粉煤灰-酒糟混合基质的植物生长试验研究

利用粉煤灰和酒糟的理化特性,将二者按照一定比例配成混合基质,通过白花三叶草的盆栽试验,分析种植前后混合基质的理化特性及三叶草的生长情况,并检测基质和植株中的重金属含量.结果表明:当粉煤灰与酒糟的质量比为4:1时,基质最适合三叶草的生长,而且基质和植株体内的重金属含量均未超出国家标准.因此,可以将该基质作为矿区塌陷地的复垦基质.     

第15届国际选煤大会综述

国际选煤大会是全球煤炭界的重要会议，是国际选煤界最具权威性、最具影响力的专业盛会。目前，已有16个国家成为国际选煤大会组织的成员，中国于1972年加入国际选煤大会组织。2006年10月17日到19日召开的第15届国际选煤大会由中国煤炭工业协会和中国国际贸易促进委员会煤炭行业分会（商会）共同举办，主题为“煤炭洗选产业的发展和环保”。中国煤炭工业协会会长、中国工程院院士范维唐致欢迎辞，中国煤炭工业协会第一副会长、煤炭贸促会会长濮洪九主持了开幕式并参加了闭幕式。国家科技部、国有资产监督管理委员会和国家发展改革委员会的有关领导参加了会议，并做重要讲话。     

某型自动榴弹发射器身管铬层厚度研究

为解决某型35 mm自动榴弹发射器身管铬层设计存在合格率低和生产成本高的问题,对其身管铬层厚度进行研究。找出身管铬层厚度设计的缺陷,对其进行深入分析,提出将身管铬层厚度进行调整的方法,并以大量试验进行验证。结果表明:该方法既能缩短生产时间,降低镀铬溶液、水、电、气等物质消耗和生产成本,还能提高生产效率以及产品的合格率。     

Fish-scale-like nano-porous membrane based on zeolite nanosheets for long stable zinc-based flow battery

Zinc-based flow batteries receive widespread attention due to their advantages of low cost and high energy density. However, zinc dendrites are easy to appear during the charge process, pierce the membrane and thus destroy the battery, which seriously restrict its further development. In this article, MFI-type zeolite nanosheets (ns-MFIs) with high mechanical strength and hydrophobicity are in situ introduced to porous polymer membranes, which spontaneously form turnup fish-scale-like structure through the one-step phase inversion/surface segregation process. This special structure well disperses mechanical energy to provide effective protection characteristics to resist the penetration of zinc dendrites, and meanwhile promotes the uniform zinc depositions on the electrode by alleviating the water migration and accelerating zincate ion diffusion, so as to prolong the cycle life of the battery for more than 600 cycles, which is 4 times and 2.5 times longer than the commercial Nafion 212 and pristine porous polymer membrane, respectively. Moreover, the sub-nano size pores and high-aspect-ratio of ns-MFIs afford membranes extra ion sieving ability and transport area for the charging-balancing ions OH⁻ to ensure superior battery performance, delivering an average coulombic efficiency (CE) of ~98.5%, voltage efficiency (VE) of ~83.2%, and energy efficiency (EE) of ~81.9% at 80 mA/cm².     

添加浮选镁砂颗粒和Al2O3细粉对方镁石-尖晶石砖性能的影响

以烧结镁砂、浮选镁砂、电熔镁铝尖晶石和煅烧Al₂O₃细粉为主要原料,以木质素磺酸钙为结合剂,经混练、成型、1 650℃烧成制备了方镁石-尖晶石砖,主要研究了以浮选镁砂颗粒替代普通烧结镁砂颗粒以及在此基础上外加不同量煅烧Al₂O₃细粉（质量分数分别为0、3%和5%）对方镁石-尖晶石砖性能的影响。结果表明：1)以浮选镁砂颗粒替代普通烧结镁砂颗粒制备的方镁石-尖晶石砖,显气孔率和常温耐压强度降低,体积密度、抗热震性、高温强度和高温韧性提高。2)在以浮选镁砂颗粒替代普通烧结镁砂颗粒制备的方镁石-尖晶石砖中,随着煅烧Al₂O₃细粉引入量的增多,显气孔率和常温耐压强度降低,体积密度、抗热震性、高温强度和高温韧性提高。     

