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41.
Prof. Dr. Minghuey Shieh Chun‐Hsien Yu Yen‐Yi Chu Yu‐Wen Guo Chung‐Yi Huang Kai‐Jieah Hsing Pei‐Chi Chen Chung‐Feng Lee 《化学:亚洲杂志》2013,8(5):963-973
The reactions of E powder (E=S, Se) with a mixture of Cr(CO)6 and Mn2(CO)10 in concentrated solutions of KOH/MeOH produced two new mixed Cr? Mn? carbonyl clusters, [E2CrMn2(CO)9]2? (E=S, 1 ; Se, 2 ). Clusters 1 and 2 were isostructural with one another and each displayed a trigonal‐bipyramidal structure, with the CrMn2 triangle axially capped by two μ3‐E atoms. The analogous telluride cluster, [Te2CrMn2(CO)9]2? ( 3 ), was obtained from the ring‐closure of Te2Mn2 ring complex [Te2Mn2Cr2(CO)18]2? ( 4 ). Upon bubbling with CO, clusters 2 and 3 were readily converted into square‐pyramidal clusters, [E2CrMn2(CO)10]2? (E=Se, 5 ; Te, 6 ), accompanied with the cleavage of one Cr? Mn bond. According to SQUID analysis, cluster 6 was paramagnetic, with S=1 at room temperature; however, the Se analogue ( 5 ) was spectroscopically proposed to be diamagnetic, as verified by TD‐DFT calculations. Cluster 6 could be further carbonylated, with cleavage of the Mn? Mn bond to produce a new arachno‐cluster, [Te2CrMn2(CO)11]2? ( 7 ). The formation and structural isomers, as well as electrochemistry and UV/Vis absorption, of these clusters were also elucidated by DFT calculations. 相似文献
42.
A new form of Au3Cu1 hollow nanostructure was prepared by the reaction of Cu nanoparticles with HAuCl4. Following a course of aging, the biomineral botallackite Cu2(OH)3Cl nanoflowers were developed with the aid of Au3Cu1 hollow nanostructures at room temperature. It was proposed that the hollow nanospheres could serve as active centers for heterogeneous nucleation and mediated a mineralization process. Scanning electron microscopy and high-resolution transmission electron microscopy indicated that the nanoflowers are three-dimensional in appearance with a range of 500 nm-- to 1 microm in size and made of several nanopetals with about 25 nm in thickness. In addition, we found that the shape separation could be achieved by using cationic cetyltrimethylammonium bromide to filter the different morphology spherical- and flowerlike structures due to the negative charge of hollow nanospheres. Both hollow nanospheres and nanoflowers presented antimicrobial activity toward Streptococcus aureus with MIC50 at 39.6 and 127.2 microg/mL, respectively. 相似文献
43.
Tzong‐Liu Wang Chien‐Hsin Yang Yeong‐Tarng Shieh An‐Chi Yeh 《Macromolecular rapid communications》2009,30(19):1679-1683
A hybrid inorganic–polymer nanocomposite using CdSe nanocrystals with high electron mobility has been successfully synthesized by atom transfer radical polymerization (ATRP). First the hydroxyl‐coated CdSe nanoparticles (i.e., CdSe–OH) were prepared via a wet chemical route. A polymerization initiator was then prepared for ATRP of N‐vinylcarbazole. FT‐IR, 1H NMR, and XRD analyses confirmed the successful synthesis of CdSe–poly(N‐vinylcarbazole) (PVK) nanohybrid. UV–Vis spectra and photoluminescence data revealed that grafting of PVK onto the surface of CdSe nanocrystals would reduce the band gap of PVK and cause the red shift of emission peak. TEM and SEM micrographs exhibited CdSe nanoparticles that were well‐coated with PVK polymer.
44.
