角膜塑形镜控制青少年低中高度近视发展的效果

【目的】探讨过夜配戴角膜塑形镜（OK镜）治疗青少年轻度、中度及高度近视的效果差异。【方法】前瞻性病 例研究。收集 54 例（107 眼）青少年近视患者，平均年龄（11.6 ± 2.4）岁，按患者戴镜前等效球镜度分为低度近视组（51 眼，-0.75 ~ -3.00 D）、中度近视组（36眼，-3.25 ~ -5.00 D）及高度近视组（20眼，-5.25 ~ -9.00 D）。观察配戴前1天及配戴1 年后3组内及组间等效球镜度、中央角膜厚度、角膜曲率、前房深度和眼轴变化。【结果】轻度近视组、中度近视组及高度近 视组基线平均等效球镜度（D）分别为-2.15 ± 0.63、-4.20 ± 0.54 和-6.63 ± 1.18；三组基线眼轴（mm）分别为 24.50 ± 0.66、 25.16 ± 0.65及26.35 ± 0.87。三组患者基线中央角膜厚度、前房深度、中央角膜K值、平K值及陡K值差异均无统计学意 义。戴镜1年后3组眼轴增长值（mm）分别为0.22 ± 0.27、0.09 ± 0.22和0.02 ± 0.22；其中低度近视组与中度近视组、高度近 视组相比，组间眼轴增长值差异有统计学意义（P值分别为0.04、0.008），中度近视组与高度近视组两组间眼轴增长值差异 无统计学意义（P值为0.35）。三组戴镜1年后等效球镜度显著下降，3组内差异均有统计学差异（P均< 0.0001），低度近视组 与中度、高度近视组间差异具有统计学意义（P均< 0.0001）。1年前后3组中央角膜K值、平K值、陡K值均明显变平坦，组 内差异比较均有统计学差异（P均< 0.0001）。中央角膜厚度、前房深度及角膜直径1年前后差异无统计学意义。【结论】中 高度近视者采用角膜塑形镜控制近视的作用较低度近视更优。角膜曲率改变的量可能是影响OK镜近视治疗效果的主要 因素之一

Investigation of the origin and evolution of groundwater in Yang-Dai River Plain by chlorine,oxygen 18 and deuterium

通过分析地表水和地下水中氯离子浓度和δd、δ18O值的空间分布特征,揭示了秦皇岛洋戴河平原地下水的形成演化规律.结果发现,洋戴河平原地表河水来源于中上游水库水和大气降水的混合,且河水沿程受到δd、δ18O值、氯离子浓度更低的支流或灌渠水补给,从而使δd、δ18O值、氯离子浓度呈现沿程逐渐降低的现象.山前丘陵区地下水主要接受大气降水的直接补给,洪积扇及山麓地带地下水受到了一定的蒸发作用影响,除了接受丘陵区地下水的侧向补给外,洋河附近地下水还受到洋河水库水的混合.研究区西部咸水带的地下水由上游地下水和大泥河地热咸水混合而成,地热咸水的混合比率约为13%,而东部咸水带的地下水由上游地下水、本地污水和地热咸水混合而成,地热咸水的混合比率不超过9%.在海水入侵区,地下水主要由本区地下淡水和海水(海水混合比率不超过10%)混合而成,并且受到了不同程度的地表水或农田灌溉水的补给,其中,浦河一带是地表水或灌溉水补给较为明显的地段.The aim of this paper is to reveal the origin and evolution of surface water and groundwater by analyzing the spatial distribution of chloride ion concentration and δD and δ18O values in surface water and groundwater in Yang-Dai River Plain.The Yang-Dai River originates from the mixing of water of reservoir and meteoric water,and river water is also from the recharge in the tributary and irrigation ditch which have much lower chloride ion concentration and δD and δ18O values.Therefore,chloride ion concentration and δD and δ18O values in river water decreases gradually from upstream to downstream.The groundwater in hilly area is primarily recharged by meteoric water,and the groundwater in pluvial fan and piedmont experiences evaporation partly.The groundwater in pluvial fan and piedmont is recharged not only laterally by upstream groundwater from mountainous and hilly area,but also by Yang River reservoir water.In the study area,the groundwater in the west part of salty water region is mixed between upstream groundwater and salty geothermal water originated from Danihe area,with a mixing radio of 13% salty geothermal water.In comparison,the groundwater in the east part of salty water region is mixed by upstream groundwater,sewage water and salty geothermal water,with a mixing radio of up to 9% salty geothermal water.In the seawater intrusion region,the groundwater was mainly constituted of local fresh groundwater and intrusive seawater with a mixing ratio of up to 10% seawater,and is also partly recharged by surface water and agricultural irrigation water which have higher contribution to the groundwater recharge in Pu River area.国家重点基础研究发展计划(973)项目(No.2010CB428805); 环保公益性行业科研专项经费项目(No.201309006)~

