构建四维一体的会计类专业实训体系

本文针对会计类专业顶岗实训困难的问题,在总结多年课程建设经验的基础上,提出两种模式四维一体的校内实训体系来实现会计类专业工学结合的顶岗实习,并提出了博弈性的会计职业岗位仿真实训的设想。

浅谈高职《计算机组装与维修》课程教学

在高职《计算机组装与维修》教学中,注重学生能力的培训,用多媒体与网络化教学手段来创新教学,验证性实验实训与社会实践相结合,选用合适的教材,注重实践能力的考核,不断提高教学效果。

基尔霍夫定律的信息化教学设计

本论文针对《电工电子技术》课程理论教学枯燥无趣、教学效果差的目前现状,从教学内容、教学策略、教学过程、教学反思四个方面进行了深刻的总结与探讨,提出了利用现代信息技术,采用先进的信息化手段辅助教学过程的教学理念,培养学生对理论知识学习的浓厚兴趣。

Alternate operation characteristics of a solar-ground source heat pump system

In order to investigate the alternate operation characteristics of a solar-ground source heat pump system（SGSHPS）,various alternate operation modes are put forward and defined.A two-dimensional mathematical model with freezing/melting phase changes is developed for the heat transfer analysis of the soil.Based on the numerical solution of the model,the variation trends of underground soil temperature of the SGSHPS operated in various alternate operation modes are discussed.The results indicate that,for the day-night and short-time interval alternate operation modes without solar energy,the operation time fraction of a solar heat source should be confined to from 50% to 58% when operated in an alternate period of 24 h.Meanwhile,the disadvantages of a natural resumption of soil temperature can be overcome effectively by solar energy filling,and an optimal operation effect can be achieved by integrating the mode of solar energy filling with other alternate modes.In addition,the accuracy of the presented model is verified by the experimental data of borehole wall temperatures.The conclusions can provide a reference for the optimization operation of the SGSHPS.

Lifetime prediction for tantalum capacitors with multiple degradation measures and particle swarm optimization based grey model

A lifetime prediction method for high-reliability tantalum （Ta） capacitors was proposed, based on multiple degradation measures and grey model （GM）. For analyzing performance degradation data, a two-parameter model based on GM was developed. In order to improve the prediction accuracy of the two-parameter model, parameter selection based on particle swarm optimization （PSO） was used. Then, the new PSO-GM（1, 2, co） optimization model was constructed, which was validated experimentally by conducting an accelerated testing on the Ta capacitors. The experiments were conducted at three different stress levels of 85, 120, and 145℃. The results of two experiments were used in estimating the parameters. And the reliability of the Ta capacitors was estimated at the same stress conditions of the third experiment. The results indicate that the proposed method is valid and accurate.

Verification of Seismic Performance of Pile Foundation in Composite Ground through Experimental and Numerical Methods

A new construction method of pile foundation in composite ground, in which, prior to installing piles, the ground is improved around the heads of the piles in soft ground or ground subject to liquefaction, which is introduced in this paper. This construction method uses a combination of pile foundation construction together with common ground improvement methods, including deep mixing, preloading and sand compaction piling, and it is referred to as the composite ground pile method. Since an artificial ground with relatively high rigidity comparing with that of the original ground was formed around the pile in this method, and the seismic performance has not been made clear, thus the seismic performance of piles in composite ground was systematically analyzed through a series of centrifuge model tests and numerical analyses by using dynamic nonlinear finite element method, and a verification method for the seismic performance of piles in composite ground was proposed on the basis of the experimental and numerical results.

Upper bound solutions for supporting pressures of shallow tunnels with nonlinear failure criterion

Linear failure criterion is widely used in calculation of earth pressure acting on shallow tunnels. However, experimental evidence shows that nonlinear failure criterion is able to represent fairly well the failure of almost all types of rocks, A nonlinear Hock-Brown failure criterion is employed to estimate the supporting pressures of shallow tunnels in limit analysis framework. Two failure mechanisms are proposed for calculating the work rate of extemal force and the internal energy dissipation. A tangential line to the nonlinear failure criterion is used to formulate the supporting pressure problem as a nonlinear programming problem. The objective function formulated in this way is minimized with respect to the failure mechanism and the location of tangency point. In order to assess the validity, the supporting pressures for the proposed failure mechanisms are calculated and compared with each other, and the present results are compared with previously published solutions when the nonlinear criterion is reduced to linear criterion. The agreement supports the validity of the proposed failure mechanisms. An experiment is conducted to investigate the influences of the nonlinear criterion on collapse shape and supporting pressures of shallow tunnels.

