检索结果-南通市图书馆

USING THE SKEW-SYMMETRIC ITERATIVE METHODS FOR SOlUTION OF AN INDEFINITE NONSYMMETRIC lINEAR SYSTEMS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2014年第3期32卷 266-271页

作者： B.l. Krukier l.a. Krukier Southern Federal University Computer Center Rostov-on-Don Russia

The concept of the field of value to localize the spectrum of the iteration matrices of the skew-symmetric iterative methods is further exploited. Obtained formulas are derived to relate the fields of values of the original matrix and the iteration matrix. This allows us to determine theoretically that indefinite nonsymmetric linear systems can be solved by this class of iterative methods.

关键词： Skew-symmetric iterative methods Indefinite nonsymmetric linear systems.

Use and application of CFC-11,CFC-12,CFC-113 and SF6 as environmental tracers of groundwater residence time:A review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Geoscience Frontiers 2019年第5期10卷 1643-1652页

作者： l.a. Chambers D.C. Gooddy A.M. Binley Department of Civil.a.d Environmental Engineering University of StrathclydeGlasgowG1 1XJUK lancaster Environment Centre Lancaster UniversityLancasterLA1 4YQUK British Geological Survey Maclean BuildingWallingfordOX10 8BBUK

Groundwater residence time is a fundamental property of groundwater to understand important hydrogeological issues,such as deriving sustainable abstraction volumes,or,the evolution of groundwater quality.The anthropogenic trace gases chlorofluorocarbons (CFC-11,CFC-12 and CFC-113) and sulphur hexafluoride (SF6) are ideal in this regard because they have been rel.a.ed globally at known rates and become dissolved in groundwater following Henry’s law,integrating over large spatial (global) and temporal (decades) scales.The CFCs and SF6 are able to date groundwater up to w100 years old with the caveat of certain simplifying assumptions.However,the inversion of environmental tracer concentrations (CFCs and SF6) to derive groundwater age rests on the accurate determination of groundwater recharge parameters,namely temperature,elevation,salinity and excess air,in addition to resolving the potential for contamination,degradation and unsaturated zone effects.This review explores the fundamentals of CFC-11,CFC-12,CFC-113 and SF6 as environmental tracers of groundwater age and recommends complementary techniques throughout.Once this relatively simple and inexpensive technique has been used to determine initial concentrations at the recharge zone,setting the groundwater dating ‘clock’ to zero,this review then explores the meaning of groundwater ‘age’ in relation to measured environmental tracer concentrations.It is shown that the CFCs and SF6 may be applied to a wide-range of hydrogeological problems and suggests that environmental tracers are particularly powerful tools when integrated with numerical flow and transport models.

关键词： Hydrogeology Environmental tracers Groundwater dating

通过地震反射、大地电磁、磁力和重力资料的结构耦合的联合反演及多谱融合开展地球物理综合研究：以巴西海域桑托斯盆地为例

在线全文

学校读者我要写书评

暂无评论

石油地质科技动态 2014年第1期 63-84页

作者： l.a. Gal.a.do

应用交叉梯度联合反演（crossgradient joint inversion）和地质谱可视化方法（geospectral visualization）对沿着巴西东南部大陆边缘桑托斯盆地海域内一条162km长剖面采集的地震反射、大地电磁、重力和磁力资料进行了综合研究。研究... 详细信息

应用交叉梯度联合反演（crossgradient joint inversion）和地质谱可视化方法（geospectral visualization）对沿着巴西东南部大陆边缘桑托斯盆地海域内一条162km长剖面采集的地震反射、大地电磁、重力和磁力资料进行了综合研究。研究区内主要的勘探目的层包括前寒武纪破裂结晶基底的顶部、其上覆的盐下层和盐层／碳酸盐岩沉积地层以及盐上沉积盖层。通过联合反演获得了各套地层清晰的图像，与以往通过单独的2D地震反射资料处理和2D大地电磁成像建立的模型相比．其成像品质有了明显的改善。此外，通过这些模型的多谱融合（multispectral fusion）还得出了单个图像，根据这个图像可以开展有严格约束的地质解释，有助于更好地认识盆地的建筑结构。我们认为，联合反演和图像融合是高效地球物理综合研究的未来发展方向。

关键词：地震反射资料联合反演大地电磁物理综合重力资料西海域盆地结构耦合

Burden, risk assessment, surveil.a.ce and management of SARS-CoV-2 infection in health workers:a scoping review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Infectious Diseases of Poverty 2020年第5期9卷 1-11页

作者： Federica calò Antonio Russo Clarissa Camaioni Stefania De Pascalis Nicola Coppola Department of Mental Health and Public Medicine-Infectious Diseases Unit University of Campania Luigi VanvitelliL.Armanni 580131 NaplesItaly

Background:Health workers(HWs)are at increased risk for severe acute respiratory syndrome-coronavirus-2(SARS-CoV-2)infection and a possible source of nosocomial transmission clusters.Despite the increased risk,the best surveil.a.ce strategy and management of exposed HWs are not yet well known.The aim of this review was to summarize and critically analyze the existing evidence related to this topic in order to support public health strategies aimed at protecting HWs in the hospital setting.Main text:A comprehensive computerized literature research from 1 January 2020 up to 22 May 2020 was made to identify studies analyzing the burden of infection,risk assessment,surveil.a.ce and management of HWs exposed to SARS-CoV-2.Among 1623 citation identified using MEDlINE,Embase,Google Scholar and manual search,we included 43 studies,14 webpages and 5 ongoing trials.Health workers have a high risk of acquiring infection while caring for coronavirus disease 2019(COVID-19)patients.In particular,some types exposures and their duration,as well.a. the inadequate or non-use of personal protective equipment(PPE)are associated with increased infection risk.Strict infection prevention and control procedures(IPC),adequate training programs on the appropriate use of PPE and close monitoring of HWs with symptom surveil.a.ce and testing are essential to significantly reduce the risk.At the moment there is not enough evidence to provide precise indications regarding pre-exposure prophylaxis(PREP)and post-exposure prophylaxis(PEP).Conclusions:During the spread of COVID-19 outbreak,numerous published papers investigated the epidemiology,risk assessment and prevention and control of SARS-CoV-2.However,more high-quality studies are needed to provide valid recommendations for better management and for the clinical.a.d microbiological surveil.a.ce of healthcare personnel.

