Vertical distribution of zooplankton in the continental slope southwest of Nansha Islands,South China Sea

浮游动物是海洋生态系统物质和能量转移的关键环节,也是渔业资源的重要饵料,其种类组成和数量分布均有明显的垂直分层现象。利用2011年4月在南沙群岛西南大陆斜坡海域开展的18个站点90份样品的调查数据,对该海域浮游动物的垂直分布进行了研究,表明:(1)该海域浮游动物种类组成丰富,共出现18个类群580种(类);(2)浮游动物种类组成垂直变化明显,特定水层出现的种类数占总种数的43.6%,各水层均出现的种类仅占总种数的15.8%;(3)优势种组成复杂,垂直变化明显,单一种类的优势度不高;(4)浮游动物平均密度和湿重生物量分别为206.27Ind/M3、94.03Mg/M3,密度和生物量均以0~2M层和30~75M层较高,沿水深梯度的变化呈明显的双峰型;(5)浮游动物数量的垂直变化主要受温跃层影响,温跃层内浮游动物数量最高,温跃层上方和下方的水层内数量较低;(6)南沙西南大陆斜坡区浮游动物生产力水平较高,表明该海域渔业资源有一定的开发潜力。As dietary organisms of fish stocks,zooplankton is a key link of mass and energy transformation in the marine ecosystem.There are vertical changes in the species compositions and abundances of zooplankton in the water column.Based on 90samples from 18stations collected in April 2011,the vertical distribution of zooplankton in the continental slope to the southwest of Nansha Islands,South China Sea was studied.It was found that the continental slope waters are rich in zooplankton species,with a total number of 580species belonging to 18taxa being recorded.There are obvious vertical variations in the zooplankton species compositions.The numbers of zooplankton species occurring in a specific deep group could take up 43.6%of the total number of species,while the number of species occurring in all deep groups made up only 15.8%of the total number of species.There was no obvious dominant species and the dominancy of any single species was low.The overall mean density and wet biomass of zooplankton were 206.27ind/m3 and 94.03mg/m3 respectively.The higher density and biomass were found in the deep groups of 0—2mand 30—75mand the vertical distribution showed a pattern of double-humped curve.Thermocline was an important factor in the vertical distribution of zooplankton.The abundances of zooplankton in the thermocline layer were higher than those in the upper mixed layer and the water layers bellow the thermocline.Compared to the other regions in the South China Sea,zooplankton abundances were the highest in the continental slope southwest off Nansha Islands,suggesting potentials for fishery development in the region.中央级科研院所基本科研业务费专项资金(中国水产科学研究院南海水产研究所)资助项目(2012TS02); 农业部财政重大专项(NFZX2013); 国家科技支撑计划课题(2013BAD13B06

Preparation and Electrocatalytic Performance of NiCo2O4/Ni Foam for Hydrogen Peroxide Electrooxidation

本文以水热法结合热处理法原位制备了泡沫镍载 NiCo2O4纳米线电极，使用XRD、SEM和TEM对合成的 NiCo2O4纳米线进行了表征，NiCo2O4纳米线直径约80 nm，长度约 3 ~ 5 μm. 使用循环伏安和计时电流法测试了泡沫镍载NiCo2O4纳米线催化H2O2的电氧化性能，结果表明泡沫镍载NiCo2O4纳米线对H2O2电氧化有着优良的催化活性、稳定性和传质性能，在0.3 V电位下0.4 mol·L-1 H2O2和2 mol·L-1 NaOH溶液中氧化电流可达380 mA·cm-2.The electrodes of Ni foam supported NiCo2O4 nanowires were prepared by hydrothermal method, followed by a thermal treatment in air, and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that the NiCo2O4 nanowires had a diameter of about 50 nm with a length up to 3 ~ 5 μm. The catalytic performances of the Ni foam supported NiCo2O4 nanowires for H2O2 electrooxidation were studied by cyclic voltammetry and chronoamperometry. The results show that the Ni foam supported NiCo2O4 nanowires electrode exhibited superior activity, stability, and mass transport property for H2O2 electrooxidation. A current density of 380 mA·cm-2 was achieved at 0.3 V in 0.4 mol·L-1 H2O2 and 2 mol·L-1 NaOH at room temperature.国家大学生创新训练项目、国家自然科学基金项目（No. 51572052）资助作者联系地址：哈尔滨工程大学材料科学与化学工程学院，黑龙江 哈尔滨 150001Author's Address: College of Material Science and Chemical Engineering, Harbin Engineering University,Harbin 150001, Heilongjiang, China通讯作者E-mail：[email protected]

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies