi[J].Journal of Building Structures,2012,33(1):1—9.(In Chi-nese)[16]梁枢果,彭晓辉,王磊,等.良态风作用下超高层建筑风压特性现场实测与风洞试验对比研究[J].土木工程学报,2015,48(5):35—43.LIANG S G,PENG X H,WANG L,et parative study betweenfield measurement and wind tunnel test for wind pressure on WuhanInternational Stock Building[J].China Civil Engineering Journal,2015,48(5):35—43.(In Chinese)[17]何宏明,雷旭,聂铭,等.台风“海马”登陆中心近地风场特性实测研究[J].建筑结构学报,2018,39(10):29—36.HE H M,LEI X,NIE M,et al.Field measurement research of nearground wind field characteristics at landing center during ty-phoon‘Haima’[J].Journal of Building Structures,2018,39(10):29—36.(In Chinese)[18]张志田,谭卜豪,陈添乐.丘陵地区深切峡谷风特性现场实测研究[J].湖南大学学报(自然科学版),2019,46(7):113—122.ZHANG Z T,TAN B H,CHEN T L.Study on field measurement ofwind properties near a canyon deep-cut to hilly land[J].Journal ofHunan University(Natural Sciences),2019,46(7):113—122.(InChinese)[19]沈炼,韩艳,蔡春声,等.山区峡谷桥址处风场实测与数值模拟研究[J].湖南大学学报(自然科学版),2016,43(7):16—24.SHEN L,HAN Y,CAI C S,et al.Experiment and numerical simula-tion for wind field of a long-span suspension bridge located inmountainous canyon[J].Journal of Hunan University(Natural Sci-ences),2016,43(7):16—24.(In Chinese)[20]项海帆,葛耀君,朱乐东,等.现代桥梁抗风理论与实践[M].北京:人民交通出版社,2005:7—47.XIANG H F,GE Y J,ZHU L D,et al.Modern theory and practice onbridge wind resistance[M].Beijing:China Communications Press,2005:7—47.(In Chinese)[21]建筑结构荷载规范:GB5009—2012[S].北京:中国建筑工业出版社,2012:30—63.Load code for the design of building structures:GB5009—2012[S].Beijing:China Architecture and Building Press,2012:30—63.(InChinese)[22]张相庭.工程结构风荷载理论和抗风计算手册[M].上海:同济大学出版社,1990:26—30.ZHANG X T.Wind pressure and calculation of wind-induced vibra-tion[M].Shanghai:Tongji University Press,1990:26—30.(InChinese)[23]AN Y,QUAN Y,GU M.Field measurement of wind characteristics of typhoon Muifa on the shanghai world financial center[J].Interna-tional Journal of Distributed Sensor Networks,2012,8(9):893739.[24]QUAN Y,WANG S,GU M,et al.Field measurement of wind speeds and wind-induced responses atop the shanghai world financial cen-ter under normal climate conditions[J].Mathematical Problems inEngineering,2013,2013:469—481.[25]黄子逢,顾明.上海环球金融中心顶部台风“灿鸿”风速实测[J].同济大学学报(自然科学版),2016,44(8):1205—1211.HUANG Z F,GU M.Field measurement of wind characteristics oftyphoon Chan-hom on Shanghai world financial center[J].Journalof Tongji University(Natural Science),2016,44(8):1205—1211.(In Chinese)[26]AIJ recommendations for loads on buildings:AIJ—2004[S].Tokyo:Architecture Institute of Japan,2004:614—618.[27]CAO S Y,TAMURA Y,KIKUCHI N,et al.Wind characteristics of a strong typhoon[J].Journal of Wind Engineering and IndustrialAerodynamics,2009,97(1):11—21.[28]LI L X,KAREEM A,XIAO Y Q,et al.A comparative study of field measurements of the turbulence characteristics of typhoon and hur-ricane winds[J].Journal of Wind Engineering and Industrial Aero-dynamics,2015,140(12):49—66.傅国强等:上海陆家嘴地区高空台风“温比亚”风特性实测第1期107。
泛用压力调节器产品说明书
