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71.
Hui Zhi Shirley Lee Prof. Weng Kee Leong Dr. Siden Top Dr. Anne Vessières 《ChemMedChem》2014,9(7):1453-1457
A structure–activity relationship (SAR) study of the triosmium carbonyl cluster Os3(CO)10(NCCH3)2 was carried out with a series of clusters of the general formula Os3(CO)12?nLn, cationic osmium clusters and a hemi‐labile maltolato‐Os cluster. The SAR results showed that good solubility in DMSO and at least one vacant site are required for cytotoxicity. In vitro evaluation of these new compounds showed that some are selectively active against estrogen receptor (ER)‐independent MDA‐MB‐231 breast cancer cell lines relative to ER‐dependent MCF‐7 breast cancer cells, suggesting that the compounds have a different biological target specific to MDA‐MB‐231 cells. In particular, the maltolato cluster exhibits strong antiproliferative activity, with an IC50 value of 3 μM after only 24 h incubation. Additionally, biochemical assays conducted with the cationic cluster show that it induces apoptosis, although a biological target has not yet been identified. Further research to establish the molecular targets of these compounds and to develop improved organometallic clusters as potential breast cancer therapeutics is underway. 相似文献
72.
Two series of anionic water‐borne polyurethanes with alkali resistance and covalent bonds of a reactive dye were synthesized with different molar ratios of poly(tetramethylene glycol) (PTMG). They were classified with respect to PTMG 1000 and PTMG 2000. The fiber blends of polyester/nylon nonwoven fabrics were dipped into silicon‐containing, water‐borne polyurethane and squeezed to an 80% pickup ratio. Finally, the manmade leather was treated with alkali reduction and dyed with a reactive dye. The alkali reduction and the thermal, mechanical, and dyeing properties of the manmade leather were studied. For alkali reduction, different ratios of NaOH and Na2CO3 concentrations were used. Na2CO3 was used because of its better spreading and buffering properties. The softness and breaking load were measured and related to the weight reduction. For the dyeing properties, a reactive dye with vinyl sulfone groups was found to bond with the OH group of water‐borne polyurethane by covalent bonding. On the basis of alkali reduction, a mixture of NaOH and Na2CO3 with a concentration ratio of 0.1N/0.2N could lead to better softness and alkali reduction of leather. For the mechanical properties, leather of the PTMG 1000 series showed a higher breaking load than leather of the PTMG 2000 series. However, less elongation in the PTMG 1000 series resulted. Differential scanning calorimetry showed an endothermic peak at 50–100°C. This indicated that the glass‐transition temperature of the hard segment decreased with an increasing amount of the soft segment in leather; meanwhile, both the glass‐transition temperature of the soft segment and the melting temperature of the hard segment also decreased as the content of the soft segment increased. For the dyeing properties, the reactive blue dye could reach up to 96.1% dye uptake in the polyurethane part of the leather. Moreover, the washing fastness could be graded as high as 4–5, and the light resistance was also graded to 4–5, in the dyed leather. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2324–2335, 2005 相似文献
73.
文章介绍了一种基于AD1674数/模转换的材料性能测试系统的用途、结构组成、工作原理等,阐述了该测试仪器电子控制系统的硬件设计,包括控制单片机、数字、模拟电路、输入输出设备等. 相似文献
74.
Abstract This paper proposes a curve for the one‐dimensional search method in optimization problems. The search is along a curve instead of a line. This curve is determined by a parameter [u] from the following three points: (1) the initial point Xo, (2) the Cauchy point Xc, (3) the Newton point XN, and has the following four characteristics: (1) tangents to the steepest descent direction at Xo, (2) passes through XN, (3) decreases monotonically from Xo to XN for a quadratic function, (4) no complex computation on the parameter u. Therefore, the proposed method has the following advantages: (1) it is globally convergent, (2) it is locally q‐quadratically (or q‐superlinearly for quasi‐Newton point) convergent, (3) the search procedure is as simple as the line search method. 相似文献
75.
Siping Zhou Bevis W. L. Mak Echo Leong Kan Hon-Shing Ip Shu-kuen Liu Tze-Kwan 《Water and Environment Journal》2010,24(2):140-146
Stability of sludge blanket is a critical factor controlling the performance of clarifiers. A three-dimensional computational fluid dynamics (CFD) model was applied to optimize the clarifier design at the Tai Po Sewage Treatment Works, Hong Kong. Validated by field data, the CFD model evaluated the key clarifier design elements including side-water depth, centre-feed inlet, flocculation well and returned activated sludge (RAS) flow. Based on field observations and modelling results, the new design aims at eliminating the strong turbulence typical of centre-feed inlets in the clarifier, thus creating a better flocculation environment, and reducing disturbance to the sludge blanket. The modelling results also demonstrated a marked improvement in clarifier performance after the increase in clarifier depth and hence sludge storage capacity. The increased storage capacity reduces the risk of high sludge blanket levels upsetting the clarified effluent quality under high flow or solids loading conditions. 相似文献
76.
