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英文文献翻译

英文文献翻译

外文文献原稿和译文原稿Sodium Polyacrylate:Also known as super-absorbent or “SAP”(super absorbent polymer), Kimberly Clark used to call it SAM (super absorbent material). It is typically used in fine granular form (like table salt). It helps improve capacity for better retention in a disposable diaper, allowing the product to be thinner with improved performance and less usage of pine fluff pulp. The molecular structure of the polyacrylate has sodium carboxylate groups hanging off the main chain. When it comes in contact with water, the sodium detaches itself, leaving only carboxylions. Being negatively charged, these ions repel one another so that the polymer also has cross-links, which effectively leads to a three-dimensional structure. It has hige molecular weight of more than a million; thus, instead of getting dissolved, it solidifies into a gel. The Hydrogen in the water (H-O-H) is trapped by the acrylate due to the atomic bonds associated with the polarity forces between the atoms. Electrolytes in the liquid, such as salt minerals (urine contains 0.9% of minerals), reduce polarity, thereby affecting superabsorbent properties, especially with regard to the superabsorbent capacity for liquid retention. This is the main reason why diapers containing SAP should never be tested with plain water. Linear molecular configurations have less total capacity than non-linear molecules but, on the other hand, retention of liquid in a linear molecule is higher than in a non-linear molecule, due to improved polarity. For a list of SAP suppliers, please use this link: SAP, the superabsorbent can be designed to absorb higher amounts of liquids (with less retention) or very high retentions (but lower capacity). In addition, a surface cross linker can be added to the superabsorbent particle to help it move liquids while it is saturated. This helps avoid formation of "gel blocks", the phenomenon that describes the impossibility of moving liquids once a SAP particle gets saturated.History of Super Absorbent Polymer ChemistryUn til the 1980’s, water absorbing materials were cellulosic or fiber-based products. Choices were tissue paper, cotton, sponge, and fluff pulp. The water retention capacity of these types of materials is only 20 times their weight – at most.In the early 1960s, the United States Department of Agriculture (USDA) was conducting work on materials to improve water conservation in soils. They developed a resin based on the grafting of acrylonitrile polymer onto the backbone of starch molecules (i.e. starch-grafting). The hydrolyzed product of the hydrolysis of this starch-acrylonitrile co-polymer gave water absorption greater than 400 times its weight. Also, the gel did not release liquid water the way that fiber-based absorbents do.The polymer came to be known as “Super Slurper”.The USDA gave the technical know how several USA companies for further development of the basic technology. A wide range of grating combinations were attempted including work with acrylic acid, acrylamide and polyvinyl alcohol (PVA).Since Japanese companies were excluded by the USDA, they started independent research using starch, carboxy methyl cellulose (CMC), acrylic acid, polyvinyl alcohol (PVA) and isobutylene maleic anhydride (IMA).Early global participants in the development of super absorbent chemistry included Dow Chemical, Hercules, General Mills Chemical, DuPont, National Starch & Chemical, Enka (Akzo), Sanyo Chemical, Sumitomo Chemical, Kao, Nihon Starch and Japan Exlan.In the early 1970s, super absorbent polymer was used commercially for the first time –not for soil amendment applications as originally intended –but for disposable hygienic products. The first product markets were feminine sanitary napkins and adult incontinence products.In 1978, Park Davis (d.b.a. Professional Medical Products) used super absorbent polymers in sanitary napkins.Super absorbent polymer was first used in Europe in a baby diaper in 1982 when Schickendanz and Beghin-Say added the material to the absorbent core. Shortly thereafter, UniCharm introduced super absorbent baby diapers in Japan while Proctor & Gamble and Kimberly-Clark in the USA began to use the material.The development of super absorbent technology and performance has been largely led by demands in the disposable hygiene segment. Strides in absorption performance have allowed the development of the ultra-thin baby diaper which uses a fraction of the materials – particularly fluff pulp – which earlier disposable diapers consumed.Over the years, technology has progressed so that there is little if any starch-grafted super absorbent polymer used in disposable hygienic products. These super absorbents typically are cross-linked acrylic homo-polymers (usually Sodium neutralized).Super absorbents used in soil amendments applications tend to be cross-linked acrylic-acrylamide co-polymers (usually Potassium neutralized).Besides granular super absorbent polymers, ARCO Chemical developed a super absorbent fiber technology in the early 1990s. This technology was eventually sold to Camelot Absorbents. There are super absorbent fibers commercially available today. While significantly more expensive than the granular polymers, the super absorbent fibers offer technical advantages in certain niche markets including cable wrap, medical devices and food packaging.Sodium polyacrylate, also known as waterlock, is a polymer with the chemical formula [-CH2-CH(COONa)-]n widely used in consumer products. It has the ability to absorb as much as 200 to 300 times its mass in water. Acrylate polymers generally are considered to possess an anionic charge. While sodium neutralized polyacrylates are the most common form used in industry, there are also other salts available including potassium, lithium and ammonium.ApplicationsAcrylates and acrylic chemistry have a wide variety of industrial uses that include: ∙Sequestering agents in detergents. (By binding hard water elements such as calcium and magnesium, the surfactants in detergents work more efficiently.) ∙Thickening agents∙Coatings∙Fake snowSuper absorbent polymers. These cross-linked acrylic polymers are referred to as "Super Absorbents" and "Water Crystals", and are used in baby diapers. Copolymerversions are used in agriculture and other specialty absorbent applications. The origins of super absorbent polymer chemistry trace back to the early 1960s when the U.S. Department of Agriculture developed the first super absorbent polymer materials. This chemical is featured in the Maximum Absorbency Garment used by NASA.译文聚丙烯酸钠聚丙烯酸钠,又可以称为超级吸收剂或者又叫高吸水性树脂,凯博利克拉克教授曾经称它为SAM即:超级吸收性物质。

