浊点萃取预富集-火焰原子吸收光谱法测定环境水中钴

以浊点萃取为分离富集方法,以火焰原子吸收光谱法为检测手段,探讨了测定钴的新方法.以非离子型表面活性剂OP-8为萃取剂,同时以1-(2-吡啶偶氮)-2-萘酚为络合剂,浊点萃取水样中的痕量钴(Ⅱ).对溶液pH值、试剂浓度、平衡温度和时间、离心时间等实验条件进行了优化.钴的质量浓度在1.00 mg/L以内与其吸光度呈线性关系,检出限(3σ)为0.26,μg/L,相对标准偏差为2.5％(p=0.4 mg/L,n=5次).该法用于自来水、河水、湖水以及雨水中痕量钴的测定,回收率在96.0％～103.0％,结果令人满意.     

太阳能1.x级溴化锂吸收式制冷循环性能分析

介绍了一种适合于太阳能和其他低温热源利用的新型1.x级溴化锂吸收式制冷循环.通过编制计算机程序模拟计算表明:循环热力系数和面积单耗都随循环中间压力升高而增大,且达到一定数值时循环将不能继续;冷却水先进入冷凝器的串联流程优于并联流程;随着热水或冷媒水温度的降低或冷却水温度的升高,溴冷机循环系统的热力系数、面积单耗等经济性指标都变差,但在现有太阳能集热器能提供的热水温度范围内,1.x级循环的性能指标明显高于两级循环.     

浊点萃取-火焰原子吸收光谱法测定水样中痕量铅的研究

提出了浊点萃取-火焰原子吸收光谱法测定痕量铅的新方法,并详细探讨了溶液pH值、试剂浓度等实验条件对浊点萃取及测定灵敏度的影响.在最佳条件下,富集50 mL样品溶液,用火焰原子吸收光谱法测定,铅的检测限为0.82μg/L,铅的富集倍数为66倍.该方法可用于自来水、井水及河水中痕量铅的测定.     

一种新的太阳能吸收式制冷系统中的蓄能技术

提出了一种可用于太阳能吸收式制冷系统中的新型蓄能循环,利用储存的浓度势差,实现全天候制冷。分析了它的性能特性,并与传统的蓄热方式和蓄冷方式的蓄能系统进行分析比较,结果表明,在获得冷量相同情况下,新型循环的蓄能体积是传统系统蓄能体积的0.2以下,1m^3蓄能体积的冷量能维持50－60m^2房间的夜间冷量,促进蓄能装置小型化 ,从而推动小型太阳能吸收式蓄能空调的商品化。     

Analyzing global trends of different cloud types and their potential impacts on climate by using the ISCCP D2 dataset

The International Satellite Cloud Climatology roject (ISCCP) D2 dataset is used to study the global distribution of low, middle and high cloud amounts and their rends of 1983-2001. Evidences have shown that global arming has accelerated over the past 20 a and the 1990s as the warmest decade in the instrumental records since 861. Trends of various clouds amounts over this period are nalyzed by employing the linear regression method. The esults show that global mean total cloud amounts, in general,have tended to reduce over the past 20 a. But there are lightly increasing by about 2% before 1987 and decreasing y about 4% since then. Cloudiness trends of both low and igh clouds decrease while increase for the middle cloud.And there exist remarkable discrepancies in different regions.The preliminary analyses suggest that it is likely that the loud change occurring over the past 20 a is a positive feedback to global warming.     

Multi-scale pressure-balanced structures in the solar wind observed by WIND

This work detects multi-scale, from hour to seconds, pressure-balanced structures (PBSs) in the solar wind based on the anti- correlation between the plasma thermal pressure and the magnetic pressure measured by WIND at 1 AU on April 5th, 2001. In our former research based on Cluster measurements, we showed the anti-correlation between the electron density and the magnetic field strength in multi-scales, and we supposed these structures may be pressure-balanced structures. Thus, in this work we aim to prove our speculation by the direct evidence on pressure measurements. Different from our previous work, we apply the WIND measurements this time, for they have both the magnetic pressure and the plasma pressure which Cluster could not offer. We use the wavelet cross-coherence method to analyze the correlation between the plasma pressure (P th ) and the magnetic pressure (P B ), and also the electron density (N e ) and the magnetic field strength (B) on various scales. We observe the anti-correlation between P th and P B distributed at different temporal scales ranging from 1000 s down to 10 s. This result directly indicates the existence of pressure- balanced structures (PBSs) with different sizes in the solar wind. Further, We compare the wavelet cross correlation spectrum of P th -P B and N e -B. We notice that the two spectra are similar in general. Thus this result confirms that the relation between P th -P B and N e -B are consistent with each other in the PBSs we study. Moreover, we compare the power spectrum density (PSD) of relative N e fluctuation with our previous work based on Cluster measurements. The two spectra show similar trend with Komolgorov’s -5/3 as their slopes. This may imply the similarity of the structures observed by both WIND and Cluster spacecrafts. Finally, we discuss the possible formation mechanisms for these multi-scale pressure-balanced structures. Our result is important to support the existence of multi-scale PBSs from one-hour scale down to one-minute, and is helpful to understand the role of compressive fluctuation in the solar wind turbulence dominated by Alfvénic cascading.     

