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314篇 您的检索式:作者名="Weimin Yang"
    题名 作者 年代 出处 被引量
1Spatio-temporal dynamics of vegetation and its relationship with climate factors Mongolia, China coverage in Inner显示文摘The vegetation coverage dynamics and its relationship with climate factors on different spatial and temporal scales in Inner Mongolia during 2001-2010 were analyzed based on MODIS-NDVI data and climate data.The results indicated that vegetation coverage in Inner Mongolia showed obvious longitudinal zonality,increasing from west to east across the region with a change rate of 0.2/10°N.During 2001-2010,the mean vegetation coverage was 0.57,0.4 and 0.16 in forest,grassland and desert biome,respectively,exhibiting evident spatial heterogeneities.Totally,vegetation coverage had a slight increasing trend during the study period.Across Inner Mongolia,the area of which the vegetation coverage showed extremely significant and significant increase accounted for 11.25% and 29.13% of the area of whole region,respectively,while the area of which the vegetation coverage showed extremely significant and significant decrease accounted for 7.65% and 26.61%,respectively.On inter-annual time scale,precipitation was the dominant driving force of vegetation coverage for the whole region.On inter-monthly scale,the change of vegetation coverage was consistent with both the change of temperature and precipitation,implying that the vegetation growth within a year is more sensitive to the combined effects of water and heat rather than either single climate factor.The vegetation coverage in forest biome was mainly driven by temperature on both inter-annual and inter-monthly scales,while that in desert biome was mainly influenced by precipitation on both the two temporal scales.In grassland biome,the yearly vegetation coverage had a better correlation with precipitation,while the monthly vegetation coverage was influenced by both temperature and precipitation.In grassland biome,the impacts of precipitation on monthly vegetation coverage showed time-delay effects.MU Shaojie YANG Hongfei LI Jianlong CHEN Yizhao GANG Chengcheng ZHOU Wei JU Weimin 2013Journal of Geographical Sciences2013,23,2:28
2Altered trends in carbon uptake in China’s terrestrial ecosystems under the enhanced summer monsoon and warming hiatus显示文摘The carbon budgets in terrestrial ecosystems in China are strongly coupled with climate changes.Over the past decade,China has experienced dramatic climate changes characterized by enhanced summer monsoon and decelerated warming.However,the changes in the trends of terrestrial net ecosystem production(NEP)in China under climate changes are not well documented.Here,we used three ecosystem models to simulate the spatiotemporal variations in China's NEP during 1982–2010 and quantify the contribution of the strengthened summer monsoon and warming hiatus to the NEP variations in four distinct climatic regions of the country.Our results revealed a decadal-scale shift in NEP from a downtrend of–5.95 Tg C/yr^2(reduced sink)during 1982–2000 to an uptrend of 14.22 Tg C/yr^2(enhanced sink)during 2000–10.This shift was essentially induced by the strengthened summer monsoon,which stimulated carbon uptake,and the warming hiatus,which lessened the decrease in the NEP trend.Compared to the contribution of 56.3%by the climate effect,atmospheric CO2 concentration and nitrogen deposition had relatively small contributions(8.6 and 11.3%,respectively)to the shift.In conclusion,within the context of the global-warming hiatus,the strengthening of the summer monsoon is a critical climate factor that enhances carbon uptake in China due to the asymmetric response of photosynthesis and respiration.Our study not only revealed the shift in ecosystem carbon sequestration in China in recent decades,but also provides some insight for understanding ecosystem carbon dynamics in other monsoonal areas.Honglin He Shaoqiang Wang Li Zhang Junbang Wang Xiaoli Ren Lei Zhou Shilong Piao Hao Yan Weimin Ju Fengxue Gu Shiyong Yu Yuanhe Yang Miaomiao Wang Zhongen Niu Rcmg Ge Huimin Yan Mei Huang Guoyi Zhou Yongfei Bai Zongqiang Xie Zhiyao Tang Bingfang Wu Leiming Zhang Nianpeng He Qiufeng Wang Guirui Yu 2019National Science Review2019,6,3:24
