995 resultados para 301-U1301B


Relevância:

10.00% 10.00%

Publicador:

Resumo:

[EN] In this paper a short basque text included in a french comedy from XVIIth century is published and analyzed. That text appears in the second scene ofthe Raymond Poisson's comedy, "Le Poète Basque". It seems difficult to specify which variety of Basque is used by Poisson; anyway, I try to demonstrate that text shows characteristics of the dialects of Labourd and Low Navarre.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This study examined the economic potential of fish farming in Abeokuta zone of Ogun State in the 2003 production season. Descriptive statistics cost returns and multiple regression analysis were used in analyzing the data. The farmers predominantly practiced monoculture. Inefficiency in the use of pond size, lime and labour with over-utilization of fingerlings stocked was revealed by the study. The average variable cost of N124.67 constituted 45% of the total while average fixed cost was N149.802.67 per average farm size. Fish farming was found to be a profitable venture in the study area with a net income of N761, 400.58 for an average pond size of 301.47sq.m. Based on these findings, it is suggested that for profit maximization, the fish farm will have to increase the level of their use of fingerlings and fertilizers and decrease the use of lime labour and pond size

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pond Action is an independent freshwater conservation project which was started in 1987. It is based in the School of Biological and Molecular Sciences in Oxford Polytechnic and has five full-time staff with two senior advisors. The main aim of Pond Action's work has been to promote the conservation of ponds by creating a sound, scientific basis for pond conservation. An essential aspect of this work is the need to make the results of scientific work available and understandable to everybody concerned with pond conservation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The influence upon the basic viscous flow about two axisymmetric bodies of (i) freestream turbulence level and (ii) the injection of small amounts of a drag-reducing polymer (Polyox WSR 301) into the test model boundary layer was investigated by the schlieren flow visualization technique. The changes in the type and occurrence of cavitation inception caused by the subsequent modifications in the viscous flow were studied. A nuclei counter using the holographic technique was built to monitor freestream nuclei populations and a few preliminary tests investigating the consequences of different populations on cavitation inception were carried out.

Both test models were observed to have a laminar separation over their respective test Reynolds number ranges. The separation on one test model was found to be insensitive to freestream turbulence levels of up to 3.75 percent. The second model was found to be very susceptible having its critical velocity reduced from 30 feet per second at a 0.04 percent turbulence level to 10 feet per second at a 3.75 percent turbulence level. Cavitation tests on both models at the lowest turbulence level showed the value of the incipient cavitation number and the type of cavitation were controlled by the presence of the laminar separation. Cavitation tests on the second model at 0.65 percent turbulence level showed no change in the inception index, but the appearance of the developed cavitation was altered.

The presence of Polyox in the boundary layer resulted in a cavitation suppression comparable to that found by other investigators. The elimination of the normally occurring laminar separation on these bodies by a polymer-induced instability in the laminar boundary layer was found to be responsible for the suppression of inception.

Freestream nuclei populations at test conditions were measured and it was found that if there were many freestream gas bubbles the normally present laminar separation was elminated and travelling bubble type cavitation occurred - the value of the inception index then depended upon the nuclei population. In cases where the laminar separation was present it was found that the value of the inception index was insensitive to the free stream nuclei populations.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Measurements of friction and heat transfer coefficients were obtained with dilute polymer solutions flowing through electrically heated smooth and rough tubes. The polymer used was "Polyox WSR-301", and tests were performed at concentrations of 10 and 50 parts per million. The rough tubes contained a close-packed, granular type of surface with roughness-height-to-diameter ratios of 0.0138 and 0.0488 respectively. A Prandtl number range of 4.38 to 10.3 was investigated which was obtained by adjusting the bulk temperature of the solution. The Reynolds numbers in the experiments were varied from =10,000 (Pr= 10.3) to 250,000 (Pr= 4.38).

Friction reductions as high as 73% in smooth tubes and 83% in rough tubes were observed, accompanied by an even more drastic heat transfer reduction (as high as 84% in smooth tubes and 93% in rough tubes). The heat transfer coefficients with Polyox can be lower for a rough tube than for a smooth one.

