检索结果-南通市图书馆

Biomedical and Environmental Sciences 2012年第4期25卷 392-398页

作者： ma ka Ying LIANG Yin Tong CHEN Jing Nan JIANG Yue KWAN Kin Ming PENG Cheng JIAO Rui ZUO Yuan Yuan HUANG Yu CHEN Zhen Yu Food & Nutritional Sciences Programme School of Life Sciences The Chinese University of Hong Kong Shatin NT Hong Kong China Department of Biology and Kwong Living Trust Food Safety & Analysis Laboratory Hong Kong Baptist University Kowloon Tong Hong Kong China School of Biomedical Sciences The Chinese University of Hong Kong Shatin NT Hong Kong China

Objective To investigate the effect of dietary calcium on plasma lipoprotein profile in castrated and ovariectomized hamsters. Methods male, castrated, female and ovariectomized hamsters （n=36 each group） were randomly divided into three sub-groups （n=12） and fed one of the three diets containing O, 2, and B g calcium per kg diet for a period of six weeks. Changes in plasma lipoprotein profile were monitored at the end of week O, 3 and 6. Results Plasma total cholesterol （TC）, non-high density lipoprotein cholesterol （non-HDL-C）, triacylglycerols （TG） and TC/HDL-C were decreased only in intact female and ovariectomized hamsters. In contrast, three levels of dietary calcium had no effect on lipoprotein profiles in both intact male and castrated hamsters. Conclusion Beneficial modification of lipoprotein profile by dietary calcium was gender-dependent at least in hamsters.

关键词： Calcium Cholesterol Triacylglycerols Fecal sterols

Effect of Fertilization on the Dynamics and Activity of Iron-Reducing Bacterial Populations in a West African Rice Paddy Soil Planted with Two Rice Varieties: Case Study of Kou Valley in Burkina Faso

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Protection 2016年第8期7卷 1119-1131页

作者： Cè cile Harmonie Otoidobiga Adama Sawadogo Yapi Sinarè Ibrahima ouè draogo Prosper Zombrè Susumu Asakawa Alfred S. traore Dayè ri Dianou Research Center for Biological Alimentary and Nutritional Sciences Research and Training Unit Life and Earth Sciences University of Ouagadougou Ouagadougou Burkina Faso Institute of Environment and Agricultural Research Bobo Dioulasso Burkina Faso Laboratory of Soil-materials and Environment Research and Training Unit Life and Earth Sciences University of Ouagadougou Ouagadougou Burkina Faso Soil Biology and Chemistry Graduate School of Bio-Agricultural Sciences Nagoya University Chikusa Nagoya Japan National Center for Sciences and Technology Research Ouagadougou Burkina Faso

Iron toxicity is a major stress to rice caused by a high concentration of reduced iron, in the soil in many lowlands worldwide. To reduce iron toxicity in the West African lowlands, an investigation was performed at the site of the University of ouagadougou, in pots containing an iron toxic soil from the Kou Valley (West of Burkina Faso). The experiment objective was to study the effect of mineral fertilizer on Iron Reducing Bacteria (IRB) dynamics and activity during rice cultivation, iron accumulation in rice plant and rice biomass yield under iron toxicity conditions. BouAKE-189 and ROK-5 rice varieties, sensitive and tolerant to iron toxicity, respectively, were used for the experiment. The pots were amended with chemical fertilizers (NPK + Urea and NPK + Urea + Ca + Mg + Zn complex). Control pots without fertilization were prepared similarly. The kinetics of IRB and ferrous iron content in soil near rice roots were monitored throughout the cultural cycle using MPN and colorimetric methods, respectively. The total iron content was evaluated in rice plant using spectrometric method. Data obtained were analyzed in relation to fertilization mode, rice growth stage and rice yield using the student’s t-test and XLSTAT 2014 statistical software. The experiment revealed that NPK + Urea and NPK + Urea + Ca + Mg + Zn fertilization, decreased significantly (p ouAKE-189 rice varieties. In most pots, highest IRB densities and ferrous iron content in soil were recorded from rice tillering and flowering to maturity stages, indicating that rice plants promoted microbial processes and iron reduction in soil. From the study, the NPK + Urea amendment decreased significantly ferrous iron content (p ouAKE-189 and ROK-5 rice varieties roots relatively to control pots. However, NPK + Urea + Ca + Zn + Mg amendment increased significantly ferrous iron content (p < 0.0001) in the soil near roots, Fe accumulation in pla

