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82篇 您的检索式:作者名="Siming Li"
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1Seismically Induced Slope Instabilities and the Corresponding Treatments:the Case of a Road in the Wenchuan Earthquake Hit Region显示文摘On May 12, 2008, a magnitude 8.0 earthquake hit Wenchuan County, Sichuan Province resulted in great loss of life and properties.Besides, abundant landslides and slope failures were triggered in the most seriously hit areas and caused disastrous damages to infrastructures and public facilities.Moreover, abundant unstable slopes caused by the quake have the potential to cause damages for a considerable long period of time.The variety of these slopes and the corresponding treatments are connected with the topographical and geological conditions of the sites.It is decided to document and identify some of these major slope instabilities caused by the earthquake and their treatments.The paper shows the condition of a road in Dujiangyan through in situ explorations.The case history showed significant implications to the reconstruction of the quake-hit regions and future disaster prevention and management works.LI Xinpo HE Siming 2009Journal of Mountain Science2009,6,1:22
2A Possible Configuration with Motor-generator Pair for Renewable Energy Integration显示文摘High penetration rates of renewable energy will bring stability problems for the future power grid.One of the critical issues is lack of inertia.In this paper,a synchronous motor-generator pair(MGP)system is proposed as a possible solution for renewable energy integration to enhance inertia and improve grid stability.First,feasibility studies of MGP on inertia,damping,efficiency,and cost are presented.Second,an analytical model is established based on its rotor angle relation.An active power control scheme based on voltage phase difference between renewable energy source and grid is then proposed,and state equations of MGP are derived for small signal stability.Next,two experiments are designed and implemented to verify stable operation and active power regulation of the MGP system.A single-machine infinite bus system is tested to investigate small signal stability and frequency response of MGP.The results show that the MGP system has a solid base in physics and is a feasible solution for providing enough inertia and improving small signal performance in the power grid with high penetration of renewable energy.The paper concludes with a discussion on future research directions to gain a better understanding of MGP.Siming Wei Yingkun Zhou Song Li Yongzhang Huang 2017CSEE Journal of Power and Energy Systems2017,3,1:20
3Prevention and treatment technologies of railway tunnel water inrush and mud gushing in China显示文摘Water inrush and mud gushing are one of the biggest hazards in tunnel construction. Unfavorable geological sections can be observed in almost all railway tunnels under construction or to be constructed, and vary in extent. Furthermore, due to the different heights of mountains and the lengths of tunnels, the locations of the unfavorable geological sections cannot be fully determined before construction, which increases the risk of water inrush and mud gushing. Based on numerous cases of water inrush and mud gushing in railway tunnels, the paper tries to classify water inrush and mud gushing in railway tunnels in view of the conditions of the surrounding rocks and meteorological factors associated with tunnel excavation. In addition, the causes of water inrush and mud gushing in combination of macroand micromechanisms are summarized, and site-specifc treatment method is put forward. The treatment methods include choosing a method of advance geological forecast according to risk degrees of different sections in the tunnel, determining the items of predictions, and choosing the appropriate methods, i.e. draining-oriented method, blocking-oriented method or draining-and-blocking method. The treatment technologies of railway water inrush and mud gushing are also summarized, including energy relief and pressure relief technology, advance grouting technology, and advance jet grouting technology associated with their key technical features and applicable conditions. The results in terms of treatment methods can provide reference to the prevention and treatment of tunnel water inrush and mud gushing.Yong Zhao Pengfei Li Siming Tian 2013Journal of Rock Mechanics and Geotechnical Engineering2013,5,6:16
