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The First Outbreak of Omicron Subvariant BA.5.2—Beijing Municipality,China,July 4,2022 被引量:5
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作者 Zhaomin Feng Ying Shen +8 位作者 Shuang Li Jia Li shaohua wang Zhenquan Zhang Yunkui Shen Fu Li Yang Pan Quanyi wang Da Huo 《China CDC weekly》 2022年第30期667-668,共2页
On July 4,2022,the first case of Omicron subvariant BA.5.2 in Beijing Municipality was discovered in Yanqing District.The case was a 49-yearold Chinese male who had arrived in Shanghai Municipality via international f... On July 4,2022,the first case of Omicron subvariant BA.5.2 in Beijing Municipality was discovered in Yanqing District.The case was a 49-yearold Chinese male who had arrived in Shanghai Municipality via international flight DL9927 from North Carolina,U.S.on June 15.He stayed in a hotel for the 14-day arrival quarantine and was discharged on June 30.He arrived in Beijing via domestic flight MU5103 on July 1 and was transferred point-to-point from the airport to his residence community in Yanqing District.On July 3,his sample was collected through community mass screening and reported positive in the next morning.The case had received 3 doses of Moderna’s mRNA vaccines in the U.S.,with the last shot on May 26,2022. 展开更多
关键词 AIRPORT TRANSFERRED doses
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Simulation of Haloxylon Ammodendron Stand Basic Diameter Structure Based on Fuzzy Distribution Function
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作者 shaohua wang Chuanqiang Liu Ting Yang 《Agricultural Sciences》 2024年第1期132-145,共14页
Based on the investigation data of 12 Haloxylon ammodendron plots in the south edge of Gurbantunggut Desert, Fuzzy distribution was introduced into the study of Haloxylon ammodendron base diameter structure fitting ac... Based on the investigation data of 12 Haloxylon ammodendron plots in the south edge of Gurbantunggut Desert, Fuzzy distribution was introduced into the study of Haloxylon ammodendron base diameter structure fitting according to the consistency between the characteristics of Fuzzy distribution function and the distribution series of cumulative percentage of stand base diameter, and the fitting precision and effect of Fuzzy distribution function were discussed. The root mean square error RMSE and determination coefficient R<sup>2</sup> values showed that Fuzzy-Γ<sub>1</sub>, Fuzzy-Γ<sub>2</sub>, Fuzzy-Γ<sub>3</sub>, Fuzzy-Γ<sub>4</sub> had good fitting performance, among which Fuzzy-Γ<sub>1</sub> had relatively high fitting precision, and its parameters were closely related to stand age and density, Fuzzy-Γ<sub>2</sub> distribution function was the second, and Fuzzy-Γ<sub>4</sub> distribution function had the worst fitting effect. By introducing a parameter c from the similarity of four distribution function formulas, a generalized Fuzzy distribution function Fuzzy-Γ<sub>5</sub> is obtained. This function shows the highest fitting accuracy. Most of the values of parameter c are near 1 or 2, which shows that the diameter distribution is mainly approximate to Fuzzy-Γ<sub>1</sub> and Fuzzy-Γ<sub>2</sub>. 展开更多
