磁性抛光对3D打印微结构的参数影响

对微结构精密加工时要能够控制高低不平的材料去除,以保证不破坏微结构原来的三维形貌特征。通过自行搭建的实验平台对3D打印出来的微结构工件进行抛光实验,主要研究了机床主轴转速、加工间隙、抛光时间和抛光路径等工艺参数对微结构抛光后的三维轮廓材料去除特性以及微结构的保形情况。实验结果表明:微结构保形系数随着抛光时间增加而变小,而主轴转速和加工间隙的变化对保形系数影响较小;采用等高线移动式抛光的保形系数比采用水平移动式大;相同工艺参数抛光对包体状和圆环阵列微结构工件保形效果较好,对三棱锥工件保形效果较差。国家自然科学基金(51675453);;深圳市科技计划项目(JCYJ20160517103720819

股权分置改革的期权分析

本文将股权分置改革本身看做是上市公司拥有的永久性美式看涨期权多头,并运用期权分析框架,分析了股权分置改革时机的选择问题、流通股股东与非流通股股东的博弈、预期与价格跳跃过程,找到了该期权定价公司和提前执行该美式期权的最优执行边界,消除了在股权分置改革过程中出现的一些认识上的误区,并对中国的股权分置改革问题提出了一些政策性建议

Study on Remove of Free-Form Surface Structure by Magnetic Polishing

磁性抛光因柔性工具的工件表面适应性高而具有较好的应用潜力。自行设计抛光工具头,制备磁性抛光体,搭建试验平台,并对不锈钢平面工件进行定点抛光试验,平均去除效率为0.231μm/10min,且工件表面质量得到了很大的改善,验证了该磁性抛光方法的可行性。继而对两种自由曲面结构工件进行抛光：一是采用工具头水平移动式、工具头等高线移动式两种不同的抛光进给运动方式对不同曲率的不锈钢工件进行抛光去除试验,试验证明：两种抛光方式对每个曲率的轮廓均有去除能力,去除量在0.14~1.33μm之间;二是对3D打印的光敏树脂微结构自由曲面定点抛光,单位时间去除效率在8.957~12.587μm/10min之间,且改善了轮廓的光滑度。初步试验表明,磁性抛光方法对两种自由曲面结构均有一定的去除能力,可进一步探索磁性抛光技术应用于自由曲面结构确定性抛光。Magnetic polishing technique has wide application potential due to the high adaptability of flexible tool to the workpiece surface. The relevant polishing tools were developed, and a test platform was established in the paper. The workpiece finish had been greatly improved after spot polishing on stainless steel flat parts, and the average removal efficiency was 0.231μm/10 min, which verified the feasibility of the magnetic polishing method. Then two kinds of free-form surface structures were polished by magnetic polishing method. First, stainless steel parts with different curvatures were polished by two different polishing feed movement ways. Experimental results showed that two polishing methods had the ability to remove the contours of each curvature, and the removal amount falls between 0.14-1.33μm. Secondly, the removal efficiency was between 8.957-12.587μm/10 min after spot polishing the microstructured free-form surface, and the smoothness of the contour is improved. Preliminary experiments showed that the magnetic polishing method had the ability to remove both free-form surface structures, so it can explore further magnetic polishing technology used in deterministic polishing of free-form surface structure.深圳科技计划项目（JCYJ20160517103720819

Physiological responses of three cultivar seedlings of Bougainvillea under drought stress

该研究对勤花三角梅(Bougainvillea buttiana Miss Manila')、樱花三角梅(B.glabra Imperial; Delight')和金心鸳鸯三角梅(B.peruviana; Thimma')三个三角梅品种的幼苗进行人工干旱胁迫,分析了干旱胁迫对三角梅品种的外观形态和生理生化水平的影响,探讨了不同品种三角梅对干旱胁迫的; 适应能力。结果表明:随着干旱时间的延长,三角梅品种的叶片出现下垂、皱缩、变黄、脱落,最后植株死亡;过氧化物酶POD活性先升高后降低,而超氧化物歧; 化酶SOD活性则逐渐降低,降低速度因品种而异;qP值降低、qN值升高、PSⅡ反应中心光化学效率(Fv/Fm)、PSⅡ潜在活性(Fv/Fo)均呈现; 降低。该研究结果为三角梅的栽培应用和品种选择提供了依据。Seedlings of Bougainvillea buttiana Miss Manila', B.glabra Imperial; Delight' and B.peruviana Thimma' were treated to study the physiological; responses under drought stress.The results showed that the plant leaves; began to droop, gradually shrink, yellow in color, and fell off, all of; the treatment seedlings died finally under the long drought.The results; showed that the peroxidase activities(POD) were increased at beginning,; and decreased finally, while the superoxide dismutase(SOD) activities; were gradual decreased, but the reduction rates were different in the; three cultivar seedlings.The research on chlorophyll fluorescence; parameters showed that qP value was decreased, while qN value was; increased, and the photochemical efficiency of PSⅡreaction center(Fv/Fm); and potential activity of PS Ⅱ(Fv/Fo) were decreased under drought; stress.This study provides information for breeding application and; choosing ulltivars of Bougainvillea.厦门市科学技术局资助项

