鼠疫耶尔森菌株间遗传关系的数值化分析

目的 :显示不同鼠疫菌株之间的遗传学关系。方法 :将鼠疫菌株间的相似程度数值化 ,进行聚类分析。结果 :检验菌株可以聚为 2个亚种 4个型。结论 :由一次流行而生的型彼此间相似程度较高 ,因各固有疫源地而生的型 ,其间的差异更为显著。

地铁上盖建筑物下的岩土工程与数值化分析

以深圳蔡屋围基坑工程为典型案例,深刻揭示了在地铁隧道上方进行基坑支护与土方开挖的复杂性与挑战性。由于该项目上穿地铁隧道,将面临着一系列技术难题和安全风险。为此,采用数值化分析手段,以便精准预测开挖时地铁隧道结构的应力和变形状态,确保工程安全可控。在施工中严格遵循既定方案,并辅以严密的监测措施,旨在最大限度地减轻对周边环境和地铁轨道的潜在影响。最终,成功实现了基坑的安全开挖,确保了地铁运行和周边建筑的安全。蔡屋围基坑工程的成功实施,验证了本技术方案和施工工艺的可行性,可为类似工程项目提供经验借鉴。

镉-钙黄绿素配合物在玻片表面的毛细流成环组装及其数值化荧光成象分析研究

一滴撒落在固载表面上的咖啡干涸后, 会在原始液滴周边形成一个清晰的沉积环. 这种环沉积(Ring deposit)现象在其它液滴(如牛奶、 泥浆等)干涸过程中十分普遍. Deegan[1,2]等认为这是由于发生在液滴内部的毛细流作用(Capillary flow effect) 所致. 与电场和磁场一样, 毛细流传输作用对溶质分子在固载表面的固定化组装具有定向作用(Direction effect), 因而可以用于探针分子在固载表面的组装及其分析应用研究[3]. 同时, 毛细流定向组装成环技术需要样品少, 灵敏度高, 在生化研究及分析、 临床检验和环境监测方面具有十分重要的应用前景.

甘薯天蛾幼虫体色分化动态的数值化评价指标及其应用

为解决无法用文字实现对近千种连续变化的昆虫体色进行准确的描述和合理的数学运算问题,本文采用国际标准颜色计量技术-PFG(Pantone Formula Guide)颜色指南为昆虫体色性状判别标准,提出了关于数值化描述昆虫体色的相关评价指标,如体色元(body-colorelement,BCE)、体色群(body-color group,BCG)、体色位(body-colorposition,BCP)、高频色码指数(high frequency color-code index,HFI)和杂色指数(variegated color index,VCI)等及其定量分析方法。并应用这些指标和方法,研究了甘薯天蛾Agrius convolvuli幼虫个体在相似环境条件下体色分化的多样性以及不同发育日龄和不同虫体部位(体位)其体色的演化过程及其数值规律,发现甘薯天蛾幼虫存在着共同的主体色,而且其体色的变异主要发生在个体的不同发育日龄(占总变异的72.66%),其次,虫体不同部位的颜色也有明显的差异(占总变异的24.45%),而同一发育日龄个体间的体色差异仅占总变异的2.88%。结果说明,甘薯天蛾幼虫体色随其发育日龄所发生的变化过程,可能是由遗传因子所决定的一种生命体从发育到衰老的表观呈现过程。

关节机器人用偏心削极SPMSM气隙磁场解析计算及可视化平台研究

采用子域法对表贴式永磁同步电机(SPMSM)进行建模,对电机内部磁场进行解析计算。针对传统子域法无法应用于采用偏心削极结构的SPMSM的问题,对不等厚偏心削极的永磁体子域,提出等面积分块的处理方式,将每个磁极块单独进行解析计算。将线性叠加结果与有限元法和实验结果进行对比,结果表明所提方法有较高的计算精度。此外,将不同种类电机及子域建模方法进行整合,建立用户交互平台,使计算过程可视化,为国产化工程应用软件提供可扩展性,辅助电机设计与分析工作。

基于ANSYS的铝合金厚板淬火过程热力耦合数值分析

基于ANSYS的参数化设计语言和用户界面设计语言,建立铝合金厚板淬火过程的热力耦合分析模型,实现模型的参数化和分析过程的流程化,探讨铝合金厚板在淬火过程中的应力变化和淬火后的残余应力分布规律。研究结果表明:在淬火过程中,铝合金厚板面部金属经历了由受拉状态到受压状态的转变,心部金属经历了从受压状态到受拉状态的转变,残余应力具有面部为压应力、心部为拉应力的空间分布特征;残余应力随着铝合金板厚度的增加而增大,当厚度增加到一定值(80 mm)时,厚度的增加对残余应力的影响不明显;残余应力随表面换热系数的增加而增加,表明通过改进淬火工艺能获得较小残余应力;以铝合金板与冷却水间的热交换达到平衡时的时间作为时间步,适合于铝合金厚板热力耦合作用过程的分析计算。

Operation optimization of prefabricated light modular radiant heating system:Thermal resistance analysis and numerical study

The utilization of prefabricated light modular radiant heating system has demonstrated significant increases in heat transfer efficiency and energy conservation capabilities.Within prefabricated building construction,this new heating method presents an opportunity for the development of comprehensive facilities.The parameters for evaluating the effectiveness of such a system are the upper surface layer’s heat flux and temperature.In this paper,thermal resistance analysis calculation based on a simplified model for this unique radiant heating system analysis is presented with the heat transfer mechanism’s evaluation.The results obtained from thermal resistance analysis calculation and numerical simulation indicate that the thermal resistance analysis method is highly accurate with temperature discrepancies ranging from 0.44℃ to−0.44℃ and a heat flux discrepancy of less than 7.54%,which can meet the requirements of practical engineering applications,suggesting a foundation for the prefabricated radiant heating system.

基于预拉伸工艺的铝合金厚板残余应力消除机理

基于有限元软件MSC.Marc,对7075铝合金厚板淬火过程和预拉伸过程进行参数化模拟。以淬火残余应力作为初始条件读入预拉伸模型,利用生死单元技术,对预拉伸机夹具的夹紧和放松进行模拟,并对拉伸机理进行研究。研究结果表明:在拉伸过程中,表层金属应力由受压逐渐变为拉应力,而内层金属一直受拉应力作用,松开夹具后,铝合金厚板回弹,应变出现松弛,应力大大减小;随着拉伸量的增加,残余应力随之减小;而塑性变形随之增加;当拉伸量相同时,残余应力随铝合金板厚的增加而增加,为达到消除残余应力的最佳效果,预拉伸量需随板厚的增加而增加;在满足应力消除效果的前提下,拉伸量应取较小值。

管制班组搭配协调性评价体系建立的研究

空中交通管制员在执行空中交通管制工作的时候必须按班组化的模式运行,班组搭配的协调性和合理性很大程度上影响着管制员的个人执业能力的发挥,从而以班组的规模效应影响着飞行安全和管制服务质量。建立一个合理的班组搭配协调性评价体系对于管制单位和行政管理人员来说既是提高单位人性化建设的重要过程,也是保障管制工作运行安全稳定的重要手段。

Numerical study on cavitation in a globe control valve with different numbers of anti-cavitation trims

Cavitation is a destructive phenomenon in control valves.In order to delay cavitation,a multi-series of perforated cylindrical plates,called trims,are used.Previously,the effects of orifice diameter and different types of trims have been investigated.In this study,by numerical analysis,a globe control valve was investigated by employing four different cases(without trim,with one trim,with two and three trims)and the impact of the number of these trims on the intensity,formation region and the initiation point of cavitation was analyzed.It was found that the addition of one stage or two stages of trims reduces the intensity and delays the onset of cavitation,relative to the valve without trim.However,no significant differences in terms of intensity and initiation point of cavitation were observed in the cases where two or three trims were used.Therefore,due to the high cost of producing the trims,and the severe drop in flow coefficient,it is not economically and technically justified to increase the number of trims to more than three.

Characteristic of Drop Coalescence Resting on Liquid-Liquid Interface

The trajectory model of dispersed phase drops and the model of basic flow for drop motion between two inclined parallel plates are derived with the optimized calculation. The analytical results of direct numerical simulation indicate that the basic flow plays an important role in the drop coalescence on liquid-liquid interface. In the stratified two-phase flow field, the smaller droplets are difficult to drain the thin continuous film between the approaching droplets and bulk interfaces and eventually immerse into the trickling film to yield coalescence. They almost attain the velocity of their local surroundings. Moreover, the basic flow exerts a dominant influence on the motion of smaller droplet. The smaller droplets are easily entrained by the basic flow. On the contrary, the larger drop presents advantageous characteristics of coalescence due to its high velocity. The range of 0.3 mm < δR≤ 0.75 mm is the advantageous drop coalescence condition since the rapidly varied velocity and its first derivative theoretically cause the forces acting on a drop to become imbalanced. On the other hand, the thin layer of the continuous phase drained from the interval between the drops and trickling film should not be neglected in the calculation of shearing force since it is important for drop rotation. The drop rotation is an indispensable factor in coalescence.

