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101.
Floc size has substantial impact on sludge dewaterability, which might be increased or reduced after freezing and thawing. It is commonly assumed that floc size would be increased by low-speed freezing, with a planar ice front rejecting most flocs ahead of it to form large aggregates. We demonstrate in this work that an advancing planar ice front can not only engulf an activated sludge floc of size 3030 mum, but also fragment it. During floc freezing, when the ice engulfed a thin layer of floc, the latter would be pulled apart vertically by the action of the former. This particular portion of floc was then axially elongated and fixed in the frozen layer, with accumulated force pushing upward. In the present test the floc's vertical length was increased by over 92% and its width decreased by 37% over freezing. The force measurement and floc morphology tracking revealed that the force gradient that pulled apart the floc was 0.0027 N/m. The floc under investigation was fragmented at the point where the normal stress acting on the interior network exceeded 8 Pa. 相似文献
102.
用质谱技术对钾、钙同位素体系特征参数测定的初探 总被引:1,自引:0,他引:1
报道了用FinniganMAT 2 62质谱技术和同位素稀释法测定了光谱纯CaO和国际二级标准Tahiti(CaCO3)的同位素40 Ca 42 Ca比值以及后者的40 Ca含量 ,RSD分别为 0 .0 2 %和 0 .1 %。对国家钾标样的测定表明 :39K、40 K和41 K同位素丰度分别为 0 .93 2 60± 0 .0 0 1 2、0 0 0 0 1 1 2 0± 0 .0 0 0 0 1 2 9和 0 .0 672 86± 0 .0 0 0 1 2 5。其中39K含量为 0 .1 2 1 72± 0 .0 0 0 2 9,与标准值在误差范围内一致。实验测定结果为在我国开展40 K 40 Ca同位素体系的定年和环境的示踪研究打下了基础 相似文献
103.
104.
<正> 前文我们报告了含有芳香叔胺基的丙烯酸酯、甲基丙烯酸-4-N,N-二甲氨基苄酯(DMABMA)在过氧化二月桂酰(LPO)引发下的聚合动力学。从所得的聚合速度方程式及低的聚合活化能,认为DMABMA与LPO形成氧化还原体系而使DMABMA聚合,在本文第Ⅳ报中报道了DMABMA不仅能引发甲基丙烯酸甲酯的聚合,还参与聚甲基丙烯酸甲酯的链中,因此称这种既能参与引发聚合反应,又参与聚合物链中的引发“引发剂单体(initiatomer)”。这种含有可聚合胺引发体系的优点是,用于丙烯酸酯类医用 相似文献
105.
106.
A bio-mimic bulk acoustic wave (BAW) sensor was fabricated by coating the caffeine (CAF) template molecular imprinting polymer (MIP). This sensor exhibited high selectivity and a sensitive mass response to CAF. The response range of the sensor was between 5.0 x 10(-9) and 1.0 x 10(-4) M with a detection limit of 5.0 x 10(-9) M at pH 8.0. Recoveries were 96.1-105.6%. Influencing factors were investigated in detail and optimized. When employed to detect real samples, the proposed method proved to be a convenient method with the advantages of high sensitivity, good selectivity and ease of handling. 相似文献
107.
A novel compound, [Co(phen)3][V10O26]·H2O, was hydrothermally synthesized and characterized by single-crystal X-ray diffraction. This compound crystallizes in the orthorhombic space group Ccca with a=13.447(3), b=29.936(6), c=23.252(5) Å, V=9360(3) Å3, Z=8 and R=0.0285. Data were collected on a Rigaku R-AXIS RAPID IP diffractometer at 293 K in the range of 1.36<θ<24.99°. The structure of the compound consists of vanadium oxide layers, which are built up from the infinite VO4 chains by corners and edges sharing. The [Co(phen)3]2+ complexes occupy the interlayer space and contact each other via π−π stacking interactions of the phen groups to form infinite one-dimensional chains. 相似文献
108.
[structure: see text]. A new series of dendritic two-photon absorbing chromophores containing triphenylamine moiety as a core or branching points have been synthesized through a convergent synthetic strategy. One-photon and two-photon optical properties of these molecules were characterized. In the nanosecond time domain, these molecules exhibited large two-photon absorption (TPA) cross sections up to 7.56-12.2 x 10(-44) s cm(4) at 800 nm, indicating that these molecular structures were viable candidates for various two-photon related applications. 相似文献
109.
A high-performance capillary electrophoresis with electrochemical detection (CE-ED) method has been employed for the determination of six bioactive ingredients in traditional Chinese herbs, Herba cepbalanoplosis segeti and Herba cirsii japonici. The effects of several factors such as the acidity and concentration of running buffer, the separation voltage, the applied potential and the injection time on CE-ED were investigated. Under the optimum conditions, the six analytes could be well separated within 21 min in a 75 cm length capillary at the separation voltage of 15 kV in a 50 mmol L–1 borax running buffer (pH 8.4). A 300 m diameter carbon disk electrode was used as the working electrode positioned carefully opposite the outlet of the capillary in a wall-jet configuration at potential of +950 mV (vs. SCE). Good linear relationship was established between peak current and concentration of analytes over two orders of magnitude with detection limits (S/N=3) ranged from 1.5×10–7 to 6.0×10–7 g mL–1 for all six analytes. This proposed method has been successfully applied for the analysis of traditional Chinese herbs after a relatively simple extraction procedure, further on, for the differentiation of these above two seemingly identical herbs based on their electropherograms or characteristic electrochemical profiles. 相似文献
110.
Bian HD Gu W Xu JY Bian F Yan SP Liao DZ Jiang ZH Cheng P 《Inorganic chemistry》2003,42(14):4265-4267
The first mu(3)-oxalato-bridged copper(II) complex, [[Cu(3)(L)(3)(mu(3)-C(2)O(4))][Cu(L)(H(2)O)](ClO(4))(2)] x 0.5(H(2)O) x 0.5(CH(3)OH), where HL = N-ethyl-N'-salicylidene-1,2-diaminoethane, has been synthesized and characterized by variable-temperature magnetic susceptibility measurement. The complex exhibits ferromagnetic coupling between the oxalato-bridged copper atoms and antiferromagnetic coupling between the oxygen-bridged copper atoms. 相似文献