维普中文期刊产品整合服务
66031篇 您的检索式:作者名="S chen"
    题名 作者 年代 出处 被引量
1激光剥蚀信号在线平滑和去汞装置:原位微区铅同位素准确分析利器显示文摘激光原位微区分析可在微观尺度上完成样品的元素定量分析或同位素组成测定,为研究成岩、成矿物质来源和追踪地壳与地幔演化历史提供了独特的观察视野。但是,激光剥蚀等离子体质谱的一些缺陷阻碍了地质样品的高精度、高空间分辨率分析,比如:剥蚀池的位置效应、低剥蚀速率下信号波动影响、激光剥蚀脉动式信号导致的光谱螺纹效应、高频激光剥蚀造成的元素分馏效应等。为此,一些学者设计了不同规格和样式的激光剥蚀信号平滑装置来克服这些问题。但是,这些信号平滑装置普遍还存在气体吹扫时间过长和降低激光剥蚀信号灵敏度等问题。因此,研制新型的信号平滑装置对改善LA—ICP—MS的数据质量具有重要的意义。Hu Z Zhang W Liu Y Gao S Li M Zong K Chen H Hu S 刘勇胜 2015矿物岩石地球化学通报2015,34,4:114
2Helicobacter pylori associated chronic gastritis,clinical syndromes,precancerous lesions,and pathogenesis of gastric cancer development显示文摘Helicobacter pylori(H.pylori)infection is well known to be associated with the development of precancerous lesions such as chronic atrophic gastritis(AG),or gastric intestinal metaplasia(GIM),and cancer.Various molecular alterations are identified not only in gastric cancer(GC)but also in precancerous lesions.H.pylori treatment seems to improve AG and GIM,but still remains controversial.In contrast,many studies,including meta-analysis,show that H.pylori eradication reduces GC.Molecular markers detected by genetic and epigenetic alterations related to carcinogenesis reverse following H.pylori eradication.This indicates that these changes may be an important factor in the identification of high risk patients for cancer development.Patients who underwent endoscopic treatment of GC are at high risk for development of metachronous GC.A randomized controlled trial from Japan concluded that prophylactic eradication of H.pylori after endoscopic resection should be used to prevent the development of metachronous GC,but recent retrospective studies did not show the tendency.Patients with precancerous lesions(molecular alterations)that do not reverse after H.pylori treatment,represent the'point of no return'and may be at high risk for the development of GC.Therefore,earlier H.pylori eradication should be considered for preventing GC development prior to the appearance of precancerous lesions.Jiro Watari Nancy Chen Peter S Amenta Hirokazu Fukui Tadayuki Oshima Toshihiko Tomita Hiroto Miwa Kheng-Jim Lim Kiron M Das 2014World Journal of Gastroenterology2014,20,18:60
3Characteristics of Obesity and Its Related Disorders in China显示文摘Obesity is a medical condition with excess body fat accumulation to the extent which leads to serious health consequences.Abdominal obesity,also known as central obesity,refers to the presence of excess fat in the abdominal area.Obesity,especially abdominal obesity,contributes to many metabolic disorders including metabolic syndrome (MetS),type 2 diabetes (T2DM) and cardiovascular diseases (CVD).The incidence of obesity has increased dramatically in recent years worldwide.In China,more than one-third of adults are overweight or obese and 10%-20% of all adults are affected by MetS.The pathogenesis underlying the abdominal obesity remains unclear.The ultimate health outcome of obesity and its related metabolic disorders have prompted physicians to take aggressive treatments (lifestyle changes,pharmacological interventions and surgical therapies) before a serious consequence becomes clinically apparent.In this review,we discuss the prevalence,pathogenesis and clinic features of obesity in China.WEI-PING JIA ,CHEN WANG,SHAN JIANG,AND JIE-MIN PAN Department of Endocrinology and Metabolism,Shanghai Jiao Tong University Affiliated Sixth People’s Hospital,Shanghai Diabetes Institute,Shanghai Clinical Center of Diabetes,Shanghai 200233,China 2010Biomedical and Environmental Sciences2010,23,1:46