关键词 Fuzzy Distribution Function Haloxylon Ammodendron Base Diameter Distribution Stand Factor
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Research on Adaptive Cluster Sampling Method Based on PPS
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作者 shaohua wang Ting Yang 《Journal of Applied Mathematics and Physics》 2024年第5期1668-1681,共14页
This paper introduces the principle of PPS-based adaptive cluster sampling method and its modified HH estimator and HT estimator calculation method. It compares PPS-based adaptive cluster sampling method with SRS samp... This paper introduces the principle of PPS-based adaptive cluster sampling method and its modified HH estimator and HT estimator calculation method. It compares PPS-based adaptive cluster sampling method with SRS sampling and SRS-based adaptive group. The difference between the group sampling and the advantages and scope of the PPS adaptive cluster sampling method are analyzed. According to the case analysis, the relevant conclusions are drawn: 1) The adaptive cluster sampling method is more accurate than the SRS sampling;2) SRS adaptive The HT estimator of the cluster sampling is more stable than the HH estimator;3) The two estimators of the PPS adaptive cluster sampling method have little difference in the estimation of the population mean, but the HT estimator variance is smaller and more suitable;4) PPS The HH estimator of adaptive cluster sampling is the same as the HH estimator of SRS adaptive cluster sampling, but the variance is larger and unstable. 展开更多
关键词 PPS Adaptive Cluster Sampling Modified HH Estimation Modified HT Estimation
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Effect of Quadrat Shape on Spatial Point Pattern Performance of Haloxylon ammodendron
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作者 shaohua wang Longwei Dai 《Open Journal of Ecology》 2024年第1期66-76,共11页
In this study, we investigated the natural growth of Haloxylon ammodendron forest in Moso Bay, southwest of Gurbantunggut Desert. Random sample analysis was used to analyze the spatial point pattern performance of Hal... In this study, we investigated the natural growth of Haloxylon ammodendron forest in Moso Bay, southwest of Gurbantunggut Desert. Random sample analysis was used to analyze the spatial point pattern performance of Haloxylon ammodendron population. ArcGIS software was used to summarize and analyze the spatial point pattern response of Haloxylon ammodendron population. The