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排序方式: 共有40条查询结果,搜索用时 31 毫秒
31.
Li D  Wen F  Wang Q  Zhao Y  Li F  Bao B 《Optics letters》2008,33(3):210-212
A radial shearing (RS) interferogram obtained by the carrier fringe method is essentially the combination of radial and lateral shearing. The previous phase reconstruction algorithm neglects the effect of lateral shearing on the obtained RS interferogram. A mathematical formula for wavefront reconstruction from an RS interferogram is deduced. If the phase difference of the tested wavefront phase, the RS ratio s, and the laterally sheared amount x(0) in the x direction and y(0) in the y direction, respectively, have been determined, the tested wavefront phase can be precisely reconstructed using this formula. The result of simulation analysis and experiment shows that the formula is correct and more accurate.  相似文献   
32.
In the littlest Higgs model with T-parity, we discuss the pair production of the T-odd top partner(T_) that decays almost 100% into the top quark and the lightest T-odd particle(A_H). Considering the current constraints,we investigate the observability of the T-odd top partner pair production through the process pp→T_T_→tt A_HA_H in the final states with two leptons at 14 TeV LHC. We analyze the signal significance and found that the lower limits on the T-odd top partner mass are approximately 1.2 TeV, 1.3 TeV, and 1.4 TeV at the 2σ confidence level at 14 TeV LHC with an integrated luminosities of 30 fb~(-1), 100 fb~(-1), and 300 fb~(-1), respectively. This lower limit can be increased to approximately 1.5(1.6) TeV if we used 1000(3000) fb~(-1) of the integrated luminosity.  相似文献   
33.
用Fe_3(CO)_(12)与亚磷酸三硫代苯酯P(SC_6H_5)_3反应得到标题化合物。P(SC_6H_5)_3以其裂解分子片SC_6H_5和P(SC_6H_5)_2配位。用X-ray衍射技术测定了该化合物的晶体结构,晶体属正交晶系,空间群为Pbca,a=17.422(7),b=10.634(6),c=28.987(12)A;V=5370A~3,z=8,D_c=1.579g·cm~(-3)。由直接法和差值Fourier合成解出全部非氢原子坐标,并用全矩阵最小二乘法修正,最后偏离因子R=0.054,R_w=0.058, 分子结构中心的Fe_2SP折叠环沿S…P线或沿Fe-Fe键折叠的二面角(分别为76.1°和82°)比其它具有中心Fe_2S_2,Fe_2P_2和Fe_2SP折叠环的类似化合物中的相应值小,Fe-Fe键长为2.572A,Fe-S(1)-Fe=68.6°,Fe-P-Fe=70.7°。  相似文献   
34.
Rh2(μ-SC6H5)2(CO)4的合成和晶体结构   总被引:2,自引:0,他引:2  
一种路易斯碱,例如膦(PR3)或异氰化物(CNR)加到双核或多核络合物中,会导致低核物种的形成,这就伴随有金属一金属键的断裂[1].这样的例子很多,如我们曾用F33(CO)12与P(SC6H5)3反应,分离出三个不同的两核铁数合物[2].现在我们报导另一个例子:用Rh4(CO)12与P(SC6H小反应,同样也得到一个两核物种WhZ(P-SC6H巾(C)4.该化合物首先由B0ltoll*等人用WhZ(CO)ZC12与苯硫酚C6H。SH反应得到,但有关它的X-rar晶体结构的测定还未见报导·与之相似的化合物Rh。(p-SC。H。F)。门O)。的结构已由ClaverN…  相似文献   
35.
A novel type of carboxylated multiwalled carbon nanotube modified electrode(c-MWCNTs/GCE) was constructed and the electrochemical properties of phenacetin(PHE) at it were studied. In a buffer solution of 0.1 mol/L HAc-NaAc(pH=5.3), PHE exhibited a couple of quasi-reversible redox peaks and an anodic peak in the poten- tial range of 0.2--1.2 V at c-MWCNTs/GCE. The peak current was proportional to the concentration of PHE in the range of 4.0× 10^-6_ 1.0 × 10^-4 mol/L with a detection limit of 1.0× 10^-6 mol/L(S/N=3). The c-MWCNTs/GCE showed excellent repeatability and stability and the electrochemical reaction mechanism of PHE was proposed. This method was used to determine the content of PHE in medical tablets and the recovery was determined to be 96.5%--104.2% by means of a standard addition method.  相似文献   
36.
