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CPPI投资组合保险策略的实证分析 被引量:15
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作者 杜少剑 陈伟忠 +3 位作者 du Shao-jian CHEN Wei-zhong 《财贸研究》 北大核心 2005年第1期36-40,共5页
本文首先简要介绍了CPPI投资组合保险策略,通过采用上证综合指数,对多头、空头和震荡三个时期,以及不同的最低保险额和乘数,对CPPI策略进行历史数据实证模拟,并与B&H策略做比较,发现CPPI策略在我国证券市场是能够起到有效保险作用的.
关键词 保险 投资组合 策略 低保 上证综合指数 证券市场 实证分析 乘数 时期 中国
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Use of Probiotics in Aquaculture 被引量:6
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作者 王祥红 du +8 位作者 Zongjun Chen Jixiang Li Yun Ji Weishang Xu Huaishu 《High Technology Letters》 EI CAS 2002年第3期22-27,共6页
Diseases of cultured animal and environmental pollution are very important problems in aquaculture. The use of probiotics in aquaculture has more advantages than the use of antibiotics and chemicals in aquaculture. Th... Diseases of cultured animal and environmental pollution are very important problems in aquaculture. The use of probiotics in aquaculture has more advantages than the use of antibiotics and chemicals in aquaculture. This review introduces the use and mechanisms of the probiotics in aquaculture. 展开更多
关键词 水养殖技术 环境污染 细菌应用
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Multi-scale analysis of earthquake activity in Chinese mainland 被引量:1
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作者 SHAO Hui-cheng(邵辉成) +7 位作者 du Chang-e(杜长娥) LIU Zhi-hui(刘志辉) SUN Yan-xue(孙彦雪) XIA Chang-qi(夏长起) 《Acta Seismologica Sinica(English Edition)》 CSCD 2004年第1期109-113,共5页
Identifying the active and inactive period of earthquakes in Chinese mainland is of great importance for guiding mid-short term, especially short term, earthquake forecast.……
关键词 multi-scale analysis wavelet analysis Chinese mainland
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The Effects of Shrimp Gut Probiotic Bacteria on the Shrimp Larvae (Penaeus Chinensis) 被引量:1
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作者 王祥红 du +8 位作者 Zongjun Li Huirong Li Yun Ji Weishang Xu Huaishu 《High Technology Letters》 EI CAS 2002年第4期7-12,共6页
The survival rates of shrimp larvae in different stage are higher than those of control groups when probiotic bacteria strains X4B 1 and X1B 1 which are isolated from gut of adult shrimp are added into the little volu... The survival rates of shrimp larvae in different stage are higher than those of control groups when probiotic bacteria strains X4B 1 and X1B 1 which are isolated from gut of adult shrimp are added into the little volume rearing sea water of shrimp larvae. The effects of probiotic bacteria are evaluated by challenge test (pathogenic bacteria Z 3G 2 isolated from disease shrimp larvae in the hatchery of Jimo town) and low salinity stress resistance tests on shrimp larvae, the survival rate and lengths of the shrimp larvae in the experiment are determined. Results indicate that 1. The survival rate, ability of resistant to low salinity, lengths of the delivered shrimp larvae are improved after the strains of probiotic bacteria, X4B 1 or X1B 1, are added into the rearing sea water of hatchery. 2. The addition of the probiotic bacteria could not influence the change of the bacteria number, NH3 N and COD value in the rearing sea water. 3. The probiotic bacteria used in the experiment have many enzymes such as Lipase, Amylase, Gelatinase and Lecithinase. These enzymes may help the probiotic bacteria to digest the food components fed to shrimp larvae and increase the digestive efficiency of post larvae. This may be one of the reasons why these probiotic bacteria are beneficial to the shrimp larvae. 展开更多
关键词 PENAEUS chinensis gut of shrimp shrimp larvae probiotic BACTERIA
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土壤中总石油烃(C10-C40)的测定超声萃取-气相色谱法的方法研究 被引量:1
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作者 蔡言 贾长城 +3 位作者 郭艳梅 林佳琦 刁雪松 杜朋 《城市地质》 2020年第4期462-467,共6页
