茚二酮、1,8-二氮杂-9-芴酮和茚三酮在手印序列显现中的应用

为了提高纸张上汗潜手印的显出率,选用茚三酮、1,8-二氮杂-9-芴酮(DFO)和茚二酮3种氨基酸检测试剂,对复印纸上连续按捺5次的手印进行序列显现,探究这3种试剂联合使用时显出率较高的序列。研究结果表明单独使用1种试剂时灵敏度排序是茚二酮>DFO>茚三酮;2种试剂联用序列显出率高的是DFO→茚三酮和茚二酮→DFO;3种试剂联用序列显出率最高的是茚二酮→DFO→茚三酮。因此,在进行手印序列显现时,先使用茚二酮,再用DFO,最后用茚三酮能达到最佳显现效果。     

湿度对ESDA处理和指纹信息显现的影响

在法庭科学领域 ,ESDA处理的湿度影响和随后纸张上指纹信息的显现 ,正在进行广泛的研究。如果用DFO显现预先湿润的纸张上的指纹 ,指纹的质量几乎不受影响 ,而用茚三酮和茚满二酮显现湿润纸张上的指纹 ,其质量差异非常明显。     

乙醇为承载液时DFO指纹显现液的性能及应用

以乙醇替代CFC-113或HFE-7100作为承载液,考察了1,8-二氮芴-9-酮（1,8-Diaza-fluorene-9-one,DFO）对常用纸张和墨迹上指纹的显现性能。结果表明：乙醇为承载液时,DFO对常用纸张上指纹的显现效果无明显差异;除油性圆珠笔墨迹外,常用的中性签字笔墨迹、碳素墨迹、蓝黑墨迹、纯蓝墨迹、激光打（复）印件墨迹和报纸墨迹均不影响指纹显现。     

潮湿纸张类客体上潜在手印的显现方法研究进展

纸张类是犯罪现场常见客体之一,对于纸张类客体上遗留的潜在手印,常采用茚三酮、DFO、茚二酮等常见的氨基酸指示剂进行显现。但犯罪现场环境复杂,若遗留有潜在手印的纸张已浸湿或长期处于潮湿环境中,那么手印遗留物中的水溶性成分会部分或全部溶解于水中,从而限制了上述方法的使用。因此,对于潮湿纸张类客体上潜在手印的显现,一直都是研究的难点与重点。旨在对潮湿纸张类客体上潜在手印的显现方法进行综述,以便于开展后续研究。     

硝酸银、茚三酮与DFO对常见纸张上新鲜手印显现对比研究

利用硝酸银、茚三酮与DFO这三种化学显现手印的方法,对比探索一下对常见纸张上汗潜手印哪种显现方法更灵敏,显现的质量更好。避免选用错误的显现方法,导致检材上的手印显现质量不高,或者导致检材损坏,不能进行复检。所以需要探索一下这三种方法哪种方法对于常见纸张上新鲜汗液手印的显现更好,有利于公安基层一线更好的使用。     

混合显现液对纸张客体潜在手印显现效果的探究

通过初步实验筛选出0.5%硝酸银乙醇溶液与1%茚三酮乙醇溶液对渗透性客体显现效果最佳,然后配置茚三酮、硝酸银乙醇混合液对牛皮纸、白纸、报纸三种客体表面上遗留的新鲜和陈旧汗潜指印进行显现。结果表明硝酸银、茚三酮乙醇混合显现液能显现纸张等渗透性客体上的新陈汗潜手印,且与单个试剂显现效果比较,混合显现液显现效果优于单个试剂的显现效果。     

热敏纸上汗潜手印使用传统方法显现的改良研究

热敏纸上汗潜手印的显现一直是一个难题,因为热敏纸在使用传统的显现方法处理时会变色,而且其本身在加热条件下或接触到极性溶剂后迅速变黑,从而严重干扰了手印的正常显现。通过加入石油醚系统地稀释茚三酮、茚二酮和DFO的原溶液,根据不同稀释比的显现效果选出最佳的稀释比例。实验表明,茚三酮与茚二酮的最佳稀释比分别为1∶1和1∶2,而DFO则不适宜用来显现热敏纸上的汗潜手印。     

