期刊文献+
共找到15篇文章
< 1 >
每页显示 20 50 100
SCM435曲轴钢坯低倍缺陷分析
1
作者 张学礼 崔泽生 +1 位作者 惠勇健 胡士英 《理化检验(物理分册)》 CAS 1990年第3期48-51,共4页
关键词 SCM435钢 缺稳 曲轴钢
下载PDF
Microsatellite Alterations on Chromosome 8 of Hepatocellular Carcinoma 被引量:1
2
作者 张树辉 冼志红 +1 位作者 丛文铭 吴孟超 《The Chinese-German Journal of Clinical Oncology》 CAS 2004年第1期5-10,64,共7页
Objective: To study the features of microsatellite alterations on chromosome 8 and their asso- ciation with clinicopathological characteristics of hepatocellular carcinoma (HCC). Methods: Ten highly- ... Objective: To study the features of microsatellite alterations on chromosome 8 and their asso- ciation with clinicopathological characteristics of hepatocellular carcinoma (HCC). Methods: Ten highly- polymorphic microsatellite markers on chromosome 8 were selected to be detected for loss of heterozygosity (LOH), microsatellite instability (MSI) and allelic imbalance (AI) in 56 HCC using MegaBACE 500 auto- matic DNA analysis system. Results: LOH was found in 37 of 56 HCC (66.1%) on at least 1 locus, and the top three loci were D8S261(53.5%), D8S1721(52.5%) and D8S1771(52.5%). LOH frequency on D8S277 was signi?cantly higher in cases positive for serum HBsAg than in those negative for HBsAg (P <0.01). Similarly, LOH on D8S261, D8S298 and D8S1733 occurred more frequently in patients with negative HB- sAg than those with positive HBsAg (P <0.01). LOH on D8S298 and D8S1771 was more frequent in those tumors larger than 3 cm in size (P <0.05 or P <0.01). LOH frequencies of D8S1721 were signi?cantly higher in the patients with absent or not intact tumor capsule than in those with intact tumor capsule (P <0.05). LOH on D8S298 and D8S1771 was more frequently detected in tumors with intrahepatic metastasis than in those without intrahepatic metastasis (P <0.01). MSI was found in 12.5% (7/56) cases, and AI was found in 19.6% (11/56), no correlation was found between MSI and AI and clinicopathological character- istics of HCC. Conclusion: Frequent microsatellite alterations on chromosome 8 existed in HCC. LOH, which represents tumor suppressor gene pathway, plays a more important role in hepatocarcinogenesis; MSI representing mismatch repair gene pathway ranks next. LOH at a particula locus is associated with the clinicopathological parameters of human HCC. 展开更多
关键词 liver neoplasms carcinoma hepatocellular loss of heterozygosity microsatellite instability allelic imbalance
下载PDF
The origin of the extraordinary stability of mercury catalysts on the carbon support: the synergy effects between oxygen groups and defects revealed from a combined experimental and DFT study 被引量:5
3
作者 Jian Li Jiangtao Fan +6 位作者 Sajjad Ali Guojun Lan Haodong Tang Wenfeng Han Huazhang Liu Bo Li Ying Li 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第2期141-146,共6页
Thermal stability of HgCl2 has a pivotal importance for the hydrochlorination reaction as the loss of mercuric compounds is toxic and detrimental to environment.Here we report a low-mercury catalyst which has durabili... Thermal stability of HgCl2 has a pivotal importance for the hydrochlorination reaction as the loss of mercuric compounds is toxic and detrimental to environment.Here we report a low-mercury catalyst which has durability over 10000 h for acetylene hydrochlorination under the industrial condition.The stability of the catalyst is carefully analyzed from a combined experimental and density functional theory study.The analysis shows that the extraordinary stability of mercury catalyst is resulted from the synergy effects between surface oxygen groups and defective edge sites.The binding energy of HgCl2 is increased to be higher than 130 kJ/mol when adsorption is at the edge site with a nearby oxygen group.Therefore,the present study revealed that the thermal stability problem of mercury-based catalyst can be solved by simply adjusting the surface chemistry of activated carbon.Furthermore,the reported catalyst has already been successfully applied in the commercialized production of vinyl chloride. 展开更多
关键词 Mercury catalysts Thermal stability DEFECTS Oxygen groups Acetylene hydrochlorination
下载PDF
Stability of columns with original defects under periodic transient loadings 被引量:1
4
作者 Cai Yong Xie Jiawei 《Journal of Southeast University(English Edition)》 EI CAS 2017年第1期64-69,共6页
