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1Prevalence of Nontraumatic Osteonecrosis of the Femoral Head and its Associated Risk Factors in the Chinese Population: Results from a Nationally Representative Survey显示文摘De-Wei Zhao Mang Yu Kai Hu Wei Wang Lei Yang Ben-Jie Wang Xiao-Hong Gao Yong-Ming Guo Yong-Qing Xu Yu-Shan Wei Si-Miao Tian Fan Yang Nan Wang Shi-Bo Huang Hui Xie Xiao-Wei Wei Hai-Shen Jiang Yu-Qiang Zang Jun Ai Yuan-Liang Chen Guang-Hua Lei Yu-Jin Li Geng Tia Zong-Sheng Li Yong Cao Li Ma 2015Chinese Medical Journal2015,,21:151
2The Association of Maternal Body Composition and Dietary Intake with the Risk of Gestational Diabetes Mellitus during the Second Trimester in a Cohort of Chinese Pregnant Women显示文摘Objective To investigate the association of maternal body composition and dietary intake with the risk of gestational diabetes mellitus(GDM). Methods A total 154 GDM subjects and 981 controls were enrolled in a prospective cohort study in 11 hospitals from May 20, 2012 to December 31, 2013. Bioelectrical impedance analysis and dietary surveys were used to determine body composition and to evaluate the intake of nutrients in subjects at 21-24 weeks' gestation(WG). Logistic regression analysis was applied to explore the relationships of maternal body composition and dietary intake with the risk of GDM morbidity. Results Age, pre-pregnant body weight(BW), and body mass index(BMI) were associated with increased risk of GDM. Fat mass(FM), fat mass percentage(FMP), extracellular water(ECW), BMI, BW, energy, protein, fat, and carbohydrates at 21-24 WG were associated with an increased risk of GDM. In contrast, fat free mass(FFM), muscular mass(MM), and intracellular water(ICW) were associated with a decreased risk of GDM. Conclusion Maternal body composition and dietary intake during the second trimester of pregnancy were associated with the risk of GDM morbidity.Xu Qing Gao Zhi Ying Li Li Ming Wang Lu Zhang Qian Teng Yue Zhao Xia Ge Sheng Jing Hong Jiang Yang Yong Tao Liu Xiao Jun Lyu Chun Jian Mao Lun Yu Xiao Ming Liu Ying Hua Kong Ai Jing Yang Xue Yan Liu Zhao Zhang Yong Wang Jin Zhang Xin Sheng Xue Chang Yong Lu Yan Ping 2016Biomedical and Environmental Sciences2016,29,1:29
3Neighbor Sum Distinguishing Total Colorings of Graphs with Bounded Maximum Average Degree显示文摘A proper [h]-total coloring c of a graph G is a proper total coloring c of G using colors of the set [h]={1,2,...,h}.Letw(u) denote the sum of the color on a vertex u and colors on all the edges incident to u.For each edge uv∈E(G),if w(u)≠w(v),then we say the coloring c distinguishes adjacent vertices by sum and call it a neighbor sum distinguishing [h]-total coloring of G.By tndi(G),we denote the smallest value h in such a coloring of G.In this paper,we obtain that G is a graph with at least two vertices,if mad(G)<3,then tndi∑(G)≤k+2 where k=max{Δ(G),5}.It partially con?rms the conjecture proposed by Pil′sniak and Wozniak.Ai Jun DONG Guang Hui WANG 2014Acta Mathematica Sinica,English Series2014,30,4:24
4Report on Childhood Obesity in China (9): Sugar-sweetened Beverages Consumption and Obesity显示文摘Objective To explore the associations between sugar-sweetened beverage (SSB) consumption and obesity as well as obesity-related cardiometabolic disorders among children in China. Methods A total of 6974 (boys 3558, girls 3412) children aged 6-13 years participated in the study. Each participant's height, weight, waist circumference, fasting glucose, triglycerides, total cholesterol, high- density lipoprotein cholesterol, and low-density lipoprotein cholesterol were measured. The type of beverage consumption was determined using a self-administered questionnaire. Results SSBs were consumed regularly