摘要：To solve the defects of bottom concave appearing in the extrusion experiments of complex hollow aluminium profiles,a 3D finite element model for simulating steady-state porthole die extrusion process was established based on HyperXtrude software using Arbitrary Lagrangian–Eulerian(ALE)*** velocity distribution on the cross-section of the extrudate at the die exit and pressure distribution at different heights in the welding chamber were quantitatively *** obtain an uniformity of metal flow velocity at the die exit,the porthole die structure was optimized by adding baffle *** optimization,maximum displacement in the Y direction at the bottom of profile decreases from 1.1 to 0.15 mm,and the concave defects are remarkably *** research method provides an effective guidance for improving extrusion defects and optimizing the metal flow of complex hollow aluminium profiles during porthole die extrusion.

摘要：Objective: The aim of this study was to reduce or eliminate the stressors to enhance nursing students' clinical learning experience through implementation of an iterative approach that developed a personalised response to student ***: A prospective cohort research design was applied to collect data from a sample of undergraduate nursing students across the four study *** iterative approach was employed to improve students' learning experience and the Stressors in Nursing Students Scale-Chinese Version (SINS-CN) was used to measure student *** problems encountered by students were identified,refined and the responding solutions were worked out and implemented among this group of students through their first year to fourth ***: The overall SINS-CN mean score (2.17-2.82) of students was declined to a moderate ***: Having implemented iterative approach to address factors that led to stressful environments encountered by the nursing students,the overall stress score and each sub-dimension score decreased ***,it is recommended that this approach could be adopted by other colleagues in the nursing arena around the world.

摘要：An improved design method of pervious concrete was proposed to lower the deviation between the designed and actual porosity and maintain both mechanical property and permeability of pervious concrete. The improved design method is mainly based on the optimal volume ratio of paste to aggregate(VRPA), which was determined by testing the average thickness of cement paste coating aggregate. The performances of pervious concrete designed by the traditional method and the improved one were compared. The results show that with the increase of designed porosity, the reduction of compressive strength and flexural strength of pervious concrete designed by the improved method is significantly smaller than those designed by the traditional one. The maximum deviation between the designed and actual porosity of the pervious concrete by the improved method is only 1.54%, which is far less than 8.7% obtained by the traditional one. Micro-structural analysis shows that the porous distribution of pervious concrete designed by improved method exhibits better uniformity.

摘要：A series of novel indole derivatives were designed and synthesized and their inhibitory activity against B-Raf and HepG2 cell were also described. Among them, compounds 7a and 7b exhibited excellent potency, which showed the potential for further research as lead compounds.

摘要：In the generalized continuum mechanics(GCM)theory framework,asymmetric wave equations encompass the characteristic scale parameters of the medium,accounting for microstructure *** study integrates two theoretical branches of the GCM,the modified couple stress theory(M-CST)and the one-parameter second-strain-gradient theory,to form a novel asymmetric wave equation in a unified *** modeling of the asymmetric wave equation in a unified framework accurately describes subsurface structures with vital implications for subsequent seismic wave inversion and imaging ***,employing finite-difference(FD)methods for numerical modeling may introduce numerical dispersion,adversely affecting the accuracy of numerical *** design of an optimal FD operator is crucial for enhancing the accuracy of numerical modeling and emphasizing the scale ***,this study devises a hybrid scheme called the dung beetle optimization(DBO)algorithm with a simulated annealing(SA)algorithm,denoted as the SA-based hybrid DBO(SDBO)*** FD operator optimization method under the SDBO algorithm was developed and applied to the numerical modeling of asymmetric wave equations in a unified *** the DBO and SA algorithms mitigates the risk of convergence to a local *** numerical dispersion outcomes underscore that the proposed SDBO algorithm yields FD operators with precision errors constrained to 0.5‱while encompassing a broader spectrum *** result confirms the efficacy of the SDBO ***,the numerical modeling results demonstrate that the new FD method based on the SDBO algorithm effectively suppresses numerical dispersion and enhances the accuracy of elastic wave numerical modeling,thereby accentuating scale *** result is significant for extracting wavefield perturbations induced by complex microstructures in the medium and the analysis of scale effects.