茚三酮和指甲花醌显现纸张上汗潜手印比较研究

基于"绿色化学"理念,为了评估天然植物提取物质指甲花醌显现纸张上汗潜手印的能力,将其与茚三酮显现纸张上汗潜手印的能力进行比较。采用茚三酮和指甲花醌分别对复印纸、热敏纸、胶版纸3种纸张上遗留时间分别为1、5和10 d的汗潜手印样本进行显现,从显现原理、适用范围、试剂配方、操作流程、显现效果、经济性、安全性等角度对这两种方法的显现能力进行综合分析,结果发现二者显现原理、适用范围相似,但指甲花醌方法与茚三酮方法相比具有溶液配制简单、经济成本低、显现能力强、安全性高、绿色环保等优势。     

使用硝酸银和LED区分A4纸上的新旧指纹

使用含水5%的硝酸银乙醇溶液,选用合适的LED光源,严格控制光强,在A4纸上进行的指纹显现实验结果表明:不论是人工指纹还是自然指纹,淡的新指纹(4~6小时)总是在浓的旧指纹(3天)之前出现,即该方法可以作为"新旧指纹差异化显现技术"中的一种,有望为解决一些复杂案件提供技术支持。同时使用了传统的茚三酮方法进行实验,结果表明:茚三酮虽然不能区分新旧指纹,但是可以用于指纹续显。     

凝胶型DFO指纹显现剂的制备及应用

使用溶胶-凝胶法将常用的指纹显现剂DFO制成凝胶,根据其溶剂挥发慢、扩散难以及立面不流淌的特性,将其试用于打印纸、人民币等渗透性的样品,效果与溶液法相当;在抽屉、门等非渗透性垂直表面,凝胶法的指纹显现效果明显优于传统DFO溶液。     

Electrochromic property of nano-composite Prussian Blue based thin film

In this paper, we present fabrication of a nano-composite Prussian Blue (NPB) film to synchronously improve the contrast and switching time of regular Prussian Blue (PB) film by applying the concept of nano-technology. The NPB consists of indium tin oxide (ITO) nano-particles (3.0 ± 1.0 Ω, 40 ± 5 nm) as a medium layer for PB to gain larger operative reaction surface area in Li⁺ based electrolyte (1 M LiClO₄/PC) system. The procedures for preparation of NPB are: first, a well-dispersed ITO nano-particle solution is sprayed onto ITO glass (30 Ω/sq) at 200 °C; the PB film is then electroplated onto the pre-sprayed ITO nano-particles. Since ITO nano-particles can be well covered with PB, the NPB film forms a nano-porous electrochromic layer. The switching speed and contrast of NPB exhibit much better performances than traditional PB thin films. The structure, morphology, and electrochromic properties were characterized by scanning electron microscopy (SEM), cyclic voltammograms (CV), and UV-vis spectroscopy.     

A diffusion‐reaction model for α‐chymotrypsin carrying uniform thermosensitive gel beads

In this study, the kinetic behavior of α‐chymotrypsin‐immobilized, uniform poly(isopropylacrylamide) gel beads was investigated. The kinetic study was performed by using a continuous reactor operated at steady‐state conditions. In the experiments, substrate feed concentration, residence time, and reactor temperature were changed. The results were explained by a diffusion–reaction model developed for steady‐state conditions. The effectiveness factor and Thiele modulus values of the thermosensitive enzyme–gel system were estimated at different temperatures by using an iterative procedure based on fourth order Runge–Kutta algorithm. The results indicated that the overall hydrolysis rate was controlled by the substrate diffusion through the gel matrix. A bending point was detected for the Thiele modulus at the lower critical solution temperature (LCST) of the thermosensitive gel. The effective diffusion coefficient of substrate and effectiveness factor decreased suddenly at LCST. The mass transfer process within the thermosensitive carrier could be described in detail by the proposed model. The results of our numerical procedure were also compared with an analytical approximate solution available in the literature. The consistency between two different model was reasonably good. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1025–1034, 1999     

