牙嵌齿轮最佳锻坯设计与最小精锻成形力的上限解

牙嵌齿轮因其结构形状所致无法切削加工，需要热锻成形．在实验基础上，提出了最佳锻坯应满足的条件，并确定了最佳锻坯形状．用上限法建立了牙嵌齿轮镦粗成形的金属流动模式，求得最小成形力的上限解，论证了采用最佳形状的锻坯可显著降低牙嵌齿轮精锻成形的单位压力，使锻件成形良好．     

曲轴RR法限制成形的模拟及模具结构优化

对于非椭圆截面曲臂的大型曲轴，其模具结构设计对曲轴成形后的形状尺寸精度影响极大。本采用三维刚粘塑性软件TFORM3对12V240曲轴RR法限制成形工艺及模具结构进行了设计分析。提出了防止成形缺陷产生的新的模具结构方案，该方案通过改进模腔横截面形状设计和增加模具水平镦粗面的斜度来加强模具对毛坯塑性变形的约束，从而为曲轴RR法镦锻工艺及模具设计提供理论依据。     

RR法全纤维曲轴弯曲镦锻成形的数值模拟

针对12V280曲轴,对RR法加工全纤维曲轴的过程进行了塑性有限元数值模拟,获得了曲柄臂部分的应力、应变分布和成形载荷-行程曲线,分析了摩擦系数对曲轴弯曲镦锻的影响.结果表明,曲轴弯曲镦锻的塑性变形区域主要集中在曲轴臂部;水平镦粗力大于垂直弯曲力;改善接触摩擦条件有利于曲轴成形质量.     

35CrMo曲轴热成形材料模型的研究

本文通过对大型曲轴用钢３５ＣｒＭｏ的热力模拟试验和数据处理,探讨了曲轴弯曲镦锻的热成形机制,研究了变形温度,应变速率等参量对３５ＣｒＭｏ钢应力应变关系和再结晶特征的影响。建立了该类钢热成形的材料模型、给有限元数值模拟曲轴弯曲镦锻热成形过程提供了基本数据,也为大型曲轴热成形力能参数和温度制度的合理确定提供了科学依据。材料模型的确定,对于研究热成形实质,预报与控制工艺质量和产品质量乃至新工艺开发都有重     

复杂钩舌锻件近净成形的预锻形状优化设计

提出了基于闭式模锻的铁路钩舌锻件的近净成形工艺方案,针对近净成形中的预锻成形件设计这一关键技术进行了研究。通过对终锻成形阶段金属流动特点的分析,设计了预锻成形工艺。将多重响应面法与数值模拟相结合,以锻件填充完整、锻件变形均匀性最好以及材料的损伤最小为目标函数对预锻成形件的形状进行了多目标优化,并通过成形试验验证了优化设计的结果。测量与分析结果表明,本文方法可获得优化的预锻件形状,基于本文设计出的预锻件,可得到无成形缺陷且精度好的终锻成形件,实现了钩舌锻件的近净成形。     

铝合金管坯低熔点塑性介质挤胀成形力学特征

为了揭示管坯低熔点塑性介质挤胀成形力学特征,对铝合金管坯低熔点塑性介质挤胀成形工艺过程进行了研究.将低熔点塑性介质作为传力介质填加到管坯的内腔里,两个水平冲头在挤压管坯的同时挤压管坯内的塑性介质,使其在受挤压过程中自行封闭,自行产生高压,在管坯两端轴向挤压力的共同作用下,最终将管坯挤胀成形为空心构件.研究结果表明:低熔点塑性介质挤胀成形时管坯和塑性介质两种材料同时发生塑性变形,管坯的变形流动是塑性介质的内压和冲头轴向挤压共同作用的结果,采用该工艺可以成形各种异型截面的空心构件.     

