Validity assessment of ductile fracture criteria in cold forming

This paper describes the assessment of various empirical and semiempirical ductile fracture criteria to determine their ability to predict the occurrence of fracture in metalforming processes. The criteria assessed are reformulated such that each is expressed in terms of mostly nondimensional material-dependent quantities and constants. The constants in each criterion are determined using data from published experimental results on cold upsetting of aluminum and steel specimens. The limit strain or the forming limit corresponding to each criterion is then determined and compared with the experimental data. There is clearly good agreement between theory and experiment for several criteria, but the predictions of other criteria fall far from experimental results.     

Online adaption of milling parameters for a stable and productive process

On the way to fully autonomous machine tools it is essential to independently select suitable process parameters and adapt them on-the-fly to the appropriate process conditions in a self-controlled manner. Such systems require complex physical process models and are usually limited to feed and spindle speed adaption during the milling process. This paper introduces a new approach enabling machines during the milling process to learn which parameters lead to a stable process with maximum productivity and to adjust them autonomously. It is shown that this approach enables the machine tool to independently find stable process parameters with maximum productivity.     

Structure of white cast iron and its conformity with the Charpy rule

Conclusions It was shown that it is possible to obtain a structure of white cast iron conforming with Charpy's rule by means of hot working.Ural Scientific-Research Institute of Ferrous Metals. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 5, p. 48, May, 1975.     

Alternating current corrosion of cathodically protected pipelines: Discussion of the involved processes and their consequences on the critical interference values

Based on laboratory studies and model concepts, a profound understanding of the involved processes in ac corrosion and the required limits has been obtained in the last years. But there was no information whether these thresholds can be effectively applied to pipelines or whether operational constraints make their implementation impossible. Therefore, an extensive field test was carried out. Thereby, the relevance of the laboratory tests for field application could be demonstrated and all threshold values were confirmed. Detailed analysis made it possible to explain the observed threshold values based on thermodynamic and kinetic considerations. The results summarized in the present work are the basis for the normative work defining the thresholds for the operation conditions of cathodically protected pipelines.     

Ternary rare-earth aluminum systems with copper: A review and a contribution to their assessment

Constitutional data of the R-Cu-Al systems, with R = rare earth, are summarized and discussed. Crystal structures of the phases formed in the binary boundary systems and in the ternary systems are assessed, and the phase equilibria observed in the reported ternary systems are reviewed with special attention given to the isothermal and polythermal sections of the phase diagrams. Some regularities observed in the trends of the constitutional properties of the ternary R-Cu-Al alloys are briefly described.     

Ternary rare earth germanium systems with Cu and Ag—A review and a contribution to their assessment

Constitutional data of the R-(Ag, Cu)-Ge systems, with R=rare earth, are summarized and discussed. Crystal structures of the phases formed in the binary boundary systems and in the ternary systems are assessed, and the phase equilibria observed in the reported ternary systems are reviewed with special attention to the isothermal sections (generally at 400 or 600 °C) of the phase diagrams. Some regularities observed in the trends of the constitutional properties of the ternary R-(Ag, Cu)-Ge alloys are briefly described.     

Ternary rare earth germanium systems with Cu and Ag—A review and a contribution to their assessment

Constitutional data of the R-(Ag, Cu)-Ge systems, with R=rare earth, are summarized and discussed. Crystal structures of the phases formed in the binary boundary systems and in the ternary systems are assessed, and the phase equilibria observed in the reported ternary systems are reviewed with special attention to the isothermal sections (generally at 400 or 600 °C) of the phase diagrams. Some regularities observed in the trends of the constitutional properties of the ternary R-(Ag, Cu)-Ge alloys are briefly described.     

Debris and consequences in micro electric discharge machining of micro-holes

The tip shape of a blind micro-hole produced using micro electrical discharge machining varies with respect to the process parameters used during machining. The usual tip shape is a blunt geometry within the common range of applications, however, under specific machining conditions and machining depths, the tip shape changes drastically to an inverted concaved shape. The origin of such tip deformation in micro electric discharge machining of blind micro-holes was investigated. It was observed that debris particles produced during machining accumulated at the tip, formed a hill and functioned as a tool electrode especially when using fine machining conditions. The phenomena is elaborated experimentally with the affecting parameters to describe the wear mechanism. Open gap voltage, pulse energy and tool rotation speed are examined as varying parameters during the experiments.     

注射用伏立康唑药物利用评价标准的建立和应用

目的: 建立注射用伏立康唑药物利用评价（DUE）标准,为临床合理用药提供参考。方法: 以注射用伏立康唑药品说明书为基础,参照相关规范、指南和文献,建立注射用伏立康唑DUE标准;并以此为依据,采用回顾性研究方法,对我院2017年7月至2018年7月121例使用注射用伏立康唑住院患者的用药指征、用药过程、用药结果、管理指标等进行综合评价分析。结果: 用药指征符合标准百分率为66.9%（目标值为90%）;给药途径、溶媒选择、配制方法符合标准百分率为100%（目标值为100%）;给药剂量和疗程符合标准百分率为31.4%和81.0%（目标值为95%）;微生物送检率为43.8%（目标值为80%）;用药有效率为50.4%（目标值为80%）;使用权限管理符合标准百分率73.6%（目标值100%）。结论: 本研究所建立的DUE标准可用于评价和规范注射用伏立康唑的临床合理使用。     

Modeling microbial sulfate reduction and the consequences for corrosion of copper canisters

The copper sulfide model (CSM) is a one-dimensional reactive transport code for predicting the evolution of the corrosion behavior of a copper canister in a deep geological repository. Here, the CSM has been extended to simulate the microbial reduction of sulfate in the repository and the consequences for corrosion of the canister. Organotrophic and chemotrophic sulfate reduction are represented by Monod kinetics, along with the dissolution of solid organic matter and gypsum as sources of nutrient and an electron acceptor, respectively. Siderite dissolution in the buffer and tunnel backfill materials acts as a source of Fe(II), which can then precipitate the microbially produced sulfide as mackinawite. Results are presented for a simulation representing the expected evolution of the corrosion behavior and repository environment and for a series of sensitivity analyses designed to identify the most important processes in the overall reaction scheme.     

