Influence of deformation path on the forming effect in a multistep flexible rolling process

The flexible rolling process(FRP) is a novel three-dimensional(3 D) forming process that combines the multipoint and traditional rolling forming. The principle of FRP is based on thickness thinning, so the deformation path significantly impacts the forming effect. In this study, the multistep forming process with different deformation paths was introduced to improve the forming effect of FRP. For instance, with the convex surface part, three finite element models of multistep FRP(MSFRP) were established. The corresponding numerical simulations and forming experiments performed among different deformation paths showed the surface part with a longer effective forming region was obtained and the forming regions with more steps in MSFRP were smoother. Thus, the sheet-metal utilization rate was greatly improved. Moreover, the MSFRP can improve the longitudinal bending effect dramatically and thereby endowing the forming part with a better forming effect. Therefore, MSFRP is a prospective method for broad applications.

A Study on the Ore-forming Effect of Mantle-derived Fluid

Based on summarizing of the effect of mantle-derived fluid on the formation of ores, especially on gold ore, and with the latest investigations, such as the formation of ore from the action of shallow-deep fluid, the transportation effect of the thermal energy by mantle-derived fluid, this paper mainly aims at the effect of mantle-derived fluid on the generation of hydrocarbons. With the proof from geochemistry and fluid inclusion, it was suggested that the mantle-derived fluid not only supplied source materials for hydrocarbons, but also supplied essential energy and matter necessary for the generation of hydrocarbons. The mantle-derived fluid had a good effect, but at the same time it had an adverse effect under specific conditions, on the formation of reservoirs. This paper also discusses the future direction and significance of studying mantle-derived fluid.

Effect of temperature on vacuum hot bulge forming of BT20 titanium alloy cylindrical workpiece

Temperature is one of the key parameters for BT20 titanium alloy cylindrical workpiece manufactured by vacuum hot bulge forming. A two-dimensional nonlinear thermo-mechanical coupled FE model was established. Numerical simulation of vacuum hot bulge forming process of titanium alloy cylindrical workpiece was carried out using FE analysis software MSC Marc. The effects of temperature on vacuum hot bulge forming of BT20 titanium alloy cylindrical workpiece were analyzed by numerical simulation. The simulated results show that the Y-direction displacement and the equivalent plastic strain of the workpiece increase with increasing bulge temperature. The residual stress decreases with increasing bulge temperature. The optimal temperature range of BT20 titanium alloy during vacuum hot bulge forming is 750-850 ℃. The corresponding experiments were carried out. The simulated results agreed well with the experimental results.

Edge effects of metal plate in laser forming

To search for the new scanning plan that can reduce the bending angle variation and the bending curvatures of the bending edge, an explanation for the causes of the edge effects was given. Six new scanning strategies were proposed through the change of the scanning length of middle and two ends based on the above analyses. Numerical simulations were carried out to study the edge effects using the six new scanning strategies. The simulation results show that the new scanning strategies can improve effectively the quality of the forming parts.

Dynamics of Quantum State and Effective Hamiltonian with Vector Differential Form of Motion Method

Effective Hamiltonians in periodically driven systems have received widespread attention for realization of novel quantum phases, non-equilibrium phase transition, and Majorana mode. Recently, the study of effective Hamiltonian using various methods has gained great interest. We consider a vector differential equation of motion to derive the effective Hamiltonian for any periodically driven two-level system, and the dynamics of the spin vector are an evolution under the Bloch sphere. Here, we investigate the properties of this equation and show that a sudden change of the effective Hamiltonian is expected. Furthermore, we present several exact relations, whose expressions are independent of the different starting points. Moreover, we deduce the effective Hamiltonian from the high-frequency limit, which approximately equals the results in previous studies. Our results show that the vector differential equation of motion is not affected by a convergence problem, and thus, can be used to numerically investigate the effective models in any periodic modulating system. Finally, we anticipate that the proposed method can be applied to experimental platforms that require time-periodic modulation, such as ultracold atoms and optical lattices.

Effect of Deformation Condition on Axial Compressive Precision Forming Process of Tube with Curling Die

The effect of the deformation condition on the axial compressive precision forming process of tube with curling die was investigated by using a rigid-plastic FEM. The results show that the forming accuracy depends mainly on geometric condition rp/d0, little on tube material properties and friction condition; the relative gap △/2rp of double-walled tubes obtained decreases with Increasing rp/d0, and there is a parameter k for a given to/do or rp/t0, when rp/d0 >k, △/2rp< 1, otherwise △/2rp>1.