4Expression,deleton and mnutation of ρ16 gene in human gastric cancer显示文摘AIM To investigate the relationship between the expression of p16 gene and the gastric carcinogenesis,depth of invasion and lymph node metastases, and to evaluate the deletion and mutation of exon 2 in p16 gene in gastric carcinoma.METHODS The expression of P16 protein was examined by streptavidin-peroxidase conjugated method (S-P); the deletion and mutation of p16 gene were respectively examined by polymerase chain reaction (PCR) and polymerase chain reaction single-strand conformation polymorphism analysis (PCR-SSCP) in gastric carcinoma.RESULTS Expression of P16 protein was detected in 96.25% (77/80) of the normal gastric mucosa, in 92.00% (45/50) of the dysplastic gastric mucosa and in 47.54% (58/122) of the gastric carcinoma. The positive rate of P16 protein expression in gastric carcinoma was significantly lower than that in normal gastric mucosa and dysplastic gastric mucosa (P<0.05). The positive rate of P16 protein expression in mucoid carcinoma 10.00% (1/ 10) was significantly lower than that in poorly differentiated carcinoma 51.22% ( 21/ 41 ),undifferentiated carcinoma 57.69% (15/26) and signet ring cell carcinoma 62.50% (10/ 16) (P<0.05). The positive rate of p16 protein in 30 cases paired primary and lymph node metastatic gastric carcinoma: There was 46.67% (14/30) in primary gastric carcinoma, 16.67% (5/30) in lymph node metastatic gastric carcinoma. The positive rate of lymph node metastatic carcinoma was significantly lower than that of primary carcinoma (P<0.05). There was of p16 gene mutation in exon 2, but 5 cases displayed deletion of p16 gene in exon 2 in the 25 primary gastric carcinomas.CONCLUSIONS The expression loss of P16 protein related to the gastric carcinogenesis, gastric carcinoma histopathological subtypes and lymph metastasis. The mutation of p16 gene in exon 2 may not be involved in gastric carcinogenesis. But the deletion of p16 gene in exon 2 may be involved in gastric carcinogenesis.Xiu-Sheng He Qi Su Zhu-Chu Chen Xiu-Tao He Zhi-Feng Long Hui Ling Liang-Run Zhang Oncology Institute,Nanhua University,Hengyang 421001,Hunan Province,ChinaOncology Institute,Center South University,Changsha 410078,Hunan Province,China Department of Gastroenterology,First People’s Hospital of Changde City,Changde 415003,Hunan Province,China 2001World Journal of Gastroenterology2001,7,4:40
5Expression of the B7 - related molecule B7 - H1 by glioma cells: a potential mechanism of immune paralysis显示文摘Human glioblastoma is a highly lethal tumor that is known for its immune inhibitory capabilities.B7-homologue l(B7-H 1),a recently identified homologue of B7.1/2(CD80/86),has been described to exert costimulatoryand immune regulatory functions.We investigated the expression and the functional activity of B7-H 1 in humanglioma cells in vitro and in vivo.Although lacking B7.1/2(CD80/86),all 12 glioma cel1 1ines constitutivelyexpressed B7-H1 mRNA and protein.Exposure to IFN-gamma strongly enhanced B7-H 1 expression.Im-Wintterle S Schreiner B Mitsdoerffer M Schneider D Chen Meyermann R Weller M Wiendl H 2003中国神经肿瘤杂志2003,1,4:37
6Draining Tangjiashan Barrier Lake after Wenchuan Earthquake and the flood propagation after the dam break显示文摘Tangjiashan Barrier Lake is one of the largest barrier lakes caused by the Wenchuan Earthquake. Its risk analysis, emergency plan and effect of the emergency plan are introduced in this paper. The dam height of Tangjiashan Barrier Dam is about 105 m, and the reservoir storage capacity is 3.2×108 m3. When the dam broke the flood peak were estimated to be larger than 48000 m3/s, which might cause a enormous disaster to the downstream cities and residents. A discharge channel with 13 m deep and 8 m wide was drug, so that the water may flow out of the lake before the dam breaks. As a result, the drainage and risk mitigation project are successful. During the drainage process, the flood peak was about 6500 m3/s, and about 1.6×108 m3 of water was drained off and the residual reservoir capacity was only 8.97×107 m3. A new channel with average width 100 m was formed, which can bear floods of 200 years frequency. The successful experience and the collected data can be used to deal with