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Journal of Semiconductors 2019年第2期40卷 49-55页

作者： Taoreed O.Owolabi Physics and Electronics Department Adekunle Ajasin University Computer Information System Department College of Computer Science and Information Technology Imam Abdulrahman bin Faisal University Physics Department King Fahd University of Petroleum and Minerals

Energy band gap of titanium dioxide(TiO_2) semiconductor plays significant roles in many practical applications of the semiconductor and determines its appropriateness in technological and industrial applications such as UV absorption, pigment,photo-catalysis, pollution control systems and solar cells among others. Substitution of impurities into crystal lattice structure is the most commonly used method of tuning the band gap of TiO_2 for specific application and eventually leads to lattice distortion. This work utilizes the distortion in the lattice structure to estimate the band gap of doped TiO_2, for the first time, through hybridization of a particle swarm optimization algorithm(PSO) with a support vector regression(SVR) algorithm for developing a PSO-SVR model. The precision and accuracy of the developed PSO-SVR model was further justified by applying the model for estimating the effect of cobalt-sulfur co-doping, nickel-iodine co-doping, tungsten and indium doping on the band gap of TiO_2 and excellent agreement with the experimentally reported values was achieved. Practical implementation of the proposed PSO-SVR model would further widen the applications of the semiconductor and reduce the experimental stress involved in band gap determination of TiO_2.

关键词： band gap lattice distortion crystal lattice parameters particle swarm optimization support vector regression titanium dioxide

恶性肿瘤中gapLINC的调控作用及其与患者预后的关系

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中华病理学杂志 2019年第11期48卷 902-905页

作者：周原世徐书婉关沧海胡增涛姜兴明哈尔滨医科大学附属第二医院胆胰外科 150086

长链非编码RNA(long non-coding RNAs,lncRNA)是一类长度超过200个核苷酸且因缺乏开放性阅读框架而丧失蛋白编码能力的转录本,但是lncRNA能够在转录以及转录后等不同水平以诸多方式调控肿瘤的发生发展。gapLINC(gastric adenocarcinoma ... 详细信息

长链非编码RNA(long non-coding RNAs,lncRNA)是一类长度超过200个核苷酸且因缺乏开放性阅读框架而丧失蛋白编码能力的转录本,但是lncRNA能够在转录以及转录后等不同水平以诸多方式调控肿瘤的发生发展。gapLINC(gastric adenocarcinoma associated,positive CD44 regulator,long intergenic non-coding RNA)定位于人类染色体18p11.31,在多种恶性肿瘤(胃癌、结直肠癌、胆管癌等)中异常高表达并能够通过不同的作用机制调控肿瘤细胞的增殖、抗凋亡、侵袭和转移。此外,gapLINC还可作为生物标志物在肿瘤的早期诊断、靶向治疗及患者的预后评估等方面具有重要的应用前景。该文就gapLINC在恶性肿瘤中的调控作用及应用前景作一综述。

关键词：胆管癌人类染色体恶性肿瘤靶向治疗 CD44 抗凋亡 gap

Emergence of superconductivity from fully incoherent normal state in an iron-based superconductor (Ba_(0.6)K_(0.4))Fe_2As_2

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Science Bulletin 2019年第1期64卷 11-19页

作者： Jianwei Huang Lin Zhao Cong Li Qiang Gao Jing Liu Yong Hu Yu Xu Yongqing Cai Dingsong Wu Ying Ding Cheng Hu Huaxue Zhou Xiaoli Dong Guodong Liu Qingyan Wang Shenjin Zhang Zhimin Wang Fengfeng Zhang Feng Yang Qinjun Peng Zuyan Xu Chuangtian Chen Xingjiang Zhou Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences University of Chinese Academy of Sciences Technical Institute of Physics and Chemistry Chinese Academy of Sciences Songshan Lake Materials Laboratory Collaborative Innovation Center of Quantum Matter

In unconventional superconductors, it is generally believed that understanding the physical properties of the normal state is a pre-requisite for understanding the superconductivity mechanism. In conventional superconductors like niobium or lead, the normal state is a Fermi liquid with a well-defined Fermi surface and well-defined quasipartcles along the Fermi surface. Superconductivity is realized in this case by the Fermi surface instability in the superconducting state and the formation and condensation of the electron pairs(Cooper pairing). The high temperature cuprate superconductors, on the other hand, represent another extreme case that superconductivity can be realized in the underdoped region where there is neither well-defined Fermi surface due to the pseudogap formation nor quasiparticles near the antinodal regions in the normal state. Here we report a novel scenario that superconductivity is realized in a system with well-defined Fermi surface but without quasiparticles along the Fermi surface in the normal state.High resolution laser-based angle-resolved photoemission measurements have been performed on an optimally-doped iron-based superconductor(Ba_(0.6)K_(0.4))Fe_2As_2. We find that, while sharp superconducting coherence peaks emerge in the superconducting state on the hole-like Fermi surface sheets, no quasiparticle peak is present in the normal state. Its electronic behaviours deviate strongly from a Fermi liquid system. The superconducting gap of such a system exhibits an unusual temperature dependence that it is nearly a constant in the superconducting state and abruptly closes at Tc. These observations have provided a new platform to study unconventional superconductivity in a non-Fermi liquid system.

