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排序方式: 共有2214条查询结果,搜索用时 31 毫秒
101.
Yin Fong Yeong Ahmad Zuhairi Abdullah Abdul Latif Ahmad Subhash Bhatia 《Journal of Porous Materials》2011,18(2):147-157
Propylsulfonic acid-functionalized partially crystalline silicalite-1 materials were synthesized via one step co-condensation
technique by varying the molar ratio of organosilane source, 3-mercaptopropyltrimethoxysilane (3MP) to tetraethylorthosilicate
(TEOS) in the range of 0.05–0.30, and subsequent oxidation of thiol group to propylsulfonic acid using hydrogen peroxide (H2O2). These materials were characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM),
scanning electron microscopy (SEM) and nitrogen adsorption–desorption method. The structure of these materials was determined
by Fourier transform infrared spectroscopy (FT-IR) and 29Si and 13C solid state NMR. XRD results show that % crystallinity of the materials decreased with the increase in 3MP concentration
in the synthesis mixture. Selected area electron diffraction (SAED) showed the presence of crystalline and amorphous phases
in the samples. An amorphous phase was formed when 3MP concentration was 30 mol% of the total silica source. After elimination
of the structure directing agent (SDA) by calcination at 420 °C, thermogravimetric analysis (TGA) shows that the structure
was thermally stable up to 550 °C. Ammonia temperature-programmed desorption (NH3-TPD) shows that the acid capacity of these materials was in the range of 1.19–1.83 mmol H+/g, which shows that these materials could be used as potential heterogeneous acid catalyst. 相似文献
102.
103.
Tan Chee Hau Yap Hwa Jen Musa Siti Nurmaya Chang Siow Wee Sivadas Chandra Sekaran Hisaburi Ahmad Syazwan Liew Kan Ern Ismail Ahmad Humaizi Baharudin Luqman Hakim 《Journal of Mechanical Science and Technology》2021,35(9):4115-4123
Journal of Mechanical Science and Technology - Facility layout planning (FLP) has an important role in manufacturing industries. There are few approaches to solve FLP such as procedural,... 相似文献
104.
Investigation on the effect of spinning conditions on the properties of hollow fiber membrane for hemodialysis application 下载免费PDF全文
Sumarni Mansur Mohd Hafiz Dzarfan Othman A. F. Ismail Siti Hamimah Sheikh Abdul Kadir Fatmawati Kamal Pei Sean Goh Hasrinah Hasbullah Bee Cheer Ng Mohd Sohaimi Abdullah 《应用聚合物科学杂志》2016,133(30)
Polyethersulfone (PES) hollow fiber membranes were fabricated via the dry‐wet phase inversion spinning technique, aiming to produce an asymmetric, micro porous ultrafiltration hollow‐fiber specifically for hemodialysis membrane. The objective of this study is to investigate the effect of spinning conditions on the morphological and permeation properties of the fabricated membrane. Among the parameters that were studied in this work are air gap distance, dope extrusion rate, bore fluid flow rate, and the take‐up speed. The contact angle was measured to determine the hydrophilicity of the fibers. Membrane with sufficient hydrophilicity properties is desired for hemodialysis application to avoid fouling and increase its biocompatibility. The influences of the hollow fiber's morphology (i.e., diameter and wall thickness) on the performance of the membranes were evaluated by pure water flux and BSA rejection. The experimental results showed that the dope extrusion rate to bore fluid flow rate ratio should be maintained at 1:1 ratio to produce a perfectly rounded asymmetric hollow fiber membrane. Moreover, the flux of the hollow fiber spun at higher air gap distance had better flux than the one spun at lower air gap distance. Furthermore, spinning asymmetric hollow fiber membranes at high air gap distance helps to produce a thin and porous skin layer, leading to a better flux but a relatively low percentage of rejection for BSA separation. Findings from this study would serve as primary data which will be a useful guide for fabricating a high performance hemodialysis hollow fiber membrane. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43633. 相似文献
105.
Synthesis and Characterization of NiO Nano‐Spheres by Templating on Chitosan as a Green Precursor 下载免费PDF全文
Cheng Keong Choo Tze Lim Goh Ladan Shahcheraghi Gek Cheng Ngoh Ahmad Zuhairi Abdullah Bahman Amini Horri Babak Salamatinia 《Journal of the American Ceramic Society》2016,99(12):3874-3882
In this study, nickel oxide was prepared through the calcination of extrusion dripped chitosan/nickel nitrate beads. The morphology and structural properties of the products were studied using various characterization techniques. Uniformly distributed nickel oxide was formed as observed from the studies of surface morphology where the processing parameters play a huge role on the resulting morphology. TEM results have shown that nickel oxide with crystallite sizes of 10–30 nm was obtained. The Fourier‐transform infrared spectra studies show an intense peak at 525 cm?1, which is attributed to the vibration of Ni–O bond. Furthermore, the XRD results show NiO diffraction peaks correspond to (111), (200), (220), (311), and (222) which indicates that a bunsenite structure with a face‐centered cubic phase was produced in this study. The usage of 500°C as the lower limit in this study is justified due to the complete removal of the templating material as seen in the thermalgravimetric analysis studies. Furthermore, it was obtained that the largest surface area of nickel oxide synthesized using this technique is 48.024 m2/g with pore sizes of 19.843 nm. The usage of chitosan as a green template for the synthesis of nanoparticles has shown promising results which allows a more economical and sustainable approach for the fabrication of nanomaterials. 相似文献
106.
