图像处理技术在物证照片标准化制作中的应用

根据《刑事照相制卷质量标准》对物证照片的要求，以Photoshop 7．0图像处理软件为工具，通过对物证照片放大倍数的调整、照片尺寸的设定和打印输出的设置等操作步骤和方法的介绍，说明图像处理技术在物证照片标准化制作中的应用，并指出在物证照片的拍照、图像处理和打印输出过程中应该注意的问题。     

常用滤色镜在物证照相中的应用实验研究

常用滤色镜是一种能按照规定需要改变入射光光谱成分分布的光学器件,其运用可以满足任意波段色光的物证照相的需要。在物证照相中最常采用的是用滤色镜来进行分色照相。立足于常用滤色镜在物证照相中研究本体,首先概述常用滤色镜基本理论,继而分析常用滤色镜在物证照相中的应用,最后通过常用滤色镜在物证照相中的应用实验表明其作用,以期对相关研究有所借鉴意义。     

电子闪光灯在物证近距摄影中的应用

电子闪光灯具有适合于物证近距摄影的基本要求的光线特点。电子闪光灯运用于物证近距摄影时，可以灵活控制照度强弱及曝光量；通过多种手段控制平均配光；可以用预闪功能或借用手电筒预览照明效果。     

比例照相及对标尺运用的要求

比例照相，是指对所摄痕迹物证加标尺进行拍摄，然后按照一定的比例进行放大制作，最终取得一定比例规格照片的过程。比例照相中的比例，是指照片中痕迹物证的大小、长短与现场实际中痕迹物证的大小、长短之比。比例规格的分子通常为１，分母数字越大，比例越小；字母数字...     

CNAS认可公告

天津市公安局物证鉴定中心（证书号：L4109） 认可范围：生物物证检验（DNA），法医检验、法医损伤检验，痕迹检验，电子物证，文件检验，指纹检验，毒化检验，理化检验，照、录像检验。     

警犬在搜索几种毒物物证中的应用

本文通过对微量物证在法庭科学和司法实践中重要性的分析和研讨，综述了现阶段警犬搜索技术在几种常见微量物证搜索中的应用。     

物证档案管理

物证档案管理同样也是物证保全技术的薄弱环节,本文主要从物证管理与物证档案管理的相关法律规制,物证管理的场所与人员,物证的存取登记制度,物证处理制度等四个方面论述了物证档案管理。     

多向可控物证摄影载物平台的研制及其应用

物证摄影载物平台是物证光学检验的必备设备,由于光学检验需要对物证进行精准的配光,因此对物证摄影的载物平台提出了较高的要求.本文设计并研制了多向可控物证摄影载物平台,该装置可以对物证进行前后、左右、上下、旋转、倾斜等多向调整,既可单向运动又可多向同时运动,为精准配光提供了方便,并在在实际案件中得到了成功的应用.     

数码相机在痕迹物证拍照中的应用

尽管数码科技日新月异的发展,但人们还是普遍认为在犯罪现场痕迹物证的拍照中,数码相机还难以同传统相机的银盐胶片相抗衡.那么,现在市面上所售的中档价位的数码相机能否适应现场物证照相的要求,所摄照片能否保持如传统照片所记录的物证细节呢?带着这个问题,笔者用数码相机进行了犯罪现场中常见痕迹的拍照试验.     

数字成像技术在警方的应用

数字成像技术在警方的应用犯罪调查即对来自犯罪现场的证据分析判断的过程。对指纹、笔迹、作案工具等物证的高效、准确的鉴别，往往是侦察工作成功的关键。传统的侦察方式，特别是指纹及相关物证的提取，已沿用了很长时间，也已为大家熟悉。今天，警察机构侦察方面的影像...     

