Real-Time Stress Measurements in Germanium Thin Film Electrodes during Electrochemical Lithiation/Delithiation Cycling

An in situ study of stress evolution and mechanical behavior of germanium as a lithium-ion battery electrode material is presented. Thin films of germanium are cycled in a half-cell configuration with lithium metal foil as counter/reference electrode, with 1M LiPF6 in ethylene carbonate, diethyl carbonate, dimethyl carbonate solution (1:1:1, wt%) as electrolyte. Real-time stress evolution in the germanium thin-film electrodes during electrochemical lithiation/delithiation is measured by monitoring the substrate curvature using the multi-beam optical sensing method. Upon lithiation a-Ge undergoes extensive plastic deformation, with a peak compressive stress reaching as high as -0.76 +/- 0.05 GPa (mean +/- standard deviation). The compressive stress decreases with lithium concentration reaching a value of approximately -0.3 GPa at the end of lithiation. Upon delithiation the stress quickly became tensile and follows a trend that mirrors the behavior on compressive side; the average peak tensile stress of the lithiated Ge samples was approximately 0.83 GPa. The peak tensile stress data along with the SEM analysis was used to estimate a lower bound fracture resistance of lithiated Ge, which is approximately 5.3 J/m(2). It was also observed that the lithiated Ge is rate sensitive, i.e., stress depends on how fast or slow the charging is carried out. (C) The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited. All rights reserved.

Studies on Carbon Mediated Paste Screen Printed Sensors for Blood Glucose Sensing Application

Ready-to-use screen printed glucose sensors are fabricated using Prussian Blue (PB) and Cobalt Phthalocyanine (CoPC) mediated carbon inks as working electrodes. The reference and counter electrodes are screen printed using silver/silver chloride and graphitic carbon paste respectively. The screen printed reference electrodes (internal reference electrode (IRE)) are found to be stable for more than 60 minutes when examined with saturated calomel electrode. Optimal operating voltage for PB and CoPC screen printed sensors are determined by hydrodynamic voltammetric technique. Glucose oxidase is immobilized on the working electrodes by cross-linking method. PB mediated glucose sensor exhibits a sensitivity of 5.60 mA cm(-2)/mM for the range, 10 to 1000 mu M. Sensitivity of CoPC mediated glucose sensor is found to be 5.224 mu A cm(-2)/mM and amperometeric response is linear for the range, 100 to 1500 mu M. Interference studies on the fabricated glucose sensors are conducted with species like uric acid and ascorbic acid. PB mediated sensors showed a completely interference-free behavior. The sensing characteristics of PB mediated glucose sensors are also studied in diluted human serum samples and the results are compared with the values obtained through standard clinical method. The co-efficient of variation is found to be less than 5%. (C) 2015 The Electrochemical Society. All rights reserved.

Experimental study on pore pressure in rock-soil slope during reservoir water level fluctuation

A test system was developed for measuring the pore pressure in porous media, and a new model was devised for the pore pressure testing in both saturated and unsaturated rock-soil. Laboratory experiments were carried out to determine the pore pressure during water level fluctuation. The variations of transient pore pressure vs. time at different locations of the simulated rock-soil system were acquired and processed, and meanwhile the deformation and failure of the model are observed. The experiment results show that whether the porous media are saturated or not, the transient pore pressure is mainly dependent on the water level fluctuation, and coupled with the variation of the stress field.

Evaluación productiva y reproductiva de un hato criollo lechero (Reyna) en el trópico seco de Nicaragua