贝塔系数波动状况的实证分析

资本资产定价模型(CAPM)自创立以来得到广泛应用。但对CAPM的实证检验也争议不断。利用上海股票市场90家上市公司的数据作为样本,对CAPM中的贝塔系数的波动状况进行实证研究,结果表明所有股票的贝塔系数波动率都显著异于零,贝塔系数在不同的时期会发生变化。实证分析中如果忽略了这一点,必将导致对CAPM检验的失效

Monitoring system of machining environment based on image recognition

设计实现一种基于图像识别的机床工况监控系统,该系统包括摄像机、dM642下位机以及上位机人机界面3部分。通过优化数字仪表图像处理与识别算法,实时对机床主要配套设备的数字仪表进行图像识别、监测,可准确检测机床的加工环境及机床实际状态参数,并通过以太网与上位机通信,实现远程监控机床环境工况,给机床状态信息管理和维护提供便利。This paper develops a monitoring system of machining environment,which contains cameras,DM642 development board and computer application.By optimizing digital image processing and recognition algorithms,the digital instrument of machine associated equipment are recognized in real time,besides, machining environment and actual status parameters are accurately detected.The computer application communicates with DM642 through ethernet,so that the machining environment is remotely monitored, and information management of machining environment is facilitated.国家科技重大专项(2013Z×04001000-206

Responses of Bougainvillea to Salt Stress

长期盐胁迫处理实验表明,随着nA Cl浓度增加,不同三角梅品种的地上部和地下部生物量均呈下降趋势。与对照相比,盐浓度为5%时,勤花三角梅生物量下降幅度最小,为27.94%;樱花三角梅下降最大,为67.03%。当盐浓度为4%时,樱花三角梅、白苞三角梅和勤花三角梅的光量子产量分别为0.36、0.30和0.36,分别为对照的78.23%、79.64%和74.82%;金心鸳鸯三角梅的光量子产量为0.05,仅为对照的15.53%。白苞三角梅的光化学猝灭系数Q P值随着盐浓度的升高无明显变化;金心鸳鸯三角梅、勤花三角梅和樱花三角梅的Q P值随着盐浓度的升高而降低。4个三角梅品种的抗盐胁迫能力为:白苞三角梅>樱花三角梅>勤花三角梅>金心鸳鸯三角梅。The long-term Na Cl salt stress experiments showed that with the increasing of Na Cl concentration, shoot and root biomass of different Bougainvillea cultivars were decreased.At 5% Na Cl concentration, biomass of ‘Miss Manila' had the least decline of 27.94%; however, ‘Imperial Delight' had the largest decline of 67.03%, compared with the control.When the Na Cl concentration was 4%, the quantum yield of ‘Imperial Delight', ‘Shubhra' and ‘Miss Manila' were 0.36, 0.30 and 0.36, with 78.23%, 79.64% and 74.82% of the control, respectively; the quantum yield of ‘Thimma' was 0.05, only 15.53% of the control.With the increasing of Na Cl concentration, photochemical quenching coefficient q P of ‘Shubhra' had no obvious change; but q P value of ‘Thimma', ‘Miss Manila' and ‘Imperial Delight' decreased significantly.The resistance ability to Na Cl salt stress of four Bougainvillea cultivars was ‘Shubhra' > ‘Imperial Delight'> ‘Miss Manila' > ‘Thimma'.厦门市科学技术局项目(3502Z20124013

Heavy metals contamination in fish from coral reef ecosystem and ecology risk evaluation

