检索结果-南通市图书馆

A New Robust Risk Measure:Quantile Shortfall

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2020年第9期36卷 1014-1024页

作者： You Li CHEN Yan Yan LIU guang cai mao Yuan Shan WU Fei YAN Law School Wuhan UniversityWuhan 430072P.R.China School of Mathematics and Statistics Wuhan UniversityWuhan 430072P.R.China School of Mathematics and Statistics Central China Normal UniversityWuhan 430079P.R.China School of Statistics and Mathematics Zhongnan University of Economics and LawWuhan 430073P.R.China

Among recent measures for risk management,value at risk(VaR)has been criticized because it is not coherent and expected shortfall(ES)has been criticized because it is not robust to ***,[***.,38,393–417(2013)]proposed a risk measure called median shortfall(MS)which is distributional robust and easy to *** this paper,we propose a more generalized risk measure called quantile shortfall(QS)which includes MS as a special *** measures the conditional quantile loss of the tail risk and inherits the merits of *** construct an estimator of the QS and establish the asymptotic normality behavior of the *** simulation shows that the newly proposed measures compare favorably in robustness with other widely used measures such as ES and VaR.

关键词： Nonparametric estimation quantile shortfall risk measure robust

在线全文

学校读者我要写书评

暂无评论

白鹤灵芝化学成分基础研究

上海中医药杂志 2009年第8期43卷 75-77页

作者：谢丽莎杨广才黄茂春广西中医学院广西南宁530001

目的通过对白鹤灵芝化学成分的分析,建立其成分含量测定的研究基础。方法采用化学鉴别、光谱分析及比色法等方法,对白鹤灵芝的化学成分进行分析及浸出物含量测定。结果白鹤灵芝中可能含有内酯、香豆素类、植物甾醇或三萜类以及酚类、氨... 详细信息

目的通过对白鹤灵芝化学成分的分析,建立其成分含量测定的研究基础。方法采用化学鉴别、光谱分析及比色法等方法,对白鹤灵芝的化学成分进行分析及浸出物含量测定。结果白鹤灵芝中可能含有内酯、香豆素类、植物甾醇或三萜类以及酚类、氨基酸、有机酸、鞣质等成分,无黄酮或黄酮苷类、生物碱等成分。白鹤灵芝药材浸出物含量测定结果,热水浸平均含量为(22.40±2.47)%;冷水浸平均含量为(17.11±2.00)%;冷醇浸平均含量为(2.32±0.32)%;热醇浸平均含量为(5.53±1.12)%。结论白鹤灵芝化学成分的分析与其他成分含量的测定为深入研究白鹤灵芝提供了一定的科学依据。

关键词：白鹤灵芝化学鉴别光谱分析比色法

在线全文

学校读者我要写书评

暂无评论

微晶磨削联合药物治疗轻中度痤疮疗效观察

实用皮肤病学杂志 2011年第1期4卷 22-23,26页

作者：童和林蔡光辉毛辉刘维湖北省黄石市中心医院皮肤科 435000

目的探讨微晶磨削联合药物治疗轻中度痤疮的临床疗效和安全性。方法将160例轻中度痤疮患者随机分成三组,其中治疗组70例,采用微晶磨削联合外用0.025%维A酸乳膏和口服甲硝唑-vitB6片;对照1组40例单独采用微晶磨削治疗;对照2组50例外用0.0... 详细信息

目的探讨微晶磨削联合药物治疗轻中度痤疮的临床疗效和安全性。方法将160例轻中度痤疮患者随机分成三组,其中治疗组70例,采用微晶磨削联合外用0.025%维A酸乳膏和口服甲硝唑-vitB6片;对照1组40例单独采用微晶磨削治疗;对照2组50例外用0.025%维A酸乳膏和口服甲硝唑-vitB6片。8周后观察治疗效果。结果治疗组有效率为100%,对照1组有效率85%,对照2组有效率86%,治疗组有效率明显高于两个对照组,差异分别有统计学意义(P<0.05)。未见明显不良反应。结论微晶磨削联合药物治疗轻中度痤疮较为安全、有效。

关键词：痤疮微晶磨削

The Berry-Esseen bound for identically distributed random variables by Stein method

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 2012年第4期27卷 455-461页

作者： cai guang-hui Department of Mathematics Zhejiang Gongshang UniversityHangzhou 310018China

In this paper, we obtain the Berry-Esseen bound for identically distributed random variables by Stein method. The results obtained generalize the results of Shao and Su （2006） and Stein （1986）.

关键词： Berry-Esseen bound Stein method exchangeable pair.

Dimensionless study on outlet flow characteristics of an air-driven booster

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2012年第6期13卷 481-490页

作者： Yan SHI mao-lin cai School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China

Air-driven boosters are widely used to obtain high-pressure gas. Through analysis of the boosting process of an air-driven booster, the basic mathematical model of working processes can be set up. By selecting the appropriate reference values, the basic mathematical model is transformed to a dimensionless expression. Using MATLAB/Simulink for simulation and studying the booster experimentally, the dimensionless outlet flow characteristics of the booster were obtained and the simulation results agree well with the experimental results. Through analysis, it can be seen that the dimensionless outlet flow of the booster is mainly determined by the dimensionless input pressure of the driving chamber, the dimensionless outlet condition pressure of the booster and the dimensionless area of the piston in the driving chamber. The dimensionless average outlet flow becomes larger with an increasing dimensionless input pressure of the driving chamber, but it becomes smaller with an increase in the dimen- sionless outlet condition pressure of the booster. Especially when the dimensionless outlet condition pressure is approximately 1.4, the dimensionless average outlet flow reaches zero. With an increase in the dimensionless area of the piston in the driving chamber, the dimensionless average outlet flow increases and peaks at approximately 1.89, and after this peak, it starts to decrease. This research can be referred to in the design of air-driven boosters.