手机图形界面设计外文文献翻译最新译文

手机图形界面设计外文文献翻译最新译文

手机图形界面设计外文文献翻译最新译文XXX interface design for mobile phones。

With the increasing popularity of smartphones。

it has e essential to create XXX but also easy to use。

The article XXX that can be used to create effective mobile phone interfaces.nMobile phones have XXX part of our daily lives。

and their XXX-designed interface can make it easier for users to navigate through us features and ns。

XXX.Design PrinciplesOne of the key principles of mobile phone interface design is simplicity。

The interface should be easy to understand and use。

with clear and concise labels and XXX。

where the design elements should be consistent across different ns and screens.Design XXXXXX that can be used to create effective mobile phone XXX is the use of color。

where different colors can be used to distinguish een different XXX is the use of typography。

外文文献翻译中性化服装设计

外文文献翻译中性化服装设计

外文文献翻译中性化服装设计shirts。

XXX。

With the development of society and the progress of science and XXX。

people'XXX challenged。

and the XXX。

the design of XXX.2 Design of Neuter ClothingThe design of XXX。

It aims to break the XXX。

and present a more inclusive and diverse style。

The design of neuter clothing should be comfortable。

practical。

and nable。

It should not be XXX。

age。

or body shape。

The use of neutral colors。

simple lines。

and minimalist style is the main feature of XXX.The design of XXX the social and cultural background。

Different ns and XXX。

the design of neuter clothing should be adapted to the local culture and market demand。

The use of local materials。

nal crafts。

and cultural elements can add more value to the XXX.3 Market of Neuter ClothingIn recent years。

the market of XXX。

such as Zara。

H&M。

and Uniqlo。

The neuter clothing market share is increasing。

计算机 JSP web 外文翻译 外文文献

计算机 JSP web 外文翻译 外文文献

计算机 JSP web 外文翻译外文文献12.1 nEffective web n design involves separating business objects。

n。

and object XXX。

Although one individual may handle both roles on a small-scale project。

it is XXX.12.2 JSP ArchitectureIn this chapter。

XXX using JavaServer Pages。

servlets。

XXX of different architectures。

each building upon the us one。

The diagram below outlines this process。

and we will explain each component in detail later in this article.Note: XXX.)When Java Server Pages were introduced by Sun。

some people XXX。

While JSP is a key component of the J2EE n and serves as the preferred request handler and response mechanism。

it is XXX.XXX JSP。

the XXX that JSP is built on top of the servlet API and uses servlet XXX interesting ns。

such as whether we should XXX in our Web-enabled systems。

and if there is a way to combine servlets and JSPs。

餐饮O2O商业模式创新团购网站外文文献翻译

餐饮O2O商业模式创新团购网站外文文献翻译

餐饮O2O商业模式创新团购网站外文文献翻译The O2O industry is growing rapidly。

but many businesses are still struggling to turn a profit。

However。

the emergence of big data presents a new opportunity for the restaurant O2O industry。

This paper aims to analyze the current restaurant O2O business model and explore the potential of utilizing big data to design a new。

model。

By examining the value of this new n-making method。

we hope to develop an innovative restaurantO2O business model.Keywords: Big data。

Restaurant O2O。

Business model。

n mechanism1.nThe O2O industry is a rapidly growing sector that connects online and offline businesses。

However。

many O2O businesses have yet to find a sustainable way to generate profits。

With the rise of big data。

the restaurant O2O industry can now leveragethis technology to develop new business models。

道路路桥工程中英文对照外文翻译文献

道路路桥工程中英文对照外文翻译文献

道路路桥工程中英文对照外文翻译文献Asphalt Mixtures: ns。

Theory。

and Principles1.nsXXX industry。

XXX。

The most common n of asphalt is in the n of XXX "flexible" XXX them from those made with Portland cement。

XXX2.XXXXXX the use of aggregates。

XXX。

sand。

or gravel。

and a binder。

XXX for the pavement。

XXX。

The quality of the asphalt XXX to the performance of the pavement。

as it must be able to XXX。

3.PrinciplesXXX。

with each layer XXX layers typically include a subgrade。

a sub-base。

a base course。

and a surface course。

The subgrade is the natural soil or rock upon which the pavement is built。

while the sub-base and base courses provide nal support for the pavement。

The surface course is the layer that comes into direct contact with traffic and is XXX。

In n。

the use of XXX.The n of flexible pavement can be subdivided into high and low types。