results showed that: 1) There were significant differences in the performance of point pattern analysis among different random quadrants. The paired t-test for variance mean ratio showed that the P values were 0.048, 0.004 and 0.301 respectively, indicating that the influence of quadrat shape on the performance of point pattern analysis was significant under the condition of the same optimal quadrat area. 2) The comparative analysis of square shapes shows that circular square is the best, square and regular hexagonal square are the second, and there is no significant difference between square and regular hexagonal square. 3) The number of samples plays a decisive role in spatial point pattern analysis. Insufficient sample size will lead to unstable results. With the increase of the number of samples to more than 120, the V value and P value curves will eventually stabilize. That is, stable spatial point pattern analysis results are closely related to the increase of the number of samples in random sample square analysis. 展开更多
关键词 Spatial Point Pattern Random Quadrat Quadrat Analysis Quadrat Shape
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益生菌辅助治疗骨质疏松患者效果的Meta分析
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作者 冉蕾晶 王绍华 +1 位作者 李林童 桂莉 《昆明医科大学学报》 CAS 2024年第2期65-76,共12页
目的系统评价益生菌治疗骨质疏松的效果。方法计算机检索Cochrane Library、Web of Science、PubMed、Embase、维普网、中国知网、万方数据知识服务平台,检索时限为2023年8月15日,纳入文献为益生菌治疗骨质疏松的随机对照实验。由2位研... 目的系统评价益生菌治疗骨质疏松的效果。方法计算机检索Cochrane Library、Web of Science、PubMed、Embase、维普网、中国知网、万方数据知识服务平台,检索时限为2023年8月15日,纳入文献为益生菌治疗骨质疏松的随机对照实验。由2位研究人员独立筛选文献、提取数据,并评价纳入文献的偏倚风险。采用Stata.14和Revman.5.4软件分析益生菌治疗对患者骨密度、血钙、维生素D、甲状旁腺激素、骨钙素、骨碱性磷酸酶及不良反应的影响。结果最终纳入8篇文献,包括744例研究对象,Meta分析结果显示,在传统药物治疗的基础上加用益生菌,可以增加患者的髋关节骨密度[WMD 0.05(0.01,0.10)]g/cm^(3),增加患者血液中的钙离子浓度[WMD 0.26(0.02,0.50)]mmol/L,增加血液骨钙素的浓度[WMD 1.84(0.60,3.07)]ng/mL,也可以降低骨特异性碱性磷酸酶浓度[SMD-1.06(-2.06,-0.07)],并且可以降低恶心和腹泻的发生率,但对维生素D及甲状旁腺激素的改变,差异无统计学意义(P>0.05)。结论在常规治疗骨质疏松的基础上同时加用益生菌辅助治疗,或可进一步改善患者的骨密度水平,同时降低胃肠道的不良反应,更好的治疗骨质疏松,有利于患者的预后。 展开更多
关键词 益生菌 骨质疏松 骨质疏松症 META分析
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“对分课堂”新模式下的研究型教学实践--以河南理工大学本科高年级化学专业为例 被引量:5
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作者 董喜燕 张会菊 +2 位作者 梅雪澳 王少华 臧双全 《大学化学》 CAS 2021年第7期110-116,共7页
以超分子化学课为载体,基于"生本课堂"教学理念,对教学内容、教学方法和特色实验教学三方面进行教学革新,构建了一套"对分课堂"教学新模式,激励学生进行挑战式学习,锻炼学生的学习能力、资源整合能力和沟通能力,同... 以超分子化学课为载体,基于"生本课堂"教学理念,对教学内容、教学方法和特色实验教学三方面进行教学革新,构建了一套"对分课堂"教学新模式,激励学生进行挑战式学习,锻炼学生的学习能力、资源整合能力和沟通能力,同步提升高年级本科生的素质、能力和知识水平,取得了良好的教学效果。 展开更多
关键词 “对分课堂”教学 挑战式学习 本科高年级 超分子化学课程
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水稻响应缺铁的韧皮部汁液蛋白质组学分析 被引量:4
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作者 陈琳 林焱 +2 位作者 陈鹏飞 王绍华 丁艳锋 《植物学报》 CAS CSCD 北大核心 2019年第2期194-207,共14页