To study the influence of original defects on the dynamic stability of the columns under periodic transient loadings,the approximate solution method and the Fourier method of the stable periodic solution are adopted w... To study the influence of original defects on the dynamic stability of the columns under periodic transient loadings,the approximate solution method and the Fourier method of the stable periodic solution are adopted while considering the influence of original defects on columns.The dynamic stability of the columns under periodic transient loadings is analyzed theoretically.Through the study of different deflections,the dynamic instability of the columns is obtained by Maple software.The results of theoretical analysis show that the larger the original defects,the greater the unstable area,the stable solution amplitude of columns and the risk of instability caused by parametric resonance will be.The damping of columns is a vital factor in reducing dynamic instability at the same original defects.On the basis of the Mathieu-Hill equation,the relationship between the original defects and deflection is deduced,and the dynamic instability region of the columns under different original defects is obtained.Therefore,reducing the original defects of columns can further enhance the dynamic stability of the compressed columns in practical engineering. 展开更多
关键词 periodic transient loading parametric resonance original defect dynamic stability
下载PDF
Stability of Disclinations in Nematic Liquid Crystals 被引量:3
5
作者 WANG Yu-Sheng YANG Guo-Hong +1 位作者 TIAN Li-Jun DUAN Yi-Shi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第6期993-999,共7页
In the light of C-mapping method and topological current theory, the stability of disclinations around a spherical particle in nematic liquid crystals is studied. We consider two different defect structures around a s... In the light of C-mapping method and topological current theory, the stability of disclinations around a spherical particle in nematic liquid crystals is studied. We consider two different defect structures around a spherical particle: disclination ring and point defect at the north or south pole of the particle. We calculate the free energy of these different defects in the elastic theory. It is pointed out that the total Frank free energy density can be divided into two parts. One is the distorted energy density of director field around the disclinations. The other is the free energy density of disclinations themselves, which is shown to be concentrated at the defect and to be topologically quantized in the unit of (k - k24)π/2. It is shown that in the presence of saddle-splay elasticity a dipole (radial and hyperbolic hedgehog) configuration that accompanies a particle with strong homeotropic anchoring takes the structure of a small disclination ring, not a point defect. 展开更多
关键词 director field topological defect free energy BIFURCATION
下载PDF
Stable ischemic heart disease in the older adults 被引量:5
6
作者 Xuming DAI Jan Busby-Whitehead +1 位作者 Daniel E Forman Karen P Alexander 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2016年第2期109-114,共6页
1 Introduction Ischemic heart disease is caused by atherosclerotic and/or thrombotic obstruction of coronary arteries. Clinical spec- trum of ischemic heart disease expands from asymptomatic atherosclerosis of corona... 1 Introduction Ischemic heart disease is caused by atherosclerotic and/or thrombotic obstruction of coronary arteries. Clinical spec- trum of ischemic heart disease expands from asymptomatic atherosclerosis of coronary arteries to acute coronary syn- dromes (ACS) including unstable angina, acute myocardial infarction (non-ST elevation myocardial infarction and ST elevation myocardial infarction). Stable ischemic heart dis- ease (SIHD) refers to patients with known or suspected SIHD who have no recent or acute changes in their symp- tomatic status, suggesting no active thrombotic process is underway. 展开更多
关键词 AGING Coronary artery disease Older adults Risk assessment Stable ischemic heart disease
下载PDF
Stability analysis of ellipse- like suspen-dome structures with low rise-span ratio
7
作者 丁明珉 罗斌 +2 位作者 陈项南 郭正兴 管东芝 《Journal of Southeast University(English Edition)》 EI CAS 2016年第1期51-57,共7页
To investigate the effects of initial geometric imperfection and material nonlinearity on the stability analysis of the suspen-dome, the steel roof of Jiangsu Culture Sports Center Gymnasium was utilized as a numerica... To investigate the effects of initial geometric imperfection and material nonlinearity on the stability analysis of the suspen-dome, the steel roof of Jiangsu Culture Sports Center Gymnasium was utilized as a numerical model, and modal analyses were performed. Then, linear buckling analysis,geometric nonlinear stability analysis, geometric nonlinear stability analysis with initial imperfection, and double nonlinear analysis considering material nonlinearity and geometric nonlinearity were discussed in detail to compare the stability performance of the ellipse-like suspen-dome and the single-layer reticulated shell. The results showthat the cable-strut system increases the integrity of the suspen-dome, and moderates the sensibility of the single-layer reticulated shell to initial geometric imperfection. However, it has little influence on integral rigidity, fundamental vibration frequencies, linear ultimate live loads, and geometric nonlinear ultimate live loads without initial imperfection. When considering the material nonlinearity and initial imperfection, a significant reduction occurs in the ultimate stability capacities of these two structures. In this case, the suspen-dome with a lowrise-span ratio is sensitive to the initial imperfection and material nonlinearity. In addition, the distribution pattern of live loads significantly influences the instability modes of the structure, and the uniform live load with full span is not always the most dangerous case. 展开更多