关键词： Healthcare worker Health worker Risk assessment Surveil.a.ce Management COVID-19

在线全文

学校读者我要写书评

暂无评论

有效应对挑战，实现家禽业可持续发展

中国禽业导刊 2016年第18期33卷 13-13,15页

作者： l.a. den Hartog 荷兰瓦格宁根大学

一家禽产品产量和市场需求持续增加禽肉和禽蛋作为全球优质动物蛋白产品，近年来市场需求量显著增加。FAO数据显示：2015年全球禽蛋产量约为7000万吨，禽肉产量1．12亿吨。国际饲料工业联合会预测：目前全球饲料产量约10亿吨，其中45... 详细信息

一家禽产品产量和市场需求持续增加禽肉和禽蛋作为全球优质动物蛋白产品，近年来市场需求量显著增加。FAO数据显示：2015年全球禽蛋产量约为7000万吨，禽肉产量1．12亿吨。国际饲料工业联合会预测：目前全球饲料产量约10亿吨，其中45％是家禽饲料。

关键词：家禽业可持续发展市场需求量产品产量禽肉产量动物蛋白数据显示饲料产量

Direction of industrial policy in the small towns

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Direction of industrial policy in the small towns

Rice spouted bed for manufacturing inclusion complexes of Endopleura uchi l extracts in β-cyclodextrin

作者： Bubenova l.a. Kuibyshev branch of Novosibirsk State Technical University 632387 Novosibirsk regionKuibyshev town Kainskay78Russia

The given work opens the essence of the smalltown, the types of small towns by the character of their activity and the directions of the industrial policy. The specialattention is given to the industrial policy of the...

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Particuology 2019年第1期17卷 208-215页

作者： l.V.D. Freitas A.C.R. Montes E.I.A. Campos E.C. Conceicao l.a. Tacon A.D. lanchote l.a.P.Freitas Facul.a.e de Ciencias Farmaceuticas de Ribeirao Preto University of Sao PauloVia do Cafe s/n14040-903Ribeirao PretoSPBrazil

Uxi (Endopleura uchi) is a plant from the Brazil.a. Amazon. It has many biological.a.tivities that are attributed to its main active component, bergenin (BG), which has low water solubility. The aim of this work was to obtain β-cyclodextrin (β-CD) inclusion complexes of uxi using lyophilized cooked rice as the solid substrate. The process was studied using a Box–Behnken design with the solution feed rate, molar ratio of β-CD to BG, and rice bed l.a. as factors. These factors greatly affected the product bulk density, angle of repose, water content, and BG content, loss, and water solubility. The optimum process conditions determined using a desirability functions methodology were an extract feed rate of 1 ml/min, a ratio of β-CD to BG of 3:1, and a substrate l.a. of 100 g. The predicted values under the optimum conditions were close to the experimental results of a water content of 5.8%± 0.2%, BG content of 985.7 ± 15.4 μg/g, BG water solubility of 2230.2 ± 21.1 μg/ml, and BG loss of 1.2%± 0.1%. These results confirm that spouted beds are an important tool for rapid, one-step preparation of pharmaceutical β-CD inclusion complexes in a solid form.

关键词： Bergenin Chromatography Yield Active loss Solubility

小型低水头坝围堰拆除设计的流量频率分布选择

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

水利水电快报 2011年第7期32卷 31-37页

作者： l.a.可汗毛红梅

建围堰是水坝安全拆除的第1步。小型低水头坝拆除所需时间通常为几个月。为减少围堰修建费用，通常需要在低水时期进行水坝拆除，因此围堰的设计应根据水坝拆除期间相应的河流流量系列而不是全年流量系列进行。对近期拆除的俄勒冈州桑迪... 详细信息

建围堰是水坝安全拆除的第1步。小型低水头坝拆除所需时间通常为几个月。为减少围堰修建费用，通常需要在低水时期进行水坝拆除，因此围堰的设计应根据水坝拆除期间相应的河流流量系列而不是全年流量系列进行。对近期拆除的俄勒冈州桑迪（Sandy）河上马莫特（Marmot）坝的时均和日均流量记录，按4种拆坝期限进行分析，期限长达1～4个月（7-10月）。为代表现场的最大流量系列，将三一矩比率图和概率图相关关系系数法用来选择皮尔逊Ⅲ型，二参数和三参数的对数正态概率分布函数。从水文工程角度看，建议拆坝的最优时间期限为3个月（7～9月）。根据年最大流量系列估算的流量设计值较高，会导致围堰设计不经济。

关键词：围堰围堰拆除拆除设计小型低水头坝

EPMA IN RUSSIAN SIBERIA FOR THE GEOlOGICAl.a.D ENVIRONMENTAl RESEARCH

在线全文

学校读者我要写书评

暂无评论

EPMA IN RUSSIAN SIBERIA FOR THE GEOLOGICAL AND ENVIRONMENTAL...