为鉴定水稻(Oryzasativa)响应缺铁的根冠长距离信号转导物质,采用TMT标记技术分析了不同浓度铁处理下水稻韧皮部汁液的蛋白质组学变化,共鉴定出206个差异蛋白,其中54个蛋白表达丰度上调,152个蛋白表达丰度下调。差异蛋白的KEGG通路分类... 为鉴定水稻(Oryzasativa)响应缺铁的根冠长距离信号转导物质,采用TMT标记技术分析了不同浓度铁处理下水稻韧皮部汁液的蛋白质组学变化,共鉴定出206个差异蛋白,其中54个蛋白表达丰度上调,152个蛋白表达丰度下调。差异蛋白的KEGG通路分类主要包括激素信号代谢、谷胱甘肽代谢、碳代谢以及mRNA转运等代谢途径。此外,对差异蛋白对应的生理指标进行测定,发现激素、蔗糖、谷胱甘肽和转运蛋白等在缺铁条件下变化显著,后续对这些差异蛋白的功能研究有助于揭示水稻响应铁素营养的长距离信号途径。 展开更多
关键词 水稻 缺铁 韧皮部 长距离信号 TMT
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加拿大稠油油田油溶性降黏剂的制备及性能评价 被引量:3
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作者 肖洒 孙玉豹 +2 位作者 王少华 吴春洲 舒展 《日用化学工业》 CAS 北大核心 2021年第9期832-838,共7页
加拿大M油田油藏温度低,油藏埋深浅,原油黏度高,含水少,流动性差,针对M油田稠油特性,研制了油溶性降黏剂PH-OV。实验研究表明:油溶性降黏剂PH-OV的较优组成为4%酯化改性聚醚+15%二乙二醇二丁醚+81%芳烃类溶剂油,PH-OV质量分数达到3%时,... 加拿大M油田油藏温度低,油藏埋深浅,原油黏度高,含水少,流动性差,针对M油田稠油特性,研制了油溶性降黏剂PH-OV。实验研究表明:油溶性降黏剂PH-OV的较优组成为4%酯化改性聚醚+15%二乙二醇二丁醚+81%芳烃类溶剂油,PH-OV质量分数达到3%时,对M油田稠油降黏率可达到85.2%;加量达到5%以上时,在14~80℃内的降黏率均可达到80%以上。随着原油含水率的增高,降黏率随之增大,60%含水率时降黏率达到98.5%。该降黏剂可有效降低原油屈服值,对原油降黏性能稳定可达168 h以上,辅助冷水驱油效率可达到30.03%,相比水驱冷采提升了12.86%。油溶性降黏剂PH-OV可适用于M油田稠油冷采,具备有效实施提高采收率的潜力。 展开更多
关键词 稠油 油溶性降黏剂 屈服值 冷采
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Advances on Tumor Image Segmentation Based on Artificial Neural Network 被引量:1
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作者 shaohua wang Jianli Jiang Xiaobing Lu 《Journal of Biosciences and Medicines》 2020年第7期55-62,共8页
Image technology is applied more and more to help doctors to improve the accuracy of tumor diagnosis as well as researchers to study tumor characteristics. Image segmentation technology is an important part of image t... Image technology is applied more and more to help doctors to improve the accuracy of tumor diagnosis as well as researchers to study tumor characteristics. Image segmentation technology is an important part of image treatment. This paper summarizes the advances of image segmentation by using artificial neural network including mainly the BP network and convolutional neural network (CNN). Many CNN models with different structures have been built and successfully used in segmentation of tumor images such as supervised and unsupervised learning CNN. It is shown that the application of artificial network can improve the efficiency and accuracy of segmentation of tumor image. However, some deficiencies of image segmentation by using artificial neural network still exist. For example, new methods should be found to reduce the cost of building the marked data set. New artificial networks with higher efficiency should be built. 展开更多
关键词 Artificial Neural Network Segmentation of Tumor Image Convolutional Neural Network
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Progress of Comprehensive Nursing on the Prevention of Postoperative DVT of Gynecologic Tumor 被引量:1
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作者 shaohua wang Jianli Jiang Xiaobing Lu 《Advances in Reproductive Sciences》 2020年第4期201-208,共8页
