基于短波紫外光荧光现象快速鉴别静电复印纸的种类

目的 建立无损、快速静电复印纸的鉴别方法.方法 利用文检仪短波紫外光,对30种不同品牌或相同品牌不同批次的静电复印纸测试并比对分析.结果 相同条件下,不同纸张的紫外荧光现象不同,根据纸张在短波紫外光激发下的荧光强弱、荧光纤维条的长短、粗细、弯曲形状和分布稀疏程度等特征,可鉴别不同品牌或相同品牌不同批次的静电复印纸.结论 该方法是一种简单、无损、高效、实用的检验方法.     

利用傅立叶变换红外光谱技术快速检验静电复印纸

目的建立一种利用傅立叶变换红外光谱技术快速检验静电复印纸的新方法。方法采用傅立叶红外光谱仪对近似静电复印纸进行了快速检验,同时分析了新方法的技术特点。结果采用本文所述的方法可以对近似静电复印纸进行准确的快速检验。结论利用红外光谱技术检验纸张是一种较新颖的,快速、灵敏、准确的纸张检测技术,能对纸张的品牌种类,甚至批次进行鉴别,对大量样本鉴别和碎小纸片鉴别尤其适用。     

扫描电镜/能谱法检验激光打印文件

目的 应用扫描电镜/能谱法检验不同品牌和型号激光打印机的打印文件,实现对不同机型打印文件的区分。方法 收集不同品牌和型号激光打印机10台,利用扫描电镜/能谱仪对相同的打印字符进行无机元素分析,获得样品的能谱图和mapping分析图,对样品进行定量和半定性分析;同时收集10个不同品牌的A4静电复印纸,分析纸张对实验结果的影响。结果 依据所含元素的种类可以将10台激光打印机分为四类;依据主要元素相对百分含量的比值,对不同品牌和型号激光打印文件进行区分;研究结果表明纸张因素对定性结果影响较小,对定量结果影响较大。结论 扫描电镜/能谱法可以简单、快速、无损的区分和识别激光打印文件,可以应用于二次打印文件的检验,为侦查破案提供线索。     

烧毁复印纸的提取、显现方法研究

目的建立科学的提取、显现烧毁复印纸的方法。方法制备烧毁复印纸,对比喷雾法、气熏法、涂刷法、水漂法、发胶喷雾法对烧毁复印纸的摊平软化效果;对比夹板固定法和胶带粘取法对烧毁复印纸的固定效果;对比光学检验法、化学显现法对烧毁复印纸文件的显现效果。结果喷雾法摊平软化效果整体上优于其他方法;夹板固定法可适用于大多数烧毁复印纸文件,胶带粘取法适用于打印类复印纸文件;光学检验可以显现出黑笔、蓝笔、红笔、2B铅笔字迹以及指印,化学显现可以更清晰地显现出黑笔、2B铅笔字迹。结论当烧毁复印纸烧毁程度不明确时,摊平软化可选用喷雾法;当烧毁复印纸内容需进一步检验时,固定优选用夹板固定法;显现烧毁复印纸应根据不同显现客体采取合适的方法。     

傅立叶变换红外光谱法检验静电复印墨粉

目的　通过对静电复印墨粉进行检验 ,达到对不同厂家及不同型号墨粉区分的目的。方法　首先利用电熨斗加热提取复印件的墨粉 ,然后利用傅立叶变换红外光谱法对 9个墨粉厂家和 2 4种牌号进行检验。结果可以达到厂家区分和大部分牌号区分 ,区分率达到 95 .7%。结论　本研究对实际应用有较大参考价值。     

拉曼光谱法鉴别常见毒品

目的建立一种识别毒品与其它常见白色物质的方法。方法使用激光显微拉曼光谱法对7种毒品和5种白色粉末进行了分析。结果7种常见毒品均有丰富的拉曼位移峰,可以通过其位移峰峰位的不同区分不同成分的毒品。另外,通过拉曼位移峰的峰位,还可以将7种常见毒品与5种常见白色粉末区分开来。结论拉曼光谱法适用于快速准确地识别毒品。     

拉曼光谱法鉴别常见炸药

目的建立一种识别炸药的方法。方法使用激光显微拉曼光谱法对17种常见炸药粉末进行了分析。结果17种常见炸药均有丰富的拉曼位移峰,可以通过其位移峰峰位的不同区分不同成分的炸药。结论拉曼光谱法适用于快速准确地识别炸药。     

表面增强拉曼光谱对黑色圆珠笔快速鉴别的检测研究

目的 建立圆珠笔油墨的表面增强拉曼光谱分析方法,实现更加有效的圆珠笔样品种类区分。方法 选用纳米银胶体作为增强试剂,在785、633、514 nm 3种激发光波长下,分析检测市场上55支黑色圆珠笔的表面增强拉曼光谱,并通过将各激发光波长下的数据相结合来综合分析种类区分信息。结果 根据表面增强拉曼光谱图可有效区分出不同品牌圆珠笔油墨之间的差异。与增强前的拉曼光谱相比,增强之后的谱峰信号更强,在进行种类区分时更具说服力。785、633、514 nm 3种激发光波长的谱图信息相结合可获取更多有效的区分信息。结论 该方法能够有效鉴别不同品牌同一颜色的圆珠笔油墨,为司法鉴定中油墨成分的快速鉴别提供新思路。     

