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Search Results: 1 - 10 of 49168 matches for " XI Shi-Bo "
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Effect of elevated CO2 concentration and increased temperature on physiology and production of crops
大气[CO2]和温度升高对农作物生理及生产的影响

FANG Shi-Bo,SHEN Bin,TAN Kai-Yan,GAO Xi-Ning,
房世波
,沈斌,谭凯炎,高西宁

中国生态农业学报 , 2010,
Abstract: 全球大气CO2]和气温升高是全球气候变化对农作物产量影响最为重要的两个因子。本文着重介绍了CO2]和温度升高对农作物光合作用、呼吸作用、蒸腾作用、产量、品质等方面影响的研究进展。研究表明随着CO2]升高, 作物光合速率及蒸腾速率有上升趋势, 呼吸作用和气孔导度下降, 产量有所提高, 品质将会降低, 但研究仍有不确定性。随着CO2]变化, 不同光合途径(C3、C4)作物的响应不一致且存在短期和长期效应。普遍认为大气温度升高抑制作物光合作用, 作物产量下降。现有的研究多采用模型或模拟试验的方法研究气候变化对作物产量的影响, 但研究发现模型研究结果与模拟试验研究结果有差异, 不同学者对产量的评估结果也不一致。最新研究认为温度对作物产量影响成非线性, 当温度高于关键温度后产量会迅速下降。现阶段大部分模拟试验均在气室中研究, 与野外实际情况差异较大, 结论仍需进一步验证。目前尚缺乏对作物模型结果的实验验证。
Soft X-Ray Magneto-optical Faraday Effect around Ni M2,3 Edges
CHEN Kai,CUI Ming-Qi,YAN Fen,ZHAO Jia,SUN Li-Juan,ZHENG Lei,MA Chen-Yan,XI Shi-Bo,ZHAO Yi-Dong,

中国物理快报 , 2008,
Abstract: We present magneto-optical (MO) Faraday spectra measured around the M2,3 edges (60--70eV) of Ni films at the Beijing Synchrotron Radiation Facility (BSRF). A polarization analysis of the final state of the transmitted radiation from the Ni film is employed to determine the Faraday rotation at the edges. The MO effect becomes resonantly enhanced at the M2,3 edges, andaccordingly large values for the rotation angle β of 1.85±0.19°for this ferromagnetic Ni film with thickness of 31nm are measured. Without the magnetic field, the azimuthal angles do not shift; with parallel and antiparallel magnetic field the rotation angles shift in the opposite way and they are symmetrical. The uncertainty of Faraday rotation angles mainly comes from the data fitting and the state change of the beamline when the angles aremeasured.
Measurement of the polarization for soft x-ray magnetic circular dichroism at the BSRF beamline 4B7B
Guo Zhi-Ying,Xi Shi-Bo,Zhu Jing-Tao,Zhao YI-Dong,Zheng Lei,Hong Cai-Hao,Tang Kun,Yang Dong-Liang,Cui Ming-Qi
Physics , 2012,
Abstract: Three ultra-short-period W/B4C multilayers (1.244nm, 1.235nm and 1.034nm) have been fabricated and used for polarization measurement at the 4B7B Beamline of Beijing Synchrotron Radiation Facility (BSRF). By rotating analyzer ellipsometry method, the linear polarization degree of light emerging from this beamline has been measured and the circular polarization evaluated for 700eV-860eV. The first soft x-ray magnetic circular dichroism measurements are carried out at BSRF by positioning the beamline aperture out of the plane of the electron storage ring.
VARIATION IN SPECTRAL CHARACTERISTICS OF MOSS SOIL CRUST
苔藓结皮光谱的变异性研究

FANG Shi-Bo,
房世波

红外与毫米波学报 , 2010,
Abstract: 通过测定干、湿苔藓结皮光谱和不同季节的苔藓结皮光谱,研究了其水分变异性和季节变异性.研究得出,湿苔藓结皮光谱曲线与维管植物的光谱曲线相似,即苔藓在生命活动期的光谱曲线具有高等植物光谱曲线特征,干苔藓结皮光谱曲线特征与裸地土壤的光谱曲线相似;苔藓结皮光谱在苔藓营养发育期(7月)与生殖发育期(10月)存在较大差异,即苔藓结皮光谱也如维管植物一样存在季节变异.研究分析认为,苔藓结皮光谱与其所处环境的土壤水分有关,且苔藓结皮光谱象其他高等植物一样具有季节性变异,所以仅通过分析某一状态下的生物结皮的光谱与其他地物光谱的异同,构建的遥感解译方法很难具有普适性.由于湿苔藓结皮光谱与维管植物相似,苔藓结皮可能造成其盖度分布较大区域的植物指数的不稳定性和该区域植被生产力的过高估计.
Rolling Frictional Behavior of Nylon Composite Filled with Zinc Oxide Whisker
氧化锌晶须填充尼龙复合材料的滚动摩擦性能