体验营销外文文献翻译2019年译文3000多字

体验营销外文文献翻译2019年译文3000多字

体验营销外文文献翻译2019年译文3000多字XXX quality。

This shift is due to the XXX performance。

including customer n。

n。

XXX experiment。

taking into account both the XXX.2 XXXXXXXXX of the customer's experience。

including sensory。

nal。

cognitive。

XXX on the customer and to build long-term XXX.3 XXXXXX it creates a unique and memorable experience for the customer。

which can lead to increased customer n。

loyalty。

XXX differentiate the brand from its competitors and can lead to increased brand awareness and positive word-of-XXX。

XXX a strong nal n een the customer and the brand.4 XXXXXX marketing。

including events。

sponsorships。

product ns。

and XXX and can include trade shows。

festivals。

XXX totry out products and experience them firsthand。

XXX.5 CONCLUSIONXXX of the customer's experience。

companies can create nal ns with their XXX。

With the right methods and strategies。

微电子专业英语翻译

微电子专业英语翻译

当超量载流子被导入一个直接禁带半导体时,电子与空穴直接复合的几率 较高,这是因为导带的底部与价带的顶端位于同一线上,因此在禁带间跃 迁时,无需额外的动量。直接复合率R应正比于导带中含有的电子数目及 价带中含有的空穴数目。也就是 R=βnp 。其中β为比例常数。
As discussed previously, in thermal equilibrium the recombination rate must be balanced by the generation rate . Therefore , for an n-type semiconductor, we have Gth=Rth=βn no p no where nno and pno represent electron and hole densities in an n-type semiconductor at thermal equilibrium. When we shine a light on the semiconductor to produce electron-hole pairs at a rate GL(Fig.2.11(b)), the carrier concentrations are above their equilibrium values.
当超量载流子被导入一个直接禁带半导体时电子与空穴直接复合的几率较高这是因为导带的底部与价带的顶端位于同一线上因此在禁带间跃迁时无需额外的动量
2.5 Generation and Recombination Processes 载流子产生与复合过程
3. Characteristics of Diodes二极管特性 3.1 Introduction介绍
当电子从导带向下移到价带, 一个电子 - 空穴对消失。这 种反向过程称为复合,并以 复 合 率 Rth 表 示 , 如 图 2.11 ( a )所示。在热平衡状态 下,产生速率 Gth 必定等于 复合率 Rth ,所以载流子浓 度维持常数,且维持 pn=ni2 的状况。

行列式的计算外文文献及翻译

行列式的计算外文文献及翻译

1 The definition of determinant:n order determinant represented by the symbol nnn n nn a a a a a a a a a 212222111211n D =It represents the n!Algebra and items.These are all possible from different lines in different columns in the N element of the n nj j j a a a 2121 product.n nj j j a a a 2121symbols for )(21)1(n j j j τ-.When n j j j 21 iseven (odd) arrangement of the sign is positive (negative) .That is to sayn nn nj j j j j j j j j a a a 21212121)(n )1(D ∑-=τ.Here are∑nj j j 21 said the summation of all n order.Definition of determinant by inverse number given, should grasp the following four:(1) The total number of n order permutation is !n so the n order determinant expansion there are !n ;(2) Each item is taken from different lines, product of n elements in different columns;(3) The premise in subscript according to the natural number sequence, the parity of the inverse number each item in front of the sign depends on the column index consisting of the arrangement of the evidence, the other half, half of them take the negative; (4) A number is the value of determinant..Example 1: if the permutation inversions number n j j j 21 to I .How much is the inverse number and arrangement of 121j j j j n n -.Analysis:If the number of the original array.1j earlier than 1j large number of 1τ, a number of smaller than 1j number is 1)1(τ--n , and the number of new arrangement of 121j j j j n n -1j earlier than 1j large number of as 1)1(τ--n ; similarly, a number of the original arrangement set before 2j than 2j a large number of 2τ, a number of smaller than 2j number is2)2(τ--n , and the number of new arrangement of 2j earlier than 2j large number of as2)2(τ--n ; followed by analogy, a number of the original arrangement set before k j than k j large number of k τ, t he number of new arrangement in k j before the number greaterthan k j for ),,2,1()(n k k n k =--τ.Solution: a number of set the original permutation of k j than k j large number of k τ, a new arrangement ofk j earlier than k j large number of a number of),,2,1()(n k k n k =--τ. Because of I n =+++τττ 21 so Inverse numberarrangementof121j j j j n n - isI n n k n n n n nk k -=+++-+++-+-=--=-=∑2)1(211)(]01)2()1[(])[(τττττ2 basic theory2.1 Properties of n order determinantProperty 1: Transpose, determinant. That isnnn n n n a a a a a a a a a212222111211=nnn nn n a a a a a a a a a212221212111Property 2: a number multiplied by the determinant of a row is equal to the number is multipliedby this determinant. That is nnn n l l nnn n n l l n a a a a a a a a a k a a a ka ka ka a a a21ln 211121121ln 2111211= Nature 3: if a line is the two set of numbers and then the determinant equals two determinant and the determinant in addition to this, all with the original determinant of the correspondingline.nnn n n n nn n n n n nn n n n n n a a a c c c a a a a a a b b b a a a a a a c b c b c b a a a 21211121121211121121221111211+=+++ Nature 4: if the determinant of two lines of the same so determinant is zero. The so-called two lines of the same is corresponding elements of two lines of equal.Nature 5: if the determinant of the two line is proportional to the determinant is zero.02121ln21112112121ln 2111211==nnn n ini i l l n nn n n ini i l l n a a a a a a a a a a a a k a a a a a a a a a a a aNature 6: the same row to another row determinant factor.Nature 7: to wrap column position in two lines of the determinant of No. 2.2 basic theory1 ⎩⎨⎧≠=+++0,0,2211ji D A a A a A a jn in j i j i Where ij A is a cofactor of element ij a . 2 Reduction theoremB CA D A DCB A 1--=3CA CB A =4B A AB =5 the nonzero matrix K left by a row to another row determinant is the new block determinant and the original equal2.3 results of several special determinant 1 triangular determinantnn nnn n a a a a a a a a a 221122211211000=(Triangular determinant )nn nnn n a a a a a a a a a221121222111000=(Lower triangular determinant )2 diagonal determinantnn nna a a a a a 221122110000=3 Symmetric and anti-symmetric determinantnnn n nn a a a a a a a a a D 212222111211=To meet the )2,1,2,1(n j n i a a ji ij ===, D is calledsymmetric determinant000331332312232111312 n n n n nn a a a a a a a a a a a a D =To meet the )2,1,(n j i a a ji ij =-=, D is calledskew-symmetric determinant. If the order of n is odd then 0=D 4 Vandermonde determinant∏≤<≤-----==ni j j i n n n n n nn n a a a a a a a a a a a a a a D 111312112232221321)(1111。