by 46.1% of the children. The prevalence [adjusted odds ratio (95% confidence internal (CI)] of obesity was 7.6% [as the reference group (ref.)], 10.1% [1.36(1.07, 1.74)], and 11.6% [1.46(1.21, 1.75)], among children who regularly drank milk, other beverages and SSBs, respectively. Regularly drinking SSBs elevated the likelihood of abdominal obesity [adjusted odds ratio (95% CI): 1.36 (1.17, 1.59)]. The prevalence [adjusted odds ratio (95% CI)] of obesity among children who regularly drank sports/caloric beverages, carbonated beverages, sweet tea, and plant protein beverages was 16.8% [2.00(1.31, 3.07)], 12.7% [1.52(1.23, 1.88)], 11.5% [1.52(1.18, 1.95)], and 10.4% [1.41(1.03, 1.94)], respectively, which was higher than that of regular milk drinkers [7.6 % (ref.)]. The prevalence [adjusted odds ratio (95% CI)] of abdominal obesity among children who regularly drank sweet tea, fruit/vegetable juices, and carbonated beverages was 17.7% [1.55(1.26, 1.90)], 16.2% [1.36(1.09, 1.70)], and 15.3% [1.24(1.03, 1.50)], respectively, which was much higher than that of regular milk drinkers [12.8% (ref.)]. Conclusions Regular SSB consumption was positively related to obesity and abdominal obesity. This relationship should be investigated further using a longitudinal study design.SHANG Xian Wen LIU Ai Ling ZHANG Qian HU Xiao Qi DU Song Ming MA Jun XU Gui Fa LI Ying GUO Hong Wei DU Lin LI Ting Yu MA Guan Sheng 2012Biomedical and Environmental Sciences2012,25,2:23
5Expression of regulating apoptosis gene and apoptosis index in primary liver cancer显示文摘INTRODUCTIONProgramed cell death plays an important role in thegenesis of cancer.Certain cancer genes canregulate apoptosis.Recently,several proteins thatare structurally related to Bcl-2,an inhibitor ofapoptosis,have been identified.Therefore,novel strategies and agents that target specificmolecular pathways,as well as triggering aHong Yu Xu You Lin Yang Xi Li Guan Guang Song Ai Min Jiang Li Jun Shi 2000World Journal of Gastroenterology2000,6,5:21
6Kinetics and corrosion products of aqueous nitrate reduction by iron powder without reaction conditions control显示文摘Although considerable research has been conducted on nitrate reduction by zero-valent iron powder (Fe0), these studies were mostly operated under anaerobic conditions with invariable pH that was unsuitable for practical application. Without reaction conditions (dissolved oxygen or reaction pH) control, this work aimed at subjecting the kinetics of denitrification by microscale Fe0 (160–200 mesh) to analysis the factors affecting the denitrification of nitrate and the composition of iron reductive products coating upon the iron surface. Results of the kinetics study have indicated that a higher initial concentration of nitrate would yield a greater reaction rate constant. The reduction rate of nitrate increased with increasing Fe0 dosage. The reaction can be described as a pseudo-first order reaction with respect to nitrate concentration or Fe0 dosage. Experimental results also suggested that nitrate reduction by microscale Fe0 without reaction condition control primarily was an acid-driven surface-mediated process, and the reaction order was 0.65 with respect to hydrogen ion concentration. The analyses of X-ray diffractometry and X-ray photoelectron spectroscopy indicated that a black coating, consisted of Fe2O3, Fe3O4 and FeO(OH), was formed on the surface of iron grains as an iron corrosion product when the system initial pH was lower than 5. The proportion of FeO(OH) increased as reaction time went on, whereas the proportion of Fe3O4 decreased.FAN Xiaomeng GUAN Xiaohong MA Jun AI Hengyu 2009Journal of Environmental Sciences2009,21,8:17
