Tabor数、粘着数与微尺度粘着弹性接触理论

微电子机械系统（ＭＥＭＳ）等领域的飞速发展，促使我们迈进了一个表面效应在许多现象 中占主导地位的研究领域．本文重点介绍在ＭＥＭＳ中经常遇到的微尺度粘着弹性接触的相关理论． 通过对两个无量纲数——Ｔａｂｏｒ数μ（以及其相应形式）和粘着数θ的分析，以及考虑它们对于粘 着力的影响，指出了粘着弹性接触理论中所隐含的尺度效应，随着特征尺度的减小，粘着弹性接触中 的表面效应愈加明显．

Influence of Tire Slip Angle on Adhesion CoefficientCharacteristic of Road Vehicles

Tire slip angle has a great influence on peak values of both logitudinal and lateral adhesion coefficients as well as optimal slip ratios. Regression equations based on the experi- mental data from several countries are given to describe their dependencies. The peak value of longitudiinal adhesion coefficient has a linear relationship with tire slip angle, but peak value of lateral has a complicated relationship; the optimal slip ratio of longitudinal has an exponent function relationship, the optimal slip ratio of lateral almost has nothinng to do with tire slipangle.

Approach to estimation of vehicle-road longitudinal friction coefficient

According to the road adaptive requirements for the vehicle longitudinal safety assistant system an estimation method of the road longitudinal friction coefficient is proposed.The method can simultaneously be applied to both the high and the low slip ratio conditions. Based on the simplified magic formula tire model the road longitudinal friction coefficient is preliminarily estimated by the recursive least squares method.The estimated friction coefficient and the tires model parameters are considered as extended states. The extended Kalman filter algorithm is employed to filter out the noise and adaptively adjust the tire model parameters. Then the final road longitudinal friction coefficient is accurately and robustly estimated. The Carsim simulation results show that the proposed method is better than the conventional algorithm. The road longitudinal friction coefficient can be quickly and accurately estimated under both the high and the low slip ratio conditions.The error is less than 0.1 and the response time is less than 2 s which meets the requirements of the vehicle longitudinal safety assistant system.

Mathematical Models of Tire-Lateral Road Adhesion for Use in Road Vehicle Dynamics Studies

Mathematical models of tire-lateral mad adhesion for use in mad vehicle dynamics studies are set up to express the relations of adhesion coefficients with slip ratio in lateral direction.The models of tire-lateral mad adhesion revolutionize the Pacejka's model in concept and therefore make it possible for applications in vehicle dynamics studies by the expression of lateral adhesion coefficient as a function of wheel slip ratio,instead of the wheel slip angle,taking into account in the mean time the influences of mad surface condition, vehicle velocity,vertical load,tire slip angle,and wheel camber angle.

Crossed modules of Lie color algebras

The linear operations of the equivalent classes of crossed modules of Lie color algebras are studied. The set of the equivalent classes of crossed modules is proved to be a vector space, which is isomorphic with the homogeneous components of degree zero of the third cohomology group of Lie color algebras. As an application of this theory, the crossed modules of Witt type Lie color algebras is described, and the result is proved that there is only one equivalent class of the crossed modules of Witt type Lie color algebras when the abelian group Г is equal to Г＋. Finally, for a Witt type Lie color algebra, the classification of its crossed modules is obtained by the isomorphism between the third cohomology group and the crossed modules.

Climate Comfort Analysis of the East Section of Silk Road

Based on the meteorological data of 12 weather stations in the east section of silk road from 1971 to 2005, such as average monthly temperature, relative humidity, wind speed and sunshine duration, its climatic tourism comfort was analyzed by adopting temperature-humidity index, wind-chill index and index of cloth. The results showed that the most comfortable month for travelling in this region is May and September. From east to west, the climatic comfort of such a section is decreasing. The most suitable tourism season is summer, followed by autumn and spring, the least suitable season is winter.

Friction heat production and atom diffusion behaviors during Mg-Ti rotating friction welding process

An innovative physical simulation apparatus, including high speed camera, red thermal imaging system, and mechanical quantity sensor, was used to investigate the friction heat generation and atom diffusion behavior during Mg-Ti friction welding process. The results show that the friction coefficient mainly experiences two steady stages. The first steady stage corresponds to the Coulomb friction with material abrasion. The second steady stage corresponds to the stick friction with fully plastic flow. Moreover, the increasing rates of axial displacement, temperature and friction coefficient are obviously enhanced with the increase of rotation speed and axial pressure. It can also be found that the there exists rapid diffusion phenomenon in the Mg-Ti friction welding system. The large deformation activated diffusion coefficient is about 105 higher than that activated by thermal.

