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排序方式: 共有490条查询结果,搜索用时 359 毫秒
91.
He Jie Man-Ling Jia Chang-Bin Tan Jin-Sheng Sun 《Korean Journal of Chemical Engineering》2011,28(11):2190-2195
A co-current operation for SO2 absorption by water was performed in a laboratory-scale packed column. The effects of L/V (liquid-gas ratio) and F (gas phase
loading factor) on the SO2 absorptivity were both investigated. The absorptivity for co-current increased with the increase of L/V and the percentage
of absorptivity increase at higher L/V is larger. At lower F, in regular packing there is fluctuation of absorptivity with
F increased, but in random packing there is not. With the increase of F, the absorption curve slowed down. It is proposed
that in order to obtain a steady desulfurization efficiency, F factor in both kinds of packings should be higher than 4 kg0.5/m0.5s. For absorptivity, which could be reached by both co-current and counter-current, it is suggested that co-current is better
because of the higher gas velocity. 相似文献
92.
Abstract We study a key inequality that implies the lower bound formula for the probability of correct selection and other selection-related events of interest in the Levin-Robbins-Leu family of sequential binomial subset selection procedures. We present a strategy for the proof of the key inequality, and a mostly complete general proof is given. The strategy provides an entirely complete and rigorous proof of the inequality for as many as seven competing populations using computer-assisted symbolic manipulation. 相似文献
93.
Shih‐Tong Hsu Lung‐Chuan Chen Min‐Her Leu Wen‐Feng Hsiao Wen‐Ya Lee Ting‐Chung Pan 《Polymer Engineering and Science》2013,53(3):468-473
Chitosan with 45% deacetylation (CS45) grafted poly (acrylic acid) (CS45‐g‐PAA) was synthesized and characterized as an adsorbent of paraquat. CS45‐g‐PAA copolymers were prepared using H2O2(aq) as an initiator and NH4OH(aq) as a promoter. The highest grafting percentage of 44.2% was obtained using the traditional kinetic method. However, a maximum grafting percentage of 52.6% was calculated for the central composite design (CCD). Experimental results based on the reaction conditions that were predicted from the CCD are consistent with theoretical calculations. The grafted copolymer was characterized by FTIR, BET, and SEM. A representative CS45‐g‐PAA copolymer was hydrolyzed to a salt type (CS45‐g‐PANa) and used in the adsorption of paraquat. The adsorption equilibrium data correlate more closely with the Langmuir isotherm than with the Freundlich equation. The maximum adsorption capacity of CS45‐g‐PANa is 396.7 mg/g‐adsorbent. This value clearly exceeds that of Fuller's earth and the activated carbon which is the most commonly used binding agent for paraquat. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers 相似文献
94.
Li-Hua Guo Hui Li Fang Wang Jia Yu Jin-Sheng He 《International journal of molecular sciences》2013,14(7):14171-14184
The discovery of microRNAs (miRNAs) provides a new and powerful tool for studying the mechanism, diagnosis and treatment of human cancers. Currently, the methylation epigenetic silencing of miRNAs with tumor suppressor features by CpG island hypermethylation is emerging as a common hallmark of different tumors. Here we showed that miR-433 and miR-127 were significantly down-regulated in gastric cancer (GC) tissues compared with the adjacent normal regions in 86 paired samples. Moreover, the lower level of miR-433 and miR-127 was associated with pM or pTNM stage in clinical gastric cancer patients. The restored expression of miR-433 and miR-127 in GC cells upon 5-Aza-CdR and TSA treatment suggested the loss of miR-433 and miR-127 was at least partly regulated by epigenetic modification in GC. Furthermore, the ectopic expression of miR-433 and miR-127 in gastric cancer cell lines HGC-27 inhibits cell proliferation, cell cycle progression, cell migration and invasion by directly interacting with the mRNA encoding oncogenic factors KRAS and MAPK4 respectively. Taken together, our results showed that miR-433 and miR-127 might act as tumor suppressors in GC, and it may provide novel diagnostic and therapeutic options for human GC clinical operation in the near future. 相似文献
95.