长时共振峰分布特征在声纹鉴定中的应用

目的利用长时共振峰分布特征区分不同发音人。方法以汉语普通话为语料,对20位男性发音人和20位女性发音人的前四条共振峰的长时分布情况进行了统计比较分析。结果发现各长时共振峰分布的均值、中位数、众数、峰数、峰度和斜度等参数能够反映出不同发音人的个性特征,稳定性较强。前四条长时共振峰的分布结构比较均匀,由此推测在语料足够长的情况下,所有元音平均后的结果应该是一个类似央元音的＂音＂。结论利用长时共振峰分布特征可以较好地区分不同发音人。     

黑色墨迹的拉曼光谱分析

目的对常见的黑色墨迹进行初步筛选,为墨迹的进一步检验提供依据。方法依据黑色墨迹的同色异谱特征,利用显微共焦激光拉曼光谱仪对19种黑色墨迹进行分析检验。结果根据不同墨迹的拉曼谱图,19种黑色墨迹可以分为3大类,即:未检出拉曼峰的墨迹,只检出碳物质的墨迹,以及主体色料为染料的墨迹。结论拉曼光谱可用于区分不同种类黑色墨迹,从而为选择合适的方法对黑色墨迹进一步进行检验奠定基础。     

苯酚-硫酸分光光度法检验复印纸的研究

本文建立了苯酚-硫酸分光光度法测定复印纸水解液中还原糖含量鉴别复印纸的方法。还原糖与浓硫酸在一定条件下反应生成的产物可与苯酚反应生成有色物质,当检测波长为490nm,线性范围为0．02～0．14mg／ml,葡萄糖含量与吸光度的线性关系为Y=6．9425C＋0．0284,相关系数r=0．9997,平均加标回收率为99．29／6,相对标准偏差为0．46％。该方法具有简单、快速和灵敏度高等优点,为纸张的种类鉴别提供了一种实用的方法。     

Fluorescence spectra and images of latent fingerprints excited with a tunable laser in the ultraviolet region

Fluorescence spectra of sebum-rich latent fingerprints were studied with a tunable laser for non-destructive fingerprint detection without chemical treatment. The tunable laser consists of a nanosecond pulsed Nd-YAG laser and an optical parametric oscillator (OPO) crystal. The fluorescence spectra and images were measured at various excitation wavelengths in the ultraviolet region by the time-resolved fluorescence method. We have previously reported that a typical fluorescence spectrum of fingerprints consists of two peaks located at c. 330 and 440 nm. In order to determine the wavelength of optimal excitation, excitation spectra were measured at wavelengths ranging from 220 to 310 nm. The fluorescence intensity of the 330 nm peak became maximal with excitation at 280 nm. The images of latent fingerprints on white papers were also measured and the clearest image was obtained with excitation at 280 nm. The influence of continuous irradiation on the fluorescence of fingerprints was measured at the optimal excitation wavelengths. The 330 nm peak was strong at first and decreased with continuous irradiation, whereas the 440 nm peak, which was weak at first, increased gradually.     

A comparison of the characteristics of profiles produced with the AMPFlSTR SGM Plus multiplex system for both standard and low copy number (LCN) STR DNA analysis.

DNA STR profiles have been generated from 1 ng and low copy number (LCN) templates using 28 and 34 cycles of amplification, respectively. Characteristics which facilitate the interpretation of profiles, such as heterozygous balance, allelic dropout and stutter proportions have been quantified. We demonstrate that a reduction in DNA template coupled with an increase in amplification cycle number produces an increased rate of allelic dropout out which can be correlated to the peak areas of those alleles observed. In addition, the LCN conditions increase the degree of peak area asymmetry observed from heterozygotes and the size range of stutters. Analysis of the data allows us to develop sets of guidelines appropriate for interpreting both single and mixed DNA profiles.     

North American transnational youth gangs: Breaking the chain of violence

Youth gangs are nothing new. They appeared in New York City and Philadelphia at the end of the American Revolution. Their numbers and violence correspond to peak levels of immigration and population shifts that occurred in the early 1800s, 1920s, 1960s, and late 1990s. Entrenched in American culture, gangs are romanticized in movies while rap artists copy their dress and jargon. However, because of their growing membership and globalization, gangs have become a public security threat that must be addressed.     