关键词： (Ba0.6K0.4)Fe2As2 ARPES Superconducting gap Normal state Non-Fermi liquid

How does Helicobacter pylori cause gastric cancer through connexins: An opinion review

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World Journal of Gastroenterology 2019年第35期25卷 5220-5232页

作者： Huan Li Can-Xia Xu Ren-Jie Gong Jing-Shu Chi Peng Liu Xiao-Ming Liu Department of Gastroenterology the Third Xiangya Hospital of Central South University

Helicobacter pylori (H. pylori) is a Gram-negative bacterium with a number of virulence factors, such as cytotoxin-associated gene A, vacuolating cytotoxin A, its pathogenicity island, and lipopolysaccharide, which cause gastrointestinal diseases. Connexins function in gap junctional homeostasis, and their downregulation is closely related to gastric carcinogenesis. Investigations into H. pylori infection and the fine-tuning of connexins in cells or tissues have been reported in previous studies. Therefore, in this review, the potential mechanisms of H. pylori-induced gastric cancer through connexins are summarized in detail.

关键词： Helicobacter pylori Connexin gap junctional intercellular communications gap junction proteins Gastric cancer Transcription factors DNA methylation Proliferation Apoptosis

Relationship between early structural changes at cornea incision sites and surgical outcomes after phacoemulsification

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International Journal of Ophthalmology(English edition) 2019年第7期12卷 1139-1145页

作者： Kyung Hyun Jin Tae Gi Kim Department of Ophthalmology Kyung Hee University Medical Center Kyung Hee University Seoul 02447 Korea Department of Ophthalmology Kyung Hee University Hospital at Gangdong Kyung Hee University Seoul 05278 Korea

AIM: To assess the early structural changes at clear corneal cataract incision sites and surgical outcomes using anterior segment optical coherence tomography(AS-OCT).METHODS: We evaluated 80 eyes of 59 patients who underwent phacoemulsification with a clear corneal incision. All incisions were evaluated 1 wk, 1, and 3 mo postoperatively using AS-OCT and analyzed regarding angle, length of the incision, maximal corneal thickness at the incision, and if present, corneal endothelial gap length and incision gap area. The patients were divided into two groups according to whether or not an endothelial gap was present at 1 wk postoperatively(endothelial gap, group 1;no endothelial gap, group 2). We analyzed the difference in patient and surgical factors between the two groups, and compared the surgical outcome and the refractive outcome.RESULTS: An endothelial gap was observed in 56(70.0%) of 80 eyes at 1 wk postoperatively but not at 3 mo postoperatively. The mean patient age was significantly higher in group 1 than in group 2. The longer the length of the corneal incision and the steeper the incision angle, the greater the length and area of the endothelial gap. In group 1, the mean change in mean keratometry of the anterior cornea was significantly greater than in group 2, and the spherical equivalent(SE) and mean numerical error indicated significant myopic changes at 1 wk postoperatively. CONCLUSION: The risk of an endothelial gap increases with patient age and a long corneal incision and steep incision angle. The presence of an endothelial gap aftersurgery may affect the early postoperative corneal curvature and SE.

关键词： corneal incision structure phacoemulsification corneal curvature corneal endothelial gap anterior segment optical coherence tomography

基于点击化学的gap基复合交联体系力学性能研究

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基于点击化学的GAP基复合交联体系力学性能研究

作者：范家珂中北大学

学位级别：硕士

聚叠氮缩水甘油醚(gap)具有高密度、高生成焓、低摩擦感度以及低撞击感度等优点,在高能复合固体推进剂中具有广泛的应用前景。点击化学反应具有副产物无害、不受水分影响等优点,是替代异氰酸酯类固化反应的有效手段。六硝基六氮杂异伍兹... 详细信息