4Single-cell transcriptome analysis of the novel coronavirus (SARS-CoV-2) associated gene ACE2 expression in normal and non-obstructive azoospermia (NOA) human male testes显示文摘Being infected by SARS-CoV-2 may cause damage to multiple organs in patients, such as the lung, liver and heart. Angiotensin-converting enzyme 2(ACE2), reported as a SARS-CoV-2 receptor, is also expressed in human male testes. This suggests a potential risk in human male reproductive system. However, the characteristics of ACE2-positive cells and the expression of other SARS-CoV-2 process-related genes are still worthy of further investigation. Here, we performed singlecell RNA seq(scRNA-seq) analysis on 853 male embryo primordial germ cells(PGCs) and 2,854 normal testis cells to assess the effects of the SARS-CoV-2 virus on the male reproductive system from embryonic stage to adulthood. We also collected and constructed the scRNA-seq library on 228 Sertoli cells from three non-obstructive azoospermia(NOA) patients to assess the effects at disease state. We found that ACE2 expressing cells existed in almost all testis cell types and Sertoli cells had highest expression level and positive cells ratio. Moreover, ACE2 was also expressed in human male PGCs. In adulthood, the level of ACE2 expression decreased with the increase of age. We also found that ACE2 positive cells had high expressions of stress response and immune activation-related genes. Interestingly, some potential SARS-CoV-2 process-related genes such as TMPRSS2, BSG, CTSL and CTSB had different expression patterns in the same cell type. Furthermore, ACE2 expression level in NOA donors’ Sertoli cells was significantly decreased. Our work would help to assess the risk of SARS-CoV-2 infection in the male reproductive system.Xixi Liu Yidong Chen Wenhao Tang Li Zhang Wei Chen Zhiqiang Yan Peng Yuan Ming Yang Siming Kong Liying Yan Jie Qiao 2020Science China(Life Sciences)2020,63,7:14
5Discrete Element Modeling of Debris Avalanche Impact on Retaining Walls显示文摘In China,gravity retaining walls are widely used as protection structures against rockfalls,debris flows and debris avalanches along the roads in mountainous areas.In this paper,the Discrete Element Method(DEM) has been used to investigate the impact of granular avalanches and debris flows on retaining walls.The debris is modeled as two dimensional circular disks that interact through frictional sliding contacts.The basic equations that control the deformation and motion of the particles are introduced.A series of numerical experiments were conducted on an idealized debris slide impacting a retaining wall.The parametric study has been performed to examine the influences of slope geometry,travel distance of the sliding mass,wall position,and surface friction on the impact force exerted on the wall.Results show that:1) the force achieves its maximum value when slope angle is equal to 60°,as it varies from 30° to 75°;2) an approximate linear relationship between the impact force and the storage area length is determined.LI Xinpo HE Siming LUO Yu WU Yong 2010Journal of Mountain Science2010,7,3:12
6Notoginsenoside Ft1 acts as a TGR5 agonist but FXR antagonist to alleviate high fat diet-induced obesity and insulin resistance in mice显示文摘Obesity and its associated complications are highly related to a current public health crisis around the world.A growing body of evidence has indicated that G-protein coupled bile acid(BA) receptor TGR5(also known as Gpbar-1) is a potential drug target to treat obesity and associated metabolic disorders.We have identified notoginsenoside Ftl(Ftl) from Panax notoginseng as an agonist of TGR5 in vitro.However,the pharmacological effects of Ftl on diet-induced obese(DIO) mice and the underlying mechanisms are still elusive.Here we show that Ftl(100 mg/100 diet) increased adipose lipolysis,promoted fat browning in inguinal adipose tissue and induced glucagon-like peptide-1(GLP-1) secretion in the ileum of wild type but not Tgr5^(-/-) obese mice.In addition,Ftl elevated serum free and taurineconjugated bile acids(BAs) by antagonizing Fxr transcriptional activities in the ileum to activate Tgr5 in the adipose tissues.The metabolic benefits of Ftl were abolished in Cyp27 al^(-/-) mice which have much lower BA levels.These results identify Ftl as a single compound with opposite activities on two key BA receptors to alleviate high fat diet-induced obesity and insulin resistance in mice.Lili Ding Qiaoling Yang Eryun Zhang Yangmeng Wang Siming Sun Yingbo Yang Tong Tian Zhengcai Ju Linshan Jiang Xunjiang Wang Zhengtao Wang Wendong Huang Li Yang 2021Acta Pharmaceutica Sinica B2021,11,6:10