声乐外文文献翻译

声乐外文文献翻译

声乐外文文献翻译___ has often focused on technical issues such as open throat。

breath control。

___ paper。

___ methods that place music at the center of vocal music ___。

___' music n and n。

which in turn will ___.To build a music-___。

we must first recognize the ___ singing。

we should view music as a ___ music into our teaching methods。

we can help students better ___ singing.___ music-centered teaching is to use singing training that emphasizes the n of music。

This involves teaching students to understand the meaning and n behind the lyrics and melody of a song。

By focusing on the deeper meaning of a piece of music。

students can better connect with the music and express ___ singing.Another important aspect of music-___' understanding of music。

By performing with a band。

students can betterappreciate the us components of a song。

英文文献和中文翻译Probing the Relationship of Long-Range Order in Nanodomain

英文文献和中文翻译Probing the Relationship of Long-Range Order in Nanodomain

对利用三元添置中子衍射得到的纳米级FeCo合金远程有序关系的探究1.简介由于具有非常高的饱和磁化强度和居里温度,FeCo合金在工业上是一种重要的工程材料。

这些合金在软磁材料的应用中发挥了重要作用,例如发电机和电动机。

进一步应用的例子是变压器磁芯,磁驱动传动器,高场磁体的磁极以及电磁阀。

在工业的大部分应用当中,面临的挑战是在保持磁性能的同时,如何提高FeCo合金的拉伸强度和韧性。

曾经尝试过的方法有改变合金设计(比如加入一些镍,钒,铌,钽,铬,钼三元金属)、进行退火处理或是采用先进的变形处理。

然而,在现代应用中,要求有更好的力学、磁学性能。

近几年来,由于对现代发电机和配电设备需求的增加,科学家在FeCo合金方面的研究兴趣与日俱增。

特别是在极端环境下,对电气应用的要求非常严格。

另一方面,针对FeCo合金的结构和物理性能,尤其是针对它的纳米结构系统提出了有趣的问题。

得益于低钴FeCo合金(钴占到质量分数的17%到35%)的发展,在满足所需的磁性能的同时,合金的成本才得以降低。

此外,较低的Co含量能够提高合金的延展性和韧性。

合金的力学性能和温度所决定的晶体结构有直接的联系。

在高温时,Fe、Co两元素随机分布在体心立方晶格上(图1 A2型结构)。

Co的含量占到29%到70%,这种无序的结构在低温状态下是不稳定的。

当温度低于远程无序的临界温度Tc时,Fe、Co将会被分配到两个相互穿插的原始立方晶格当中,并形成一个有序的B2型结构。

图1 二元合金FeCo的相图。

所讨论的三元合金的区域示意图。

B2型结构的合金有一些典型的特点。

比如说,“反结构”和“三点”机制产生的点缺陷能够导致晶格空位。

无序的B2型结构合金表现出波浪滑移,而局部无序型合金表现出平面滑移。

有序—无序之间的转变影响了FeCo合金的力学性能,比如合金韧性的改变、更脆的无序相、有序相等。

另外,磁性影响了结构的稳定性,造就了FeCo合金的有序性。

比如,在富铁FeCo合金中,磁有序稳定了体心立方结构,也稳定了来源于铁磁性B2相的有序性。

化学专业英语文献翻译

化学专业英语文献翻译

专业英语文献翻译Quantifying the Cluster of Differentiation 4 Receptor Density on Human T Lymphocytes Using Multiple Reaction Monitoring Mass Spectrometry。

ABSTRACT: Cluster of differentiation 4 (CD4) is an important glycoprotein containingfour extracellular domains, a transmembrane portion and a short intracellular tail. It locates on the surface of various types of immune cells and performs a critical role in multiple cellular functions such as signal amplification and activation of T cells。

