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    题名 作者 年代 出处 被引量
12019新型冠状病毒基因组特征和流行病学:病毒起源和受体结合的意义显示文摘研究者对来自9例新型冠状病毒肺炎住院患者的支气管肺泡灌洗液样本和培养的分离株进行了下一代测序。从这些个体中获得了严重急性呼吸综合征-冠状病毒2(severe acute respiratory syndrome-coronavirus 2,SARS-CoV-2)的完整和部分基因组序列。利用Sanger测序连接病毒重叠群以获得全长基因组,cDNA末端快速扩增确定终端区。对这些SARSCoV-2基因组和其他冠状病毒基因组进行了系统进化分析,以确定该病毒的进化史并有助于推断其可能的起源。刘青(译) 刘莉(审校) Lu R Zhao X Li J Niu P Yang B Wu H Wang W Song H Huang B Zhu N Bi Y Ma X Zhan F Wang L Hu T Zhou H Hu Z Zhou W Zhao L Chen J Meng Y Wang J Lin Y Yuan J Xie Z Ma J Liu WJ Wang D Xu W Holmes EC Gao GF Wu G Chen W Shi W Tan W 2020中华高血压杂志2020,28,3:516
2甘肃大地湾遗址距今6万年来的考古记录与旱作农业起源显示文摘报道了中国北方早期旱作农业起源地之一的甘肃秦安大地湾遗址Dadiwan06探方的最新发掘成果,根据黄土-古土壤序列、绝对测年(AMS 14C和光释光测年)、气候事件年龄和考古分析,为Dadiwan06探方的地层沉积建立了6.5万年的年代框架.考古材料分析显示,Dadiwan06探方完整记录了石英打制技术制品、细石器技术制品、大地湾一期文化以及仰韶文化陶器制品等分别代表中国北方原始采集狩猎经济、先进采集狩猎经济、早期栽培经济与成熟农业经济的4个不同发展阶段,反映了大地湾遗址距今6.0万年以来由采集狩猎经济逐步向农业经济过渡的持续人类活动历史。张东菊 陈发度 BETTINGER R L BARTON L 吉笃学 MORGAN C 王辉 程晓钟 董广辉 GUILDERSON T P 赵晖 2010科学通报2010,55,10:42
3AGNP精神科治疗药物监测共识指南:2011显示文摘治疗药物监测(Therapeutic drug monitoring,TDM),如通过定量测定血清或血浆药物浓度指导用药剂量优化,已经成为对患者进行精神药物治疗的很有价值的工具。在患者用药依从性难以判断、药物耐受性不佳、治疗剂量下无效以及可能存在药代动力学药物-药物相互作用等情况下,测定药物浓度是很有用的。在精神科,有可能明显获益于TDM的主要患者群体包括儿童、孕妇、老年患者、智力障碍患者、涉及司法的患者、已知或怀疑携带药代动力学相关基因变异的患者,以及合并躯体疾病影响药代动力学的患者。然而,只有将TDM充分整合到临床治疗过程中去,才能发挥其优化药物治疗的潜在优势。为了促进TDM的合理应用,神经精神药理学与药物精神病学协会(Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie,AGNP)的TDM专家组在2004年发表了精神药物治疗药物监测指南。之后,随着知识不断更新,又有许多可能需要进行TDM的新药上市。因此,本次更新将神经精神药物的种类扩展到了128种,并将其TDM必要性划分为从'强烈推荐'到'可能有用'的四个等级。经过大量细致且全面的文献检索与分门别类的汇总整理,将基于循证医学理念的'治疗参考浓度范围'和'剂量相关参考浓度范围'呈现给大家。本共识指南引入了'实验室警戒浓度'的新概念,即实验室需要马上告知治疗医生的药物浓度上限。本共识指南还给出了诸如药物作为细胞色素P450酶的底物和抑制剂的性质,代谢物与母药浓度比值的常见范围,以及与结果解释相关的内容,还提供了何时将TDM与遗传药理学检测相结合的建议。遵循本指南,有助于改善许多患者精神药物治疗的效果,特别是那些存在药代动力学异常的患者。TDM是一门交叉学科,有时针对看起来不一致的数据,需要多学科坦诚地讨论,只有这样,患者才能从这种合作中获益。Hiemke C Baumann P Bergemann N Conca A Dietmaier O Egberts K Fric M Gerlach M Greiner C Gründer G Haen E Havemann-Reinecke U Jaquenoud Sirot E Kirchherr H Laux G Lutz UC Messer T Müller MJ Pfuhlmann B Rambeck B Riederer P Schoppek B Stingl J Uhr M Ulrich S Waschgler R Zernig G 李文标(译) 果伟(译) 阮灿军(译) 贺静(译) 汤宜朗(审校) 王传跃(审校) 2016实用药物与临床2016,19,10:37
4OPTICAL PROPERTIES OF GeO_2 AND Ge NANOCRYSTALS显示文摘he co m pound m aterial of n m size particles Ge O2 Si O2 w as synthesied through hydrolysis of Si( O C2 H4) and Ge Cl4 . A heat treatm ent w as carried out for the sa m ples at 100 ~1200 ℃in air . Its optical property w as deter mined by U V Vis spectur m . We have found that theabsorption edge of spectru m shifted progressively to longer w avelengths . The quantu m size ef fect of nanocrystals appears because crystals gro w and energy of optical band gap reduces d ueto the influence of te m perature . By the analysis of X ray diffraction w e have observed theprocess in w hich the structure of particles changed fro m disorder into order .Y.H.Zhou 1) ,Y.Y.Feng 2) and H.Y.Lu 2) 1)Department of Physics Nanjing Normal University, Nanjing 210097,China 2)Physics and Ch寁O P T I C A L P R O P E R T I E S O F Ge O2 A N D Ge N A N O C R Y S T A L S Y. H. Zhou1) , Y. Y. Feng2) 1999Acta Metallurgica Sinica(English Letters)1999,12,5:22