El presente trabajo se realizó con el objetivo de estudiar el efecto de distintos factores ambientales (año de parto, época de parto y número de parto) sobre el comportamiento, productivo y reproductivo de un hato criollo lechero Reyna bajo condiciones del trópico seco en la finca "El Pino" Rivas, Nicaragua. Además se cuantificó la repetitividad de las distintas características y se clasificó las vacas en base a la habilidad probable de producción. Se analizaron 31 registros productivos y reproductivos correspondientes al periodo de 1982 a 1989. Las características estudiadas fuero producción de leche total (PLTOT); producción de leche ajustada a 305 días (PL305), largo de lactancia (LARLA) intervalo entre partos (IEP) y edad al primer parto (EPP). En los análisis se utilizó el procedimiento de minimos cuadrados. Mediante análisis de varianza se evaluó el efecto del año de parto, época de parto, número de parto y la interacción año de parto por época de parto, sobre las características PLTOT, PL305, LARLA e IEP, para la EPP se estudió el año de nacimiento de la vaca (ANACV). Este análisis mostró un efecto altamente significativo (P<0.01) del año de parto sobre las características estudiadas, la época de parto resultó no significativa para todas las variables excepto para LARLA, el número de parto resultó altamente significativo (P<0.01) para las características PLTOT, PL305 e IEP y para LARLA resultó no significativo. LaS medias de mínimos cuadrados obtenidas en este estudio fueron de 1377.82±27.79 kg, 1363.20±25.38 Kg, 266.55±3.83 días, 387.74±4.60 días y 1149.15±18.75 días para PLTOT, PL305, LARLA, IEP y EPP respectivamente. Los valores de repetitividad para PLTOT, PL305, LARLA e IEP fueron de 0.18±0.06, 0.17±0.06, 0.09±0.06 y 0.08±0.08 respectivamente. Resultando ser inferiores a los reportados por otros investigadores para el criollo en América Latina.

1989年3月和8月太阳大事件的日地系统整体行为研究

<正> 1989年3月日面出现了近四十年来最大的黑子群,发生了剧烈的太阳活动,产生了重大的地球物理效应。对这些事件的联测取得了大量日地物理的资料。为了推动进一步的分析和研究,中国科学院第22周太阳活动峰年日地系统整体行为研究专家组于1990年4月23日至26日在北京召开了“1989年3月和8月重大日地事件观测与分析研

Unions, Monetary Shocks and the Labour Market Cycle

Published as an article in: Economic Modelling, 2011, vol. 28, issue 3, pages 1140-1149.

Paciano II: the report of a conversation on whaling and science, 1-3 March 2008 (Paciano, Umbria)

In 2006 the UK-based charity, Global Ocean, with local support from the Third Millennium Foundation, convened a Conversation among specialists about the problems facing the conservation of whales. Called "A consultation on whaling", this gathering was held in the ancient village of Paciano, in Umbria near the border with Tuscany, 15 – 17 October 2006. There were 15 participants from 11 countries. Dr Kees Lankester served as moderator. The outcome was an Aide Memoire which served to guide the participants in the run-up to the 2007 meeting of the International Whaling Commission (IWC), held in Anchorage, Alaska, in June. One point of agreement was that a second consultation should be held in the months following the Anchorage meeting, involving some but not necessarily all of the participants in the first, but concentrating this time on scientific issues – especially those encountered in the Scientific Committee of the IWC –with particular attention to informing a wider public about those scientific activities in relation to the problems confronting the IWC and the views of scientists about them. This document is the report of that Conversation, referred to as Paciano II. The moderator was Dr Giuseppe Notarbartolo di Sciara and the Report was written by Kieran Mulvaney in consultation with all participants, and with reference to an Aide Memoire prepared by the Rapporteur, Dr Russell Leaper. The sponsor and organisers have agreed with the general sentiment expressed by participants in Paciano II that further such conversations should be held at roughly yearly intervals and they will try to satisfy that desire. Although these future gatherings would be concerned with the living ocean they would not necessarily be restricted in future to consideration of whales and whaling. Discussions are on-going for selection of a theme which is of both scientific interest and practical concern for conservation of marine life and management of the uses of ocean space. (Document has 18 pages)

