Distributions of dissolved organochlorine pesticides and polychlorinated biphenyls in China coastal waters

分析调查了中国部分海域海水中溶解态有机氯农药(OCPS,25种)和多氯联苯(PCbS,6种)的残留分布特征。结果表明,所有采样点都不同程度地受到了OCPS和PCbS的污染,其中福建省福州平潭和莆田湄洲岛的OCPS污染较为严重,浓度分别达到1752.59和796.19 ng/l;而辽宁省的大连老虎滩OCPS污染较轻,浓度为53.63 ng/l。各采样点海域海水中HCHS污染程度一般高于ddTS,HCHS主要以早期残留为主;根据ddT/ddTS的比值推测,在福州平潭、莆田湄洲岛和珠海淇澳岛水体显示有新的ddT输入。在各海域水体中溶解态PCbS的浓度为33.55--474.92 ng/l,均超过了美国环保局规定的海水浓度限值。因此目前我国沿海海域水体中持久性有机污染物有机氯农药和多氯联苯污染仍不能忽视。The concentrations of organochlorine pesticides(OCPs,25) and polychlorinated biphenyls(PCBs,6) in seawater collected from China coast were investigated.The results showed that concentrations of OCPs ranged from 53.63 to 1752.59 ng/L in seawater,and the highest value was in Pingtan(Fuzhou) while the lowest value was in Laohutan(Dalian,Liaoling province).At all of sampling sites,the concentrations of DDTs and HCHs were lower than the limits of national seawater quality standards(class 1),and the concentration of HCHs was higher than that of DDTs.The ratios of DDT/DDTs showed new DDT into Pingtan(Fuzhou),Meizhoudao(Putian) and Qi'aodao(Zhuhai,Guangdong Province),whereas the isomers characteristics for HCHs showed the residues at all sampling sites.The concentrations of dissolved PCBs ranged from 33.55 to 474.92 ng/L in seawater,which were higher than the limit of EPA seawater quality standard.However,the occurrence of OCPs and PCBs in seawater along China coast should be concerned.国家自然科学基金(40476048;20777060);厦门大学新世纪优秀人才计划基

连续输出1.60W/473nm直腔蓝光激光器

报道了LD端面泵浦Nd∶YAG晶体,LBO腔内倍频473 nm全固态直腔蓝光激光器.根据谐振腔稳定性理论,利用简单的平-平腔直接测得不同泵浦功率下的热焦距值.通过数值计算分析了不同热焦距下,Nd∶YAG与LBO晶体中的腰斑半径以及LBO中光腰的位置,并在准三能级系统模型和倍频理论的指导下优化激光腔体结构,使激光器实现最佳的模式匹配和倍频效率,得到高效的蓝光激光输出.激光阈值为1.92 W;当泵浦激光功率为20.58 W时,473 nm蓝光的输出功率为1.60 W,光-光转化效率为7.8%

COCCOSPHERE RELIEVES THE STRESS OF ULTRAVIOLET RADIATION ON PHOTOSYNTHESIS IN THE COCCOLITHOPHORID EMILIANIA HUXLEYI

颗石藻(Coccolithophore)是一类胞外具有数层钙质颗石粒(Coccolith)的海洋钙化金藻,在绝大部分海域均有分布。颗石藻通过光合固碳向深海沉降有机碳颗粒,同时其钙化作用形成的颗石粒是海底的重要沉积物。它们与钙化浮游动物翼足类(Petropod)钙化量可占海洋生物钙化量的80%,对于海洋碳、钙循环有重要意义~([1,2])。颗石藻在条件合适时,可形成大面积藻华(全球每年可达上百万平方公里)~([3])。促进藻华形成的环境因素很汕头大学青年基金(YR13002);; 近海海洋环境科学国家重点实验室(厦门大学)访问学者与开放课题(MELRS1305);; 广东省大学生创新创业训练计划项目(201510560079);; 国家自然科学基金(31370476);; 广东省海洋渔业科技与产业发展专项(A201401D03);; 广东省科技计划项目(2014A020217005);; 广东省产学研项目(2012B091100341)资助~

端面泵浦Nd∶YAG连续输出1052nm波长激光器

设计了一个简单紧凑的1052nm波长激光器。首次利用激光二极管(LD)端面泵浦Nd∶YAG晶体,使用镀有高度选择性介质膜的反射镜产生该波段的激光。激光阈值为0.3W,当808nm波长泵浦光功率达到18W时产生了3.5W的1052nm波长激光输出。光-光转换效率为20%,输出激光功率波动不超过3%

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

基于翻转课堂的信号与系统课程教学模式改革

分析信号与系统课程传统教学模式存在的问题,以及微课和翻转课堂的优点,从课前学习、课堂讨论、课后巩固和评价考核方式四个方面设计基于翻转课堂的新的教学模式。以零输入响应和零状态响应为案例,详细说明基于翻转课堂的教学设计。实践表明,新的教学模式能充分调动学生学习的主动性和积极性,改善教学效果。广西高等教育本科教学改革工程项目(2016JGA180)； 广西民族大学混合式课程立项项目； 广西教育厅首批在线开放课程建设与应用立项项