WANG Shi-bo,GE Shi-rong,
王世博
,葛世荣

摩擦学学报 , 2007,
Abstract: 采用热压成型法制备氧化锌晶须(ZnOw)填充PA1010复合材料,在牵引滚动摩擦磨损试验机上研究复合材料的滚动牵引摩擦磨损性能,采用光学显微镜和扫描电子显微镜观察分析磨损表面及其转移膜形貌.结果表明:复合材料的牵引力系数、蠕滑比和磨损量随牵引负荷增加而升高;在同一牵引负荷条件下,蠕滑比和磨损量随ZnOw含量增加先降低而后增加,当ZnOw含量为10%和15%时,复合材料的蠕滑比和磨损量较低;尼龙基体的主要磨损机理为严重的塑性流动和基体溃裂,并伴有轻微粘着;当ZnOw含量为10%和15%时,犁沟是复合材料的主要磨损机制,同时在偶件表面形成了结构致密的转移膜;填充20%ZnOw的复合材料的磨损表面出现表层脱落,同时在偶件表面形成层状转移膜.
Spatial Variations of Heavy Metals in the Soils of Vegetable-Growing Land along Urban-Rural Gradient of Nanjing, China
Shi-Bo Fang,Hao Hu,Wan-Chun Sun,Jian-Jun Pan
International Journal of Environmental Research and Public Health , 2011, DOI: 10.3390/ijerph8061805
Abstract: China has experienced rapid urbanization in recent years. The acceleration of urbanization has created wealth and opportunity as well as intensified ecological and environmental problems, especially soil pollution. Our study concentrated on the variation of heavy metal content due to urbanization in the vegetable-growing soil. Laws and other causes of the spatial-temporal variation in heavy metal content of vegetable-growing soils were analyzed for the period of urbanization in Nanjing (the capital of Jiangsu province in China). The levels of Cu, Zn, Pb, Cd and Hg in samples of vegetable-growing soil were detected. The transverse, vertical spatio-temporal variation of heavy metals in soil was analyzed on the base of field investigations and laboratory analysis. The results show that: (1) in soil used for vegetable production, the levels of heavy metals decreased gradually from urban to rural areas; the levels of the main heavy metals in urban areas are significantly higher than suburban and rural areas; (2) the means of the levels of heavy metals, calculated by subtracting the sublayer (15–30 cm) from the toplayer (0–15 cm), are all above zero and large in absolute value in urban areas, but in suburban and rural areas, the means are all above or below zero and small in absolute value. The causes of spatial and temporal variation were analyzed as follows: one cause was associated with mellowness of the soil and the length of time the soil had been used for vegetable production; the other cause was associated with population density and industrial intensity decreasing along the urban to rural gradient ( i.e., urbanization levels can explain the distribution of heavy metals in soil to some extent). Land uses should be planned on the basis of heavy metal pollution in soil, especially in urban and suburban regions. Heavily polluted soils have to be expected from food production. Further investigation should be done to determine whether and what kind of agricultural production could be established near urban centers.
Statistical fluctuations in a saturation laser model with correlated noises
Chen Shi-Bo,Mei Dong-Cheng,
陈世波
,梅冬成

