Anodic oxidation of iron during the purification of sulfate zinc solutions

The anodic oxidation of iron in zinc solutions is carried out using a two-chamber electrolyzer separated by an anionite membrane. The positive effect that copper ions in the solution have on the rate and completeness of the oxidation processes is shown. This method is effective for cleaning the solutions of zinc production and processing the industrial zinc-containing wastes.     

红透山矿充填系统现状及问题浅析

本文主要阐述了红透山矿业公司充填系统的现状,采用的充填方式,随采深不断增加而产生的充填倍线过小、管线过长、落差过大等问题,以及针对上述问题而提出的解决方案。     

应用进路式采矿工艺回收间柱方案研究

通过对间柱在充填体包围下的应力分析及充填体的破坏原理,论述对间柱回收的方案,并结合回收过程中可能出现的问题,提出解决思路、办法。     

Novel regio- and stereoselective O-6-desulfation of the glucosamine moiety of heparin with N-methylpyrrolidinone-water or N,N-dimethylformamide-water mixtures

The degree of completeness and selectivity of the solvolytic O-6-desulfation reactions of the glucosamine moiety adjacent to the 2-O-sulfoiduronic acid group of heparin was systematically studied. Using solutions of various ammonium salts of heparin (salts of tributylamine, quinoline and pyridine) in mixtures of 9:1 aprotic solvents and water (solvents of medium polarity, in order of decreasing polarity: Me2SO > Me2NCHO > Me2NAc > N-methylpyrrolidinone), the influence of different reaction conditions were studied. The ammonium salt of heparin with a strong base (e.g., tributylamine) in Me2SO showed almost no desulfation, while in Me2NCHO a relatively low degree of completeness of O-6-desulfation (30%) with moderate selectivity (15% [I-2(OS)]-desulfation) was observed. Weak bases like quinoline or pyridine in Me2SO-water resulted in nearly complete [A-6(OS)]-desulfation (95 and 94%, respectively) with low selectivity [I-2(OS)]-desulfation (49 and 35%, respectively). The heparin pyridinium salt in Me2NCHO-water showed both a relatively high degree of completeness and high selectivity (72% [A-6(OS)]- and 8% [I-2(OS)]-desulfation). The highest regioselectivity (i.e., a high degree of completeness accompanied by high selectivity) was achieved using an N-methylpyrrolidinone-water mixture (88% [A-6(OS)]-desulfation and 10% [I-2(OS)]-desulfation). A nearly complete O-6-desulfation (95%), accompanied by a lower selectivity (18% [I-2(OS)]-desulfation), was achieved when the reaction was carried out twice. Lower temperature improved selectivity (5% [I-2(OS)]-desulfation) but reduced the completeness of [A-6(OS)]-desulfation (72%). In comparison with the variety of O-6-desulfations reported to date, the novel reactions presented in this article led to remarkable increase in completeness and regioselectivity of the reactions that were investigated.     

高炉炼铁数据缺失处理研究初探

针对高炉炼铁过程中的数据缺失问题,提出以单维结合多维的系统化数据填补模式.总结并阐述数据缺失填补办法的发展现状以及优劣势比较.在此基础上,通过对河北某钢铁厂的实际高炉生产数据进行分类比较,并结合填补办法的优缺点,针对高炉炼铁数据提出一套以简单统计类办法、线性插值法、机器学习法等多种办法相结合的方案,以实现高炉数据的深度...     

Estimate of Landfill Settlements Due to Mechanical and Decompositional Processes

Approximate closed form solutions are developed for estimating the mechanical and decomposition settlement of landfills. The mechanical settlements are the immediate (primary) settlement and long term creep. The decomposition settlements are generated by mass loss and gas generation. Based on the approximate solution, the decomposition settlement can constitute a significant portion of the total settlement and can be in the same order as the mechanical settlements. Settlement remaining after landfill closure depends on the decomposition environment during filling. For an average decomposition environment, postoperation settlement can still be significant 20?years after completion of filling.     