Adaptive Power Control Strategy Based on Spectrum Sensing for Cognitive Relay Networks

针对采用联合overlay和underlay频谱共享模式的认知中继网络,基于频谱感知结果和干扰信道条件,提出了自适应功率控制策略,从理论上分析了次用户的中断概率。通过Monte-Carlo仿真,与单一overlay或underlay频谱共享模式和固定功率控制方案下次用户的中断性能进行了比较。仿真结果表明,采用自适应功率控制方案,在相同中断概率条件下,次用户对主用户的干扰概率降低了70%~80%;在相同干扰概率条件下,次用户的中断概率降低了1~2个数量级,频谱共享性能得到了有效提高。An adaptive power control scheme is proposed for the cognitive relay networks with joint overlay and underlay spectrum sharing model. The transmit power of the secondary user is adjusted adaptively ac-cording to the spectrum sensing results and the interference channel condition. The outage probability of the secondary user is compared by Monte-Carlo simulations between the fixed power control scheme and pure overlay or underlay spectrum sharing schemes. The results show that,by employing the adaptive power control strategy,the interference probability of the secondary user to the primary user is decreased by 70% ？80% under the same outage probability. Also, the outage probability of the secondary user is re-duced by 1 ？ 2 orders of magnitude under the same interference probability. Thus, the performance of the spectrum sharing is improved effectively.国家自然科学基金资助项目(61362010)； 广西自然科学基金资助项目(2016GXNSFAA380091)； 广西高等学校科学研究资助项目(2013YB073)； 广西高校复杂系统与智能计算开放课题(2016CSCI08

同分布Rayleigh衰落信道下认知中继网络中断概率精确解

研究了underlay频谱共享模式下认知中继网络的中断性能,推导出独立非同分布Rayleigh衰落信道下次用户中断概率精确解的闭合表达式。通过对具有不同分布参数的Rayleigh衰落信道下系统性能进行MonteCarlo仿真,验证了理论推导的正确性。仿真结果表明,次用户发射机与中继之间(S_T→S_R)的中继链路以及次用户发射机与主用户接收机之间(ST→PD)的干扰链路——这两种链路的信道状态是影响认知中继网络中断性能的主要因素。国家自然科学基金资助项目(61362010);广西自然科学基金资助项目(2012GXNSFBA053162);广西高等学校科学研究资助项目(2013YB073);广西民族大学引进人才资助项目(2012QD018

Experiment Teaching Reform on Communication Principlebased on Micro-lecture and MATLAB

分析采用实验箱开设通信原理实验的不足,提出应用微课和MATLAB进行通信原理实验教学的优点。以QPSK调制与解调实验为例,详细说明基于微课和MATLAB的实验教学设计与实现思路。结果表明,利用微课和MATLAB能有效增强通信原理实验教学的效果,有助于学生对理论知识的理解。 In this paper, the short points of the experiments for communicationprinciple on the experiment case are analyzed, and thenthe advantages of applying the micro-lecture and MATLAB intothe teaching of the communication principle experiment are putforward. Taking the modulation and demodulation of QPSK signalfor example, the teaching design and realization based on microlectureand MATLAB are described in detailed. The results showthat the experiment teaching eff ect can be prompted greatly and thestudents can benefi t from the teaching reform.2016年广西高等教育教学改革工程项目(2016JGA180);2013年广西民族大学教育教学改革工程项目;2015年广西高校青年教师教学业务能力提升计划项目(第二期

Multiple phases tracking and compensation for LOS MIMO systems

针对LOS MIMO系统中分布式天线的多个发送端相位噪声和多个接收端相位噪声,基于LMS准则和线性均衡提出了多相位跟踪与补偿算法,通过仿真分析了该算法在不同的振荡器配置、相位噪声带宽、调制阶数和迭代步长下系统的误符号率性能。并与基于锁相环的多相位跟踪算法(PLL)作比较,结果表明:LMS算法的误符号率性能明显优于PLL算法,能有效降低LOS MIMO系统的误符号率,且更具有实用性。Aiming at the multiple phase noises in distributed transmitter and receiver antennas of LOS MIMO systems,a tracking and compensation algorithm for multiple phases based on LMS criterion and linear equalization is proposed.The symbol error rate（SER） performance is analyzed by simulations under various oscillator configurations,phase noise bandwidth,modulation orders and step sizes.Then,compared with the existed algorithm based on phase-locked loop（PLL）,the simulation results show that the SER performance of the LMS algorithm is superior to the PLL algorithm.The proposed LMS algorithm can reduce the SER of LOS MIMO systems more efficiently,thus is more practicable than the PLL algorithm.国家自然科学基金(61362010)； 广西自然科学基金(2016GXNSFAA380091)； 广西高等学校科学研究项目(2013YB073