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排序方式: 共有937条查询结果,搜索用时 15 毫秒
151.
152.
Rahim MA Islam MS Bae TS Choi WS Noh YY Lee HJ 《Langmuir : the ACS journal of surfaces and colloids》2012,28(22):8486-8495
The mixing of Ag ion-doped poly(ethyleneimine) (PEI) and poly(acrylic acid) (PAA) produced Ag ion-doped polyelectrolyte complex particles (PECs) in solution. Positively charged Ag ion-doped PECs (Ag ion PECs) with a spherical shape were deposited alternatively with PAA to form a multilayer assembly. The multilayered film containing Ag ion PECs was reduced to generate a composite nanostructure. Metal nanoparticle (NP)-enriched nanocomposite films were formed by an additional process of the postadsorption of precursors on PECs within the nanocomposite films, which resulted in the enhancement of the catalytic and electrical properties of the composite films. Because the films contain PECs that are responsive to changes in pH and most of the NPs are embedded in the PECs, interesting catalytic properties, which are unexpected in a particle-type catalyst, were observed upon pH changes. As a result of the reversible structural changes of the films and the immobilization of the NPs within the films, the film-type catalysts showed enhanced performance and stability during catalytic reactions under various pH conditions, compared to particle-type catalysts. 相似文献
153.
Yoshinori Namihira Md. Anwar Hossain Taito Koga Md. Ashraful Islam S. M. Abdur Razzak Shubi F. Kaijage Yuki Hirako Hiroki Higa 《Optical Review》2012,19(2):78-81
In this paper, we propose a highly nonlinear dispersion flattened hexagonal photonic crystal fiber (HNDF-HPCF) with nonlinear
coefficients as large as 57.5W−1 km−1 at 1.31 μm wavelength for dental optical coherence tomography (OCT) applications. This HNDF-HPCF offers not only large nonlinear
coefficient but also very flat dispersion slope and very low confinement losses. Using these characteristics of our proposed
PCF, it is shown through simulations by using finite difference method with an anisotropic perfectly matched boundary layer
that this PCF offers the efficient supercontinuum (SC) generation for dental OCT applications at 1.31 μm wavelength using
a picosecond pulse easily produced by commercially available less expensive laser sources. Coherent length of light source
using SC is found 10 μm and the spatial resolutions in the depth direction for dental applications of OCT are found about
6.1 μm for enamel and 6.5 μm for dentin. 相似文献
154.
Abdul Al MortuzaMd. Hafijur Rahman Sinthia Shabnam MouMd. Johurul Islam Abu Bakar Md. Ismail 《Current Applied Physics》2012,12(2):565-569
The structural, electrical and optical characteristics of porous silicon (PS) due to the impregnation of LaF3 into PS by a novel chemical-bath deposition (CBD) technique have been investigated in this article. Without removing the PS from the anodization chamber the impregnation with LaF3 has been done by reacting LaCl3 with HF in the same chamber at room temperature. The impregnation of LaF3 was confirmed by the SEM on the cross-section of the LaF3/PS/Si system and EDX. The modification of PS surface by LaF3 had direct influence on the electrical and optical properties of PS. Electrical properties of Ag/LaF3/PS/p-Si/Ag structures were studied through the current-voltage (I-V) and capacitance-voltage (C-V) characteristics. Formation of metal-insulator-semiconductor (MIS) diode was evident whose forward current increased with annealing. A diode factor of about 2.4 has been obtained for the annealed heterostructure indicating a high density of trap states. The C−2-V curves of all samples showed negative flat band voltage of around −2 V confirming a large number of fixed positive charges in the LaF3. The photoluminescence (PL) intensity of the LaF3-impregnated PS showed aging for the as-deposited samples, but when annealed PS structure recovered the PL intensity. Experimental results show that the optimized chemical bath passivation process for the LaF3 on porous silicon could enable the porous silicon to be an important material for photonic application. 相似文献
155.