镁合金上机匣等温精锻工艺的研究

上机匣是某型号直升机的关键零件,几何形状复杂,锻件尺寸大,性能指标要求高,成形难度很大。根据该件的上述特点,采用了等温锻造工艺,成形温度为３５０～３６０℃。并采用组合的模具结构和局部加载方法等,成功地锻制出上机匣锻件。锻件的力学性能,高、低倍组织和尺寸精度均符合要求。     

锻造成形过程中温度场的有限元分析

论述了刚塑性有限元分析方法的基本原理，建立了热力耦合分析模型，开发了热力耦合刚塑性有限元分析软件．通过将圆柱体镦粗过程的模拟结果与有关文献中的模拟结果的比较，说明了该分析方法和程序的可靠性．采用新开发的程序系统对45#钢热镦粗成形进行了模拟分析，得出了反映温场变化的温度分布图，揭示了成形过程中塑性变形和温度场之间的内在联系．     

辊压塑性精成形机的研制和开发

辊锻是一种应用很广泛的回转体零件成形方法，但目前它主用用于粗加工，很少用于精成形，另外，辊锻加工材料利用率较低。中国国家专利“辊压塑性精成形机”将辊锻与闭式模锻的优点结合起来，改进了现有辊锻机，使其能精成形，并且材料利用率也提高了很多。本文说明了根据“辊压塑性精成形机”专利的设计思想在设计实验样机时如何解决支承辊中心距调整、齿轮齿条正确啮合、框架模板位置调整及顶出机构设计等技术问题，此外，还说明了在设计辊压塑性精成形模具时应考虑的一些问题。     

轴对称件扭压成形的粘塑性有限元分析

运用体积微可压缩法的三维刚粘塑性有限元方法，对轴对称体的扭压成形变形规律进行了模拟分析，结果表明：与一般镦粗成形相比，扭压成形具有可促使变形均匀、增中变一等优点。     

关于具负系数的星象函数

<正> 记单位圆|Z|<1内形如的单叶解析函数类为T。Silverman曾时这类函数进行了研究。若feT且满足条件 Re{zf′(z)/f(z)}>a,o≤a<1,|Z|<1,则称feT(a)。定理对于T(a)中所有函数f(z),使得当|Z|a都成立的这种r的上确界r~T=1/2是与a无关的。     

Stakeholder-Beteiligung in der klinischen Forschung: eine ethische Analyse

Definition of the problem

Concepts of stakeholder engagement are well established in business ethics and medical ethics. However, current approaches tend to see it as an end in itself. Thereby, two important aspects are often neglected: first, the general normative presuppositions of stakeholder engagement; second, moral implications concerning different modes of communication.

Arguments

The present article argues that normative presuppositions of stakeholder engagement can be understood by reconstructing existing approaches. Here, three ethical theories are relevant: deontology, contractualism, and discourse ethics. Furthermore, stakeholder involvement is related to modes of communication that range from information to empowerment. Drawing upon the example of clinical research, we argue that these modes have different normative weight in relation to the respective stakeholder’s form of affectedness.

Conclusion

We show why it is important for bioethics to reflect on the particular relation of affectedness and modes of participation, and how this can be realized in practice.

     

BS^x分子（离子）基态的结构与势能函数

应用B3LYP,B3P86方法以及6-311g,6-311g（d,p）,6-311＋＋g（df）,6-311＋＋g（3df）,aug-cc-pvdz,aug-cc-pvtz,D95（d）多种基组,对BS分子,BS＋及BS-离子基态进行几何优化和单点能扫描计算.用最小二乘法,拟合得到BSX（X=-1,0,＋1）分子（离子）基态的Murrell-Sorbie势能函数.由于BS分子计算结果与实验值符合得很好,首次给出了BSX（X=-1,0,＋1）分子（离子）的势能函数,为BSX（X=-1,0,＋1）分子（离子）的反应动力学提供了理论依据.     