3Effect of Pouring Process on the Microstructures of Semi-Solid AlSi_7Mg Alloy显示文摘The effect of different pouring temperatures and different pouring heights, the distance between the mouth of the pouring ladle and the top of the mold, on the microstructure of AlSi7Mg alloy have been researched in the paper. When the pouring temperature is close to the liquidus temperature, the primary α-Al in the billets of AlSi7Mg alloy solidified into spherical and nodular fine grains distributed homogeneously. The optimum pouring temperature for semi-solid AlSi7Mg billet with spherical or nodular primary α-Al is 615℃. At the same pouring temperature, the higher the pouring ladle, the more easily the spherical and nodular primary α-Al obtained in the semi-solid AlSi7Mg billet. When the pouring temperature is close to the liquidus temperature and the pouring ladle is relatively high, it is the great cooling rate, the flow of the molten alloy caused by pouring and the large simultaneous solidification region induced by the near liquidus temperature, that promote the formation of spherical or nodular primary α-Al.Weimin MAO, Chenglin CUT, Aimin ZHAO, Jilian YANG and Xueyou ZHONG Foundry Institute, University of Science and Technology Beijing, Beijing 100083, China 2001Journal of Materials Science & Technology2001,17,6:17
4Analysis of Micro-texture during Secondary Recrystallization in a Hi-B Electrical Steel显示文摘The understanding of Goss texture in Hi-B electrical steels possesses significant industrial and academic value, thus attracts worldwide attention. The prevailing models for sharp Goss texture formation during secondary recrystallization are CSL (coincident site lattice) boundary theory and HE (high energy) boundary theory. These theories stress the key factor of preferred growth and the difference between them only lies in the specific selection manner. This work examined the texture gradient in primarily recrystallized sheet and demonstrated its possible influence on the formation of secondary grains, and then determined the micro- texture during different stages of secondary recrystallization using EBSD (electron back-scattered diffraction) technique, finally analyzed a special type of secondary grains with near Brass orientation, which were detected in the later stage of secondary recrystallization, and discussed its origin and effect in terms of surface energy effect. The results indicate that texture gradient in primarily recrystallized sheet will lead to a multi-stage formation of Goss texture, namely, early stage of secondary grains with various orientations in subsurface region, intermediate stage of preferred growth of Goss grains into center layer and re-grow back to the surface and the final stage of Goss grain growth by swallowing slowly the island grains with the help of H2 atmosphere.Mengqi Yan Hao Qian Ping Yang Weimin Mao Qiwu Jian Wenxu Jin 2011Journal of Materials Science & Technology2011,27,11:16
5Reversal of B-cell hyperactivation and functional impairment is associated with HBsAg seroconversion in chronic hepatitis B patients显示文摘B 房间对再感染在肝炎 B 病毒(HBV ) 和保护的清理起一个重要作用。然而,与长期的 HBV 感染的结果被联系的这些房间的功能的特征仍然保持未知。我们包括地在不同阶段从 CHB 病人调查了外部 B 房间子集的频率,显型,和功能:有免疫力的忍耐(信息技术) ,有免疫力的激活(IA ) ,有免疫力的清理(IC ) ,有 HBsAg seroconversion 的应答者(解决的病人, RP ) ,并且健康控制(HC ) 。IA 病人与另外的组相比显示了外部血记忆 B 房间的更低的百分比。B 房间的全面 polyclonal 激活,由激活标记和 IgG 和 IgM 的分泌物的高水平显示了,在 IA 病人被观察。这 B 房间 hyperactivation 能被增加的 IFN-α 导致;并且在 IA 病人的可溶的 CD40 ligands。尤其是,合作激发器分子 CD80 和浆液 HBsAb 的表示和 HBsAg 特定的 B 房间的频率显著地与 HC 题目相比在信息技术, IA,和 IC 病人被减少。更重要地, B 房间 hyperactivation, co-stimulatory 分子 downregulation 和 HBsAg 特定的 B 房间缺陷在 RP 病人被颠倒。B 房间 hyperactivation 和功能的缺陷的颠倒在长期的肝炎 B 病人与 HBsAg seroconversion 被联系。Xiangsheng Xu Qinghua Shang Xinyue Chen Weimin Nie Zhengsheng Zou Ang Huang Ming Meng Lei Jin Ruonan Xu Ji-Yuan Zhang Junliang Fu Lifeng Wang Zirong Tang Yunbo Xie Xiaoming Yang Zheng Zhang Fu-Sheng Wang 2015Cellular & Molecular Immunology2015,12,3:15
6Structural insights into a novel histone demethylase PHF8显示文摘histone methylation/demethylation 的动态规定在开发期间起一个重要作用。在人的植物 homeodomain (哲学博士) 的变化和截断摸蛋白质 8 (PHF8 ) 与 X 连接智力迟钝和面部异例被联系,例如一张长脸,宽广鼻音尖端,劈开 lip/cleft 腭和大手,然而,它的分子的功能和结构的基础仍然保持不清楚。这里,我们在高分辨率报导 PHF8 的催化核心的水晶结构与或没有伪 - ketoglutarate (伪 - KG ) 。生物化学、结构的研究表明 PHF8 是为甲醇化物 di 、单音甲醇化物的 histone H3 离氨酸 9,然而并非为 H3K9me3 特定的新奇 histone demethylase (H3K9me2/1 ) 。我们的分析也揭示人的 PHF8 怎么在 methylation 状态之间区别并且为 methylated H3K9 完成顺序特性。在里面 vitro demethylation 试金也证明在临床的病人观察的 F279S 异种不拥有 demethylation 活动,建议酶的活动的那损失为 PHF8 病人的致病是关键的。一起拿,这些结果将使位于联系 PHF8 的发展、神经病学的疾病下面的分子的机制清楚些。Lin Yu Yang wang Shuo Huang Jianjun Wang Zengqin Deng Qi Zhang Wei Wu Xingliang Zhang Zhao Liu Weimin Gong Zhongzhou Chen 2010Cell Research2010,20,2:11
