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101.
Phase behavior and crystal morphology in poly(ethylene succinate) biodegradably modified with tannin
Siti Nurkhamidah Eamor M. Woo I-Han Huang Chean C. Su 《Colloid and polymer science》2011,289(14):1563-1578
Specific interactions, growth kinetics, and dendritic morphology in poly(ethylene succinate) (PESu) biodegradably modified
with various contents of tannic acid (TA) were characterized using differential scanning analysis, Fourier-transform infrared
(FTIR) spectroscopy, polarized-light optical microscopy, and atomic force microscopy. Strong interactions and highly retarded
growth between PESu and a macromolecular ester with polyphenol groups, TA, interaction-induced highly retarded growth rates
for the PESu/TA (80:20) composition are proven to lead to single-crystal-like dendrites when crystallized at high crystallization
temperature (T
c). At T
c = 70 °C, the growth rate for neat PESu is 12 μm/min while it is dramatically depressed to one tenth-fold at 1.5 μm/min with
20 wt.% TA in the blend. Strong specific interactions between the carbonyl group of polyesters and the phenolic hydroxyl group
of TA are confirmed by (1) the blend’s glass transition temperature (T
g)–composition relationship exhibits a sigmoidal curve, well fitted by the Kwei T
g model for miscible blends with large negative q = −90; (2) thermal analysis on crystal melting revealed an interaction parameter χ = −0.64 between PESu and TA; and (3) IR peak shifting analyzed using two-dimensional FTIR technique. A comparative blend
of another polyester poly(hexamethylene sebacate) with TA, lacking the specific interactions, does not exhibit such single
crystals upon similar melt crystallization. 相似文献
102.
Siti Machmudah Motonobu Goto Wahyudiono Yutaka Kuwahara Mitsuru Sasaki 《Research on Chemical Intermediates》2011,37(2-5):515-522
Nanosecond pulsed laser ablation (PLA) of gold plate with an excitation wavelength of 532?nm was carried out in supercritical CO2 (scCO2) to fabricate gold nanoparticles. Surface morphology of the gold plate after irradiation and the crater depth after PLA were observed by scanning electron microscopy and laser scanning microscopy, while extinction spectra of gold nanoparticles collected in the glass slide was measured by UV?CVis spectrophotometer. The gold plate was ablated at various scCO2 densities and irradiation times at constant temperature of 40??C. The ablation was also conducted at atmospheric condition with air to evaluate the environmental dependence of ablation. Both surface morphology of the irradiated gold plate and crater depth formation were significantly affected by the changes in scCO2 density, the surrounding environment, and irradiation time. As expected, the increasing scCO2 density resulted in a deeper ablation crater, however, the deepest crater was obtained at a density of 0.63?g/cm3 or pressure of 10?MPa. Gold nanoparticles generated by PLA in scCO2 have been confirmed at the spectra band near 530?nm. 相似文献
103.
Siti Sarah Abdul Rahman Daisuke Kawaguchi Daisaku Ito Atsushi Takano Yushu Matsushita 《Journal of Polymer Science.Polymer Physics》2009,47(22):2272-2280
The phase behavior of statistical copolymers composed of (4‐tert‐butylstyrene) (B) and (4‐tert‐butoxystyrene) (O), abbreviated as s‐BO, with polyisoprene (I) was investigated by optical microscopic (OM) observation and small‐angle neutron scattering (SANS) measurements. It has been known that B/I blend shows lower critical solution temperature (LCST) type phase diagram, while O/I blend has upper critical solution temperature (UCST) type one. Several blends of s‐BOs having mol fraction of B, mB, comparable to 0.50, with I showed both UCST and LCST type phase diagram. Furthermore, UCST type phase behavior was observed for blends having small mB, while LCST type one was for that of large mB at all used temperatures. Hence, the phase behavior of s‐BO/I blend can be understood as a result of the competition of two interactions having opposite temperature dependence. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 2272–2280, 2009 相似文献
104.
Siti Zulaikha Mohd Jamaludin Mohd Shareduwan Mohd Kasihmuddin Ahmad Izani Md Ismail Mohd. Asyraf Mansor Md Faisal Md Basir 《Entropy (Basel, Switzerland)》2021,23(1)
An effective recruitment evaluation plays an important role in the success of companies, industries and institutions. In order to obtain insight on the relationship between factors contributing to systematic recruitment, the artificial neural network and logic mining approach can be adopted as a data extraction model. In this work, an energy based k satisfiability reverse analysis incorporating a Hopfield neural network is proposed to extract the relationship between the factors in an electronic (E) recruitment data set. The attributes of E recruitment data set are represented in the form of k satisfiability logical representation. We proposed the logical representation to 2-satisfiability and 3-satisfiability representation, which are regarded as a systematic logical representation. The E recruitment data set is obtained from an insurance agency in Malaysia, with the aim of extracting the relationship of dominant attributes that contribute to positive recruitment among the potential candidates. Thus, our approach is evaluated according to correctness, robustness and accuracy of the induced logic obtained, corresponding to the E recruitment data. According to the experimental simulations with different number of neurons, the findings indicated the effectiveness and robustness of energy based k satisfiability reverse analysis with Hopfield neural network in extracting the dominant attributes toward positive recruitment in the insurance agency in Malaysia. 相似文献
105.