气相中二氧化铬与乙烯反应机理的理论研究

用密度泛函B3LYP／6—311＋＋G（3df,3pd）//6—311G（2d,p）法研究了CrO2＋（2A1／^4A″）＋C2H4生成P1[Cr（OCH2）^＋（^2A″／^4A″）＋CH2O]和P2[CrO^＋（^2∑g/^4∑g）＋C2H2O]的气相反应,重点对影响反应机理和反应速率的势能面交叉现象进行了讨论,并运用Hammond假设和Yoshizawa等的内禀反应坐标单点垂直激发计算的方法大致确定了势能面交叉点（crossing point（CP））或势能面交叉缝（crossjng seam）的位置。研究结果表明,CrO2^＋活化乙烯C-C键是一个[2＋2]类型反应,整个反应经历了重排过程。     

Stability, detonation properties and pyrolysis mechanisms of polynitrotriprismanes C6H6-n（NO2）n （n=1-6）

To further test whether polynitriprismanes are capable of being potential high energy density materials (HEDMs), extensive theoretical calculations were carried out to investigate on a series of polynitrotriprismanes (PNNPs): C₆H_6−n (NO₂) _n (n=1−6). Heats of formation (HOFs), strain energies (SE), and disproportionation energy (DE) were obtained using B3LYP/6-311+G(2df, 2p)//B3LYP/6-31G* method by designing different isodesmic reactions, respectively. Detonation properties of PNNPs were obtained by the well-known KAMLET-JACOBS equations, using the predicted densities (ρ) obtained by Monte Carlo method and HOFs. It is found that they increase as the number of nitro groups n varies from 1 to 6, and PNNPs with n≥4 have excellent detonation properties. The relative stability and the pyrolysis mechanism of PNNPs were evaluated by the calculated bond dissociation energy (BDE). The comparison of BDE suggests that rupturing the C-C bond is the trigger for thermolysis of PNNPs. The computed BDE for cleavage of C-C bond (88.5 kJ/mol) further demonstrates that only the hexa-nitrotriprismane can be considered to be the target of HEDMs.     

Reactivity of Tourmaline by Quantum Chemical Calculations

ZnAb initio calculations on reactivity of tourmaline were performed using both Gaussian and density function theory discrete variation method （DFT-DVM）. The HF, B3LYP methods and basis sets STO-3G（3d,3p）,6-31G（3d,3p） and 6-311＋＋G（3df,3pd） were used in the calculations. The experimental results show energy value obtained from B3LYP and 6-31＋＋1G（3df,3pd） basis sets is more accurate than those from other methods. The highest occupied molecular orbital （HOMO） of the tourmaline cluster mainly consists of O atom of hydroxyl group with relative higher energy level, suggesting that chemical bond between those of electron acceptor and this site may readily form, indicating the higher reactivity of hydroxyl group. The lowest unoccupied molecular orbital （LUMO） of the tourmaline cluster are dominantly composed of Si, O of tetrahedron and Na with relative lower energy level, suggesting that these atoms may tend to form chemical bond with those of electron donor. The results also prove that the O atoms of the tourmaline cluster have stronger reactivity than other atoms.     

Velocity Field and Variation of Wall Thickness During Tube Dieless Upsetting

Theoretical analyses show that the variation of wall thickness is in direct proportion to outer-diameter, inter-diameter, and,（1 Rs平方根）Rs(Rs is sectional increase ratio of tube), the theoretical calculated results of wall thickness during tube dieless upsetting are very approximate to the experimental one. As the width of deformation field increases, both the variation of wall thickness and the derivative of wall thickness variation to width of deformation field (tf/to） reduce.     