It is well-known as a clinical cell surface protein marker for study of HIV progression and for defining the T helper cell population in immunological applications。

Moreover,CD4 protein has been used as a biological calibrator for quantification of other surface and intracellular proteins. However,flow cytometry, the conventional method of quantification of the CD4 density on the T cell surface depends on antibodies and has suffered from variables such as antibody clones, the ommatophore and conjugation chemistries, the fixation conditions, and the flow cytometric quantification methods used. In this study, we report the development of a highly reproducible na no liquid chromatography−multiple reaction monitoring mass spectrometry-based quantitative method to quantify the CD4 receptor density in units of copy number per cell on human CD4+ T cells. The method utilizes stable isotope—labeled full—length standard CD4 as an internal standard to measureendogenous CD4 directly, without the use of antibodies. The development of the mass spectrometry-based approach of CD4 protein quantification is important as a complementary strategy to validate the analysis from the cytometry-based conventional method。

商业插画外文文献翻译最新译文

商业插画外文文献翻译最新译文

商业插画外文文献翻译最新译文The use of commercial XXX form has XXX expressive nature has led to the XXX benefits。

XXX global creative industries have also given rise to a new n of illustrators who have established their own brands and expanded the XXX through the use of the。

and new media。

This n of art and business has created a new consumer market with significant purchasing power.2 The Value of Commercial nCommercial XXX a creative perspective。

it serves as a means of artistic XXX。

XXX through visual media。

In the business world。

commercial XXX。

The use of commercial XXX increase sales and customer loyalty。

making it an essential component of modern marketing strategies.3 XXXXXX n。

as it allows for the XXX and media。

as well as the development of a personal style and brand identity。

Successful commercial XXX with the needs of their clients。

英文文献及翻译(计算机专业)

英文文献及翻译(计算机专业)

英文文献及翻译(计算机专业)The increasing complexity of design resources in a net-based collaborative XXX common systems。

design resources can be organized in n with design activities。

A task is formed by a set of activities and resources linked by logical ns。

XXX managementof all design resources and activities via a Task Management System (TMS)。

which is designed to break down tasks and assign resources to task nodes。

This XXX。

2 Task Management System (TMS)TMS is a system designed to manage the tasks and resources involved in a design project。

It poses tasks into smaller subtasks。

XXX management of all design resources and activities。

TMS assigns resources to task nodes。

XXX。

3 Collaborative DesignCollaborative design is a process that XXX a common goal。

In a net-based collaborative design environment。

n XXX n for all design resources and activities。

英文文献翻译

英文文献翻译

Preparation and characterization of Ag-TiO2 hybrid clusters powders[1](Ag-TiO2混合团簇粉末的制备和表征)Abstract:液相电弧放电法被用于制备纳米Ag-TiO2复合超细粉末。

XRD和TEM图表明颗粒呈葫芦状形态,分布狭窄。

我们讨论了实验条件对产品的影响,比较了这种方法制备的粉末和其他γ射线辐照法制备的粉末。

Introduction:材料合成技术,提高了研究特定电子和光学特性的能力。

这也导致了设备和不同效应的快速发展,如集成光学型偏振器[1]和量子霍耳效应。

所需的长度尺度对于这些结构的控制是在纳米级别的[ 2 ]。

科学家面临的一个新的挑战是半导体量子点的生长,它具有新的光学响应,引起了对其基础物理方面和三阶非线性光致发光的应用等的研究兴趣。

这方面的一个例子是Ag-TiO2复合材料通过胶体方法合成[ 3 ]或由γ射线辐照法合成[ 4 ]。

对比其他制备超细金属颗粒的方法,γ射线辐照法能在室温的环境压力下产生粉末。

在这封信中,我们开发了一种新的方法,即液相电弧放电法,用以制备纳米复合材料,当它经水热处理可以得到纳米级别的超细粉。

Preparation and photocatalytic activity of immobilized composite photocatalyst (titania nanoparticle/activated carbon)[2]固定化复合光催化剂(TiO2纳米颗粒/活性炭)的制备和光催化活性研究Abstract:制备了一种固定化复合光催化剂——TiO2纳米颗粒/活性炭(AC),并研究了它在降解纺织染料的光催化活性。