the similar natural disasters in future.LIU Ning1, ZHANG JianXin2, LIN Wei3, CHENG WuYI4 & CHEN ZuYu5 1 Ministry of Water Resources of the People’s Republic of China, Beijing 100053, China 2 Bureau of Hydrology of the Ministry of Water Resources of the People’s Republic of China, Beijing 100053, China 3 Sichuan Hydrographic and Water Resources Survey Bureau Chengdu 610031, China 4 HydroChina Chengdu Engineering Corporation, Chengdu 610072, China 5 China Institute of Water Resources and Hydropower Research, Beijing 100044, China 2009Science China(Technological Sciences)2009,52,4:29
7Structure and function of aggrecan显示文摘Aggrecan is the major proteoglycan in the articular cartilage. This molecule is important in the proper functioning of articular cartilage because it provides a hydrated gel structure (via its interaction with hyaluronan and link protein) that endows the cartilage with load-bearing properties. It is also crucial in chondroskeletal morphogenesis during development. Aggrecan is a multimodular molecule expressed by chondrocytes. Its core protein is composed of three globular domains (G1, G2, and G3) and a large extended region (CS) between G2 and G3 for glycosaminoglycan chain attachment. G1 comprises the amino terminus of the core protein. This domain has the same structural motif as link protein. Functionally, the G1 domain interacts with hyaluronan acid and link protein, forming stable ternary complexes in the extracellular matrix. G2 is homologous to the tandem repeats of G1 and of link protein and is involved in product processing. G3 makes up the carboxyl terminus of the core protein. It enhances glycosaminoglycan modification and product secretion. Aggrecan plays an important role in mediating chondrocyte-chondrocyte and chondrocyte-matrix interactions through its ability to bind hyaluronan.CHRIS KIANI, LIWEN CHEN, YAO JIONG WU, ALBERT J YEE, BURTON B YANG, Sunnybrook and Women’s College Health Sciences Centre and Department of Laboratory Medicine and Patobiology, 2 Department of Surgeny, Faculty of Medicine, University of Toronto, Canada 2002Cell Research2002,12,1:27
8Metabolic profiling analysis of a D-galactosamine/lipopolysaccharide- induced mouse model of fulminant hepatic failure显示文摘Feng, B Wu, SM Lv, S Liu, F Chen, HS Yan, XZ Li, Y Dong, FT Wei, L 2007中国生物学文摘2007,21,11:23
9Changed clinical aspects of primary liver cancer in China during the past 30 years显示文摘BACKGROUND: Primary liver cancer (PLC) is one of the most frequently seen tumors in China. Thirty years ago, patients with PLC were often detected at relatively late stage, with a palpable mass or marked clinical symptoms and poor prognosis. In the past 30 years, the diagnosis and treatment of PLC have been greatly improved with better prognosis. METHODS: In order to study the changes of PLC during the 30 years, the clinical data of 3250 patients with PLC from 10 medical institutions of China were collected, ana- lyzed , and compared with those of 3254 PLC patients be- fore the 30 years. RESULTS: In the 3250 patients aged 1-80 years, with an average age of 49.1 years, the male to female ratio (2.3:1) was lower than that before the 30 years. 73.5% of the 3250 patients sought medical advice within 3 months after the onset of the disease in contrast to 63.8% before the 30 years. Compared with those patients before the 30 years the symptoms and signs were alleviated generally. The HBsAg positive rate was 81.0%, but the HCV-Ab positive rate was 13.2%. The AFP level in 75% of patients was elevated, but in the remaining 25% was normal. 