聚叠氮缩水甘油醚(gap)具有高密度、高生成焓、低摩擦感度以及低撞击感度等优点,在高能复合固体推进剂中具有广泛的应用前景。点击化学反应具有副产物无害、不受水分影响等优点,是替代异氰酸酯类固化反应的有效手段。六硝基六氮杂异伍兹烷(CL-20)是一种具有高能量密度、优异爆轰性能等特点的新型含能化合物,将其加入复合固体推进剂中可以显著提高推进剂的能量性能。本文以gap为含能黏结剂、以CL-20为高能炸药,选择炔基化合物BPS为固化剂,对gap-BPS及gap-BPS/CL-20固化体系的力学性能及影响因素进行了研究,具体内容如下:(1)采用分子动力学,分别搭建了gap-BPS(以下简称GB)共混体系及gap-BPS/CL-20(简称GB/CL-20)层状体系。并根据Huisgen环加成反应机理,编写了Perl交联脚本,对GB共混体系及GB/CL-20层状体系进行“交联”,研究了固化参数R值对交联度的影响规律。结果表明,R值小于0.3时,GB交联体系及GB/CL-20交联体系的交联度均为100%;当R值大于0.3时,GB交联体系的交联度大于GB/CL-20交联体系的交联度,且GB/CL-20交联体系的交联度均小于100%。表明,体系中BPS用量较多时,CL-20的加入会阻碍GB交联网络的生长,不利于交联网络的生成。(2)采用分子动力学对交联后的GB模型与GB/CL-20模型的力学性质进行了计算。结果表明,随着R值的增大,两种体系断裂强度与抵抗弹性形变的能力均先增大后减小。当R值为0.3时,GB交联体系的断裂强度、硬度最大,且此时体系抵抗弹性形变的能力最强,力学性能最佳;当R值为0.5时,GB/CL-20交联体系的硬度与抵抗弹性形变的能力最强。在相同R值下,CL-20的加入使得体系断裂强度降低,抵抗弹性形变与塑性形变的能力增强。(3)采用非平衡分子动力学,对交联后GB交联模型与GB/CL-20模型拉伸性能进行了计算。拉伸的微观行为显示,GB交联体系的交联度为100%时,体系中的gap分子链经由BPS连接为一个交联网络,在拉伸过程中多以交联网络出现,难以被拉开。GB/CL-20交联体系的拉伸行为表明,在GB交联网络与CL-20晶体界面处最先出现裂缝,随着拉伸的进行,裂缝逐渐扩大,最终GB/CL-20交联网络被拉断。由于GB交联网络中叠氮基与CL-20间存在氢键、范德华力等非化学键相互作用,裂缝扩大过程中会出现“拉丝”现象,这将在一定程度上阻止裂缝扩大的速度。GB/CL-20交联体系被拉断后,与CL-20存在非化学键相互作用的“丝”会出现回缩现象,这是由于“回缩”现象符合能量最小化原则。同时,非平衡拉伸模拟计算结果与弹性力学计算结果一致,R值为0.3时,GB交联体系抵抗弹性形变的能力最佳;R值为0.5时,GB/CL-20交联体系抵抗弹性形变的能力最佳。(4)基于模拟计算结果,采用万能材料试验机对GB/CL-20、GB/CL-20、GB/CL-20、GB/CL-20胶片的力学性能进行了测试,研究了R值对力学性能的影响。结果表明,R值为0.5时,GB/CL-20试样的杨氏模量最大,且随R值的增大,杨氏模量先增大后减小。与GB/CL-20交联体系的非平衡单轴拉伸类似,胶片受到拉伸力时,裂缝最先在胶片边缘出现,并随拉伸过程不断扩大直到胶片断裂。激光共聚焦显微镜测试结果表明GB/CL-20表面粗糙度最大,表明拉伸过程中“拉丝”现象严重,两断面的分子间结合作用强。

关键词： gap 点击化学分子动力学力学性能

Investigation on the interface damage in drilling low-stiffness CFRP/Ti stacks

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Chinese Journal of Aeronautics 2019年第9期32卷 2211-2221页

作者： Bin LUO Kaifu ZHANG Shunuan LIU Hui CHENG Runxiao WANG School of Mechanical Engineering Northwestern Polytechnical University

Carbon fiber reinforced plastic and titanium alloy(CFRP/Ti) stacks have been widely used as aerospace structures because of their excellent combination of physical properties. Interface damage caused by interface gaps, significantly different from that of metal/metal stacks, is a common problem in the through-hole drilling of CFRP/Ti stacks with low stiffness. In this study, a force–deformation coupling model was developed to further examine the formation mechanism and the control method of interface damage. Firstly, the coupling model was built considering the interaction between the thrust force and the deformation. To solve this model, a numerical method was proposed in which specific cutting coefficients were calibrated using only the thrust force of rigid stacks. Secondly, drilling experiments were performed with different feed rates and bending stiffness. Experimental results indicate that interface damage mainly includes interlayer chips and surface damage of CFRP layers. The surface damage, which is irreparable, is caused by the rotary extension of metal chips along the interlayer gap. Thirdly, variations of the interface gap were calculated with the coupling model that had been verified by measured thrust forces. The damage area was found to have a linear dependence relation with the interlayer gap. However, in conditions of large gap sizes, the interface damage areas increased with the interlayer gap at high feed rates, while decreasing slightly at low feed rates. This phenomenon was satisfactorily explained by the presented model. Finally, a method was proposed to determine the appropriate pressure exceeding which no interlayer damage will occur. Additional drilling experiments proved the method effective. This study leads to further understanding of the forming mechanism of interlayer damage and of selecting appropriate parameters in drilling low-stiffness composite/metal stacks.

