关于五四式手枪射击弹壳弹底窝痕迹特征变异的实验研究

通过实验研究,指出枪弹装药量、初速、膛压对射击弹壳弹底窝痕迹的影响和痕迹变化。提出采取拨弹机改变发射药量的方法,以获取弹底窝痕迹不同变化的比对样本,可为检验变化较大的弹底窝痕迹创造条件。     

爆炸冲击波作用下液体抛撒二次破碎的实验研究

本文采用高速摄影的方法拍摄了不同实验条件下液体抛撒的实验图片，实验结果表明：爆炸冲击波作用下液体颗粒产生二次破碎需一定的条件，不同的因素如液体密度、装盛液体量、装药量、表面张力等对液体抛撒二次破碎都产生显著影响。     

大学生心理压力对心理健康影响的实证研究

以上海市高校560名在校大学生为被试，通过问卷法，研究不同性别、专业大学生心理压力的差异以及大学生心理压力与心理健康的关系。结果发现：大学生的学习压力、生活压力、发展压力、社交压力、家庭压力存在显著的性别差异和专业差异；大学生自卑、社交攻击、性心理障碍、偏执、依赖、冲动、精神病倾向存在显著的性别差异；大学生的学习压力、生活压力、发展压力、社交压力、家庭压力与心理健康各维度呈显著正相关；生活压力、家庭压力、社交压力对大学生心理健康具有显著的影响。     

掏空银行:我干的事惊天动地!

枪弹、12.7×99mm枪弹。但在枪弹:6462,火箭枪:5824,飞行稳定性:3324,改进设计:1785,射击精度:1609,表示方法:1576,装药量:1274,军事演习:1181,黑火药:1045,弹壳:939枪弹:8428,火箭枪:4057,弹壳:1595,壳长:1550,飞行稳定性:1154,口罩:1152,身管:1074,尾翼:796,斜孔:705,弹头:672,装药量:571,表示方法:569,黑火药:528,射击精度:495,孔径:449,军事演习:427,改进设计:409,弹体:400,武器:388,道具:375碘鹭~馨一蕊、图2装在弹托里(右〕和未装弹托(左)的普雷;每弹头 空弹尖膨胀变形后折断,并与弹头体分别继续向更深处侵彻·图1普雷梅弹头膨胀变形…     

减缓就业压力,提升大学生主观幸福感

近年来,面对日益严峻的就业形势,不论是大学毕业生还是低年级大学生都感受到越来越多的就业压力,可以说就业压力已经严重影响着大学生的学习和生活状态.本文着重研究就业压力对大学生主观幸福感的影响,力图通过社会和大学生双方的共同努力,减缓就业压力,提升大学生的主观幸福感.     

基层法院的执行生态与非均衡执行

执行生态是指法院执行活动所处的环境和氛围,主要包括组织纵向生态、横向生态组成的法院内生态,以及政治生态、经济生态和社会生态组成的法院外生态。对基层法院的调研表明,当前执行工作面临的来自法院外生态的压力过大,这些压力包括政治生态的治理压力、经济生态的救济压力和社会生态的互动压力,而法院内部生态也在一定程度上加大了这些压力。执行生态的过重压力催生出法院对非均衡执行策略的需求与偏好,导致法院一方面通过终结本次执行及执行和解来规避压力,另一方面通过周期性启动运动式执行来缓解压力。非均衡执行策略容易诱发执行不规范现象,有损执行权威。要实现“切实解决执行难”的目标,需要改善执行生态,弱化法院对非均衡执行策略的需求,其中的关键是要建构社会场景下的执行权威,实现良性的执行生态与能动的均衡执行的相互促进。     