Karl O. Gelotte David N. Mason Harold Meckler Wen-Chung Shieh Colleen M. Starkey 《Journal of heterocyclic chemistry》1990,27(6):1549-1552
An efficient synthesis of the novel triazoloquinazoline adenosine antagonist, CGS 15943, is reported in five steps in approximately 50% overall yield. A key reaction in the synthetic sequence is the double cyclization of an N-(substituted-2-cyanophenyl)carbamate with a carboxylic acid hydrazide to afford a [1,2,4]triazolo-[1,5-c]quinazolin-5(6H)-one in high yield without either a Dimroth or “translocative” rearrangement occurring. Another key reaction is the condensation of a 2-(1H-1,2,4-triazol-5-yl)benzenamine with cyanamide under acidic conditions to prepare a guanidine. 相似文献
45.
Terng-Yin Hsu Bai-Jue Shieh Chen-Yi Lee 《Solid-State Circuits, IEEE Journal of》1999,34(8):1063-1073
A new algorithm for all-digital phase-locked loops (ADPLL) with fast acquisition and large pulling range is presented in this paper. Based on the proposed algorithm, portable cell-based implementations for clock recovery with functions of a frequency synthesizer and on-chip clock generator are completed by standard cell. These modules have been designed and verified on a 0.6-μm CMOS process. Test results are summarized as follows: 1) the proposed ADPLL can satisfy full locked bandwidth and fast acquisition within one data transition; 2) the on-chip clock generator can generate any target clock rate fclock ; and 3) the function of nonreturn-to-zero clock recovery has a maximum fclock/4 recovering capability with a locking range of (τinput±τinput/2)) where τ input is the input period 相似文献
46.
47.
A simple technology for fabricating a short-cavity AlGaAs/GaAs laser with a high-reflective mirror that is compatible with batch processing is described. Chlorine-assisted ion beam etching was used for providing one of the facet reflectors. For increased reflectivity, the etched facet was anodized and then metallized simultaneously with the p-contact metallization step. A threshold current of 8 mA for a six-quantum-well separate confinement structure was achieved with a cavity length of 50 μm 相似文献
48.
We show the first experiment of bit and power loading for coherent optical orthogonal frequency-division-multiplexing (CO-OFDM) systems. The data rate of CO-OFDM systems can be dynamically adjusted according to the channel condition. The system performance can be further improved through optimal power loading into each modulation band. 相似文献
49.
Yeong-Tarng Shieh Hong-Mao Wu Yawo-Kuo Twu Yi-Chang Chung 《Colloid and polymer science》2010,288(4):377-385
The dispersion of carbon nanotubes (CNT) in water of different pH and in chitosan aqueous solution of three acids, acetic
acid, formic acid, and hydrochloric acid, was investigated. Chitosan was soluble in water of pH ≤3 and could well disperse
untreated CNT and acid-treated CNT, both of which had poor dispersion in water of pH ≤3. With the presence of 0.1 wt% chitosan
in solution, particle sizes of the CNT dispersion were found to decrease with increasing COOH contents on the CNT. Particle
sizes of CNT, untreated and acid-treated, in the three acidic aqueous solutions were found to increase with increasing chitosan
contents in solutions. Among the three acids, hydrochloric acid gave the smallest particle size of the CNT dispersion. Without
chitosan, the dispersibility of the acid-treated CNT in aqueous solutions of three acids was in the order of acetic acid >
formic acid > hydrochloric acid. 相似文献
50.
Ming-Der Cheng Alvin R. Caparanga Allan N. Soriano Meng-Hui Li 《The Journal of chemical thermodynamics》2010,42(3):342-347
This report presents a new set of values for the solubility of carbon dioxide in the solvent system {water (1) + monoethanolamine (2) + triethanolamine (3)} at T = (313.2, 333.2, 353.2, and 373.2) K and CO2 partial pressures ranging (1.0 to 120) kPa. The results are specific to solvent systems with the following compositions: (i) ω2 = 0.24, ω3 = 0.06, (ii) ω2 = 0.18, ω3 = 0.12, (iii) ω2 = 0.12, ω3 = 0.18, (iv) ω2 = 0.06, ω3 = 0.24, and (v) ω2 = 0, ω3 = 0.30, where ω refers to the mass fraction of the component. The results fit the Deshmukh and Mather model well. 相似文献