1912 patients (58.8%) were confirmed pathologically. Among them 1755 patients (91.8%) had hepatocellular carcinoma. The overall resec- tion rate was 46.3%. Those who had early, middle, late stage carcinoma accounted for 29.9%, 51.5%, and 18.6%respectively in contrast to 0.4%, 47.0%, and 52.6% repor- ted before the 30 years. The 1-, 3-, 5-year survival rates of the patients were 66.1%, 39.7%, and 32.5% respectively, whereas 93.5%, 70.1%, and 59.1% for the early stage pa- tients, and 65.3%, 30.5%, and 23.5% for the middle stage patients. The half and 1-year survival rates of the late stage patients were 52.5%, and 14.7%, respectively. CONCLUSION: Comparison with the clinical data before and after the 30 years show that PLC can be diagnosed ear- ly. More PLC patients tend to undergo resection while re- ceiving a better conservative treatment, which ensures a prognosis.Bing-Hui Yang, Jing-Lin Xia, Li-Wen Huang, Zhao-You Tang, Ming-Shan Chen, Jin-Qing Li, An-Min Liang, Qin-Guo Mo, Hui-Shan Lu, Chao-Liu Dai, Lu-Nan Yan, Zhi-Jian Yu, Rong-Sheng Rao, Le-Qun Li, Zhi-Xiong Su, Zhuang-Wei Fang Shanghai, China Liver Cancer Institute & Zhongshan Hospital, Fudan University, Shanghai 200032, China Tumor Hospital, Zhongshan University, Guangzhou 510000, China Tumor Hospital, Guangxi Medical Universi- ty, Nanning 530000, China Xiehe Hospital, Fujian Medical University, Fuzhou 350000, China Second Hos- pital, Chinese Medical University, Shenyang 110000, China Huaxi Hospital, Sichuan University, Chengdu 610041, China Hospital Affiliated to Nantong Medical University, Nantong 226000 , China Second Hospital, Jiangxi Medical University, Nanchang 330000 , China First Hospital Affiliated to Guangxi Medical University, Nanning 530000 , China People’s Hospital of Hainan Province, Haikou 570000, China 2004Hepatobiliary & Pancreatic Diseases International2004,3,2:20
10microRNA-181b targets MLK2 in HL-60 cells显示文摘microRNAs(miRNAs) play critical roles in many different cellular processes,including metabolism,apoptosis,differentiation and development.We showed miR-181b to be highly expressed in acute myeloid leukemia(AML).Furthermore,miR-181b contributed to proliferation of AML cells by targeting MLK2.Our results demonstrated that miR-181b plays an important role in the biology of AML and may be useful in developing therapies targeting miRNAs.CHEN Hong1,CHEN Qun2,FANG Ming3 & MI Yan1 1 The First Affiliated Hospital of Harbin Medical University,Harbin 150101,China 2 Harbin Acheng District People’s Hospital,Harbin 150300,China 3 Graduate Department of Harbin Medical University,Harbin 150001,China 2010Science China(Life Sciences)2010,53,1:20
11Ten-year survival of hepatocellular carcinoma patients undergoing radiofrequency ablation as a first-line treatment显示文摘AIM: To investigate the long-term survival and prognostic factors in hepatocellular carcinoma(HCC) patients undergoing radiofrequency ablation(RFA) as a first-line treatment.METHODS: From 2000 to 2013, 316 consecutivepatients with 404 HCC(1.0-5.0 cm; mean: 3.2 ± 1.1 cm) underwent ultrasonography-guided percutaneous RFA as a first-line treatment. There were 250 males and 66 females with an average age of 60.1 ± 10.8 years(24-87 years). Patients were followed for 1 year to > 10 years after RFA(234, 181, 136, and 71 for 3, 5, 7, and 10 years, respectively). Overall local response rates and long-term survival rates were assessed. Survival results were generated using Kaplan-Meier estimates, and multivariate analysis was performed using the Cox regression model. RESULTS: In total, 548 RFA sessions were performed and major complications occurred in 10 sessions(1.8%). Local tumor progression and/or new tumor development were observed in 43.3%(132/305) of the patients during the follow-up period. Overall 5-and 10-year survival rates were 49.7% and 28.4%, respectively. Based on multivariate analysis, three factors were identified as independent prognostic factors for overall survival: Child-Pugh classification(HR = 4.054, P < 0.001), portal vein hypertension(HR = 2.743, P = 0.002), and tumor number(HR = 2.693, P = 0.003). The local progression-free 5- and 10-year survival rates were 42.7% and 19.5%. In addition to the Child-Pugh classification and the number of tumors, the number of RFA sessions(HR = 1.550, P = 0.002) was associated with local progression-free survival.CONCLUSION: RFA can achieve acceptable outcomes for HCC patients as a first-line treatment, especially for patients with Child-Pugh class A, patients with a single tumor and patients without portal vein hypertension.Wei Yang Kun Yan S Nahum Goldberg Muneeb Ahmed Jung-Chieh Lee Wei Wu Zhong-Yi Zhang Song Wang Min-Hua Chen 2016World Journal of Gastroenterology2016,22,10:20