Intra-Palm Propagation Signals as Suitable Biometrics for Successive Authentication

We propose the use of intra-palm propagation signals as biometrics. The intra-palm propagation signal is a signal that is propagated in the shallow part of the skin of a palm. In this paper, we prepare dedicated measuring devices and measure intra-palm propagation signals from twenty-one experimental subjects. We also evaluate the verification performance based on Euclidian distance or SVM （support vector machine）. The equal error rate in the case of SVM is aovroximatelv 24%.

Optimization Algorithm for Operation Comfortability of Master Manipulator of Minimally Invasive Surgery Robot

To evaluate the operation comfortability in the master-slave robotic minimally invasive surgery(MIS), an optimal function was built with two operation comfortability decided indices, i.e., the center distance and volume contact ratio. Two verifying experiments on Phantom Desktop and Micro Hand S were conducted. Experimental results show that the operation effect at the optimal relative location is better than that at the random location, which means that the optimal function constructed in this paper is effective in optimizing the operation comfortability.

加强实验室管理,提高教学质量

高职高专不同于一般普通本科院校的区别在于,重视培养大学生的实践动手能力。实验教学是高职高专院校教学体系中不可忽视的重要内容,对培养职业技术学院的大学生创新能力、综合素质意义重大。目前我们的实验教学还存在着许多薄弱环节,如何提高实验教学的质量是广大实验教师长期所探讨的问题。根据本人多年的实验教学实践,总结一些经验心得和同行们一起探讨。

新课改下初中物理实验教学的探讨

物理是一门以实验为基础的学科,在新课改实施的背景下,实验教学在物理教学中具有十分重要的作用。在目前所使用的新教材中,实验教学几乎贯穿于整个教学过程,物理实验作为一种理论联系实际的实践活动,它使学生处于教学的主要地位。灵活地运用知识并促成知识的迁移,用生动、形象的实验过程启发学生,激发学生的学习兴趣。

High flowrate injector with gaseous hydrogen and gaseous oxygen

In order to get a high flowrate gas-gas injector and its design methodology, the combustion flow field of a typical shear-coaxial injector was analyzed firstly. The dimensional analysis was applied in the phenomenon of gas-gas combustion, and design parameter optimization and a structure improvement were also carded out. A high flowrate single-element injector with high 1-12/O2 momentum ratio and tapered 02 post tip was obtained and validated by both numerical and experimental studies. This high flowrate injector has simple construction and it can effectively enhance the mixing, decrease the combustion completion length and also has a benign heat environment. Furthermore, based on the study of the single-element injector, numerical optimization and validation experiments were conducted successively on a multi-element injector equipped with high flowrate injection elements. The multi-element injector with the high flowrate elements started up and shut down smoothly, and operated steadily without any stability aids. In the combustor designed with nominal parameters, this injection element can obtain high combustion efficiency with a flowrate of 3.7 times that of SSME main injector element and shows a benign chamber wall heat compatibility. This injector design and the design methodology can become a reference for the design of other types of injectors for liquid rocket engines.

A new route for length measurement by phase-shifting interferometry

By the mathematic models of flexible hinge,the accurate relationship between the phase-shifting and pressure acting on the hinge is deduced and verified by experimental results.Through the optimization of the geometric parameter of flexible hinge,a phase-shifting generator is developed to determine the length of an object precisely by interferometry.The experiments show that the triple phase-shifting produced using this generator is up to 1 m.With this generator,an example for the application in length measurement is introduced.The result shows the length uncertainty is 0.5 nm when the temperature uncertainty is limited in 2 mK.This paper provides a novel technique to measure the dimension of an object,especially to the diameter of a silicon sphere for Avogadro constant project.

Experimental evidence for non-linear growth in compressible mixing layer

An experimental study of compressible mixing layers(CMLs)was conducted using planar laser Mie scattering(PLMS)visualizations from condensed ethanol droplets in the flow.Large ensembles of digital images were collected for two flow conditions at convective Mach numbers Mc=0.11 and 0.47.The coherent vortices,braids and eruptions in the mixing zone were observed,interpreted as evidence of multi-scale,three-dimensional structures at a high Reynolds number.The mixing layers with a large visualized range present two stages along the streamwise direction,corresponding to the initial mixing and the well-developed stage.A new method,the gray level ensemble average method(GLEAM),by virtue of the similarity of the mixing layer,was applied to measure the growth rate of the CML thickness.New evidence for a nonlinear growth of CML is reported,providing an interpretation of previous observations of the scattering of the growth rate.

