钛合金膜板热模锻造工艺的模拟式设计

利用热力耦合有限元程序DEFORM3D,对中等尺寸TC4 ELI合金膜板(外径为Φ360mm)的热模锻造工艺进行模拟式设计,对比了两种锻造工艺。结果表明,采用7Mn15合金模具,在两种锻造工艺条件下,模具材料因变形热效应及边界摩擦引起温升而失效,但是设备最大载荷均不超过25×103kN。两种锻造工艺中局部加载锻造工艺可以解决坯料定位和脱模问题,工艺适应性较好,模拟分析结果得到了生产实验验证。     

Electronic structure of π-conjugated oligomers and polymers: a quantum–chemical approach to transport properties

Nearly 25 years after the discovery that an organic conjugated polymer can be “doped” (that is, in chemical terminology, oxidized or reduced) to metallic-like electrical conductivity, the field of π-conjugated oligomers and polymers has enjoyed a tremendous development, most remarkably underlined by the 2000 Nobel Prize in Chemistry awarded to Alan Heeger, Alan MacDiarmid, and Hideki Shirakawa. Since, in this specific class of polymers, small variations in chemical structure play an essential role and the properties of interest directly depend on the electronic structure, quantum–chemical approaches, that take the chemical nature fully into account, have provided a most valuable input to the field. The results have helped to forge a fundamental understanding of the electronic and optical properties of π-conjugated materials and in guiding the experimental efforts toward novel compounds with enhanced characteristics. It is our main purpose in this contribution to illustrate the impact of quantum–chemical methods, more specifically in relation to transport processes. We do not dwell at all on the theoretical methodologies that have been designed, but rather on the concepts. We first recall the basic electronic-structure aspects of π-conjugated systems, that make their chemistry and physics so rich and fascinating. We then discuss the key role of interchain interactions and their impact on transport.     

Experimental studies for verification of thermal effects in cutting

Investigations on metal-cutting machining processes that were conducted since the second half of the twentieth century have considerably contributed to disclosing the principles underlying the cutting process. Although numerous studies have been carried out on this subject, a generally valid model of the cutting process and the interactions in the separating processes does not exist yet. Such a model could guarantee the disclosure of the principles of thermodynamic interactions between the cutting process and the involved machine structure. This contribution is twofold and presents an experimental setup used to determine cutting forces and temperatures in orthogonal cutting processes. The results are then used as a reference for simulations made with the Discrete Element Method (DEM). The DEM is due to its meshless nature well suited to capture large deformations and rupture of material which is included very naturally. It is examined to which extent the measured results can be captured with the DEM model.     

Could the acid doping of polyaniline represent the charge transfer interaction?

It is proposed to describe the acid doping of the emeraldine base (EB) of polyaniline (PANI) as a donor-acceptor interaction, followed by a charge separation (charge transfer) inside the complex formed according to the scheme: D + H-Acc= (D→H-Acc) D⁺-H +Acc⁻, where D is the imine center of EB and H-Acc the acceptor possessing the mobile H atom. The hydrogen mediator supplied from the acceptor molecule is joined to the polymer chain in the second stage of transformation. The electrochemical system, PANI electrode/hydroquinone (4F-hydroquinone) solution, has been investigated as a model of this D-H-Acc interaction. It has been found that the redox reactions of both hydroquinone systems take place on PANI practically without overpotential and, probably, the two-electron charge transfer processes are realized in such systems. Reaction currents depend on PANI quantities deposited on the Pt electrode. On the PANI/electrolyte interface the stoichiometric complex is formed; it consists of nearly four units of aniline and one molecule of quinone (hydroquinone). There exists a great electronic exchange into this surface complex involving the acid centers of PANI as hydrogen mediators in the charge transfer on an organic acceptor. D-H-Acc interaction between EB and hydroquinone/quinone under the ‘wet’ electrochemical and ‘dry’ solid-state condition has been compared. We have concluded that the electron exchange between the EB chain and surface adsorbed molecules is the necessary condition for the doping occurring in both cases. The similarity has been revealed between the reactive center in the PANI-quinone/hydroquinone redox system and the donor-acceptor interaction in porphyrin-quinone photochemical reactions and other biological systems. It is proposed to involve the quinone and other acceptor molecules in the optical processes occurring with the π-electron system of conducting polymers.     

On the simulation of a corona discharge by the similarity theory methods

A general system of equations for a corona discharge has been derived and reduced to a dimensionless form using the methods of the similarity and dimension theory. Criteria and conditions for the similarity of the processes occurring during a corona discharge have been determined. Formulas for free space-charge density have been derived; the classical structure of the current-voltage characteristic for an arbitrary system of electrodes has been confirmed by different methods: using the theory of similarity, analyzing self-similar solutions, approximating the field distribution, and averaging the equation for the current density with respect to the volume of the interelectrode gap. It has been shown that the quadratic pattern of the current-voltage characteristics of the corona discharge results from the linear dependence of the electric field intensity and the linear threshold dependence of the density of free space carriers on the voltage.     