7Enhancement of acellular cartilage matrix scaffold by Wharton’s jelly mesenchymal stem cell-derived exosomes to promote osteochondral regeneration显示文摘Articular cartilage defect repair is a problem that has long plagued clinicians.Although mesenchymal stem cells(MSCs)have the potential to regenerate articular cartilage,they also have many limitations.Recent studies have found that MSC-derived exosomes(MSC-Exos)play an important role in tissue regeneration.The purpose of this study was to verify whether MSC-Exos can enhance the reparative effect of the acellular cartilage extracellular matrix(ACECM)scaffold and to explore the underlying mechanism.The results of in vitro experiments show that human umbilical cord Wharton’s jelly MSC-Exos(hWJMSC-Exos)can promote the migration and proliferation of bone marrow-derived MSCs(BMSCs)and the proliferation of chondrocytes.We also found that hWJMSC-Exos can promote the polarization of macrophages toward the M2 phenotype.The results of a rabbit knee osteochondral defect repair model confirmed that hWJMSC-Exos can enhance the effect of the ACECM scaffold and promote osteochondral regeneration.We demonstrated that hWJMSC-Exos can regulate the microenvironment of the articular cavity using a rat knee joint osteochondral defect model.This effect was mainly manifested in promoting the polarization of macrophages toward the M2 phenotype and inhibiting the inflammatory response,which may be a promoting factor for osteochondral regeneration.In addition,microRNA(miRNA)sequencing confirmed that hWJMSC-Exos contain many miRNAs that can promote the regeneration of hyaline cartilage.We further clarified the role of hWJMSC-Exos in osteochondral regeneration through target gene prediction and pathway enrichment analysis.In summary,this study confirms that hWJMSC-Exos can enhance the effect of the ACECM scaffold and promote osteochondral regeneration.Shuangpeng Jiang Guangzhao Tian Zhen Yang Xiang Gao Fuxin Wang Juntan Li Zhuang Tian Bo Huang Fu Wei Xinyu Sang Liuqi Shao Jian Zhou Zhenyong Wang Shuyun Liu Xiang Sui Quanyi Guo Weimin Guo Xu Li 2021Bioactive Materials2021,6,9:11
8Microstructure characteristics and mechanical properties of rheocasting 7075 aluminum alloy显示文摘The microstructure characteristics and mechanical properties of 7075 aluminum alloy produced by a new rheoforming technique,under as-cast and optimized heat treatment conditions,were investigated.The present rheoforming combined the innovatively developed rheocasting process,named as ICSPC(inverted coneshaped pouring channel)process,and the existing HPDC(high pressure die casting)process.The experimental results show that the ICSPC can be used to prepare high quality semi-solid slurry for the subsequent die casting.Compared with conventional HPDC process,the ICSPC process can improve the microstructures and mechanical properties of the cast tensile samples.An optimized heat treatment results in significant improvement in ultimate tensile strength.However,the ductility of the samples,both under as-cast and optimized heat treatment conditions,are relatively poor.Yang Bin Mao Weimin Song Xiaojun 2013China Foundry2013,10,5:8
9Clopidogrel loading dose versus maintenance dose to treat patients with acute ischaemic stroke in China(CLASS-China):results from a prospective double-blind randomised clinical trial显示文摘Aim The role of clopidogrel in treating patients with acute ischaemic stroke is unclear.We have conducted the clinical trial in order to evaluate the efficacy and safety of clopidogrel with a loading dose in treating patients with non-cardiogenic acute ischaemic stroke.Method Clopidogrel loading dose versus maintenance dose to treat patients with acute ischaemic stroke in China(CLASS-China)was a prospective,randomised,double-blind and placebo-controlled clinical trial in China.Patients with acute ischaemic stroke of non-cardiogenic origin within 48 hours of onset were enrolled and those received thrombolysis were excluded.Enrolled patients were divided into two treatment groups:loading dose and