High-Throughput Screening for Phase-Change Memory Materials

Phase change memory (PCM) is an emerging non-volatile data storage technology concerned by the semiconductor industry. To improve the performances, previous efforts have mainly focused on partially replacing or doping elements in the flagship Ge-Sb-Te (GST) alloy based on experimental “trial-and-error” methods. Here, the current largest scale PCM materials searching is reported, starting with 124 515 candidate materials, using a rational high-throughput screening strategy consisting of criteria related to PCM characteristics. In the results, there are 158 candidates screened for PCM materials, of which ≈68% are not employed. By further analyses, including cohesive energy, bond angle analyses, and Born effective charge, there are 52 materials with properties similar to the GST system, including Ge₂Bi₂Te₅, GeAs₄Te₇, GeAs₂Te₄, so on and other candidates that have not been reported, such as TlBiTe₂, TlSbTe₂, CdPb₃Se₄, etc. Compared with GST, materials with close cohesive energy include AgBiTe₂, TlSbTe₂, As₂Te₃, TlBiTe₂, etc., indicating possible low power consumption. Through further melt-quenching molecular dynamic calculation and structural/electronic analyses, Ge₂Bi₂Te₅, CdPb₃Se₄, MnBi₂Te₄, and TlBiTe₂ are found suitable for optical/electrical PCM applications, which further verifies the effectiveness of this strategy. The present study will accelerate the exploration and development of advanced PCM materials for current and future big-data applications.     

双核镍配合物[Ni_2(baba)_2(N_3)_2(CH_3OH)_2]的合成、晶体结构和热重分析

以邻氨基苯磺酸缩吡啶-2-甲醛席夫碱(Kbaba)和NaN3为配体,在水-甲醇混合溶剂中与Ni(AcO)2·4H2O反应,得到了一种双核配合物[Ni2(baba)2(N3)2(CH3OH)2](1)。单晶衍射结果表明:配合物(1)属于单斜晶系,C2/c空间群。配合物(1)是中心对称的,它是由一对μ1,1方式桥联的N-3键合两个镍离子而形成的双核配合物。每个镍离子六配位于一个baba-配体的吡啶氮原子、亚氨基氮原子、磺酸基氧原子、一个配位水分子的氧原子以及两个桥连N-3的氮原子形成畸变的八面体构型。     

基于深对流云的夜间微光传感器定标技术

NPP(National Polar-orbiting Parternership)卫星于2011年10月28日发射升空,其上搭载的VIIRS(Visible Infrared Imaging Radiometer Suite)传感器包含DNB(Day Night Band)波段,该波段采用三增益设置,可在白天、晨昏甚至夜间实现地球观测.其中,在夜间月光条件下,主要采用高增益,定标实现较为困难.以此为目的,首次提出了基于深对流云的夜间微光传感器替代定标方法.将月亮辐射模型引入到SCIATRAN中,实现了全天候的辐射传输计算,并利用该改进的辐射传输模式,通过确定深对流云光学属性、地表特性及大气廓线等的参考值,对接收大气层顶反射辐射进行敏感性试验,分析得到主要影响因子为云光学厚度COT(Cloud Optical Thickness)与有效粒子半径Re(Effective Radius),且利用固定参考值得到最大模拟误差小于5%.为了检验该替代方法的可行性,通过改进的辐射传输模式,对2012年08月~2013年01月共6个月夜间DNB数据所确定的深对流云替代目标像素进行辐射传输模拟,结果表明基于深对流云的替代定标方法效果较好,基于日变化的辐射不确定度在±10%之内,可实现对DNB夜间高增益阶段的直接辐射定标.     

水冷式表面冷却器优化建模

通过分析比较,取最低年综合费用作为优化设计目标函数,并在一定的约束条件下,针对某型号表面冷却器,建立年综合费用与表面冷却器结构参数之间的函数关系,即表面冷却器优化设计数学模型,为实现表面冷却器及相关部件的合理匹配提供了一定的参考数据。     

Optimal injection velocity profiling

Recently, manufacturers of thermoplastic injection moulding machines have developed controllers with programmable velocity control. The speed of the ram can typically be varied in as many as ten zones during the injection process to establish a velocity profile. This velocity profile however, is determined by trial and error. Some controller manufacturers have made claims about injection velocity profiling, however, actual experimental data is not available to confirm them. In this paper, some experiments were conducted in order to verify the effectiveness of these claims. The results of these experiments indicate that injection velocity control has little effect on reducing or eliminating the problems for which the claims are made.     

阿姆河气田天然气脱硫脱碳MDEA吸收塔工艺的优化

针对阿姆河气田天然气脱硫脱碳过程中MDEA吸收塔工艺落后,导致贫胺液进料量调控不精确,H_2S含量无法达到或超出设计指标的情况。应用K-SPICE软件对MDEA吸收塔进行动态模拟,在贫胺液进料环节增加了H_2S流量与贫胺液进料量的反馈调节,通过分析优化结果数据和优化前后经济性比较得出优化方案切实可行。     

电厂脱硫系统GGH结垢原因分析及解决方案

粤电集团下属电厂湿法烟气脱硫系统在连续运行过程中普遍出现了GGH结垢堵塞的问题.对GGH垢样进行了取样分析后,找出GGH堵塞的主要原因.结果表明:结垢主要来自于吸收塔的石膏浆液和烟尘.通过实验得出最佳的控制方案,采取相应措施后取得了很好的效果,可供电厂脱硫工程参考借鉴.     

高定时精度的双屏蔽电容式脉冲传感器的设计

基于叶尖定时测振原理,设计了用于叶尖定时测量的双屏蔽电容式脉冲传感器,并结合预处理电路建立了传感器的控制论模型,对电路系统的带宽计算做了优化.理论计算与仿真表明,该脉冲传感器带宽大、响应快;同时实验结果也表明,传感器具有很高的信噪比和很强的抗干扰能力,能够满足高精度叶尖定时传感器的要求.     

γ-聚谷氨酸的生物合成及应用

聚谷氨酸是一种可降解的生物高分子 ,可由微生物生物聚合而得到。综述了聚谷氨酸的生物合成方法、高吸水性聚谷氨酸制备技术以及在农业、医药、化工等领域的应用     

热熔凝聚法加工农药悬浮剂研究

介绍了采用热熔凝聚法对加工二氯喹磷酸、氟虫睛、乙霉威悬浮剂的试验结果，并测定了制剂的粒度分布、冷贮、热贮稳定性等理化性质。该法工艺简单、加工方便、节省能源、工业上切实可行。