Nitrogen and phosphorus pollution from urban stormwater runoff in Xiamen City

以厦门岛为研究对象,通过收集代表性样点的降雨径流水样,研究了厦门城市降雨径流中氮、磷浓度及输出特征。结果表明,来源不同的城市降雨径流中氮、磷浓度差异较大,溶解态总氮、硝态氮、氨态氮与总磷的含量分别为1.96~6.77、0.62~4.89、0.35~1.18和0.04~0.66 mg.L-1。降雨过程中氮、磷浓度总体上呈下降趋势,氮浓度波动较大,磷相对稳定。城市降雨径流氮、磷污染受降雨强度、车流量等多种因素影响。城市道路、商住区及工业区径流中氮、磷浓度较高,是城市非点源污染的主要来源,因此对这些区域应重点控制管理。In this study,the stormwater samples of 4 storm events occurred in April and May 2005 were collected from different representative sites including road,roof,and residential,commercial and industrial districts in Xiamen Island.All the samples were delivered to laboratory within 24 h,and their NO_3~——N,NH_4~+-N, dissolved total nitrogen(TN),and total phosphorus(TP) contents were analyzed.The water quality data showed there was a significant difference in the nitrogen and phosphorous concentrations of the stormwater runoff from different sites, with the mean value of TN,NO_3~——N,NH_4~+-N and TP ranged as 1.96-6.77, 0.62-4.89,0.35-1.18 and 0.04-0.66 mg·L~(-1),respectively.In general,the nitrogen and phosphorus concentrations decreased gradually in the process of precipitation due to water dilution,but the nitrogen concentration fluctuated more intensively than phosphorus.Many factors such as precipitation intensity,land cover and vehicle exhaust affected the patterns of nitrogen and phosphorus transportation.The urban stormwater runoff collected from road and commercial and industrial districts contributed a higher nutrient loading,and thus,the management of urban stormwater runoff should be focused on these sites.国家自然科学基金资助项目(40301045)

吉西他滨联合化疗一线治疗晚期胰腺癌生存结果的亚组meta分析

【目的】Meta分析提示吉西他滨（GEM）联合化疗一线治疗晚期胰腺癌优于标准的GEM单药化疗,在此基础上进行亚组生存结果的meta分析及资料更新,旨在寻找确切有效的化疗方案。【方法】通过MEDLINE、EMBASE、ASCO、ECCO等数据库及论文集检索相关文献。按纳入标准筛选新增文献并进行资料更新。主要对各亚组进行半年生存率、其次是1年生存率的meta分析。【结果】17个随机对照临床试验（RCT）共3 821例患者纳入分析,按化疗方案分为GEM联合顺铂（GEMDDP）、GEM固定剂量率输注联合奥沙利铂（GEMOX）、联合5FU（GEMFU）、联合卡培他滨（GEMCAP）以及联合伊立替康（GEMIRI）等5个亚组,各亚组半年生存率的治疗优势（RD）分别为5%（P=0.24）、9%（P=0.005）、2%（P=0.46）、7%（P=0.03）和-1%（P=0.88）;1年生存率RD为6%（P=0.11）、5%（P=0.07）、4%（P=0.19）、5%（P=0.08）和0（P=0.97）。【结论】现有的证据提示GEMOX、GEMCAP联合化疗方案一线治疗晚期胰腺癌,有较好的应用前景,值得进一步的临床试验

一种新的椭球算法

基于更动约束的思想[1 ] 与方法 ,提出了求解线性规划问题的新椭球算法 .它与L .G .Khachian的椭球算法[2 ] 不同 ,在新算法的椭球迭代过程中 ,不仅用约束不等式割掉不含约束集的半个椭球 (椭球中心不在约束集内时 ) ,称之为约束割 ;而且在椭球中心落在约束集内时 ,它用目标不等式割掉含约束集的半个椭球 ,称之为目标割 .新算法的不等式系统是由原规划 (或对偶规划 )的约束不等式与目标不等式组成的 (规模小 ) ,而不是由原椭球算法的K K T条件[5] 组成的不等式系统 (规模大 ) .这种新椭球算法即有多项式计算复杂性的特性 ,又在迭代过程中得到一系列单调趋向最优解的可行解 (在解存在时 ) .如果认为已得满意解 ,可随时停机 .对于实际问题 ,大多数是变量有界的 ,初始椭球不大 ,因此新算法更为实际 ,有效