亚热带山地景观尺度植被-环境关系的空间格局分析-以三峡大老岭地区为例

本文主要通过大量的植物群落学调查和植被、环境状况的数量分析，分别从植物区系、森林群落及其主要木本物种、干扰和物种多样性五个方面分析了三峡大老岭地区山地植被景观的空间格局及其与环境因子的关系，结果表明： 1） 植物区系：科的分布区类型以热带性质为主;属一级温带性质明显，北温带、东亚和泛热带诸分布类型突出;区系上属于华中植物区系地区的东部。 2） 在垂直梯度上：种子植物属热带分布诸类的比例自海拔400至800米（～1100米）之间呈上升趋势，然后下降;温带分布的第8、9、10、11类随海拔而上升;地中海－中亚中心分布的第12、13类只见于比较干热的河谷地带;东亚分布和中国特有属在海拔900～1100m和1600～1800m段取得小的峰值;世界分布属的比例随海拔而上升，蕨类植物属则相反。 分别用种子植物属的分布型比列构成，和全部521个属的种类数量，对15个海拔段作聚类分析：前者首先反应了海拔1100～1200m处的划分，与植被干扰状况的垂直分布差异一致;后者强调了海拔900/1000m和1800/1900m 处的分异，可能反映了地带性常绿阔叶林基带／常绿落叶阔叶混交林带，和常绿落叶阔叶林带／落叶阔叶林带的分异。 3） 对本地区森林植被的数量分类结果表明：基本上可以分为中低海拔次生落叶 针阔混交林和中高海拔山地常绿落叶阔混交林两大群。第一群主要包括栓皮栎林－杉木林－马尾松林组（低海拔段）和短柄抱栎林－锥栗林组（中低海拔段）。第二群包括中低海拔沟谷常绿阔叶林组、中海拔段常绿落叶阔叶混交林组和高海拔段米心水青冈林－茅栗林组。 DCCA排序区分了11个群落类型或群落组。采用的7个地貌因子变量中效果显著的可归纳为三组：①海拔，主要反映热量和降水梯度;②坡度和坡位，可能主要反映土壤厚度及其水分和养分状况;③坡向及坡位，反映光照条件。其中植被格局的海拔梯度效应最显著。沿海拔梯度分段分析上述诸因子对植被格局差异影响的垂直分布，表明海拔因子的局部效应在海拔600－800m和1500－1700m段最显著;坡向的效应在海拔1600m以上最突出;坡面、坡位、坡形、坡度等因子的作用在海拔中部最大。对植被格局影响因子的贡献进行定量分离，表明地形对对大老岭森林格局具有强烈的控制作用。 4） 对大老岭森林植被275个主要的木本种类进行TWINSPAN分类，得到16个种组;DCCA排序结果将上述16组合并为8群，两方面都主要反映了沿海拔和坡位＋坡向的分化;海拔中部的局部地形差异导致物种组的分化比两端更细致和强烈。 根据物种生活型及其在植物群落中的地位，分6个种组进行排序和环境解释，表明：①尽管低海拔地段受到强烈人为干扰，常绿种类仍显示了数量和性质沿海拔梯度的变化;②珍稀物种在海拔梯度上形成两个相对集中的区段，大致对应于山地常绿落叶阔叶混交林带的上下边缘;③先锋树种在中低海拔的中上坡位富集;④在中、高海拔的中低坡位，落叶的乔木伴生种显示了极大的多样性;⑤为数不多的针叶树种在海拔和局部地形梯度上也有明确分异;⑥它们和落叶的栎（Quercus）、栗（Castanea）、水青冈（Fagus）、鹅耳枥（Carpinus）属物种在大老岭地区不同地形部位的植被中起着主要的建群作用。 具体统计海拔梯度上，常绿和落叶的乔、灌木4类物种分布的种数变化表明：海拔1100m以下人为活动干扰与木本物种多样性呈一致的负相关;海拔1100m以上常绿种减少与与落叶种的增加形成对照;1100～1700m之间是落叶乔木种最丰富的地段，海拔1700m以上四类物种数量急剧下降，与山顶脊附近生境多样性降低、植物群落类型趋同有关。另外，典型亚热带的棕榈和蕉只见于海拔1000m以下;针叶树种以海拔1150m左右为界分成两组。