Siti Aminah Omar Thahira B. S. A. Ravoof M. Ibrahim M. Tahir K. A. Crouse 《Transition Metal Chemistry》2014,39(1):119-126
Four new Schiff bases containing N and S heteroatoms (HL1–HL4) have been prepared and characterized, including determination of the X-ray crystal structures of HL1 and HL3. Spectroscopic evidence indicates that these Schiff bases behave as uninegatively charged tridentate NNS ligands in complexes of general formula [Cu(Ln)sac] (Ln is the anionic form of NNS, and sac represents saccharinate anion). Crystals of both HL1 and [Cu(L4)sac)(H2O)]·Hsac crystallized in triclinic system with P $ \bar{1} $ space group, while HL3 crystallized in monoclinic system with P 21/c space group. [Cu(L4)sac)(H2O)]·Hsac has a distorted square-pyramidal structure with a non-bonded saccharin molecule present in the outer coordination sphere. The tridentate NNS ligands are coordinated to Cu through pyridine nitrogen, azomethine nitrogen and thiolate sulfur atoms, while the fourth and fifth coordination positions are occupied by the N-bonded saccharinate anion and a water ligand, respectively. 相似文献
106.
Siti Nooraya Mohd Tawil Rina Kakimi Daivasigamani Krishnamurthy Shuichi Emura Hiroyuki Tambo Shigehiko Hasegawa Hajime Asahi 《固体物理学:研究快报》2010,4(11):308-310
Gd‐doped InGaN layers were prepared by plasma‐assisted molecular‐beam epitaxy in search of new functional diluted magnetic semiconductors for their potential use in spintronics. The local structure around the Gd atoms was examined by the Gd LIII‐edge of X‐ray absorption fine structure. It was found that the majority of Gd atoms substitutionally occupied the cation sites in the InGaGdN layers. Clear hysteresis and saturation magnetization were observed from the magnetization versus field curves examined by means of a superconducting quantum interference device magnetometer at low and room temperatures. In addition, the incorporation of extra shallow donors by co‐doping InGaN with both Gd and Si showed higher magnetization than the undoped InGaGdN. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
107.
Hua Nong Ting See Yan Chia Badrulzaman Abdul Hamid Siti Zamratol-Mai Sarah Mukari 《Journal of voice》2011,25(6):e305
The acoustic characteristics of sustained vowel have been widely investigated across various languages and ethnic groups. These acoustic measures, including fundamental frequency (F0), jitter (Jitt), relative average perturbation (RAP), five-point period perturbation quotient (PPQ5), shimmer (Shim), and 11-point amplitude perturbation quotient (APQ11) are not well established for Malaysian Malay young adults. This article studies the acoustic measures of Malaysian Malay adults using acoustical analysis. The study analyzed six sustained Malay vowels of 60 normal native Malaysian Malay adults with a mean of 21.19 years. The F0 values of Malaysian Malay males and females were reported as 134.85 ± 18.54 and 238.27 ± 24.06 Hz, respectively. Malaysian Malay females had significantly higher F0 than that of males for all the vowels. However, no significant differences were observed between the genders for the perturbation measures in all the vowels, except RAP in /e/. No significant F0 differences between the vowels were observed. Significant differences between the vowels were reported for all perturbation measures in Malaysian Malay males. As for Malaysian Malay females, significant differences between the vowels were reported for Shim and APQ11. Multiethnic comparisons indicate that F0 varies between Malaysian Malay and other ethnic groups. However, the perturbation measures cannot be directly compared, where the measures vary significantly across different speech analysis softwares. 相似文献
108.
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
109.
A series of (E)-1-(4-alkyloxyphenyl)-3-(hydroxyphenyl)-prop-2-en-1-one have been successfully synthesised via Claisen-Schmidt condensation. The synthesised chalcone derivatives consisted of hydroxyl groups at either ortho, meta or para position and differed in the length of the alkyl groups, C (n) H(2) (n) (+1,) where n?=?6, 10, 12 and 14. The structures of all compounds were defined by elemental analysis, IR, (1)H- and (13)C-NMR. The antimicrobial studies were carried out against wild-type Escherichia coli American Type Culture Collection 8739 to evaluate the effect of the hydroxyl and the alkyl groups of the synthesised chalcones. All the synthesised compounds have shown significant antimicrobial activities. The optimum inhibition was dependent on the position of the hydroxyl group as well as the length of the alkyl chains. 相似文献
110.
Y. Abu Muhanna Rosihan M. Ali Zhen Chuan Ng Siti Farah M. Hasni 《Journal of Mathematical Analysis and Applications》2014
The class consisting of analytic functions f in the unit disk satisfying f+αzf′+γz2f″ subordinated to some function h is considered. The Bohr radius for this class is obtained when h is respectively convex or starlike. The Bohr radius for analytic functions mapping the unit disk into a concave-wedge domain as well as for bounded harmonic mappings are also established. 相似文献