基于博弈论的主客观组合权重TOPSIS采矿方法优选

针对当前采矿方法优选过程中,权重计算时主观权重信息丢失较多且占比过大的问题,将主客观权重相结合,计算出综合权重,并运用于采矿方法优选体系。首先,利用模糊扩展层次分析法（FEAHP）计算主观权重,最大程度地保存主观信息;然后,利用CRITIC客观赋权法计算客观权重,并运用博弈论原理将主客观权重相结合,得到综合权重;最后,结合逼近理想解的排序方法（TOPSIS）,建立基于博弈论的主客观组合权重TOPSIS采矿方法优选模型。将所建立的基于博弈论的主客观组合权重TOPSIS采矿方法优选模型运用于工程实例中,对姑山露天铁矿驻留矿体的采矿方法进行优选,计算出4种备选方案（上向进路胶结充填法、浅孔留矿嗣后充填法、上向水平分层充填法和下向水平分层充填法）的相对贴近度分别为0.4547、0.4441、0.5872和0.4072,得出上向水平分层充填法为最优方案。研究结果与矿山工程实例相符,证明基于博弈论组合的主客观权重值比以往单一的赋权法得到的权重值更加合理,建立的模型更科学。     

On the partial atomic volume of aluminum in solid solutions based on the 3d transition metals and copper

The composition dependence of the average atomic volume, as well as of the enthalpy of formation, was investigated for the aluminum-containing systems with the 3d transition metals and copper. The partial atomic volume of aluminum and the partial molar enthalpy of aluminum were determined for the transition metal-based solid solutions. Independent of the type of solid-solution structure, the (negative) partial molar enthalpy of aluminum increases and the partial atomic volume of aluminum decreases with increasing filling of the 3d band. The charge transfer and the bonding in solid solutions exhibiting close-packed structures (coordination number (CN)=12) is substantially higher than in solid solutions, based on the bcc structure (CN=8). The s electron of copper, though, reduces the charge transfer and the bonding in the fcc solid-solution Cu(Al) significantly.     

Button versus buttonless castings for removable partial denture frameworks

Casting removable partial dentures (RPDs) without completely filling the sprue channels and generating casting buttons would result in saving metal and making more defect-free castings. This investigation tested whether a complete and sound RPD casting can be obtained when a minimal amount of metal is used. A factorial experimental design, three spruing methods, two metal feeding directions, and two different weights of metal were used to cast 60 Kennedy class II, modification 1 RPDs. The metal used to cast each framework was either enough to result in a full button or in no button. Visual and radiographic examinations and counting of defects were made by two independent operators who were unaware of the spruing method, feeding direction, or amount of metal used to make the framework. The completeness of the casting and the presence of porosities were evaluated for clasps, major connectors, and meshworks. The use of minimal metal to cast RPDs was equally as successful as using enough for a full button, provided that the appropriate spruing arrangement and metal feeding direction were chosen. Indirect metal feeding for maxillary RPDs was successful with the proper spruing arrangement.     

The fine structure of X-ray absorption K-spectra of titanium in complex solid solutions of the TiC-TiN system

Summary The authors investigated the fine structure of absorption spectra of titanium in solid solutions of the TiC-TiN system. It is shown that the degree of filling of the 3d-band of the metal and the nature of its interaction with metalloid atoms remains practically unchanged.The authors would like to thank Corresponding Member of the Academy of Sciences of the UkrSSRG. V. Samsonov for providing the carbonitrides for the investigations and for his interest in the work.     

Capillary electrophoretic separation of 1 to 10 kbp sized dsDNA using poly(ethylene oxide) solutions in the presence of electroosmotic counterflow

DNA fragments of 1 to 10 kbp in length were separated by capillary electrophoresis (CE), using poly(ethylene oxide) (PEO) solutions in the presence of electroosmotic flow. The technique requires filling the capillary with the polymer solution by means of electroosmotic flow (EOF). Separation times of 6-7 min in PEO solutions ranging from 0.3 to 8 x 10(6) Mr at 375 V/cm were sufficient to separate the 11 components of the dsDNA ladder (0.5 to 10 kbp) by size. The migration behavior of the double-stranded (ds)DNA fragments, interpreted by "Ferguson plot analysis", in the system is indistinguishable from that previously reported for capillary zone electrophoresis (CZE) in a polyacrylamide solution without EOF. Potential advantages of conducting CZE using polymer solutions in the presence of EOF are: (i) Possibility of long migration times on short columns; (ii) possibility of introducing relatively viscous, high Mr polymer solutions into narrow capillaries; (iii) possibility of establishing polymer concentration gradients in capillaries; (iv) possibility of concentrating the starting zone by balancing electrophoretic migration and electroosmotic transport.     

