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Search Results: 1 - 10 of 144867 matches for " LI Guang-Qi "
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Different responses of radial growth to climate warming in Pinus koraiensis and Picea jezoensis var.komarovii at their upper elevational limits in Changbai Mountain,China
长白山红松和鱼鳞云杉在分布上限的径向生长对气候变暖的不同响应

LI Guang-Qi,BAI Fan,SANG Wei-Guo,
李广起
,白帆,桑卫国

植物生态学报 , 2011,
Abstract: Aims Temperature is generally considered the limiting factor for tree growth at species’ upper elevational limits. Our objectives were to determine the upper elevational limit response of radial growth in Pinus koraiensis and Picea jezoensis var. komarovii to climate warming in Changbai Mountain Nature Reserve of China and to elucidate temperature sensitivity of radial growth. Methods We selected typical trees at each species’ upper limit for increment coring and established ring-width chronologies for both species. We compared the general trend of the chronologies with temperatures during 1958–2006. To determine species’ response to rising temperature, we analyzed the relationship between chronology and important meteorological factors (temperature, precipitation, growing season length, effective accumulative temperature, etc.) using correlation, response function, moving correlation and pointing year analyses. Important findings As temperature rose, ring widths in Pinus koraiensis exhibited the same increasing trend as temperature, while ring widths in Picea jezoensis var. komarovii exhibited decreasing sensitivity to temperature. The increase of temperature and precipitation in the growing season mutually enhance Pinus koraiensis growth. Prolongation of the growing season and rising temperature during the growing season also can accelerate the growth of Pinus koraiensis. For Picea jezoensis var. komarovii, water stress caused by increasing temperature is the main reason for its relationship between ring width and temperature. Correlations between Picea jezoensis var. komarovii ring width and almost all temperature indices are significantly negative. As temperature rose, correlations between ring width and precipitation, especially spring precipitation, changed from negative to positive. High temperature in each month and inadequate precipitation in the middle and late growing season are the important meteorology conditions for narrow rings. Also, the insignificant extension of the growing season may relate to reduced temperature sensitivity in tree ring growth.
New channel for producing biexcition in polymers
聚合物中产生双激子的新通道

Zhang Xi-Juan,Li Guang-Qi,Sun Xin,
张锡娟
,李广起,孙鑫

物理学报 , 2002,
Abstract: How to excite the biexctions in a polymer is an essential subject, since the biexciton possesses an effect of photo\|induced polarization reversion. This paper proposes a new channel to produce the biexciton through two\|electron excitation. The relaxation processes of both lattice distortion and electronic states are simulated by studying its dynamics, and the relaxation time of biexciton formation and polarization reversion is determined.
Seasonal dynamics in leaf area index in three typical temperate montane forests of China:a comparison of multi-observation methods
3类典型温带山地森林的叶面积指数的季节动态:多种监测方法比较