12Effect of N-desulfated heparin on hepatic/renal ischemia reperfusion injury in rats显示文摘AIM: To investigate the effect of N-desulfated heparin onhepatic/renal ischemia and reperfusion injury in rats.METHODS: Using rat models of 60 minutes hepatic or renalischemia followed by 1 h,3 h,6 h and 24 h reperfusion,animalswere randomly divided into following groups,the shamoperated controls,ischemic group receiving only normalsaline,and treated group receiving N-desulfated heparin ata dose of 12 mg/kg at 5 minutes before reperfusion. P-selectin expression was detected in bepatic/renal tissueswith immunohistochemistry methodRESULTS: P-selectin expression, serum ALT, AST, BUN andCr levels were significantly increased during 60 minuteischemia and 1 h, 3 h, 6 h and 24 h reperfusion,while theincrement was significantly inhibited,and hepatic/renalpathology observed by light microscopy was remarkablyimproved by treatment with the N-desulfated heparin.Furthermore,the heparin was found no effects on PT and KPTT.CONCLUSION: P-selectin might mediate neutrophilinfiltration and contribute to hepatic/renal ischemia andreperfusion. The N-desulfated heparin might preventhepatic/renal damage induced by ischemia and reperfusioninjury without significant anticoagulant activity.Tong Zhou Wei Song Feng Wang Department of Nephrology,Ruijin Hospital,Shanghai Second Medical University,Shanghai 200025,China Jin-Lian Chen Department of Gastroenterology,Shanghai Sixth People’s Hospital,Shanghai 200233,China Ming-Jun Zhang Animal Laboratory,Ruijin Hospital,Shanghai Second Medical University,Shanghai 200025,China Pei-Hua Ni,Department of Biochemistry,Shanghai Second Medical University,Shanghai 200025 Jian-Guo Geng Institute of Biochemistry and Cell Biology,Shanghai 200030,China 2002World Journal of Gastroenterology2002,8,5:20
13血管性认知障碍的诊断标准:国际血管性行为与认知障碍学会的申明显示文摘长期以来,脑血管病(CVD)就被认为是认知损害的一个重要原因,但是有关脑血管病后认知障碍的概念化却有着一段多变的历史。'动脉变硬'或脑的动脉粥样硬化是'老化'的原因,是存在已久的观点,在20世纪60年代受到了来自英格兰纽卡斯尔的神经病理学研究的质疑。这些研究表明,血管性痴呆(vascular dementia,Va D)与超过一定程度的多发性脑梗死有关。徐岩 郭起浩 Sachdev P Kalaria R O'Brien J Skoog I Alladi S Black SE Blacker D Blazer DG Chen C Chui H Ganguli M Jellinger K Jeste DV Pasquier F Paulsen J Prins N Rockwood K Roman G Scheltens P 2014神经病学与神经康复学杂志2014,11,3:19
14Meta-analyses on prevalence of selected Parkinson’s nonmotor symptoms before and after diagnosis显示文摘Background:Nonmotor symptoms are common among patients with Parkinson’s disease(PD)and some may precede disease diagnosis.Methods:We conducted a meta-analysis on the prevalence of selected nonmotor symptoms before and after PD diagnosis,using random-effect models.We searched PubMed(1965 through October/November 2012)for the following symptoms:hyposmia,constipation,rapid eye movement sleep behavior disorder,excessive daytime sleepiness,depression,and anxiety.Eligible studies were publications in English with original data on one or more of these symptoms.Results:The search generated 2,373 non-duplicated publications and 332 met the inclusion criteria,mostly(n=320)on symptoms after PD diagnosis.For all symptoms,the prevalence was substantially higher in PD cases than in controls,each affecting over a third of the patients.Hyposmia was the most prevalent(75.5%in cases vs.19.1%in controls),followed by constipation(50%vs.17.7%),anxiety(39.9%vs.19.1%),rapid eye movement sleep behavior disorder(37.0%vs.7.0%),depression(36.6%vs.14.9%),and excessive