Wire electrical discharge machining characteristics of AA6061/cenosphere as-cast aluminum matrix composites

Machining of metal matrix composites (MMCs) reinforced with low-density waste byproduct particulates using nonconventional processes is relatively new in the field of material science. However, more attention has been paid for investigations on nontraditional machining of such MMCs currently as the conventional machining may generate additional complexity. This study investigates the wire electro-discharge machining behavior of compo-casted cenosphere-reinforced AA6061 alloys. Cu₆₀Zn₄₀-coated copper wire was used as electrode material. The investigation demonstrates that melting and vaporization are the dominant machining mechanisms. The weight fraction of cenosphere was observed to be the most substantial process variables affecting the cutting rate, on-time, and the wire speed of tool were the next in the order of importance. The presence of nonconductive cenosphere particles along with thermal degradation of the aluminum matrix composites leads to degrading processed machined surface quality. The issues related to wire breakage and poor quality of the machined surface, surface finish, and dimensional accuracy are described in detail.     

多股铜导线过载残留物表面形貌分析

利用火灾痕迹物证综合实验台,制备多股铜导线在不同过载电流作用下的残留物,用数码相机和扫描电子显微镜观察和分析导线的表面形貌。结果表明：随着过载电流的增大,绝缘层逐渐变软、膨胀、起泡、熔化以及炭化,并与芯线脱离;芯线表面氧化程度加重,沟槽状的加工划痕逐渐消失,并出现金属熔化流淌痕迹。因此,利用数码相机和扫描电子显微镜观察和分析多股铜导线表面的形貌特征,可以鉴别其是否过载以及过载的程度。     

Application of ZnO single-crystal wire grown by the thermal evaporation method as a chemical gas sensor for hydrogen sulfide

A zinc oxide single-crystal wire was synthesized for application as a gas-sensing material for hydrogen sulfide, and its gas-sensing properties were investigated in this study. The gas sensor consisted of a ZnO thin film as the buffer layer and a ZnO single-crystal wire. The ZnO thin film was deposited over a patterning silicon substrate with a gold electrode by the CFR method. The ZnO single-crystal wire was synthesized over the ZnO thin film using zinc and activated carbon as the precursor for the thermal evaporation method at 800 degrees C. The electrical properties of the gas sensors that were prepared for the growth of ZnO single-crystal wire varied with the amount of zinc contained in the precursor. The charged current on the gas sensors increased with the increasing amount of zinc in the precursor. It was concluded that the charged current on the gas sensors was related to ZnO single-crystal wire growth on the silicon substrate area between the two electrodes. The charged current on the gas sensor was enhanced when the ZnO single-crystal wire was exposed to a H2S stream. The experimental results obtained in this study confirmed that a ZnO single-crystal wire can be used as a gas sensor for H2S.     

Electrical Discharge Machining of MMCs Reinforced with Very Small Particles

This paper investigates material removal rate (MRR), kerf width, surface finish, and electrode wire wear for different pule-on-times as well as wire tensions during EDM of 6061 aluminum alloy reinforced with 10 vol % 700 nm SiCp MMC. Effects of pulse-on-time on output variables at lower and higher wire tensions were investigated. Similarly, effects of the wire tensions on output variables at shorter and longer pulse-on-times were also investigated. Longer pule-on-time increases the MRR though the higher wire tension reduces the MMR. The effect of wire tension on MRR is much more significant at longer pule-on-time compare to that at shorter pule-on-time. There is an optimum pule-on-time for which best surface finish is achieved. The surface finish deteriorates when the pulse-on-time is higher or lower than the optimum pule-on-time. With the rise of tension in wire, the surface roughness increases and decreases at shorter and longer pule-on-times, respectively. The machined surface contains solidified molten material, splash of materials, and blisters. Generation of the tapered slot with higher kerf width at the top indicates the wear of wire electrode. Significant variation of the electrode wire diameter was due to coating of the matrix, wear, and clogging of small reinforced particles in the electrode gap.     

