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排序方式: 共有1223条查询结果,搜索用时 15 毫秒
961.
Wei Ling Tham Beng Teik Poh Zainal Arifin Mohd Ishak Wen Shyang Chow 《Journal of Thermal Analysis and Calorimetry》2014,118(3):1639-1647
Poly(lactic acid)/halloysite nanotubes (PLA/HNTs) nanocomposites were prepared using melt compounding followed by compression molding. N,N′-ethylenebis(stearamide) (EBS) was used to improve the dispersion of HNTs and toughen the PLA nanocomposites. The thermal properties of PLA/HNTs nanocomposites were assessed by using differential scanning calorimeter and thermogravimetric analyzer (TG). The TG measurements were performed at both nitrogen and oxygen atmosphere. The mechanical properties of PLA/HNTs were characterized through tensile and impact tests. The morphological properties of the PLA/HNTs nanocomposites were investigated by using transmission electron microscopy and field emission scanning electron microscopy. The degree of crystallinity of PLA nanocomposites was increased slightly by the addition of EBS. The decomposition process of PLA/HNTs depends on the atmosphere reaction during TG test as well as the amount of EBS. The best mechanical properties of PLA/HNTs nanocomposites expressed by the impact strength and elongation at break were achieved by the addition of 5 mass% of EBS. 相似文献
962.
Yusuke Hirasawa Yuri Kato Chin Piow Wong Nahoko Uchiyama Yukihiro Goda A. Hamid A. Hadi Hapipah Mohd Ali Hiroshi Morita 《Tetrahedron letters》2014
A novel C16N2-type Lycopodium alkaloid consisting of a quinolizidine with a 6-dimethylaminohexyl side chain, hupermine A (1), was isolated from the club moss of Huperzia phlegmaria, and the structure and relative stereochemistry were elucidated on the basis of spectroscopic data. 相似文献
963.
Mohd Rafein Zakaria Shinji Fujimoto Satoshi Hirata Mohd Ali Hassan 《Applied biochemistry and biotechnology》2014,173(7):1778-1789
Oil palm biomass, namely empty fruit bunch and frond fiber, were pretreated using a planetary ball mill. Particle sizes and crystallinity index values of the oil palm biomass were significantly reduced with extended ball mill processing time. The treatment efficiency was evaluated by the generation of glucose, xylose, and total sugar conversion yields from the pretreatment process compared to the amount of sugars from raw materials. Glucose and xylose contents were determined using high-performance liquid chromatography. An increasing trend in glucose and xylose yield as well as total sugar conversion yield was observed with decreasing particle size and crystallinity index. Oil palm frond fiber exhibited the best material yields using ball milling pretreatment with generated glucose, xylose, and total sugar conversion yields of 87.0, 81.6, and 85.4 %, respectively. In contrast, oil palm empty fruit bunch afforded glucose and xylose of 70.0 and 82.3 %, respectively. The results obtained in this study showed that ball mill-treated oil palm biomass is a suitable pretreatment method for high conversion of glucose and xylose. 相似文献
964.
Synthesis and Characterization of Naphthalene‐Based Banana‐Shaped Liquid Crystals for Photoswitching Properties 下载免费PDF全文
Md Lutfor Rahman Mashitah Mohd Yusoff Gurumurthy Hegde Muhammad Nor Fazli Abdul Malek Nurlin Abu Samah H. T. Srinivasa Sandeep Kumar 《中国化学会会志》2014,61(5):571-577
A series of banana‐shaped monomers containing naphthalene as central units, azobenzene in side arms with terminal alkenes were synthesized and characterized. Polarizing optical microscopy, DSC and X‐ray diffraction measurements reveal that one compound processes a nematic phase while other four compounds exhibit B6 phase. The absorption spectrum of trans‐azobenzene displays high‐intensity π‐π* transition at 365 and low‐intensity n‐π* transition at 450 nm. These molecules exhibit strong photoisomerisation behaviour in solutions in which trans to cis isomerisation takes 55 seconds whereas reverse process takes about 32 hours. Such a long thermal back relaxation is useful for creation of optical image storage devices. 相似文献
965.