Systematic study of dye loaded small mesoporous silica nanoparticles for detecting latent fingerprints on various substrates

Uniform mesoporous silica nanoparticles (MSNs) with small particle size of ca. 50 nm were fabricated and used as a novel developing agent for latent fingerprints detection. Methylene blue (MB) molecules as a representative dye were loaded in the mesopore of MSNs in order to increase the contrast of the developed latent fingerprints. Both powder and suspension methods composed of MSNs and MSNs@MB were investigated on various substrates, and both of them were able to realize the latent fingerprints development. Moreover, powder method can successfully achieve the detection of the sweat pores (i.e., the typical feature of tertiary structure) of the latent fingerprint, and it has a better effect (i.e., contrast, selectivity and resolution) of latent fingerprints development than suspension methods. In addition, trimethylsilyl (TMS) groups were grafted on the surface of MSNs to increase the hydrophobic nature of particles, but MSNs-TMS@MB had the worse effect of latent fingerprint development than MSNs@MB.     

茚三酮比色法测定水中微量氨含量

在一定酸度和温度条件下,氨能与茚三酮和还原性茚三酮反应生成蓝紫色化合物.依据此原理,通过系列条件试验,确定了显色剂、还原剂、缓冲液的加入量和显色时间,建立了不使用剧毒试剂(氯化高汞)测定水中微量氨含量的比色分析法.通过标准曲线试验、精密度试验、回收率试验和对比试验,验证了该测定方法准确、可靠.     

Numerical simulation of localized cure of thermosensitive resin during thermo stereolithography process (TSTL)

In this work, to analyze a type of rapid prototyping technique, a numerical model was developed that was able to simulate the heat transfer at thermosensitive polymeric material during cure by laser irradiation. The analysis was carried out as a transient thermal problem using the general‐purpose finite element software ANSYS. The technique analyzed was thermal stereolithography, which uses a CO₂ laser beam to cure (solidify) thermosensitive liquid resins in a selective way to produce three‐dimensional parts. In this numerical analysis, the temperature distribution at thermoset material heated by a laser irradiation and its thermal properties are investigated. This resin is a high‐viscosity sample composed of epoxy resin, diethylenetriamine, and silica powder, which become highly crosslinked when irradiated by infrared laser. The localized curing becomes critical when the amount of silica and laser parameters are not appropriate. Bearing this in mind, this work intends, by applying the numerical method developed, to analyze the thermal behavior of resins in function of amount of silica and the laser radiation conditions, so that it is possible to have a knowledge on these variables so as to achieve a product with the required specifications. © 2006 Wiley Periodicals, Inc. J Appl PolymSci 102: 2777–2783, 2006     

Fluorescent polymer nanofibers based on polycaprolactone and dansyl derivatives for development of latent fingerprints

This work provides a convenient low-cost strategy for fast fabrication of dansyl-based fluorescent nanofibers for development of latent fingerprints aiming forensic applications. Polycaprolactone (PCL) and dansyl cadaverine (DnsCad) or dansylglycine (DnsGly) nanofibers are prepared by electrospinning technique and characterized by SEM, FTIR, thermal analysis, and fluorescence spectroscopy. The electrospun PCL/DnsCad and PCL/DnsGly nanofibers are fluorescent with greenish blue and yellowish green emission, respectively. Such nanofibers are useful for enhancement of the visual contrast of latent fingerprints on metallic surfaces when exposed to UV light. These findings are particularly important for development of latent fingerprints on cartridge cases.     

热分析数据系统的开发及应用研究

研究开发出一套可用于改造老式热分析仪的数据处理系统。该系统适用于早期进口的各外国公司和国产的不同型号的DSC、TG、DTA和TMA等仪器 ;可在Windows　 95 / 98下运行 ;不但可以有效地提高各种老式仪器的工作效率 ,还可以对实验数据进行各种处理 ,并把结果 (曲线 )以图片方式直接剪贴到用words软件处理的文字文件中