关键词： Iron-Reducing Bacteria Rice Iron Toxicity Fertilization

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

生物逆问题中测量信息的熵描述

四川大学学报（工程科学版） 2008年第5期40卷 142-145页

作者：李静黄卡玛四川大学电子信息学院四川成都610064

针对生物逆问题中参数识辨前的重要问题——测量点位置的选取,应用贝叶斯理论,采用待识辨参数的后验概率来定义参数样本出现的概率,将信息熵引入到测量信息的描述中,利用信息熵构造出评价因子,通过评价因子表示出不同位置测量点的"贡献... 详细信息

针对生物逆问题中参数识辨前的重要问题——测量点位置的选取,应用贝叶斯理论,采用待识辨参数的后验概率来定义参数样本出现的概率,将信息熵引入到测量信息的描述中,利用信息熵构造出评价因子,通过评价因子表示出不同位置测量点的"贡献"大小。对单物种生态模型的计算结果表明:用信息熵表示的评价因子能够较好地反映重构误差的变化规律,有效地描述不同位置的测量点对参数识辨的贡献大小。

关键词：逆问题信息熵贝叶斯方法评价因子

磁聚焦电导率成像系统信号源与信号提取的实现

在线全文

学校读者我要写书评

暂无评论

四川大学学报（工程科学版） 2006年第2期38卷 155-158页

作者：傅林黄卡玛四川大学电子信息学院四川成都610064

为了提高信号源的稳定度和实现扫频检测,以提取更可靠、更丰富的有用信号,信号源用直接数字频率合成器设计,输出频率为1～20 MHz的扫频正弦波信号,通过具有很好聚焦特性的平面螺旋线圈接成调幅电路输出.同时平面螺旋线圈采用差分线圈结... 详细信息

为了提高信号源的稳定度和实现扫频检测,以提取更可靠、更丰富的有用信号,信号源用直接数字频率合成器设计,输出频率为1～20 MHz的扫频正弦波信号,通过具有很好聚焦特性的平面螺旋线圈接成调幅电路输出.同时平面螺旋线圈采用差分线圈结构以检测和提取信号,其输出送往由集成乘法器MC1595组成的鉴相电路,使鉴相器输出相位变化随着输入信号的频差变化,利用低通滤波器滤除扫频载波从而提取线圈有目标以及目标变化时的频差信号.获得了足够的可靠数据,提高了系统的稳定度,提高了成像系统的空间分辨率.有利于系统软件进行电导率反演和成像.

关键词：磁聚焦电导率成像信号源平面螺旋聚焦线圈乘法器信号提取

温度对PIN二极管限幅器功率响应特性的影响

在线全文

学校读者我要写书评

暂无评论

强激光与粒子束 2008年第4期20卷 645-648页

作者：王波黄卡玛四川大学电子信息学院成都610064

通过求解PIN二极管基区双极载流子扩散方程得到了限幅器Pspice等效电路模型,根据PIN二极管物理参数与温度的关系,数值计算得到了PIN二极管限幅器在多个温度点的功率响应特性,发现温度的升高会使限幅器内部损耗增加,加剧限幅器内部热损... 详细信息

通过求解PIN二极管基区双极载流子扩散方程得到了限幅器Pspice等效电路模型,根据PIN二极管物理参数与温度的关系,数值计算得到了PIN二极管限幅器在多个温度点的功率响应特性,发现温度的升高会使限幅器内部损耗增加,加剧限幅器内部热损伤。并利用恒温控制系统进行了实验验证,实验结果与数值计算结果相符合。实验还发现高温热冲击可能使限幅器限幅能力大幅下降,可能成为通信系统的重大安全隐患。