routine dose.The primary outcome was the incidence of stroke recurrence or progression within 7 days.Primary safety outcome was measured by life-threatening haemorrhage.An intent-to-treat analysis was used for the statistical analysis.results From March 2008 to March 2010,a total of 303 patients from 16 centres were recruited into this study;six were excluded because of lack of basic information.Since the enrolment was slow and the study drug expired in March 2010,this clinical trial was stopped earlier than planned.No significant baseline and demographic differences were seen between the two groups.There was no difference in primary outcome between the loading dosage group 16.1%(24/149)and control group 14.9%(22/148),respectively(p=0.782).The mortality and disability rate within 90 days in loading dose group(19.6%)was slightly lower than that in controlled group(23.4%),p=0.444.Loading dose group had two(1.3%)cases of fatal haemorrhage and control group had four(2.7%)within 90 days,p=0.674.No significant difference was detected in other adverse events between the groups.conclusion In our study stopped early due to slow enrolment,loading dose of clopidogrel does not reduce the risk of recurrent stroke.Future trials with sufficient number of patients enrolled are needed to re-examine this hypothesis.Ying Zhao Wanyong Yang Zefeng Tan Wenmin Wang Weimin Xiao Jinsheng Zeng Anding Xu 2017Stroke & Vascular Neurology2017,2,3:7
10Newborn screening with targeted sequencing:a multicenter investigation and a pilot clinical study in China显示文摘Different newborn screening(NBS) programs have been practiced in many countries since the 1960 s. It is of considerable interest whether next-generation sequencing is applicable in NBS. We have developed a panel of 465 causative genes for 596 early-onset, relatively high incidence, and potentially actionable severe inherited diseases in our Newborn Screening with Targeted Sequencing(NESTS) program to screen 11,484 babies in 8 Women and Children’s hospitals nationwide in China retrospectively. The positive rate from preliminary screening of NESTS was 7.85%(902/11,484). With 45.89%(414/902) follow-up of preliminary positive cases, the overall clinically confirmative diagnosis rate of monogenic disorders was 12.07%(50/414), estimating an average of 0.95%(7.85% × 12.07%) clinical diagnosis rate, suggesting that monogenic disorders account for a considerable proportion of birth defects. The disease/gene spectrum varied in different regions of China. NESTS was implemented in a hospital by screening 3923 newborns to evaluate its clinical application. The turn-around time of a primary report, including the sequencing period of < 7 days, was within 11 days by our automatic interpretation pipeline. Our results suggest that NESTS is feasible and cost-effective as a first-tier NBS program, which will change the status of current clinical practice of NBS in China.Chanjuan Hao Ruolan Guo Xuyun Hu Zhan Qi Qi Guo Xuanshi Liu Yuanhu Liu Yanhua Sun Xiaofen Zhang Feng Jin Xiujie Wu Ren Cai Dingyuan Zeng Xijiang Hu Xiaohua Wang Xiaoping Ji Wenjie Li Quansheng Xing Lanfang Mu Xiulian Jiang Xue Yang Weimin Yang Yan Zhang Qianli Yin Xin Ni Wei Li 2022Journal of Genetics and Genomics2022,49,1:7
11Peripheral CD4^(+) T cell signatures in predicting the responses to anti-PD-1/PD-L1 monotherapy for Chinese advanced non-small cell lung cancer显示文摘Limited benefit population of immune checkpoint inhibitors makes it urgent to screen predictive biomarkers for stratifying the patients.Herein,we have investigated peripheral CD4^(+) T cell signatures in advanced non-small cell lung cancer(NSCLC)patients receiving anti-PD-1/PD-L1 treatments.It was found that the percentages of IFN-γand IL-17A secreting naïve CD4^(+) T cells(Tn),and memory CD4^(+) T cells(Tm)expressing PD-1,PD-L1 and CTLA-4 were significantly higher in responder(R)than non-responder(NonR)NSCLC patients associated with a longer progression free survival(PFS).Logistic regression analysis revealed that the baseline IFN-γ-producing CD4^(+) Tn cells and PD-1^(+)CD4^(+) Tm cells were the most significant signatures with the area under curve(AUC)value reaching 0.849.This was further validated in another anti-PD-1 monotherapy cohort.Conversely,high percentage of CTLA-4^(+)CD4^(+) Tm cells was associated with a shorter PFS in