R07Miniature Series 07General Purpose Regulator1/8"and 1/4"Port Sizes q Compact designq Full flow gauge portsq Low torque, non-rising adjusting knobq Snap action knob locks pressure setting whenpushed inq Standard relieving models allow reduction of outletpressure even when the system is dead-endedq Can be disassembled without the use of tools orremoval from the air lineTechnical DataFluid: Compressed airMaximum pressure: 20 bar (300 psig)Operating temperature: -20°to +65°C (0°to +150°F) **Air supply must be dry enough to avoid ice formation at temperaturesbelow +2°C (+35°F).Typical flow at 10 bar (150 psig) inlet pressure, 6,3 bar (90psig) set pressure and a droop of 1 bar (15 psig) from set:1/8"ports: 6,5 dm3/s (14 scfm)1/4"ports: 7 dm3/s (15 scfm)Gauge ports:1/8"PTF with PTF main ports1/8"ISO Rc with ISO Rc main ports1/8"ISO Rc with ISO G main portsMaterials:Body: ZincBonnet: AcetalValve: Brass/nitrileValve seat: AcetalElastomers: Nitrile Ordering InformationSee Ordering Information on the following pages.ISO SymbolsDeutsche Dokumentation steht noch nicht zur Verfügung. Bitte wenden Sie sich an unseren zentralen Katalogversand. Tel 02802 49257Zurück zum InhaltsverzeichnisPort Size Model Number Flow† dm 3/s (scfm)Weight kg (lbs)G1/8R07-100-RNKG 6,5 (14)0,19 (0.31)G1/4R07-200-RNKG 7 (15)0,19 (0.31)Ordering Information. Models listed include ISO G threads, relieving diaphragm, 0,3 to 7 bar (5 to 100 psig) outlet pressureadjustment range* without gauge.FLOW CHARACTERISTICSAIR FLOWO U T L E T P R E S S U R Ep s i gTypical Performance Characteristics†Approximate flow at 7 bar (100 psig) inlet pressure, 6.3 bar (90 psig) set pressure and a droop of 1 bar (14.5 psig) from set.Dimensions mm (inches)Panel mounting hole diameter 30 mm (1.19")Maximum panel thickness 0 to 6 mm (0 to 0.25")ItemPart Number All models18-025-003Bracket Kit ReferenceService kit includes slip ring, diaphragm, standard valve seat with o-ring, valve, valve spring.Bracket MountingUse 3 mm (1/8") screws to mount bracket to wall.WarningThese products are intended for use in industrial compressed air systems only. Do not use these products where pressures and temperatures can exceed those listed under ‘Technical Data’.Before using these products with fluids other than those specified, for non-industrial applications, life-support systems, or other applications not within published specifications, consult NORGREN.Through misuse, age, or malfunction, components used in fluid power systems can fail in various modes. The system designer is warned to consider the failure modes of all component parts used in fluid power systems and to provide adequate safeguards to prevent personal injury or damage to equipment in the event of such failure.System designers must provide a warning to end users in the system instructional manual if protection against a failure mode cannot be adequately provided.System designers and end users are cautioned to review specific warnings found in instruction sheets packed and shipped with these products.Water vapor will pass through these units and will condense into liquidif air temperature drops in the downstream system. Install an air dryer ifwater condensation could have a detrimental effect on the application.。
