可溶性盐复分解法碳酸钙制备影响因素研究

采用可溶性盐复分解法进行碳酸钙合成影响因素及其机理的研究。以正交试验法对合成温度、pH值、反应物浓度在碳酸钙合成中的影响进行探索,验证了温度以及pH值在合成反应中对产物晶型、形貌以及尺度有显著影响;使用周期键链理论(PBC)讨论了碳酸钙晶体方解石/文石共生现象;研究观察Mg2+对碳酸钙合成的影响,Mg2+作为能够稳定无定形碳酸钙前驱体(ACC)的金属离子,大量存在时碳酸钙形貌随nMg/nCa增大而变化,同时颗粒尺度变小。     

鳡鱼副产品制备鱼冻的研究

为提高鳡鱼加工副产品的利用率,本研究以鳡鱼骨、鱼皮、鱼鳞等为原料,采用提取、调味、成型等工艺制备鱼冻产品。经单因素实验获得鳡鱼冻质构(包括弹性和硬度)的可优化参数。正交实验结果表明,提取时酸化剂(柠檬酸∶醋酸=1∶1)3%(v/m)、氯化钠3%(m/m),调配时卡拉胶1.1%(m/m)鳡鱼冻产品的硬度为2403N,风味良好,氨基酸含量与鳡鱼肌肉组成类似、基本满足FAO/WHO的建议模式。     

装卸用直臂架多用途门机典型起升钢丝绳卷绕系统的分析与比较

通过详细地分析和比较已被上海振华重工(ZPMC)完成项目中3种典型的装卸用直臂架多用途门机的起升钢丝绳卷绕形式,总结出每种卷绕形式的特点和各自的适用条件,对今后提高装卸用直臂架门机的设计和制造的综合质量具有一定的指导意义。     

美国分区规划制度分析

介绍了美国分区规划的产生、发展历程及管理体系,分析了在美国的社会、经济及政治背景下,分区规划所出现的一系列经济、社会问题,并总结了美国分区规划对我国城市规划的影响。     

In-Situ Analyzing the Influence of Thermoelectromagnetic Convection on the Nucleation Ahead of the Advancing Interface During Directional Solidification

Sn-3wt%Pb alloy was directionally solidified without and with a 0.08T transverse magnetic field(TMF),and real-time recorded by in-situ synchrotron X-ray imaging.Results indicate that TMF shortened the distance from the location of nucleation to the advancing interface,and accelerated the growth rate of the equiaxed crystal,which caused the columnar-to-equiaxed transition(CET)finally.The thermoelectromagnetic convection(TEMC)in front of the interface and around the crystal’s dendritic branch should respond to changes of the distance and the growth rate.     

Electrochemical performance of LiVPO4F/C synthesized by different methods

LiVPO₄F/C samples were synthesized by one-step solid-state reaction and two-step solid-state reaction methods, respectively. The X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical performance tests were adopted to characterize the properties of LiVPO₄F/C. XRD results show that the LiVPO₄F/C samples prepared by one-step solid-state reaction method have the same triclinic structure (space group as that synthesized by conventional two-step solid-state reaction. SEM image exhibits that the particle size of LiVPO₄F/C prepared by one-step solid-state reaction method is smaller than that of the sample synthesized by two-step solid-state reaction. The improved electrochemical properties of the LiVPO₄F/C are attributed to the depressed grain size and enhanced electrical conductivity produced via one-step solid-state reaction method using oxalic acid as both reduction agent and carbon sources. AC impedance measurements also show that the LiVPO₄F/C synthesized by one-step solid-state reaction route significantly decreases the charge-transfer resistance.     

一种GPS信号载波跟踪技术

本文提出一种锁相环(PLL)与锁频环(FLL)相级联的 GPS 信号载波跟踪方法， 该方法兼顾了 PLL 的载波跟踪精度与 FLL 的动态适应性，经过验证，该方法可以实现对高动态信号的精确跟踪。     

多级油缸导向套装配问题及解决

油缸产品零件虽然不多,但由于导向套的装配精度直接影响产品的密封性和工作性能,因此对导向套的装配精度要求非常严,特别是煤机行业多级油缸导向套的装配。由于其工作时承载力大,且需要在潮湿的恶劣环境下工作,因此对其导向套的安装精度和密封性的要求更为严格。     

硬岩中的可重复使用抗爆洞室结构设计技术

在原岩中直接进行化爆模拟试验是研究地震耦合效应的重要方法,但存在爆心附近原岩介质状态改变或地震传播路径变化的问题,从而导致地震信号质量差、工程代价高。为此,提出了在地下洞室中构建可重复使用钢纤维混凝土衬砌结构的抗爆设计思路。采用数值模拟方法,对结构损伤破坏的高风险区域及破坏形式进行了预测;根据数值模拟结果,制定了针对性结构设计方案。在设计建设的密闭设施内重复开展了数百公斤级TNT当量化爆试验,通过爆后壁面破损情况对比、钻孔取样与钻孔摄像观测,证实多次爆炸未对衬砌与原岩界面产生明显影响;相似事件在同一台站的地震信号表现出了较高稳定性和重复性,证明该抗爆结构达到了预期设计目标。该工作可为类似抗爆设施建设提供工程实例与技术参考。     

Physical modeling and numerical simulation of electromagnetic stirring in a slab continuous casting mold

Through physical modeling and numerical simulation,the flow field in a slab continuous casting mold with electromagnetic stirring is measured under different casting parameters and stirring currents. To qualitatively evaluate the flow field in the mold,two indexes,i. e.,mold flux entrapment and velocity uniformity,are proposed.Based on these two indexes,some optimized stirring parameters under different casting conditions can be determined.