Imposex of Thais clavigera and Cantharus cecillei in the coastal waters of Xiamen

海产腹足类性畸变以其对有机锡的敏感性、特异性和不可逆性而成为海洋有机锡污染的理想指示种。调查研究了厦门海域岩相海岸带疣荔枝螺(THAIS ClAVIgErA)和甲虫螺(CAnTHAruS CECIllEI)的性畸变情况,通过生物学指标IOI(性畸变率)、rPSI(相对阴茎发展指数)、VdSI(输精管发展指数)及SrI(性比指数)综合评价其性畸变发展程度,间接指示厦门周边海域的有机锡污染程度。研究结果发现,在采集疣荔枝螺的17个站点中有5个站点种群性畸变率为100%,其中宝珠屿种群性畸变程度最为严重,VdSI达4,采集甲虫螺的4个站点的种群性畸变率均为100%。性畸变程度较严重的种群普遍集中于厦门西港,并且表现出由港内到港外逐渐减轻的趋势,而白城、会展中心和大嶝岛等位于开阔的厦门东海域的种群性畸变程度最轻,与往年厦门西海域有机锡污染监测数据相比一致,体现出性畸变程度与有机锡污染程度及海港码头远近之间的相互关系。The degree of imposex,i.e.the imposition of male characteristics onto females,in neogastropods can be used as a sensitive and accurate biomarker to evaluate organotin contamination in coastal marine environment.Now,the imposex status in females of Thais clavigera and Cantharus cecillei in 17 sites was investigated to evaluate the organotin contamination along Xiamen Bay during 2006 and 2007.The four indices including incidence of imposex(IOI),relative penis size index(RPSI),vas deferens sequences index(VDSI) and sex ratio index(SRI) were used comprehensively to assess the imposex status in order to ascertain the extent of organotin bioavailability in Xiamen Bay.Based on this research,T.clavigera in 5 sites and C.cecillei in all survey sites exhibited the IOI of 100%.At Bao ZhuYu Islet,the imposex level was the most serious with maximum VDSI value of 4.In general,the imposex level decreased from the inner to the outer of Xiamen Western Harbour,and the populations in the open Xiamen Eastern Waters including Bai Cheng,Convention and Exhibiton Center and Dadeng Island showed a lower imposex level.These results were accordant with the concentrations of organotins in 2005.The imposex degree also increased with increasing organotin contamination and decreasing distance from shipping facilities.国家自然科学基金资助项目(40476048);厦门大学近海海洋环境科学国家重点实验室开放基金资助项目;厦门大学新世纪优秀人才计划基金资助项

Design of Robotic Visual Servo Controll Based on Neural Network

视觉伺服可以应用于机器人初始定位自动导引、自动避障、轨线跟踪和运动目标跟踪等控制系统中。传统的视觉伺服系统在运行时包括工作空间定位和动力学逆运算两个过程,需要实时计算视觉雅可比矩阵和机器人逆雅可比矩阵,计算量大,系统结构复杂。本文分析了基于图像的机器人视觉伺服的基本原理,使用BP神经网络来确定达到指定位姿所需要的关节角度,将视觉信息直接融入伺服过程,在保证伺服精度的情况下大大简化了控制算法。文中针对Puma560工业机器人的模型进行了仿真实验,结果验证了该方法的有效性