为研究海南珊瑚礁区重金属的污染现状,选择鱼类为污染指示物,测定珊瑚礁区的5种鱼体中Cr、Mn、Cu、zn、AS、Pb和Hg 7种重金属的含量,并采用单因子污染指数法(PI)对重金属的污染状况进行了风险评价。研究结果显示,不同鱼类对同种重金属元素的富集能力存在较大差异,同种鱼对不同重金属元素的富集能力也存在差异。珊瑚礁区鱼类重金属的污染程度由强到弱的顺序为:Cr>AS>Mn>Hg>zn>Cu>Pb;鱼类的鳃和内脏器官比肌肉更容易蓄积重金属。珊瑚礁区生物富集作用最明显的为Cr和AS。PI结果表明海南珊瑚礁区鱼体重金属Cr的污染严重,AS中度污染,其他重金属基本无污染或轻度污染。To study the pollution status quo of heavy metals in coral reef ecosystem in Hainan Island,concentrations of heavy metals including Cr,Mn,Cu,Zn,As,Pb,and Hg in wild fish were determined.Single factor pollution index(Pi) was employed to evaluate the heavy metal pollution level.The results showed that enriched degree of the heavy metals in fish can be ranked from high to low as Cr>As>Mn>Hg>Zn>Cu>Pb;heavy metals prefer to be accumulated in gill and viscera.Obvious bioaccumulation of Cr and As in fish of coral reef ecosystem was observed.Pi indicated that coral reef ecosystem in Hainan Island has been heavily polluted by Cr and moderately polluted by As.Other metals have shown no pollution or slight pollution.中国博士后科学基金(2012M510201); 中国科学院百人计划资助项目(2060299); 中国科学院南海海洋研究所知识创新工程领域前沿项目(50601-31); 王宽诚教育基金会对本工作的资

光照条件对长苞铁杉种子萌发与幼苗生长的影响

2004-2006年研究了在不同光照下(100%,50%,25%,10%全日照)长苞铁杉(Tsuga longibracteata)种子萌发率、幼苗存活率、幼苗生物量及其分配比例和幼苗根与叶、生理特性。结果表明,50%全日照条件下,种子萌发率和幼苗存活率最高;幼苗根、茎、叶及总生物量最高;光照的增强促使生物量往地下分配以加强根部吸收水分的能力,并促使地上部分的生物量更多的分配到叶片生长上。随着光强的提高,幼苗叶片叶绿素a、叶绿素b、总叶绿素和类胡萝卜素含量均呈下降的趋势,叶绿素a与叶绿素b比值和类胡萝卜素与总叶绿素比值呈上升趋势。在光强不超过50%时,随着光强的提高,幼苗叶片和细根的MDA含量、SOD和POD活性呈升高趋势;光照强度达到全日照时,叶片MDA含量、SOD和POD活性呈下降趋势。幼苗叶片和细根Pro含量在25%全日照时最低。50%全日照附近是长苞铁杉育苗的合适光照强度

基于表面增强拉曼光谱的合成色素专利蓝V的快速检测

食品安全问题一直是社会和广大群众关注的焦点问题,食品安全现状较为严峻,因此实现食品中有害物质的快速检测具有重要的实际意义。合成色素是一种常见的食品添加剂,然而合成色素的超标添加和非法添加依旧是食品安全中的重要问题之一,极大地危害人民群众的身体健康和食品工业的健康发展。常见的合成色素检测方法,均存在耗时长、费用高等缺点,不适应于合成色素的实时监测和快速筛查。为克服传统方法的缺点,提出利用表面增强拉曼光谱检测技术对合成色素进行检测,该方法具有检测速度快、检测灵敏度高等优点,能够达到现场实时检测的目的。此外,由于拉曼检测方法往往依赖于复杂的样品前处理操作,而常见的固相萃取技术一般依赖于人工操作,过程复杂且耗时较长,严重影响食品快速检测效率。因此,开发了一种全自动固相萃取装置,通过设计嵌入式硬件电路系统及其软件,精确控制蠕动泵流速和多路阀门开关实现了活化、上样、淋洗、洗脱四个步骤的全自动操作和参数控制,从而达到食品样品的全自动快速固相萃取。在实验部分,配制不同专利蓝V浓度的果汁饮料,然后利用该装置对果汁中的专利蓝V进行前处理,对萃取柱填料和萃取中各个步骤的时间和试剂进行了合理的选择,利用表面增强拉曼光谱检测技术成功地检测了合成色素中的专利蓝V。实验结果表明,所研制的自动固相萃取装置对比传统手工萃取,每个样品节省了近一半的萃取时间（10 min降为5 min）且能够同时处理5个样品,萃取时间稳定不易受人为因素影响,从而极大地提高了萃取效率和稳定性。此外,通过自动萃取获得的样品,对比手工萃取操作,因其受外界干扰相对较小,能够得到更强的拉曼光谱信号（约增强50%）,获得了满意的萃取效果。对不同浓度的专利蓝V样品的结果显示,该方法能够实现检出质量浓度在0.5 mg·L-1水平,可有效满足现场监测需求。具有快速、方便、灵敏度高等特点。国家自然科学基金项目(21874113)资