Numerical study on suspended sediment concentration in Jiulong Estuary-Xiamen Bay and sediment transport mechanism in tidal inlets with multi-fork

基于环境流体动力学模型(Environment Fluid Dynamic Code/EFDC)水动力和泥沙模块,该文针对九龙江口-厦门湾水域潮动力强、浅滩面积大的特点建立二维潮流泥沙数学模型并利用实测数据进行校验。模型精简适用,成功反演了该水域的水动力场和悬沙浓度场,并能正确反映浅水区域的水沙运动特征。结果表明:在潮流作用下,厦门湾水体中悬沙浓度由外向内递增,悬沙随着潮流的涨落在湾内外作中-长距离的往复运动。湾内特别是浅滩区,大潮期悬沙浓度大于小潮期且浓度随潮变化明显,小潮期悬沙场则较为稳定。采用抓斗式挖泥船(源强Q=7.5 t/h)在翔安东南侧浅滩疏浚作业对邻近保护区基本无影响,但翔安南部"五岔口"型潮汐汊道存在能远程输运近岸疏浚泥沙的"泥泵式"水动力场,促使形成环绕厦门岛东海域的带状悬沙分布,该文进一步揭示了形成该分布的水动力机制。增大疏浚强度可导致白海豚保护区被污染,悬沙带宽度增大,浓度上升。Based on hydrodynamic and sediment transport module of Environment Fluid Dynamic Code/EFDC, a 2-Dimensional mathematical model was applied to the simulation of tidal current and sediment transport in Jiulong Estuary-Xiamen Bay, which was set up with full consideration of the strong tide and large-area shoal in the study area. The model was calibrated and verified using observational data and the simulation results agreed with measured data well, which successfully re-acted the hydrodynamic field and suspended sediment transport in this area, including that of the shoal area. The research shows that, mainly controlled by tidal current, suspended sediment concentration(SSC) increases progressively from outside to inside of Xiamen Bay and suspended sediments move forth and back as tidal currents flow rectilinearly along channels. Inside the bay, especially in shoal area, SSC in spring season fluctuates tidally and is much higher than that in neap season which remains lower and more stable. Dredging in the shoal area positioned to the south east of Xiang'an using grab dredger with source strength of 7.5 t/h almost has no effect on the adjacent protection zone, however, the water area with five-forks positioned to the south of Xiang'an exists a dredge-pump-like hydrodynamic field, through which dredging-produced sediments can be transported in long distance. The special hydrodynamic field leads to the formation of ribbon-pattern distribution of suspended sediments located in the eastern waters of Xiamen island and the hydrodynamic mechanism of it is revealed. Amplifying dredging intensity can result in the pollution of White Dolphin Protection Zone, broadening of ribbon-pattern distribution and increasing of the SSC.国家自然科学基金项目(41406121)~

Experimental Study of the Abalone Shell on Cataract induced by Oxidative Stress

目的研究石决明提取物对体外培养的晶状体氧化应激性白内障形成的作用及机制。方法离体培养小鼠晶状体,应用不同浓度的石决明提取物预孵育晶状体24h后,加入1mm过氧化氢,继续培养3小时后恢复正常培养,72小时后观察小鼠晶状体混浊程度,测定晶状体组织培养液中的乳酸脱氢酶(LDH)含量,晶状体组织中还原型谷胱甘肽(GSH)含量及超氧化物歧化酶(SOD)活力。结果石决明提取物在1~2 mg/ml浓度范围内减轻氧化应激造成的晶状体混浊,减少晶状体LDH的释放,提高组织内GSH含量和SOD活力。结论石决明提取物可减轻氧化应激白内障的形成,其作用主要与石决明提取物提高内源性抗氧化系统有关。Objective To study the effect of the abalone shell extract on oxidative stress induced cataract formation and its mechanism in cultured mouse lens in vitro. Methods The cultured mouse lens were pretreated with the abalone shell extract in different concentrations for24 hours,and then 1mm hydrogen peroxide was added and continued incubating for 3 hours,and they were changed to normal culture media.After 72 hours,the opacity of each lens was observed under an anatomical microscope,the content of lactate dehydrogenase( LDH)leakages,the content of the reduced glutathione( GSH) and activity of superoxide dismutase( SOD) in lens tissue were assayed. Results Abalone shell extract in the concentration range of 1 ~ 2 mg / ml reduced the lens opacity caused by oxidative stress,alleviated the release of LDH,and increased GSH content and SOD activity in cultured lens. Conclusion Abalone shell extract can alleviate the oxidative stress induced cataract formation,and this effect is mainly related to its improvement of the endogenous antioxidant system in lens.2012年福建省卫生厅中医药科研专项课题(No.WST201210);; 2013年福建省卫生厅中医药科研专项课题(No.wzhw201302);; 2014年厦门市科技局科技惠民项目课题(No.3502Z20144030

一种双工位激光焊接机及带涂层薄板激光焊接方法

本发明提供一种双工位激光焊接机及带涂层薄板激光焊接方法，包括机床X轴组件、机床Y轴组件、机床Z轴组件、进料传送带、自动上料架、可移动式出料传送带、控制面板、焊接夹具；机床X轴组件为双导轨形式，固定在地面，在其上安装有机床Y轴组件，可沿X轴方向运动，机床Z轴组件安装在机床Y轴组件上；控制面板安装在机床Y轴组件端头；自动上料架设置在机床外侧，然后依次设置进料传送带，焊接夹具以及可移动式出料传送带，安装在地面上，可实现二维板材拼焊和三维结构件焊接的双工位加工。采用大圆轨迹和小圆轨迹的组合以及设定的工艺参数，实现带涂层板材的焊接。本发明能够降低设备购置成本、提高焊接的效率

一种激光焊接中抑制烟尘及飞溅装置

本实用新型提供一种激光焊接中抑制烟尘及飞溅装置,包括后压脚,前压脚,吹气板,集烟罩,烟尘净化机,竖向气帘,横向气帘和侧轴保护气嘴；焊接夹具中的前压脚、后压脚均为空腔结构,两端有堵头,吹气板和集烟罩分别安装在夹具的两侧,通过中心吹气+两侧吸气的方式提高焊接烟尘吸收效果,同时,通过侧轴保护气与横向、竖向气帘的组合,避免飞溅物向上运动。本实用新型从大幅面板材焊接时烟尘和飞溅物抑制的角度出发,对焊接设备进行一些优化工作来减少焊接加工对环境及设备的危害

一种可实现送丝异常检测的激光焊接装置

本实用新型提供一种可实现送丝异常检测的激光焊接装置,包括拉力弹簧,连接座,编码器、送丝嘴二号安装座,送丝嘴,接触开关,接触开关安装座,送丝嘴一号安装座,立杆,限位螺钉,横杆,立杆固定座,限位块,横杆固定座,弹簧固定座；通过拉力弹簧和限位螺钉的作用,使得送丝嘴呈现柔性连接,当送丝产生粘丝或者干涉时,送丝嘴和送丝嘴二号安装座运动,触发接触开关；当导丝管被挤压、弯折角度过大或者送丝嘴产生烧熔时,送丝阻力过大造成不正常的送丝状态,送丝速度被编码器检测到。本实用新型用来检测送丝不通畅、粘丝等送丝异常的情况,发生送丝异常时将信息反馈于焊接机控制系统,避免因送丝问题影响加工质量、损坏设备

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