AC通过油菜籽壳制备。

碱性红18(BR18)和碱性红46(BR46)被用来作为模型染料。

并采用了傅里叶变换红外(FTIR),波长色散X射线光谱(WDX),扫描电子显微镜(SEM),紫外可见分光光度法,化学需氧量(COD)和离子色谱(IC)分析。

变电站中英文资料对照外文翻译文献综述

变电站中英文资料对照外文翻译文献综述

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商业插画外文文献翻译

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行列式的计算外文文献及翻译

行列式的计算外文文献及翻译

1 The definition of determinant:n order determinant represented by the symbol nnn n nn a a a a a a a a a 212222111211n D =It represents the n!Algebra and items.These are all possible from different lines in different columns in the N element of the n nj j j a a a 2121 product.n nj j j a a a 2121symbols for )(21)1(n j j j τ-.When n j j j 21 iseven (odd) arrangement of the sign is positive (negative) .That is to sayn nn nj j j j j j j j j a a a 21212121)(n )1(D ∑-=τ.Here are∑nj j j 21 said the summation of all n order.Definition of determinant by inverse number given, should grasp the following four:(1) The total number of n order permutation is !n so the n order determinant expansion there are !n ;(2) Each item is taken from different lines, product of n elements in different columns;(3) The premise in subscript according to the natural number sequence, the parity of the inverse number each item in front of the sign depends on the column index consisting of the arrangement of the evidence, the other half, half of them take the negative; (4) A number is the value of determinant..Example 1: if the permutation inversions number n j j j 21 to I .How much is the inverse number and arrangement of 121j j j j n n -.Analysis:If the number of the original array.1j earlier than 1j large number of 1τ, a number of smaller than 1j number is 1)1(τ--n , and the number of new arrangement of 121j j j j n n -1j earlier than 1j large number of as 1)1(τ--n ; similarly, a number of the original arrangement set before 2j than 2j a large number of 2τ, a number of smaller than 2j number is2)2(τ--n , and the number of new arrangement of 2j earlier than 2j large number of as2)2(τ--n ; followed by analogy, a number of the original arrangement set before k j than k j large number of k τ, t he number of new arrangement in k j before the number greaterthan k j for ),,2,1()(n k k n k =--τ.Solution: a number of set the original permutation of k j than k j large number of k τ, a new arrangement ofk j earlier than k j large number of a number of),,2,1()(n k k n k =--τ. Because of I n =+++τττ 21 so Inverse numberarrangementof121j j j j n n - isI n n k n n n n nk k -=+++-+++-+-=--=-=∑2)1(211)(]01)2()1[(])[(τττττ2 basic theory2.1 Properties of n order determinantProperty 1: Transpose, determinant. That isnnn n n n a a a a a a a a a212222111211=nnn nn n a a a a a a a a a212221212111Property 2: a number multiplied by the determinant of a row is equal to the number is multipliedby this determinant. That is nnn n l l nnn n n l l n a a a a a a a a a k a a a ka ka ka a a a21ln 211121121ln 2111211= Nature 3: if a line is the two set of numbers and then the determinant equals two determinant and the determinant in addition to this, all with the original determinant of the correspondingline.nnn n n n nn n n n n nn n n n n n a a a c c c a a a a a a b b b a a a a a a c b c b c b a a a 21211121121211121121221111211+=+++ Nature 4: if the determinant of two lines of the same so determinant is zero. The so-called two lines of the same is corresponding elements of two lines of equal.Nature 5: if the determinant of the two line is proportional to the determinant is zero.02121ln21112112121ln 2111211==nnn n ini i l l nnn n n ini i l l na a a a a a a a a a a a k a a a a a a a a a a a aNature 6: the same row to another row determinant factor.Nature 7: to wrap column position in two lines of the determinant of No. 2.2 basic theory1 ⎩⎨⎧≠=+++0,0,2211ji D A a A a A a jn in j i j i Where ij A is a cofactor of element ij a . 2 Reduction theoremB CA D A DCB A 1--=3CA CB A =4B A AB =5 the nonzero matrix K left by a row to another row determinant is the new block determinant and the original equal2.3 results of several special determinant 1 triangular determinantnn nnn n a a a a a a a a a 221122211211000=(Triangular determinant )nn nnn n a a a a a a a a a221121222111000=(Lower triangular determinant )2 diagonal determinantnn nna a a a a a 221122110000=3 Symmetric and anti-symmetric determinantnnn n nn a a a a a a a a a D 212222111211=To meet the )2,1,2,1(n j n i a a ji ij ===, D is calledsymmetric determinant000331332312232111312 n n n n nn a a a a a a a a a a a a D =To meet the )2,1,(n j i a a ji ij =-=, D is calledskew-symmetric determinant. If the order of n is odd then 0=D 4 Vandermonde determinant∏≤<≤-----==ni j j i n n n n n nn n a a a a a a a a a a a a a a D 111312112232221321)(1111。

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一种简单的方法制备N掺杂二氧化钛空心球及其在可见光下高光催化活性的研究摘要以碳球为模板,采用水热法制备了氮掺杂二氧化钛空心球。