7A Cross-sectional Survey Assessing Carriage of Streptococcus pneumoniae in a Healthy Population in Xinjiang Uygur Autonomous Region of China显示文摘链球菌 pneumoniae 的车厢率和 serotype 分发(S。pneumoniae ) 在在中国遗体的一张健康人口不清楚。在这研究,我们在 Xinjiang 从 513 个个人收集了 oropharyngeal 拖把,中国。指向 lytA 基因和 12 serotypes 的实时 PCR 被估计识别 S。pneumoniae 马车。S 的全部的车厢率。pneumoniae 是 70.4%(361/513 ) 。最流行的 serotypes 是 19B/F, 18B/C, 5,并且 6A/B。S 的最高的车厢率。pneumoniae 6-10 年(88.6%) 在孩子被注意,它应得进一步的注意。二的合作殖民率或更多的 S。pneumoniae serotypes 是 79.8%(264/331 ) 。这研究试图在中国在健康个人之中调查基线 pneumococcal 马车率改进我们 S 的传染病学的理解。pneumoniae。XIE Na CHEN Zhao Yun CHEN Tao ZHU Bing Qing XU Li GAO Yuan ZHANG Ai Yu ZHAO Pan LIU Ji Wen SHAO Zhu Jun 2018Biomedical and Environmental Sciences2018,31,3:15
8Estrogen reduces CCL_4-induced liver fibrosis in rats显示文摘AIM: Chronic liver diseases, such as fibrosis or cirrhosis,are more common in men than in women. This genderdifference may be related to the effects of sex hormones onthe liver. The aim of the present work was to investigatethe effects of estrogen on CCL4-induced fibrosis of the liverin rats.METHODS: Liver fibrosis was induced in male, female andovariectomized rats by CCL4 administration. All the groupswere treated with estradiol(1 mg/kg) twice weekly. Andtamoxifen wasgiven to male fibrosis model. At the end of 8weeks, all therats were killed to study serum indicators andthe livers.RESULTS: Estradiol treatment reduced aspartateaminotransferase(AST), alanine aminotransferase (ALT),hyaluronic acid(HA) and type IV collagen(CIV) in sera,suppressed hepatic collagen content, decreased the areas ofhepatic stellate cells (HSC) positive for α-smooth muscle actin(α-SMA), and lowered the synthesis of hepatic type I collagensignificantly in both sexes and ovariectomy fibrotic rats inducedby CCL4 administration. Whereas, tamoxifen had the oppositeeffect. The fibrotic response of the female liver to CCL4treatment was significantly weaker than that of male liver.CONCLUSION: Estradiol reduces CCL4-induced hepaticfibrosis in rats. The antifibrogenic role of estrogen in theliver may be one reason for the sex associated differencesin the progression from hepatic fibrosis to cirrhosis.Jun-Wang Xu Jun Gong Xin-Ming Chang Jin-Yan Luo Lei Dong Zhi-Ming Hao Ai Jia Gui-Ping Xu 2002World Journal of Gastroenterology2002,8,5:14
9The role of Med19 in the proliferation and tumorigenesis of human hepatocellular carcinoma cells显示文摘Shao-wu ZOU Kai-xing AI Zhi-gang WANG Zhou YUAN Jun YAN Qi ZHENG 2011Acta Pharmacologica Sinica2011,32,3:12
10Water relations and an expression analysis of plasma membrane intrinsic proteins in sensitive and tolerant rice during chilling and recovery显示文摘寒心的损害的症状是在射击的水赤字的开发,源于水运输和蒸发的不平衡。在这个工作,二个米饭变化(Oryza sativa L。var。Wasetoitsu 和 Somewake ) 幼苗是在 7 度 C 的 chilled,在 28 度 C 由恢复列在后面。基于生长显型和电解质漏测试, Somewake 被显示是一个寒心容忍的变化,和 Wasetoitsu 寒心敏感的。寒心的压力显著地减少了叶子,积聚的蒸发和渗透的根的相对的水内容(RWC ) 在两个变化的水力的电导率(Lp ) 。但是当回到了 28 度 C 时, Somewake 的水关系平衡更好恢复了。所有 11 血浆膜的 mRNA 表示侧面内在的蛋白质(果仁) , aquaporins 的亚群,被有 TaqMan 次要的林子文件夹(MGB ) 的 -PCR 探查的即时反向的抄写(RT ) 随后决定源于米饭 var。Nipponbare 在寒心的处理和恢复期间。大多数 PIP 基因在低温度是下面调整的,并且在温暖的温度恢复了。在 Somewake 和 Wasetoitsu 的一些果仁的相对表示在平行减少了在期间寒心。然而在恢复期间, OsPIP1 的相对表示; 1, OsPIP2; 1, OsPIP2; 7 在射击和 OsPIP1; 1, OsPIP2; 1 比 Wasetoitsu 在 Somewake 在根是显著地更高的。这在在寒心的条件以后重建水平衡支持果仁的角色。我们讨论 aquaporin 果仁亚科的成员在植物起的多样化的作用寒心的忍耐取决于 aquaporin isoforms,植物织物和寒心的持续时间的阶段。Xin Yu Yan Hui Peng Min Hua Zhang Yan Jun Shao Wei Ai Su Zhang Cheng Tang 2006Cell Research2006,16,6:11