Deep vein thrombosis (DVT) is the second reason of death due to tumor. In order to find more effective methods for prevention of DVT due to gynecologic tumor, the advances of study and practice in this aspect should b... Deep vein thrombosis (DVT) is the second reason of death due to tumor. In order to find more effective methods for prevention of DVT due to gynecologic tumor, the advances of study and practice in this aspect should be summarized. As an important and effective measure for prevention of DVT, the comprehensive nursing is to be analyzed carefully. Lots of practices show that proper nursing measures can prevent effectively the occurrence of postoperative DVT. Virchow thought that DVT is caused by three factors: injury of venous wall, slowed blood flow and hypercoagulability. Thus, the prevention measures are presented on the factors such as application of sequential decompression elastic socks, intraoperative intervention etc. Clinical nursing pathway is shown to be very effective method recently. More effective measures and related facilities for prevention of DVT should be built in the future. Physical and psychological methods should be combined in the nursing of DVT. 展开更多
关键词 Deep Vein Thrombosis TUMOR NURSING Prevention of DVT
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Progress on the Study and Practice of Venous Thromboembolism after Operation of Tumor
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作者 shaohua wang Jianli Jiang Xiaobing Lu 《Journal of Biosciences and Medicines》 2020年第8期79-87,共9页
The incidence rate of venous thromboembolism (VTE) of patients after operation is very high. Many studies on VTE have been processed. The pathogenesis, dangerous factors and assessment method of VTE are summarized in ... The incidence rate of venous thromboembolism (VTE) of patients after operation is very high. Many studies on VTE have been processed. The pathogenesis, dangerous factors and assessment method of VTE are summarized in this paper. Two theories of pathogenesis, theory of Virchow’s triad and theory of anoxia at the tip of venous valve, are introduced first. The main dangerous factors of VTE such as tumor, perioperative period are discussed then. The main assessment methods of VTE are introduced also. At last, some problems required to be studied deeper have been presented. 展开更多
关键词 Venous Thromboembolism TUMOR Risk Assessment Score Model
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Advances in the Diagnosis of Breast Tumor by Using Imaging Technology
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作者 shaohua wang Jianli Jiang Xiaobing Lu 《Journal of Biosciences and Medicines》 2020年第10期9-17,共9页