Non-Synchronous Deformation Effect of Particle in Sheet Metal Forming Process

A new concept referred to the non-synchronous deformation effect of particle in sheet metal forming is proposed. The results of finite element analysis show that the flow resistance of sheet metal can be effectively reduced and thus the forming property can be greatly improved if the moving and deformation state of the neighboring elements with equal perpendicular distance to the entrance contour of die is non-synchronous. Experiment tests are presented and the results agree well with FEA simulation. In addition, the mechanism of the non-synchronous effect is analyzed in detail.

不同冷却方式锈蚀冷弯薄壁型钢材高温后力学性能

为研究冷弯薄壁型钢材料在高温和锈蚀耦合作用下力学性能变化规律,通过中性盐雾锈蚀、高温煅烧、冷却和拉伸试验,对180个经历0~60 d人工加速锈蚀和20~800℃高温煅烧后1.5 mm厚S280GD+Z型冷轧薄钢板在自然冷却和浸水冷却方式下的力学性能进行了试验研究。结果表明:在锈蚀和高温耦合作用下,钢材表面特征和破坏模式受冷却方式影响较大;锈蚀率小于6%时,锈蚀对S280GD+Z钢材力学性能影响较小;受火温度低于600℃时,受火温度及冷却方式对S280GD+Z钢材屈服强度、极限强度影响不显著;在锈蚀和高温耦合作用下,受火温度大于600℃后,钢材强度退化幅度变大并且高温在对钢材强度影响中占主导地位;冷却方式对钢材伸长率影响较大,自然冷却条件下,伸长率随受火温度呈先增加后减小趋势,浸水冷却条件下,伸长率随受火温度整体呈降低趋势。建立了锈蚀与高温耦合作用下,S280GD+Z钢材力学参数与锈蚀率、受火温度之间定量关系的数学模型,基于简化的二次塑流模型建立了锈蚀与高温耦合作用下S280GD+Z钢材本构模型。

Velocity Form Calculations of Generalized Oscillator Strengths for 3s→ (3p, 4p, 5p, 6p) Dipole Transitions of Atomic Sodium in Debye Plasma

In this paper, the generalized oscillator strengths (GOSs) of excitations of atomic sodium from ground state to 2p63s0 (3p, 4p, 5p, 6p) states, immersed in Debye plasma, were calculated by using wavefunctions which were obtained numerically from the restricted Hartree-Fock (RHF) equation. This RHF equation employs the local density approach for exchange interactions including plasma Debye screening. Theoretical RHF and random phase approximation with exchange (RPAE) velocity calculations have shown that the GOSs for excitations to 3 s0(3 p,4 p,5 p,6 p)depend on the plasma Debye screening effects, as shown by the reduction in the GOS amplitude with decreasing Debye length λD. The agreement between the present RPAE V results for the transitions 3 s→3 s0(3 p,4 p,5 p)and the length calculations of Martínez-Flores was satisfactory. Correlation effects were found quite to be significant in the vicinity of the maxima of the GOS of the 3 s→3 s0(4 p,5 p,6 p)excitations by using the RPAE V approach. We note the poor influence of many electron correlations on the GOS of (3 s→3 p)transition with the same principal quantum number. Finally, we comment that the RPAE V calculations are useful in investigating electron correlation effects on the transition GOS of atomic sodium planted in Debye plasma. The present velocity results also reveal that the 3 s→3 s0(5p, 6p)transition GOSs tend to be delocalized due to more significant screening effects at Debye lengths λD=20and 30 a.u. for excited subshells 5p and 6p, respectively. We report here novel results of GOS for 3 s→3 s06ptransition obtained from different Debye lengths.

