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61.
受电缆对地分布电容和电池簇对地分布电容的影响,待机状态下CHB-BESS主电路中流过的电流为较微弱的容性漏电流,回路阻抗大,其储能单元对地电位和交流侧出口电压分布与运行状态有很大不同.靠近并网点的储能单元交流侧电压为矩形波,有效值高;随着与并网点距离的增加,储能单元交流侧电压趋向于正弦波,且电压有效值逐渐减小.测量装置的输入阻抗对C HB-BESS待机状态的电位分布和交流侧出口电压分布也会产生严重影响,需要针对性地对相关设备或电路在待机状态的适应性进行评估方可保证安全. 相似文献
62.
Laura Nicolle Jens Casper Melanie Willimann Cline M. A. Journot Pascal Detampel Toma Einfalt Hiu Man Grisch-Chan Beat Thny Sandrine Gerber-Lemaire Jrg Huwyler 《International journal of molecular sciences》2021,22(8)
There is an increasing interest in cationic polymers as important constituents of non-viral gene delivery vectors. In the present study, we developed a versatile synthetic route for the production of covalent polymeric conjugates consisting of water-soluble depolymerized chitosan (dCS; MW 6–9 kDa) and low molecular weight polyethylenimine (PEI; 2.5 kDa linear, 1.8 kDa branched). dCS-PEI derivatives were evaluated based on their physicochemical properties, including purity, covalent bonding, solubility in aqueous media, ability for DNA condensation, and colloidal stability of the resulting polyplexes. They were complexed with non-integrating DNA vectors coding for reporter genes by simple admixing and assessed in vitro using liver-derived HuH-7 cells for their transfection efficiency and cytotoxicity. Using a rational screening cascade, a lead compound was selected (dCS-Suc-LPEI-14) displaying the best balance of biocompatibility, cytotoxicity, and transfection efficiency. Scale-up and in vivo evaluation in wild-type mice allowed for a direct comparison with a commercially available non-viral delivery vector (in vivo-jetPEI). Hepatic expression of the reporter gene luciferase resulted in liver-specific bioluminescence, upon intrabiliary infusion of the chitosan-based polyplexes, which exceeded the signal of the in vivo jetPEI reference formulation by a factor of 10. We conclude that the novel chitosan-derivative dCS-Suc-LPEI-14 shows promise and potential as an efficient polymeric conjugate for non-viral in vivo gene therapy. 相似文献
63.
针对钛制容器产品试板弯曲角度按现行标准执行中出现的问题,从力学角度进行探讨,导了了试板压弯对所采用的压头直径与试板厚度和延伸率的关系,即D〉(1/δ-1)t,并提出了设定试板弯曲压头直径的新思路。 相似文献
64.
Hung C. Ling Man F. Yan Warren W. Rhodes 《Journal of the American Ceramic Society》1991,74(2):287-289
The aging behavior of a series of lead perovskite dielectrics with the compositions x Pb(Fe2/3 W1/3 )O3 ·(1 – x )Pb(Fe1/2 -Nb1/2 )O3 , where 0 ≤ x ≤ 1, and the effect of dopants were studied. Below the Curie temperature ( T c ), the capacitance and the dissipation factor (tan δ) decrease approximately linearly with logarithmic time. The aging rate depends on the temperature difference, Δ T , between the aging temperature and T c , and on the dopant concentration, but is independent of the measurement frequency between 1 and 1000 kHz. The maximum aging rate is about 3% per decade of time for capacitance and 5% per decade for tan δ at 1 mol% dopant concentration, and increases to 6.3% for capacitance and 8.5% for tan δ at 0.7 mol% dopant concentration. These results are consistent with an aging mechanism caused by changing ferroelectric domain structure with time, as proposed for BaTiO3 . 相似文献
65.