用原子吸收光谱法测定催化剂中的铂

建立了利用石墨炉原子吸收光谱法测定催化剂中铂含量的方法。在标准溶液和试样溶液中加入铜离子,可以消除其他离子的干扰,并且提高测定铂的灵敏度。实验表明,高浓度的铝对测定结果有影响,而酸度的影响很小。在一定的浓度下,Fe3+,Ni2+等7种干扰离子对测定结果的影响很小。该方法的检出限为0.044mg/L,加标回收率为99%～105%,相对标准偏差在0.73%左右。     

用原子吸收光谱法测定催化剂中的铂

建立了利用石墨炉原子吸收光谱法测定催化剂中铂含量的方法。在标准溶液和试样溶液中加入铜离子，可以消除其他离子的干扰，并且提高测定铂的灵敏度。实验表明，高浓度的铝对测定结果有影响，而酸度的影响很小。在一定的浓度下，Fe^3 ，Ni^2 等7种干扰离子对测定结果的影响很小。该方法的检出限为0．044mg／L，加标回收率为99％～105％，相对标准偏差在0．73％左右。     

灰飞虱共生菌Wolbachia引起的细胞质不亲和性

对我国６个地区和日本３个地区灰飞虱的Ｗｏｌｂａｈｉａ感染率，用ＰＣＲ技术进行了检测，结果表明中国的辽宁、北京、上海和云南的灰飞虱的Ｗｏｌｂａｃｈｉａ感染率均接近１００％；四川为５９．６％；而宁夏为０。各地区灰飞虱间的交配实验证明了在Ｗｏｌｂａｃｈｉａ引起的细胞质不亲和现象的存在，Ｗｏｌｂａｃｈｉａ１６ＳｒＤＮＡ的部分测序分析表明，上海、云南和日本出云的灰飞虱发的同为Ｗｏｌｂａｃｈｉａ ｐｉｐｉｅｎ     

原子吸收分光光度法测定岩石矿物中锑的研究

用空气-乙炔火焰原子吸收分光光度法,在10%HCl介质中测定矿石中的锑.方法具有简单、快捷、准确、节省试剂等优点.方法检出限为0.05μg/mL,准确度为2.3%,精密度为1.3%,线性范围为1.0～20.0/mL.本法适用于辉锑矿、铜精矿、铅精矿、锌精矿等矿石中0.03%～5.0%锑的测定,而锑的边界品位是0.5%～0.7%,所以该方法完全满足岩石矿物中锑的测定.     

菌根真菌对有机氮吸收利用的研究进展

综述了菌根真菌对有机氮的吸收利用在植物生理学、分子水平及实验装置方面国内外近年来取得的一些研究成果.菌根真菌吸收有机氮后能向宿主植物转运,其中丛枝菌根真菌吸收氨基氮后在根外菌丝中合成载体———精氨酸(Arg),它既能在根外菌丝(ERM)和根内菌丝(IRM)间双向运转,又能在根内菌丝中经尿素循环分解成NH4+,作为氮源整合入根内菌丝中的其他氨基酸或通过NH4+-转运蛋白转运给宿主植物.已经从菌根真菌中克隆出或检测到表达一些与氮代谢相关的基因.与研究需求相适应的实验装置也在不断发展.     

石墨炉原子吸收分光光度法测定豆制品中铝含量

采用Z-8000型偏振塞曼原子吸收分光光度计对不同加工方法的铝含量进行了测定研究,结果表明:大豆及豆制品中Al含量一般均低,但个别豆制品中Al含量偏高,尤其是油炸品,应引起重视.     