5幽门螺杆菌感染处理的当前观念——MaastrichtⅢ共识报告显示文摘名词缩写欧洲幽门螺杆菌研究小组:European Helicobacter Study Group,EHSG胃食管反流病:gastro-esophageal reflux disease。P Malfertheiner F Megraud C O'Morain F Bazzoli E El-Omar D Graham R Hunt T Rokkas N Vakil EJ Kuipers 朱琦 2007胃肠病学2007,12,3:15
6EFNS的神经病理性痛药物治疗指南:2010修订显示文摘背景和目的欧洲神经病学协会联盟第2届工作组的目的是对2005年以来的关于神经病理性痛的药物治疗证据进行更新。方法使用Cochrane数据库和Medline选择相关研究,并根据病因学对研究分类。所有Ⅰ类和Ⅱ类随机对照研究(RCTs)均入选,低级别研究仅在没有高级别研究的情况下入选。考虑到对门诊患者治疗的可行性,只选择单药治疗或重复给药的研究。结果多数大型RCT的研究对象是糖尿病性多发性神经病和疱疹后神经痛的患者,越来越多的小型研究则对其他病因导致的神经病理性痛的治疗进行了探索。总体而言,药物治疗在除三叉神经痛、慢性神经根病和人类免疫缺陷病毒(HIV)神经病以外的各种病因中疗效相当,A级证据支持下列药物用于治疗神经病理性痛:三环类抗抑郁剂(TCA)、普瑞巴林、加巴喷丁、曲马多和阿片类(在不同情况下)、度洛西汀、文拉法辛、局部利多卡因和辣椒素贴剂(在限定的情况下)。联合用药有效仅见于TCA与加巴喷丁、加巴喷丁与阿片类(A级证据)。结论目前仍然缺乏大型的对比研究。我们建议今后的研究使用标准化工具对共病情况、生活质量、临床症状和体征进行评估,并致力于更好地确定对特定药物治疗的反应情况。李建萍 李颖 林智 李焰生 Attal N Cruccua G Barona R Haanpa M Hanssona P Jensena S Nurmikk T 2012神经病学与神经康复学杂志2012,9,1:14
7内脏脂肪组织通过产生骨桥蛋白调控成纤维细胞衰老促进心脏衰老显示文摘老化通过增加包括骨桥蛋白(osteopontin,OPN)在内的细胞外基质(extracellular matrix,ECM)蛋白的沉积引起心脏结构和功能改变进而导致进行性间质纤维化。虽然已知OPN参与各种病理状况,但其在心肌衰老中的作用仍不清楚。Sawaki D Czibik G Pini M Ternacle J Suffee N Mercedes R Marcelin G Surenaud M Marcos E Gual P Clément K Hue S Adnot S Hatem SN Tsuchimochi I Yoshimitsu T Hénégar C Derumeaux G 刘青 叶鹏 2018中华高血压杂志2018,26,3:14
8mi R-122 negatively correlates with liver fibrosis as detected by histology and FibroScan显示文摘AIM: To investigate whether expression of selected mi RNAs obtained from fibrotic liver biopsies correlate with fibrosis stage.METHODS: Altogether, 52 patients were enrolled in the study representing various etiologic backgrounds of fibrosis: 24 cases with chronic hepatitis infections(types B, C), 19 with autoimmune liver diseases(autoimmune hepatitis, primary biliary cirrhosis, primary sclerosing cholangitis, overlapping syndrome cases), and 9 of mixed etiology(alcoholic and nonalcoholic steatosis, cryptogenic cases). Severity of fibrosis was determined by both histologic staging using the METAVIR scoring system and noninvasive transient elastography. Following RNAisolation, expression levels of mi R-21, mi R-122, mi R-214, mi R-221, mi R-222, and mi R-224 were determined using Taq Man Micro RNA Assays applying mi R-140 as the reference. Selection of mi RNAs was based on their characteristic up- or downregulation observed in hepatocellular carcinoma. Relative expression of mi RNAs was correlated with fibrosis stage and liver stiffness(LS) value measured by transient elastography, as well as with serum alanine aminotransferase(ALT) level.RESULTS: The expression of individual mi RNAs showed deregulated patterns in stages F1-F4 as compared with stage F0, but only the reduced level of mi R-122 in stage F4 was statistically significant(P < 0.04). When analyzing mi RNA