电磁分离设备参数对铝硅合金中富铁相杂质分离效果的影响

电磁场发生器是电磁分离的动力来源,分离器是金属熔体的载体,它们的参数直接影响到电磁分离的效果。文中以铝硅合金中的富铁相杂质颗粒为分离对象,利用流动试验研究了磁感应强度、分离通道截面形状和金属熔体回路尺寸对分离效率的影响。试验结果表明,增加磁感应强度、采用平板型分离通道、增大金属熔体回路面积可以改善电磁分离的效果。     

叔胺萃取分离精炼铂的新工艺

用三烷基胺（Ｎ２３５）萃取分离铂，考察了稀释剂、改质剂浓度、料液酸度对分配系数的影响，从复杂的工业料液中，用Ｎ２３５萃取、洗涤、反萃、再生及精炼铂的工艺技术。     

Rheological similarity of metals and alloys

A rheological model of metals and alloys with a minimized number of parameters has been developed which makes possible the describing of complex experimental σ-ε dependencies. A system of rheological similarity criteria has been obtained which helps to select materials and models for the physical simulation of plastic deformation processes and to ascertain the similarity between metals and alloys for their rheological grouping.     

Theoretical studies on one- and two-photon absorption properties of rubrene and its derivatives

One- and two-photon absorption properties of a very intriguing perpendicular π-electron system 5,6,11,12-tetraphenylnaphthacene (rubrene) and its derivatives have been discussed from the theoretical investigation view. Based on the correct geometries, the INDO/SDCI method was adopted to determine the one-photon absorption (OPA) and two-photon absorption (TPA) properties. The elongation of π-conjugation and the perpendicular phenyl groups on two-photon absorption cross section (δ_max) of rubrene are investigated in detail. The results show that the extension of π-conjugation plays an important role on the magnitude of δ_max. In addition, the perpendicular phenyl groups favor to enhance the δ_max of rubrene, which can be seen from the dominant charge transfer (CT) contributing to TPA obviously. This CT process is a symmetrical intramolecular CT process from the pendent phenyl groups to the main π-backbone. At the same time, the relationship between substituents attached to rubrene and two-photon absorption cross section is also systematically discussed.     

A study on dual laser beam separation technology of KDP crystal

KDP crystal is an important optic-electro material in various laser systems, at present, the greatest difficulty is the cutting of large-scale crystals. In this study, a dual laser beam separation technology (DLBS) for KDP crystal has been developed by skillfully combining femtosecond laser and continuous fiber laser for the first time. The principle of DLBS is expounded. The effects of laser separating parameters, including laser output power, scanning speed, focal position and focal length on separating accuracy and quality (flatness and surface roughness S_a of the separated sidewall) were investigated. The key parameters were determined and optimized for the separating of raw materials with the minimal flatness and the separating of the end product crystals with minimal S_a. The results show that a clean crystal surface and an average S_a of 2.6843 μm separated sidewall without any pollution, subsurface damage and limbic fragmentation could be achieved by DLBS. The separating speed of DLBS is at least 20 times faster than that of the conventional method. A numerical simulation to analyze the mechanism of DLBS separating KDP crystal was developed, which is in good agreement with the theoretical analysis and experimental results.     

Study on mechanics and key technologies of laser nondestructive mirror-separation for KDP crystal

KDP crystal is an important electro-optic material in various laser systems. At present, the greatest difficulty is the cutting and polishing of large-scale crystals. In this study, a laser nondestructive mirror-separation technology (LNMS) for KDP crystal has been developed for the first time by skillfully adopting femtosecond laser pretreating and fiber laser separating. The separating efficiency of LNMS is at least 200 times faster than that of traditional mechanical cutting, and a nondestructive mirror-separated crystal sidewall with surface roughness (S_a) of 4.7 nm (P−V) and 2.1 nm (RMS), flatness of 5.433 μm and an angular precision about 0.06° could be obtained using the LNMS method. The effects of laser separating parameters, including laser power, laser moving speed and internal stress release on separating accuracy and quality, were investigated and optimized; meanwhile its principle was expounded as well as its mechanism was discussed. The experimental and analyzed results show that the LNMS technology may also have a prospect in the analysis of residual stress distribution inside KDP crystal. A numerical simulation on the thermal stress in the LNMS separating process of KDP crystal was developed to analyze the separating mechanism, which is in good agreement with the theoretical analysis and experimental results.     