Moving Least-Squares Differential Quadrature Method for Free Vibration of Antisymmetric Laminates

In this paper, the moving least-squares differential quadrature (MLSDQ) method is employed for free vibration of thick antisymmetric laminates based on the first-order shear deformation theory. The generalized displacements of the laminates are independently approximated with the centered moving least-squares (MLS) technique within each domain of influence. The MLS nodal shape functions and their partial derivatives are computed quickly through back-substitutions after only one LU decomposition. Subsequently, the weighting coefficients in the MLSDQ discretization are determined with the nodal partial derivatives of the MLS shape functions. The MLSDQ method combines the merits of both the differential quadrature and meshless methods which can be conveniently applied to complex domains and irregular discretizations without loss of implementation efficiency and numerical accuracy. The natural frequencies of the laminates with various edge conditions, ply angles, and shapes are calculated and compared with the existing solutions to study the numerical accuracy and stability of the MLSDQ method. Effects of support size, order of completeness of basis functions, and node irregularity on the numerical accuracy are investigated in detail.     

Translational Failure Analysis of Landfills

The scope of this paper is to develop a new approach to the two-part wedge method for translational failure analysis of landfills. The upper and lower bound solutions for the landfill stability, i.e., FSmax and FSmin, can be readily determined using this method. Using an average factor of safety, FSave, to replace the true factor of safety, FStrue, the differences between FSave and FStrue are within 5% for most considered cases. The solutions from the new method ensure that the waste strength is not exceeded anywhere within the waste mass. The calculated results agreed well with the results computed from the computer code PCSTABL6. The ability of the new method to calculate the translational failure of waste mass with a predetermined sliding failure face is demonstrated. Also, a waste filling sequence to keep the factor of safety above a stipulated value during the operation phase of the landfilling process can be generated.     

Completeness of ascertainment of prenatal smoking using birth certificates and confidential questionnaires: variations by maternal attributes and infant birth weight. PRAMS Working Group. Pregnancy Risk Assessment Monitoring System

Birth certificate data frequently are used to monitor the prevalence of smoking during pregnancy. The authors used a two-sample capture-recapture method to estimate the completeness of ascertainment of prenatal smoking on birth certificates and on confidential questionnaires in six US states. Completeness of ascertainment was also examined according to maternal attributes and infant birth weight. The samples included white women who delivered a live infant between 1993 and 1995 in one of six states (Alabama, Alaska, Georgia, Maine, South Carolina, or West Virginia) and who responded to a questionnaire mailed to them 2-6 months postpartum as part of the Pregnancy Risk Assessment Monitoring System. State-specific sample sizes ranged from 2,647 to 4,795. The completeness of ascertainment ranged from 70.6% to 82.0% using birth certificates and from 86.2% to 90.3% using confidential questionnaires. In all six states, the birth certificates' completeness of ascertainment varied by maternal education and infant birth weight, and the questionnaires' completeness varied by maternal age. Both birth certificates and questionnaires underestimated the true extent of smoking during pregnancy among these white women. Differential reporting by birth weights recorded on birth certificates would result in an overestimated association between low birth weight and prenatal smoking.     