patients receiving anti-PD-L1 monotherapy.Our study therefore elucidates the significance of functional CD4^(+) Tn and Tm subpopulations before the treatment in predicting the responses to anti-PD-1 treatment in Chinese NSCLC patients.The fact that there display distinct CD4^(+) T cell signatures in the prediction to anti-PD-1 and anti-PD-L1 monotherapy from our study provides preliminary evidence on the feasibility of anti-PD-1 and anti-PD-L1 combination therapy for advanced NSCLC patients.Liliang Xia Hui Wang Mingjiao Sun Yi Yang Chengcheng Yao Sheng He Huangqi Duan Weimin Xia Ruiming Sun Yaxian Yao Zhiwei Chen Qiong Zhao Hong Li Shun Lu Ying Wang 2021Science China(Life Sciences)2021,64,10:7
12Microstructure Study on Semi-solid 60Si2Mn during Compressing显示文摘The microstructure behavior and deformation mechanism of semi-solid 60Si2Mn fabricated by electromagnetic stirring under different deformation conditions during thixoforming are studied by means of Gleeble-1500 thermal-strain-stress simulator. The micro- structure of deformed 60Si2Mn and that of the non-deformed are compared. The results show that the grain size within deformation zone decreases as the amount of deformation increases or deformation temperature decreases, but deformation fate has small effect on grain size when the rate is very low. Besides, there is a critical amount of deformation to reduce grain size. These results offer theoretical and experimental basis for further producing semi-solid material with high melting temperature and direct forming of semi-solid slurry.Yonglin Kang, Xiongfei Yang, Renbo Song, Weimin Mao, Maosheng Yang (Material Science & Engineering School, University of Science and Technology Beijing, Beijing 100083, China) 2001Journal of University of Science and Technology Beijing2001,8,2:7
13Distribution of Microelements and Their Influence on the Corrosion Behavior of Aluminum Foil显示文摘The distribution of microelement Fe, Si, Cu and Mg in the surface layer of aluminum foil annealed at 300℃ and 500℃ were determined by secondary ion mass spectrometer. The corrosion structure produced by electrochemical etching was also observed. It was found that the Mg concentration at external surface was increased exponentially over the fourth degree and promoted by higher annealing temperature, which will increase the number of corrosion pits inside the large grains, and therefore the specific capacity of the foils for electrolytic capacitors. The similar effects of microelement Fe, Si and Cu were not so strong.Weimin MAO, Heng JIANG, Ping YANG, Huiping FENG and Yongning YUDepartment of Materials, University of Science and Technology Beijing, Beijing 100083, ChinaProf., Ph.D., 2005Journal of Materials Science & Technology2005,21,1:7
14Tribological Behavior of Al CoCrFeNi(Ti_(0.5))High Entropy Alloys under Oil and MACs Lubrication显示文摘The tribological properties of AlCoCrFeNi and AlCoCrFeNiTi_(0.5) high entropy alloys under gear oil and multiply alkylated cyclopentanes(MACs)lubrication condition have been studied.The equiaxed crystal structure of AlCoCrFeNi alloy is obtained after heat-treatment.The AlCoCrFeNiTi_(0.5) alloy keeps dendrite structure.Under the gear oil with good lubrication action,AlCoCrFeNiTi_(0.5) alloy preserves better tribological properties than AlCoCrFeNi alloy.The delamination and crack behaviors tend to occur in the grain boundary of AlCoCrFeNi alloy and along the interdendrite region of AlCoCrFeNiTi_(0.5) alloy.Under the MACs with relatively poor lubrication action,the applied load slightly influences the wear behavior of AlCoCrFeNi alloy,but seriously impacts the wear mechanism of AlCoCrFeNiTi_(0.5) alloy.Compared with AlCoCrFeNi alloy,AlCoCrFeNiTi_(0.5) alloy keeps better wear-resistance at low applied load of 100 N,but preserves less wearresistance at high applied load of 200 N.Yuan Yu Jun Wang Jinshan Li Jun Yang Hongchao Kou Weimin Liu 2016Journal of Materials Science & Technology2016,32,5:6