Ｅｆｆｅｃｔｓ ｏｆ ｅｘｔｅｎｔｅｄ ｈａｒｖｅｓｔ ｔｉｍｅ ｏｎ ｙｉｅｌｄ ｏｆ ｓｐｒｉｎｇ ｍａｉｚｅ ｕｎｄｅｒ

研究延收对春玉米籽粒产量、千粒质量、灌浆速率、光温资源利用及植株器官干物质运移的影响,为玉米延收增产提供依据。【方法】以玉米"金赛6850"为材料,分别设传统耕作、传统耕作+秸秆覆盖、传统耕作+地膜覆盖、免耕+秸秆覆盖、免耕+地膜覆盖5个处理延期收获(习惯收获后,每隔5d为1个收获期),测定在不同耕作覆盖措施下延收对玉米千粒质量和产量的影响。【结果】适时延收,玉米千粒质量和产量增加显著,延收15d,传统耕作千粒质量平均日增3.59g,产量增加1 334.7kg/hm2,灌浆速率为1.7mg/(g.d);延长收获提高了光温资源的有效利用,延收15d,秸秆覆盖和地膜覆盖的有效积温分别增加了180.33和154.98℃,日照时数分别增加53.90和23.30h,植株干物质向籽粒中运移量以传统耕作最多,达10.06g,叶和茎秆的干物质对籽粒增重的贡献率较高。【结论】玉米适时延收具有明显的增产效果,但增产幅度因耕作和覆盖方式不同而有显著差异。 更多还原Ｔｈｅ　ｏｂｊｅｃｔｉｖｅ　ｏｆ　ｔｈｉｓ　ｅｘｐｅｒｉｍｅｎｔ　ｗａｓ　ｔｏ　ｓｔｕｄｙ　ｔｈｅ　ｅｆｆｅｃｔｓ　ｏｆ　ｅｘｔｅｎｄｅｄ　ｈａｒｖｅｓｔｔｉｍｅ　ｏｎ　ｓｐｒｉｎｇ　ｍａｉｚｅ　ｙｉｅｌｄ，１　０００－ｇｒａｉｎ－ｍａｓｓ，ｇｒａｉｎ－ｆｉｌｌｉｎｇ　ｒａｔｅ，ｔｈｅ　ｕｔｉｌｉｚａｔｉｏｎ　ｅｆｆｉｃｉｅｎｃｙ　ｏｆ　ｌｉｇｈｔ　ａｎｄ　ｔｅｍｐｅｒａｔｕｒｅ，ａｎｄ　ｔｈｅ　ｍｉｇｒａｔｉｏｎ　ｏｆ　ｄｒｙ　ｍａｔｔｅｒｓ　ｉｎ　ｔｈｅ　ｐｌａｎｔ　ｏｒｇａｎｓ．Ｔｈｅ　ｒｅｓｕｌｔｓ　ｏｆ　ｔｈｉｓ　ｓｔｕｄｙ　ｗｏｕｌｄ　ｂｅ　ｂｅｎｅｆｉｃｉａｌ　ｔｏｉｎｃｒｅａｓｅ　ｍａｉｚｅ　ｙｉｅｌｄｓ　ｂｙ　ｅｘｔｅｎｄｉｎｇ　ｈａｒｖｅｓｔ　ｔｉｍｅ．