daytime sleepiness(33.9%vs.10.5%).We observed substantial heterogeneities across studies and meta-regression analyses suggested that several factors might have contributed to this.However,the prevalence estimates were fairly robust in several sensitivity analyses.Only 20 studies had data on any symptoms prior to PD diagnosis,but still the analyses revealed higher prevalence in future PD cases than in controls.Conclusion:These symptoms are common among PD patients both before and after diagnosis.Further studies are needed to understand the natural history of nonmotor symptoms in PD and their etiological and clinical implications.Honglei Chen Edward J Zhao Wen Zhang Yi Lu Rui Liu Xuemei Huang Anna J Ciesielski-Jones Michele A Justice Deborah S Cousins Shyamal Peddada 2015Translational Neurodegeneration2015,4,1:18
155-Hydroxymethylcytosine signatures in cell-free DNA provide information about tumor types and stages显示文摘5-Hydroxymethylcytosine (5hmC ) 是被连接了到基因规定和癌症致病的重要哺乳动物的 DNA epigenetic 修正。这里,我们用定序途径的一枝敏感化学基于标签的低输入的猎枪在传播没有房间的 DNA (cfDNA ) 探索了 5hmC 的诊断潜力。我们从七种不同癌症类型的 49 个病人定序没有房间的 5hmC 并且发现了能被用来与高精确性预言癌症类型和阶段的不同特征。明确地,我们发现肺癌症在 cfDNA 导致 5hmC 的进步全球损失,而 hepatocellular 癌和胰腺的癌症在没有房间的 hydroxymethylome 导致疾病特定的变化。我们的 proof-of-principle 结果建议没有房间的 5hmC 签名可以潜在地被使用不仅识别癌症类型而且在一些癌症追踪肿瘤舞台。Chun-Xiao Song Senlin Yin Li Ma Amanda Wheeler Yu Chen Yan Zhang Bin Liu Junjie Xiong Weihan Zhang Jiankun Hu Zongguang Zhou Biao Dong Zhiqi Tian Stefanie S Jeffrey Mei-Sze Chua Samuel So Weimin Li Yuquan Wei Jiajie Diao Dan Xie Stephen R Quake 2017Cell Research2017,27,10:17
16Multilineage differentiation of adipose-derived stromal cells from GFP transgenic mice显示文摘Lin Y Chen X Yan Z Liu L Tang W Zheng X Li Z Qiao J Li S Tian W 2006中国生物学文摘2006,20,5:16
17Asymptomatic process of hepatic artery thrombosis in a patient after orthotopic liver transplantation显示文摘BACKGROUND: Hepatic artery thrombosis is one of the serious complications after liver transplantation. It wil mostly cause a failure of the transplantation. This case o hepatic artery thrombosis showed a stable clinical course and minimal histological change, and now has been survi ving for 4 years with normal liver function. We investigated the possible causes for asymptomatic hepatic artery throm bosis in one patient after orthotopic liver transplantation ( OLT) and discussed the diagnosis of ischemia of OLT pathologically and clinically. METHODS: Liver function test, color Doppler ultrasono graphy, and hepatic arteriography were performed during the development of hepatic arteriothrombosis. Possible fac- tors for the asymptomatic process of the thrombosis were analyzed. RESULTS: On the 4th postoperative day, thrombosis form ed at the anastomotic stoma of the hepatic artery, and on the 11th postoperative day, the artery was completely oc- cluded. Serial liver biopsies revealed intrahepatic cholesta- sis, hydropic degeneration of hepatocytes, atrophy of the biliary epithelium, and fibrosis in the portal area. Monitor- ing of liver function showed nothing abnormal except ele- vation of γ-GT and ALP levels. On the 71st day after OLT, arteriography demonstrated that the hepatic artery re- mained completely occluded in addition to the establish- ment of collateral circulation and compensation of the por- tal vein. The patient didn’ t show any symptoms of arterial thrombosis. CONCLUSION: Collateral circulation and compensation o the portal vein are beneficial to allograft survival and avoidence of retransplantation after thrombosis of the he- patic artery. Color Doppler ultrasonography within 2 weeks after OLT is helpful to the early diagnosis of hepatic arterio- thrombosis.Jia-Wei Chen, Da-Zhi Chen and Guang-Zhong Lu Shanghai, China Department of Pathology, Shanghai First People’ s Hospital, Shanghai 200080 , China Department of Surgery, Beijing Chaoyang Hospital, Beijing 100020, China 2004Hepatobiliary & Pancreatic Diseases International2004,3,1:15