Chemical Constituents from Przewalskia tangutica

目的:对马尿泡全草化学成分进行研究。方法:采用各种色谱技术分离纯化马尿泡全草醇提物正丁醇部位的化学成分,并运用波谱技术进行结构鉴定。结果:从马尿泡正丁醇部位分离鉴定了12个化合物,分别为:东莨菪苷(1)、法荜枝苷(2)、芦丁(3)、queroetin-3-O-rutinoside-7-O-β-D-glucopyranoside(4)、原儿茶酸(5)、香草酸(6)、胸腺嘧啶(7)、尿嘧啶(8)、胞嘧啶(9)、腺嘌呤(10)、尿嘧啶核苷(11)、腺嘌呤核苷(12)。结论:其中,化合物3~5、8~12为首次从该植物中分离得到

Design of H-infinity feedback controller and IP-position controller of PMSM servo system

Using H&infin; control theory to design feedback controller can enhance the anti-disturbance capability and servo precision of AC permanent magnetic servo motor. Consequently, the system robustness can be ensured even with the existence of model perturbations and external disturbance. H&infin; feedback controller design using robust control theory can be a guarantee of system robustness when the control object is subject to model perturbations and external disturbances. Compared with traditional PI-controller, IP-controller can increase response speed and meet the desired position of the system more accurately. Both the H&infin; feedback controller design to elevate the operation precision and the design approach for IP-controller is discussed in this paper

Seawater Intrusion Degree Evaluation Based on Mathematical Statistics and Fuzzy Mathematics in Qinhuangdao Yangdai River Plain

运用数理统计方法获取秦皇岛洋戴河平原地下潜水和海水的水化学统计特征,据此优选出4项海水入侵评判指标,建立各评判指标的背景值及指标等级体系,并将模糊数学综合评价法和地理信息系统结合起来评价研究区潜水含水层的海水入侵程度。研究结果表明:氯离子Cl-、电导率EC、溶解总固体TdS和潜在盐度是指示本区潜水含水层海水入侵程度的最佳指标,其判别海水入侵发生的下限值分别为250 Mg/l、1 250μS/CM、700Mg/l和8.5 MEQ/l;洋戴河平原潜水含水层的海水入侵程度总体上为中等水平,洋、戴河间浦河一带的潜水含水层海水入侵程度最为强烈。Analyzing the distribution map of seawater intrusion degree can increase the knowledge of seawater intrusion mechanism,which is not only the important reference for water supplies of production and daily life but also the core content of seawater intrusion survey and research.In this article,four effective indicators for seawater intrusion of Qinhuangdao Yangdai River Plain which is located in the northeast of Hebei Province were selected out according to the different hydrochemical characteristics of fresh groundwater,brackish groundwater and seawater using the method of mathematical statistics.And then,the background values and index system of those seawater intrusion indicators were built to carry on seawater intrusion degree evaluation work based on the approach of fuzzy synthetic evaluation and geographic information system.The research results can be showed as follows: The chloride ion(Cl-),electric conductivity(EC),total dissolved solids(TDS) and potential salinity are the optimal seawater intrusion indicators which can help to distinguish the intruded samples from all groundwater samples.The background value of study area for chloride ion concentration,EC,TDS and potential salinity are 83.06-243.8 mg/L,600-1 222 μs/cm,341.82-679.14 mg/L and 2.92-8.05 meq/L,respectively.The lower limit value of chloride ion concentration,EC,TDS and potential salinity are 250 mg/L,1 250 μs/cm、700 mg/L and 8.5 meq/L,respectively,which can manifest the occurrence of seawater intrusion.The groundwater samples identified seawater intrusion degree as rank II and rank III,make up 74% of all samples,which reveals that seawater intrusion degree of study area generally belongs to the medium level.On the basis of the distribution map of seawater intrusion degree,the seawater intrusion degree of the alluvial aquifers around Pu River between the Yang River and Dai River is the highest.国家重点基础研究发展计划(973)项目(2010CB428805)资