A stochastic model of the processes in PCR based amplification of STR DNA in forensic applications

In forensic DNA profiling use is made of the well-known technique of PCR. When the amount of DNA is high, generally unambiguous profiles can be obtained, but for low copy number DNA stochastic effects can play a major role. In order to shed light on these stochastic effects, we present a simple model for the amplification process. According to the model, three possible things can happen to an individual single DNA strand in each complete cycle: successful amplification, no amplification, or amplification with the introduction of stutter. The model is developed in mathematical terms using a recursive approach: given the numbers of chains at a given cycle, the numbers in the next can be described using a multinomial probability distribution. A full set of recursive relations is derived for the expectations and (co)variances of the number of amplicon chains with no, 1 or 2 stutters. The exact mathematical solutions of this set are given, revealing the development of the expectations and (co)variances as function of the cycle number. The equations reveal that the expected number of amplicon chains without stutter grows exponentially with the cycle number, but for the chains with stutter the relation is more complex. The relative standard deviation on the numbers of chains (coefficient of variation) is inversely proportional to the square root of the expected number of DNA strands entering the amplification. As such, for high copy number DNA the stochastic effects can be ignored, but they play an important role at low concentrations. For the allelic peak, the coefficient of variation rapidly stabilizes after a few cycles, but for the chains with stutter the decrease is more slowly. Further, the ratio of the expected intensity of the stutter peak over that of the allelic peak increases linearly with the number of cycles. Stochastic models, like the one developed in the current paper, can be important in further developing interpretation rules in a Bayesian context.     

The transfer of public science to patented technology: A case study in agricultural science

One of the most difficult challenges in technology transfer is to measure the movement of knowledge from basic scientific research to industrial technology. This paper will report on a study of the linkage between science supported by the Agricultural Research Service (ARS) and patented technology. This study traced the citations from U.S. patents issued in 1987–88 and 1993–94 to scientific research papers linked to the U.S. Department of Agriculture (USDA). The number of patent citations to ARS papers, and to other USDA-supported papers has increased fourfold over the six-year period. A distinct difference also exists between the patent-cited ARS papers and patent-cited extramural USDA-supported papers: ARS papers are in more agriculturally related journals, while the extramural papers were in more basic and biomedical journals. USDA-supported papers were overwhelmingly cited by U.S.-invented patents (in a patent system in which half the patents are foreign-invented). In the primary field of ARS papers (Biology), they are cited much more often by patents than Biology papers from any other publishing organization. Since the publishing organizations and support sources of all the papers cited in these patents have now been identified, we can study the transfer of scientific results to patented technology by institution, by agency, or by any other category of patent or paper holder. The authors thank the Agricultural Research Service of the U.S. Department of Agricultural, especially Dr. Richard Parry, for this paper' use of the study performed for them by CHI Research, Inc. (Grant number 59-0790-6-054)     

著作权法中的复制权研究

复制权是著作财产权的基础和核心,但复制的内涵却随着技术的发展而日趋扩张,从单纯的印刷复制到模拟复制再到数字复制,复制在技术面前迷失了本质。由于各国关于复制权的理论基础与立法结构不同,复制内涵的发掘更是莫衷一是。从激励理论看,复制是对作品形式的再现,是著作权人控制作品市场利益的手段之一,集中反映了复制件的非独创性与竞争性特点。认识这一特点对解决异形复制、自发复制和暂时复制等新型复制方式具有非常重要的意义。从非独创性与竞争性二维视角来看,新型复制方式产生的利益应该在竞争市场上以复制与创作为边界进行分配,从而在激励著作权人的前提条件下实现著作权人独占利益与公众利益的动态平衡,保证公众接近作品和著作权人行使独占权在著作权法中各得其所。     

Thermal development of latent fingermarks on porous surfaces—Further observations and refinements

In a further study of the thermal development of fingermarks on paper and similar surfaces, it is demonstrated that direct contact heating of the substrate using coated or ceramic surfaces at temperatures in excess of 230 °C produces results superior to those obtained using hot air. Fingermarks can also be developed in this way on other cellulose-based substrates such as wood and cotton fabric, though ridge detail is difficult to obtain in the latter case. Fluorescence spectroscopy indicates that the phenomena observed during the thermal development of fingermarks can be reproduced simply by heating untreated white copy paper or filter paper, or these papers treated with solutions of sodium chloride or alanine. There is no evidence to suggest that the observed fluorescence of fingermarks heated on paper is due to a reaction of fingermark constituents on or with the paper. Instead, we maintain that the ridge contrast observed first as fluorescence, and later as brown charring, is simply an acceleration of the thermal degradation of the paper. Thermal degradation of cellulose, a major constituent of paper and wood, is known to give rise to a fluorescent product if sufficient oxygen is available [1], [2], [3], [4], [5]. However, the absence of atmospheric oxygen has only a slight effect on the thermal development of fingermarks, indicating that there is sufficient oxygen already present in paper to allow the formation of the fluorescent and charred products. In a depletion study comparing thermal development of fingermarks on paper with development using ninhydrin, the thermal technique was found to be as sensitive as ninhydrin for six out of seven donors. When thermal development was used in sequence with ninhydrin and DFO, it was found that only fingermarks that had been developed to the fluorescent stage (a few seconds of heating) could subsequently be developed with the other reagents. In the reverse sequence, no useful further development was noted for fingermarks that were treated thermally after having been developed with ninhydrin or DFO. Aged fingermarks, including marks from 1-year-old university examination papers were successfully developed using the thermal technique.