铜精矿矿样品加工、试样处理、样品保存过程中最优条件探索

本文考察了不同制样工具对样品粒度、均匀性的影响、硫酸加入对Cu%测试结果的影响及样品保存方式对测试结果的影响,通过试验找到了各环节操作常见问题,并就问题点提出相应的解决方法,以提高检测结果的准确性。     

复杂岩质边坡的岩体力学参数变化规律研究

根据工程实际情况,对复杂岩质边坡的地质条件进行分析,研究其岩体力学参数。运用试验方法和数值模拟方法分别研究了边坡开挖卸荷过程中岩体参数的量化,并通过FLAC数值模拟研究岩体参数的动态变化规律,将模拟结果与试验结果进行比较并进行修正。修正后的结果为边坡稳定性分析提供依据。     

Development of a model for the simulation of the transfer of surface structure in the temper-rolling process

In the temper rolling process the effect of transferring the roll-surface structure to the steel sheet is purposely used to adjust a defined sheet-surface structure required for further processing. At the moment four different texturing techniques (SBT, EDT, EBT, LT) are available for the production of specified roll-surface structures; these techniques are based on two fundamental mechanisms; plastic deformation and local melting. The objective of the investigation presented in this paper is to analyze the transfer behaviour specific to the texturing technique used and, in addition to that, to develop a model for the simulation of these transfer characteristics. For this purpose in the first part the results of a comparative study on the basis of rolling tests on an industrial temper mill are presented. These results do not only point out the basic transfer mechanisms – penetration processes and reverse extrusion phenomena – but beyond that also lead to an explanation of the transfer behaviour specific to the texturing systems by the application of similarity numbers (substitute profile model). Possible reasons for the different transfer behaviour are on the one hand wear effects and on the other hand process-induced characteristics of the structure itself (e.g. isolated lubrication pockets). On the basis of these results in the second part a model is developed to simulate the transfer characteristics by the application of the finite element method (FEM).     

Methods for the analysis of binary outcome results in the presence of missing data.

An important, frequent, and unresolved problem in treatment research is deciding how to analyze outcome data when some of the data are missing. After a brief review of alternative procedures and the underlying models on which they are based, an approach is presented for dealing with the most common situation—comparing the outcome results in a 2-group, randomized design in the presence of missing data. The proposed analysis is based on the concept of "modeling our ignorance" by examining all possible outcomes, given a known number of missing results with a binary outcome, and then describing the distribution of those results. This method allows the researcher to define the range of all possible results that could have resulted had the missing data been observed. Extensions to more complex designs are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

考虑微观组织演变的多道次热轧有限元模拟

通过MARC提供的开放接口和相应子程序系统,集成多尺度的计算模块,在MARC2010和FOR-TRON10.1平台对某钢厂中厚板热轧生产线某生产牌号产品的生产实现考虑微观组织演变的有限元数值模拟计算。对模拟结果中各场变量（再结晶分数、晶粒度和轧制力）在不同轧制道次的变化规律,进行了详细分析。对本文模型和周纪华模型的相应轧制力计算值与现场实测值进行了对比分析。进一步验证了本文的模拟计算是科学合理的。     

平面应变镦粗问题的变分分析

应用希尔分析金属加工过程的一般方法计算了平面应变镦粗问题的载荷和自由表面的鼓形形状并将分析结果与其它理论分析结果及有关实验进行了对比．结果表明，应用希尔法所获得的结果与其它理论分析结果及实验符合较好，但结果的精度较其它理论方法没有改善．     

On the usefulness of epitaxy experiments in evaluating interface models

New results on low energy interfaces for the system gold on sodium chloride are presented together with a short review of the various versions of the sphere-plate technique which are used to study interface systems. The observed low energy orientation relationships as well as those recently found for the systems silver on sodium chloride and silver on silicon are compared with preferred orientations observed in epitaxy experiments. It is concluded that results for epitaxy are extremely useful when evaluating interface models for their predictive power.     

On the oxidation of cyanides in the stack region of the blast furnace

Computed results are reported on the oxidation of KCN particles carried by blast furnace gas through the stack region of the furnace. The calculations were performed on the assumption that the oxidation process is mass transfer controlled, but proper allowance was made for the variable CO/CO₂ ratios and temperatures to which the particles are exposed during their passage through the stack. The results of these calculations show that for cyanide particles in the range 0.02 to 0.1 cm in diameter the system may be extremely sensitive both to the temperature profiles and to the CO/CO₂ ratios within the stack; thus the control of these parameters could provide a means of controlling cyanide emissions.     