通过对比3种溶剂体系,正己烷,正己烷/丙酮1∶1,正己烷/二氯甲烷1∶1萃取土壤样品中的总石油烃,发现正己烷/丙酮1∶1的溶剂体系回收率显著高于其他两种体系。加速溶剂萃取与超声萃取方法比较,回收率基本保持在一个水平上,超声萃取所用耗... 通过对比3种溶剂体系,正己烷,正己烷/丙酮1∶1,正己烷/二氯甲烷1∶1萃取土壤样品中的总石油烃,发现正己烷/丙酮1∶1的溶剂体系回收率显著高于其他两种体系。加速溶剂萃取与超声萃取方法比较,回收率基本保持在一个水平上,超声萃取所用耗材少,操作简单,更适合于批量化生产,通过洁净度实验选择最佳的清洗方法。结果表明:该方法能够满足土壤中总石油烃的分析要求,前处理程序简单快速,分析重复性好,检测结果高效准确,对生产型实验室大批量石油烃样品的测定具有显著优势。该方法已应用于北京某地区上千件土壤样品石油烃的测定,得到了高质量的检测数据。 展开更多
关键词 总石油烃 土壤 超声萃取 气相色谱法
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DISSIPATIVE SCHEMES WITH PROPERTY OF INHERITING HOMOCLINIC ORBITS FOR 2N-DIMENSIONAL HAMILTONIAN SYSTEMS
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作者 du Weihua(杜维华) +1 位作者 Huang Mingyou(黄明游) 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 2002年第2期197-212,共16页
In this paper we develop a kind of dissipative discrete scheme for the computation of homoclinic orbits near TB-point in Hamiltonian systems. It is proved by using continuation method that when the dissipative term an... In this paper we develop a kind of dissipative discrete scheme for the computation of homoclinic orbits near TB-point in Hamiltonian systems. It is proved by using continuation method that when the dissipative term and its coefficient are suitably chosen, this scheme possesses discrete homoclinic orbits, which approximate the continuous homoclinic orbits with second order accuracy w.r. to time-step size. 展开更多
关键词 HAMILTONIAN system HOMOCLINIC orbit DISSIPATIVE scheme CONTINUATION method.
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EFFECTIVE SHIELDING OF UNIDIRECTIONAL CURRENT GENERATED MAGNETIC FIELDS
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作者 XU Lin(徐霖) +3 位作者 FU Zheng-cai(傅正财) du Ya-ping(杜亚平) 《Journal of Shanghai Jiaotong university(Science)》 EI 2002年第2期171-174,共4页
This paper presented an effective shielding design of magnetic fields generated by unidirectional current. Theoretical formulas and numerical computation software based on boundary element method (BEM) are employed to... This paper presented an effective shielding design of magnetic fields generated by unidirectional current. Theoretical formulas and numerical computation software based on boundary element method (BEM) are employed to evaluate the shielding effectiveness (SE) of cylindrical shell. It is shown that ungrounded or one end grounded metal shell is ineffective for such magnetic fields. SE can be obtained by connecting the two ends of the conducting shell with low impedance connector, or alternatively, grounding the two ends. The experimental results also support these conclusions. 展开更多
关键词 magnetic SHIELDING CYLINDRICAL shell boundary element method EDDY CURRENT
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Error compensation for precision machine tools
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作者 LU Zesheng(卢泽生) +3 位作者 ZHENG Dezhi(郑德志) du Jinming(杜金名) 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2002年第3期282-287,共6页
As one of the ways to improve the machining accuracy of machine tools, error compensation is reviewed from different view points, and the main barriers to further improvement of efficiency of error compensation are an... As one of the ways to improve the machining accuracy of machine tools, error compensation is reviewed from different view points, and the main barriers to further improvement of efficiency of error compensation are analyzed in detail and the vista of the error compensation in precision and ultra precision machines is discussed. 展开更多
关键词 ERROR COMPENSATION MACHINING ACCURACY PRECISION MACHINE tool
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Study of Rat Osteoblasts Transfected by Transforming Growth Factor β_1 Gene
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作者 LIU Yong(刘勇) +11 位作者 du Jingyuan(杜靖远) ZHENG Qixin(郑启新) WANG Hong(王洪) GUO Xiaodong(郭晓东) duAN Deyu(段德宇) LIU Weigang(刘维钢) 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2002年第2期116-117,143,共3页