15Quantum network communication: a discrete-time quantum-walk approach显示文摘We study the problem of quantum multi-unicast communication over the butterfly network in a quantum-walk architecture, where multiple arbitrary single-qubit states are transmitted simultaneously between multiple source-sink pairs. Here, by introducing quantum walks, we demonstrate a quantum multiunicast communication scheme over the butterfly network and the inverted crown network, respectively,where the arbitrary single-qubit states can be efficiently transferred with both the probability and the state fidelity one. The presented result concerns only the butterfly network and the inverted crown network, but our techniques can be applied to a more general graph. It paves a way to combine quantum computation and quantum network communication.Yuguang YANG Jiajie YANG Yihua ZHOU Weimin SHI Xiubo CHEN Jian LI Huijuan ZUO 2018Science China(Information Sciences)2018,61,4:5
16Systematic review of risk factors for progressive ischemic stroke显示文摘OBJECTIVE: To determine the risk factors for progressive ischemic stroke, and to prevent onset and make a prognosis of disease, the present study systemically evaluated 19 cohort studies and 10 case-controlled studies of progressive ischemic stroke. SEARCH STRATEGY: A computer-based, online, literature search of PubMed (1966/2007), China Biological Medicine Database (CBM-disc, 1979/2007) and CNKI (www.cnki.net, 1979/2007) was performed to screen for related studies. DATA SELECTION: Cohort or case-controlled studies that focused on risk factors of progressive ischemic stroke were selected for review. Two reviewers independently extracted data and as-sessed study quality according to Cochrane Collaboration guidelines. Statistical analysis was per-formed using RevMan software. MAIN OUTCOME MEASUREMENT: Risk factors for progressive ischemic stroke. RESULTS: Using the inclusion criteria, 29/781 studies published in English and Chinese were ini-tially reviewed, including 19 cohort studies and 10 case-control studies. Despite variations in de-termination of progressive ischemic stroke and the intervals between 2 evaluations, all studies de-scribed the diagnostic criteria for progressive ischemic stroke. Logistic analysis was employed in 20 of the studies. Meta-analysis of primary data in the related studies determined that the following factors that significantly correlated with progressive ischemic stroke: fever [risk ratio (RR) = 2.26, 95% confidence interval (CI): 1.20–4.26, P = 0.01; odds ratio (OR) = 2.85, 95% CI: 1.64–4.98, P < 0.01)]; diabetes (RR = 1.38, 95% CI: 1.18–1.61, P < 0.01; OR = 2.48, 95% CI: 1.93–3.19, P < 0.01); coronary heart disease (RR = 1.22, 95% CI: 1.08–1.38, P < 0.01); neuroimaging transformation (RR = 1.55, 95%CI: 1.34–1.80, P < 0.01; OR = 2.29, 95% CI: 1.47–3.58, P < 0.01); and hypergly-cemia (RR = 2.62, 95% CI: 1.86–3.68, P < 0.01; OR = 3.49, 95% CI: 1.92–6.35, P < 0.01). CONCLUSION: Fever, diabetes, coronary heart disease, neuroimaging transformation, and hyper-glycemia are important risk factors for progressive ischemic stroke. Interventions for these risk fac-tors could effectively prevent occurrence of progressive ischemic stroke.Weimin Yang Fanyi Kong Ming Liu Zilong Hao 2011Neural Regeneration Research2011,6,5:5
17Disentangling the factors that contribute to variation in forest biomass increments in the mid-subtropical forests of China显示文摘Mid-subtropical forests are the main vegetation type of global terrestrial biomes, and are critical for maintaining the global carbon balance. However, estimates of forest biomass increment in mid-subtropical forests remain highly uncertain. It is critically important to determine the relative importance of different biotic and abiotic factors between plants and soil, particularly with respect to their influence on plant regrowth. Consequently,it is necessary to quantitatively characterize the dynamicspatiotemporal distribution of forest carbon sinks at a regional scale. This study used a large, long-term dataset in a boosted regression tree(BRT) model to determine the major components that quantitatively control forest biomass increments in a mid-subtropical forested region(Wuyishan National Nature Reserve, China). Long-term,stand-level data were used to derive the forest biomass increment, with the BRT model being applied to quantify the relative contributions of various biotic and abiotic variables to forest biomass increment. Our data show that total biomass(t) increased from 4.62 9 106 to 5.30 9 106 t between 1988 and 2010, and that the mean biomass increased from 80.19 ± 0.39 t ha-1(mean ± standard error) to 94.33 ± 0.41 t ha-1in the study region. The major factors that controlled biomass(in decreasing order of importance) were the stand, topography, and soil. Stand density was initially the most important stand factor, while elevation was the most important topographic factor. Soil factors were important for forest biomass increment but have a much weaker influence compared to the other two controlling factors. These results provide baseline information about the practical utility of spatial interpolationmethods for mapping forest biomass increments at regional scales.Yin Ren Shanshan Chen Xiaohua Wei Weimin Xi Yunjian Luo Xiaodong Song Shudi Zuo Yusheng Yang 2016Journal of Forestry Research2016,27,4:5
