电子信息类实验教学对学生关联力培养的研究

关联力是“新工科”培养的未来工程师应该具备的重要素质,本文研究了电子信息类实验教学如何提升学生关联力的问题,重点从知识空间、虚拟空间、人际交往空间关联几方面展开探索与实践。基于成果导向教育理念及关联主义理论,设计了一种螺旋关联的电子信息综合实验体系,促进学生跨学期知识体系的贯通性、能力发展的连续性;借鉴现代自由学习理论、关联主义理论,形成了一种“虚实融合、师生学习共同体”实验教学方法,强调跨时空关联、师生关联,促进关联力的逐步提升。学生能力培养最终的落脚点在于评价,给出了一种“关联能力导向式、教师全过程评价、学生自评与互评”融合的实验教学评价方法,将学生行为级别的评价转化为能力级别的评价,更利于实验教学的持续改进。

色关联随机力作用下吸积盘振荡光度的功率密度谱

采用受色关联随机力作用下的广义朗之万方程描述黑洞吸积盘的垂向振荡,推导得到吸积盘随机振荡的光度和功率密度谱,并分析了黑洞双星系统参数对功率谱曲线的影响.研究结果表明:当选取适当系统参数时,功率密度谱曲线上会出现随机共振现象;随机力的关联时间、吸积盘的吸积率和粘滞系数决定随机共振强弱,但共振峰位置只随黑洞质量不同而发生变化.

钢丝绳高速回撤的动力学建模与仿真

右旋顺捻钢丝绳在高速回撤过程中会发生右偏现象,钢丝绳在回撤末期剧烈甩动,存在缠绕滑轮和损坏周边设备的安全隐患。为评估钢丝绳在回撤过程中的风险,指导回撤轨迹规划算法设计,以多体动力学为基础建立了钢丝绳回撤过程的运动仿真模型。首先,根据“质量-弹簧-阻尼”模型,推导出钢丝绳的张力;然后,在假设钢丝绳摩擦因子有各向异性特征的条件下,建立了各向异性摩擦力学模型,分析右旋顺捻钢丝绳的右偏现象;再次,将绳丝等效为柔性梁,根据捻制钢丝绳的抗弯刚度模型推导了钢丝绳的弯矩;最后,将所有物理特性集中于节点,通过牛顿第二定律与运动学方程得到各节点的运动轨迹,并基于所建立的钢丝绳回撤运动仿真模型,分别对右旋顺捻钢丝绳和右旋交互捻钢丝绳在两种不同速度轨迹规划下的回撤过程进行了仿真分析。分析结果与试验现象相符,初步验证了所建模型的正确性。

关注“四力”培养 突破解题之困

“读、联、写、思”是学习思想政治的基本功,更是考试解题拿高分的关键能力。文章从“读得懂、想得到、写得清、说得透”角度,结合教学实践论证思想政治主观题的解题要领,提出关注阅读力、重视关联力、训练表达力、强化逻辑力的策略,帮助学生破解主观题解题密码。

加密刑事电子数据证据之关联性判断

证据的关联性具有双重含义:一是证据有能力证明案件事实,此为证据能力关联性;二是证据与案件事实之间具有实质关联性,此为证据证明力关联性。在证据能力关联性方面,加密刑事电子数据证据搜查范围与加密电子数据信息与案件信息的关联性程度相关。密码与加密电子数据信息宜并列成为刑事搜查的对象。未来立法有必要构建完善的密码提供商协助执法机构义务规则及密码搜查规则以消解加密技术导致的惩罚犯罪与保障人权之间的内在冲突。在证明力方面,加密技术将影响司法主体对加密刑事电子数据证据证明力内容的认知,并推动关联性审查判断方法的更新换代。加密技术要求在加密刑事电子数据证据证明力关联性层面以搭建虚拟与现实空间的关联性判断规则为基础,构建中间性事实与司法者背景知识的关联性判断制度。如此可有效消解法庭争议,提升司法裁判的权威。

新工科背景下工程合同管理课程教学改革

高等教育教学研究的目的就是提高教学质量。在新工科背景下,进行工程合同管理课程教学改革势在必行。新工科理论要求培养新素养的人才,培养学生“超世界”的使命感、价值感,构建学生“问题空间“”社会空间”的空间感,注重学生多学科、多专业的关联力,发展丰富的想象力宏思维。文章对此进行教学改革探索。

Analysis of Driving Factors of Grain Output in Henan Province Based on Grey Correlation Model