关键词 SUSPEN-DOME single-layer reticulated shell ellipselike stability analysis initial geometric imperfection geometric nonlinearity material nonlinearity
下载PDF
Stability Behavior of Plate Girders with Laterally Unbraced Ends
8
作者 Yiyun Zhu Jing Jiang 《Journal of Civil Engineering and Architecture》 2016年第4期391-404,共14页
Stability tests of three plate girders laterally unbraced on both ends, which were scale models of real plate girders in heavy plants for tower-type boilers, are presented and investigated. The applicability of code p... Stability tests of three plate girders laterally unbraced on both ends, which were scale models of real plate girders in heavy plants for tower-type boilers, are presented and investigated. The applicability of code provisions in ANSI/AISC 360-10 about such members is discussed. A nonlinear finite element analysis was carried out, considering the combined effects of plasticity, residual stress and geometrical imperfections, to simulate the stability behavior of the specimens. The reliability of the numerical model was validated by comparisons with experimental results. The results show that stability behavior of plate girders with laterally unbraced ends is widely different from that of typical simply supported thin-walled beams. The structural response is also sensitive to initial geometrical imperfections of this objects. The model is used to improve the mechanical design of transverse stiffeners over the supports. The positive effect and offsetting influence of imperfections of thicker and additional transverse stiffeners on overall stability behavior are highlighted. A few suggestions for design process are also given. 展开更多
关键词 Plate girder lateral-torsional buckling boundary condition numerical modeling
下载PDF
Measuring and evaluating SDG indicators with Big Earth Data 被引量:15
9
作者 Huadong Guo Dong Liang +13 位作者 Zhongchang Sun Fang Chen Xinyuan Wang Junsheng Li Li Zhu Jinhu Bian Yanqiang Wei Lei Huang Yu Chen Dailiang Peng Xiaosong Li Shanlong Lu Jie Liu Zeeshan Shirazi 《Science Bulletin》 SCIE EI CAS CSCD 2022年第17期1792-1801,共10页
The United Nations 2030 Agenda for Sustainable Development provides an important framework for economic,social,and environmental action.A comprehensive indicator system to aid in the systematic implementation and moni... The United Nations 2030 Agenda for Sustainable Development provides an important framework for economic,social,and environmental action.A comprehensive indicator system to aid in the systematic implementation and monitoring of progress toward the Sustainable Development Goals(SDGs)is unfortunately limited in many countries due to lack of data.The availability of a growing amount of multi-source data and rapid advancements in big data methods and infrastructure provide unique opportunities to mitigate these data shortages and develop innovative methodologies for comparatively monitoring SDGs.Big Earth Data,a special class of big data with spatial attributes,holds tremendous potential to facilitate science,technology,and innovation toward implementing SDGs around the world.Several programs and initiatives in China have invested in Big Earth Data infrastructure and capabilities,and have successfully carried out case studies to demonstrate their utility in sustainability science.This paper presents implementations of Big Earth Data in evaluating SDG indicators,including the development of new algorithms,indicator expansion(for SDG 11.4.1)and indicator extension(for SDG 11.3.1),introduction of a biodiversity risk index as a more effective analysis method for SDG 15.5.1,and several new high-quality data products,such as global net ecosystem productivity,high-resolution global mountain green cover index,and endangered species richness.These innovations are used to present a comprehensive analysis of SDGs 2,6,11,13,14,and 15 from 2010 to 2020 in China utilizing Big Earth Data,concluding that all six SDGs are on schedule to be achieved by 2030. 展开更多
关键词 Big Earth Data Big data Sustainable Development Goals(SDGs) Decision support CASEarth Digital Earth
原文传递
Node shift method for stiffness-based optimization of single-layer reticulated shells 被引量:2
10
作者 Chang-yu CUI Bao-shi JIANG You-bao WANG 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2014年第2期97-107,共11页