超声振动塑性机理及本构建模研究进展

超声振动辅助成形技术是一项能场与物理场交叉的新兴绿色成形技术,因其可显著提高材料成形质量、减少材料成形缺陷,被广泛应用于材料加工领域。目前研究普遍认为,致使材料流动应力下降的体积效应与降低界面摩擦的表面效应是声塑性效应的主要作用机制。概述了超声振动辅助拉拔、拉深、渐进成形等先进成形工艺的原理,总结了3种典型超声塑性成形工艺的特点和研究进展。在此基础上,综述了超声振动辅助塑性机理下的应力叠加效应、声软化效应、残余效应以及动态冲击效应等体积塑性机制以及矢量效应与局部热效应的表面塑性机制,并分别对超声振动辅助体积塑性机制与表面塑性机制的研究进展进行了总结。其次,重点从体积效应和表面效应2个方面综述了超声振动辅助塑性成形本构模型,并从唯象模型和物理模型两方面总结了体积效应下本构模型的研究现状,同时总结了表面效应下摩擦模型的研究进展。最后归纳了超声振动辅助成形机理应用中存在的问题并对发展方向进行了展望。

槲皮素的生药资源、药理作用及主要剂型研究进展

槲皮素在植物界分布广泛,在洋葱、莲子、绿茶等食物和五味子、鱼腥草、槐花等中草药中均有较高含量。因槲皮素具有抗氧化、抗炎、抗菌、抗病毒、抗肿瘤、免疫调节和神经保护等多种生物学活性,对动脉粥样硬化、细菌感染、病毒感染、肿瘤、神经系统性疾病的治疗具有十分重要的意义。由于槲皮素具有溶解度低、水溶性差、生物利用度低等特性,限制了其临床应用。药物制剂新技术与新剂型有望攻克槲皮素的应用限制。笔者对槲皮素的生药资源、药理作用和主要剂型研究进展进行了综述。

Recent progress in fluorinated electrolytes for improving the performance of Li–S batteries

Lithium–sulfur(Li–S) batteries represent a "beyond Li-ion" technology with low cost and high theoretical energy density and should fulfill the ever-growing requirements of electric vehicles and stationary energy storage systems. However, the sulfur-based conversion reaction in conventional liquid electrolytes results in issues like the so-called shuttle effect of polysulfides and lithium dendrite growth, which deteriorate the electrochemical performance and safety of Li–S batteries. Optimization of conventional organic solvents(including ether and carbonate) by fluorination to form fluorinated electrolytes is a promising strategy for the practical application of Li–S batteries. The fluorinated electrolytes, owing to the high electronegativity of fluorine, possesses attractive physicochemical properties, including low melting point,high flash point, and low solubility of lithium polysulfide, and can form a compact and stable solid electrolyte interphase(SEI) with the lithium metal anode. Herein, we review recent advancements in the development of fluorinated electrolytes for use in Li–S batteries. The effect of solvent molecular structure on the performance of Li–S batteries and the formation mechanism of SEI on the cathode and anode sides are analyzed and discussed in detail. The remaining challenges and future perspectives of fluorinated electrolytes for Li–S batteries are also presented.

Using Focus-on-Form Instruction in the Second Language classroom

As applied teaching,it refers to focus-on-form instruction and focus-on-meaning instruction which have been used in the second language classroom.By analyzing what the effectiveness of focus-on-form instruction is,what the disadvantages of focus-on-meaning instruction are? Therefore,it makes the conclusion:focus-on-form instruction is better than focus-onmeaning instruction within the second language classroom.

复杂微型构件特种能场辅助微成形研究进展

随着复杂微型构件特征尺寸的不断减小,尺度范围不断扩大,材料种类日益增多,单纯依靠模具施加载荷的塑性微成形技术受到越来越多的挑战,成为制约微型构件实际应用的关键技术瓶颈。特种能场微成形技术利用超声场、电场和电磁场等能场与材料相互作用产生的特殊物理效应进行微加工,可以明显改善材料的塑性流动,降低微成形载荷,从而显著提高微型构件成形质量。本文综述了超声场、电场和电磁场等特种能场作用下塑性微成形的研究进展。首先探讨了特种能场作用下材料力学性能响应机制及微成形尺度极限,其次介绍了特种能场作用下微成形过程中材料微观组织结构演化与缺陷形成机理,最后总结了特种能场辅助微成形的关键工艺参数及其对成形质量的影响规律,强调了通过优化工艺参数实现高精度成形的重要性,为复杂微型构件的低成本、高效制造提供了新的技术路径。