Abd Elgadir M Akanda MJ Ferdosh S Mehrnoush A Karim AA Noda T Sarker MZ 《Molecules (Basel, Switzerland)》2012,17(1):584-597
A binary mixture of starch-starch or starch with other biopolymers such as protein and non-starch polysaccharides could provide a new approach in producing starch-based food products. In the context of food processing, a specific adjustment in the rheological properties plays an important role in regulating production processing and optimizing the applicability, stability, and sensory of the final food products. This review examines various biopolymer mixtures based on starch and the influence of their interaction on physicochemical and rheological properties of the starch-based foods. It is evident that the physicochemical and rheological characteristics of the biopolymers mixture are highly dependent on the type of starch and other biopolymers that make them up mixing ratios, mixing procedure and presence of other food ingredients in the mixture. Understanding these properties will lead to improve the formulation of starch-based foods and minimize the need to resort to chemically modified starch. 相似文献
156.
Akanda MJ Sarker MZ Ferdosh S Manap MY Ab Rahman NN Ab Kadir MO 《Molecules (Basel, Switzerland)》2012,17(2):1764-1794
Supercritical fluid extraction (SFE), which has received much interest in its use and further development for industrial applications, is a method that offers some advantages over conventional methods, especially for the palm oil industry. SC-CO? refers to supercritical fluid extraction (SFE) that uses carbon dioxide (CO?) as a solvent which is a nontoxic, inexpensive, nonflammable, and nonpolluting supercritical fluid solvent for the extraction of natural products. Almost 100% oil can be extracted and it is regarded as safe, with organic solvent-free extracts having superior organoleptic profiles. The palm oil industry is one of the major industries in Malaysia that provides a major contribution to the national income. Malaysia is the second largest palm oil and palm kernel oil producer in the World. This paper reviews advances in applications of supercritical carbon dioxide (SC-CO?) extraction of oils from natural sources, in particular palm oil, minor constituents in palm oil, producing fractionated, refined, bleached, and deodorized palm oil, palm kernel oil and purified fatty acid fractions commendable for downstream uses as in toiletries and confectionaries. 相似文献
157.
Dr. Maxence Urbani Dr. Kei Ohkubo Dr. D. M. Shafiqul Islam Prof. Dr. Shunichi Fukuzumi Prof. Dr. Fernando Langa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(24):7473-7485
Donor–bridge–acceptor triad (Por‐2TV‐C60) and tetrad molecules ((Por)2‐2TV‐C60), which incorporated C60 and one or two porphyrin molecules that were covalently linked through a phenylethynyl‐oligothienylenevinylene bridge, were synthesized. Their photodynamics were investigated by fluorescence measurements, and by femto‐ and nanosecond laser flash photolysis. First, photoinduced energy transfer from the porphyrin to the C60 moiety occurred rather than electron transfer, followed by electron transfer from the oligothienylenevinylene to the singlet excited state of the C60 moiety to produce the radical cation of oligothienylenevinylene and the radical anion of C60. Then, back‐electron transfer occurred to afford the triplet excited state of the oligothienylenevinylene moiety rather than the ground state. Thus, the porphyrin units in (Por)‐2TV‐C60 and (Por)2‐2TV‐C60 acted as efficient photosensitizers for the charge separation between oligothienylenevinylene and C60. 相似文献
158.
S.M. Islam Anupam Singha Roy Paramita Mondal Kazi Tuhina Manir Mobarak John Mondal 《Tetrahedron letters》2012,53(2):127-131
A new polymer-anchored Cu(II) complex has been synthesized and characterized. The catalytic performance of the complex has been tested for the oxidation of sulfides and in oxidative bromination reaction with hydrogen peroxide as the oxidant. Sulfides have been selectively oxidized to the corresponding sulfoxides in excellent yields and in the presence of KBr as the bromine source, organic substrates have been selectively converted to mono bromo substituted compounds using polymer-anchored Cu(II) catalyst. This catalyst showed excellent catalytic activity, high selectivity, and recyclability. The polymer-anchored Cu(II) catalyst could be easily recovered by filtration and reused more than five times without appreciable loss of its initial activity. 相似文献
159.
Giovanni Ferrara Tienan Jin Md. Akhtaruzzaman Ashraful Islam Liyuan Han Hua Jiang Yoshinori Yamamoto 《Tetrahedron letters》2012,53(15):1946-1950
A facile, efficient, and general synthetic method for iodo-substituted benzo[b]naphtho[2,1-d]thiophenes has been developed via a cascade cyclization of thioanisole-substituted aryldiynes using iodine. A new donor–π linker–acceptor (D–π–A) organic dye, G1, with the benzo[b]naphtho[2,1-d]thiophene moiety as an electron donor has been synthesized, and the performance of dye-sensitized solar cell based on G1 has been investigated. 相似文献
160.