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911.
目的 对知母(Anemarrhena asphodeloide Bunge.)的干燥须根进行化学成分研究。方法 采用硅胶柱色谱、Sephadex LH-20柱色谱及重结晶等手段进行分离纯化,运用波谱学方法鉴定化合物的结构。结果 从知母须根中分离得到15个化合物,分别鉴定为胡萝卜苷(1)、菝葜皂苷元(2)、芒果苷(3)、7-hydroxy-3-(4-methoxybenzyl)-chroman(4)、3′-hydroxy-4′-methoxy-4-dehydroxynyasol(5)、5, 7-dihydroxy-3-(4-methoxybenzyl)-chroman-4-one(6)、2,4′-dihydroxy-4-methoxy benzophenone(7)、1,3-Bis(4-hydroxyphenyl)pent-4-en-1-one(8)、(+)-syringaresinol(9)、ent-16, 17-dihydroxy-kauran-19-oic acid (10)、(+)-pinoresinol (11)、对羟基苯甲酸(12)、新芒果苷(13)、丁香酸 (14)、4′,6-dihydroxy-4-methoxy- benzophenone-2-O-(2″), 3-C-(1″)-1-desoxy-α-L-fructofuranoside (15)。结论 化合物5~11、14、15为首次从知母须根中分离得到。 相似文献
912.
目的 准确找出白薇与其混伪品老瓜头、紫花合掌消之间存在的差异及其鉴别点。方法 在野外调查和市场调查的基础上,收集和采集药材样品,运用药材性状鉴定、微性状鉴定、显微鉴定等方法对白薇及其伪品的鉴别方法进行研究。结果 白薇及其伪品药材的主要区别在于根粗细均匀,表面有细纵褶皱及点状分泌物,木心颜色淡黄及占横断面的比例较小,表皮下皮层常茎向延长、皮层宽,内皮层类圆以及其内侧石细胞无或偶有出现等。结论 可通过性状鉴别、微性状鉴别、显微鉴别等方法将白薇及其混伪品老瓜头、紫花合掌消区别开。 相似文献
913.
目的 对中药材市场中红花及其掺伪品进行鉴别。方法 采用微性状鉴定法对红花及其掺伪品进行观察鉴别。结果 红花与其伪品、掺伪品存在明显区别,红花花冠颜色和微性状特征可确定是否为正品;花丝与花药颜色及水浸后的花冠颜色可区别是否提取有效成分;红花花冠表面附着物的特征可以区别是否掺杂增加质量,花粉粒颜色为红色即可认定为染色红花。结论 微性状鉴别法可准确区分红花正品与掺伪品,并可作为中药鉴别参考方法。 相似文献
914.
目的 将川贝母及其市场常见易混品进行鉴别区分,从而更好地对市场上川贝母药材的质量进行监控。方法 采用传统的性状鉴别与显微鉴别方法。结果 川贝母、伊贝母、平贝母、浙贝母、湖北贝母性状之间具有一定的差异,如表面颜色、外部鳞叶、气味,通过显微实验观察到的淀粉粒的形状、边缘形态,脐点大小、明显程度,层纹的明显程度以及螺纹或螺纹—环纹导管的大小,可将川贝母类与常见不同种类的贝母进行初步鉴别。结论 采用传统的性状、显微鉴别手段可对川贝母及其市场常见易混品进行粗略区分,初步减少川贝母市场药用混乱情况。 相似文献
915.
Alexander Ryan 《Scandinavian political studies》2023,46(1-2):52-74
After a period in which affective polarization—defined here as the difference between positive feelings toward in-parties and negative out-party animus—has mostly focused on the single US case, there has recently been an increase in large-N comparative analyses and single case studies in other countries, including in the Nordic region. This study adds to this by studying and comparing affective polarization in the Nordic countries. In line with what previous comparative and single case studies have already indicated, the results show that affective polarization has tended to be higher in Sweden and Denmark than in Norway, Iceland, and Finland. The article also tracks time trends for the association between ideological distance from parties and affective party evaluations. As expected, placing parties further from oneself on the left-right scale has been more strongly associated with party affect in Denmark and Sweden. Furthermore, the results show that there are some variations between the countries in terms of how distance from parties on other ideological dimensions than left-right placement is associated with out-party affect. 相似文献
916.