11Preparation of Li_4Ti_5O_(12) submicrospheres and their application as anode materials of rechargeable lithium-ion batteries显示文摘We report on the preparation of spinel Li4Ti5O12 submicrospheres and their application as anode materials of rechargeable lithium-ion batteries. The spinel Li4Ti5O12 submicrospheres are synthesized with three steps of the hydrolysis of TiCl4 to form rutile TiO2, the hydrothermal treatment of rutile TiO2 with LiOH to prepare an intermediate phase of LiTi2O4+δ, and the calcinations of LiTi2O4+δ to obtain spinel Li4Ti5O12. The as-prepared products are investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The diameters of Li4Ti5O12 submicrospheres with novel hierarchical microstructures are about 200–300 nm with the assembly of 20–30 nm nanoparticles. The electrochemical properties of Li4Ti5O12 submicrospheres are measured by galvanostatical discharge/charge test and cyclic voltammetry (CV). The as-prepared Li4Ti5O12 display excellent discharge/charge rate and cycling capability. A high discharge capacity of 174.3 mAh/g is obtained in the first discharge at 1 C rate. Meanwhile, there is only tiny capacity fading with nearly 100% columbic efficiency in the sequential 5–50 cycles. Moreover, lithium-ion diffusion coefficient in Li4Ti5O12 is calculated to be 1.03 × 10-7 cm2/s. The present results indicate that the as-prepared Li4Ti5O12 submicrospheres are promising anode candidates of rechargeable Li-ion batteries for high-power applications.ZHANG Ai, ZHENG ZongMin, CHENG FangYi, TAO ZhanLiang & CHEN Jun Key Laboratory of Advanced Energy Materials Chemistry, Ministry of Education College of Chemistry, Nankai University, Tianjin 300071, China 2011Science China Chemistry2011,54,6:9
12Consequence alimentary reconstruction in nutritional status after total gastrectomy for gastric cancer显示文摘NTODUCTIONToinvestigatethenutritionalconsequencesofgastroentericreconstructioninpatientswithgastriccanceraftertotalgastrecto...WU Yin Ai 1, LU Bin 1, LIU Jun 1, LI Jiang 1, CHEN Jiang Rong 2 and HU Shi Xiong 1 1999World Journal of Gastroenterology1999,5,1:8
13Association between Plasma Metal Levels and Diabetes Risk: a Case-control Study in China显示文摘Objective Many metals, some of which have been classified as environmental endocrine disruptors, are used extensively in everyday consumer products and are ubiquitous in our living environment. In the present study, we aimed to explore the associations between the prevalence risk of type 2 diabetes and plasma levels of 20 trace elements as well as those of heavy metals in a Han Chinese population. Methods We conducted a case-control study to investigate the associations between plasma concentrations of 20 metals and diabetes in Jiangsu province. A total of 122 newly diagnosed cases of type 2 diabetes and 429 matched controls were recruited from community physical examinations in Suzhou City of Jiangsu Province. Plasma metal levels were measured by inductively-coupled plasma mass spectrometry. Results After adjusting for confounders, plasma vanadium, chromium, manganese, copper, zinc, arsenic, selenium, strontium, palladium, cadmium, cesium, and barium were associated with diabetes risk(P < 0.05). The adjusted OR increased with increasing concentration of vanadium, manganese, copper, zinc, and cesium. Conclusion Many metals, including manganese, copper, zinc, arsenic, selenium, and cadmium in plasma, are associated with the morbidity of diabetes. Monitoring of environmental metal levels and further studies are urgently needed.LI Xiu Ting YU Peng Fei GAO Yan GUO Wen Hui WANG Jun LIU Xin GU Ai Hua JI Gui Xiang DONG Qiu WANG Bo Shen CAO Ying ZHU Bao Li XIAO Hang 2017Biomedical and Environmental Sciences2017,30,7:8