7Study on the Rainfall and Aftershock Threshold for Debris Flow of Post-earthquake显示文摘Due to the special condition of provenance and disaster environment after '5·12' Earthquake, the probability and conditions of the occurrence of gully debris flow change greatly after the event, which make it difficult to prevent disaster effectively. In this study the hydrological model of ground water table in loose sediment is established. According to infinite slope theory, the safety factor of deposits is defined as the ratio of resistance force to driving force. The starting condition of post-earthquake gully debris flow is clearly studied by analyzing the effects of rainfall intensity, seismic strength, slope gradient and mechanical properties on the balance of accumulation body. Then the formulas of rainfall and aftershock threshold for starting of gully debris flow are proposed, and an example is given to illustrate the effect of rainfall, aftershocks and their coupling action on a debris flow. The result shows the critical rainfall intensity decreases as the lateral seismic acceleration and channel gradient increases, while the critical intensity linearly increases as the friction angle increases.HE Siming LI Dexin WU Yong LUO Yu 2011Journal of Mountain Science2011,8,5:7
8Artemisinin mimics calorie restriction to extend yeast lifespan via a dual-phase mode: a conclusion drawn from global transcriptome profiling显示文摘Calorie restriction(CR) promotes longevity among distinct organisms from yeast to mammals. Although CR-prolonged lifespan is believed to associate with enhanced respiratory activity, it is apparently controversial for accelerated energy consumption regardless of insufficient nutrient intake. In reconciling the contradiction of less food supply versus much metabolite dispense, we revealed a CR-based mode of dual-phase responses that encompass a phase of mitochondrial enhancement(ME) and a phase of post-mitochondrial enhancement(PME), which can be distinguished by the expression patterns and activity dynamics of mitochondrial signatures. ME is characterized by global antioxidative activation, and PME is denoted by systemic metabolic modulation. CR-mediated aging-delaying effects are replicated by artesunate, a semi-synthetic derivative of the antimalarial artemisinin that can alkylate heme-containing proteins, suggesting artesunate-heme conjugation functionally resembles nitric oxide-heme interaction. A correlation of artesunate-heme conjugation with cytochrome c oxidase activation has been established from adduct formation and activity alteration. Exogenous hydrogen peroxide also mimics CR to trigger antioxidant responses, affect signaling cascades, and alter respiratory rhythms, implying hydrogen peroxide is engaged in lifespan extension. Conclusively, artesunate mimics CR-triggered nitric oxide and hydrogen peroxide to induce antioxidative networks for scavenging reactive oxygen species and mitigating oxidative stress, thereby directing metabolic conversion from anabolism to catabolism, maintaining essential metabolic functionality, and extending life expectancy in yeast.WANG DaTing WU Ming LI SiMing GAO Qian ZENG QingPing 2015Science China(Life Sciences)2015,58,5:6
9Understanding the improved performance of sulfur-doped interconnected carbon microspheres for Na-ion storage显示文摘As one of the low-cost energy storage systems,Na-ion batteries(NIBs)have received tremendous attention.However,the performance of current anode materials still cannot meet the requirements of NIBs.In our work,we obtain sulfur-doped interconnected carbon microspheres(S-CSs)via a simple hydrothermal method and subsequent sulfurizing treatment.Our S-CSs exhibit an ultrahigh reversible capacity of 520 mAh g^(-1) at 100 mA g^(-1) after 50 cycles and an excellent rate capability of 257 mAh g^(-1),even at a high current density of 2 A g^(-1).The density functional theory calculations demonstrate that sulfur doping in carbon favors the adsorption of Na atom during the sodiation process,which is accountable for the performance enhancement.Furthermore,we also utilize operando Raman spectroscopy to analyze the electrochemical reaction of our S-CSs,which further highlights the sulfur doping in improving Na-ion storage performance.Xinran Yuan Siming Chen Jinliang Li Junpeng Xie Genghua Yan Botian Liu Xibo Li Rui Li Likun Pan Wenjie Mai 2021Carbon Energy2021,3,4:3
10High performance CuO-CeO_2 catalysts for selective oxidation of CO in excess hydrogen:Effect of hydrothermal preparation conditions显示文摘High performance CuO-CeO2 catalysts for selective oxidation of CO in excess hydrogen were prepared by a hydrothermal method under different preparation conditions and evaluated for catalytic activities and selectivities.By changing the nCTAB/nCe ratio and hydrothermal aging time,the catalytic activity of the CuO-CeO2 catalysts increased and the operating temperature window,in which the CO conversion was higher than 99%,was widened.XRD results showed no peaks of CuOx species and Cu-Ce-O solid solution were observed.On the other hand,Cu+ species in the CuO-CeO2 catalysts,which was associated with a strong interaction between copper oxide clusters and cerium oxide and could be favorable for improving the selective oxidation performance of CO in excess H2,were detected by H2-TPR and XPS techniques.Pengfei Zhu Jing Li Qinqin Huang Siming Yan Mei Liu Renxian Zhou 2009Journal of Natural Gas Chemistry2009,18,3:2