This paper presents a node shift method to find the optimal distribution of nodes in single-layer reticulated shells. The optimization process searches for the minimum strain energy configuration and this leads to red... This paper presents a node shift method to find the optimal distribution of nodes in single-layer reticulated shells. The optimization process searches for the minimum strain energy configuration and this leads to reduced sensitivity in initial imper- fections. Strain energy sensitivity numbers are derived for free shift and restricted shift where nodes can move freely in the 3D space or have to move within a predefmed surface respectively. Numerical examples demonstrate the efficiency of the proposed approach. It was found that optimized structures achieve higher ultimate load and are less sensitive to imperfections than the initial structure. The configuration of the final structure is closely related to factors like the initial structural configuration, spatial conditions, etc. Based on different initial conditions, architects can be provided with diverse reasonable structures. Furthermore, by amending the defined shapes and nodal distributions, it is possible to improve the mechanical behavior of the structures. 展开更多
关键词 Node shifts Strain energy sensitivity Structural optimization Static stability Imperfection sensitivity
原文传递
Clinical characteristics of acute ischemic syndrome in China 被引量:3
11
作者 Tan HQ +3 位作者 Liang Y Zhu J Liu LS Cronin L 《Chinese Medical Journal》 SCIE CAS CSCD 2002年第8期1123-1126,共4页
OBJECTIVE: To analyse the characteristics and therapies of patients with acute ischemic syndrome in China.  METHODS: This study is part of the international multicentre registry for acute ischemic syndrome. Since Apr... OBJECTIVE: To analyse the characteristics and therapies of patients with acute ischemic syndrome in China.  METHODS: This study is part of the international multicentre registry for acute ischemic syndrome. Since April 1999, the data of patients admitted to designated hospitals with acute ischemic cardiac chest pain were collected by filling in Case Report Forms offered by the Canadian Cardiovascular Collaboration. The main clinica l characteristics and in hospital events of the patients were recorded.  RESULTS: Fifteen hundred and nine cases of acute ischemic syndrome from 34 hospitals nationwide were enrolled in the registry (including unstable angina and non Q-wave myocardial infarction).The mean age of the patients was 62.3. Male dominance (62.2%) was noted. The percentages of patients with chest pain at presentation and abnormal ECG were 47.8% and 89.5%, respectively. The most common clinical diagnosis on admission was unstable angina, accounting for 91.3% of the patients and non Q-wave myocardial infarction (MI), accounting for the other 8.7%. During hospitalization, the following interventions were given: thrombolytic therapy in 50 cases (3.3%), coronary angiography in 528 cases (35.0%), percutaneous transluminal coronary angioplasty (PTCA) in 253 cases (16.8%) and coronary artery bypass graft surgery (CABG) in 62 cases (4.1%). Nitrate (oral or patch ) and anti-platelet therapy were used in 1460 cases (96.8%) and 1441 cases (95.5%), respectively. The incidence of in hospital major events was 18.8%, in cluding 18 deaths (1.2%), with the most common causes being severe arrhythmias and sudden death.  CONCLUSIONS: Patients with acute ischemic syndrome in China have mostly been diagnosed as cases of unstable angina. A relatively high PTCA rate but low CABG rate was noted in China. The most common cause of in hospital death is severe arrhythmias or sudden death. 展开更多
关键词 ADULT Aged Angioplasty Transluminal Percutaneous Coronary China Coronary Angiography Coronary Artery Bypass FEMALE Humans Male Middle Aged Myocardial Ischemia Research Support Non-U.S. Gov't
原文传递
Early fluid loading for septic patients: Any safety limit needed? 被引量:1
12
作者 Yi-Chun Gong Jing-Tao Liu Peng-Lin Ma 《Chinese Journal of Traumatology》 CAS CSCD 2018年第1期1-3,共3页
Early adequate fluid loading was the corner stone of hemodynamic optimization for sepsis and septic shock. Meanwhile, recent recommended protocol for fluid resuscitation was increasingly debated on hemodynamic stabili... Early adequate fluid loading was the corner stone of hemodynamic optimization for sepsis and septic shock. Meanwhile, recent recommended protocol for fluid resuscitation was increasingly debated on hemodynamic stability vs risk of overloading. In recent publications, it was found that a priority was often given to hemodynamic stability rather than organ function alternation in the early fluid resusci- tation of sepsis. However, no safety limits were used at all in most of these reports. In this article, the rationality and safety of early aggressive fluid loading for septic patients were discussed. It was concluded that early aggressive fluid loading improved hemodynamics transitorily, but was probably traded off with a follow-up organ function impairment, such as worsening oxygenation by reduction of lung aeration, in a part of septic patients at least. Thus, a safeguard is needed against unnecessary excessive fluids in early aggressive fluid loading for set)tic patients. 展开更多
