1-甲基-3,4,5-三硝基吡唑的结晶热力学

利用重力法测定了1-甲基-3,4,5-三硝基吡唑(MTNP)在不同溶剂中的溶解度,采用Apelblat方程和vant′t Hoff方程拟合了溶解度数据,估算了MTNP的标准溶解焓、标准溶解熵、标准吉布斯自由能、固-液表面张力和表面熵因子。通过对比溶解度,选用苯、甲醇和无水乙醇作为溶剂分别对MTNP结晶并且进行产品表征。结果表明,MTNP的溶解度随温度的升高而增加;Apelblat方程和vant′t HoffF方程计算的溶解度值与实验值的平均绝对百分比偏差均小于5.18%,其中Apelblat方程对实验数据的关联结果较优;用电子显微镜观察无水乙醇作溶剂结晶得到的产品形貌规则且统一,其撞击感度为68%,激光粒度仪测试产品粒度均匀性较好。     

Preparation and Properties of PBXs Based on FOX-7 in Controlled Fragmentation Warhead Application（英）

Polymer bonded explosive(PBX)formulations were successfully prepared in the laboratory scale containing 1,1-diamino-2,2-dinitroethene(FOX-7)and hexogen(RDX)as brisant high explosives and different binder types of polyurethane(PU)based on glycidyl azide polymer(GAP) and hydroxyl-terminated polybutadiene(HTPB) as an energetic and inert polymeric binder respectively.Casting technique was used for the preparation of different PBX formulations based on FOX-7/RDX and PU(GAP/HTPB)with 14% binder.The sensitivity to different initial impulses and performance characteristics of the explosive and lethal zone of the tested controlled fragmentation warhead by the fragmentation warhead assessment test(arena test)were studied,in which the arena test was carried out with a controlled fragmentation warhead made from Ck45 steel,with dimensions(100 mm length,30 mm outer diameter and 3 mm thickness).Results show that PBXGF4 has lower sensitivity to impact and heat than those of PBXGR4 by 188.4% and 3.2% respectively.Its friction sensitivity is the same as that of PBXGR4.It has better performance,in which detonation velocity increases by 2.1% and brisance increases by 0.5% when compared with those of PBXGR4.It was concluded that PBXGF4 which based on FOX-7 bonded with PU/GAP matrix has good characteristics as PBX,specially in the sensitivity to impact and can be applied for replacing PBXs based on RDX in the advanced PBXs for low sensitive fragmentation warheads.     

"回弹-超声-拔出"综合法检测混凝土强度

针对张家口地区常用的混凝土强度等级(C15、C20、C25、C30、C35、C40),进行28天、42天、56天三个龄期的标养和同条件养护的超声、回弹及后装拨出法检测试验。天归出“回弹一超声一拔出”综合法检测混凝土强度公式,通过实际工程验证,天归公式具有较高的检测精度。     

多轴超声C扫描系统在车辆负重轮检测中的应用

采用多轴超声水浸C扫描系统检测车辆负重轮的内部缺陷,对扫描工艺参数、曲面路径快速编制进行了研究,获得了最佳检测工艺参数及快速编制曲面跟踪路径方法。结果表明,曲面跟踪C扫描检测是车辆负重轮理想的检测方法,不仅有利于缺陷的检出,而且检测结果准确、检测效率高,适合大批量作业。     

基于早龄期超声测试的堆石混凝土工程质量检测EI北大核心CSCD

从早龄期开始采用超声波对大尺寸自密实混凝土和堆石混凝土进行了对比测试,并基于黏弹性介质波动理论从纵波波速测量结果中分离出材料的黏性特征参数,用于分析堆石混凝土的浇筑状态,评价堆石混凝土的施工质量.结果表明:由于堆石混凝土内部结构复杂,仅依靠代表性体积单元的超声波速均值和变异系数难以对堆石混凝土的浇筑质量做出可靠的评价,因而需要进行高密度的分层检测;应用材料的黏性特征参数进行分析判断时,有可能采用较少的测线完成检测,这在工程实践中是更具有应用价值的方法.应用早龄期超声测试的方法有助于克服由于代表性单元尺寸过大给堆石混凝土工程质量评价带来的困难.     