【Ｍｅｔｈｏｄ】Ｔｏ　ｄｅｔｅｒｍｉｎｅ　ｔｈｅ　ｅｆｆｅｃｔｓ　ｏｆ　ｅｘｔｅｎｄｅｄ　ｈａｒｖｅｓｔｔｉｍｅ　ｏｎ　１　０００－ｇｒａｉｎ－ｍａｓｓ　ａｎｄ　ｙｉｅｌｄ　ｏｆ　ｇｒａｉｎ　ｕｎｄｅｒ　ｄｉｆｆｅｒｅｎｔ　ｃｕｌｔｉｖａｔｉｏｎ　ａｎｄ　ｍｕｌｃｈｉｎｇ　ｍｅａｓｕｒｅｓ，ｆｉｖｅ　ｌｅｖｅｌｓ　ｏｆＣＴ，ＣＳ，ＣＰ，ＮＴＳ　ａｎｄ　ＮＴＰ　ｗｅｒｅ　ｓｅｔ　ａｓ　ｅｘｔｅｎｔｅｄ　ｈａｒｖｅｓｔ　ｔｉｍｅ．“Ｊｉｎｓａｉ　６８５０”ｗａｓ　ｕｓｅｄ　ａｓ　ｔｈｅ　ｔｅｓｔｅｄ　ｓｐｅｃｉｅｓ，ｗｈｉｃｈ　ｗａｓ　ｈａｒｖｅｓｔｅｄ　ｏｎｃｅ　ｅｖｅｒｙ　５ｄａｙｓ　ａｆｔｅｒ　ｕｓｕａｌ　ｈａｒｖｅｓｔ　ｔｉｍｅ．【Ｒｅｓｕｌｔ】Ｅｘｔｅｎｄｅｄ　ｈａｒｖｅｓｔ　ｔｉｍｅ　ｓｉｇｎｉｆｉｃａｎｔｌｙ　ｉｎｃｒｅａｓｅｄ　ｍａｉｚｅ　ｙｉｅｌｄ　ａｎｄ　１　０００－ｇｒａｉｎ－ｍａｓｓ．Ｗｉｔｈ　ａｎ　ｅｘｔｅｎｓｉｏｎ　ｏｆ　ｔｈｅ　ｈａｒｖｅｓｔ　ｂｙ　１５ｄａｙｓ，ｔｈｅ　ａｖｅｒａｇｅ１　０００－ｇｒａｉｎ－ｍａｓｓ　ｕｎｄｅｒ　ｃｏｎｖｅｎｔｉｏｎａｌ　ｔｉｌｌａｇｅ　ｉｎｃｒｅａｓｅｄ　ｂｙ　３．５９ｇ　ｐｅｒ　ｄａｙ．Ｇｒａｉｎ－ｆｉｌｌｉｎｇ　ｒａｔｅ　ｗａｓ　１．７ｍｇ／（ｇ·ｄ）．Ｔｈｅ　ａｃｃｕｍｕｌａｔｅｄ　ｔｅｍｐｅｒａｔｕｒｅ　ｈｉｇｈｅｒ　ｔｈａｎ　１０℃ｕｎｄｅｒ　ｓｔｒａｗ　ｍｕｌｃｈｉｎｇ　ａｎｄ　ｐｌａｓｔｉｃ　ｆｉｌｍ　ｗａｓ　ｉｎｃｒｅａｓｅｄ　ｂｙ１８０．３３ａｎｄ　１５４．９８℃，ｒｅｓｐｅｃｔｉｖｅｌｙ，ａｎｄ　ｓｕｎｓｈｉｎｅ　ｄｕｒａｔｉｏｎ　ｗａｓ　ｉｎｃｒｅａｓｅｄ　ｂｙ　５３．９０ａｎｄ　２３．３０ｈａｓ　ｗｅｌｌ．Ｔｈｅｍａｘｉｍｕｍ　ｍｉｇｒａｔｉｏｎ　ｏｆ　ｄｒｙ　ｍａｔｔｅｒ，ｗｈｉｃｈ　ｍａｉｎｌｙ　ｃａｍｅ　ｆｒｏｍ　ｔｈｅ　ｌｅａｆ　ａｎｄ　ｓｔｅｍ，ｗａｓ　１０．０６ｇ　ｕｎｄｅｒ　ｔｈｅ　ｃｏｎｖｅｎｔｉｏｎａｌ　ｔｉｌｌａｇｅ．【Ｃｏｎｃｌｕｓｉｏｎ】Ｅｘｔｅｎｄｅｄ　ｈａｒｖｅｓｔ　ｔｉｍｅ　ｓｉｇｎｉｆｉｃａｎｔｌｙ　ｉｎｃｒｅａｓｅｄ　ｓｐｒｉｎｇ　ｍａｉｚｅ　ｙｉｅｌｄ，ａｎｄ　ｔｈｅ　ａｍｏｕｎｔ　ｏｆ　ｉｎｃｒｅａｓｅ　ｗａｓ　ｈｉｇｈｌｙ　ｒｅｌａｔｅｄ　ｔｏ　ｄｉｆｆｅｒｅｎｔ　ｔｉｌｌａｇｅ　ａｎｄ　ｃｏｖｅｒａｇｅ　ｍｅａｓｕｒｅｓ