不同稻草投加量对SRB去除硫酸盐的影响

目的以稻草作为碳源,研究不同相对投加量对硫酸盐还原菌（SRB）处理硫酸盐废水的影响,确定去除硫酸盐的最佳稻草相对投加量．方法利用静态试验,在6组反应器（R1-R6）中接种富含SRB活性污泥,pH在7-7．5,T=35℃,w（SO4^2-）=2000mg／L的厌氧环境下,分别投加1g,5g,10g,15g,20g,25g稻草,测定体系中SO4^2-、COD、VFA、pH等指标变化情况．结果6组反应器硫酸盐去除率分别为7．72％,67．52％,100％,100％,100％,VFA去除率分别为89．45％,70．48％,32．12％,20．67％,19．58％,15．79％．R1、R2中COD去除率均达到100％,R3～R6中COD质量浓度不断增加．反应体系中C、N、P质量比为m（C）：m（N）：m（PR1）=7：6．5：1,m（C）：m（N）：m（PR2）=100：5：1,m（C）：rn（N）：m（PR3-R6）远大于100：5：1,碳硫质量浓度比为w（COD）／w（SO4^2-）R1=0．028,w（COD）／w（SO4^2-）R2=0．417,w（COD）／w（SO4^2-）R3-R6〉3．体系中pH均呈现出先降低后上升的趋势．结论稻草相对投加量为5g时,硫酸盐的处理效果最佳,此相对投加量下w（COD）／w（SO4^2-）值接近SRB完全降解硫酸盐的理论值0．617,SO4^2-、COD与VFA去除率较高,1g稻草去除0．132g硫酸盐,反应体系中C、N、P质量比与pH均达到SRB适宜生长的环境条件．     

高强钢板组合螺栓抗拉性能有限元分析

高强钢板钻孔攻丝后替代螺母,与高强螺杆组合成一种新的单边螺栓连接副,可用于钢管柱框架节点.为研究钢板组合螺栓抗拉承载力和破坏机理,在本组试验研究的基础上对4类钢板组合螺栓共64个试件进行单调拉伸数值模拟,以板厚和螺杆直径为研究变量,包括Q345B、45号钢、Q460C和Q690D四种钢材和10.9级M16、M20、M24、M27和M30五种规格高强螺栓.结果表明:Q345B、Q460C和Q690D均可作为45号钢的替代材料;钢板组合螺栓在锚固可靠的条件下,可按螺杆螺纹极限抗拉荷载的70%作为其抗拉设计值;钢板较薄时,发生钢板螺纹滑牙破坏,螺栓拔出,螺杆最大应力位于锚固区,钢板向外凸起,凸起量大于支点间距的1/200;钢板较厚时,发生螺杆拉断破坏,螺杆最大应力位于构造区,两种破坏模式中钢板的最大应力均位于钢板螺纹第一扣处.为保证钢板组合螺栓不发生钢板螺纹滑牙破坏,建议Q345B钢板厚度不宜低于1.15d;Q460C钢板厚度不宜低于1.10d;Q690D钢板厚度不宜低于0.95d,根据弹性力学和螺纹传力机理推导高强钢板组合螺栓抗拉承载力公式,公式计算结果与有限元结果吻合良好,研究成果可为钢板组合螺栓的设计提供参考.     

Moment tensor analysis of transversely isotropic shale based on the discrete element method

In this study,the moment tensor of transversely isotropic shale was analyzed using a discrete element method-acoustic emission model(DEM-AE model).Firstly,the failure modes of the shale obtained from the acoustic emission(AE) events and physical experiments were compared.Secondly,the relationships between AE events and seismic magnitudes,and AE events and the resulting cracks were analyzed.Finally,a moment tensor T-k chart describing the seismic source was introduced to demonstrate the differences in the transversely isotropic shale.The results showed that,for different anisotropy angles,a linear logarithmic relationship existed between the cumulative AE events and the seismic magnitude in the concentration area of the AE events.A normal distribution was observed for the number of AE events as the seismic magnitude changed from small to large.The moment tensor T-k chart indicated that the number and proportion of linear tension cracks in the shale were highest.When θ = 30°,the peak seismic magnitude was at a minimum.The average seismic magnitude in the concentration area of the AE events was also relatively small.Points close to the U=-1/3V line and the number of cracks included in a single AE event were at a minimum,and the corresponding peak stress also reached its lowest level.In contrast,when θ=90°,all related parameters were contrary to the above θ = 30° case.The DEM-AE model and the moment tensor T-k chart are suitable for analyzing the distribution of shale cracks appearing during the loading process.This study can provide constructive references for future research on the fracturing treatment of shale.