用X射线衍射仪(XRD),透射电子显微镜(TEM),比表面积测试仪(BET),X射线光电子能谱(XPS)和紫外可见漫反射光谱(DRS)对制备的空心球进行了表征。

以P25二氧化钛为基准,研究了TiO2空心球对活性艳红X-3B的光催化性能(CI活性红2)。

结果显示,二氧化钛空心球的光催化活性增强了很多。

二氧化钛空心球的表观速率常数几乎是P25二氧化钛的17倍。

1、引言由于纳米二氧化钛(TiO2)在降解污染物、制氢和金属去除领域广阔的应用前景,使其光催化性能得到了广泛的研究。

为了使这项处理技术运用到中,改善二氧化钛的制备方法是非常重要的。

形貌和微观结构对二氧化钛的光催化活性是非常重要的,并且受制备条件和方法的影响。

因为二氧化钛空心微球低密度、高比表面积、良好的表面渗透性以及很高的捕光效率,最近制备技术引起了极大的关注。

预期用二氧化钛空心微球作为光催化剂来提高能源转换效率和光催化活性。

另一方面,由于二氧化钛的禁带(锐钛相3.2eV)宽,工艺技术应用受到几个因素限制,其中最受限制的是利用紫外光(波长(λ)<387nm)作为激发源。

因此,对太阳光的吸收还达不到照射地面的10%。

由于对阳光的有效利用或对光谱的可见光区的利用的缘故,增大二氧化钛对光谱吸收的范围这项技术可能还会出现一个有吸引力的挑战,目的是创造新一代的光催化剂。

许多研究说,非金属元素掺杂TiO2(如氮,硫,碳)把二氧化钛光吸收边转向低能源,从而增加了在可见光区的光催化活性。

最近,Sun等报道了胶体碳球的制备。

碳球可以作为制备具有中空结构的金属氧化物的模板。

胶体碳球的表面是亲水性的,具有-OH和-C=O基团,这样就没有必要再进行表面改性了。

在本文中,为了提高二氧化钛可见光驱动光催化活性,我们用胶体碳球为模板制备了可见光响应N掺杂二氧化钛空心球。

接着,我们研究了它们在水溶液中对活性艳红X-3B的(CI活性红2)光催化降解。

2、实验2.1碳球的合成胶体碳球的制备,取6g葡萄糖溶于60mL的蒸馏水中,转入50mL的带有聚四氟乙烯内衬的高压釜中,在180℃保温4小时。

将产物离心,用蒸馏水超声分散洗涤五次,然后离心,再用乙醇超声分散洗涤五次。

得到的碳球在80℃下真空干燥2小时。

2.2N-掺杂二氧化钛空心球的制备尿素作氮源,用于清洗的蒸馏水在清洗前用石英亚沸高纯度水净化系统净化。

在N-掺杂二氧化钛空心球的合成中,将定量的尿素溶解到24mL乙醇和0.3g蒸馏水中,然后加入0.12g碳球。

在剧烈搅拌的情况下,将用乙醇稀释的钛酸丁酯滴入上述溶液中。

然后,该溶液保持回流条件下(约80℃)6小时,将该产品离心,洗涤和用乙醇超声分散三次。

在空气中室温放置12小时和60℃放置2小时,二氧化钛/碳复合颗粒形成了。

为了制备N掺杂二氧化钛空心球,TiO2/C复合颗粒在空气中500℃温度下煅烧3小时。

将尿素和二氧化钛的摩尔比控制为1或2,所得样品分别贴上NHT-1、NHT-2的标签。

不加尿素,用同样的方法制备中空二氧化钛,进行比较。

2.3表征在管压40kV、管流30mA,衍射角2θ设定为20°~80°的范围下,选用石墨单色辐射铜(Cu-Kα)的X射线衍射仪(XD-3A,Shimadazu公司,日本)对制备的样品的结构性能进行了分析。

利用透射电子显微镜(TEM,JEM2000EX)对空心球的形貌进行了表征。

二氧化钛空心球的紫外可见吸收光谱用Shimadazu生产的配备积分球的UV-2100观察。

BET比表面积测量用ASAP2020装置被氮气吸附在77K下进行。

结合能由含有Mg-Kα辐射的X射线光电子能谱仪(XPS)确定分析(ESCALBMK-Ⅱ)。

2.4光催化活性样品的光催化活性由活性艳红X-3B溶液(CI活性红2)的光催化降解测定。

1g的样品加入到200mL25mgL-1的X-3B溶液中。

在照明前,悬浮液避光搅拌30min得到X-3B 解吸平衡。

含有滤光器400nm的250W卤素灯(仪器公司,北京师范大学)被用来作为可见光光源。

在规定的时间间隔内,取出5ml悬浮液,然后使用紫外可见分光光度计在535nm处测定X-3B溶液的浓度。

3结果与讨论3.1氮掺杂二氧化钛空心球的表征图.1为空心球的X射线衍射(XRD)分析,图中显示了温度为500°二氧化钛相的形成,很窄的峰表明,二氧化钛空心球已经结晶。

如图所示,颗粒已经形成了锐钛矿相,在样品中有很明显的锐钛矿的特征衍射峰(主峰:25.4°,38.0°,48.0°,54.7°,63.1°)。

无其他如N-O和Ti-N的峰出现。

这可能是由于氮的含量太少以至于不能在光触媒下检测。

在500℃下煅烧,不仅去除了模板也形成了锐钛矿相。

而且由此得到的二氧化钛空心球的晶粒尺寸由Scherrer方程确定:D=(Kλ)/(βcosθ),其中λ是X射线衍射波长(λ=0.15418),K是Scherrer常数(K=0.9),θ是特征X射线衍射角(θ=12.7◦),β是在(101)平面的积分半高宽度(弧度)。