Reduction of the current of injury leaving the amputation inhibits limb regeneration in the red spotted newt

Motion results in various artifacts such as blurring and streaks in clinical imaging of subjects based on reconstruction from projections. We model subject motion-induced artifacts due to scaling, translational and rotational motion. A correction algorithm based on the Ludwig-Helgason consistency conditions is derived here. These conditions are satisfied whenever the projection data are consistent. We apply the algorithm to simulated data collected on linogram (LR) and projection reconstruction (PR) geometries, and to real PR geometry data, in magnetic resonance imaging (MRI). The results show that motion-induced in-plane, interview artifacts can be reduced with application of the algorithm. The algorithm is general enough to be applied to certain other cases arising in tomographic imaging.     

An investigation of the effects of ductile-layer thickness on the fracture behavior of nickel aluminide microlaminates

This article presents the results of a combined experimental and analytical study of the effects of ductile-layer thickness on the initiation toughness and resistance-curve behavior of nickel aluminide composites that are reinforced with ductile V and Nb-15Al-40Ti layers. The initiation toughness and specimen-independent steady-state toughness values are shown to increase with increasing layer thickness. Stable crack growth and toughening in the crack-arrestor orientation are also attributed to crack bridging and the interactions of crack tips with the ductile layers. The overall toughening in the microlaminates is modeled by superposing the shielding contributions due to crack bridging on the stress-intensity factor required to promote renucleation ahead of the first ductile layer ahead of the precrack. The implications of the results are also discussed for the design of ductile phase-toughened microlaminates.     

Appearance of T cells in the bursa of Fabricius and cecal tonsils during the acute phase of infectious bursal disease virus infection in chickens

Presteady and steady-state kinetic results on the interactions of a wild-type, and the mutant glucoamylases Trp52-->Phe and Trp317-->Phe, from Aspergillus niger with maltose, maltotriose and maltotetraose have been obtained and analyzed. The results are compared with previous ones on the mutants, Trp120-->Phe and Glu180-->Gln, and with results obtained from structure energy minimization calculations based on known three-dimensional structural data. All results are in accordance with a three-step reaction model involving two steps in the substrate binding and a rate-determining catalytic step. Trp317 and Glu180 belong to different subsites, but are placed on the same flank of the active site (beta-flank). The Trp317-->Phe and the Glu180-->Gln mutants show almost identical kinetic results: weakening of the substrate binding, mainly caused by changes in the second reaction step, and practically no change of the catalytic rate. Structure energy minimization calculations show that the same loss of Arg305 and Glu180 hydrogen bonds to the substrate occurs in the Michaelis complexes of each of these mutants. These results indicate that important interactions of the active site may be better understood from a consideration of its flanks rather than of its subsites. The results further indicate differences in the substrate binding mode of maltose and of longer substrates. Trp52 and Trp120 each interact with the catalytic acid, Glu179, and are placed on the flank (alpha-flank) of the active site opposite to Trp317, Arg305 and Glu180. Also the Trp52-->Phe and Trp120-->Phe mutants show kinetic results similar to each other. The catalytic rates are strongly reduced and the substrates are bound more strongly, mainly as a result of the formation of a more stable complex in the second reaction step. All together, the substrate binding mechanism seems to involve an initial enzyme-substrate complex, in which the beta-flank plays a minor role, except for maltose binding; this is followed by a conformational change, in which hydrogen bonds to Arg305 and Glu180 of the beta-flank are established and the correct alignment on the alpha-flank of Glu179, the general acid catalyst, governed by its flexible interactions with Trp52 and Trp120, occurs.     

Relations between the form of the vocal tract and the acoustic characteristics of the French vowels

The distribution inside the vocal tract of certain acoustic parameters (volume velocity, acoustic pressure, stored energy) is calculated for the French vowels. Calculations are made using a simulated lossy transmission line model of the vocal tract. The obtained results are used to study the relation between the acoustic characteristics of these vowels and the corresponding articulatory dimensions. Three aspects of this relation are developed: (1) the "affiliation degree" of each formant with different sections of the vocal tract; (2) the sensitivity of each formant frequency to small changes of the vocal tract area function, and (3) the contribution of each part of the vocal tract to formant damping for each of the distributed losses. The effects of radiation impedance and wall vibration on these relations are evaluated. Use of these results is possible in the fields of speech analysis and vocal tract modeling.     