Wire EDM Mechanism of MMCs with the Variation of Reinforced Particle Size

The size of reinforced particles notably affects the electro-discharge machining (EDM) of metal matrix composites (MMCs). This paper explores the mechanism of wire EDM of MMCs with different sizes of reinforced particles as well as the corresponding unreinforced matrix material. The mechanisms of material removal, surface generation, and taper kerf formation were investigated. This study shows that the particles’ ability to protect matrix materials from the intense heat of electric arc controls the material removal rate, surface generation, and taper of kerf. The low melting point matrix material is removed very easily, but the heat resistance reinforced particles delay the removal of material and facilitate the transfer of the workpiece material to wire electrode and vice versa. Thus, the material stays longer in touch with intense heat and affects the surface generation, wire electrode wear, and width of the kerf.     

绳锯线弓角静态测量方法的研究

金刚石绳锯在切割圆弧板材时,受到进给方向的阻力,形成"线弓角",使板材中部产生"过切",严重时导致材料报废.为解决这一问题,提出了线弓角的概念,从理论上提出了一种基于悬臂式力传感器的绳锯线弓角的静态测量方法,通过轴力传感器输出的电压值计算出线弓角度.试验在自行设计和搭建的绳锯线弓角测量平台上进行,用钢丝绳模拟串珠绳产生线弓角,并进行导轮受力与线弓角关系的静态测量试验分析,以验证该方法测量线弓角的可行性.试验结果表明:在一定范围内,串珠绳初始张紧力越大,线弓角的计算值越接近理论值.因此,采用所提出的测量方法,当装有轴力传感器的导轮处在刚好与钢丝绳接触的状态下,选择合适的初始张紧力,可以测得较准确的角度值.     

Characteristics of wire-electro discharge machined Ti6Al4V surface

Titanium and titanium alloys (e.g., Ti6Al4V) are increasingly used in aerospace and automotive industries, and also used as medical implant material in wide variety of applications. Wire-electro discharge machining (WEDM) is an important non-traditional machining process, widely used for machining a variety of difficult-to-machine materials including titanium alloys with intricate shapes. The process is essentially a thermal process and the nature of surface produced is studied in this paper. It is observed that more uniform surface characteristics are obtained with coated wire electrode. Among the parameters such as time between two pulses, pulse duration, injection pressure, wire speed and wire tension that have more influence on the surface characteristics, the time between two pulses is the most sensitive parameter.     

Output Properties of Zero-Speed Sensors Using FeCoV Wire and NiFe/CoFe Multilayer Thin Film

Output properties of magnetic sensors generating pulse voltages are described. The sensors principally consisted of double magnetic layers with different coercive forces. Both of thin-film-based material and wire-based material were used for the double layers. When the magnetization of one of the layers was switched by an external magnetic field, a pulse voltage was induced in a pickup-coil wound around the materials. The magnetic sensor using a twisted FeCoV wire, the conventional material for the Wiegand effect, had the disadvantage of the asymmetric output voltage generated by the alternative magnetic field. It was found that a magnetic wire, whose ends were slightly etched, exhibited symmetric output voltage. The sensor element consisting of a patterned NiFe/CoFe multilayer thin film was also studied. Constant output voltage was obtained from this thin-film sensor using an excitation magnetic field at frequencies down to 0.1 Hz.     

水平双主动水箱拉丝机主传动系统设计和配模计算

通过对主传动系统的设计计算和拉丝过程中的配模计算,使主传动系统和配模之间有了较好的匹配,较好地解决了钢丝生产过程中钢丝及滑轮间严重磨损造成钢丝破坏等问题,保证了拉丝机的性能和可靠性,提高了钢丝生产的质量和效率。     

Erfahrungen mit hochlegierten Fülldrahtelektroden im Chemieapparatebau

Experience with High Alloy Material in the Construction of Chemical Apparatus Cored wire electrodes are today being used in many sectors for joint welding and surfacing. Their increasing importance is due to their advantages compared with other types of filler material. Here we should mention in particular the economic aspects, such as high fusion efficiency when the semiautomatic MIG/MAG process is used. The exact metering of the alloying constituents as well as the deoxidizing and slag forming additions to filler material enable the intended adjustment in the desired composition of the filler material to be obtained, whilst maintaining a high level of purity.