64式手枪弹弹头损伤程度与射击距离关系的研究

弹头在与射击客体剧烈撞击过程中所产生的损伤特征是推断射击距离的重要依据。本文对64式手枪弹于不同距离射击墙体后弹头的损伤程度进行研究,探索64式手枪弹弹头损伤程度与射击距离的关系。在射击实验中,用64式手枪和发射药装药量分别为总发射药装药量3/6、4/6、5/6、6/6的64式子弹射击墙体,利用测速仪测量子弹的发射速度并换算得到射击距离,通过体视显微镜观察弹头损伤形态,利用游标卡尺测量子弹撞击面直径、弹头长度并计算得出变形系数。结果表明,射击距离为1~12.33m时,弹头变形严重,呈蘑菇状,而披甲呈爆裂状,铅芯暴露范围大,当其增加至45.57~154.17m,弹头仍呈蘑菇状,部分披甲破裂,暴露出铅芯,当其继续增加至131.59~352.14m,弹头变形程度减小,碰撞面呈扁平状,披甲完整,无铅芯暴露,当其达到425.44~915.81m,弹头变形程度小,碰撞面呈锥形,但弹头表面有明显碰撞和刮擦痕迹;弹头变形系数随射击距离变大而减小,且其下降速率随射击距离增大(尤其当射击距离超过300m时)显著减小。因此,在涉及64式手枪弹射击的案件调查中,可根据枪击现场提取的弹头的损伤程度并结合试射实验结果对射击距离进行推断,但该方法一般只适用于较大范围射击距离的推断。     

监狱基层人民警察的职业压力及对策研究

通过问卷对天津监狱等10所监狱共519名警察的职业压力进行调查研究，分析了监狱一线监区警察的职业压力表现形式，压力对身体、心理和工作的影响。研究者认为，解决我国监狱警察的职业压力问题已经到了刻不容缓的地步，解决上述问题可以通过两种途径实现：一是物质激励，建立增加一线警力编制、激励机制向一线监区倾斜的政策；二是精神激励，在中国监狱系统急需建立警察EAP系统（即警察帮助系统），建立警察心理辅导机构，是目前警察帮助系统的工作重点。     

城市女性劳动力就业的思想状况及对策研究

本文通过问卷调查,总结了目前城市女性就业与再就业面临的现实状况,并且对由于这些现实压力所产生的思想特征进行了分析,最后提出了化解城市女性就业中思想压力的相应对策。     

制度压力如何影响地方政府公共服务创新的扩散?——以城市网格化管理为例

论文从组织社会学的新制度理论的视角出发,构建了制度压力及其他地方政府本身特征因素对地方政府公共服务创新扩散影响的模型。通过对城市网格化管理创新扩散及其影响因素的事件史分析,分别揭示强制压力、同行压力和其他政府自身特征因素对地方政府公共服务创新扩散的影响。实证分析表明,制度压力是影响地方政府创新的重要因素,强制压力和同行压力与城市网格化管理创新的扩散正相关,而城市辖区面积的大小和城市行政层级的高低与城市网格化管理创新的扩散负相关,城市经济发展水平与城市网格化管理创新的扩散正相关。上述研究发现对进一步认识和理解我国地方政府公共服务创新扩散的模式具有重要的现实意义,并可为我国培育和推广卓越的地方政府公共服务创新提供理论依据。     

运用科学发展观创新安全生产工作

用科学发展观理论指导安全生产工作，对各级、各部门、各单位来说，重要的是用这一创新理论提高辩证思维能力、创新安全生产工作。只有这样，才能真正做到理论联系实际，学以致用、用有所成，在安全生产工作中取得新的成效。     

Estimation of explosive charge mass used for explosions on concrete surface for the forensic purpose

The method of choice used by most terrorists for achieving political goals remains the utilization of explosive devices and there is always visible evidence at a crime scene after the deployment of such devices. Given favorable circumstances, forensic analysis can determine the cause of the explosion — the type of the explosive device, the means of detonation, the type and mass of the explosive charge that has been used and perhaps provide information to lead to the identity of the individual who may have constructed or deployed the explosive device, etc. Evidence of an explosion may take the form of a crater or other damage which may provide some information facilitating and estimating the mass of explosive material used. This paper reports the findings obtained by performing experimental explosions of known charges on a concrete surface, in order to establish the correlation between the charge weight and the effects of the explosion. Known masses of explosives were fired and the dimensions of craters made by explosions were measured. Five empirical equations for estimation of the explosive charge mass from crater dimensions were used.     