形容沙发舒适的作文英语
The art of crafting a comfortable sofa is a delicate balance of design, materials,and ergonomics.Its not just about the physical sensation of sinking into plush cushions,but also about the emotional connection one feels when they find their perfect spot to unwind.Lets delve into the experience of encountering such a sofa.Imagine entering a living room,the first thing that catches your eye is a sofa that beckons with its inviting silhouette.Its plush contours and the gentle curve of its backrest promise a sanctuary from the days hustle and bustle.The fabric,a blend of cotton and polyester,is soft to the touch,with a subtle sheen that speaks of quality and care.The color,a rich mocha, adds warmth to the room,making it feel like a cozy haven.As one approaches,the smell of fresh leather wafts through the air,a testament to the sofas newness and the craftsmanship that has gone into its making.The stitching is meticulous,with each line running straight and true,reinforcing the structure without detracting from the overall aesthetic.Sitting down,the sensation is immediate and gratifying.The cushions, filled with a blend of memory foam and highquality polyester fiber, conform to the bodys shape,cradling it in a gentle embrace.The memory foam adapts to the weight and heat of the body,providing personalized support that feels as if the sofa was made just for you.The backrest is slightly reclined,offering the perfect angle for relaxation.It supports the lumbar region,alleviating any tension that might have built up during the day.The armrests are just the right height,offering a placeto rest your arms without feeling too high or too low,ensuring that no matter how you sit,you feel at ease.The frame of the sofa is sturdy,made from kilndried hardwood that ensures durability and stability.Its designed to withstand the test of time, a piece of furniture that will be a part of your home for years to come.The legs,typically crafted from a polished hardwood or metal,add a touch of elegance and elevate the sofa,giving it a distinguished presence.One cannot overlook the importance of the sofas dimensions.Its not just about the length and width,but also about the depth.A sofa that is too shallow might not provide enough space to stretch out,while one that is too deep might make it difficult to sit upright.This particular sofa strikes the perfect balance,offering ample space for lounging while still being practical for everyday use.The design of the sofa is also worth mentioning.Its not overly ornate,but it has enough detail to make it stand out.The tufting on the