关键词： PIN二极管微波限幅器功率响应特性温度

大功率PIN二极管限幅器对电磁脉冲后沿响应的分析

在线全文

学校读者我要写书评

暂无评论

强激光与粒子束 2008年第7期20卷 1177-1181页

作者：王波黄卡玛四川大学电子信息学院成都610064

利用PSpice电路模型数值计算了阶跃电磁脉冲后沿作用下大功率PIN二极管限幅器的瞬态响应。发现大功率限幅器在阶跃脉冲后沿作用下会输出反向脉冲,其幅度可能与限幅器尖峰泄漏的幅值相当甚至更大,这可能是一种新的影响限幅器性能的安全... 详细信息

利用PSpice电路模型数值计算了阶跃电磁脉冲后沿作用下大功率PIN二极管限幅器的瞬态响应。发现大功率限幅器在阶跃脉冲后沿作用下会输出反向脉冲,其幅度可能与限幅器尖峰泄漏的幅值相当甚至更大,这可能是一种新的影响限幅器性能的安全隐患。分析发现:反向脉冲幅度在一定范围内随激励脉冲持续时间的增加、幅度的加大、后沿时间的变短而变大;随射频扼流电感值的增加而减小。

关键词：大功率PIN二极管限幅器 PSpice模型阶跃电磁脉冲脉冲后沿反向脉冲安全隐患

Study of the Chemical and Mineralogical Composition of Kindia Bauxite in the Republic of Guinea: The Case of the Saföfö Site

在线全文

学校读者我要写书评

暂无评论

Journal of materials Science and Chemical Engineering 2024年第10期12卷 62-71页

作者： Mouctar Camara ma.a.ouba Aboubacar Fofana Mohamed Dubréka Sylla Alpha madiou Diallo Aboubacar Diallo Aly Hawa Camara Sékou traore Department of Chemical Engineering Gamal Abdel Nasser University of Conakry Conakry Republic of Guinea Department of Physics University of NZerekore NZerekore Republic of Guinea Department of Chimie Gamal Abdel Nasser University of Conakry Conakry Republic of Guinea Institut Superieure dArchitecture and lUrbanisme (ISAU) Conakry Republic of Guinea National Laboratory of the Geology Department from Mines and of the Geology Conakry Republic of Guinea

The chemical and mineralogical composition of bauxite deposits is a key factor in the profitability of refining processes. The study of bauxites from the Saföfö site has assessed variations in chemical and mineralogical composition under various conditions, as well as the optimum conditions for their exploitation. The methodologies used in this study include experimental methods for determining moisture content, chemical composition, mineralogical composition, and specific density of bauxite. The results show significant variation in moisture content among the bauxite samples, with values ranging from 2.90% to 17.80%. The silica percentages in the samples range from 1.69% to 8.14%, while alumina percentages vary from 36.81% to 54.03%. After calcination, alumina oxide percentages range from 40% to 75%. After chemical activation, alumina oxides Al2O3 range from 40% to over 50%. Gibbsite is the most abundant mineral, accounting for about 60% - 70% of the total composition of the bauxite samples. Samples A to F have bulk densities varying between approximately 3.6 and 3.9. Sample B has the highest density, around 3.9, while sample C has the lowest, at around 3.5. Bauxite mining at the Saföfö site offers significant potential for the alumina industry, provided appropriate processing methods are selected to maximize quality and profitability while minimizing environmental impact.

关键词： Bauxite Chemical Composition Guinea Mineralogy and Saföfö

High-power,electrically-driven continuous-wave 1.55-μm Si-based multi-quantum well lasers with a wide operating temperature range grown on wafer-scale InP-on-Si(100)heterogeneous substrate

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Light(Science & Applications) 2024年第8期13卷 1512-1523页

作者： Jialiang Sun Jiajie Lin Min Zhou Jianjun Zhang Huiyun Liu Tiangui You Xin ou National Key Laboratory of materials for Integrated Circuits Shanghai Institute of Microsystem and Information TechnologyCASShanghai 200050China Center of materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences100049 BeijingChina College of Information Science and Engineering Jiaxing UniversityJiaxing 314001China Beijing National Laboratory for Condensed matter Physics Institute of PhysicsChinese Academy of Sciences100190 BeijingChina Department of Electronic and Electrical Engineering University College LondonLondon WC1E 7JEUK

