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NUMERICAL STUDY OF THE PITCHING MOTIONS OF SUPERCAVITA-TING VEHICLES

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Journal of Hydrodynamics 2012年第6期24卷 951-958页

作者： YU Kai-ping ZHANG Guang ZHOU Jing-jun ZOU wang li zhen-wang School of Aeronautics Harbin Institute of Technology

The pitching motions of supercavitating vehicles could not be avoided due to the lost water buoyancy. In order to have some insight for the design of the supercavitating vehicles, the fixed frequency and free pitching motions are investigated. A numerical predicting method based on the relative motion principle and the non-inertia coordinate system is proposed to simulate the free pitching motions of supercavitating vehicles in the longitudinal plane. Homogeneous and two fluid multiphase models are used to predict the natural and the ventilated supercavitating flows. In the fixed frequency pitching motions, a variety of working conditions are considered, including the pitching angular velocities and the supercavity scales and the results are found to be consistent with the available experimental results in literature. The mesh deformation technology controlled by the moment of momentum equation is adopted to study the free pitching motions and finally to obtain the planing states proposed by Savchenko. The numerical method is validated for predicting the pitching motions of supercavitating vehicles and is found to enjoy better calculation efficiency as comparing with the mesh regeneration technology.

关键词： supercavitating flow two fluid multiphase flow model homogeneous model pitching motion mesh deformation

lie Point Symmetry Analysis of the Harry-Dym Type Equation with Riemann-liouville Fractional Derivative

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Acta Mathematicae Applicatae Sinica 2018年第3期34卷 469-477页

作者： li-zhen wang Ding-jiang wang Shou-feng SHEN Qing HUANG Center for Nonlinear Studies Northwest University Xi'an 710069 China Department of Mathematics Northwest University Xi'an 710069 China Department of Applied Mathematics Zhejiang University of Technology Hangzhou 310023 China

In this paper, lie point symmetry group of the Harry-Dym type equation with Riemann-liouville fractional derivative is constructed. Then complete subgroup classification is obtained by means of the optimal system method. Finally, corresponding group-invariant solutions with reduced fractional ordinary differential equations are presented via similarity reductions.

关键词： Harry-Dym equation symmetry group optimal system similarity reduction group-invariantsolution

Spontaneous perforation of an intramural rectal hematoma:Report of a case

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World Journal of Gastroenterology 2012年第19期18卷 2438-2440页

作者： Zhu-lin li zhen-Jun wang Jia-Gang Han Department ofGeneral Surgery Beijing Chaoyang Hospital Capital MedicalUniversity Beijing 100020 China

Spontaneous hematomas are rare and most occur secondary to hematologic disorders or during anticoa- gulant therapy. Most spontaneous hematomas occur above the sigmoid colon, and rarely in the rectum. Herein we present the case of a patient with a spontaneous perforating hematoma of the rectum who presented with severe abdominal pain after a bloody stool. The hemoglobin level decreased by 33 g/L within 20 h. An abdominal sonogram showed a hydrops in the lower abdomen with a maximum depth of 7.0 cm. A hematoma, 8 cm x 6 cmx 5 cm in size, was noted intra-operatively in the rectosigmoid junction, with a 1.5-cm perforation in the hematoma and active hemorrhage. Thus, a partial rectectomy and sigmoidostomy were performed. Three months later, a second opera- tive procedure to re-establish intestinal continuity was performed. The patient is in good condition 12 mo after the last surgery. In addition to this case, the causes of spontaneous perforating hematomas and the treatment are discussed.

关键词： Rectum Hematoma Complications Pro- thrombin time Diagnosis Therapy

Effects of seed aerosols on the growth of secondary organic aerosols from the photooxidation of toluene

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Journal of Environmental Sciences 2007年第6期19卷 704-708页

作者： HAO li-qing wang zhen-ya HUANG Ming-qiang FANG li ZHANG Wei-jun Laboratory of Environmental Spectroscopy Anhui Institute of Optics and Fine Mechanics Chinese Academy of Sciences Hefei 230031 China

Hydroxyl radical （.OH）-initiated photooxidation reaction of toluene was carried out in a self-made smog chamber. Four individual seed aerosols such as ammonium sulfate, ammonium nitrate, sodium silicate and calcium chloride, were introduced into the chamber to assess their influence on the growth of secondary organic aerosols （SOA）. It was found that the low concentration of seed aerosols might lead to high concentration of SOA particles. Seed aerosols would promote rates of SOA formation at the start of the reaction and inhibit its formation rate with prolonging the reaction time. In the case of ca. 9000 pt/cm^3 seed aerosol load, the addition of sodium silicate induced a same effect on the SOA formation as ammonium nitrate. The influence of the four individual seed aerosols on the generation of SOA decreased in the order of calcium chloride〉sodium silicate and ammonium nitrate〉ammonium sulfate.