backrest adds a touch of sophistication,while the rolled arms give it a classic,timeless look.Its a piece that can fit into any decor,from modern to traditional,and its versatile enough to be the centerpiece of any room.In conclusion,a comfortable sofa is more than just a piece of furniture its a sanctuary,a place where one can escape from the world and find solace. Its a testament to the skill of the designers and craftsmen who have put their heart and soul into creating something that not only looks good butfeels good too.Its a place where memories are made,where laughter rings out,and where one can truly relax and be at peace.。
lammps 米塞斯应力-概述说明以及解释
lammps 米塞斯应力-概述说明以及解释1.引言1.1 概述在固体力学领域,米塞斯应力是一种重要的应力概念,用于描述材料内部的剪切应力分布。
米塞斯应力的概念最早由德国物理学家奥圭斯特·米塞斯(August von Mises)提出,因此被命名为米塞斯应力。
在材料力学中,米塞斯应力是描述材料弹性体的剪切应力分布情况的一种重要参数。
通过对米塞斯应力的研究,可以更好地理解材料的力学性能,进而指导工程实践中的设计和优化。
本文将通过介绍Lammps软件的基本概念和米塞斯应力的理论基础,探讨在Lammps中如何模拟米塞斯应力,在实际仿真过程中如何应用和分析米塞斯应力的结果,以及展望未来的研究方向。
通过对Lammps与米塞斯应力的结合研究,有助于深入理解材料的力学行为,并在材料设计和工程应用中发挥重要作用。
1.2文章结构1.2 文章结构本文将首先介绍lammps在分子动力学模拟中的应用和基本概念,包括lammps的特点、优势以及适用范围。
接着将详细介绍米塞斯应力的概念和计算方法,解释其在材料科学和工程中的重要性。
随后,将重点讨论在lammps中如何模拟和计算米塞斯应力,包括设置参数、建立模型和分析结果。
最后,通过对lammps对米塞斯应力的应用和效果进行总结和讨论,展望未来在这一领域的研究方向和发展趋势。
通过本文的阐述,读者将对lammps和米塞斯应力有一个全面的了解,为后续的研究和实践提供指导和借鉴。
1.3 目的本文的主要目的是探讨在使用分子动力学模拟软件LAMMPS时如何模拟和分析米塞斯应力。
通过对米塞斯应力的介绍和LAMMPS软件的概述,我们将深入研究如何在模拟中应用米塞斯应力,并分析其在不同系统中的应用效果。
通过这篇文章,读者将能够了解如何在实际科学研究和工程问题中利用LAMMPS软件来模拟和分析材料的应力行为,为更深入地研究材料的力学性质提供基础和参考。
我们希望通过这篇文章的撰写,能够帮助读者更好地理解米塞斯应力以及在LAMMPS中的应用方法,促进相关领域的研究和交流。
CAE基础培训
备注:如果按钮右下方有小黑三角,左键按住 该按钮不放,可展开其他类似功能,向右移动 鼠标即可切换功能。 如:
创建新Part
Introduction to ABAQUS/CAE
➢Modeling Space
三维立体模型、二维平面模型、轴对称模型
➢Type
部件类型:可变形体、离散刚体、解析刚体 (为接触分析提供刚性表面)、欧拉体
Partition Cell
Extrude/Sweep Edges
通过拉伸或扫略形成切割面 1、选择被拉伸或扫略的边 2、指定方向进行拉伸或指定沿某边进行扫略
Introduction to ABAQUS/CAE
Partition Cell
Used N-sided Patch
通过选定边界形成切割面 1、确定选择边还是顶点
➢Combine Faces合并面
按住Shift,依次拾取2个以上的面
➢Combine Edges合并边
按住Shift,依次拾取2个以上的边
➢Ignore Entities忽略特征
Introduction to ABAQUS/CAE
Mesh Controls
体网格控制
Introduction to ABAQUS/CAE
导入进装配体
Create Instance实际就是将Part导入到 Assembly
在Parts栏进行部件的选取(可多选)
➢Dependent(mesh on part)
默认选项。
➢Independent(mesh on instance)
耗用内存较多,生成的inp文件也较大。
Auto-offset from other instances 在 多次调用同一Part进Assembly时应用。
2019年一、应激地概念-应激(stress);是指机体在受到各种内外环...演示课件-精选.ppt
特征。
精选
二 应激原
应激原(stressor):凡是能引起应激的各种因素。 应激原的分类 1、外环境因素 2、机体的内在因素:自稳态失衡是一类重要的应激原。 3 、心理、社会环境因素 心理社会因素作为应激原可引起良性应激或劣性应激, 因此应激对健康的作用是双重的。
精选
三 全身适应终合症
※ 全身适应终合症(general adaptatian syndreme,GAS): 如果劣性应激原持续作用于机体,则应激可表现一个动态的连 续过程,并最终导致内环境紊乱和疾病,将其称之为GAS。 并将其分为三期。由加拿大生理学家 selye首先提出的。
但是,过度强烈的交感—肾上腺髓质系统的兴奋,也引起明 显的能量消耗和组织分解,甚至导致血管痉挛,某些部位组织
精选
缺血,致死性心律失常等。
(二)下丘脑—垂体—肾上腺皮质激素系统(HPAS)
1 、HPA轴的基本组成单元 HPA轴的基本组成单元为下丘脑的室旁核(PVN),腺 垂体和肾上腺皮质。 室旁核作为该神经内分泌轴的中枢位点,上行主要与杏仁 复合体,海马结构,边缘皮质有广泛的往返联系,特别与杏仁 体有致密的神经纤维联系。下行则主要通过CRH与腺垂体和
肾上腺皮质进行往返联系和调控。
精选
2、应激时的基本效应
(1)应激时HPA轴兴奋的中枢效应:HPA轴兴奋释放的中枢
介质为促肾上腺素皮质激素释放激素(CRH)和ACTH,特别是
CRH,它可能是应激时最核心的神经内分泌反应。