Quantified Explosives Transfer on Surfaces for the Evaluation of Trace Detection Equipment

Trace explosive test surfaces are often required for the evaluation of trace detection equipment to determine the equipment performance. Test surfaces of C‐4, Detasheet, Semtex‐H, TNT, and HMTD were prepared by transferring trace amount of explosive deposited on polytetrafluoroethylene (PTFE) transfer strips onto different surfaces (Kraft paper, hard plastic, woven fabric, and soft vinyl). The amount of explosive transferred was deduced from the amount of explosive remaining on the PTFE strips after transfer, as quantified by direct analysis using tandem mass spectrometry with thermal desorption. From the data set of over 2000 transfers, we experienced lower transfer efficiency for Semtex‐H and Detasheet, and for soft vinyl and hard plastic. However, the rapid quantification mass spectrometric method allowed the transfer efficiency to be determined for all test surfaces used in an evaluation of trace explosive detectors, thereby permitting only the test surfaces with desired transfer to be accepted for the assessment.     

Evaluation of vapor profiles of explosives over time using ATASS (Automated Training Aid Simulation using SPME)

Despite numerous instrumental achievements, canines are still considered the most effective field method for explosive detection. However, due to strict explosive regulations and safety requirements, it can be a challenge for agencies with "bomb dogs" to train using neat explosive materials. This establishes a need for non-explosive canine training aids with the same volatile component profiles as the explosives that they represent. In order to compare mimic materials to their explosive counterparts, a technique must be established that not only allows for identification of volatile compounds but also can monitor changes in the headspace profile over time with respect to time and temperature. The Automated Training Aid Simulation using SPME (or ATASS) was developed for that purpose. As described, ATASS was used to observe changes in the volatile profile of three explosives (Composition C-4, 2,4-dinitrotoluene (DNT), and triacetone triperoxide (TATP)) and respective prototype training materials (0.1% by mass C-4, 1% by mass 2,4-DNT, and 1% by mass TATP). Samples were prepared in vials and metal tins within a gallon (≈ 3785 mL) paint can to simulate common field techniques for canine training. Monitoring these materials in real time provides a better understanding of the major volatile components present and how the relative abundances of these components can change over time. The results presented indicate that ATASS successfully allows for a sufficient comparison between explosive and non-explosive training materials.     

Particle characteristics of trace high explosives: RDX and PETN

The sizes of explosives particles in fingerprint residues produced from C-4 and Semtex-1A were investigated with respect to a fragmentation model. Particles produced by crushing crystals of RDX and PETN were sized by using scanning electron microscopy, combined with image analysis, and polarized light microscopy was used for imaging and identifying explosive particles in fingerprint residues. Crystals of RDX and PETN fragment in a manner that concentrates mass in the largest particles of the population, which is common for a fragmentation process. Based on the fingerprints studied, the particle size to target for improving mass detection in fingerprint residues by ion mobility spectrometry (IMS) is > or = 10 microm in diameter. Although particles smaller than 10 microm in diameter have a higher frequency, they constitute < 20% of the total mass. Efforts to improve collection efficiency of explosives particles for detection by IMS, or other techniques, must take into consideration that the mass may be concentrated in a relatively few particles that may not be homogeneously distributed over the fingerprint area. These results are based on plastic-bonded explosives such as C-4 that contain relatively large crystals of explosive, where fragmentation is the main process leading to the presence of particles in the fingerprint residues.     

Linking ammonium nitrate-aluminum (AN-AL) post-blast residues to pre-blast explosive materials using isotope ratio and trace elemental analysis for source attribution