前述4类物种的分布边界在海拔850～1050m和海拔1650～1750m之间形成比较明显的峰值，基本对应着山地常绿落叶阔叶混交林带的上下边缘。 根据海拔分布范围，将样方中出现的558种木本植物按常绿乔／灌种和落叶乔／灌种分别分成5个热量生态类群。统计各自的面分比表明：a. 落叶灌木种的多样性分布重心在海拔梯度上的位置比落叶乔木种高，常绿种则相反，因此灌木和类的分布特征能更好的反映次生环境中的植被－气候关系;b. 在海拔850～1850m的木本物种形成巨大的多样性，仅出现于这一段的物种也很可观;亲缘物种的分化和替代突出，反映其对生物多样性发生和维持的意义重大;c. 亚热带中山地带对落叶种生物多样性的意义远大于常绿种。 5）统计全部群落样方内枯立木、倒伏木、断头木和伐桩四类受干扰木的大小、数量、物种以反映地形对干扰的影响：①枯立木以2～15cm径级个体为主，小径级的树种选择性不强，主要分布在山南坡口上坡位，海拔1800m以上尤多，在陡峭的坡地中部减少;其大径级个体的物种构成和分布格局反映了与生境干旱有关干扰的存在。②倒伏木主要分布在海拔1200～1800m之间坡面中部和顶脊两侧，发生频率与坡度成正比;坡地中部以中、小径级阳性树种为主，山坡顶脊两侧的倒伏木则多为大径级的群落优势种。③断头木主要分布在海拔1200～1700m，和海拔1900m以上。小径级的断头木分布格局接近于枯立木，较大径级的断头木则多与倒伏木的分布相关，断头木中少有典型的阳性树种，主要由林下荫耐种构成。④人为砍伐的伐桩主要为中大径级的植被建群种或优势种个体，在海拔1000m以下，1100-1200m和1600-1800m形成三个峰值，其分布主要与人口密度、生产方式、林木种类以及交通运输便捷程度有关，通常沟谷和山脊线上的伐桩密度较大。大老岭地区人为干扰主要反映在海拔1100m以下，自然干扰的格局在海拔1100m以上才得到反映。 6）在不同取样尺度上，对大老岭地区森林群落各层次α多样性和β多样性的空间格局分析表明：i. 乔木层α多样性在海拔1200-1800m之间取值较高，灌木、草本层α多样性的垂直梯度不显著，但在海拔1200-1800m之间的波动变化较为剧烈，南坡面有最丰富的灌木层多样性而西坡乔木层的物种最丰;从植被整体上，海拔1000m以下物种丰富度较低，1000-1700m之间变化剧烈，1700m以上丰富度水平较高。ii. 海拔1000-2000m之间94个样方中，乔、灌、草三层多种生物多样性指数变化影响因子的大小顺序是：坡位>海拔>坡向>坡面>坡度>坡形。乔、灌、草各层几种多样性指数在多维的地形因子梯度上形成各异的分布格局，反映了山地物种多样性格局控制因子的多样性和多尺度，及局部地形因子对景观尺度上生物多样性空间格局的强烈影响。iii.对海拔1050m和1670m处植被α多样性的变尺度分析表明：随取样尺度增大，低海拔乔木、灌木层α多样性增长速率比高海拔大;后者草本层的多样性增长比较快。海拔1050m处群落各层的α多样性在800m~2尺度上渐近稳定;海拔1670m处，400m~2尺度上各层α多样性指数已基本稳定。 南、北、西坡面β多样性沿海拔梯度大致减少，在海拔1600m以上更明显，在海拔梯度中部变化剧烈。反映不同坡面上群落间异质性水平是：西坡>北坡>南坡。 在对植被、环境上述各个方面的格局特征分析基础上，对三峡地区侵入岩山地类型建立了一个综合的植被景观格局模式。 文章最后就两个景观尺度植被－环境的综合性问题进行了讨论：1）气候、植物区系、植被和物种分布等对老岭以至于三峡地区和亚热带山地常绿落叶阔叶混交林带的位置、宽度的反映;和气候、地形、干扰等因子对这一生态过渡带格局和动态的影响;2）三峡地区生物多样性垂直分布的特征、维持和变化的现代机制，以及保护的重点和策略