2-氨基-1,3,4-噻二唑的抗水稻白叶枯病机制的探讨   总被引:4,自引:0,他引:4  
药师寺国人等于1971年发现2-氨基-1,3,4-噻二唑(ATDA)具有优越的抗水稻白叶枯病菌的性能,并发现这种性能可被烟酰胺抵消.一般认为,ATDA的作用与细菌细胞中烟酰胺的代谢有关.为了探明ATDA的活性与结构的关系,并从中找出有效的同类化合物,进一步了解这个药剂的抗病机制,我们合成了几类新的噻二唑化合物,连同以前报导的  相似文献   
37.
An ODS packing material was specially designed for CEC to achieve high efficiency. The size of the particles was approximately 3.2 m based on scanning electron microscopy, and the average pore size of the particles was 1500 Å by mercury intrusion porosimetry measurement. The packing materials were used in sol-gel bonded continuous-bed columns. The performance of columns containing these 3 m, 1500 Å ODS particles was evaluated for CEC and compared to 3 m, 80 Å ODS particles. The electroosmotic velocity (EOF) for the 1500 Å ODS material was slightly greater than that for the 80 Å ODS material. An efficiency of 410,000 plates m–1 was obtained for unretained thiourea with a 30 cm × 75 m i.d. 1500 Å ODS column, which was more than 2 times higher than the efficiency obtained from the 80 Å ODS column.Dedicated to Professor K. Jinno on the occasion of his 60th, birthday.  相似文献   
38.
薛昆鹏  俞灵钰  任兴发  屠炳芳  陈超  徐婷  何欢  胡帅 《色谱》2023,41(3):265-273
建立了改进的固相萃取-高效液相色谱法测定土壤中甲醛、乙醛、丙烯醛、丙酮、丙醛、丁烯醛、丁醛、苯甲醛、异戊醛、正戊醛、邻-甲基苯甲醛、间-甲基苯甲醛、对-甲基苯甲醛、正己醛和2,5-二甲基苯甲醛等15种醛酮类化合物的分析方法。利用乙腈对土壤进行超声提取,样品提取液与2,4-二硝基苯肼(2,4-DNPH)进行衍生化反应,生成稳定的腙类化合物;随后利用装有亲水亲脂平衡的N-乙烯基吡咯烷酮/二乙烯基苯共聚物填料的固相萃取小柱(Welchrom^(■)BRP)对衍生后的溶液进行净化;采用Ultimate^(■)XB-C_(18)色谱柱(250 mm×4.6 mm,5μm)进行分离,以乙腈-水(65∶35,v/v)为流动相进行等度洗脱,于波长360 nm处进行检测,利用外标法对土壤中15种醛酮类化合物进行定量。该方法改进了环境标准HJ 997-2018《土壤和沉积物醛、酮类化合物的测定高效液相色谱法》中试样的处理方法,优化后得到土壤的最佳提取条件,即:提取溶剂为乙腈,提取温度为30℃,提取时间为10 min。结果表明:采用BRP小柱的净化效果明显优于普通硅胶基质C_(18)小柱,15种醛酮类化合物在各自的范围内线性关系良好,线性相关系数均在0.996以上;平均加标回收率为84.6%~115.9%,相对标准偏差(RSD)为0.2%~5.1%;检出限为0.02~0.06 mg/L。该方法简便,灵敏度高,准确性好,适用于HJ 997-2018中规定的土壤和沉积物中15种醛酮类化合物的准确定量分析,为研究土壤中醛酮类化合物的残留状况和环境行为提供了可靠的技术支持。  相似文献   
39.
Broccolini (Brassica oleracea Italica?×?Alboglabra) is a hybrid of broccoli and kai-lan, Chinese broccoli. To date, no study has been reported on the chemical composition of the volatile fractions of this raw material. In this study, the volatile constituents from the ethanolic extract of broccolini leaves were analysed by gas chromatography-mass spectrometry (GC-MS). Sixteen compounds were identified. The major components include 5-phenyl-undecane (11%), n-hexadecanoic acid (9.34%), octadecanoic acid (6.39%), 1,1,3-trimethyl-3-phenyl-indan (4.0%), 3-(2-phenylethyl)benzonitrile (3.48%) and phytol (3.37%).  相似文献   
40.
本文从打靶成绩评价中总结出一个数据评价的重要结论,并以此为基础讨论了不同情况下评价精密度和准确度的方法,从而归纳出数据评价的一般判定方法。  相似文献   
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