SU Hong-Xin,BAI Fan,LI Guang-Qi,
苏宏新
,白帆,李广起

植物生态学报 , 2012,
Abstract: Aims Leaf area index (LAI) is one of the most frequently used parameters for analysis of canopy structure and forest productivity. It can be determined by direct or indirect methods. Sources of errors in indirect LAI measurements with optical instruments include non-photosynthetic components, element clumping, and a topography effect. Our objective was to find an appropriate method for evaluating LAI and its seasonal dynamics in typical temperate montane forest. Methods We examined the applicability of three indirect methods (LAI-2000 plant canopy analyzer, CI-110 plant canopy analyzer and digital hemispherical photograph (DHP)) and one direct method (litterfall) to determine the seasonal dynamics of LAI in three typical temperate forests in Dongling Mountain of Beijing. The forests included a secondary deciduous broad-leaved forest dominated by Quercus mongolica and two plantations (Larix gmelinii var. principis-rupprechtii and Pinus tabuliformis). These represent deciduous broad-leaved forest, deciduous needle-leaved forest and evergreen needle-leaved forest, respectively. The optically-based effective leaf area index (LAIe) values were corrected to eliminate wood elements and clumping effects and then compared with the direct measurement of LAI based on litter collection. Important findings For all the three forests, the LAI seasonal dynamic shows a uni-modal pattern with a peak in July. Optically-based LAIe underestimated the amplitude of the seasonal dynamics. Wood element elimination can strengthen the seasonal sensitivity of LAI, especially in the seasonally distinct deciduous forest. The order of LAIe measured by the three optically-based methods in three stands is LAI-2000 plant canopy analyzer > DHP > CI-110 plant canopy analyzer. There was good correspondence with the direct measurement LAI for the corrected LAI of LAI-2000 plant canopy analyzer and DHP. The correction method based on gap-size distribution was appropriate for the LAI-2000 plant canopy analyzer and the method based on both gap fraction and gap-size distribution for DHP. Considering economics and practical convenience, we recommend DHP for LAI evaluation in these temperate montane forests.
Functional Annotation of Rheumatoid Arthritis and Osteoarthritis Associated Genes by Integrative Genome-Wide Gene Expression Profiling Analysis
Zhan-Chun Li, Jie Xiao, Jin-Liang Peng, Jian-Wei Chen, Tao Ma, Guang-Qi Cheng, Yu-Qi Dong, Wei-li Wang, Zu-De Liu
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0085784
Abstract: Background Rheumatoid arthritis (RA) and osteoarthritis (OA) are two major types of joint diseases that share multiple common symptoms. However, their pathological mechanism remains largely unknown. The aim of our study is to identify RA and OA related-genes and gain an insight into the underlying genetic basis of these diseases. Methods We collected 11 whole genome-wide expression profiling datasets from RA and OA cohorts and performed a meta-analysis to comprehensively investigate their expression signatures. This method can avoid some pitfalls of single dataset analyses. Results and Conclusion We found that several biological pathways (i.e., the immunity, inflammation and apoptosis related pathways) are commonly involved in the development of both RA and OA. Whereas several other pathways (i.e., vasopressin-related pathway, regulation of autophagy, endocytosis, calcium transport and endoplasmic reticulum stress related pathways) present significant difference between RA and OA. This study provides novel insights into the molecular mechanisms underlying this disease, thereby aiding the diagnosis and treatment of the disease.
License Plate Location Based on Texture Characteristic of Image
基于图像纹理特征提取的车牌定位算法

LIU Guang-qi,LIU Guang-qi,LIU Guang-qi,
刘广起
,郑晓势,张晓波

中国图象图形学报 , 2005,
Abstract: It is the important part of license plate location in license plate recognition technology.In this paper,orients an algorithm of license plate location on the basis of texture characteristic of license plate binary image combined with line scanning.Studies have shown that the algorithm of license plate location can get better result,and the algorithm has better interference immunity.
A comparison of photosynthetic characteristics between an invasive plant Spartina alterniflora and an indigenous plant Phragmites australis
芦苇与入侵植物互花米草的光合特性比较

ZHAO Guang-Qi,
赵广琦

生态学报 , 2005,
Abstract: As a consequence of rapid globalization, greatly increased emphasis is being placed on research into the ecology of invasive plants. Since Spartina alterniflora was introduced into Chongming Dongtan in 1995, it has gradually occupied a large area of the Phragmites australis zone, and has became a threat to the intertidal vegetation.. In this study, the photosynthetic characteristics of an invasive plant, Spartina alterniflora, and an indigenous plant, Phragmites australis, were measured during the growing s...
PHASE IN Fe-C, Fe-C-Sb ALLOY SYSTEMS OBTAINED BY SPLAT QUENCHING
用液态急冷法在Fe-C,Fe-C—Sb系中获得ε相

WU DE-HAI,LIN ZHI-WEI,LI CHUN-LI,LIANG GUANG-QI,LU JIN-WEN,CHEN XI-CHEN,YI SUN-SHENG,WANG ZU-LUN,
吴德海
,林子为,李春立,梁光启,卢锦文,陈熙琛,易孙圣,王祖崙