Henan Province is an important grain production base, whose stable production is related to the economic development and social stability significantly. To summarize the primary factors of grain producing, we used grey correlation analysis method to analyze 10 correlative factors such as grain yield, grain yield per unit area, effective irrigated area, rural employed persons, grain planting area, consumption of chemical fertilizer in 25 years. The results showed order of synthetic degree of incidence: effective irrigated area>rural electricity consumption>consumption of chemical fertilizer>disaster crop area>grain yield per unit of area>total power of agricultural machinery>afflicted crop area>grain planting area>number of the rural employed persons. Finally, according to synthetic degree of incidence between influential factors and total grain output respectively, a series of measures and the suggestions was proposed for grain production in Henan Province, which will also provide the scientific basis and help for the government correct decision-making.

Deformation mechanism of high-stress and broken-expansion surrounding rock and supporting optimization based on the gray correlation theory

Aiming at the large deformation and support problems of high-stress and broken-expansion surrounding rock, and taking 1 000 m level roadway of Mine II in Jinchuan as the research object, an investigation on the deformation and damage of roadway surrounding rock and an analysis of its mechanism were carried out. The gray correlation theory was used in support scheme optimization design. First, causes and mechanism of deformation of the 1 000 m horizontal transport channel were analyzed through field investigation, laboratory test and data processing methods. We arguued that poor engineering geological conditions and deep pressure increases were the main factors, and the deformation mechanism was mainly the ground deformation pressure. Second, the gray correlation theory was used to construct supporting optimization decision method in the deep roadway. This method more comprehensively considers various factors, including construction, costs, and supporting material functions. The combined support with pre-stressed anchor cables, shotcrete layer, bolt and metal net was put forward according to the actual roadway engineering characteristics. Finally, 4 support schemes were put forward for new roadways. The gray relational theory was applied to optimizing the supporting method, undertaking technical and economic comparison to obtain the correlation degree, and accordingly the schemes were evaluated. It was concluded as follows： the best was the flexible retaining scheme using the steel strand anchor; the second best was the one using plate anchors on the top and rigid common screw steel bolt on the two sides; the ttiird was; the rigid common screw steel bolt in full section of roadway; and the worst is the planished steel rigid support. The optimized scheme was applied to the 1000 m level of new excavation roadway. The results show that the roadway surrounding rock can reach a stable state after 5 to 6 months monitoring, with a convergence rate less than 1 mm/d.

COMPLEXITY AND CHAOTIC DYNAMICS OF ROCK FAULTING

Fault is a complex dynamic system controlled by the coupling of rock texture, reaction, fluid flow,stress, and rock deformation mechanism. A coupled reaction-transport- mechanical dynamic model for fault system is established and described in this paper. An example is presented for the Shuikoushan deposit, Hunan. The results of dynamic simulation indicate that the evolution and magnitude of fracture permeability of different rocks are different, and that faulting can enhance the spatial heterogeneity of rock permeability and facilitate fluid flow and mineralization in local fault zone. The pressure for a fault usually shows a variation mode of aperiodic oscillation with time, which reflects the chaotic behavior of the evolution of a fault.

Elastodynamic modeling and joint reaction prediction for 3-PRS PKM

To gain a thorough understanding of the load state of parallel kinematic machines(PKMs), a methodology of elastodynamic modeling and joint reaction prediction is proposed. For this purpose, a Sprint Z3 model is used as a case study to illustrate the process of joint reaction analysis. The substructure synthesis method is applied to deriving an analytical elastodynamic model for the 3-PRS PKM device, in which the compliances of limbs and joints are considered. Each limb assembly is modeled as a spatial beam with non-uniform cross-section supported by lumped virtual springs at the centers of revolute and spherical joints. By introducing the deformation compatibility conditions between the limbs and the platform, the governing equations of motion of the system are obtained. After degenerating the governing equations into quasi-static equations, the effects of the gravity on system deflections and joint reactions are investigated with the purpose of providing useful information for the kinematic calibration and component strength calculations as well as structural optimizations of the 3-PRS PKM module. The simulation results indicate that the elastic deformation of the moving platform in the direction of gravity caused by gravity is quite large and cannot be ignored. Meanwhile, the distributions of joint reactions are axisymmetric and position-dependent. It is worthy to note that the proposed elastodynamic modeling method combines the benefits of accuracy of finite element method and concision of analytical method so that it can be used to predict the stiffness characteristics and joint reactions of a PKM throughout its entire workspace in a quick and accurate manner. Moreover, the present model can also be easily applied to evaluating the overall rigidity performance as well as statics of other PKMs with high efficiency after minor modifications.