中国物理 B , 2006,
Abstract: We study the effects of correlations between quantum and pump noises on fluctuations of the laser intensity in a saturation laser model. An approximative Fokker--Planck equation and analytic expressions of the steady-state probability distribution function (SPD) of the laser system are derived. Based on the SPD, the normalized mean, the normalized variance, and the normalized skewness of the steady-state laser intensity are calculated numerically. The results indicate that (i) the correlation strength \lambda of correlated noises always enhances the fluctuation of laser intensity; (ii) the correlation time \tau of correlated noises strengthens the fluctuation of laser intensity for the below-threshold case but \tau weakens it for the above-threshold case.
Application of pressure wire in carotid artery stenting
WANG Shi-bo,LI Xu-dong,JIA Qiang,HAN Jing
Chinese Journal of Contemporary Neurology and Neurosurgery , 2013, DOI: 10.3969/j.issn.1672-6731.2013.03.010
Abstract: Background Nowad ays, critical carotid stenosis lacks appropriate treatment standards, and carotid artery stenting (CAS) needs more direct guidance. This study aims to investigate the possibility of applying pressure wire in CAS, and the guidance of pressure gradients in choosing indications of CAS. Methods From May 2012 to October 2012, 32 consecutive cases with carotid stenosis undergoing CAS were enrolled. Preoperative and postoperative carotid ultrasound and CT perfusion imaging were performed, and intraoperative measurements of endovascular pressure gradients before and after stent implantation were recorded to evaluate intracranial circulation compensation. Results Preopera tive carotid ultrasound showed the rate of stenosis in 32 cases was≥70% or nearly total occlusion. Doppler measurement of peak systolic velocity (PSV) of the stenosed vessel ranged 184-718 cm/s. Digital subtraction angiography (DSA) examination showed the stenosis rates were 50%-70% in 7 cases, 70%-90% in 16 and > 90% in 9. The coincidence rate of carotid ultrasound and DSA was 84.38% (27/32), and the acquisition rate of intraoperative carotid pressure gradients was 100%. Pressure gradients before stent implantation were 10-92 mm Hg, with an average of (41.45 ± 25.50) mm Hg, and pressure gradients after stent implantation were 0-15 mm Hg, with an average of (3.44 ± 3.47) mm Hg. DSA revealed 4 cases with good intracranial circulation compensation and 28 cases with poor intracranial circulation compensation. Conclusion Pressure wire can be safely and effectively used in CAS to acquire pressure gradients between the two ends of stenosis segment. For carotid artery stenosis patients lacking of intracranial circulation compensation, pressure gradients become higher as stenosis rate increases within a certain range. Therefore, CAS for stenosis with lower pressure gradients should be reconsidered.
Strategies in the treatment for intracranial venous sinus thrombosis
FAN Yi-mu,LI Xu-dong,WANG Shi-bo,JIA Qiang
Chinese Journal of Contemporary Neurology and Neurosurgery , 2013, DOI: 10.3969/j.issn.1672-6731.2013.03.013
Abstract: Background Cerebral venous sinus thrombosis (CVST) is a special type of cerebrovascular disease with high morbidity and mortality which often has an unpredictable outcome. It is usually misdiagnosed because of different causes and variable clinical manifestations. How to improve the diagnosis and therapy of CVST is always the hotspot in clinic. This article aims to investigate the effective and safe strategies in the treatment for CVST. Methods Clinical data of 52 patients diagnosed with CVST were retrospectively analyzed. These patients were subdivided into mild type and severe type according to the features of symptoms, signs, lumbar puncture pressure and imaging. The patients with mild type were treated with systemic anticoagulant therapy combined with intravenous thrombolysis [continuous intravenous infusion of heparin (12.50-25 ) × 103 U/d for 7-10 d followed by a continuous infusion of urokinase (0.50-0.75) ×106 U/d for 5-7d]. The patients with severe type were treated with endovascular thrombolysis [injection of urokinase (0.50-1 ) × 106 U, 0.10 × 106 U/min via carotid or vertebral artery; or intravenous infusion of urokinase 1 ×106 U/d and heparin 25 ×103 U/d for 5-7 d], and superior sagittal sinus cut-open/ intrasinus thrombolysis separately. All the patients took oral warfarin for 6-12 months, and follow-up was performed after operation by the method of magnetic resonance venography (MRV). Results Among the 27 cases of mild type receiving systemic anticoagulant agents and intravenous thrombolysis, 14 were cured; 9 were improved; 4 were ineffective. Among the 22 cases of severe type receiving systemic anticoagulant drugs and endovascular thrombolysis, 18 were cured; 3 were improved; 1 was dead. The left 3 cases with gravis type received superior sagittal sinus cut-open/intrasinus thrombolysis and were cured. The period of follow-up was between 6 months and 60 months (the median time was 36 months), and no recurrence happened. Conclusion It was probable to subdivide CVST into mild type and severe type according to the features of symptoms, signs, lumbar puncture pressure and imaging. Different therapeutic strategies were proved to be safe and effective in the treatment of different types.
Soft X-ray magmeto-optical Faraday rotation measurements with the multilayer polarizer
基于多层膜偏振元件的软X射线磁光Faraday偏转测量

Yan Fen,Cui Ming-Qi,Chen Kai,Sun Li-Juan,Xi Shi-Bo,Zhou Ke-Jin,Zheng Lei,Zhao Yi-Dong,Wang Zhan-Shan,Zhu Jing-Tao,Zhang Zhong,Zhao Jia,
鄢 芬
,崔明启,陈 凯,孙立娟,席识博,周克瑾,郑 雷,赵屹东,王占山,朱京涛,张 众,赵 佳

物理学报 , 2008,
Abstract: 在北京同步辐射装置(BSRF)的3W1B软X射线光束线上利用自行研制的同步辐射软X射线综合偏振测量装置对Ni的M2,3边附近(60—70 eV)进行了软X射线磁光(magneto-optical)法拉第效应(Faraday effect)的偏转测量,实验装置主要由起偏器,检偏器,样品架,圆形钕铁硼永磁铁和MCP探测器组成,偏振元件(起偏元件和检偏元件)均采用反射式非周期性Mo/Si宽带多层膜.实验采用反射起偏和反射检偏的模式,得到一系列能量范围在60—70 eV间的法拉第偏转角结果,
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