Lazard ss Elimination Process for Color Lie Superalgebras *

A pattern of Lazard*ss elimination theorem for color Lie superalgebras is proved.

升国旗

每周星期一的早晨,学校都要举行隆重而庄严的升国旗仪式。中午放学回家,欢欢的爸爸问欢欢:'今天学校举行升旗仪式时,你站在第几个呀?'欢欢对爸爸说:'我出个谜语让您猜吧.'欢欢说道:'三队同学来升旗,每队人数都一样。我的前面有9人,倒着数来我第六,您说共有多少人?'爸爸笑呵呵地说:'小家伙,还会出谜语,真不简单。

Some results on circular chromatic number of a graph

For two integers k and d with （k, d） = 1 and k≥2d, let G^dk be the graph with vertex set {0,1,…k - 1 } in which ij is an edge if and only if d≤｜ i -j I｜≤k - d. The circular chromatic number χc（G） of a graph G is the minimum of k/d for which G admits a homomorphism to G^dk. The relationship between χc（ G- v） and χc （G）is investigated. In particular, the circular chromatic number of G^dk - v for any vertex v is determined. Some graphs withx χc（G - v） =χc（G） - 1 for any vertex v and with certain properties are presented. Some lower bounds for the circular chromatic number of a graph are studied, and a necessary and sufficient condition under which the circular chromatic number of a graph attains the lower bound χ- 1 ＋ 1/α is proved, where χ is the chromatic number of G and a is its independence number.

Radius model of convex vertical curve of freeway based on attachment coefficient

A longitudinal slope brake model was established for the radius calculation of vertical curve of freeway through analyzing the dynamics of brake-running of vehicles running on the longitudinal slope road section. To satisfy the requirement of sight distance, a relation model was established for the attachment coefficient and the convex vertical curve radius. Using MATLAB simulation technique, the convex vertical curve radius at different attachment conditions was calculated accurately and a three-dimensional figure was drawn to describe the relation between the adhesive coefficient, the driving velocity and the radius of vertical curve. The correlation between the convex vertical curve radius and the adhesive coefficient was further analyzed and compared with National Technical Standards. The suggested radius of vertical curve was then put forward to provide a theoretical platform for the security design of the convex vertical curve.

Modified DIX model for ion-exchange equilibrium of L-phenylalanine on a strong cation-exchange resin

L-phenylalanine, one of the nine essential amino acids for the human body, is extensively used as an ingredient in food, pharmaceutical and nutrition industries. A suitable equilibrium model is required for purification of L-phenylalanine based on ion-exchange chromatography. In this work, the equilibrium uptake of L-phenylalanine on a strong acid-cation exchanger SH11 was investigated experimentally and theoretically. A modified Donnan ion-exchange （DIX） model, which takes the activiW into account, was established to predict the uptake of L-phenylalanine at various solution pH values. The model parameters including selectivity and mean activity coefficient in the resin phase are presented. The modified DIX model is in good agreement with the experimental data. The optimum operating pH value of 2.0, with the highest t-phenylalanine uptake on the resin, is predicted by the model. This basic information combined with the general mass transfer model will lay the foundation for the prediction of dynamic behavior of fixed bed separation process.

Extrathyroidal Implantation of Thyroid Hyperplastic/neoplastic Cells after Endoscopic Thyroid Surgery

Objective To report a case of the implantation of thyroid hyperplastic or neoplastic tissue after endoscopic thyroidectomy and discuss this complication in aspects of prevalence, pathogenesis, protection, and therapies. Methods A systematic search of literature from the PubMed database was conducted for identifying eligible studies on implantation of thyroid hyperplastic or neoplastic cells after endoscopic thyroid surgery. Results Overall, 5 reported cases on patients suffering from endoscopic thyroid surgery with implantation of thyroid hyperplastic or neoplastic cells were included in the systematic review. Conclusions Unskilled surgeons, rough intraoperative surgical treatment, scarification or rupture of tumor, contamination of instruments, chimney effect, aerosolization of tumor cells may be associated with the implantation after endoscopic thyroidectomy. To minimize the risk of such complication, we should be more meticulous and strict the endoscopic surgery indications.