Breast tumor is the most common tumor in the world. The most important method to reduce the mortality due to breast tumor is diagnosed and found as early as possible. Imaging technology is one of the most important me... Breast tumor is the most common tumor in the world. The most important method to reduce the mortality due to breast tumor is diagnosed and found as early as possible. Imaging technology is one of the most important means to help doctors diagnose tumor early. This paper first simply introduces the common imaging technology. Then the mechanism and application of the ultrasonic elastic imaging technology in the diagnosis of breast tumor are summarized and discussed detailly. The methods for image treatment are introduced also. At last the development trend is analyzed. It is shown that the ultrasonic imaging technology is the most convenient and the cheapest relative to other imaging technologies such as nuclear magnetic imaging (NMI) and computer tomography (CT). Especially the ultrasonic elastic imaging technology can provide not only imaging information but also mechanism parameters, which helps to improve the accuracy of diagnosis obviously. Therefore, the ultrasonic elastic imaging technology is worthy of being studied further. More effective image analysis method is required. 展开更多
关键词 Breast Tumor Ultrasonic Elastic Imaging The Method for Image Treatment
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Progress on Therapy of Infertility by Integrated Traditional Chinese and Western Medicine
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作者 shaohua wang Jianli Jiang Xiaobing Lu 《Advances in Reproductive Sciences》 2020年第4期175-185,共11页
Infertility is one of the difficult complicated diseases. Many couples suffer from it. The pathogenesis is very complicated. The imbalance or lesson of any link of the reproductive system can cause infertility. This p... Infertility is one of the difficult complicated diseases. Many couples suffer from it. The pathogenesis is very complicated. The imbalance or lesson of any link of the reproductive system can cause infertility. This paper summarizes the treatment of female infertility by integrated Traditional Chinese Medicine (TCM) and Western Medicine (WM) which can not only improve the ovulation rate and pregnancy rate, but also decrease the complications. The effects are better than that by TCM or WM only. Therefore, the coupling method is worth to be used widely in clinical practice. 展开更多
关键词 INFERTILITY Treatment Integrated Method Traditional Chinese Medicine Western Medicine
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发泡碱式硫酸氧镁胶凝材料的动态力学性能试验研究
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作者 易晓菲 王少华 +3 位作者 张永亮 赵迪 崔晓达 郑志军 《中国科学技术大学学报》 CAS CSCD 北大核心 2022年第4期49-55,I0003,共8页