政策扩散的效果评估:政策再创新及演化过程——基于地方政务服务改革探索中的多模式分析

扩散研究中经典的S型曲线,在解释中国的政策扩散过程时存在一定的局限性。基于“形式-内核”的二维分析框架,扩散结果可以初步类型化为完全扩散、扩散失败、象征性扩散与再创新性扩散。地方政务服务改革探索中存在多种模式创新,案例追踪研究发现:由于公共政策本身所具有的特性,政策扩散同技术扩散之间具有根本性的差别。一方面,公共政策失败可能导致扩散统计结果出现累计值下降的情况,这就削弱了S型曲线对扩散效果解释的精准性;另一方面,政策本身会根据地方发展差异进行本土化调适。中国地区间发展差异较大使得纯粹意义上的完全扩散和扩散失败,连同象征性扩散都有在成本约束下演化为再创新性扩散的倾向。研究在一定程度上丰富了对地方政府政策再创新行为逻辑的解释。应当明确,未来的政策扩散研究,特别是扩散持续性与稳定性的研究,应当跳出对政策价值的前提预设,对扩散过程中的政策本土化和再创新予以肯定和鼓励。

Teaching Form Reform of "Prevention and Control of Poultry and Poultry Diseases" Course in Higher Vocational Colleges

[ Objective] To meet the needs of ＂Prevention and Control of Poultry and Poultry Diseases＂ course in higher vocational colleges in new period. [Method] In order to introduce theoretical knowledge, enhance practical ability and train quality, teaching content, teaching methods and practical teaching of the course were explored according to trends of academic development and personnel training. [ Result] The reform of teaching form improved the teaching effect, mobilized the learning enthusiasm and initiative of students, and enhanced their ability to solve practical prob- lems. [ Conclusion] The teaching form of ＂Prevention and Control of Poultry and Poultry Diseases＂ course has been successfully reformed.

Effect of Phosphatization on Element Concentration of Cobalt-Rich Ferromanganese Crusts

A detailed study on a small scale of the effect of phosphatization on the chemistry of marine cobalt-rich ferromanganese crusts supplies useful information for the evaluation and comprehensive utilization of crust mineral resources. Sub-samples from top to bottom of a 10-cm thick sample from the NW Pacific Magellan seamount were taken at 5 mm intervals. The concentration profiles of ore-forming and rare earth elements show that obvious differences exist between young unphosphatized crusts and old phosphatized crusts. In the old crusts Fe, Mn, Si, Al, Zn, Mg, Co, Ni and Cu elements are depleted and Ca, P, Sr, Ba and Pb elements are enriched. The order of depletion is Co > Ni > Mg > Al > Mn > Si> Cu > Zn > Fe, while the order of enrichment is P > Ca > Ba > Pb > Sr. The phosphate mineral controls the concentration variation of the ore-forming elements in crusts and causes loss of the main ore-forming elements such as Co and Ni. The phosphatization also affects the abundance of REEs in the crusts. REEs are more abundant and the content of Ce in old crusts is higher than that in young crusts, however, the pattern of REEs and their fractionation characteristics in new and old crusts are not fundamentally changed. A Y-positive anomaly in old crusts has no relationship to the phosphatization.

基于镇咳祛痰作用的“形”与药材品质关联的桔梗“辨状论质”研究

目的:通过桔梗宏观性状(长、宽、厚、质量)、微观形状(乳汁管面积)以及桔梗总皂苷和镇咳祛痰作用的关联分析,探究基于桔梗“形”的“辨状论质”实质。方法:本研究对桔梗“状”中的“形”、桔梗总皂苷和镇咳祛痰的药效结果进行定量测定,分别进行“状-量-效”和“状-效”关联分析,讨论“形”与桔梗品质的关系。结果:不同来源桔梗“形”的量化值、总皂苷含量和镇咳祛痰量化结果均有一定差异。“状-量-效”关联结果显示桔梗质量可体现药材品质,“状-效”关联结果显示宽度、厚度和乳汁管面积均与咳嗽次数呈显著相关,桔梗质量与酚红排泄量呈显著相关。结论:桔梗总皂苷可体现桔梗药材品质。“状-效”和“状-量-效”关联分析均可体现“辨状论质”的实质,其中“状-效”分析更明确、针对性更强。

药学教育实践教学形成性评价有效性探索

重视实践教学和应用型人才培养质量是高等药学教育的发展规律。有效、科学的形成性评价可为药学教育实践教学学习过程提供持续动态测评与反馈,为药学教育优质人才培养提供有力保障。文章总结提升药学教育实践教学形成性评价有效性的实践路径,为构建良好的形成性评价体系和保障育人质量提供参考和研究基础。