expression in relation to fibrosis, levels of mi R-122 and mi R-221 showed negative correlations with fibrosis stage, and mi R-122 was found to correlate negatively and mi R-224 positively with LS values(all P < 0.05). ALT levels displayed a positive correlation with mi R-21(P < 0.04). Negative correlations were observed in the fibrosis samples of mixed etiology between mi R-122 and fibrosis stage and LS values(P < 0.05), and in the samples of chronic viral hepatitis, between mi R-221 and fibrosis stage(P < 0.01), whereas mi R-21 showed positive correlation with ALT values in the samples of autoimmune liver diseases(P < 0.03). The results also revealed a strong correlation between fibrosis stage and LS values(P < 0.01) when etiology of fibrosis was not taken into account.CONCLUSION: Reduced expression of mi R-122 in advanced fibrosis and its correlation with fibrosis stage and LS values seem to be characteristic of hepatic fibrosis of various etiologies.Tünde Halász Gábor Horváth Gabriella Pár Klára Werling András Kiss Zsuzsa Schaff Gábor Lendvai 2015World Journal of Gastroenterology2015,21,25:11
9烟酰胺磷酸核糖基转移酶促进肺血管重塑,是肺动脉高压的治疗靶点显示文摘肺动脉高压(pulmonary arterial hypertension,PAH)是一种严重的进行性疾病,其标志之一是肺血管重塑。烟酰胺磷酸核糖基转移酶(nicotinamide phosphoribosyl transferase,NAMPT)是调节细胞内烟酰胺腺嘌呤二核苷酸水平、细胞氧化还原状态,调节组蛋白脱乙酰酶,促进细胞增殖和抑制凋亡的一种细胞酶。研究人员假设NAMPT可促进肺血管重塑,Chen J Sysol JR Singla S Zhao S Yamamura A Valdez-Jasso D Abbasi T Shioura KM Sahni S Reddy V Sridhar A Gao H Torres J Camp SM Tang H Ye SQ Comhair S Dweik R Hassoun P Yuan JX Garcia JG Machado RF 刘莉 叶鹏 2017中华高血压杂志2017,25,2:10
102001年1月26日高纬磁层顶通量管事件的观测研究显示文摘20 0 1年 1月 2 6日 11:10~ 11:4 0UT ,ClusterⅡ卫星簇位于午后高纬磁鞘边界层和磁鞘区 ,此时行星际磁场Bz 为南向 .本文对在此期间观测到的多次磁通量管事件作了详细的研究 ,获得一系列的新发现 :(1)高纬磁鞘边界层磁通量管的出现具有准周期性 ,周期约为 78s,比目前已知的磁层顶向阳面FTE的平均周期 (8~ 11min)小得多 .(2 )这些通量管都具有强的核心磁场 ;其主轴多数在磁场最小变化方向 ,少数在中间变化方向 ,有些无法用PAA判定其方向 (需要用电流管PAA确定 ) ,这与卫星穿越通量管的相对路径有关 .(3)每个事件都存在很好的HT参考系 ,在HT参考系中这些通量管是准定常态结构 ;所有通量管都沿磁层顶表面运动 ,速度方向大体相同 ,都来自晨侧下方 .通量管的径向尺度为 1~ 2RE,与通常的FTE通量管相当 .(4 )起源于磁层的强能离子大体上沿着管轴方向由磁层向磁鞘运动 ;起源于太阳风的热等离子体沿管轴向磁层传输 .通量管为太阳风等离子体向磁层输运和磁层粒子向行星际空间逃逸提供了通道 .(5 )每个通量管事件都伴随有晨昏电场的反转 ,该电场为对流电场 .黄宗英 濮祖荫 肖池阶 宗秋刚 傅绥燕 谢伦 史全岐 曹晋滨 刘振兴 沈超 史建魁 路立 王迺权 陈涛 T Fritz K-H Glassmeier P Daly H Rème 2004地球物理学报2004,47,2:7
11Archaeological records of Dadiwan in the past 60 ka and the origin of millet agriculture显示文摘This paper reports the recent excavation of Unit Dadiwan06 at the Dadiwan site in Qin’an County, Gansu.A 65 ka chronological framework is established for Dadiwan06 on the basis of absolute dating (AMS 14C and OSL), stratigraphy, climate change events and archaeology.Artifact distributions reveal patterns of human behavioral variation and adaptation over the past 60 ka, from primitive hunting and gathering to advanced hunting and gathering, to primitive Neolithic agriculture, and finally to advanced Neolithic agriculture.ZHANG DongJu CHEN FaHu BETTINGER R L BARTON L JI DuXue MORGAN C WANG Hui CHENG XiaoZhong DONG GuangHui GUILDERSON T P ZHAO Hui 2010Chinese Science Bulletin2010,55,16:6