随着固废再生利用研究的迅速发展,研究固废再生复合材料的性能势在必行。本文对比分析了有无添加固废再生料的发泡碱式硫酸氧镁胶凝材料(FMOCM)的内部结构、准静态和动态力学性能。实验结果表明,由于添加了固废再生料和木粉,FMOCM内部... 随着固废再生利用研究的迅速发展,研究固废再生复合材料的性能势在必行。本文对比分析了有无添加固废再生料的发泡碱式硫酸氧镁胶凝材料(FMOCM)的内部结构、准静态和动态力学性能。实验结果表明,由于添加了固废再生料和木粉,FMOCM内部结构的孔径显著变小,这大幅度提高了FMOCM的准静态抗压强度。同时,FMOCM表现出明显的应变率效应,通过比较动态强度因子可知,常规FMOCM的动态增强效果几乎翻倍,而固废再生料的添加减弱了应变率效应。仅当应变速率较低时,相比于常规FMOCM的粉碎性破坏,含固废再生料的FMOCM表现出较好的韧性。总之,本研究表明固废再生料在轻质碱式硫酸氧镁胶凝材料领域中具有广阔的应用前景。 展开更多
关键词 硫酸氧镁胶凝材料 动态力学性能 应变率效应 固废再生料
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一种适用于非圆形建筑平面的新型球面弦支穹顶结构静力性能研究
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作者 闫翔宇 巩昊 +4 位作者 张起舞 于敬海 陈志华 王少华 王政凯 《钢结构(中英文)》 2021年第4期1-10,共10页
现有球面弦支穹顶结构主要适用于平面投影为标准圆形的建筑,其结构周圈的支座位于同一标高。当建筑要求的平面为多边形或者由多段不同直径圆弧构成的不规则曲线形状时,现有常规的球面弦支穹顶布置形式无法满足该类建筑的需求。为研究球... 现有球面弦支穹顶结构主要适用于平面投影为标准圆形的建筑,其结构周圈的支座位于同一标高。当建筑要求的平面为多边形或者由多段不同直径圆弧构成的不规则曲线形状时,现有常规的球面弦支穹顶布置形式无法满足该类建筑的需求。为研究球面弦支穹顶在平面投影为多边形或多段圆弧构成的非标准圆形建筑中的适用性,介绍了一种新型球面弦支穹顶结构体系,该体系适用于非圆建筑平面,通过采用位于不同标高内的支座将受力性能较好的球面弦支穹顶结构应用到平面投影不规则的建筑中。其平面投影轮廓轴线由八段圆弧组成,长轴尺寸89.89 m,短轴尺寸82.674 m,短轴方向矢高4.104 m,长轴方向矢高4.876 m。上层单层网壳采用K8+联方型网格布置,共设置了五道环索和撑杆。研究了矢跨比、撑杆长度、环索初拉力、环索截面积和支座水平刚度等参数变化对该新型弦支穹顶结构的结构位移、杆件内力和支座反力等静力性能的影响规律。研究结果表明:1)随着短轴矢跨比、撑杆长度、环索初拉力、环索截面积和支座水平刚度的增大,新型球面弦支穹顶结构最大竖向位移减小。2)网壳最大轴力随着撑杆长度、环索初拉力、环索截面积和支座水平刚度的增大而减小,不随短轴矢跨比变化。撑杆内力和环索内力随着短轴矢跨比和支座水平刚度的增大而减小,随着环索初拉力的增大而增大,随着撑杆长度和环索截面积变化复杂。环索节点不平衡力随着短轴矢跨比、撑杆长度和支座水平刚度的增大而减小,随着环索初拉力和环索截面积的增大而增大。3)随着短轴矢跨比增大,支座水平反力基本不变,而支座竖向反力减小;随着撑杆长度和环索截面积的增加,支座水平反力减小,而支座竖向反力增加;随着环索初拉力的增大,支座水平反力、支座竖向反力值减小;随着支座水平刚度 展开更多
关键词 结构工程 新型球面弦支穹顶 静力性能 参数化分析 非圆形建筑平面
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河北省崆山白云洞喀斯特景观保护研究
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作者 李重阳 廖雨竹 +2 位作者 万玉亭 王少华 高璐瑶 《地球科学前沿(汉斯)》 2018年第1期68-79,共12页
河北省临城崆山白云洞发育在以下古生界寒武系为主的碳酸盐岩地层中,是中国北方罕见的大型喀斯特溶洞。洞穴系统平面上呈近南北向延伸的“P”形,洞域面积约32,550 m2,垂向上可分为三层,上层为大型厅堂状,中层和下层为廊道状,各层洞穴以... 河北省临城崆山白云洞发育在以下古生界寒武系为主的碳酸盐岩地层中,是中国北方罕见的大型喀斯特溶洞。洞穴系统平面上呈近南北向延伸的“P”形,洞域面积约32,550 m2,垂向上可分为三层,上层为大型厅堂状,中层和下层为廊道状,各层洞穴以沿陡倾断裂侵蚀、溶蚀而成的通道相连。白云洞拥有形态各异、成因类型多样的喀斯特景观,其中玉簪对宝瓶、五腿神鹿、网状卷曲石、横天一枝等沉积景观、洞顶和洞壁窝穴等侵蚀景观、金钩倒挂等蚀余景观都具有极高的观赏价值和科学研究价值。然而,白云洞自更新世形成至今,曾经历了多次构造运动破坏,而且随着洞穴环境变化以及近年来旅游人数的大幅度增长,洞穴景观损毁日趋严重。洞体岩石破碎、结构稳定性差、洞内景观劣化等问题已较大程度地制约了当地旅游业发展。因此洞穴景观资源保护和洞穴环境治理是当前面临的重要而紧迫的任务。 展开更多
关键词 崆山白云洞 更新世 喀斯特景观 地质地貌环境 旅游资源保护
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不同植被覆盖度对紫色土坡面侵蚀过程的影响 被引量:23
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作者 戴金梅 查轩 +4 位作者 黄少燕 陈世发 翟少华 王丽园 刘川 《水土保持学报》 CSCD 北大核心 2017年第3期33-38,共6页
为研究植被覆盖度对紫色土坡面侵蚀过程的影响,探讨有效控制水土流失的坡面植被临界盖度问题,利用人工模拟降雨试验与室内分析相结合的方法对紫色土坡面侵蚀过程进行分析。结果表明:(1)总体上,紫色土坡面产流量随植被覆盖度的增大而减小... 为研究植被覆盖度对紫色土坡面侵蚀过程的影响,探讨有效控制水土流失的坡面植被临界盖度问题,利用人工模拟降雨试验与室内分析相结合的方法对紫色土坡面侵蚀过程进行分析。结果表明:(1)总体上,紫色土坡面产流量随植被覆盖度的增大而减小,二者之间呈线性负相关,但是植被覆盖度在25%以下,径流量变化不明显,植被覆盖度达75%时,径流量处于较低的稳定值,明显低于植被覆盖度0%,25%,50%;(2)坡面侵蚀泥沙量随植被覆盖度的增加而减少,二者呈二次项相关(R2=0.99),植被覆盖度25%以下对坡面减沙起到重要作用,50%的植被覆盖度是紫色土坡面有效控制水土流失的临界盖度;(3)侵蚀泥沙中以微团聚体(<0.25mm)为主,各级团聚体基本上随着植被覆盖度的增加而呈现减少趋势;(4)通过统计分析,植被覆盖度对产流、产沙量的影响均为极显著(p<0.01)。紫色土坡面植被覆盖度达到50%对涵养水源、保持水土起到至关重要的作用。 展开更多
关键词 紫色土 植被覆盖度 产流量 产沙量 人工模拟降雨