Summary: In order to investigate the effect of TGFβ 1 gene transfer on the biological characteristics, the effects of gene transfer and supernatant of transfected osteoblasts on the proliferation and ALP activity of... Summary: In order to investigate the effect of TGFβ 1 gene transfer on the biological characteristics, the effects of gene transfer and supernatant of transfected osteoblasts on the proliferation and ALP activity of osteoblasts were detected by 3H-TdR and MTT. Our results showed that TGFβ 1 gene transfer had no effect on the biological characteristics and the activated supernatant of transfected osteoblasts stimulated proliferation and inhibited ALP activity of osteoblasts. TGFβ 1 gene transfer could promote the expression of TGFβ 1 and the biological characteristics of transfected osteoblasts were stable, which might be helpful for gene therapy of bone defects in vivo. 展开更多
关键词 transforming growth factor β 1 OSTEOBLASTS gene transfer
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Influence of particle structure on electrochemical character of composite graphite
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作者 Cuiwei du +2 位作者 Yujuan Zhao 《Journal of University of Science and Technology Beijing》 CSCD 2003年第1期61-64,共4页
The natural graphite has been used as the anode material for Lithium-Ion batteries, because of its low cost, chemical stability and excellent reversibility for Li+ insertion. However, the slow diffusion rate of lithiu... The natural graphite has been used as the anode material for Lithium-Ion batteries, because of its low cost, chemical stability and excellent reversibility for Li+ insertion. However, the slow diffusion rate of lithium ion and poor compatibility with electrolyte solutions make it difficult to use in some conditions. In order to solve these problems, an epoxy-coke/graphite composite has been manufactured. The particle of composite carbonaceous material coated on non-graphitizable (hard) carbon matrix. Due to the disordered structure, the diffusion rate of lithium species in the non-graphitzable carbon is remarkably fast and less anisotropic. The process for preparing a composite carbon powder provides a promising new anode material with superior electrochemical properties for Li-ion batteries. The unique structure of epoxy-coke/graphite composite electrodes results in much better kinetics, also better recharge ability and initial charge/discharge efficiency. 展开更多
关键词 lithium-ion batteries negative materials natural graphite structure model
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Mining Rules from Electrical Load Time Series Data Set
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作者 郑斌祥 Xi +4 位作者 Yugen du Xiuhua Li Shaoyuan 《High Technology Letters》 EI CAS 2002年第1期41-45,共5页
The mining of the rules from the electrical load time series data which are collected from the EMS (Energy Management System) is discussed. The data from the EMS are too huge and sophisticated to be understood and use... The mining of the rules from the electrical load time series data which are collected from the EMS (Energy Management System) is discussed. The data from the EMS are too huge and sophisticated to be understood and used by the power system engineer, while useful information is hidden in the electrical load data. The authors discuss the use of fuzzy linguistic summary as data mining method to induce the rules from the electrical load time series. The data preprocessing techniques are also discussed in the paper. 展开更多
关键词 电力工业 电负荷 时序数据 数据预处理技术
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爱要爱一种温暖的
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作者 星烨 Villa +1 位作者 du Laca(图) 《设计》 2005年第11期134-135,共2页