14Proton pump inhibitor for non-erosive reflux disease:A meta-analysis显示文摘AIM:To evaluate the efficacy,safety and influential factors of proton pump inhibitor(PPI)treatment for non-erosive reflux disease(NERD).METHODS:PubMed,MEDLINE,EMBASE and the Cochrane Library were searched up to April 2013 to identify eligible randomized controlled trials(RCTs)that probed into the efficacy,safety and influential factors of PPI treatment for NERD.The rates of symptomatic relief and adverse events were measured as the outcomes.After RCT selection,assessment and data collection,the pooled RRs and 95%CI were calculated.This meta-analysis was performed using the Stata 12.0 software(Stata Corporation,College Station,Texas,United States).The level of evidence was estimated by the Grading of Recommendations Assessment,Development and Evaluation system.RESULTS:Seventeen RCTs including 6072 patients met the inclusion criteria.The results of the metaanalysis showed that PPI treatment was significantly superior to H2receptor antagonists(H2RA)treatment(RR=1.629,95%CI:1.422-1.867,P=0.000)and placebo(RR=1.903,95%CI:1.573-2.302,P=0.000)for the symptomatic relief of NERD.However,there were no obvious differences between PPI and H2RA(RR=0.928,95%CI:0.776-1.110,P=0.414)or PPI and the placebo(RR=1.000,95%CI:0.896-1.116,P=0.997)regarding the rate of adverse events.The overall rate of symptomatic relief of PPI against NERD was 51.4%(95%CI:0.433-0.595,P=0.000),and relief was influenced by hiatal hernia(P=0.030).The adverse rate of PPI against NERD was 21.0%(95%CI:0.152-0.208,P=0.000),and was affected by hiatal hernia(P=0.081)and drinking(P=0.053).CONCLUSION:PPI overmatched H2RA on symptomatic relief rate but not on adverse rate for NERD.Its relief rate and adverse rate were influenced by hiatal hernia and drinking.Ji-Xiang Zhang Meng-Yao Ji Jia Song Hong-Bo Lei Shi Qiu Jing Wang Ming-Hua Ai Jun Wang Xiao-Guang Lv Zi-Rong Yang Wei-Guo Dong 2013World Journal of Gastroenterology2013,19,45:8
15H2 strain attenuated live hepatitis A vaccines:protective efficacy in a hepatitis A outbreak显示文摘AIM To investigate the protective efficacy ofH2 strain attenuated live hepatitis A vaccines(H2-strain vaccines)in hepatitis A(HA)outbreaks.METHODS With the permission of theirparents,5551 pre-school and grade 1-3 primaryschool children were inoculated with 1 dose(106.5TCID50)of H2-strain vaccines in anonrandomized,controlled trial conducted inFucheng County,Hebei Province in May 1997.Another 6485 children in the same grades andcompatible in gender and age were enrolled ascontrols.Epidemiological and serological surveywas conducted to evaluate the protectiveefficacy of the vaccines.ELISA was used todetect serum IgM anti-HAV.RESULTS HA outbreak started in early May1998,peaked in the middle of the same month,and lasted about 80 days.Overall 302 HA caseswere found,192(53.58%)were 5-9 years old.One vaccinee and 25 control cases were found tohave hepatitis A,which account for 0.28%(1/356)and 5.92%(25/422)of all vaccinees andcontrols in the 14 villages,respectively.The protective efficacy of vaccines was 95.27%(95% Cl:85.83%-104.72%).In subjects testedfor anti-HAV IgM from 13 villages,1(0.40%)overt and 11(4.06%)asymptomatic HAV caseswere found in 271 vaccinees,but 21(6.69%)ofovert and asymptomatic ones were found in 314controls.CONCLUSION H2 strain vaccines were excellent in preventing overt hepatitis A, but not so effective in preventing asymptomatic hepatitis A virus infection. A booster dose might be needed to get permanent reliable immunity.Yu Liang Zhao Zong Da Meng Zhi Yi Xu Jun Jie Guo Shao Ai Chai Cheng Gang Duo Xuan Yi Wang Jin Feng Yao Hong Bin Liu Shun Xiang Qi Hui Bin Zhu 2000World Journal of Gastroenterology2000,6,6:7