关键词： Coupling effects Drilling Interface damage Interlayer gap Thin walled structures

中药材规范化种植(gap)几个关键问题商榷

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中国中药杂志 2016年第7期41卷 1173-1177页

作者：杨光郭兰萍周修腾黄璐琦中国中医科学院中药资源中心道地药材国家重点实验室培育基地北京100700

该文回顾了中药材gap产生的历史背景,分析了5个P(GMP,GLP,GSP,GCP,gap)发展的经验,应用经济学理论对中药材gap进行了分析,指出中药材gap遇到问题的核心是忽略经济规律,曾经的中药材gap是过程认证,gap公告无法形成质量信号在产品市场中传... 详细信息

该文回顾了中药材gap产生的历史背景,分析了5个P(GMP,GLP,GSP,GCP,gap)发展的经验,应用经济学理论对中药材gap进行了分析,指出中药材gap遇到问题的核心是忽略经济规律,曾经的中药材gap是过程认证,gap公告无法形成质量信号在产品市场中传递,消费者无法在终端市场找到gap与非gap药材的区别,厂商缺乏gap认证的动力。该文提出了应在经济学的指导下,重新设计gap的认证制度,由第三方认证机构承担认证,将gap定位为优质标准,药监部门的角色从许可基地到监督和管理第三方认证机构,提出完善gap认证的信号传导机制,实现gap与市场的接轨。

关键词： gap 资源经济中药资源资源管理第三方认证

Self-trapped spatially localized states in combined linear-nonlinear periodic potentials

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Frontiers of physics 2020年第1期15卷 17-24页

作者： Jin-Cheng Shi Jian-Hua Zeng State Key Laboratory of Transient Optics and Photonics Xi’an Institute of Optics and Precision Mechanics of CASXi’an 710119China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory for Physical Electronics and Devices of the Ministry of Education&Shaanxi Key Lab of Information Photonic Technique Xi’an Jiaotong UniversityXi’an 710049China

We analyze the existence and stability of two kinds of self-trapped spatially localized gap modes,gap solitons and truncated nonlinear Bloch waves,in one-and two-dimensional optical or matter-wave media with self-focusing nonlinearity,supported by a combination of linear and nonlinear periodic lattice potentials.The former is found to be stable once placed inside a single well of the nonlinear lattice,it is unstable otherwise.Contrary to the case with constant self-focusing nonlinearity,where the latter solution is always unstable,here,we demonstrate that it nevertheless can be stabilized by the nonlinear lattice since the model under consideration combines the unique properties of both the linear and nonlinear lattices.The practical possibilities for experimental realization of the predicted solutions are also discussed.

关键词： gap solitons and gap waves Bose-Einstein condensates linear and nonlinear periodic potentials

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端丙炔基聚丁二烯预聚物的贮存稳定性

火炸药学报 2019年第5期42卷 460-464,I0003页

作者：高文博李永辉何吉宇杨荣杰北京理工大学材料学院

为确定端丙炔基聚丁二烯(PTPB)在常温下的贮存稳定性,通过跟踪测试研究了PTPB在室温(15~30℃)、5℃他-10℃下的贮存稳定性。采用13 C-NMR、FT-IR、TG、GPC和黏度测试对贮存在不同温度下、不同时间的PTPB的化学结构和性质进行了表征分析... 详细信息

为确定端丙炔基聚丁二烯(PTPB)在常温下的贮存稳定性,通过跟踪测试研究了PTPB在室温(15~30℃)、5℃他-10℃下的贮存稳定性。采用13 C-NMR、FT-IR、TG、GPC和黏度测试对贮存在不同温度下、不同时间的PTPB的化学结构和性质进行了表征分析,并将贮存的PTPB预聚物分别与聚叠氮缩水甘油醚(gap)制成PTPB弹性体,采用FTIR、DMA和力学测试对弹性体进行表征。结果表明,在室温下贮存4个月的PTPB,与在5℃和-10℃贮存4个月的PTPB化学结构及性质一致,未发生聚合、交联、断链、氧化反应,黏度也未发生变化;由其制成的PTPB弹性体在3种温度下贮存4个月后,其分子结构、动态力学性能及室温力学性能也保持一致。因此PTPB能够在常温下稳定贮存,不需在低温贮存。

关键词：分析化学端丙炔基聚丁二烯 PTPB 弹性体贮存稳定性 gap