关键词： Air-driven booster Outlet flow Pneumatic system Compressed air

Systematic diesel molecular performance evaluation based on quantitative structure-property relationship model

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2022年第2期19卷 809-818页

作者： guang-Qing cai Lin-Zhou Zhang State Key Laboratory of Heavy Oil Processing Petroleum Molecular Engineering Center(PMEC)China University of PetroleumBeijing 102249China

The production and separation of optimal molecules in diesel fuels require a systematic property evaluation for the containing *** paper evaluates the diesel molecules based on four key quality indicators:low-temperature fluidity,cleanliness,ignition,and power *** established the corresponding quantitative structure-property relationship models for corresponding properties,which are freezing point,yield sooting index,cetane number,and combustion *** models were applied for the screening of the high-performance molecules that is suitable for *** molecular performance distribution of the conventional diesel and biodiesel were also ***,we analyzed the effect of different transformation paths on molecular properties,giving guidance on the conversion process design.

关键词： Diesel Optimal molecules QSPR Molecular screening

Experimental study of hydrogen-rich/oxygen-rich gas–gas injectors

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2013年第5期26卷 1164-1172页

作者： Jin Ping Li mao cai Guobiao School of Astronautics Beihang University

Five types of coaxial injectors were investigated experimentally using hot hydrogen-rich gas and oxygen-rich gas, which were respectively provided by a GH2/GO2 hydrogen-rich perburner and a GH2/GO2 oxygen-rich preburner. The injectors were the shear coaxial injector, the oxidizer post expansion coaxial injector, the fuel impinging coaxial injector, the central body coaxial injector, and the shear tri-coaxial injector. The characteristic velocity efficiency and the combustor＇s wall temperatures were obtained for different design parameters through the experiments. It can be con- cluded that angles of the oxidizer post expansion and the fuel impinging have little influence on the combustion performance and the wall temperatures. The contact area between fuel and oxidizer and the mass flow rate have significant impacts on the combustion performance. The shear tri-coaxial injector has the best combustion performance but also the highest wall temperatures among the five types of injectors.

关键词： Combustion performance Experiment Gas-gas injector High mass flow rate Wall temperature

Efect of light response on the photocatalytic activity of BiOClxBr1-x in the removal of Rhodamine B from water

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2013年第11期20卷 1089-1096页

作者： Xiao-ming mao cai-mei Fan College of Chemistry and Chemical Engineering Taiyuan University of Technology

BiOClxBr1-x catalysts were synthesized through an alcoholysis method and characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, high-resolution transmission electron microscopy （HRTEM）, and diffuse reflectance spectroscopy （DRS）. The as-prepared photocatalysts were found to be tetragonal crystal structure and lamellar plate morphology. Their band gaps were between 3.44 and 2.83 eV. The effect of light response on the photocatalytic activity of BiOClxBrl-x was investigated by degradation of Rhodamine B （RhB）. Complete removal of RhB from water was realized under simulated sunlight irradiation for 50 min with BiOC10.5Br0.5. Mechanism studies showed that photo- generated holes and superoxide anion radicals played important roles in RhB photodegradation. The results of chemical oxygen demand （COD） confirmed RhB mineralization. The effect of light response on the activity of BiOClxBr1-x was further investigated under monochromatic light irradiation, and BiOCl0.5Br0.5 catalyst exhibited the highest activity. Furthermore, BiOC10.5Br0.5 exhibited high stability, suggesting its practical application for the removal of RhB pollutant from water.

关键词： photocatalysts photocatalytic activity light response degradation organic pollutants

Full recovery from chronic headache and hypopituitarism caused by lymphocytic hypophysitis:A case report

在线全文

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2022年第3期10卷 1041-1049页

作者： mao-guang Yang Han-Qing cai Si-Si Wang Lin Liu Chun-Mei Wang Department of Endocrinology The Second Hospital of Jilin UniversityChangchun 130000Jilin ProvinceChina Department of Radiology The First Hospital of Jilin UniversityChangchun 130000Jilin ProvinceChina

BACKGROUND Lymphocytic hypophysitis(LYH)is an important condition to consider in the differential diagnosis of patients with a pituitary *** main clinical manifestations of LYH include headache,symptoms related to sellar compression,hypopituitarism,diabetes insipidus and ***,which is a frequent complaint of patients with LYH,is thought to be related to the occupying effect of the pituitary mass and is rapidly resolved with a good outcome after timely and adequate glucocorticoid treatment or *** SUMMARY Here,we report a patient with LYH whose initial symptom was headache and whose pituitary function assessment showed the presence of secondary hypoadrenalism,central hypothyroidism and hypogonadotropic *** magnetic resonance imaging showed symmetrical enlargement of the pituitary gland with suprasellar extension in a dumbbell shape with significant homogeneous enhancement after gadolinium *** size of the gland was approximately 17.7 mm×14.3 mm×13.8 *** pituitary stalk was thickened without deviation,and there was an elevation of the optimal *** lesion grew bilaterally toward the cavernous sinuses,and the parasternal dural caudal sign was *** patient presented with repeatedly worsening and prolonged headaches three times even though the hypopituitarism had fully resolved after glucocorticoid treatment during this *** This rare headache regression suggests that patients with chronic headaches should also be alerted to the possibility of LYH.

关键词： Lymphocytic hypophysitis Magnetic resonance imaging Hypopituitarism Headache Glucocorticoid Case report