NHT-1和NHT-2的这些值分别估计为11.75nm 和12.35nm。

它表明了NHT-2的结晶度比NHT-1的更好。

从比表面积测试中看出,NHT-1的比表面积为361.27m2/g-1,而NHT-2的比表面积为319.32m2/g-1。

面积的减少可能是由于晶粒尺寸的增加。

碳球的TEM图像如图2(a)所示。

从图中可以看出,所制备的碳球的直径介于250~400nm。

图2(b)显示了NHT-2的TEM图像。

边缘之间的黑暗和中心明亮的强烈反差说明了二氧化钛空心球结构。

TEM图像也显示,利用碳球作为模板使球壳的表面更光滑和形成了致密的二氧化钛纳米层。

从中可以看出,空心球的平均直径为280nm和壳体厚度约为30nm。

图3比较了NHT-1、NHT-2和P25的紫外可见漫反射光谱。

结果表明,用这种方法掺氮可以引起二氧化钛空心球在光反应下清晰的红移。

高可见光吸光度(400-550nm)对N-掺杂样品进行观察。

此外,我们可以观察到NHT-2的红移和可见吸收相比较NHT-1是增强的。

这可能是在先前的尿素中较多的氮原子进入二氧化钛的晶格中。

因此,它引起较大的红移和带隙变窄。

X射线光电子能谱分析是用于检测不同原子掺杂二氧化钛光催化剂化学态的一种特征方法。

活性部位和氮的形态增强氮掺杂TiO2光催化活性是进年来光催化剂研究的最新课题。

对NHT-2的XPS调查光谱表明,高峰含有钛、氧、碳和氮原子。

碳原子的部分可能来自于前驱体溶液残余的碳。

碳原子的其他部分可能来自于煅烧碳球。

在NHT-2的表面,C1s和N1s区域的高分辨率XPS谱图分别如图4(b)和图4(c)所示。

从图4(b)中我们可以看到,有大约284.6eV和288.2eV的两个X射线光电子能谱峰。

据李等人在284.6eV的峰来自于不定元素碳。

其他围绕288.2eV的峰归因于碳酸盐种类的形成,可诱导掺杂二氧化钛的能隙缩小。

NHT-2的N1s的区域(如图4(c)所示)是宽的和不对称的,这表明至少有两种化学态。

在Gaussian原则下使用origin软件看到N1s的区域恰有两个高峰。

一峰在396eV,与所谓的β-N的状态相对应,这代表了混合钛氧化物-氮化物(TiO2-x N x),O-Ti-N。

这表明,在这项研究中使用了合成方法确实导致了一些氧位置被氮替代。

399.2eV周围的其他峰值可能是有N或C-N键的氧化状态的存在。

这可能是由于在二氧化钛颗粒表面化学吸附尿素分子。

从以上结果,我们可以预测制备的N掺杂二氧化钛空心微球在可见光照射下可以表现出高的光催化活性。

3.2二氧化钛空心球的光催化活性为了调查制备的N掺杂二氧化钛空心球样品的光催化活性,在可见光下研究了活性艳红X-3B(CI活性红2)的降解,并且结果都显示在图5中。

对无催化剂的空白实验进行了研究,2小时光照后大约有2%转化。

对于X-3B的降解率,趋势是NHT-2>NHT-1>P25。

由这个结果可以得出,三个样品的光催化活性以及对应的可见紫外可见漫反射光的吸收光谱。

此外,我们可以看到,HT的光催化活性高于P25,但比掺杂样品低。

结果说明,这两个空心球结构和N-掺杂影响了光催化活性。

众所周知,在水相悬浮物种有机污染物的光催化氧化符合Langmuir-Hinshelwood动力学模型如下:-dC/dt=k r K a C/(1+K a C) (1) 其中(-dC/dt)是X-3B的降解率,C是溶液中X-3B的浓度,t为反应时间,k r是反应速率常数,K a为吸附反应物系数。

当C值非常小时K a C可以忽略。

因此,方程(1)可以被描述为一级反应动力学。

设定方程(1)在光催化过程的初始条件,当t=0时,C=C0,它可以被描述如下:ln(C0/C)=k app×t (2) 其中k app是表观速率常数,根据不同的光催化剂被选择为基本的动力学参数,因为它使其确定了独立于在黑暗中前期吸附阶段和X-3B溶液的浓度的光催化活性。

在ln(C0/C)中作为照射时间的函数(含C0/C)的变化给出的图6。

得到的表观猝灭静态常数k app列于表1。

综上,我们可以得出结论,N掺杂二氧化钛空心球在可见光照射下对X-3B的降解表现出强烈的的光催化活性。

不同样品的光催化活性的不同可以归因于以下因素。

众所周知,N和C元素掺杂二氧化钛在二氧化钛的可见光光催化活性中起着的重要作用。

从NHT-1和NHT-2的紫外可见漫反射光谱中可以看出,造成了可见光区吸收剧烈的增加和吸收边的红移。

N掺杂二氧化钛导致禁带变窄增强了在可见光下二氧化钛空心球体的光催化活性。

由于制备的掺杂样品可通过可见光激活,从而更多的电子和空穴可以生成和参与光催化氧化还原反应。

此外,NHT-1和NHT-2的空心结构将表现出较高的能量转换效率。

4结论在本文中,我们提出一个以碳球为模板制备N掺杂二氧化钛空心球的简便方法。

碳球通过水热法合成的。

与P25二氧化钛相比,制备的二氧化钛空心球的光催化活性由在可见光照射下对活性艳红X-3B溶液的(CI活性红2)降解测定。

二氧化钛空心球的表观猝灭静态常数几乎是P25二氧化钛的17倍。

这种方法提供了一个绿色的,简单和经济的方法合成具有高的可见光照射光催化活性的均匀N掺杂二氧化钛空心球。

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