Evaluation of Relationship Between Clothing Pressure of Men's Suit and Comfort

An investigation on relationship between clothing pressure of men's suit and wearing comfort is conducted. With the pressure measurements at different parts of men's suit under normal standing posture and in motion, the objective assessment of the total comfort are related to the subjective ratings of clothing pressure. There is a common strong sensation of pressure on shoulder with normal standing posture, and a strong relationship between total comfort and clothing pressure in back armhole and the front of upper arm with posture in motion.

Two Types of Arctic Oscillation and Their Associated Dynamic Features

In this paper,the dynamical evolutions of two types of Arctic Oscillation (AO),the stratospheric (S) and tropospheric (T) types,have been investigated on an intermediate time scale in terms of transient eddy feedback forcing and three-dimensional Rossby wave propagation.S-Type (T-type) events are characterized by an anomalous stratospheric polar vortex that is in phase (out of phase) with its tropospheric counterpart.Approximately onethird of AO events,both positive and negative,are T-type events.For the positive phase of a T-type event,the formation and maintenance of stratospheric positive anomalies over the polar cap are associated with an upward propagation of Rossby wave packets originating from the near-tropopause altitude over northeastern Asia.However,such upward propagating features are not found for S-type events.In the troposphere,transient eddy feedback forcing is primarily responsible for the meridional seesaw structure of both the S-and T-type events,with an additional contribution from Rossby wave propagation.

Measurement and correlation of solid-liquid equilibrium data for nitroguanidine in water and organic solvents from 298.15K to 338.15K

Nitroguanidine（NQ） isa high energy and low sensitivity explosive and solid-liquid equilibrium data are significant for study on crystallization of NQ. The solubilities of NQ in water, dimethyl sulfoxide, N, N dimethylformamide, 1,4 butyrolaetone and dimethyl sulfoxide @ water, N, N dimethylformamide ＋ water were measured by dynamic laser monitoring within a temperature range from 298. 15 K to 338. 15 K. The experimental data were correlated by modified Apelblat equation, 2h equation, CNIBS/R K model, andJouyban-Acree model. The results show that the four thermodynamic models can all be used to predict solubility with high accuracy. Accrding to the Akaike＇s information criterion （AIC）, the better models for correlating the solubility of NQ are judged. Additionally, the dissolution enthalpy, entropy and Gibbs free energy were calculated by the van＇t Hoff equation.

Anomalous Dissipative Quantum Harmonic Oscillator

We investigate the low-temperature statistical properties of a harmonic oscillator coupled to a heat bath, where the low-frequency spectrum vanishes. We obtain the exact result of the zero point energy. Due to the low frequency shortage of environmental oscillators＇ spectral density, the coordinate and momentum correlation functions decay as T^-4 arid T^-6 respectively at zero temperature, where T is the correlation time. The low-temperature behavior of the mean energy does not violate the third law of thermodynamics, but differs largely from the Ohmic spectrum case.

Improved slope safety analysis by new Druker-Prager type criterion

Based on Mohr-Coulomb （M-C） criterion, the parameters of Druker-Prager （D-P） criterion for geomaterial were determined under non-associated flow rule, and thus a new D-P type criterion was presented. Two assumptions were employed during the derivation： 1） principal strains by M-C model and D-P model are equal, and 2） the material is under plane strain condition. Based on the analysis of the surface on rt plane, it is found that the proposed D-P type criterion is better than the D-P criterion with M-C circumscribed circle or M-C inscribed circle, and is applicable for stress Lode angle less than zero. By comparing the predicted results with the test data of sand under plane strain condition and other D-P criteria, the proposed criterion is verified and agrees well with the test data, which is further proved to be better than other D--P type criteria in certain range of Lode angle. The criterion was compiled into a finite difference package FLAC3D by user-subroutine, and was used to analyze the stability of a slope by strength reduction method. The predicted slope safety factor from the proposed criterion agrees well with that by Spencer method, and it is more accurate than that from classic D-P criteria.