Polymethylphenylsilsesquioxane (PMPSQ–OH) and trimethylsilyl end‐blocked PMPSQ (PMPSQ–EC) were prepared. The thermal decomposition behavior of these polymers was studied by thermogravimetric analysis (TGA) and FT‐Raman spectroscopy. Hydroxyl‐functionalized polystyrene (PS–OH) was also prepared by anionic living polymerization. Thin hybrid films of PMPSQ/PS–OH with various blend ratios were obtained by spin‐coating on freshly cleaned glass. The surface morphology of the hybrid films was investigated by atomic force microscopy (AFM). In 80/20 PMPSQ/PS–OH hybrid film, the PS–OH component produced a very uniformly dispersed phase. This hybrid film contained small domains of PS–OH whose size ranged from 60 to 80 nm. As the content of PS–OH was increased, the domain morphology coarsened and phase inversion took place around 50 wt %. In the phase‐inversed system, the PMPSQ‐rich phase was uniformly distributed in the PS–OH‐rich continuous phase. In addition, temperature‐dependent dielectric properties of PMPSQ/PS–OH hybrids were investigated. Relaxation of the hybrids was observed with an increasing content of the PS–OH component due to the amorphous glass transition behavior of PS–OH. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2801–2812, 2003 相似文献
66.
Ozonolysis of cyclododecene was carried out to produce an w-formyl carboxylic acid (12-oxododecanoic acid) which is derived
from zwitterion and aldehyde moiety that are formed during the reaction. The ozonolysis was performed to examine the product
distribution under such reaction variables as temperature, kinds of solvent, and presence of catalyst. The yield of polymeric
ozonide, which is undesirable product, was measured to be dominantly 86% without pyridine catalyst, whereas, only 10.25% with
the catalyst. The optimum reaction condition was to be in MC (methylene chloride) solvent, and in the presence of equimolar
olefin and pyridine catalyst at O°C, at which the yields of polymeric ozonide, 1,12-dodecanedialdehyde, 1,12-dodecanedicarboxylic
acid, and 12-oxo-dodecanoic acid were 10.25%, 26.72%, 26.31%, and 36.72%, respectively. 相似文献
67.
Yun‐Jia Li Man Xu Jun‐Qiang Feng Xiao‐Long Cao Yan‐Fei Yu Zhi‐Min Dang 《应用聚合物科学杂志》2007,106(5):3359-3365
Through the use of polyethylenes with different crystallinities as matrices, the effects of the matrix crystallinity on the percolation threshold and dielectric behavior of percolative composites have been investigated. The results suggest that the percolation threshold is negatively related to the matrix crystallinity, whereas the enhancement of the dielectric constant is positively related to the matrix crystallinity. A two‐dimensional diagram is proposed to illustrate such relationships. In addition, it has been found that the insulator–conductor transition is much flatter in low‐crystallinity‐matrix‐based composites, and this may be favorable for preparing threshold composites with a high dielectric constant and a low loss tangent. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 相似文献
68.
Mesoporous molecular sieve MCM-41 with a Si/Al ratio of 35 was obtained by hydrothermal synthesis using a gel mixture with a molar composition of 6 SiO20.1 Al2O31 hexadecyltrimethylammonium chloride 0.25 dodecyltrimethylammonium bromide 0.25 tetrapropylammonium bromide0.15 (NH4)2O1.5 Na2O300 H2O. The MCM-41 sample was calcined in O2 flow at 813 K and subsequently ion exchanged with Ca2+. A small Pt cluster has been supported on the MCM-41 sample following a procedure using ion exchange of Pt(NH3)
4
2+
. The Pt(NH3)
4
2+
ion supported on MCM-41 has been activated in O2 flow at 593 K and subsequently reduced with Fh flow at 573 K, in the same way used for the preparation of a Pt cluster entrapped inside the supercage of zeolite NaY. The resulting Pt cluster supported on the MCM-41 shows hydrogen chemisorption oftotal two H atoms per Pt at 296 K (based on the total amount of Pt) and high catalytic activity for hydrogenolysis of ethane. The chemical shift in129Xe NMR spectroscopy of adsorbed xenon indicates that the Pt cluster is located inside the mesoporous molecular sieve. 相似文献
69.
70.
Summary Three new phenothiazine-containing electrono-donor monomers: methacryloyl-2-hydroxyethyl-2-(N-phenothiazinyl)propionate (i) acryloyl-2-hydroxyethyl-2-(N-phenothiazinyl) propionate (ii) and 2-(N-phenothiazinyl) propionic acid vinyl ester (iii) were synthesized and radically polymerized. The ionization potentials of poly(i), poly(iii) and of the model for the structural unit of the acrylic polymers: acetyl-2-hydroxyethyl-2-(N-phenothiazinyl) propionate determined with two small acceptors were discussed in terms of sterical hindrances. 相似文献