关键词 Sepsis Fluid loading Hemodynamic stability Safety
原文传递
Defective MoS_2 electrocatalyst for highly efficient hydrogen evolution through a simple ball-milling method 被引量:4
13
作者 张丽芳 柯小行 +3 位作者 欧刚 魏呵呵 王鲁宁 伍晖 《Science China Materials》 SCIE EI CSCD 2017年第9期849-856,共8页
Molybdenum disulfide(MoS2) has attracted extensive attention as an alternative to replace noble electrocatalysts in the hydrogen evolution reaction(HER). Here, we highlight an efficient and straightforward ball mi... Molybdenum disulfide(MoS2) has attracted extensive attention as an alternative to replace noble electrocatalysts in the hydrogen evolution reaction(HER). Here, we highlight an efficient and straightforward ball milling method,using nanoscale Cu powders as reductant to reduce MoS2 engineering S-vacancies into MoS2 surfaces, to fabricate a defectrich MoS2material(DR-MoS2). The micron-sized DR-MoS2 catalysts exhibit significantly enhanced catalytic activity for HER with an overpotential(at 10 mA cm^-2) of 176 m V in acidic media and 189 m V in basic media, surpassing most of Mo-based catalysts previously reported, especially in basic solution. Meanwhile stability tests confirm the outstanding durability of DR-MoS2 catalysts in both acid and basic electrolytes. This work not only opens a new pathway to implant defects to MoS2, but also provides low-cost alternative for efficient electrocatalytic production of hydrogen in both alkaline and acidic environments. 展开更多
关键词 ELECTROCATALYST hydrogen evolution MOS2 DEFECTS Svacancies
原文传递
Knockdown factor of buckling load for axially compressed cylindrical shells:state of the art and new perspectives 被引量:2
14
作者 Bo Wang Peng Hao +1 位作者 Xiangtao Ma Kuo Tian 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2022年第1期1-18,共18页
Thin-walled structures are commonly utilized in aerospace and aircraft structures,which are prone to buckling under axial compression and extremely sensitive to geometric imperfections.After decades of efforts,it stil... Thin-walled structures are commonly utilized in aerospace and aircraft structures,which are prone to buckling under axial compression and extremely sensitive to geometric imperfections.After decades of efforts,it still remains a challenging issue to accurately predict the lower-bound buckling load due to the impact of geometric imperfections.Up to now,the lower-bound curve in NASA SP-8007 is still widely used as the design criterion of aerospace thin-walled structures,and this series of knockdown factors(KDF)has been proven to be overly conservative with the significant promotion of the manufacturing process.In recent years,several new numerical and experimental methods for determining KDF have been established,which are systematically reviewed in this paper.The Worst Multiple Perturbation Load Approach(WMPLA)is one of the most representative methods to reduce the conservatism of traditional methods in a rational manner.Based on an extensive collection of test data from 1990 to 2020,a new lower-bound curve is approximated to produce a series of improved KDFs.It is evident that these new KDFs have an overall improvement of 0.1-0.3 compared with NASA SP-8007,and the KDF predicted by the WMPLA is very close to the front of the new curve.This may provide some insight into future design guidelines of axially compressed cylindrical shells,which is promising for the lightweight design of large-diameter aerospace structures. 展开更多
关键词 Thin-walled structures Cylindrical shells Imperfection sensitivity Knockdown factor(KDF) Buckling experiment
原文传递
Robust Optimization for the Correlated MIMO Downlink with Imperfect Channel State Information
15
作者 李昊 徐昌庆 《Journal of Shanghai Jiaotong university(Science)》 EI 2009年第2期184-188,共5页
To reduce the performance deterioration induced by imperfect channel state information(CSI) in correlated multiple input multiple output(MIMO) downlink,the linear transmit/receive filters should be optimized to be rob... To reduce the performance deterioration induced by imperfect channel state information(CSI) in correlated multiple input multiple output(MIMO) downlink,the linear transmit/receive filters should be optimized to be robust to imperfect CSI.A sub-optimization algorithm based on minimizing sum MSE conditional on available imperfect CSI estimates subject to a per-user power constraint is proposed.The algorithm adapts the existing MMSE algorithm from uncorrelated single-user MIMO system with perfect CSI to correlated MIMO downlink with imperfect CSI.Simulation shows that the suboptimal algorithm can effectively mitigate the performance loss induced by imperfect CSI and has a good convergence performance.In addition,the effect of spatial correlation on the performance of the proposed algorithm is also simulated. 展开更多
关键词 MIMO downlink channel state information (CSI) spatial correlation
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部