Schacher FH Elbert J Patra SK Yusoff SF Winnik MA Manners I 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(2):517-525
We demonstrate the synthesis and characterization of star‐shaped crystalline‐coil block copolymers with four arms consisting of an inner block of poly(ethylene oxide) and an outer semicrystalline compartment of poly(ferrocenyldimethylsilane), [PEO50‐b‐PFDMS35]4. The materials were synthesized by transition‐metal‐catalyzed ring‐opening polymerization of dimethylsila[1]ferrocenophane in the presence of silane‐functionalized four‐arm PEO stars as macroinitiators and they exhibited a moderate polydispersity (PDI?1.4). Self‐assembly in mixtures of THF and different alcohols as selective solvents for the PEO block resulted in the formation of semicrystalline vesicles (ethanol, 1‐butanol) or large, rather ill‐defined, spherical structures (methanol). Further, both the rate of addition of the selective co‐solvent and the overall solvent/non‐solvent ratio drastically affected the size and stability of the self‐assembled particles. We could also show that a photoacid generator, as a model for an active substance, can be encapsulated and the UV‐induced generation of HCl resulted in a straightforward degradation of the organometallic vesicles. 相似文献
966.
M.N.A. Mohd Norddin A.F. Ismail D. Rana T. Matsuura A. Mustafa A. Tabe-Mohammadi 《Journal of membrane science》2008
Modification of sulfonated poly(ether ether ketone) (SPEEK) membrane was attempted by blending charged surface modifying macromolecule (cSMM). The modified membrane was tested for direct methanol fuel cell (DMFC) application; i.e. a SPEEK/cSMM blend membrane was compared to a SPEEK membrane and a Nafion 112 membrane for the thermal and mechanical stability, methanol permeability, and proton conductivity. Thermal and mechanical stability of the blended membrane were slightly reduced from the SPEEK membrane but still higher than the Nafion 112 membrane. The blend membrane was found to be promising for DMFC applications because of its lower methanol diffusivity (2.75 × 10−7 cm2 s−1) and higher proton conductivity (6.4 × 10−3 S cm−1), than the SPEEK membrane. A plausible explanation was given for the favorable effect of cSMM blending. 相似文献
967.
Siddiqi ZA Noor S Shahid M Khalid M 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,78(5):1386-1391
The title complexes were prepared and characterized employing spectral (FAB-Mass, IR, electronic, (1)H and (13)C NMR), thermal and electrochemical techniques. Analytical and FAB-Mass data suggested a homo-dinuclear stoichiometry. IR and electronic ligand field spectral studies coupled with molecular model computations have indicated a distorted octahedral geometry where the ligand coordinates as a hexadentate dianionic [H(3)DTPA](2-)(H(5)DTPA=diethylenetriaminepentaacetic acid) moiety. The electrochemical redox properties and the antibacterial activities of the compounds were also investigated. 相似文献
968.
969.
In many applied disciplines like computer science, coding theory and formal languages, the use of fuzzified algebraic structures especially ordered semigroups play a remarkable role. In this paper, we introduce a new concept of fuzzy Γ-ideal of an ordered Γ-semigroup G called an (∈, ∈ ?q k )-fuzzy Γ-ideal of G. Fuzzy Γ-ideal of type (∈, ∈ ∨q k ) are the generalization of ordinary fuzzy Γ-ideals of an ordered Γ-semigroup G. A new characterization of ordered Γ-semigroups in terms of an (∈, ∈ ∨q k )-fuzzy Γ-ideal is given. We show that a fuzzy subset λ of an ordered Γ-semigroup G is an (∈, ∈ ∨q k )-fuzzy Γ-ideal of G if and only if U (λ; t) is a Γ-ideal of G for all \(t \in \left( {0,\frac{{1 - k}} {2}} \right]\) . We also investigate some important characterization theorems in terms of this notion. Finally, regular ordered Γ-semigroups are characterized by the properties of their (∈, ∈ ∨q k )-fuzzy Γ-ideals. 相似文献
970.
For α 0, λ 0 and β,η∈R, we consider the M(α,λ)_b of normalized analyticα—λ convex functions defined in the open unit disc U. In this paper we investigate the class M(α, λ,β,η)_b,with f_b := z/(1-z~n)~b being Koebe type. By making use of Jack's Lemma as well as several differential and other inequalities, the authors derive sufficient conditions for starlikeness of the class M(α, λ, β, η)_b of n-fold symmetric analytic functions of Koebe type. Relevant connections of the results presented here with those given in earlier works are also indicated. 相似文献