Adjacent vertex-distinguishing total colorings of K_s∨K_t

Let G be a simple graph and f be a proper total kcoloring of G. The color set of each vertex v of G is the set of colors appearing on v and the edges incident to v. The coloring f is said to be an adjacent vertex-distinguishing total coloring if the color sets of any two adjacent vertices are distinct. The minimum k for which such a coloring of G exists is called the adjacent vertex-distinguishing total chromatic number of G. The join graph of two vertex-disjoint graphs is the graph union of these two graphs together with all the edges that connect the vertices of one graph with the vertices of the other. The adjacent vertex-distinguishing total chromatic numbers of the join graphs of an empty graph of order s and a complete graph of order t are determined.

Model of tri-sectional wheel-based cable climbing robot and analysis of centrifugal safety landing method

This paper proposes a new type of tri-sectional wheel-based cable climbing robot which is able to climb up vertical cylindrical cables of a cable-stayed bridge. The robot is composed of three pairs of wheels equally spaced circularly which are joined by six connecting boards to form a whole closed hexagonal body to clasp a cable. The whole design is entirely modular to enable to assenably the robot on-siteeasy eaoily. To analyze the static features of the robot, a mathematical model of climbing is deduced. Furthermore, taking a cable with a diameter of 80mm as an example, we calculate the design parameters of the robot. For safly landing in the case of electrical accident, a centrifugal speed regulator is proposed and applied to consume useless energy generated when the robot is slipping down along the cables. A simplified mathematical model of the landing mechanism is deduced. Finally, several experiments on the climbing mechanism demonstrate that the robot can carry payloads less than 2.2kg to climb up a cable with diameters varying from 65mm to 205mm.

Application of diffusive transport model for better insight into retardation mechanisms involved in ion-imprinted membrane transport

Heavy metal removal from water is a great concern for environmentalists and engineers. Ion-imprinted membranes are among the state of the art technologies for selective adsorption of heavy metals from aqueous environment. Dialysis permeation of nickel ions through Ni(II)-imprinted membranes has been thermodynamically studied in our prior work. In current study, the diffusive transport model was developed and then applied for better insight into the retardation mechanisms involved in the ion-imprinted membrane transport. The Sips isotherm model was coupled with the transport model to obtain the governing equation. Chemisorption and physical interactions(bulk diffusion and pore-clogging) were the most probable retardation mechanisms according to the modeling results. Relative retardation factor(η) was also defined as; transport-rate controlled by chemical adsorption to that controlled by physical interactions. With the help of the retardation factor, it was understood that the membrane behavior gradually changes from chemisorption to facilitated transport during permeation time. Effect of important operating parameters such as time, temperature and concentration on transport behavior was also investigated. Results indicated that chemisorption rate is rather higher at lower concentrations, early permeation times and reduced temperatures. In addition, η tabulated greater values for Ni(II) compared to Co(II) due to the imprinting effect.

Impact Dynamics on Granular Plate

In this paper, a theoretical and numerical study on the impact of a rubber solid on the free surface of a granular plate is presented, showing a simulation of an aircraft wheel on impact with a flexible landing surface. This physical action, when we use a theological approach, becomes a fundamental parameter to investigate wear and tear, and consequently strength to micro and macro pavements failure. The study has developed initially from a microscopic point of view and subsequently on macroscale. The effects are strictly linked with material degradation associated with damage evolution. The problem is developed by energetic approach on an elastic-plastic element using the functional energy containing two contributions, bulk and surface. The model simulates the behaviour of flexible runway pavements during the landing phase.

Experimental Evaluation of Thermal Properties of Grouting Materials

This study is aimed at the thermal analysis of sealant mortar （usually a mixtures of bentonite and cemem with addition of sand） used in geothermal cooling and heating. In particular, thermal conductivity and diffusivity measurements were performed on differem sealant mixtures by using Hot Disk thermal constants analyzer in order to identify the interesting thermal properties of grouting materials. The grouting materials that we considered are of porous nature and, if used in the presence of groundwater, have different levels of imbibitions. It is important to know the thermal behavior of these materials at different water content. A first set of measurements was performed on a not-tinted material at room temperature; then the samples were led to saturation conditions by contact capillary imbibitions with a cotton wool layer moistened in water. The determination of thermal conductivity in these test conditions appears to be critical compared to the measuremems on non-timed sample. The thermal conductivity tests have revealed how the thermal behavior of the samples analyzed is essentially determined by the density and water content of the material： in fact, the thermal conductivity increases of two to three times the value of the not-tinted material.

如何教会孩子数数

数数是低年级学生学习数学的一项基本技能。数数要求顺着数、倒着数、跳着数,在数数教学中隐含着规律教学和乘除法的教学。数数的教学要求老师必须采取一定的方式去引导学生养成习惯。