Opposed elevational variation in prevalence and intensity of endoparasites and their vectors in a lizard

Studying the causes of parasite geographic distribution is relevant to understand ecological and evolutionary processes that affect host populations as well as for species conservation. Temperature is one of the most important environmental variables affecting parasite distribution, as raising temperatures positively affect development, reproduction, and rate of transmission of both endo- and ectoparasites. In this context, it is generally accepted that, in mountains, parasite abundance decreases with elevation. However, empirical evidence on this topic is limited. In the present study, we analyzed the elevational variation of hemoparasites and ectoparasites of a lizard, Psammodromus algirus, along a 2,200-m elevational gradient in Sierra Nevada （SE Spain）. As pre- dicted, ectoparasite （mites, ticks, mosquitoes, and sandflies） abundance decreased with elevation. However, hemoparasite prevalence and intensity in the lizard augmented with altitude, showing a pattern contrary to their vectors （mites）. We suggest that tolerance to hemoparasites may increase with elevation as a consequence of lizards at high altitudes taking advantage of increased body condition and food availability, and reduced oxidative stress. Moreover, lizards could have been selected for higher resistance against hemoparasites at lowlands （where higher rates of replication are expected）, thus reducing hemoparasite prevalence and load. Our findings imply that, in a scen- ario of climate warming, populations of lizards at high elevation may face increased abundance of ectoparasites, accompanied with strong negative effects.

No evidence for female discrimination against male house mice carrying a selfish genetic element

Meiotic drivers distort transmission to the next generation in their favor, with detrimental effects on the fitness of their homologues and the rest of the genome. Male carriers of meiotic drivers commonly inflict costs on their mates through genetic incompatibility, reduced fecundity, or biased brood sex ratios. Given these costs, evidence for female discrimination against male carriers is surprisingly rare. One of few examples is the t haplotype in house mice, a meiotic driver that shows strong transmission distortion in males and is typically homozygote lethal. As a consequence, mating between 2 t heterozygous （＋/t） mice leads to high embryo mortality. Previous experiments showing that＋/t females avoid this incompatibility cost by preferring ＋/＋ versus ＋/t males have inferred preference based on olfactory cues or brief social interactions. Evidence from mating contexts in laboratory settings and semi-natural populations has been inconclusive. Here, we investigated female choice from a large number of no-choice mating trials. We found no evidence for discrimination against＋/t males based on mating, remating, and copulatory behavior. Further, we found no evidence for avoidance of incompatibility through selective interactions between game- tes. The likelihood of mating showed significant effects of female weight and genotype, suggesting that our test paradigm enabled females to exhibit mate choice. We discuss the strengths and limitations of our approach. By explicitly considering selection at both the individual and gene level, we argue why precopulatory female discrimination by＋/t females may be less evolutionarily stable than discrimination by all females based on postcopulatory mechanisms.

Experimental demonstration of concatenated composite pulses robustness to non-static errors

We examine the robustness of composite pulses to non-static classic noise in the NMR facility. Though these pulses are proposed to eliminate static, systematic errors, they are shown to be robust to time-varying noise with high-cut frequency up to near 10% of the Rabi frequency in a recent theoretical work. The CP pulses that are only robust to one kind of error have been implemented in various experiment platforms. In this paper we have compared the performance of reduced CinSK rc pulse, which is designed to cancel both the pulse length error and the off resonance error, to that of the primitive n pulse in a hybrid error environment. In order to achieve this target we have simultaneously injected noise to the RF output wave. The filter function formalism is employed to predict the evolution fidelity decay, which shows great consistency with the experiment data. Our work not only validates the superiority of reduced CinSK pulse but also indicates its sensitivity to the initial states, providing practical guidance in the noise suppression domain.

From electronic excited state theory to the property predictions of organic optoelectronic materials

We introduce here a work package for a National Natural Science Foundation of China Major Project. We propose to develop computational methodology starting from the theory of electronic excitation processes to predicting the opto-electronic property for organic materials, in close collaborations with experiments. Through developing methods for the electron dynamics, considering superexchange electronic couplings, spin-orbit coupling elements between excited states, electron-phonon relaxation, intermolecular Coulomb and exchange terms we combine the statistical physics approaches including dynamic Monte Carlo, Boltzmann transport equation and Boltzmann statistics to predict the macroscopic properties of opto-electronic materials such as light-emitting efficiency, charge mobility, and exciton diffusion length. Experimental synthesis and characterization of D-A type ambipolar transport material as well as novel carbon based material will provide a test ground for the verification of theory.