Stability of n-type doped conducting polymers and consequences for polymeric microelectronic devices

Present polymeric microelectronic devices are typically unipolar devices, based on p-type semiconducting polymers. Bipolar devices stable under ambient conditions are desirable, but have not yet been reported due to a lack of stable n-type doped conducting polymers. Starting from the standard redox potentials of, especially, water and oxygen, stability requirements on electrode potentials of n-type doped conducting polymers are derived. The predictions are then compared with experimental data on stability of conducting polymers. A good agreement is obtained. An electrode potential of about 0 to + 0.5 V (SCE) is required for stable n-type doped polymers, similar to the requirement on the electrode potential for stable undoped p-type polymers. Consequences for bipolar devices are analysed. Huge overpotentials for the redox reaction with wet oxygen are required in order to realize thermodynamically stable bipolar devices from known doped p-type and n-type conducting polymers. Finally, possible solutions, accepting thermodynamic instability, are discussed.     

An evaluation of switching criteria for ferroelectrics under stress and electric field

The multi-axial responses of barium titanate (BaTiO₃) and hard lead zirconate titanate (PZT-4D) are measured for stress and electric field loadings, and are compared to the response of soft lead zirconate titanate (PZT-5H) taken from a previous study. First, poled ferroelectric specimens are subjected to an electric field at an angle to the original poling direction. Second, unpoled ferroelectric specimens are loaded by a uniaxial compressive stress and a parallel, proportional electric field. The switching surfaces of BaTiO₃ and PZT-4D are constructed from the experimental measurements, and compared with existing data for PZT-5H. The measured responses are then used to evaluate the accuracy of existing micromechanical and phenomenological models of ferroelectric switching.     

Generating mechanism and formation criteria of kinked surface in peripheral end milling

A kinked surface is commonly generated in a peripheral end milling process. In this paper, the generating mechanism of a kinked surface in end milling is systematically analyzed and revealed under the convolution framework through the establishment of a surface generation and form error model. It is found that the shape and kink positions of a form error profile can be determined by the three angular parameters: the axial and radial immersion angles and the flute spacing angle. From these angular parameters, four types of flute/work engagement conditions are defined to serve as the kink formation criteria with each type generating its own distinctive surface error profile in both down and up milling configurations. These form error profiles are characterized by either a kink-free form or by a single or a combination of three types of kink forms, which are defined based on changes in the flute/work engagement conditions and the resulting slope discontinuity in the force profile. Based on the kink formation criteria, kink charts scaled in normalized axial and radial depths of cut are devised to identify the types of kinked surface generated at any given depths of cut. An algebraic closed-form expression for the positions of kink points is also derived. The proposed kink formation criteria, the kink chart and the kink height prediction are validated through experiments and by comparison with data extracted from previously published results.     

儿科人血白蛋白药物利用评价标准的建立与应用

目的：为儿科合理应用人血白蛋白提供参考。方法：以人血白蛋白说明书为基础,参考儿科使用人血白蛋白的相关指南和文献资料,拟订药物利用评价标准初稿并列成专家咨询调查表,通过两轮的专家讨论形成定稿。应用该标准回顾性地对我院儿科2019年6月至2020年1月使用人血白蛋白的住院患儿病历进行评价。结果：本研究建立的标准包括用药指征、用药过程、用药结果3个一级指标及适应证、禁忌证、治疗过程监测、药物应用情况、疗效、不良反应6个二级指标。纳入本次评价的住院患儿病历共269份,其中新生儿占比最高（56.88%）。符合适应证229例,占85.13%;用药前检测血清白蛋白浓度有251例,占93.31%;用药后相关指标达标,症状改善明显的有226例,占84.01%。结论：我院所建立的儿科人血白蛋白药物利用评价标准具有较强的实用性,有利于发现临床用药中存在的问题或不足,促进临床合理用药。     

Electronic and structural consequences of n-doping: bithiazole oligomers and partially reduced bithiazolium cations

N-methylated-poly(diakyl-bithiazoles), NPABTs, can be reduced to give reasonably stable n-doped polymers. In order to understand the changes in the electronic structure and polymer conformations upon reductive doping of NPABTs, a series of oligomers of increasing length was studied by self-consistent field (AM1) and configuration interaction (ZINDO/S) calculations. Large red shifts in the optical transitions are predicted upon n-doping, along with significant planarization of chain segments. Full planarization was not realized for n-doped materials, however, as a variety of localized units were observed.     

安徽池州灌口锌多金属矿矿床成因及找矿标志

安徽池州灌口锌多金属矿属长江中下游成矿带之贵池—青阳铜、钼、金银、铅锌成矿亚带,具有明显的成矿系统.为在研究区进一步寻找更多的矿产资源,文章通过分析矿区地质特征,总结矿床成因,提出找矿标志,同时圈定找矿远景区,以期为今后研究区找矿提供支撑.