物理学报 , 1981,
Abstract: 本工作用液态急冷法在Fe-C,Fe-C-Sb系合金中获得h.c.p.结构的介稳相ε。ε相是一个固溶体,其晶格常数随着含碳量和含锑量的增加而增大,但c/α值则近于恒量。Fe-C-Sb合金中的8相具有一定的热稳定性,差热分析指出,它在125℃以下不分解,而且Si和Sb的加入提高了ε相的稳定性。ε相的晶粒细小,为10-1微米级,晶界粗宽。本工作对Ruhl和Cohen等由Fe-C-Si系合金获得ε相的工作进行了验证。用扫描电子显微镜及透射电子显微镜对ε相的形貌进行了观察。
PREPARATION OF MANGANESE DIOXIDE MODIFIED GLASSY CARBON ELECTRODE BY A NOVEL FILM PLATING/CYCLIC VOLTAMMETRY METHOD FOR H(2)0(2) DETECTION
WEN-ZHI,LE; YOU-QIN,LIU; GUANG-QI,HU;
Journal of the Chilean Chemical Society , 2009, DOI: 10.4067/S0717-97072009000400009
Abstract: manganese dioxide modified glassy carbon electrode (mn02/gc) was prepared by a novel film plating/cyclic voltammetry method for the determination of h202. a manganese film was first cathodically deposited on the surface of glassy carbon electrode from mncl2 solution at the potential of-1.4 v versus ag/ agcl (satd. kc1), and then a well defined manganese dioxide was deposited on the surface of glassy carbon electrode by cyclic voltammetry at potential range -0.6 ~ 0.6 v, scan rate 100 mv s-1 in 0.1 mol l71 naoh solution. the resulted modified electrode was characterized by cyclic voltammetry and scanning electron microscopy (sem), which showed excellent electrocatalytic activity for the oxidation of h202. the chronoamperometric detection of h202 was carried out at 0.6 v in phosphate buffer solution ph 7.38 containing 0.1 mol l71 kc1 and the linear relationship of response current on h202 concentration was obtained in the range from 4. ixl0~10 to lxl0~-mol l-1 with a minimum detectable concentration of 3xl0~10 mol l71 [s/n (signal noise ratio) = 3]. the response time of the electrode to achieve 95% of the steady-state current was < 2 s. no measurable reduction in analytical performance of the modified electrode was found by storing the electrode in ambient conditions for 30 days. this modified electrode has many advantages such as simple preparation procedure, remarkable catalytic activity, good reproducibility and long term stability of signal response during hydrogen peroxide oxidation. the deposition of manganese dioxide on the surface of gc appears to be a highly efficient method for the development of a new class of sensitive, stable and reproducible hydrogen peroxide electrochemical sensor.
A four-armed Schiff base: 6,6′,6′′,6′′′-tetramethoxy-2,2′,2′′,2′′′-[methanetetrayltetrakis(methylenenitrilomethylidyne)]tetraphenol
Guang-Qi Jiang,Jie Cai,Yun-Qian Zhang,Qian-Jun Zhang
Acta Crystallographica Section E , 2008, DOI: 10.1107/s1600536808020618
Abstract: In the structure of the title compound, C37H40N4O8, pentaerythrityltetramine is bonded to four o-vanillin molecules, forming a four-armed Schiff base molecule. These molecules are connected by intermolecular C—H...O hydrogen bonds. Intramolecular C—H...N and O—H...N hydrogen bonds are also present.
PREPARATION OF MANGANESE DIOXIDE MODIFIED GLASSY CARBON ELECTRODE BY A NOVEL FILM PLATING/CYCLIC VOLTAMMETRY METHOD FOR H(2)0(2) DETECTION
LE WEN-ZHI,LIU YOU-QIN,HU GUANG-QI
Journal of the Chilean Chemical Society , 2009,
Abstract: Manganese dioxide modified glassy carbon electrode (Mn0(2)/GC) was prepared by a novel film plating/cyclic voltammetry method for the determination of H(2)0(2). A manganese film was first cathodically deposited on the surface of glassy carbon electrode from MnCl2 solution at the potential of-1.4 V versus Ag/ AgCl (satd. KC1), and then a well defined manganese dioxide was deposited on the surface of glassy carbon electrode by cyclic voltammetry at potential range -0.6 ~ 0.6 V, scan rate 100 mV s-1 in 0.1 mol L71 NaOH solution. The resulted modified electrode was characterized by cyclic voltammetry and scanning electron microscopy (SEM), which showed excellent electrocatalytic activity for the oxidation of H(2)0(2). The chronoamperometric detection of H(2)0(2) was carried out at 0.6 V in phosphate buffer solution pH 7.38 containing 0.1 mol L71 KC1 and the linear relationship of response current on H(2)0(2) concentration was obtained in the range from 4. Ixl0~10 to lxl0~-mol L-1 with a minimum detectable concentration of 3xl0~10 mol L71 [S/N (signal noise ratio) = 3]. The response time of the electrode to achieve 95% of the steady-state current was < 2 s. No measurable reduction in analytical performance of the modified electrode was found by storing the electrode in ambient conditions for 30 days. This modified electrode has many advantages such as simple preparation procedure, remarkable catalytic activity, good reproducibility and long term stability of signal response during hydrogen peroxide oxidation. The deposition of manganese dioxide on the surface of GC appears to be a highly efficient method for the development of a new class of sensitive, stable and reproducible hydrogen peroxide electrochemical sensor.
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