Jan的ice cube设计,就像他经常提起的,如果在一杯水的杯底放上“爱”字,水的结晶就会变得美好,他在冰块里冰封了一棵樱桃或一枚糖果的甜蜜,有时候,是有机蔬菜的清新。
关键词 温暖 有机蔬菜 ICE CUBE 冰块 樱桃
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AN IDYLLIC VIEW FROM THE ISLAND IN THE YAMDROK LAKE
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作者 Chen du +1 位作者 Fan Jinhui(图) 《China's Tibet》 2011年第4期20-29,共10页
COMING TO THE ISLAND The boat edged forward through shining waves under the strong sunlight.Gradually,the wind increased and snow began to fall.Seemingly,the boat was penetrating a narrow straight formed by the fallin... COMING TO THE ISLAND The boat edged forward through shining waves under the strong sunlight.Gradually,the wind increased and snow began to fall.Seemingly,the boat was penetrating a narrow straight formed by the falling snow and located between Gongbo Shod and Serdor Island.Little by little,Serdor Village appeared before us,lying on a yellow mountain valley.Maybe because of the very cold weather,there was nobody 展开更多
关键词 课外阅读 文学 英语阅读 优秀文章
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新辅助化疗联合间歇性肿瘤细胞减灭治疗晚期卵巢癌的效果及总生存期的影响因素分析 被引量:7
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作者 陈会晓 张凤丽 +3 位作者 刘雪崴 杜静 王斌 庄献鹏 《中国实用医刊》 2018年第12期50-53,56,共5页
目的探讨新辅助化疗联合间歇性肿瘤细胞减灭术对晚期卵巢癌患者的治疗效果,评估影响患者总生存期的危险因素。方法回顾分析2009年6月至2015年12月来医院就诊的晚期卵巢癌患者423例的临床资料,根据治疗方式不同分为对照组(初次肿瘤细... 目的探讨新辅助化疗联合间歇性肿瘤细胞减灭术对晚期卵巢癌患者的治疗效果,评估影响患者总生存期的危险因素。方法回顾分析2009年6月至2015年12月来医院就诊的晚期卵巢癌患者423例的临床资料,根据治疗方式不同分为对照组(初次肿瘤细胞减灭术联合化疗,PDS组)228例和观察组(新辅助化疗联合间歇性肿瘤细胞减灭术,IDS组)195例。比较两组患者的一般情况、手术情况、疗效及总生存期(OS)和无进展生存期(PFS)。采用多因素分析方法探讨影响晚期卵巢癌患者预后的独立危险因素。结果(1)IDS组患者的满意缩瘤率(72.82%)明显高于PDS组患者(60.96%,P〈0.05),IDS组无肉眼残留病灶的比例(7.18%)也明显大于PDS组(3.95%,P〈0.05)。(2)IDS组患者手术时间、术中出血量及输血量、术后住院时间明显少于PDS组患者(P〈0.05)。(3)IDS组患者治疗总有效率(62.05%)明显高于PDS组患者(49.56%,P〈0.05)。(4)IDS组患者PFS和OS均长于PDS组,但差异未见统计学意义(P〉0.05)。(5)FIGO分期Ⅲ~Ⅳ期、病理G2级、最大肿瘤直径〉10cm及残余肿瘤直径〈1cm是影响患者预后的独立危险因素(P〈0.05)。结论新辅助化疗联合间歇性肿瘤细胞减灭术能够明显提高晚期卵巢癌治疗的满意缩瘤率,减少手术时间、术中出血量及输血量,提高治疗有效率,但是不能提高患者的PFS和OS。患者的临床分期、病理分级、最大原发肿瘤直径和残余瘤体积可能对患者选择治疗方案提供帮助。 展开更多
关键词 新辅助化疗 肿瘤细胞减灭术 卵巢癌
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Point-of-care Ultrasound as a Useful Tool for Assessment of Undifferentiated Dyspnea in Rapid Response Team Consultation
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作者 du Jiang +7 位作者 Lin Qiuhai Xie Hui Zhou Zhigang Wang Ruilan 《中华肺部疾病杂志(电子版)》 CAS 2018年第3期318-325,共8页
Objective The purpose of this study is to evaluate the role of point-of-care ultrasound( POCUS) in assessm ent of patients with dyspnea in Rapid Response Team( RRT)consultation. 53 patients were included and their pre... Objective The purpose of this study is to evaluate the role of point-of-care ultrasound( POCUS) in assessm ent of patients with dyspnea in Rapid Response Team( RRT)consultation. 53 patients were included and their pre-POCUS, post-POCUS and final diagnoses were docum ented. Com pared with pre-POCUS diagnoses,the accuracy of postPOCUS diagnoses increased significantly from 37.7% up to 79.2%,P<0.01( final diagnoses as golden standard). When stratified by etiology, we can see that POCUS im proved the diagnostic sensitivity and specificity in m ost of the diseases. But still there were 11 patients in whom POCUS fail to diagnose. And in those POCUS-fail group the m ortality seem ed higher than in POCUS achieved group. In conclusion POCUS is a convenient and useful diagnostic tool which can im prove the diagnostic accuracy of patients with sudden onset of dyspnea in RRT consultation. 展开更多
关键词 POINT-OF-CARE ULTRASOUND Rapid Response Team Critical Care DYSPNEA ADVERSE Event
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亘古神话-恐龙鱼
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作者 fisher du du(图) 《中国观赏鱼》 2007年第1期12-19,共8页
不管我们以何种理由迷恋上了恐龙,也不管我们用何种方式表达对“她”的钟爱,我们的目的只有一个,那就是将这种狂热发挥到极致。
关键词 恐龙鱼 热带鱼 生活习性 物种
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