11Failure Mechanisms of Post-Earthquake Bedrock Landslides in Response to Rainfall Infiltration显示文摘Among the triggering factors of post-earthquake bedrock landslides,rainfall plays an important role.However,with slope variation,the mechanism of its effects on the failure of rock landslides is not clear.Here,from the viewpoint of fracture mechanics,and based on post-earthquake conditions,the mechanisms of crack propagation,water infiltration and development of the sliding surface were investigated.Then,according to the upper boundary theorem,the effects of water infiltrated into fractures on the stability of rock slopes were analyzed quantitatively.Finally,an example is presented to verify the theory.The results show that the propagation and coalescence of cracks and the lubrication of incipient sliding surfaces are the main causes of the failure of post-earthquake rock landslides in response to rainfall.WU Yong HE Siming LUO Yu LI Xinpo 2011Journal of Mountain Science2011,8,1:2
12Stiffness-mediated mesenchymal stem cell fate decision in 3D-bioprinted hydrogels显示文摘Background:Hydrogels with tuneable mechanical properties are an attractive material platform for 3D bioprinting.Thus far,numerous studies have confirmed that the biophysical cues of hydrogels,such as stiffness,are known to have a profound impact on mesenchymal stem cell(MSC)differentiation;however,their differentiation potential within 3D-bioprinted hydrogels is not completely understood.Here,we propose a protocol for the exploration of how the stiffness of alginate–gelatin(Alg-Gel)composite hydrogels(the widely used bioink)affects the differentiation of MSCs in the presence or absence of differentiation inducing factors.Methods:Two types of Alg-Gel composite hydrogels(Young’s modulus:50 kPa vs.225 kPa)were bioprinted independently of porosity.Then,stiffness-induced biases towards adipogenic and osteogenic differentiation of the embedded MSCs were analysed by co-staining with alkaline phosphatase(ALP)and oil red O.The expression of specific markers at the gene level was detected after a 3-day culture.Results:Confocal microscopy indicated that all tested hydrogels supported MSC growth and viability during the culture period.Higher expression of adipogenic and osteogenic markers(ALP and lipoprotein lipase(LPL))in stiffer 3D-bioprinted matrices demonstrated a more significant response of MSCs to stiffer hydrogels with respect to differentiation,which was more robust in differentiation-inducing medium.However,the LPL expression in stiffer 3D-bioprinted constructs was reduced at day 3 regardless of the presence of differentiation-inducing factors.Although MSCs embedded in softer hydrogels to some extent proceeded toward adipogenic and osteogenic lineages within a few days,their differentiation seemed to be slower and more limited.Interestingly,the hydrogel itself(without differentiation-inducing factors)exhibited a slight effect on whether MSCs differentiated towards an adipogenic or an osteogenic fate.Considering that the mechanoregulated protein Yes-associated protein(YAP)is involved in MSC fate decisions,we further found that inhibition of YAP significantly downregulated the expression of ALP and LPL in MSCs in stiffer constructs regardless of the induced growth factors present.Conclusions:These results demonstrate that the differentiation of MSCs in 3D-bioprinted matrices is dependent on hydrogel stiffness,which emphasizes the importance of biophysical cues as a determinant of cellular behaviour.Yufan Liu Zhao Li Jianjun Li Siming Yang Yijie Zhang Bin Yao Wei Song Xiaobing Fu Sha Huang 2020Burns & Trauma2020,8,1:2
13Housing tenure and residential mobility in urban China: a study of commodity housing development in Beijing and Guangzhou显示文摘Li SiMing 2003Urban Affair Review2003,,38:1
14Housing preferences in a transitional housing system, the case of Beiiing, China显示文摘Wang Donggen Li Siming 2004Environment and Planning2004,,36:1
15Impact of the national trunk highway system on accessibility in China显示文摘Li Siming Shun Yiman 2001Journal of Transport Geography2001,,9:1
16Impacts of the National TrunkHighway System on Accessibility in China显示文摘Li Siming Shum Yiman 2001Journal ofTransport Geography2001,,9:1
17Urban Hous Change显示文摘Li Siming Huang Youqin 2006Housing Studies2006,,5:1
18Contextualizing of Residential Mobility and Housing Choice:Evidence from Urban China显示文摘Siming Li Fulong Wu 2004Environment and Planning A2004,36,1:1
19The Housing Market and Tenure Decisions in Chinese Cities:a Muliti-variarate Analysis of the Case of Guangzhou显示文摘Siming Li 2000Housing Studies2000,15,2:1
20Impacts of the national trunk highway system on accessibility in China 显示文摘Li Siming Shum Yiman 2001Journal of Transport Geog- raphy2001,9,1:1
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