The effect of the lower stress level on the cyclic creep behavior of an ods superalloy

Cyclic creep and stress rupture results are reported and discussed as a function of the lower applied load for INCONEL MA6000, which is a mechanically alloyed oxide dispersion strengthened (ODS) and γ’ precipitation strengthened nickel-base superalloy. In prior work, very large decreases in the effective minimum cyclic creep rate, based on time at maximum load, were found to occur for cyclic creep testing using a lower load near zero. The present results show that this decrease in creep rate depends on the value of the lower load. As the lower load increases, the cyclic creep rate increases proportionally, but remains less than the corresponding static creep rate. The values of the cyclic creep rates are shown to be related to the magnitude of the anelastic strain recovery occurring during the lower load portion of the cyclic creep test. The results are also used to improve on the anelastic relaxation model for cyclic creep of materials with strong pinning points.     

厚板取样部位对低温冲击试验结果的影响探究

针对在板厚1/2处、1/3处、1/4处、1/5处、1/6处和1/8处取样加工成冲击试样进行低温冲击试验,研究了厚度方向上不同取样部位对厚板低温冲击试验结果的影响。得出冲击结果与不同取样部位的变化曲线图,发现厚度方向上不同取样部位对冲击结果有一定影响,随着取样位置从钢板表层到芯部的变化过程中,冲击值从高逐渐降低。     

The results of and outlook for the scientific and practical activities of the specialists in the institutions of the State Epidemiological Health Service of Chuvashia]

The authors analyze the results of using blood substitute made on the basis of gelatin and give a comparative characteristic of different colloid blood substitutes on the basis of dextran, gelatin, starch and polyethylene glycol. Advantages of Gelafusin are shown.     

Integral equations of the theory of liquid in the study of hydration of macromolecules

Based on the numerical algorithm proposed by us in [1] for solving integral equations of the theory of liquids in the RISM approximation we calculate all of the solvent-solute atom-atom correlation functions for a fragment of the DNA duplex d(GGGGG) in infinitely diluted aqueous solution. The obtained results are compared with available experimental data and results from computer simulations.     

On the kinetics and mechanism of the dissolution of pyrite in the presence of Thiobacillus ferrooxidans

In this paper, the results of a study of the leaching of pyrite in the presence and absence of bacteria at the same solution conditions are summarised. These results indicate that the leaching of pyrite occurs at a higher rate in the presence of bacteria than in the absence of bacteria. Analysis of the rate of reaction as a function of concentration indicates that the order of reaction with respect to ferric ions is the same in the presence and the absence of bacteria. However, the order of reaction with respect to H⁺ is −0.5 in the absence of bacteria, and −0.39 in the presence of bacteria. The results of a study of the mixed potential of pyrite are also presented. These results indicate that the mixed potential of pyrite decreases with time in the presence of bacteria, while it is constant in the absence of bacteria. A detailed mechanism of the leaching of pyrite in ferric sulphate solutions is presented, and this theory is used to interpret the results. It is argued that the effect of the bacteria on the rate of leaching and on the mixed potential is not consistent with the direct contact mechanism of bacteria leaching. Instead, it is shown that the results can be explained by an increase in the pH at the mineral surface as a result of bacterial activity. This means that the increase in the leaching rate is a result of the indirect contact mechanism.     

Discharge and the Eccentricity of the Hopper Influence on the Silo Wall Pressures

The objective of this work is to perform an analysis of pressure distributions in grain silos for both the discharge and static conditions with eccentric outlets. To this end, the commercial ANSYS program, based on the finite-element method is employed. In this paper, results are presented for a silo with a height of 10.5 m (cylinder height 8 m, base cone height 2.5 m), a silo radius of 3 m, and an outlet radius of 0.5 m. Outlet eccentricity ranged from 0% (central outlet) to 100% (maximally eccentric outlet, tangential to the silo cylinder). Based on the results, this paper proposes new methods of analyzing silo discharge and the influence of outlet eccentricity. The discharge model combines both dilatancy and type of discharge effects. 3D models were developed to analyze the eccentricity of the outlet. The results are compared with previous research data and with standard design guidelines.     

钢管三辊冷斜轧的轧辊辊型设计

根据钢管冷斜轧过程的变形特点，建立了辊型设计系统。把辊型设计的结果作为初始参数，由刚塑性有限元分析成型过程，将速度场、应变和应力反馈到辊型设计系统，调整辊型设计的初始参数，绘制出适应钢管冷斜轧工艺要求辊型图。