Christina A. Malone M.F.S. 《Journal of forensic sciences》2015,60(2):326-330
Skin features have been employed by law enforcement agencies for suspect and victim identification. Comparisons of hand have arisen in casework where images have been submitted where a face was not present but a hand was visible. This research utilizes a collection of 128 hands from employees of the U.S. Army Criminal Investigation Laboratory to examine the frequency and distribution of skin detail on the dorsal surface of the hand. To assess the location of features, the hand was segmented into 14 regions using readily discernible anatomical landmarks. Overall, 2618 pigmented lesions and 92 scars or injuries were documented. When comparing the regions with one another, Regions 1–10 had fewer pigmented lesions than Regions 11–14. There was no pattern to the distribution of scars throughout the regions. The findings presented a foundation for one possible method that may differentiate hands based on the frequency and distribution of such features. 相似文献
917.
Likelihood ratio (LR) plays an important role in estimating the weight of evidence in firearm evidence identifications. LR is computed from a statistical model including the distribution of the known-matching (KM or within) and known-nonmatching (KNM or between) comparison scores. Current LR procedures rely on KM/KNM scores from existing reference firearm toolmark data sets or alternatively from generating a set of test fires using multiple firearms. Both procedures may contain theoretical or practical issues which may hinder the LR procedures from reporting an unbiased LR estimation in casework. In this paper, a reference data set was established from a set of firearms, each test-fired two cartridge cases, resulting in a basic data set and a control data set. The congruent matching cells (CMC) method was used to generate CMC scores that are used to fit in the KM/KNM statistical distributions for LR estimation. In the initial test, 130 firearms from eight manufacturers were used for generating a reference data set consisting of 260 cartridge cases representing 130 KM and 8385 KNM pairwise breech face images. Test results showed that the KM and KNM distribution intersect at CMC = 2, which is equivalent to LR = 1 (equally to support both the prosecutor and the defense propositions). When the CMC threshold is increased to 6 or more, the LR values are higher than a million, which can provide extremely strong support to the conclusion of the same firearm (or the prosecutor's proposition) in the casework of firearm evidence identification. 相似文献
918.
We show how both the Chicago Police Department and the New York Police Department sought to settle uncertainty about their propriety and purpose during a period when abrupt transformations destabilized urban order and called the police mandate into question. By comparing annual reports that the Chicago Police Department and the New York Police Department published from 1877 to 1923, we observe two techniques in how the police enacted that settlement: identification of the problems that the police believed themselves uniquely well equipped to manage and authorization of the powers necessary to do so. Comparison of identification and authorization yields insights into the role that these police departments played in convergent and divergent constructions of disorder and, in turn, into Progressivism's varying effects in early urban policing. 相似文献
919.
Carlos M. A. Girelli Ph.D. Breno R. Segatto Ph.D. 《Journal of forensic sciences》2019,64(5):1520-1522
During the period of one year, the Police of the State of Espírito Santo in Brazil analyzed 1,431 cartridge cases obtained from crime scenes and seizures. The cartridges were subjected to a development sequence (cyanoacrylate fuming + gun bluing + fluorescent dying), and panoramic images of the developed fingermarks were generated based on the photographs taken during the rotation of the cartridges. Ridge details were observed in 50 cartridges, but only in 5 cartridges, the marks were considered with value for identification. The fingermarks were searched in the Automated Fingerprint Identification System (AFIS) of the Brazilian Federal Police and, in one case, it was possible to obtain the suspect's identification. In our knowledge, this is the first case in Brazil of identification of a suspect based on a fingermark recovered from a fired cartridge case. 相似文献
920.
本文从学科领域入手,对指纹自动识别技术在发展过程中受人工智能技术影响所产生的新变化进行简述。指纹识别技术作为一种计算机应用技术,其发展与计算机科学的新技术密切相关。人工智能技术,特别是基于深度学习的图像技术的发展使指纹识别算法开启了全新的模式。本文将人工智能在指纹领域的发展分成三个阶段,并对当前所处的第二阶段的发展趋势进行了分析。基于深度学习的指纹识别技术使用图像特征而不是传统细节点特征的方式,改变了法庭科学领域对指纹识别的认知。本文重点对深度学习技术在指纹识别方面的应用模式和典型的技术方法进行了论述,给出了基于深度学习的指纹识别技术方案图,对技术方案中的网络模型设计等重要步骤逐一进行了说明,提出了图像处理、降维等几个需要重点攻坚的技术环节。对现有的可为指纹识别借鉴使用的深度网络模型进行了介绍,如:卷积神经网络、自编码器网络。最后对人工智能指纹识别算法与传统算法的性能进行了对比。 相似文献