关键词： toluene photooxidation secondary organic aerosol seed aerosol

Synthesis and Characterization of Chitosan-graft-Poly(lactic acid) Copolymer

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Chinese Journal of Polymer Science 2014年第1期32卷 43-50页

作者：牛旭锋 Feng Tian li-zhen wang Xiao-ming li Gang Zhou 樊瑜波 Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education School of Biological Science and Medical Engineering Beihang University BUAA Research Institute

Chitosan-graft-poly（lactic acid）（CS-g-PLA） copolymer was synthesized through emulsion self-assembly in a water-in-oil （W/O） microemulsion. The water phase was composed of CS aqueous solution, while the oil phase was made up of PLA in chloroform. The W/O microemulsion was fabricated in the presence of surfactant span-80 and the self-assembly was performed between PLA and CS under the effect of N-（3-dimethylaminopropyl）-N＇ethylcarbodiimide hydrochloride （EDC＇HCI）. FTIR and IH-NMR analysis indicated PLA was grafted onto the backbone of CS via the reaction between the carboxyl groups in PLA and the amino groups in CS. 1H-NMR characterization further revealed the grafting content of PLA was 16%. The obtained CS-g-PLA could self-assemble to form micelles, their size distributed in the range of 125-375 nm with average diameter of 142 nm. The present design integrates the favorable biological properties of CS and the excellent mechanical properties of PLA, which makes CS-g-PLA copolymer a promising candidate as a carrier for targeted bioactive molecules delivery.

关键词： Poly(lactic acid) Chitosan Copolymer Self-assembling Grafting.

A New Text Location Approach Based Wavelet

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计算机科学 2002年第Z1期29卷 105-106,114页

作者： Weihua li zhen Fang Shuozhong wang 上海交通大学通信与信息工程学院上海200072 上海交通大学通信与信息工程学院上海200072 上海交通大学通信与信息工程学院上海200072

With the advancement of content-based retrieval technology, the importance of semantics for text information contained in images attracts many researchers. An algorithm which will automatically locate the textual regions in the input image will facilitate the retrieving task, and the optical character recognizer can then be applied to only those regions of the image which contain text. In this paper a new text location method based wavelet is described, which can be used to locate textual regions from complex image and video frame. Experimental results show that the textual regions in image can be located effectively and quickly.

关键词： Text location, 2-D wavelet, Morphological operation

Hypermethylation of thymosinβ4 predicts a poor prognosis for patients with acute-on-chronic hepatitis B liver failure

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Hepatobiliary & Pancreatic Diseases International 2023年第4期22卷 373-382页

作者： He wang Yan-Ping Yin zhen-li wang Yu Qian Yu-Chen Fan Hui-Hui liu Kai wang Department of Hepatology Qilu Hospital of Shandong University#107 Wenhuaxi RoadJinan 250012China Department of Hepatology Qingdao Sixth People’s HospitalQingdao 266000China Department of Gastroenterology Yantaishan HospitalYantai 264000China Institute of Hepatology Shandong UniversityJinan 250012China

Background:It has been demonstrated that thymosinβ4(Tβ4)could inflect the severity of acute-on-chronic hepatitis B liver failure(ACHBLF),but the relationship between its methylation status and the prognosis of liver failure is not *** study aimed to determine Tβ4 promoter methylation status in patients with ACHBLF and to evaluate its prognostic ***:The study recruited 115 patients with ACHBLF,80 with acute-on-chronic hepatitis B pre-liver failure(pre-ACHBLF),and 86 with chronic hepatitis B(CHB).In addition,there were 36 healthy controls(HCs)from the Department of Hepatology,Qilu Hospital of Shandong *** 115 patients with ACHBLF were divided into three subgroups:33 with early stage ACHBLF(E-ACHBLF),42 with mid-stage ACHBLF(M-ACHBLF),and 40 with advanced stage ACHBLF(A-ACHBLF).Tβ4 promoter methylation status in peripheral blood mononuclear cells(PBMCs)was measured by methylation-specific polymerase chain reaction,and mRNA was detected by quantitative real-time polymerase chain ***:Methylation frequency of Tβ4 was significantly higher in patients with ACHBLF than in those with pre-ACHBLF,CHB or ***,expression of Tβ4 mRNA showed the opposite *** patients with ACHBLF,Tβ4 promoter methylation status correlated negatively with mRNA *** 3-month mortality of ACHBLF in the methylated group was significantly higher than that in the unmethylated ***,Tβ4 promoter methylation frequency was lower in survivors than in *** used to predict the 1-,2-,and 3-month incidence of ACHBLF,Tβ4 methylation status was better than the model for end-stage liver disease(MELD)*** predictive value of Tβ4 methylation was higher than that of MELD score for the mortality of patients with E-ACHBLF and M-ACHBLF,but not for ***:Tβ4 methylation might be an important early marker for predicting disease incidence and prognosis in patients with ACHBLF.