W. S. Chow Y. Y. Leu Z. A. Mohd Ishak 《Polymer-Plastics Technology and Engineering》2013,52(8):858-863
Injection-molded poly(lactic acid)/organo-montmorillonite (PLA/OMMT) and poly(lactic acid)/ nano-precipitated calcium carbonate (PLA/NPCC) were exposed to a water absorption test at 30°C for 70 days. The analysis was focused on the water diffusion kinetics and impact strength changes induced by the hydrolysis. The diffusion exponent (n) values of all the PLA samples are less than 0.5, indicating the Fickian diffusion model (case I) is obeyed. Adding nanofillers and maleated rubbers (SEBS-g-MAH or EPR-g-MAH) increased equilibrium moisture content but decreased diffusion coefficient values of PLA. The recoverability and retention-ability of the maleated rubbers toughened PLA/OMMT and PLA/NPCC after water absorption are excellent. 相似文献
96.
97.
This paper employs simple rolling process plus annealing to refine the grain size of magnesium alloy ZK60. This goal is effectively
achieved, obtaining grains as fine as ∼3.7 μm. Such a specimen shows an elongation of 642%, and its ultimate fracture surface
exhibits intergranular separation and significant grain growth. Additionally, the effects of the specimen’s geometry and tensile
test axis with respect to the rolling direction on superplastic elongation is studied, which has not been done before. 相似文献
98.
硅基PbSe/BaF2/CaF2薄膜及其光电特性 总被引:1,自引:1,他引:0
采用分子束外延方法在Si(111)衬底上生长了PbSe/BaF2/CaF2薄膜,扫描电镜和X-光衍射分析显示,通过生长BaF2/CaF2缓冲层的方法,在Si(111)衬底上外延的PbSe薄膜晶体质量高,PbSe表面光亮,无形裂现象发生,X-光衍射峰峰宽窄(153arcs)。外延生长的PbSe薄膜被应用于制作光电二极管,首次采用热蒸发金属铝膜在PbSe表面形成Al-PbSe肖特基结光电二极管,获得了比Pb-PbSe肖特基结更为稳定和理想的电流-电压特性曲线。 相似文献
99.
Chin-Chuan Chen Chi-Yuan Chen Shu-Fang Cheng Tzong-Ming Shieh Yann-Lii Leu Wen-Yu Chuang Kuang-Ting Liu Shir-Hwa Ueng Yin-Hwa Shih Li-Fang Chou Tong-Hong Wang 《International journal of molecular sciences》2021,22(18)
Molecules involved in DNA damage response (DDR) are often overexpressed in cancer cells, resulting in poor responses to chemotherapy and radiotherapy. Although treatment efficacy can be improved with the concomitant use of DNA repair inhibitors, the accompanying side effects can compromise the quality of life of patients. Therefore, in this study, we identified a natural compound that could inhibit DDR, using the single-strand annealing yeast-cell analysis system, and explored its mechanisms of action and potential as a chemotherapy adjuvant in hepatocellular carcinoma (HCC) cell lines using comet assay, flow cytometry, Western blotting, immunofluorescence staining, and functional analyses. We developed a mouse model to verify the in vitro findings. We found that hydroxygenkwanin (HGK) inhibited the expression of RAD51 and progression of homologous recombination, thereby suppressing the ability of the HCC cell lines to repair DNA damage and enhancing their sensitivity to doxorubicin. HGK inhibited the phosphorylation of DNA damage checkpoint proteins, leading to apoptosis in the HCC cell lines. In the mouse xenograft model, HGK enhanced the sensitivity of liver cancer cells to doxorubicin without any physiological toxicity. Thus, HGK can inhibit DDR in liver cancer cells and mouse models, making it suitable for use as a chemotherapy adjuvant. 相似文献
100.
R. H. Horng D. S. Wuu C. C. Leu S. H. Chan T. Y. Huang S. M. Sze 《Microelectronics Reliability》2000,40(4-5)
The effects of F-ion implantation on the leakage and dielectric properties of the Ba0.7Sr0.3TiO3 (BST) films were investigated. The BST film implanted with 1×1015 cm–2 shows the optimum leakage performance. The leakage current density can be decreased by one order of magnitude as compared to that of the non-implanted sample at an applied voltage of 2 V. On increasing the implanted dose from 5×1014 to 5×1015 cm–2, the dielectric constant first increases and then decreases due to the deteriorated crystallinity. It is found that the suitable F-ion dose can reduce the –OH contaminants and improve the dielectric and leakage properties. 相似文献