①CRH最主要的功能是刺激ACTH的分泌促进糖皮质激素
(GC) 的分泌。
②CRH的另一重要功能是调节应激时的情绪行为反应:适量
第七章 应 激
第一节 概述
※ 一、应激的概念 应激(stress):是指机体在受到各种内外环境因素
- 1、下载文档前请自行甄别文档内容的完整性,平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益,请联系客服反馈,我们会尽快为您处理(人工客服工作时间:9:00-18:30)。
案
例
应激反应本来是机体正遭到外界强烈的刺激后, 经大脑皮层综合分析产生的一系列非特异性应答反 2 应,如神经兴奋,激素分泌增多,血糖升高,血压 上升,心率加快,呼吸加速等。应该说,这种情况 是正常的,其作用在于使机体能对刺激作出迅速而 及时的回答,只要其强度、频率和持续时间适当, 不但不会对人体造成损害,而且对保护机体有益。
第二节 应激的全身性反应
一、神经内分泌反应与全身适应综合征
二、急性期反应
一、神经内分泌反应与全身适应综合征
蓝斑-去甲肾上腺素能神经元轴(LC-NE)兴奋
神 经 内 分 泌 反 应
儿茶酚胺分泌↑
下丘脑-垂体-肾上腺皮质轴 (HPA)强烈兴奋 糖皮质激素分泌↑
(一)蓝斑-交感-肾上腺髓质轴(Locus ceruleus-sympatheticadrenal medulla axis,LC/N)
(2) 腹腔内脏血管的持续收缩可导致内脏器官缺血。
(3)外周小血管的长期收缩可使血压升高。
(4) 增加血液粘滞度,促进血栓形成。
⑸心率增快,心肌耗氧量增加,导致心肌缺血。
交感神经和肾上腺髓质变化
应激原
交感-肾上腺髓质系统兴奋
儿茶酚胺分泌增多 防御作用
交感神经活动过强 消极影响
增强 心功 改善 组织 供血
应激的细胞体液反应
AP Cell HSP Some enzymes Some cytokines
stressors
急性期反应蛋白
感染、炎症、创伤、烧伤、手术等应激原均能引 起人和动物血清中某些蛋白质迅速升高。这种反 应称为急性期反应(acute phase response, APR), 这些蛋白质被称为急性期反应蛋白(acute phase protein, APP)。 GAS描述的重点是应激时神经内分泌反应, APR 则描述应激时血浆蛋白成分的变化。
第一节 Hans Selye 和stress
Background :
世界著名的内分泌学家和应激研究领域 的先驱。首先提出应激、应激原和全身适应
综合征(general adaptation syndrome)的概
念,并系统研究了应激的发生机制以及对机 体的影响。
一、Concept
of stress
热休克蛋白是指细胞在高温(热休克) 或其他应激原作用下所诱导生成或合成增 加的一组蛋白质。
非分泌型蛋白
应激反应 ( stress response, SR ) 应激蛋白( stress proteins, SP)
(一) HSP的生物学特点
(1)诱导的非特异性 (2)存在的广泛性 (3)结构的保守性
(三)、GAS -----全身适应综合征
(一) 概 念
应激原持续作用于机体,应激表现为动态的连续过程,并
最终导致内环境紊乱和疾病。被称为全身适应综合征。 ( general adaptation syndrome)。肾上腺是一个关键器官。
(二)分 期
alarm stage
Resistance stage
少数蛋白质在APR时反而减少,如白蛋白, 前白蛋白,运铁蛋白等,称为负APP。
APP的生物学功能
启动迅速的机体防御机制
(1)抑制蛋白酶活化,减轻组织损伤;
(2)清除异物和坏死组织 ,CRP
(3)抗感染、抗损伤
(4)结合、运输功能
热休克蛋白(heat shock proteins, HSP)
exhaustion stage
警觉期(alarm stage)
(1)机体防御机制快速动员
(2)交感-肾上腺髓质系统兴奋为主
抵抗期(resistance stage)
(1)肾上腺皮质激素增多为主
(2)对特定应激原的抵抗程度增强 衰竭期(exhaustion stage)
(1)虽肾上腺皮质激素增高,但GC受体数量和亲和力均下降 (2)出现应激相关疾病的表现
3. 适应代偿意义
①刺激中枢神经系统的兴奋和警觉,以利机体协 调神经-内分泌反应; ②提高心输出量和血压:交感-肾上腺髓质兴奋 使心率增快,心肌收缩力增强和外周阻力增加, 从而提高心输出量和血压; ③血液重新分布:交感-肾上腺髓质系统兴奋时, 皮肤、腹腔内脏及肾等血管收缩,而脑血管口径 无明显变化,冠状动脉和骨骼肌血管扩张;
衰竭期
受体的数量和亲和力下降。 内环境紊乱,负效应出现,应激性疾病、 器官功能衰竭发生,甚者休克、死亡。
全身适应综合征
Characteristic 警觉期
Alarm stage
Significance
反应出现迅速,持续时间短 机体处于“临战状态”保 以交感肾上腺髓质兴奋为主 护防御机制的快速动员期 交感肾上腺髓质反应逐渐减 弱,肾上腺皮质激素分泌逐 渐增多 机体的防御储备能力逐 渐被消耗
④支气管扩张:儿茶酚胺引起支气管扩张,有利于
改善肺泡通气;
⑤促进糖原及脂肪分解:儿茶酚胺通过促进胰高血
糖素分泌及抑制胰岛素分泌而促进脂质动员及糖原
分解;
⑥影响其它激素的分泌:儿茶酚胺对绝大多数激素 的分泌有促进作用,但对胰岛素的分泌有抑制作用。
4、对机体的不利影响
(1) 导致情绪反应及行为改变。
(一) 中枢神经系统
■HPA轴适度兴奋有助于维持良好的学习能力和良好的 情绪。
■HPA轴过度兴奋或不足可引起CNS功能障碍,出现抑 郁、厌食,甚至自杀倾向。
(丧失意识时,多数神经内分泌改变是不可能出现。)
CNS是调控中心,认知是基本环节 中枢神经系 统(CNS) 参与GAS的主要部位与表现
室旁核 HPA过度兴 奋或不足, 出现抑郁、 厌食、自杀 等 多巴胺能、5HT能、GABA 能等神经元参 与神经精神反 应
分泌部位
腺垂体
变化
↑
作 用
镇痛,抑制交感-肾上腺髓 质过度兴奋,抑制ACTH 及GC的过多分泌 促进糖原异生和肝糖原分 解
胰岛α细胞
↑
胰岛素
ADH
胰岛β细胞
下丘脑(室旁核)
↓
↑
血糖↑
保水,维持血容量,增强 抵抗力
生长激素
醛固酮
腺垂体
肾上腺球状带
急性应激↑ 升高血糖,保护组织 慢性↓ ↑ 保Na+,维持血容量
蓝斑投射区
紧张、专注 程度↑;但过 度则生愤怒、 焦虑、恐惧
释放核心激 素CRH参与 反应
心血管系统
主要由交感-肾上腺髓质系统介导:
心率↑,心肌收缩力↑,CO ↑,
BP ↑,血液重分布
(二)HSP的生物学功能
帮助蛋白质的折叠(folding )、移位 (translocation )、复性(renaturation) 和降解( degradation )——分子伴娘 (molecular chaperone)功能.