12Osteoprotegerin: A Novel Secreted Protein Involved in the Regulation of Bone Density显示文摘W.S Simonet D.L Lacey C.R Dunstan M Kelley M.-S Chang R Lüthy H.Q Nguyen S Wooden L Bennett T Boone G Shimamoto M DeRose R Elliott A Colombero H.-L Tan G Trail J Sullivan E Davy N Bucay L Renshaw-Gegg T.M Hughes D Hill W Pattison P Campbell S Sander G Van 1997Cell1997,,2:6
13Diagnosis of focal liver lesions with deep learning-based multichannel analysis of hepatocyte-specific contrast-enhanced magnetic resonance imaging显示文摘BACKGROUND The nature of input data is an essential factor when training neural networks.Research concerning magnetic resonance imaging(MRI)-based diagnosis of liver tumors using deep learning has been rapidly advancing.Still,evidence to support the utilization of multi-dimensional and multi-parametric image data is lacking.Due to higher information content,three-dimensional input should presumably result in higher classification precision.Also,the differentiation between focal liver lesions(FLLs)can only be plausible with simultaneous analysis of multisequence MRI images.AIM To compare diagnostic efficiency of two-dimensional(2D)and three-dimensional(3D)-densely connected convolutional neural networks(DenseNet)for FLLs on multi-sequence MRI.METHODS We retrospectively collected T2-weighted,gadoxetate disodium-enhanced arterial phase,portal venous phase,and hepatobiliary phase MRI scans from patients with focal nodular hyperplasia(FNH),hepatocellular carcinomas(HCC)or liver metastases(MET).Our search identified 71 FNH,69 HCC and 76 MET.After volume registration,the same three most representative axial slices from all sequences were combined into four-channel images to train the 2D-DenseNet264 network.Identical bounding boxes were selected on all scans and stacked into 4D volumes to train the 3D-DenseNet264 model.The test set consisted of 10-10-10 tumors.The performance of the models was compared using area under the receiver operating characteristic curve(AUROC),specificity,sensitivity,positive predictive values(PPV),negative predictive values(NPV),and f1 scores.RESULTS The average AUC value of the 2D model(0.98)was slightly higher than that of the 3D model(0.94).Mean PPV,sensitivity,NPV,specificity and f1 scores(0.94,0.93,0.97,0.97,and 0.93)of the 2D model were also superior to metrics of the 3D model(0.84,0.83,0.92,0.92,and 0.83).The classification metrics of FNH were 0.91,1.00,1.00,0.95,and 0.95 using the 2D and 0.90,0.90,0.95,0.95,and 0.90 using the 3D models.The 2D and 3D networks'performance in the diagnosis of HCC were 1.00,0.80,0.91,1.00,and 0.89 and 0.88,0.70,0.86,0.95,and 0.78,respectively;while the evaluation of MET lesions resulted in 0.91,1.00,1.00,0.95,and 0.95 and 0.75,0.90,0.94,0.85,and 0.82 using the 2D and 3D networks,respectively.CONCLUSION Both 2D and 3D-DenseNets can differentiate FNH,HCC and MET with good accuracy when trained on hepatocyte-specific contrast-enhanced multi-sequence MRI volumes.Róbert Stollmayer Bettina K Budai Ambrus Tóth IldikóKalina Erika Hartmann Péter Szoldán Viktor Bérczi Pál Maurovich-Horvat Pál N Kaposi 2021World Journal of Gastroenterology2021,27,35:6