16Ghrelin improves delayed gastrointestinal transit in alloxan-induced diabetic mice显示文摘AIM: To investigate the effects of ghrelin on delayed gastrointestinal transit in alloxan-induced diabetic mice. METHODS: A diabetic mouse model was established by intraperitoneal injection with alloxan. Mice were randomized into two main groups: normal mice group and diabetic mice group treated with ghrelin at doses of 0, 20, 50, 100 and 200 μg/kg ip. Gastric emptying (GE), intestinal transit (IT), and colonic transit (CT) were studied in mice after they had a phenol red meal following injection of ghrelin. Based on the most effective ghrelin dosage, atropine was given at 1 mg/kg 15 min before the ghrelin injection for each measurement. The mice in each group were sacrificed 20 min later and their stomachs, intestines, and colons were harvested immediately. The amount of phenol red was measured. Percentages of GE, IT, and CT were calculated. RESULTS: Percentages of GE, IT, and CT were significantly decreased in diabetic mice as compared to control mice (22.9 ± 1.4 vs 28.1 ± 1.3, 33.5 ± 1.2 vs 43.2 ± 1.9, 29.5 ± 1.9 vs 36.3 ± 1.6, P < 0.05). In the diabetic mice, ghrelin improved both GE and IT, but not CT. The most effective dose of ghrelin was 100 μg/kg and atropine blocked the prokinetic effects of ghrelin on GE and IT.CONCLUSION: Ghrelin accelerates delayed GE and IT but has no effect on CT in diabetic mice. Ghrelin may exert its prokinetic effects via the cholinergic pathway in the enteric nervous system, and therefore has therapeutic potential for diabetic patients with delayed upper gastrointestinal transit.Wen-Cai Qiu Zhi-Gang Wang Ran Lv Wei-Gang Wang Xiao-Dong Han Jun Yan Yu Wang Qi Zheng Kai-Xing Ai 2008World Journal of Gastroenterology2008,14,16:7
17Composite solid electrolyte of Na3PS4-PEO for all-solid-state SnS2/Na batteries with excellent interfacial compatibility between electrolyte and Na metal显示文摘High ionic conductivity and superior interfacial stability of solid electrolytes at the electrodes are crucial factors for high-performance all-solid-state sodium batteries. Herein, a composite solid electrolyte Na3PS4-polyethylene oxide is synthesized by the solution-phase reaction method with an improved ionic conductivity up to 9.4 × 10-5 S/cm at room temperature. Moreover, polyethylene oxide polymer layer is wrapped homogeneously on the surface of Na3PS4 particles, which could effectively avoid the direct contact between Na3PS4 electrolyte and sodium metal, thus alleviate their side reactions. We demonstrate that all-solid-state battery SnS2/Na with the composite solid electrolyte Na3PS4-polyethylene oxide delivers an enhanced electrochemical performance with 230 m Ah/g after 40 cycles.Xiaoyan Xu Yuanyuan Li Jun Cheng Guangmei Hou Xiangkun Nie Qing Ai Linna Dai Jinkui Feng Lijie Ci 2020Journal of Energy Chemistry2020,29,2:7
18Prevalence of Anti-endothelial Cell Antibodies in Patients with Pulmonary Arterial Hypertension Associated with Connective Tissue Diseases显示文摘Objective To investigate the prevalence of anti-endothelial cell antibodies (AECAs) in the sera of connective tissue diseases (CTD) patients with pulmonary arterial hypertension (PAH) and its correlation with clinical manifestations. Methods AECAs in sera of 39 CTD patients with PAH,22 CTD patients without PAH,and 10 healthy donors as controls were detected with Western blotting. The prevalence of different AECAs in different groups was compared and its correlation with clinical manifestations was also investigated. Results The prevalence of AECAs was 82.1% in CTD patients with PAH,72.7% in CTD patients without PAH,and 20.0% in healthy donors. Anti-22 kD AECA was only detected in CTD patients with PAH (15.4%). Anti-75 kD AECA was more frequently detected in CTD patients with PAH than in those without PAH (51.3% vs. 22.7%,P<0.05). In CTD patients with PAH,anti-75 kD AECA was more frequently detected in those with Raynaud’s phenomenon or with positive anti-RNP antibody. Conclusion AECAs could be frequently detected in CTD patients with or without PAH,while anti-22 kD and anti-75 kD AECA might be specific in CTD patients with PAH.Meng-tao Li Jun Ai Zhuang Tian Quan Fang Wen-jie Zheng Xue-jun Zeng Xiao-feng Zeng 2010Chinese Medical Sciences Journal2010,25,1:7