固溶冷却介质对GH4720Li合金组织和性能的影响

γ'相的形貌对GH4720Li合金的性能起着十分重要的作用。固溶淬火时高冷速可以增加基体的过饱和度,有利于获取细小的γ'相组织,然而过高的冷速容易导致工件淬火开裂。因此,工业生产中选择适当的冷却介质控制固溶淬火的冷却速度就显得尤其关键。采用光学显微镜(OM)、扫描电镜(SEM)等手段研究了不同冷却介质对GH4720Li合金组织和性能的影响。结果显示,固溶冷却介质对GH4720Li合金的晶粒尺寸、一次γ'相形貌和数量无影响;水冷试样中二次γ'相的数量最少、三次γ'相的尺寸最小;水溶性淬火剂(20%浓度)冷却后的样品中三次γ'相的尺寸最大,室温、高温拉伸的屈服强度略低于其他样品。     

特种冶金生产流程的发展趋势

特种冶金是生产高端特殊钢和特种合金的主要手段,代表了一个国家的工业化发展水平,一直是国内外冶金技术竞争的制高点.本文首先回顾和总结了传统特种冶金技术的种类和主要生产流程;其次,概述了典型特殊钢品种的特种冶金生产流程;再次,对典型特钢企业的特种冶金生产流程进行了介绍;最后,对特种冶金生产流程的未来发展趋势作出预测.新技术将进一步促进特种冶金生产流程的变革与发展.     

Influence of Five-Year Degradation on Mechanical and Tribology Properties of Ultra-High-Molecular-Weight Polyethylene

Ultra-high-molecular-weight polyethylene (UHMWPE) has been the most commonly used bearing material in total joint replacement. The degradation of UHMWPE components has a notable influence on its mechanical properties. UHMWPE samples were immersed in simulated fluid (SBF) up to 5 years and the change in chemical composition and mechanical and wetting properties was investigated. It was found that the oxygen/carbon (O/C) ratio and crystallinity increased from 14.5 and 50.0% before immersion to 52.8 and 60.7% after immersion in SBF for 5 years, respectively. These resulted in a reduction in ball indentation hardness, scratch coefficient, peak load, and contact angle by 35.7, 21.0, 15.8, and 14.0%, respectively, after 5 years of immersion. The steady-state friction coefficient and wear rate increased 83.3 and 43.8%, respectively, after immersion in SBF for 5 years. The preliminary study indicated that the scratch test was an effective method to evaluate the surface performance of UHMWPE after short-term degradation, and small punch test was often used to assess the bulk properties of UHMWPE after long-term degradation.     

Numerical study of geometrical effects on the performance of an H-type cylindrical resonant photoacoustic cell

We have numerically studied the geometrical effects on the performance of an H-type cylindrical resonant photoacoustic cell, composed of one resonator and two symmetrical buffer cylinders, by performing simulations on the generation of acoustic waves in the cell. Here, the acoustic response (pressure), resonance frequency and quality factor are calculated for the cell performance, while the lengths and diameters of both resonator and buffer cylinders are considered for the geometrical parameters or dimensions. Our calculation solves linearized forms of the continuity equation, Navier-Stokes equation, energy equation, and equation of state using a finite element method under an assumption that the heat addition due to the laser passage and thus the variations in the velocity, pressure and temperature fields inside the cell are small enough. First, we performed a statistical analysis using a design of experiment method to evaluate the relative impacts of the cell dimensions on the acoustic response. Subsequently, we performed a parametric study to quantify the cell performance with the dimensional variations. Our results, along with the response surface methodology, provide guidance for a systematic design optimization of the cell for the best acoustic response. The approach in this study may be applied to the design of various types of resonant photoacoustic spectroscopy devices.     

Finite element analysis of the impact of liner thickness and hydrodynamic limit on the penetration depth of a shaped charge warhead

In this work, an identification method for the hydrodynamic limit of shaped charge jets (SCJs) is proposed using numerical analysis. To identify the hydrodynamic limit, we consider situations where two targets of the same density but different strengths are penetrated by the same SCJ. As a result, the SCJ corresponding with the hydrodynamic theory is a jet region with a velocity larger than 4 km/s. In addition, an investigation based on the hydrodynamic limit and liner thickness indicates that the penetration capability before and after the hydrodynamic limit improves as apex thickness decreases and base thickness increases, respectively. The simple and clear identification of the hydrodynamic limit is expected to be possible using the proposed method. Accordingly, a selective and organized liner thickness design can be developed.