14肠道菌群促进血管紧张素Ⅱ诱导的高血压和血管功能障碍显示文摘肠道微生物对宿主生理反应及对免疫功能的发展来说必不可少。肠道菌群对血压和全身血管功能等这些由免疫细胞功能决定的生理过程的影响知之甚少。方法:与常规饲养的小鼠(conventionally raised rats,CONV-R)比较,未受任何细菌影响的无菌小鼠(GF)表现出较为严重的全身性辅助性T细胞1型滞后。刘莉 叶鹏 Karbach SH Schnfelder T Brandao I Wilms E Hrmann N Jckel S Schüler R Finger S Knorr M Lagrange J Brandt M Waisman A Kossmann S Schüfer K Münzel T Reinhardt C Wenzel P 2016中华高血压杂志2016,24,10:5
15High efficiency, high power 808nm laser array and stacked arrays optimized for elevated temperature operation显示文摘Operation of 808-nm laser diode pumping at elevated temperature is crucial to many applications. Reliable operation at high power is limited by high thermal load and low catastrophic optical mirror damage (COMD) threshold at elevated temperature range. We demonstrated high efficiency and high power operation at elevated temperature with high COMD power. These results were achieved through device design optimization such as growth conditions, doping profile, and materials composition of the quantum-well and other layers. Electrical-to-optical efficiency as high as 62% was obtained through lowered threshold current, lowered series resistance and increased slope efficiency. The performance of single broad-area laser diodes scales to that of high power single bars on water-cooled copper micro-channel heatsinks or conductively-cooled CS heatsinks. No reduction in bar performance or significant spectral broadening is seen when these micro-channel coolers are assembled into 6-bar and 18-bar CW stacks for the highest power levels.Crump P A Crum T R DeVito M Farmer J Grimshaw M Huang Z Igl S A Macomber S Thiagarajan P Wise D 2004光机电信息2004,21,6:4
16玉米DDGS饲粮添加木聚糖酶或β-葡聚糖酶对保育猪生产性能和养分利用率的影响显示文摘本试验开展保育猪玉米DDGS饲粮添加木聚糖酶和β-葡聚糖酶对生产性能和养分消化的影响研究。135只(起始体重7.2±0.2kg)保育猪随机分成5个处理组,每个处理组6个重复,每个重复4~5只,分别为正对照组(PC,玉米/豆粕+0%玉米DDGS)、负对照组(NC,以30%玉米DDGS替代部分玉米和豆粕,不添加酶制剂)、在负对照组基础上分别添加4000 U/kg木聚糖酶(XYL)、450 U/kgβ-葡聚糖酶(BGL)或4000 U/kg木聚糖酶+450 U/kgβ-葡聚糖酶(XB)的3个酶制剂组。试猪统一饲喂玉米豆粕型饲粮1周(阶段一)后过渡到试验饲粮,试验饲粮分两阶段(阶段二:7-21天和阶段三:21-35天),试验饲粮配制以总赖氨酸含量一致为基础,营养水平达到或超过NRC(1998),为了突出纤维降解酶的作用效果,阶段二与阶段三NC、XYL、BGL和XB四组试验饲粮的代谢能比PC组分别降低3.0%和4.7%。试验发现,NC组试猪生长速度显著低于PC组(P<0.001)。阶段三,BGL组与XB组试猪日增重比NC组分别提高7.7%和9.3%(P<0.001);试验全期,XB组试猪比NC猪日增重提高6.6%(P<0.001)。XYL与XB组干物质消化率比NC组分别提高1.6%和1.4%(P<0.001),添加酶制剂组能量消化率比NC组提高5.5%(P<0.001),同时,与NC组比较,酶制剂组饲粮粗蛋白质消化率提高5.9%,差异极显著(P<0.001)。XYL、BGL和XB三组与NC组相比,饲粮中性洗涤纤维、酸性洗涤纤维及半纤维素消化率分别提高33%、30%与34%(P<0.02)。同时,酶制剂添加组饲粮P消化率比NC组提高46%(P<0.01)。结果表明,玉米DDGS饲粮联合添加木聚糖酶和β-葡聚糖酶可以提高保育猪日增重,且β-葡聚糖酶起主导作用。虽然木聚糖酶和β-葡聚糖酶对保育猪日均采食量与增重耗料比没有影响,但至少部分降低了玉米DDGS对饲粮养分利用率及生产的负面影响。陈芳 Tsai T Dove C R Cline P M 2017广东饲料2017,26,4:4