Ahmad A. Adewunmi Suzylawati Ismail Abdullah S. Sultan 《Journal of Inorganic and Organometallic Polymers and Materials》2016,26(4):717-737
Interest in the development of polymeric hydrogels impregnated with carbon-nanotubes (CNTs) is growing rapidly in recent times owing to their usefulness in many fields of human endeavor. This review paper serves as an archive of literature reports of several researchers who have worked on polymeric hydrogels embedded with CNTs for diverse applications. The review covers up to date research advancement on the synthesis and characterization properties of CNTs nanocomposite hydrogels. Besides, this review discusses extensively the various fields in which polymeric hydrogels infused with CNTs have been applied. This unprecedented compilation of CNTs nanocomposite hydrogels information into a single revision allows a straightforward comparison of studies performed for diverse applications. 相似文献
107.
Glass–ceramic materials in the composition (mol%) 23.5 Na2O–23.5CaO–xMgO–xZnO–47SiO2–(6-2x) P2O5 (x = 0 and 1.5) were prepared by the sol–gel technique using sodium metasilicate (Na2SiO3) as source of Na2O and SiO2. Bioactivity was investigated in vitro by examining apatite formation on the surface of the samples after treatment in acellular simulated body fluid (SBF). Formation of bioactive apatite layer on the samples was confirmed by using scanning electron microscope, X-ray diffraction and Fourier transform infrared spectroscopy. Reactivity of the materials in SBF was based on changes in pH and ionic concentration of the solution as a function of immersion duration. Results obtained indicated that the sample doped with Mg and Zn exhibited greater crystallinity containing phases such as CaMgSi2O6, Ca2MgSi2O7, CaSiO3, Na2CaSi3O9, Na2CaSi3O8, CaZnSi2O7 and a new secondary phase, clinohedrite (CaZnSiO4·H2O), while the undoped sample contained a single crystalline phase composed of Na2Ca2Si3O9. After 7 days in SBF, phase transformation occurred at different rates on the materials leading to formation of apatite layer. The result shows that controlled amounts of MgO and ZnO may be useful in tuning up the mechanical properties of bioactive glasses while maintaining bioactivity. 相似文献
108.
Synthesis,Characterization and Surface Properties of Amidosulfobetaine Surfactants Bearing Odd-Number Hydrophobic Tail 下载免费PDF全文
S. M. Shakil Hussain Mustapha Alao Animashaun Muhammad Shahzad Kamal Nisar Ullah Ibnelwaleed A. Hussein Abdullah S. Sultan 《Journal of surfactants and detergents》2016,19(2):413-420
Three amidosulfobetaine surfactants were synthesized namely: 3-(N-pentadecanamidopropyl-N,N-dimethyl ammonium) propanesulfonate (2a); 3-(N-heptadecanamidopropyl-N,N-dimethyl ammonium) propanesulfonate (2b), and 3-(N-nonadecanamidopropyl-N,N-dimethyl ammonium) propanesulfonate (2c). These surfactants were prepared by direct amidation of commercially available fatty acids with 3-(dimethylamino)-1-propylamine and subsequent reaction with 1,3-propanesultone to obtain quaternary ammonium salts. The synthesized surfactants were characterized by IR, NMR and mass spectrometry. Thermogravimetric analysis (TGA) results showed that the synthesized surfactants have excellent thermal stability with no major thermal degradation below 300 °C. The critical micelle concentration (CMC) values of the surfactants 2a and 2b were found to be 2.2 × 10?4 and 1.04 × 10?4 mol/L, and the corresponding surface tension (γCMC) values were 33.14 and 34.89 mN m?1, respectively. The surfactants exhibit excellent surface properties, which are comparable with conventional surfactants. The intrinsic viscosity of surfactant (2b) was studied at various temperatures and concentrations of multi-component brine solution. The plot of natural logarithm of relative viscosity versus surfactant concentration obtained from Higiro et al. model best fit the surfactant behavior. Due to good salt resistance, excellent surface properties and thermal stability, the synthesized surfactant has potential to be used in various oil field applications such as enhanced oil recovery, fracturing, acid diversion, and well stimulation. 相似文献
109.
Zonghua Pu Qian Liu Abdullah M. Asiri Xuping Sun 《Journal of Applied Electrochemistry》2014,44(11):1165-1170
In this communication, we demonstrate the preparation of Ni nanoparticles-graphene hybrid film via simultaneous electrochemical reduction of graphene oxide and Ni2+ on conductive substrate for the first time. We further show the utilization of such hybrid film as an efficient oxygen evolution reaction electrocatalyst with highly catalytic activity and good durability. 相似文献
110.
Akon Higuchi Qing-Dong Ling S. Suresh Kumar Yung Chang Ta-Chun Kao Murugan A. Munusamy Abdullah A. Alarfaj Shih-Tien Hsu Akihiro Umezawa 《Progress in Polymer Science》2014
The physical and chemical characteristics of biomaterial surface and hydrogels can be altered by external stimuli, such as light irradiation, temperature changes, pH shifts, shear stress forces, electrical forces, and the addition of small chemical molecules. Such external stimulus-responsive biomaterials represent promising candidates that have been developed for the culture and differentiation of embryonic stem (ES) cells, induced pluripotent stem (iPS) cells, and adult stem cells. Biomaterials that are designed to respond in a reversible manner to specific external signals can be formed on micropatterned or non-micropatterned surface, in hydrogels, or on microcarriers. Stem cells and the cells differentiated from them into specific tissue lineages can be cultured and/or differentiated on dishes with immobilized external stimulus-responsive polymers. Cells can be detached from these dishes without using an enzymatic digestion method or a mechanical method when the appropriate external stimulus is generated on the surface. This review discusses the polymers and polymeric designs employed to produce surface and hydrogels for stem cell culture, differentiation, and/or cell detachment using various external stimuli. 相似文献