Forensic science practitioners are often called upon to attribute crimes using trace evidence, such as explosive remnants, with the ultimate goal of associating a crime with a suspect or suspects in order to prevent further attacks. The explosive charge is an attractive component for attribution in crimes involving explosives as there are limited pathways for acquisition. However, there is currently no capability to link an explosive charge to its source via post-blast trace residues using isotope ratios or trace elements. Here, we sought to determine if pre-blast attribution signatures are preserved after detonation and can be subsequently recovered and detected. A field study was conducted to recover samples of post-blast explosives from controlled detonations of ammonium nitrate-aluminum (AN-Al), which were then analyzed via isotope ratio mass spectrometry (IRMS) and inductively coupled plasma-mass spectrometry (ICP-MS) for quantitation and profiling of isotopes ratio and trace element signatures, respectively. Oxygen and nitrogen isotope ratios from AN-Al yielded some of the most promising results with considerable overlap within one standard deviation of the reference between the spreads of pre- and post-blast data. Trace element results from AN-Al support the findings in the isotope ratio data, with 26 elements detected in both pre- and post-blast samples, and several elements including B, Cd, Cr, Ni, Sn, V, and Zn showing considerable overlap. These preliminary results provide a proof-of-concept for the development of forensic examinations that can attribute signatures from post-blast debris to signatures in pre-blast explosive materials for use in future investigations.     

Application of LC−QTOF/MS for the validation and determination of organic explosive residues on Ionscan® swabs

The identification and confirmation of trace explosive residues along with potential precursors and degradation products require a comprehensive laboratory analysis procedure. This study presents the determination of organic explosives consisting of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), 2,4,6-trinitrotoluene (TNT), 2,4,6,N-tetranitro-N-methylaniline (Tetryl), 1,3,5-trinitrobenzene (1,3,5-TNB) and pentaerythritol tetranitrate (PETN) by a high-resolution liquid chromatography quadrupole time-of-flight mass spectrometry (LC−QTOF/MS). The qualitative information including retention time, collision energy, precursor ions, and characteristic fragmentation pattern of each explosive were collected using an atmospheric pressure chemical ionization (APCI) in negative ion mode. The separation efficiency among five compounds was greatly achieved in this study. Four real explosive samples consisting of TNT, RDX, PETN and Tetryl and 12 Ionscan® quality control swabs from the Royal Thai Army were also tested to validate and verify the viability of the GC–MS method used to validate results from an Ionscan® system. The results showed that LC−QTOF/MS is a powerful technique for the identification and confirmation of thermally unstable organic explosives on Ionscan® swabs compared to a conventional GC−MS technique.     

LC-ESI-MS/MS法分析爆炸尘土中的硝化甘油

目的建立了高效液相色谱-质谱/质谱法（LC-ESI-MS/MS）测定尘土中的硝化甘油（NG）的方法,为日后测定爆炸残留物中的NG奠定基础。方法采用液液提取的方式提取样品,考察了前处理条件、色谱条件及质谱参数,最终确定实验方法。结果选择了最佳液相色谱质谱分析方法：固定相为SB C18（4.6×150 mm,5μm）,甲醇—0.05 mmol氯化铵做流动相,甲醇作提取溶剂;该方法在0.25～10 ng/g范围内呈良好线性,相关系数为0.9990;定量下限为0.25 ng/g;加标回收率为90.4%～95.2%。结论本方法操作简单,提取方便,有效避免了尘土复杂基质的干扰,结果准确可靠,灵敏度高,满足对爆炸残留物中硝化甘油的检测要求。     

Optimizing Accu Time‐of‐Flight/Direct Analysis in Real Time for Explosive Residue Analysis

The use of a direct analysis in real time (DART) mass spectrometer (MS) instrument was optimized for 22 compounds of organic explosive residues to provide a guide for DART‐MS users in rapid screening of explosive compounds. Samples were introduced as neat solutions and sequential dilutions to determine optimal instrument conditions and lowest concentration detectable. Most compounds were optimized to 250°C in the negative ion mode, and several compounds benefited from the addition of a chloride dopant from methylene chloride (amino‐dinitrotoluenes, RDX, EGDN, and PETN). Few compounds were more sensitive in the positive ion mode (TEGDN, DEGDN, HNS, and DMNB). Mixtures of compounds were detected using clean room wipes, directly from their surfaces and from subsequent extractions. Compounds from the mixtures were also successfully detected in soil and from swipes of spiked surfaces. The instrument showed merit in detection of pg/μL solutions for most of the compounds and among the substrates tested.