A study on solutions for avoiding liquid segregation phenomena in thixoforming process: Part II. Net shape manufacturing of automotive scroll component

The most important problem regarding the thixoforming process is the prevention of the liquid segregation phenomena during deformation. Since the liquid is of eutectic composition in materials, the liquid segregation will result in significant or undesirable situation. In this work, thus, the thixoforming experiments with a die designed to fabricate a net shape scroll component using semisolid aluminum alloys were carried out successfully. The die filling patterns of semisolid materials (SSMs) by varying the process parameters, such as die temperature and pressing force, have been investigated. The hardness and wear resistance of the thixoformed scroll product were evaluated in terms of both rheological and microstructural points of view. Two key features of the solutions that need to avoid the liquid segregation in the thixoforming process are the following. (1) It was concluded that to improve the thixoformability and to reduce the possibility of defects, the liquid segregation should be controlled as the multistage variation of the pressing velocity during forming. (2) In addition, the ability to model the material flow characteristics, including the solid/liquid segregation during die filling, will be required. This modeling technology is currently under development.     

江铜贵溪冶炼厂企业数据库建设

本文介绍了江铜贵溪冶炼厂利用数据库相关技术,实现企业数据库数据的完整性、一致性和安全性.     

充填挡墙压力变化规律模拟试验研究

充填挡墙是将充填料浆封闭在采空区内实现预定功能的重要保障,研究充填挡墙在充填过程中的压力变化规律十分必要。从物理模拟试验入手,采用充填挡墙压力变化模拟试验装置,分析在充填过程中浓度、充填高度、脱水情况对充填挡墙压力变化的影响,并探究了快速充填与实际充填时充填挡墙压力差别。充填过程中尾砂浆体的脱水情况对充填挡墙压力变化影响较明显。模拟试验得到的规律与现场实测结果基本一致,可为矿山安全、经济地设计充填挡墙提供参考借鉴。     

Structural mechanism of oxygen implantation in the vanadium carbide lattice

Conclusions An investigation was carried out into the variation of the completeness of the elementary cell of the VC_xO_y phase forming during the progressive implantation of oxygen into the lattices of the carbides VC_0.7–0.9, and the types of solid solutions forming under these conditions were determined. The hypothesis is advanced that metal evolution in this process can be a result also of a redistribution of atoms within the matrix being formed, with the appearance of new elementary cells. In addition, the possibility cannot be ruled out of disproportionation reactions occurring during the oxidation of, inter alia, VC_x and VC_xO_y phases.Translated from Poroshkovaya Metallurgiya, No. 2(206), pp. 75–78, February, 1980.     

采场充填料浆流动与离析规律的试验研究

为研究采场充填料浆流动规律及充填料浆离析分层对充填体强度的影响规律,开展了充填料浆流动相似模拟试验及采场原位充填体力学强度测试试验,研究结果表明：单点下料时充填料浆流动终态坡面趋向于正态分布。流动过程中充填料浆产生离析分层现象,主要表现为充填体物料的粒径沿料浆流动方向呈先增大后减小的趋势,充填体强度沿料浆流动方向呈先减小后增大再减小的倒转“S”形趋势。采场原位充填体强度在下料口附近与标准试块强度接近,在采场中间位置附近的充填体强度最小,在距离下料点采场长度7/10左右的位置充填体强度达到最大值。研究成果能够为充填采场下料管的数量及位置设计提供依据,从而保证充填体的整体质量。     

碳酸盐溶液中富水充填材料的腐蚀及劣化机理

为了研究碳酸根离子对富水充填材料的影响,通过强度检测、扫描电镜观察、X射线衍射分析和红外光谱测试,分析富水充填材料在碳酸钠溶液中浸泡后的宏观及微观结构变化,并对其腐蚀及劣化机理进行探讨.富水充填材料在质量分数为10%的碳酸钠溶液中浸泡后,抗压强度随浸泡时间延长大幅度降低,浸泡90 d后抗压强度比标养28 d抗压强度降低72.5%,浸泡28 d后出现泥化现象.X射线衍射图谱显示,富水充填材料在质量分数为10%的碳酸钠溶液中浸泡后有碳硫硅钙石生成,且随浸泡时间延长碳硫硅钙石的生成量增大.红外光谱结果未发现[AlO₆]存在,证实在碳酸钠溶液中富水充填材料硬化体中钙矾石急剧减少,转变为烂泥状的碳硫硅钙石;碳硫硅钙石作为无胶结力物质,会对富水充填材料硬化体造成严重破坏,表明碳酸盐溶液对富水充填材料具有腐蚀作用.