19Optimization on conventional and electric air-cycle refrigeration systems of aircraft: A short-cut method and analysis显示文摘The air-cycle refrigeration system is widely used in commercial and military aircraft,and its efficiency greatly affects aircraft performance.Nowadays,this system requires a more efficient design and optimization method.In this paper,a short-cut optimization method with high efficiency and effectiveness is introduced for both conventional and electric air-cycle refrigeration systems.Based on the system characteristics,a four-layer parameter matching algorithm is designed which avoids computational difficulty caused by simultaneous equations.Fuel penalty is chosen as the objective function of optimization;design variables are reduced based on sensitivity analysis to improve optimization efficiency.The results show that the 3-variable optimization of the conventional air-cycle refrigeration system can obtain almost the same results as the traditional 6-variable optimization in that these two optimizations can both significantly reduce the fuel penalty.However,the computer running time of the 3-variable optimization is much shorter than that of the 6-variable optimization.The optimal fuel penalty of the electric air-cycle refrigeration system is lower than that of the conventional one.This study can provide reference for optimizing the aircycle refrigeration system of aircraft.Hongsheng JIANG Sujun DONG Hainan ZHANG Fengming AI Zhiwei ZHANG Jun WANG 2020Chinese Journal of Aeronautics2020,33,7:6
20Relationship Between Thermal Shock Behavior and Cutting Performance of a Functionally Gradient Ceramic Tool显示文摘Based on the deep understanding of the requirements of cutting conditions on ceramic tools, a design model for functionally gradient ceramic tool materials with symmetrical composition distribution was presented in this paper, according to which an Al 2O 3-TiC functionally gradient ceramic tool material FG-1 was synthesized by powder-laminating and uniaxially hot-pressing technique. The thermal shock resistance of the Al 2O 3-TiC functionally gradient ceramics FG-1 was evaluated by water quenching and subsequent three-point bending tests of flexural strength diminution. Comparisons were made with results from parallel experiments conducted using a homogeneous Al 2O 3-TiC ceramics. Functionally gradient ceramics exhibited higher retained strength under all thermal shock temperature differences compared to homogeneous ceramics, indicating the higher thermal shock resistance. The experimental results were supported by the calculation of transient thermal stress field. The cutting performance of the Al 2O 3-TiC functionally gradient ceramic tool FG-1 was also investigated in rough turning the cylindrical surface of exhaust valve of diesel engine in comparison with that of a common Al 2O 3-TiC ceramic tool LT55. The results indicated that the tool life of FG-1 increased by 50 percent over that of LT55. Tool life of LT55 was mainly controlled by thermal shock cracking which was accompanied by mechanical shock. While tool life of FG-1 was mainly controlled by mechanical fatigue crack extension rather than thermal shock cracking, revealing the less thermal shock susceptibility of functionally gradient ceramics than that of common ceramics.ZHAO Jun, AI Xing, HUANG Xin-ping (School of Mechanical Engineering, Shandong University, Jinan 250061, China) 2002厦门大学学报(自然科学版)2002,41,S1:6
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