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青海湖流域河流生态系统重金属污染特征与风险评价 被引量:14
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作者 李少华 王学全 +1 位作者 高琪 杨占武 《环境科学研究》 EI CAS CSSCI CSCD 北大核心 2016年第9期1288-1296,共9页
为进一步摸清青海湖流域河流生态系统重金属(Zn、Xu、Pb、Hg、Ni、As、Cd和cr)的污染状况,通过沿青海湖流域主要河流上、中、下游采集河流水体、河岸土壤及河岸植物样品,对样品中的重金属含量进行测定,并分析重金属的来源、污染状... 为进一步摸清青海湖流域河流生态系统重金属(Zn、Xu、Pb、Hg、Ni、As、Cd和cr)的污染状况,通过沿青海湖流域主要河流上、中、下游采集河流水体、河岸土壤及河岸植物样品,对样品中的重金属含量进行测定,并分析重金属的来源、污染状况和潜在生态风险.结果表明:①青海湖流域各介质中重金属从上游到下游均呈明显的累积效应,重金属含量均表现为河岸土壤〉河岸植物〉河流水体.河流下游水体中ρ(Pb)、ρ(Zn)和p(Cd)的平均值分别为11.17、61.22和1.13μg/L,符合GB3838--2002《地表水环境质量标准》中Ⅱ类水质要求;ρ(Hg)为0.06~0.49μg/L,符合GB3838-2002中Ⅱ类或Ⅲ类水质要求.河流下游河岸土壤中ω(As)、ω(cd)和W(Hg)的平均值分别为65.61、0.33和0.20mg/kg,均大幅超过青海湖流域相应环境背景值,但是"(Pb)在下游仅略微超过相应环境背景值.河岸下游植物中ω(Ni)、ω(Cu)、ω(As)和ω(Hg)的平均值分别为2.81、17.35、2.20和0.10mg/kg,均高于《饲料工业标准汇编(下册)(第四版)》中风干草一牧草中重金属标准限值,但在中、上游均符合该标准要求.②Pearson相关分析、主成分分析和富集系数结果表明,河流水体、河岸土壤及河岸植物中Zn、Cu、Ni、Ph、Cr含量之间具有较强的相关性,主要受城镇生活、交通运输及岩石母质风化的影响;Hg、Cd、As含量之间具有较强的相关性,主要受流域旅游交通、农业生产活动和成土母质的影响.③潜在生态风险评价结果显示,河流水体、河岸土壤及河岸植物中Cu、Ni、Cr、Ph和Zn等单一重金属元素的潜在生态风险系数(Er^i)均较低,Hg、Cd和As对综合潜在生态风险指数(RI)的平均贡献率分别为62.9%、18.4%和11.0%,其余5种重金属的平均贡献率仅为7.7%.� 展开更多
关键词 青海湖流域 河岸植物 河流水体 河岸土壤 重金属 污染
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珠江口盆地陆坡类型及其对深水储层的控制 被引量:10
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作者 徐少华 王英民 +5 位作者 何敏 杜家元 徐国强 陈维涛 魏文杰 陈晨 《中国矿业大学学报》 EI CAS CSCD 北大核心 2016年第5期982-992,共11页
为了寻找陆架边缘三角洲和深水扇之间的对应关系,利用三维地震资料解释、沿层属性提取和钻测井信息,探讨珠江口盆地白云凹陷晚渐新世(23.8 Ma)、早中新世(21 Ma)和中中新世(13.8Ma)的陆坡类型和演化.根据陆坡发育侵蚀水道的规模将其分... 为了寻找陆架边缘三角洲和深水扇之间的对应关系,利用三维地震资料解释、沿层属性提取和钻测井信息,探讨珠江口盆地白云凹陷晚渐新世(23.8 Ma)、早中新世(21 Ma)和中中新世(13.8Ma)的陆坡类型和演化.根据陆坡发育侵蚀水道的规模将其分为侵蚀型、侵蚀-加积型和加积型3类.研究结果表明:侵蚀型陆坡(21Ma)发育大规模的下切峡谷,平面上呈顺直-蛇曲型,剖面上为U型或V型的强振幅反射.峡谷内部充填富砂质的碎屑流或浊流沉积,天然堤不发育;峡谷末端发育大型深水扇朵体.侵蚀-加积型陆坡(23.8Ma)发育规模明显小于峡谷的冲沟,与冲沟相连的盆底扇规模减小.加积型陆坡(13.8 Ma)难以识别侵蚀水道.陆坡以粉砂岩和泥岩的披覆沉积为主,低密度浊流或异重流为主要的搬运机制,沉积物在非限制性环境下大多沉积在中—上陆坡区,难以搬运至深水盆地.强烈的构造活动和近物源易于诱发陆坡沉积物的垮塌,是侵蚀型陆坡形成的主要原因.稳定的构造沉降、欠补偿或补偿环境、远离主河口、弱的水动力条件以及海平面持续下降但不低于陆架坡折是加积型陆坡的成因.仅依靠陆架边缘三角洲的发育尚不能对深水储层是否大规模发育做出判断,而伴随海平面持续下降形成的陆坡侵蚀峡谷是深水储层发育的重要保障. 展开更多
关键词 珠江口盆地 白云凹陷 陆架边缘三角洲 陆坡 深水扇
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洗脱液甲状腺球蛋白在甲状腺乳头状癌转移淋巴结中的应用
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作者 徐成 王璐璐 王少华 《中华普外科手术学杂志(电子版)》 2023年第6期701-704,共4页
在甲状腺乳头状癌(PTC)颈部淋巴结(CLN)转移的诊断中,细针穿刺洗脱液甲状腺球蛋白(FNA-Tg)的临床应用获得广泛关注。对于体积较小或囊性变的颈部淋巴结,FNA-Tg诊断颈部转移淋巴结的价值高于超声(US)和细针穿刺细胞学(FNAC)检查。另外,FN... 在甲状腺乳头状癌(PTC)颈部淋巴结(CLN)转移的诊断中,细针穿刺洗脱液甲状腺球蛋白(FNA-Tg)的临床应用获得广泛关注。对于体积较小或囊性变的颈部淋巴结,FNA-Tg诊断颈部转移淋巴结的价值高于超声(US)和细针穿刺细胞学(FNAC)检查。另外,FNA-Tg联合FNAC诊断颈部淋巴结转移的敏感性和特异性接近100%。然而,由于研究中样本差异、检测方法以及试剂盒多样等原因,转移性颈部淋巴结的FNA-Tg的诊断阈值尚未标准化,目前已报道的诊断阈值多在0.2~77 ng/ml之间。FNA-Tg检测的准确性主要受血清抗甲状腺球蛋白抗体水平、血清甲状腺球蛋白水平、甲状腺是否切除以及颈部淋巴结特征等因素影响。本文综述了近年来FNA-Tg在PTC颈淋巴结转移诊断中的应用及研究,为临床PTC颈部淋巴结转移的诊断提供可靠依据。 展开更多
关键词 甲状腺肿瘤 乳头状 细针穿刺洗脱液甲状腺球蛋白 淋巴结转移
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