A study of the application of upper bound method to the CONFORM process

This paper is concerned with the calculation of the powers required in the steady-state CONFORM process. For this goal, similarity is applied to the CONFORM process for an equivalent side extrusion process, to which the upper bound method is used to derive the equation for calculating the powers. Even though the global flow characteristics between the real and the simplified processes are not similar, the calculated results for both processes show good agreement. Furthermore, FEM simulation is carried out using the DEFORM commercial program in order to verify the theoretical results.     

重载车辆主离合器分离环表面磨损失效机理的研究

表面非均匀磨损是重载车辆主离合器分离环常见的失效形式。首先用三维激光测量仪对表面非均匀磨损进行了定量测量,然后采用显微分析的手段, 结合对该离合器的服役工况分析,对失效的重载车辆主离合器分离环工作面的失效机理进行了分析研究。结果表明:分离环弹子槽表面的失效主要原因是冲击式磨粒磨损。在此基础上,提出了提高主离合器分离环使用寿命的建议措施。     

An experimental and theoretical study of adsorption of aromatic alcohols and amines on graphitized thermal carbon black

The Henry constants have been calculated for nonrigid molecules of benzyl alcohol, 1-phenylethanol, benzylamine, and 1-phenylethylamine on graphitized thermal carbon black (GTCB). It has been shown that remarkable changes in geometry for stable conformers in the adsorbed state depend on the height of the barrier to internal rotation around the labile bond and the presence of an intermolecular hydrogen bond. The parameters of atom-atom potential (AAP) characterizing the intermolecular hydrogen bond of the OH-group with π-electrons of GTCB with the assumption of direction have been determined. The experimental values of the Henry constant have been compared with the results of a molecular statistical calculation for the aromatic alcohols and amines being studied on GTCB.     

Physics of plasticity

This paper considers: three-dimensional crystallizing π-bonding of nucleons by electrons; the structure of the periodic table; the three-dimensional crystallizing π-bondings of atoms and crystal structure; the characteristic orbitals of bcc, fcc and hcp and plastic deformation; plastic deformation by twins; plastic deformation by dislocations; hardening mechanisms; the fatigue limit; slip bands; reorientations of atoms and rotation of grains by three-dimensional crystallizing π-bondings; three-dimensional crystallizing π-bondings and the fatigue limit; three-dimensional crystallizing π-bondings of atom and wear; and three-dimensional crystallizing π-bonding of atoms and creep.     

Process layout avoiding reverse drawing wrinkles in hydroforming of sheet metal

Sheet metal forming processes like the fluid form process or hydromechanical deep drawing have the potential for the manufacture of parts having high precision, large drawing ratio, and low costs especially for small and medium lot sizes. In deep drawing using a separating membrane between the liquid and the sheet the process layout for drawing of complex parts must avoid not only the typical failures of bottom fracture, first and second order wrinkles, but also an additional type of wrinkles which are maybe created at the beginning of the process. The development of these wrinkles is described using an analytical model, which was validated by experimental results. The model was used to develop the process layout for deep drawing of a complex sheet metal part.     

铜合金中氧化物夹杂的电磁分离

通过向Cu-10Sn合金中加入1%的Cu2O颗粒制备了含有SnxOy合金的材料,随后利用高频磁场的电磁分离技术成功将铜合金中的氧化物夹杂分离到分离器边缘。研究了分离器直径、磁感应强度、分离时间对分离效果的影响。试验结果表明,当分离器直径为12mm,磁感应强度为60mT,分离时间为60s时,氧化物夹杂的分离效果最好。     

MH-Ni电池中稀土贮氢合金微结构的XRD研究

提出了分离微晶和微应力两种引起X衍射线条宽化效应的最小二乘方法。用该方法分析研究了不同工艺制备的贮氢合金的微结构，对比研究了MH-Ni电池中的贮氢合金在活化前后和循环寿命实验前后微结构的变化。结果表明活化对负极材料微结构产生重大影响；循环寿命实验后贮氢合金微结构的变化与循环条件密切相关。     

管轴压精密成形过程中管坯脱模点的预测

管轴压精密成形过程中 ,存在着管坯脱离模具而由约束变形到自由变形的转变 ,因而明确管坯脱模点的位置 ,将对整个成形过程的研究具有重要意义。本文采用有限元数值模拟 ,对成形过程中管坯的脱模特性及其影响因素进行了研究 ,结果表明 :管轴压成形过程中管坯的脱模状况 ,受到变形几何参数和材料参数的共同作用 ,其中几何参数是影响管坯脱模点位置的决定因素 ,材料参数则对脱模时的成形力影响很大     

三维光塑性中的应变分量的分解

光塑性方法是研究三维变形问题的比较简单易行的物理模拟方法，通过光塑性切片技术，可以获得复杂变形过程的应变分布。本文给出了三维光塑性的两种切片实验方法，推导了一般三维光塑性中应变分量的求解公式，给出了实验数据处理的数值解析方法，并编制了计算程序，该程序可用于一般光塑性实验的数据处理。