17Comparison of different lymph node staging systems in prognosis of gastric cancer:a bi-institutional study from Hungary显示文摘Objective: The Union for International Cancer Control(UICC) Node(N) classification is the most common used staging method for the prognosis of gastric cancer. It demands adequate, at least 16 lymph nodes(LNs) to be dissected; therefore different staging systems were invented.Methods: Between March 2005 and March 2010, 164 patients were evaluated at the Department of General Surgery in the Kenézy Gyula Hospital and at the Department of General, Thoracic and Vascular Surgery in the Kaposi Mór Hospital. The 6th, 7th and 8th UICC N-staging systems, the number of examined LNs, the number of harvested negative LNs, the metastatic lymph node ratio(MLR) and the log odds of positive LNs(LODDS) were determined to measure their 5-year survival rates and to compare them to each other.Results: The overall 5-year survival rate for all patients was 55.5% with a median overall survival time of 102 months. The tumor stage, gender, UICC N-stages, MLR and the LODDS were significant prognostic factors for the 5-year survival with univariate analysis. The 6th UICC N-stage did not follow the adequate risk in comparing N2 vs. N0 and N3 vs. N0 with multivariate investigation. Comparison of performances of the residual N classifications proved that the LODDS system was first in the prediction of prognosis during the evaluation of all patients and in cases with less than 16 harvested LNs. The MLR gave the best prognostic prediction when adequate(more than or equal to 16) lymphadenectomy was performed.Conclusions: We suggest the application of LODDS system routinely in western patients and the usage of MLR classification in cases with extended lymphadenectomy.dezso tóth adrienn bíró zsolt varga miklós torok péterárkosy 2017Chinese Journal of Cancer Research2017,29,4:4
18Guidelines and Good Clinical Practice Recommendations for Contrast Enhanced Ultrasound (CEUS) - Update 2008显示文摘M Claudon D Cosgrove T Albrecht L Bolondi M Bosio F Calliada J.-M Correas K Darge C Dietrich M D’Onofrio D Evans C Filice L Greiner K J?ger N Jong E Leen R Lencioni D Lindsell A Martegani S Meairs C Nols?e F Piscaglia P Ricci G Seidel B Skjoldbye L Solbia 2008Ultraschall in Med2008,,01:4
19Proposed international clinical diabetic retinopathy and diabetic macular edema disease severity scales显示文摘C.P Wilkinson Frederick L Ferris Ronald E Klein Paul P Lee Carl David Agardh Matthew Davis Diana Dills Anselm Kampik R Pararajasegaram Juan T Verdaguer 2003Ophthalmology2003,,9:4
20岩石破裂以及破裂前信号的演变显示文摘地震是大量的岩石破裂事件。很多大地震之前都存在瞬态信号:电磁信号、磁场变化、电离层扰动、土壤导电率的变化以及其他震前信号。令监测人员奇怪的是,在震前短时间内一些震前信号会衰弱甚至消失不见。岩石中应力活化电流的发现提供了一个可能的解释,应力能够激活岩石中的移动电荷载体,即电子空位缺陷(electron va-cancy defects,EVD),也称空穴,用h.表示。h.相当于O2-中的O-,且以电钝性及休止的状态存在于无应力岩石中。当被激活时,h.沿着应力梯度方向流动,从而产生电流。在非常高的应力速率下,位错累积成微破裂,这正是灾变破裂的开始。当h.电荷载体无法再被激活时,震前破裂信号会明显衰弱。Freund F T Dahlgren R P Chu J j 张祯(译) 田家勇(校) 2011国际地震动态2011,,1:4
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