Variation in the temperature field of rocks overlying a high-temperature cavity during underground coal gasification

High temperature affects rocks in a way that changes the physical and mechanical properties of them. The temperature field in rock overlying a high temperature zone has been estimated using experimental research on thermal conductivity of the overlying strata. Numerical analysis software was used to esti- mate rock thermal conductivity at different temperatures. These estimates were then used with COMSOL Multiphysics to perform a numerical analysis with the heat conduction model. The results show that rock thermal conductivity decreases as the temperature increases and that various lithologies show similar behavior. The thermal conductivity of each rock type differs from the others at a given temperature. Exact values for the temperature distribution in the overlying strata during the process of underground coal gasification are obtained from the numerical simulation. The temperature in the rock changes with the height and direction from the gasifier. Temperature gradients vary for different types of rock. This result provides an important reference for further study of the strength of overlying strata subject to the process of underground coal gasification.

Experimental and Numerical Analysis of Turbulent Flow Heat Transfer Enhancement in a Horizontal Circular Tube Using Mesh Inserts

The present work focuses on experimental and numerical investigations of the augmentation of turbulent flow heat transfer in a horizontal circular tube by means of mesh inserts with air as the working fluid. Sixteen types of mesh inserts with screen diameters of 22 mm, 18 mm, 14 mm and 10 mm for varying distance between the screens of 50 mm, 100 mm, 150 mm and 200 mm in the porosity range of 99.73 to 99.98 were considered for experimentation. The horizontal tube was subjected to constant and uniform heat flux. The Reynolds number varied from 7,000 to 14,000. The results are compared with the clear flow case when no porous material was used. Computational fluid dynamics （CFD） techniques were also employed to perform optimization analysis of the mesh inserts. The horizontal tube along with mesh inserts was modeled in Gambit 2.2.30 with fine meshing and analyzed using FLUENT 6.2.16. CFD analysis was performed initially for plain tube and the results are compared with experimental values for validation.

Variation of hydraulic gradient in nonlinear finite strain consolidation

In the research field of ground water, hydraulic gradient is studied for decades. In the consolidation field, hydraulic gradient is yet to be investigated as an important hydraulic variable. So, the variation of hydraulic gradient in nonlinear finite strain consolidation was focused on in this work. Based on lab tests, the nonlinear compressibility and nonlinear permeability of Ningbo soft clay were obtained. Then, a strongly nonlinear governing equation was derived and it was solved with the finite element method.Afterwards, the numerical analysis was performed and it was verified with the existing experiment for Hong Kong marine clay. It can be found that the variation of hydraulic gradient is closely related to the magnitude of external load and the depth in soils. It is interesting that the absolute value of hydraulic gradient(AVHG) increases rapidly first and then decreases gradually after reaching the maximum at different depths of soils. Furthermore, the changing curves of AVHG can be roughly divided into five phases. This five-phase model can be employed to study the migration of pore water during consolidation.

Numerical analysis on stability of surrounding rock mass around deep roadway

Numerical simulations of the deep roadway were carried out through application of the strain-softening constitutive model. Differences between the deep and shallow roadway of the rock bearing structure were analyzed. Influences of the supporting resistance on the rock bearing structure at the deep roadway were discussed. The results show that there is alternation of strong and weak strength-softening region in the surrounding rock of deep roadway. However, the increase in the supporting resistance cuts down the size of strength-softening region of surrounding rock, decreases its strength-softening degree, and im- proves the stress distribution condition of the surrounding rock mass. It is concluded that the supporting resistance can raise the self-supporting ability of surrounding rock through controlling its strength-softening so as to make the rock bearing structure of deep roadway stable.

Full-Scale Measurement and Numerical Analysis of Liquefied Petroleum Gas Water Heaters with Ventilation Factors in Balcony

This study carried out full-scale gas water heater combustion experiments and adopted FDS （fire dynamics simulator） to simulate three scenarios--different balcony environments when using water heater, such as airtight balcony, indoor door with openings and force ventilation to compare with full-scale combustion experiments. According to FDS simulation results, 02, CO and CO2 simulation concentration value correspond with full-scale experimental results. When the indoor O2 concentration was lower than 15%, which causes incomplete combustion, the CO concentration would rise rapidly and even reached above 1,500 ppm, causing death in short time. In addition, when the force ventilation model supplied the water heater with enough air to bum, the indoor CO concentration will keep low and harmless to humans. The study also adopted diverse variables, such as the opening area of window, outdoor wind speed and water heater types, to analyze deeply user＇s safety regarding gas water heater. In a result, while balcony area is larger than 14 mE, the volume of water heater is below 16 L （33.1 kW）, and the indoor window, connecting balcony with room, is closed, if the opening on the outdoor window of the balcony is larger than 0.2 mE, this can ensure the personal security of the indoor space.

