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Mass concentration and isotopic values δ13C and 14C are presented for the water-insoluble refractory carbon(WIRC) component of total suspended particulates(TSP),collected weekly during 2003,as well as from October 2005 to May 2006 at the WMO-GAW Mt.Waliguan(WLG) site.The overall average WIRC mass concentration was(1183±120)ng/m3(n = 79),while seasonal averages were 2081 ±1707(spring),454±205(summer),650±411(autumn),and 1019±703(winter) ng/m3.Seasonal variations in WIRC mass concentrations were consistent with black carbon measurements from an aethalometer,although WIRC concentrations were typically higher,especially in winter and spring.The δ13C PDB value(-25.3 ± 0.8)%.determined for WIRC suggests that its sources are C3 biomass or fossil fuel combustion.No seasonal change in δ13C PDB was evident.The average percent Modern Carbon(pMC) for 14C in WIRC for winter and spring was(67.2 ± 7.7)%(n = 29).Lower pMC values were associated with air masses transported from the area east of WLG,while higher pMC values were associated with air masses from the Tibetan Plateau,southwest of WLG.Elevated pMC values with abnormally high mass concentrations of TSP and WIRC were measured during a dust storm event. 相似文献
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Xiaoying Xie Wenwen Liu Luyang Zhao Chengde Huang 《Journal of Solid State Electrochemistry》2010,14(9):1585-1594
Manganese–vanadium oxide had been synthesized by a novel simple precipitation technique. Scanning electron microscopy, X-ray
diffraction, Brunauer–Emmett–Teller, thermogravimetric analysis/differential scanning calorimetry, and X-ray photoelectron
spectroscopy were used to characterize Mn–V binary oxide and δ-MnO2. Electrochemical capacitive behavior of the synthesized Mn–V binary oxide and δ-MnO2 was investigated by cyclic voltammetry, galvanostic charge–discharge curve, and electrochemical impedance spectroscope methods.
The results showed that, by introducing V into δ-MnO2, the specific surface area of the mixed oxide increased due to a formation of small grain size. The specific capacitance
increased from 166 F g−1 estimated for MnO2 to 251 F g−1 for Mn–V binary oxide, and the applied potential window extended to −0.2–1.0 V (vs. saturated calomel electrode). Through
analysis, it is suggested that the capacitance performance of Mn–V binary oxide materials may be improved by changing the
following three factors: (1) small grain and particle size and large activity surface area, (2) appropriate amount of lattice
water, and (3) chemical state on the surface of MnO2 material. 相似文献
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1 引 言无界连续函数 ,特别是大范围无界连续函数的逼近理论的重要意义如所知是无容置疑的 一个行之有效的方法称作扩展乘数法 ,它由徐利治和王仁宏教授首先提出[1~ 3 ] ,之后得到很大发展[4,5 ] 本文在扩展乘数法中引入经典“试探函数”1 ,x ,x2 ,构造了一个线性正算子能否改造为逼近任意无界连续函数的判别定理 ,并利用该定理建立了变形的Мираквян奇异积分算子的收敛性定理 ,由此可以很容易地得到许多有价值的结论 实例分析表明 ,这种结合既有理论价值又有实际意义2 全轴上无界连续函数逼近的收敛性定理设E是一个Ba… 相似文献
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本文给出了原子和离子能量表达式中的库仑积分与交换积系数f^k,g^k的计算方法,同时给出了计算中所涉及的Racah系数,U^(^K^),V^(^K^)和C^(^K^)矩阵等光谱参量的计算方法,用FORTRANⅣ语言编写了关于f^k和g^k的计算机程序,只要输入与光谱项有关的量子数,即可迅速得到相应的k^f,g^k值,避免了烦琐的人工推算。 相似文献
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A combination of a DNA ligase and a restriction endonuclease provides a DNA polymerase activity, which might suggest a novel strategy for polymer synthesis. 相似文献
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This paper reports an improved catalytic molecular beacon. Addition of the target oligonucleotide activates a DNA enzyme (DNAzyme), which, in turn, activates multiple copies of molecular beacons (MB) and gives rise to a strong fluorescence signal. In a previous design, the activated DNAzyme could oligomerize, especially dimerize, and result in inactivation of the DNAzyme. The current design avoids this problem, upon activated by the target DNA, the DNAzyme will stay constantly active. With the improved method, a detection of 10 pM DNA has been demonstrated, which is 1000 times more sensitive than the method previously reported. 相似文献