The similarity rules previously developed for heat transfer with a Newtonian fluid were extended to dilute polymer solution pipe flows. A velocity profile similar to the one proposed by Deissler was taken as a model to interpret the friction and heat transfer data in smooth tubes. It was found that the observed results could be explained by assuming that the turbulent diffusivities are reduced in smooth tubes in the vicinity of the wall, which brings about a thickening of the viscous layer. A possible mechanism describing the effect of the polymer additive on rough pipe flow is also discussed.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Estudos demonstram a associação de alterações da apolipoproteína E (ApoE) e do receptor do LDL (RLDL) com a ocorrência de doenças cardiovasculares e dislipidemia. O objetivo principal deste trabalho foi investigar a associação entre genótipos diferenciais da ApoE e do RLDL com a persistência de alterações de variáveis lipídicas em indivíduos jovens acompanhados há 28 anos no Estudo do Rio de Janeiro (ERJ). Através de um estudo longitudinal, tipo coorte, investigou-se 56 indivíduos (35M) em três avaliações. Em A1 (13.301.53 anos), A2 (22.091.91 anos) e A3 (31.231.99). Nas três ocasiões foi realizada avaliação clínica. Em A2 e A3 foram dosados colesterol total, HDL, LDL e triglicerídeos. Em A3 acrescentou-se o estudo dos polimorfismos genéticos da ApoE e do RLDL. Os fragmentos de interesse neste estudo foram amplificados por PCR (polymerase chain reaction) e os genótipos foram identificados através de reações de restrição. As frequências genotípicas de ApoE foram ε3/ε3 (62,5%), ε3/ε4 (25%), ε2/ε3 (5,4%) ,ε2/ε4 (5,4%) e ε4/ε4 (1,8%) e para os genótipos de RLDL foram AA (85,7%), AT (12,5%) e TT (1,8%). O genótipo ε2/ε2 não foi observado. A análise da distribuição dos genótipos de ApoE segundo a permanência de dislipidemia mostrou que todos os indivíduos com genótipo de ApoE dos tipos ε2/ε4 e ε4/ε4 mantiveram pelo menos um lípide alterado em A2 e A3 entretanto, todos os indivíduos com genótipo de ApoE do tipo ε2/ε3 não apresentaram lípides alterados em A2 e A3. Para o genótipo do RLDL não houve diferença significativa. Quando analisadas isoladamente, não foi identificado nenhum resultado significativo em A2 e/ou A3 associado a estes genótipos. O polimorfismo do gene da ApoE esteve associado à permanência de dislipidemia em indivíduos jovens acompanhados em estudo de seguimento longitudinal

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A novel laser resonator for compensating depolarization loss that is due to thermally induced birefringence in active rod is reported. As this new structure being applied to an electro-optic Q-switched LIDA side-pumped Nd:YAG laser operating at a repetition rate of 1000 Hz, substantial reduction in depolarization loss has been observed, the output pulse energy is improved about 56% from that of a traditional resonator without compensation structure. With incident pump energy of 450 mJ per pulse, linearly polarized output energy of 30 mJ per pulse is achieved, the pulse duration is less than 15 ns, and the peak power of pulse is about 2 MW. The extinction ratio of laser beam is better than 10:1, and the beam divergence is 1.3 mrad with beam diameter of around 2.5 mm. (c) 2006 Published by Elsevier B.V.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

探讨了双源共蒸法制备非均匀薄膜的堆积模型,并给出了非均匀膜的沉积速率与两种膜料沉积速率的关系.当两种膜料的沉积单分子大小近似相等或者小分子沉积速率远大于大分子时,可以近似认为混合介质膜的沉积速率等于两种膜料的沉积速率之和;当两种膜料的沉积单分子大小不满足近似相等且两种膜料的沉积速率可比较时,非均匀膜的沉积速率不能简单地用两种膜料的沉积速率之和来近似,它将随两种膜料沉积单分子的大小不同和沉积速率比不同按照不同的规律变化,并在文中给出了不同情况下的非均匀膜的沉积速率变化规律。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