摘要：The bubble behavior is one of the key factors for the design and the process of aluminum reduction cell using inert anode.A see-through cell is constructed to investigate the bubble flow behavior and the electrolyte flow pattern induced by *** test results show that the electrolyte is driven by the bubble to move around the cathode,and also some vortices occur in local *** bubble generated at the anode bottom undergoes the processes of formation,growth,sliding,detachment and ***,the bubble generated at the middle of anode detaches rapidly from the anode surface and moves upward and collides with other bubbles,which results in coalescence or *** bubbles are released into the atmosphere at the liquid surface,while some other bubbles taken by the electrolyte flush to the height higher than the mean horizontal level of the liquid and then drop down and move horizontally and they are released *** bubbles are kept unbroken and are sliding on the electrolyte *** diameter of bubble generated at inert anode is smaller than that of bubble generated at graphite ***,the bubbles on inert anode are spherical,which was different from those in tubular or disk form on graphite anode.

摘要：Estimation of support pressure is extremely important to the support system design and the construction safety of *** present,there are many methods for the estimation of support pressure based on different rock mass classification systems,such as Q system,GSI system and RMR ***,various rock mass classification systems are based on different tunnel geologic conditions in various ***,each rock mass classification system has a certain *** China,the BQ-Inex(BQ system)has been widely used in the field of rock engineering ever since its ***,there is still no estimation method of support pressure with BQ-index as *** on the field test data from 54 tunnels in China,a new empirical method considering BQ-Inex,tunnel span and rock weight is proposed to estimate the support pressure using multiple nonlinear regression analysis *** then the significance and necessity of support pressure estimation method for the safety of tunnel construction in China is explained through the comparison and analysis with the existing internationally widely used support pressure estimation methods of RMR system,Q system and GSI ***,the empirical method of estimating the support pressure based on BQ-index was applied to designing the support system in the China’s high-speed railway tunnel—Zhengwan high-speed railway and the rationality of this method has been verified through the data of field test.

摘要：提出采用有限差分束传输法设计出微棱镜相位补偿的2位电光A/D转换器的波导结构参数。利用保角变换方法对转换器的电极参数进行分析与设计。最后,得到优化参数:带宽?f=3.71GHz,特征阻抗49.76?,半波电压Vπ=9.25V,归一化功率输出为56.86%,波导输出间隔为250μm,器件长度为30mm。

摘要：文章从以培养创新型人才为目标的创新型课程特征入手,研究了设计思维的三类教育应用模式,分别为:核心理念引领课程设计思路、思维模型促进课程重构、创新工具提供方法支撑。在此基础上,文章重点探讨了设计思维指导下的创新型课程设计体系,包括:设计理念层面,基于设计思维特征开展课程设计的五个原则——结合时代背景设计创新项目,以学习者的深度参与为中心,多样且开放的小组合作方式,可视化、汇聚式的创意分享模式,迭代化、非线性化的问题解决流程;模块重构层面,以创新项目为核心,围绕定义问题、汇聚灵感,构思方案、设计原型,迭代修订、输出制品,使用改进、演化发展等四阶段实施教学;工具支持层面,基于四阶段的创新工具可为教师的课程实施提供具体操作支架。

摘要：考虑辐射安全和经济性,对中国先进研究堆(CARR)的水平烫源孔道作了屏蔽设计优化研究。通过分步计算,克服了MCNP4C在计算粒子深穿透问题中的耗时、结果差的缺陷。再建立模型,将转门的屏蔽设计优化问题转化为屏蔽材料的组合优化问题。使用特征统计算法(CSA)结合ANISN程序,编写屏蔽设计优化程序。经过大量方案的筛选,很快找到了符合辐射安全、经济性和材料的机械特性的屏蔽设计优化方案optCH2;用MCNP4C程序计算了优化的方案,并与原方案做了比较。结果表明,optCH2方案的安全性能和经济性都比原方案提高很多。