We report a systematic investigation of the temperature dependence of electrical resistance behaviours in tri- and four-layer graphene interconnects. Nonlinear current–voltage characteristics were observed at different temperatures, which are attributed to the heating effect. With the resistance curve derivative analysis method, our experimental results suggest that Coulomb interactions play an essential role in our devices. The room temperature measurements further indicate that the graphene layers exhibit the characteristics of semiconductors mainly due to the Coulomb scattering effects. By combining the Coulomb and short-range scattering theory, we derive an analytical model to explain the temperature dependence of the resistance, which agrees well with the experimental results. 相似文献
77.
78.
Chung-Chun Chen Chao-Chieh Li Bo-Jr Huang Kun-You Lin Hen-Wai Tsao Huei Wang 《Microwave Theory and Techniques》2009,57(9):2173-2183
This paper proposes a new ring-based triple-push voltage-controlled oscillator (VCO) architecture to achieve a wide tuning range and high operating frequencies. Two ring-based triple-push VCOs, one with a continuous frequency tuning range of 0.2-34 GHz, fabricated in 0.13- mum CMOS, and the other with a range of 0.1-65.8 GHz, fabricated in 90-nm CMOS, are presented in this paper. These two VCOs demonstrate that the proposed VCO architecture can achieve a very wide continuous tuning range, up to millimeter-wave frequencies, without any device-switching operations. In addition to the wide tuning range, the chip area of the proposed VCO is very small, allowing integration into a phase-locked loop. The power consumptions of the 0.2-34- and 0.1-65.8-GHz VCOs are 2-70 mW from a 2-V supply voltage, and 1.2-26.4 mW from a 1.2-V supply voltage, respectively. The fundamental and second harmonic rejections are better than 15 dB for both VCOs. 相似文献
79.
Tunable Spectrum Selectivity for Multiphoton Absorption with Enhanced Visible Light Trapping in ZnO Nanorods 下载免费PDF全文
Kok Hong Tan Fang Sheng Lim Alfred Zhen Yang Toh Xia‐Xi Zheng Chang Fu Dee Burhanuddin Yeop Majlis Siang‐Piao Chai Wei Sea Chang 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(20)
Observation of visible light trapping in zinc oxide (ZnO) nanorods (NRs) correlated to the optical and photoelectrochemical properties is reported. In this study, ZnO NR diameter and c‐axis length respond primarily at two different regions, UV and visible light, respectively. ZnO NR diameter exhibits UV absorption where large ZnO NR diameter area increases light absorption ability leading to high efficient electron–hole pair separation. On the other hand, ZnO NR c‐axis length has a dominant effect in visible light resulting from a multiphoton absorption mechanism due to light reflection and trapping behavior in the free space between adjacent ZnO NRs. Furthermore, oxygen vacancies and defects in ZnO NRs are associated with the broad visible emission band of different energy levels also highlighting the possibility of the multiphoton absorption mechanism. It is demonstrated that the minimum average of ZnO NR c‐axis length must satisfy the linear regression model of Z p,min = 6.31d to initiate the multiphoton absorption mechanism under visible light. This work indicates the broadening of absorption spectrum from UV to visible light region by incorporating a controllable diameter and c‐axis length on vertically aligned ZnO NRs, which is important in optimizing the design and functionality of electronic devices based on light absorption mechanism. 相似文献
80.
Harianto Rahardjo Nguyen Cong Thang Yongmin Kim Eng-Choon Leong 《Soils and Foundations》2018,58(3):534-546
Transient process of water flow changes the equilibrium conditions of an unsaturated soil, resulting in volume change of a soil. The volume change alters the hydraulic properties of the soil and thus influences the transient process of water flow through the soil. Therefore, the interactive processes between stress-strain behavior and pore-water pressure are the primary processes affecting the mechanical behavior of unsaturated soils. This paper presents coupled elasto-plastic constitutive equations for unsaturated compacted kaolin under consolidated drained and shearing-infiltration conditions. The study focused on the development of the suction increase (SI) yield curve that incorporates changes in matric suction during transient processes. In addition, the relationship of change in specific water volume with respect to net mean stress and matric suction was also proposed by incorporating the hysteresis of soil-water characteristic curve. The simulated results by the proposed constitutive model were compared with those obtained from isotropically consolidated drained tests and shearing infiltration tests of compacted kaolin to verify the proposed model. The simulated results are in close agreement with the experimental results. 相似文献