原子吸收分光光度法测定草珊瑚中微量铁的含量

目的 以原子吸收分光光度法为基础建立测定草珊瑚中微量铁的新方法.方法 用浓度为3.0 μg/mL的铁测试液于2%HCl溶液的体系中,研究吸收波长、燃烧器高度、灯电流(ILamp)大小、狭缝宽度(d)、空气和乙炔的流量比对测试结果的影响.最佳的测试条件为:吸收波长为248.3 nm,燃烧器高度为6.0 mm,ILamp为2.0 mA,狭缝宽度为0.1 nm,乙炔、空气流量比为1.7/6.2.结果 在最佳实验条件下,铁含量在0.0～5.0μg/mL范围内与吸光度A之间呈线性关系,即A=0.078ρFe+0.008,其中ρFe为铁标准溶液浓度(μg/mL),此方程线性相关系数r=0.999 0,所建立方法的相对标准偏差为0.09%～1.15%,相对误差小于1.5%.结论 此测定方法简便,结果准确、可靠,可用于其它中草药中微量铁元素的测定.     

烟雾箱内甲烷气体的腔增强吸收光谱

用DFB半导体激光器作光源的腔增强吸收光谱(CEAS)技术测量了烟雾箱中甲烷气体在近红外波段的光谱吸收,获得了烟雾箱内甲烷气体在1 315 nm附近的吸收光谱;将测得的光谱数据与Hitran 2004数据库给出的光谱参数做了比较,发现了几条尚未被Hitran 2004数据库收入的甲烷分子的新谱线;同时对CEAS技术定量测量烟雾箱内甲烷气体的能力和稳定性做了研究.结果表明,CEAS技术完全可以用来测量烟雾箱内甲烷气体的吸收光谱,可以作为烟雾箱检测方法的一种补充.     

东南亚近代华人采锡业

华人开采锡矿是东南亚开发史的重要组成部分,它集矿产开发、技术传播、文化交流、经济发展、社会进步于一体,是研究近代中国与东南亚交流的重要历史资料。通过对史料的挖掘与整理,从技术的传播与应用、华人的贡献与作用两个方面,系统地研究华人开发东南亚锡矿发生的历史背景、具体过程,从技术史的视角探讨华人开发东南亚锡矿及其锡矿业发展兴衰的史实。     

UG二次开发中的点云滤波预处理方法和实现

通过UG与Matlab软件的结合,解决UG在逆向工程技术中需要借助他方软件进行点云滤波等预处理的现状.将预处理分为排序、精简、平滑滤波三个步骤,对每一步骤设计可行的算法,利用UG/OpenAPI开发应用接口实现整套算法功能.突破UG可开启文件格式的限制,实时地显示去噪、滤波的效果.实验结果表明,该方法能够提升UG在逆向工程中的应用前景.     

基于三维区域标记对太阳活动区低色球层亮点的统计分析?

研究太阳活动能量的统计分布,以探索日冕物质加热的物理机制.利用一种基于三维区域标记的算法,使用日出卫星拍摄的低色球层λ3968.5单色像时间序列,观测一个处于衰减阶段且爆发频繁的活动区,对多个数量级尺度的亮点进行识别和统计.获得了2.09×104个亮点样本,分析了太阳耀斑基本物理量的频数分布与幂律的关系,以及影响该分布的观测效应.数据分析的主要结果如下:1)低色球层亮点的尺度、面积、光通量服从幂律分布.2)寿命的频数在中等时标呈幂律分布,在长时标呈指数分布;大尺度亮点的等待时间符合指数分布.3)亮点发生率的信噪比随其尺度的增加而减小;小尺度亮点持续的产生有可能向日冕稳定地提供能量.4)微小尺度亮点的频数低于幂律分布,相当程度上受观测数据的低时间分辨率所造成的低采样率影响.     

Identification of differentially expressed genes in photo-period sensitive genic male sterile rice by randomly amplified cDNAs using RAPD primers

The fertile and sterile young panicle representational populations were constructed by bulked sampling method using young panicles in the photo-period sensitive stage of fertility transformation. Two populations were analyzed using cDNA-RAPD. The results showed that: (i) bulked sampling method can be employed to analyze differentially expressed genes using cDNA-RAPD, taking an advantage in avoiding false positive caused by conventional sampling method. (II) Among 150 random primers used, 83 primers amplified the same banding patterns, and 34 primers amplified the same banding pattern but different staining of intensity on gel. (iii) 33 primers amplified differential cDNA bands between fertile and sterile cDNA populations, and the ratio of polymorphism was 22%. It is concluded that there may exist a lot of genes relating to sterility, which makes the differentially expressed cDNA fragments complicated.