用磁控溅射法制备了顶层分别是Mo膜层和Si膜层的两个系列的Mo/Si多层膜,它们的周期厚度相同但是膜层数各不相同。Mo/Si多层膜的周期厚度和界面粗糙度由小角X射线衍射(SAXRD)曲线拟和得到。用原子力显微镜测量了Mo/Si多层膜的表面粗糙度。在国家同步辐射实验室测量了Mo/Si多层膜的软X射线反射率。通过理论和试验研究,发现Mo/Si多层膜的软X射线反射率主要由周期数和界面粗糙度决定,表面粗糙度对Mo/Si多层膜的软X射线反射率影响较小。

Relevância:

10.00% 10.00%

Publicador:

Relevância:

10.00% 10.00%

Publicador:

Resumo:

植物志的编研是植物学研究领域的基础性工作。植物志既是记载植物“身份"的"户口簿",又是记录和研究植物特征的重要"信息库"。《中国植物志》编研以大规模野外考察与标本采集为基础,以丰富的信息记载为核心,系统研究这些信息并编撰成科学志书,是一项百科全书式的系统工程。《中国植物志》历经四代植物分类学家41年(1918-1959)的准备、45年(1959-2004)的编研,由312位作者和164位绘图人员通力协作完成(其中科学院院士10位),并于2004年全部出版(中文名和拉丁学名的索引于2006年出版)。在编研过程中,采集和查阅植物标本1700余万份,发表新属及新属名称243个,发表新种及新种名称14312个,提出了新的裸子植物和被子植物分类系统,对属、种划分和系统排列进行了深入研究。《中国植物志》是世界上已出版的规模最大和内容最丰富的植物志书,全书5000多万字,总计80卷126册,记载中国维管束植物301科、3408属、31142种,包括9080幅图版,详细总结、记录、澄清了中国所有已知植物的科学名称、研究历史、形态特征、地理分布、系统位置、物种生境、物候期和经济用途等。《中国植物志》是中国半个世纪以来植物学研究的标志性成果。它查明了中国植物资源的基本状况,对科学家深入认识植物世界具有重要学术价值,对陆地生态系统研究将起到重要促进作用,为合理开发利用植物资源提供了重要的科学依据,中国植物学科研和教学队伍也因此得到了壮大,出现了一批享誉国际的优秀植物分类学家。《中国植物志》是植物学研究领域一项开拓性、创新性、系统性、基础性工程,它的完成促进了中国植物学的健康发展,也带动了生物学相关学科的进步,必将对中国和全球生物多样性的可持续发展做出重大贡献并产生深远影响。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

植物志的编研是植物学研究领域的基础性工作。植物志既是记载植物“身份"的"户口簿",又是记录和研究植物特征的重要"信息库"。《中国植物志》编研以大规模野外考察与标本采集为基础,以丰富的信息记载为核心,系统研究这些信息并编撰成科学志书,是一项百科全书式的系统工程。《中国植物志》历经四代植物分类学家41年(1918-1959)的准备、45年(1959-2004)的编研,由312位作者和164位绘图人员通力协作完成(其中科学院院士10位),并于2004年全部出版(中文名和拉丁学名的索引于2006年出版)。在编研过程中,采集和查阅植物标本1700余万份,发表新属及新属名称243个,发表新种及新种名称14312个,提出了新的裸子植物和被子植物分类系统,对属、种划分和系统排列进行了深入研究。《中国植物志》是世界上已出版的规模最大和内容最丰富的植物志书,全书5000多万字,总计80卷126册,记载中国维管束植物301科、3408属、31142种,包括9080幅图版,详细总结、记录、澄清了中国所有已知植物的科学名称、研究历史、形态特征、地理分布、系统位置、物种生境、物候期和经济用途等。《中国植物志》是中国半个世纪以来植物学研究的标志性成果。它查明了中国植物资源的基本状况,对科学家深入认识植物世界具有重要学术价值,对陆地生态系统研究将起到重要促进作用,为合理开发利用植物资源提供了重要的科学依据,中国植物学科研和教学队伍也因此得到了壮大,出现了一批享誉国际的优秀植物分类学家。《中国植物志》是植物学研究领域一项开拓性、创新性、系统性、基础性工程,它的完成促进了中国植物学的健康发展,也带动了生物学相关学科的进步,必将对中国和全球生物多样性的可持续发展做出重大贡献并产生深远影响。