Progress towards a methodology for high throughput 3D reconstruction of soot nanoparticles via electron tomography

The aim of this work is to make progress towards the development of 3D reconstruction as a legitimate alternative to traditional 2D characterization of soot. Time constraints are the greatest opposition to its implementation, as currently reconstruction of a single soot particle takes around 5–6 h to complete. As such, the accuracy and detail gains are currently insufficient to challenge 2D characterization of a representative sample (e.g. 200 particles). This work is a consideration of the optimization of the steps included within the computational reconstruction and manual segmentation of soot particles. Our optimal process reduced the time required by over 70% in comparison to a typical procedure, whilst producing models with no appreciable decrease in quality.     

弹药筒超声自动检测方法与系统

提出了一种基于弹药筒下母线入射的恒定横波折射角方法,实现对不同规格弹药筒的微细裂纹检测,通过仿真和实验验证检测的可靠性。设计了用于弹药筒等小径筒体的多工位高速超声自动化检测系统,分析检测系统中缺陷信号和干扰信号的特征,提出一种扫描信号滤波报警算法,最终实现了弹药筒上料、检测、分选全过程自动化。结果表明,该系统能检测的最小缺陷深度为0.05 mm,检测速度可达1 200件/h,误判率仅为1％。     

Experimental investigation of tool wear and machining rate in rotary ultrasonic machining of nickel alloy

Nickel alloys possess the excellent potential at high temperature and resistance to oxidation/corrosion owing to its high nickel content. These materials necessitate non-traditional machining methods. The rotary ultrasonic machining (RUM) process comes into existence as a superior alternative to the conventional machining of nickel alloys. The processing of these alloys using RUM needs attention. This article details the multi-response optimization in RUM of nickel alloy using the desirability concept. The present work is carried out with two shapes of the tool: (i) Plain tool and (ii) lateral slotted tool. During RUM, the process parameters—power rating tool rotation, abrasive diamond grit size and feed rate are varied. Compared with the plain tool, the lateral slotted tool shows the more efficient machining rate (MR) with less tool wear (TW). The micro-graphs disclose the mechanism of MR and TW during RUM.     

Laser Zone Melting and microstructure of waveguide coatings obtained on soda-lime glass

This study presents a Laser Zone Melting method with potential for producing planar waveguides at large scale, based on the surface coupling of two chemically compatible glass layers which exhibit distinct indices of refraction. The method is based on a recent patent, particularly applicable to process glass and ceramics with low thermal shock resistance. Glass coatings containing 76.24% by weight PbO are thus here reported, as obtained by this method on commercial soda-lime planar glass substrates. Their higher indices of refraction (1.58 vs 1.52 for commercial soda-lime glass) result in attractive waveguiding potential, as demonstrated with measurements using focused light from a He-Ne laser beam. Scanning and transmission electron microscopy studies reveal excellent integration and compatibility between the observed coatings and substrates, where diffusion in the proximity of the interface was studied by EDS analysis. Crystalline phases have not been found within the coating, or within the substrate, as concluded from the absence of Bragg-peaks in XRD experiments.     

加拿大白桦地致密气储层定量表征技术

以加拿大白桦地大型致密砂岩气田的研究为基础,梳理了致密气开发过程中需要评价分析的5大品质特性,提出了表征致密气储层特征的关键参数,确定了适用研究区的致密气储层定量表征和评价技术,形成了一套指标体系:多旋回精细等时地层格架和砂体叠置结构特征分析技术以确定储层空间展布;TOC测井参数地质统计定量技术以确定有机质丰度;岩心"四性"关系标定与序贯高斯模拟的储层物性定量表征技术以确定储层物性分类级别;基于岩心应力实验和测井解释的岩石脆性指数综合判定技术以确定岩石可压性;与压裂水平井产量相关的多参数组合综合评价技术以确定有利布井区;井下微地震监测技术定量用以表征人工裂缝、优化井位部署;水平井分段压裂优化技术确定最佳压裂段数、缝间距等参数,落实分段压裂水平井单井控制体积,确定单井控制储量。通过储层和裂缝综合研究不断优化致密气藏开发井网,其中大规模水平井压裂是致密气高产的有效保障,这些技术的现场应用也取得了显著的效果。