18Effects of atomization parameters of dust removal nozzles on the de-dusting results for different dust sources显示文摘In order to obtain appropriate spray pressure and enhance the spraying and dust removal efficiency, various factors including the dust characteristics, nozzle spraying angle, effective spraying range, water consumption and droplet size are taken into account. The dust characteristics from different mines and atomization parameters of different pressure nozzles were measured. It was found that the internal pressure of coal cutters and roadheaders should be kept at 2 MPa, which could ensure large droplet size, large spraying angle and low water consumption and hence realizing a large-area covering and capture for large particle dusts. However, the external spray pressure should be kept at 4 MPa for smaller droplet size and longer effective spraying range, leading to effective dust removal in the operator zone. The spray pressure of support moving, drawing opening, and stage loader on a fully mechanized caving face and stage loader on a fully mechanized driving face should be kept at 8 MPa, under which the nozzles have long effective spraying range, high water flow and small droplet size for the rapid capture of instantaneous, high-concentration and small size dust groups. From the applications on the caving and driving faces in the coal mines, it is indicated that the optimization of spray pressure in different spraying positions could effectively enhance dust removal efficiency. Selecting appropriate nozzles according to the dust characteristics at different positions is also favorable for dust removal efficiency. With the selected nozzles under optimal pressures, the removal rates of both total dust and respirable dust could reach over70%, showing a significant de-dusting effect.Cheng Weimin Ma Youying Yang Junlei Sun Biao 2016International Journal of Mining Science and Technology2016,26,6:4
19Stability analysis and optimization of excavation method of double-arch tunnel with an extra-large span based on numerical investigation显示文摘The Xiamen Haicang double-arch tunnel has a maximum span of 45.73 m and a minimum burial depth of 5.8 m.A larger deformation or collapse of the tunnel is readily encountered during tunnel excavation.It is therefore necessary to select a construction approach that is suitable for double-arch tunnel projects with an extra-large span.In this study,three construction methods for double-arch tunnels with extra-large spans were numerically simulated.Subsequently,the deformation behavior and stress characteristics of the surrounding rock were obtained and compared.The results showed that the double-side-drift method with temporary vertical support achieves better adaptability in the construction of such tunnels,which can be observed from both the numerical results and in situ monitoring data.In addition,the improved temporary support plays a critical role in controlling the surrounding rock deformation.In addition,the disturbance resulting from the excavation of adjacent drifts was obvious,particularly the disturbance of the surrounding rock caused by the excavation of the middle drift.The present findings can serve as the initial guidelines for the construction of ultra-shallowly buried double-arch tunnels with extra-large spans.Yiguo XUE Huimin GONG Fanmeng KONG Weimin YANG Daohong QIU Binghua ZHOU 2021Frontiers of Structural and Civil Engineering2021,15,1:4
20Heat transfer enhancement in a tube fitted with helical blade rotors with grooves显示文摘Zhen Zhang Weimin Yang Changfeng Guan Yumei Ding Hua Yan 2013Experimental Thermal and Fluid Science2013,,:4
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