HPON突发模式AOWC的输入范围扩展方法

文章提出一种基于全光波长转换（AOWC）的新型波分/时分混合复用无源光网络（HPON）架构,使用掺铒光纤放大器（EDFA）来扩展突发模式全光波长转换模块（BM-AOWCM）的输入动态范围,以满足系统上行2.5 Gbit/s突发信号波长转换应用的要求。分析了动态范围扩展的原理,并通过仿真进行验证。搭建了测试系统,实验结果表明,在误码率为10-9时,动态范围可以由5.5 dB扩展到29.8 dB

Shock calibration of piezoresistive high-g_n microaccelerometer

采用体硅微机械加工技术和扩散技术，制作压阻式高量程微加速度计，设计量程为50000 g_n。芯片材料为单晶硅，采用双列扁平陶瓷封装。为了测量其动态灵敏度，使用Hopkinson杆在约40000 g_n的加速度水平下进行了冲击校准。在电桥电压为6.33V的情况下，被测微加速度计的灵敏度为1.26 μV/g_n

Solid Superacid SO~(2-)_4/Fe_2O_3 Catalyzed Esterification of N,N-Diethylaminoethanol with Aromatic Carboxylic Acids

用固体超强酸SO2-4/Fe2O3催化N,N 二乙氨基乙醇与9个含芳香环羧酸的酯化反应,合成了9个相应的酯,产率在75%～95.6%之间.讨论了不同的固体超强酸及催化剂用量,溶剂和反应温度,反应时间等因素对酯化产率的影响.实验结果表明:当催化剂用量占反应物总量的3.4%～3.8%,溶剂为二甲苯,反应温度140℃,反应时间6h的条件下,酯化产率最高.N,N-Dialkylaminoethyl esters have been found to possess a range of interesting biological activities. Reported methods in the literature have one or more drawbacks such as the use of harsh reaction conditions and environmental unfriendly reagents required more than one reaction steps and, in some cases, giving low yields of the products. Therefore more efficient methods for the preparation of this type of compounds remain to be developed. In this paper we report an environmentally friend and efficient one step synthesis of N, N-diethylaminoethyl esters. Under optimized conditions, nine N, N -diethylaminoethyl aromatic esters have been synthesized using solid superacid Fe_2O_3/SO~(2-)_4 as catalyst with yields ranging from 75% to 95.6%. Factors which affect the esterification such as types of solid superacids, solvents, reaction temperature, reaction time and amounts of catalyst were studied.This method has advantages over the traditional ones in that: it requires only catalytic amount of catalyst and the work-up procedure is simple; it does not form amine salt as protonic acid condensation agents do; it produces no acidic waste and is less corrosive to the reaction vessels than other conventional condensation agents. This method is expected to have potenteal application in the preparation of other diethylaminoethyl esters and in general ester synthesis