Performance Analysis of a Woodchip Downdraft Gasifier： Numerical Prediction and Experimental Validation

The study deals with a multi-faceted theoretical approach, symbolic, analytical and numerical, based on the chemical equilibrium assumption, addressed at predicting the performance trends of downdrafi wood-gasification processes so to assess the optimal ranges of input parameters, in particular the equivalence ratios, suitable to achieving the highest cold gas efficiencies whilst keeping the more the possible tar-free the produced bio-syngas. The time-steady, zero-dimensional model has been developed within MATLAB （the computing language and interactive environment from Matrix Laboratory） and solved by enforcing the constraints posed by the equilibrium constants in relation to two reactions, gas-water shift and methanation. Particular care is devoted toward verifying the real attainment of the equilibrium condition, as attested by an actual presence of products from the equilibrium reactions together with a zero difference AE between the energy flows entering and exiting the system, an issue often overlooked. With respect to other similar theoretical approaches, the numerical model, assisted by the symbolic counterpart for better interpretation and intrinsic validation of results, shows a distinct advantage in predicting rather accurately the syngas composition for varying gasification temperatures, as attested by cross comparisons with experimental data directly taken on an instrumented, dedicated, small-scale downdraft gasifier operational at DIME/SCL （the Savona Combustion Laboratory of DIME, the Dept. of Mechanical, Energy, Management and Transportation Engineering of Genova University）. The behavior of cold gas efficiency clearly points out that, from an energy conversion point of view, the optimal gasification temperatures turn out comprised between 900 ℃ and 1,000 ℃： this range is indeed characterized by the highest concentrations in the energy-rich syngas components CO and H2. For higher temperatures, as induced by higher air-to-fuel ratios, the progressive oxidation of above components, together with increasing nitrogen levels, would decrease the bio-syngas heat values.

Study on optimization of underlying coal bed exploited depth for tunnel

Combined with highway construction, the analysis on the relationship betweentunnel construction and coal resource exploitation was processed, which was based onthe research of rational exploitation depth of coal.3D FEM numerical analysis for tunnelexcavation was carried out according to engineering geological features of coal measurestrata in the project area.Based on the analysis of displacement and stress of the surroundingrock in the tunnel after excavation, the characteristics for displacement andstress of the tunnel support structure were analyzed when the underlying coal bed wasexploited with sublevel and full caving method.In addition, combined with the related codeand standard, the economic and safe prohibiting exploited depth of the underlying coalbed was proposed, so that a scientific basis for tunnel construction of coal measure strataand reasonable exploitation of the mineral resources in complex geological conditions canbe offered.

Research on the Human Resource Management Mode based on Competency Model

In this paper, we conduct in-depth research on the human resource management mode based on competency model. Treatment of competency is defined based on the previous scholars, this paper defines enterprise top management competency as can change the performance is outstanding person in senior management positions in companies and generally do distinguish individual potential. Corporate culture has a strong and lasting soft binding, plays an important role in modem enterprise management. The numerical analysis supports the effectiveness and feasibility of the model. In the future, we will conduct more related work to optimize the current theory.

Optimization of cross angle based on the pumping dynamics model

The single cylinder and multi-cylinder pumping dynamics model of a swash plate piston pump were improved.Particular attention has been paid to the design influences of key parts of the valve plate such as relief groove,pre-compression/ expansion and fluid inertia effect of the unsteady flow.Some important parameters,such as the discharge area,discharge coefficient,fluid bulk modulus,were especially analyzed using numerical methods or by experiment-based estimation.Consequently,the mathematical results of pressure pulsation and flow ripple agree well with experimental results from the test-rig of the flow ripple.Therefore,the cross angle and the pre-compression angle of the valve plate was optimized,based on the pumping dynamics model.Considering both the flow ripple and the cylinder pressure of the pump,the cross angle is set to be 2.2° to 2.7° with a pre-compression angle of 1.7° to 2.2°,so the pumping dynamics character can obtain the best result.