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1.
Yingyot Poo‐arporn Surachai Thachepan Rungtiva Palangsuntikul 《Journal of synchrotron radiation》2015,22(1):86-90
Evidence of internal sulfate attack in field exposure was demonstrated by the damaged interior wall of a three‐year‐old house situated in Nakhon Ratchasima Province, Thailand. Partial distension of the mortar was clearly observed together with an expansion of a black substance. Removal of the black substance revealed a dense black layer. This layer was only found in the vicinity of the damaged area, suggesting that this black material is possibly involved in the wall cracking. By employing synchrotron‐based X‐ray photoelectron spectroscopy (XPS) and X‐ray absorption near‐edge structure (XANES) techniques, the unknown sample was chemically identified. The S 2p and O 1s XPS results mutually indicated the existence of sulfate species in the materials collected from the damaged area. The XANES results indicated the presence of ferrous (II) sulfate, confirming sulfate‐induced expansion and cracking. The sulfate attack in the present case appeared to physically affect the structure whereas the chemical integrity at the molecular level of the calcium silicate hydrate phase was retained since there was a lack of spectroscopic evidence for calcium sulfate. It was speculated that internal sulfate probably originated from the contaminated aggregates used during the construction. The current findings would be beneficial for understanding the sulfate‐attack mechanism as well as for future prevention against sulfate attack during construction. 相似文献
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Sunisa Suwancharoen Orawan Chonvanich Sophon Roengsumran Surachai Pornpakakul 《Chemistry of Natural Compounds》2012,48(4):583-586
A new seco-kaurane type diterpenoid, ent-3,4-seco-17-oxo-kaur-4(19),15(16)-dien-3-oic acid, and a known compound, ent-3,4-seco-kaur-4(19),16(17)-dien-3-oic acid, were isolated from the stem bark of Croton oblongifolius. The structures of these compounds were established on the basis of spectroscopic data. 相似文献
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Research on Chemical Intermediates - In this study, selective formation of 5-ethoxymethylfurfural (EMF) from one-pot conversion of fructose in a co-solvent of ethanol with tetrahydrofuran over... 相似文献
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Surachai Pornpakakul Sophon Roengsumran Amorn Petsom Nattaya Ngamrojnavanich Narongsak Chaichit 《Tetrahedron letters》2007,48(4):651-655
A novel CYP3A4 inhibitor, diaporthichalasin, together with pycnidione were isolated from an endophytic fungus, Diaporthe sp. Their structures were elucidated on the basis of spectral data and the structure of diaporthichalasin was confirmed by X-ray crystallographic analysis. Diaporthichalasin exhibited significantly potent inhibition of CYP3A4 with an IC50 value of 0.626 μM, while the IC50 value of pycnidione was 465 μM. 相似文献
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Vichai Reutrakul Surachai Nimgirawath Sirichai Panichanun Yupayao Srikirin 《Tetrahedron letters》1979,20(15):1321-1322
An efficient one-pot synthesis of α,β-unsaturated ketones via the decarboxylative elimination of sodium glycidates with lead tetraacetate is described. 相似文献
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Research on Chemical Intermediates - The efficient/low-cost activated carbons were prepared from inedible fruits such as Cerbera odollam Gaertn, Terminalia catappa, Ficus lyrata, Couroupita... 相似文献
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Maneechakr Panya Chaturatphattha Phutthiphong Karnjanakom Surachai 《Research on Chemical Intermediates》2018,44(11):7135-7157
Research on Chemical Intermediates - The objective of this work was to prepare a highly efficient adsorbent from Leucaena leucocephala (Lam) de Wit via pyrolysis and chemical activation (H3PO4)... 相似文献
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在水溶液中锡盐与β分子筛金属化过程中很容易水解为氢氧化物,因此,制备高度分散的、以孤立形式存在的锡物种非常具有挑战性.我们先采用SnCl2/氯化胆硷(ChCl)络合物将锡物种固定在高硅的商品化的β分子筛上,然后焙烧就可很方便地在水溶液条件下制得了高度分散于β分子筛上的锡物种.电镜照片、紫外-可见光光谱和X射线衍射结果证实了这一点.ChCl的存在促进了锡物种与分子筛的结合.担载(1-2)wt%Sn的β分子筛在葡萄糖-果糖异构化反应中表现出较高的催化活性和选择性. 相似文献
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Chanatip Samart Surachai Karnjanakom Chaiyan Chaiya Prasert Reubroycharoen Ruengwit Sawangkeaw Metta Charoenpanich 《Arabian Journal of Chemistry》2019,12(8):2028-2036
The experimental parameters for biodiesel production from para rubber seed oil and methanol using a SO3H-MCM-41 catalyst were optimized statistically. The SO3H-MCM-41 catalyst was synthesized by co-condensation in the presence of tetraethyl orthosilicate, 3-mercaptopropyl (methyl) dimethoxysilane (MPMDS) and cetyl-trimethylammonium bromide. In the last step, the solid catalyst (SH-MCM41) was oxidized by H2O2 to SO3H-MCM-41. The acid capacity of the obtained SO3H-MCM-41 catalyst was quantified by back titration with 0.1 M sodium hydroxide. The physical and chemical properties of the SO3H-MCM-41 were characterized by nitrogen adsorption/desorption, X-ray diffractometry, Fourier transform infrared spectroscopy and thermogravimetric analysis. The effect of varying the catalyst loading (wt.%), reaction time (h) and temperature (°C) and molar composition of MPMDS on the biodiesel yield were investigated using a 2k factorial design. The optimal conditions to maximize the biodiesel yield, obtained from the response surface analysis using a Box–Behnken design, was a 14.5 wt.% catalyst loading, and a reaction time and temperature of 48 h and 129.6 °C. Under these conditions a fatty acid methyl ester (biodiesel) yield of 84% was predicted, and an 83.10 ± 0.39% yield experimentally obtained. 相似文献