Other protein s
HSP
倾向于与蛋 白质的疏水 基团结合
病理生理学 Pathophysiology
主讲教师:田 芳
本能? stress
应
激
目
1 概
述
录
2 应激的全身性反应 3 细 胞 应 激 反 应 4 应激时机体的代谢和功能变化 5 应 激 与 疾 病 6 病理性应激防治的病生基础
案
例
一位正值壮年的某国家机关工作人员,跳槽 到某公司担任部门主管。到了新公司后,他深感 压力之大和竞争之激烈,只要稍有不慎,就有遭 2 到淘汰的危险,不得不承受快速的工作和生活节 奏。另外,由于工作环境的改变,他对自己的期 望值也高起来了。但最近他的身体越来越差,经 常失眠,做恶梦,记忆力开始下降,心情变得烦 躁不安,动辄发火,有时甚至什么事也不想做, 似乎已经心力交瘁。这早、迅速,以交感—肾上腺髓质兴奋 为主,伴有肾上腺糖皮质激素增多,意义: 使机体处于警觉、动员状态。 fight or
flight 持续时间短
机体的适应、抵抗能力增强;肾上腺皮质激 素增多,主要是cortisol。机体表现出适应抵 抗能力增强,但防御储备能力消耗。
抵抗期
代谢增加,胸腺、淋巴结萎缩,免疫反应减弱, 易患感染性疾病。 肾上腺皮质激素持续增加,但糖皮质激素
1. LC-NE基本单元组成(中枢整合和调控作用)
大脑皮层 社会心理应激
边缘系统
情绪 反应
躯体刺激
下丘脑的室旁核 (PVN) 垂体
CRH
脑桥蓝斑
ACTH
肾上腺皮质
CRH(促皮质释放激素) ACTH(促肾上腺皮质激素)
肾上腺髓质 GC 儿茶酚胺
2. LC-NE的基本效应
(1)中枢效应 引起兴奋、警觉及紧张、焦虑等情绪反应。 应激启动HPA轴的关键(蓝斑上行纤维)。 (2)外周效应 血浆儿茶酚氨类物质浓度迅速增高。 (蓝斑的下行纤维)
抵抗期
Resistance stage
衰竭期
Exhaustion stage
再度出现警告反应期的症状; 机体抵抗能力耗竭 皮质激素分泌持续增高; 出现明显的内环境紊乱。
三个阶段是一个连续过程 上述三个阶段并不一定都依次出现
多数应激只引起第一、第二期的变化,
只有少数严重的应激反应才进入第三期。
二 细 胞 应 激 反 应
分解代谢↑、血糖↑、负氮平衡
血浆急性期反应蛋白↑
良性应激( eustress)
Preparing for Holidays
劣性应激 (distress)
Divorce Death Loosing a job
应激对健康的作用是双重的 适当应激——
动员机体的非特异适应系统,增强机体的适应
为高代谢率(分解代谢增强,合 成代谢减弱)。
应激原
下丘脑-垂体-肾上腺皮 质 糖皮质激素 促蛋白分解