Can coordination variability identify performance factors and skill level in competitive sport? The case of race walking

Background:Marginal changes in the execution of competitive sports movements can represent a significant change for performance success.However,such differences may emerge only at certain execution intensities and are not easily detectable through conventional biomechanical techniques.This study aimed to investigate if and how competition standard and progression speed affect race walking kinematics from both a conventional and a coordination variability perspective.Methods:Fifteen experienced athletes divided into three groups(elite,international,and national) were studied while race walking on a treadmill at two different speeds(12.0 and 15.5 km/h).Basic gait parameters,the angular displacement of the pelvis and lower limbs,and the variability in continuous relative phase between six different joint couplings were analyzed.Results:Most of the spatio-temporal,kinematic,and coordination variability measures proved sensitive to the change in speed.Conversely,non-linear dynamics measures highlighted differences between athletes of different competition standard when conventional analytical tools were not able to discriminate between different skill levels.Continuous relative phase variability was higher for national level athletes than international and elite in two couplings(pelvis obliquity—hip flex/extension and pelvis rotation—ankle dorsi/plantarflexion) and gait phases(early stance for the first coupling,propulsive phase for the second) that are deemed fundamental for correct technique and performance.Conclusion:Measures of coordination variability showed to be a more sensitive tool for the fine detection of skill-dependent factors in competitive race walking,and showed good potential for being integrated in the assessment and monitoring of sports motor abilities.

Measurement and Correlation of Pressure Drop for Gas-Liquid Two-phase Flow in Rectangular Microchannels

The pressure drop of gas-liquid two-phase flow in microchannel is of fundamental importance in heat and mass transfer processes. In this work,the pressure drop of gas-liquid two-phase flow in horizontal rectangular cross-section microchannels was measured by a pressure differential transducer system. Water,ethanol and n-propanol were used as liquid phase to study the effects of capillary number on pressure drop;air was used as the gas phase. Four microchannels with various dimensions of 100 μm× 200 μm,100 μm× 400 μm,100 μm× 800 μm and 100 μm× 2000 μm(depth × width) were used for determining the influence of configuration on the pressure drop. Experimental results showed that in micro-scale,the capillary number also affected the pressure drop remarkably,and in spite of only one-fold difference in aspect ratio,the variation of pressure drop reached up to near three times under the same experimental conditions. Taking the effects of aspect ratio and surface tension into account,a modi-fied correlation for Chisholm parameter C in the Chisholm model was proposed for predicting the frictional multi-plier,and the predicted values by the proposed correlation showed a satisfactory agreement with experimental data.

Criterion of Quantum Entanglement and the Covariance Correlation Tensor in the Theory of Quantum Network

This article discusses the covariance correlation tensor (CCT) in quantum network theory for four Bell bases in detail. Furthermore, it gives the expression of the density operator in terms of CCT for a quantum network of three nodes, thus gives the criterion of entanglement for this case, i.e. the conditions of complete separability and partial separability for a given quantum state of three bodies. Finally it discusses the general case for the quantum network of nodes.

Functional Connectivity Difference Detected in Bilateral Occipital Lobes Between the Abacus Experts and Control Groups: Using Nonlinear Processing Method

Objective:This paper is to investigate functional connectivity differences between the abacus experts and control groups by using nonlinear processing method spatiotemporal Lyapunov exponent.Methods:11 right-handed healthy control children and 12 abacus children were undergone functional magnetic resonance imaging(fMRI).After preprocessing fMRI data with SPM,linear and nonlinear methods for connectivity analysis were both employed.Results:Connectivity differences between the two groups were statistically P<0.05 by the correlation method,while the P value by the nonlinear method were P<0.01.Conclusion:There are significant differences between the two groups in functional connectivity of bilateral occipital lobes.The nonlinear method proposed here seems to be more specific compared with the common linear correlation method.

Understanding Molecular Dynamics with Stochastic Processes via Real or Virtual Dynamics

Molecular dynamics with the stochastic process provides a convenient way to compute structural and thermodynamic properties of chemical, biological, and materials systems. It is demonstrated that the virtual dynamics case that we proposed for the Langevin equation [J. Chem. Phys. 147, 184104 （2017）] in principle exists in other types of stochastic thermostats as well. The recommended ＂middle＂ scheme [J. Chem. Phys. 147, 034109 （2017）] of the Andersen thermostat is investigated as an example. As shown by both analytic and numerical results, while the real and virtual dynamics cases approach the same plateau of the characteristic correlation time in the high collision frequency limit, the accuracy and efficiency of sampling are relatively insensitive to the value of the collision frequency in a broad range. After we compare the behaviors of the Andersen thermostat to those of Langevin dynamics, a heuristic schematic representation thermostatting processes with molecular is proposed for understanding efficient stochastic dynamics.