A reliable,efficient and electrically-pumped Si-based laser is considered as the main challenge to achieve the integration of all key building blocks with silicon *** the impressive advances that have been made in developing 1.3-μm Si-based quantum dot(QD)lasers,extending the wavelength window to the widely used 1.55-μm telecommunication region remains *** this study,we develop a novel photonic integration method of epitaxial growth of III-V on a wafer-scale InP-on-Si(100)(InPOS)heterogeneous substrate fabricated by the ion-cutting technique to realize integrated lasers on Si *** ion-cutting plus epitaxial growth approach decouples the correlated root causes of many detrimental dislocations during heteroepitaxial growth,namely lattice and domain *** this approach,we achieved state-of-the-art performance of the electrically-pumped,continuouswave(CW)1.55-μm Si-based laser with a room-temperature threshold current density of 0.65 ka/cm^(-2),and output power exceeding 155mW per facet without facet coating in CW *** lasing at 120℃ and pulsed lasing at over 130℃ were *** generic approach is also applied to other material systems to provide better performance and more functionalities for photonics and microelectronics.

关键词： pumped power quantum

Cesarean Section Indications and Prognosis in Adolescents Girls at the Mother-Child Pool of the Teaching Hospital of Tengandogo (CHU-T) in Burkina Faso

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Obstetrics and Gynecology 2021年第12期11卷 1744-1751页

作者： kain Dantola Paul Zamané Hyacinthe Compaoré ousséni Adediran Sofiath Nancy Millogo/traore Françoise ouédraogo Ali Bonané/Thiéba Blandine Teaching Hospital of Tengandogo Ouagadougou Burkina Faso Yalgado ouedraogo Teaching Hospital Ouagadougou Burkina Faso

Objective: Conduct a study on cesarean sections in adolescent girls at the mother-child pool of the CHU-T in order to reduce maternal-fetal morbidity and mortality. Patients and Methods: This was a descriptive and cross-sectional study with a retrospective data collection method from January 1st, 2018 to December 31st, 2019. Results: The frequency of caesarean sections in our series was estimated at 59.9% in adolescent girls. 68.7% of adolescent girls were married, the average age was estimated at 18.3 ± 1 years, primiparous women were the most represented group with a rate of 88%. Adolescent girls were housewives in 73.5% of cases, with 37.4% of them living in rural areas. The main indications for cesarean section were: pre-rupture syndrome (22.9%), fetal distress (19.3%), pre-ecl

关键词： Cesarean Section Adolescent Girls Indications Prognosis

Optically stimulated luminescence dating of young glacial sediments from the eastern Qinghai-Tibetan Plateau

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Mountain Science 2016年第7期13卷 1174-1185页

作者： ZENG Lan-hua ou Xian-jiao LAI Zhong-ping ZHou Shang-zhe School of Geography and Tourism Jiaying University State Key Laboratory of Biogeology and Environmental Geology School of Earth Sciences China University of Geosciences School of Geographical Science South China Normal University

Poor bleaching is a significant problem for Optically Stimulated Luminescence(OSL) dating of glacial sediments. Five young glacial samples(including two modern analogues) from different depositional settings were collected beyond the Yingpu Glacier in the eastern Qinghai-Tibetan Plateau. De was determined using different OSL methods. The luminescence characteristics and dating results showed that the large aliquot quartz Blue Stimulated Luminescence(BSL) is more applicable than polymineral infrared stimulated luminescence(IRSL) method. Small aliquot quartz BSL results showed poor luminescence properties due to low luminescence sensitivity of quartz in this area. The dating results also indicated that glaciofluvial samples deposited close to ice margin(~40 m and ~700 m) and supraglacial debris dominated lateral moraine samples are relatively well-bleached, whereas samples from ground moraine and low terminal moraine were poorly bleached, probably due to containing subglacial and englacial debris. The residual doses of glaciofluvial and lateral moraine crest samples were below a few Gy and age overestimations were below a few hundred years. The ground moraine and low terminal moraine samples had residual doses as high as ~110 Gy, and ages were overestimated by ~15-17 ka.

关键词： Glacial sediments Optically stimulated luminescence Quartz Residual age Qinghai-Tibetan Plateau