关键词： Acute-on-chronic hepatitis B liver failure Acute-on-chronic hepatitis B pre-liver failure Thymosinβ4 Methylation Prognosis

Demethylation of tumor necrosis factor-α converting enzyme promoter associated with high hepatitis B e antigen level in chronic hepatitis B

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World Journal of Gastroenterology 2015年第27期21卷 8382-8388页

作者： zhen-li wang Shuai Gao Xin-You li Feng-Kai Sun Feng li Yu-Chen Fan Kai wang Department of Hepatology Qilu Hospital of Shandong University Institute of Hepatology Shandong University

AIM: To evaluate tumor necrosis factor-α converting enzyme(TACE) methylation status in patients with chronic hepatitis B(CHB).METHODS: Eighty patients with hepatitis B e antigen(HBe Ag)-positive CHB, 80 with HBe Ag-negative CHB, and 40 healthy controls(HCs) were randomly enrolled in this study. Genomic DNA was extracted from peripheral blood mononuclear cells and methylation status of TACE promoter was determined by methylation-specific polymerase chain reaction. The clinical and laboratory parameters were ***: One hundred and thirty of 160 patients with CHB(81.25%) and 38 of 40 HCs(95%) displayed TACE promoter methylation. The difference was significant(χ2 = 4.501, P 0.05). In the HBe Ag-positive group, TACE methylation frequency was significantly negatively correlated with HBe Ag(r =-0.602, P < 0.01), alanine aminotransferase(r =-0.461, P < 0.01) and aspartate aminotransferase(r =-0.329, P < 0.01). CONCLUSION: Patients with HBe Ag-positive CHB have aberrant demethylation of the TACE promoter, which may potentially serve as a biomarker for HBe Ag seroconversion.

关键词： Tumor necrosis factor-α converting enzyme Methylation Chronic hepatitis B Methylation-specificpolymerase chain reaction Biomarker

Analysis and Forecast of the Mortality of Diabetes Mellitus in China

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环境与职业医学 2003年第3期20卷 168-171页

作者： li Rui, wang zhen guo Shanghai Municipal Center for Disease Control and Prevention ShanghaiChina

[目的 ]分析 1990～ 1999年我国城市和农村居民糖尿病死亡率的现况特点并预测未来 5年的变化趋势。 [方法 ]根据《全国卫生统计年报》资料 ,对我国 1990至 1999年糖尿病死亡率的现况进行流行病学分析 ,并利用灰色动态模型GM( 1 1)预测我... 详细信息

[目的 ]分析 1990～ 1999年我国城市和农村居民糖尿病死亡率的现况特点并预测未来 5年的变化趋势。 [方法 ]根据《全国卫生统计年报》资料 ,对我国 1990至 1999年糖尿病死亡率的现况进行流行病学分析 ,并利用灰色动态模型GM( 1 1)预测我国 2 0 0 0至 2 0 0 5年城市和农村糖尿病死亡率趋势。[结果 ]城市 1999年糖尿病死亡率为 15 3 7/ 10万而农村为5 13 / 10万 ,分别是 1990年死亡率的 1 89倍和 1 71倍 ;女性的死亡率高于男性 ,城市和农村男女死亡率之比分别为 0 63∶1和0 76∶1;根据 1990～ 1999死亡率所建立的城市的灰色模型预测方程为 ^Xt=-10 6.4817× ( 1-e0 .0 7458t) -Yt-1(t =1,2 ,...,N) ,而农村的方程为 ^Xt=-3 3 .60 5 3× ( 1-e0 .0 753 7t) -Yt-1(t=1,2 ,...,N) ;预测到 2 0 0 5年我国城市和农村糖尿病死亡率将分别达到 2 5 2 4/ 10万人和 8 15 / 10万人 ;精度检验证明了城市和农村的预测模型拟合良好而外推测值可信。 [结论 ]我国人群糖尿病死亡率上升趋势明显 ,提示有关部门应加强防治力度 ;灰色模型GM( 1 1)能够较好地预测糖尿病死亡率的近期变化趋势。

关键词：糖尿病城市居民农村居民流行病学死亡率灰色模型中国