18THE IMPROVEMENT OF ELECTRON FIELD EMISSION FROM AMORPHOUS CARBON FILMS DUE TO HYDROGEN PLASMA CHEMICAL ANNEALING EFFECT显示文摘Hydrogenated amorphous carbon films were fabricated by using layer-by-layer deposition method and hydrogen dilution method in a small d.c.-assisted plasma enhanced chemical vapor deposition system. It was found that the hydrogen plasma treatment could change the sp2/sp3 ratio to some extent by chemical etching. The improvements of field emission characteristics were observed compared with that from conventionally deposited a-C films, which can be attributed to the large field enhancement effect due to the inhomogeneous distribution of nanometer scale sp2 clusters and the reduction of the surface emission barrier due to the hydrogen termination.J. Xu, X.H. Huang, L. Wang, W. Li and K.J. Chen (National Laboratory of Solid State Microstructures and Departmeat of Physics, Nanjing University, Nanjing 210093, China) J.B. Xu (Department of Electronic Engineering, The Chinese University of Hong Kong, S 2001Acta Metallurgica Sinica(English Letters)2001,14,6:15
19中国社区健康素养与高血压治疗之间的关系:回顾性队列研究显示文摘健康素养较低与临床预后差相关。健康素养与血压之间的关系研究结果不一致。该研究调查了健康素养的决定因素和健康素养与高血压管理之间的潜在关系。方法:对360例高血压患者进行回顾性队列研究。基于标准方案进行测量、体检和实验室检查。刘莉 叶鹏 Shi D Li J Wang Y Wang S Liu K Shi R Zhang Q Chen X 2017中华高血压杂志2017,25,5:14
20The Qitai radio telescope显示文摘This study presents a general outline of the Qitai radio telescope(QTT)project.Qitai,the site of the telescope,is a county of Xinjiang Uygur Autonomous Region of China,located in the east Tianshan Mountains at an elevation of about 1800 m.The QTT is a fully steerable,Gregorian-type telescope with a standard parabolic main reflector of 110 m diameter.The QTT has adopted an umbrella support,homology-symmetric lightweight design.The main reflector is active so that the deformation caused by gravity can be corrected.The structural design aims to ultimately allow high-sensitivity observations from 150 MHz up to115 GHz.To satisfy the requirements for early scientific goals,the QTTwill be equipped with ultra-wideband receivers and large field-of-view multi-beam receivers.A multi-function signal-processing system based on RFSo C and GPU processor chips will be developed.These will enable the QTT to operate in pulsar,spectral line,continuum and Very Long Baseline Interferometer(VLBI)observing modes.Electromagnetic compatibility(EMC)and radio frequency interference(RFI)control techniques are adopted throughout the system design.The QTT will form a world-class observational platform for the detection of lowfrequency(nano Hertz)gravitational waves through pulsar timing array(PTA)techniques,pulsar surveys,the discovery of binary black-hole systems,and exploring dark matter and the origin of life in the universe.The QTT will also play an important role in improving the Chinese and international VLBI networks,allowing high-sensitivity and high-resolution observations of the nuclei of distant galaxies and gravitational lensing systems.Deep astrometric observations will also contribute to improving the accuracy of the celestial reference frame.Potentially,the QTT will be able to support future space activities such as planetary exploration in the solar system and to contribute to the search for extraterrestrial intelligence.Na Wang Qian Xu Jun Ma Zhiyong Liu Qi Liu Hailong Zhang Xin Pei Maozheng Chen Richard N.Manchester Kejia Lee Xingwu Zheng Hans J.Kärcher Wulin Zhao Hongwei Li Dongwei Li Martin Süss Matthias Reichert Zhongyi Zhu Congsi Wang Mingshuai Li Rui Li Ning Li Guljaina Kazezkhan Wenming Yan Gang Wu Lang Cui Ming Zhang Haitao Li 2023Science China(Physics,Mechanics & Astronomy)2023,66,8:14
返回顶部 每页显示:
共3302页 首页 上一页 第1页 下一页 末页 /3302 跳转

网站首页 | 关于我们 | 联系我们 | 产品服务 | 客服中心 | 广告服务 | 版权声明 | 网站联盟 | 友情链接 | 售卡网点

版权所有© 渝B2-20050021-1 渝公网安备 50019002500403号 违法和不良信息举报中心

互联网出版许可证 新出网证(渝)字10号 全国400电话 - 免长途话费