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921.
This article introduces the relationship between chemistry and fish farming, fish selling, and fish food. The nitrogen cycle process in fish ponds is introduced to explain the fish farming. "Yufuling" is used as the entry point to fish selling to connect food safety with chemistry. Fishy smell is explained from a chemical perspective for fish food. This paper aims at making a scientific explanation of life phenomena, deepening the consciousness of chemical life, helping people establish a correct view of chemical science, and inspiring youth to learn to use the knowledge that they have learned to explain life phenomena. This paper also tries to show the youth that life cannot be separated from chemistry, and chemistry cannot be separated from life. 相似文献
922.
Yoshida H. Yang M. Masaka K. Houshito Y. Mashiko K. Nakamura S. 《Journal of Thermal Analysis and Calorimetry》2002,70(3):703-711
Phase transition behavior of polyesters derived from 2,7-phenanthrene dicarbonic acid diethylester and alkanediols with even
methylene carbon number was investigated by the simultaneous DSC-XRD method. The smectic A phase was observed on cooling from
the molten state. The transition entropy from the isotropic state to the smectic A phase was about 9.0 J mol-1 K-1, which depended on the methylene carbon number. The linear expansion coefficients, based on the (001) spacing of the crystalline
phase at room temperature, were 1.3·10-4 K-1 (crystalline phase), 5.7·10-4 K-1 (crystallization region), 1.7·10-3 K-1 (smectic A phase) during cooling, and 1.5·10-4 K-1 (crystalline phase), and 1.0·10-3K-1(melting region) on heating.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
923.
Amino‐alcohol derivatives of fragrant, volatile aldehydes and ketones were synthesized in a one‐pot procedure by sequential cyanohydrin formation with trimethylsilyl cyanide and reduction with lithium aluminium hydride, or by ammonolysis of epoxide precursors. The amino alcohols are nonvolatile, stable properfumes releasing fragrant carbonyls by oxidation with sodium periodate or sodium bismuthate. Examples include amino alcohol properfumes of citronellal, Lilial®, lauryl aldehyde, menthone, benzaldehyde, and anisaldehyde. 相似文献
924.
Ju Wang Zuo Yin Yang Xiu Li Wang Jing Chang Zhang Wei Liang Cao State Key Laboratory of Chemical Resource Engineering Faculty of Science Beijing University of Chemical Technology Beijing China 《中国化学快报》2007,18(2):244-246
The conformational conversion of 1,3-dioxane guest encapsulated inside a cylindrical capsular host was investigated with PM3 method and single point energies were evaluated by B3LYP method. When entrapped in the capsule, the guest tumbles were slower than that in the free condition. The influences of the inner phase of the capsule on the guest conformational conversion were discussed in detail. 相似文献
925.
Based on the unique absorbent characters and three-dimensional network structure of polyacrylamide (PAM) superabsorbent polymer, a photocatalytic degradable TiO2/PAM composite was synthesized by an aqueous solution polymerization method with N,N′-methylene bisacrylamide as crosslinker, potassium peroxydisulfate as initiator, acrylamide as monomer, and TiO2 (P-25) as functional filler. The photocatalytic degradability of the composite was evaluated using methyl orange as photodegradation target, and the recovery and reproducibility of the composite was investigated. It was found that TiO2/PAM composite had a good photocatalytic degradability, the composite also possessed a good reproducibility of photocatalytic degradability, which is possible to be used in practical process. 相似文献
926.
Ying-Tong Di Hong-Ping He Zhi-Zhi Du Xian-Wen Yang Xiao-Jiang Hao 《Tetrahedron letters》2006,47(30):5329-5331
A novel Daphniphyllum alkaloid with a rearranged fused-hexacyclic ring system, calycilactone A, was isolated from the leaves of Daphniphyllum calycillum (Daphniphyllaceae), and the structure and relative stereochemistry of the new compound were elucidated on the basis of spectroscopic data. 相似文献
927.
比值光谱导数法同时测定铝合金中铁,铜,锌 总被引:6,自引:0,他引:6
用比值光谱-导数分光光度法,在pH5.5缓冲溶液中,利用金属-2-(5-溴-2-吡啶偶氮)-5-二乙氨基酚(5-Br-PADAP)-OP三元络合物显色体系,对混合物中铁,铜,锌三组分进行了同时测定。合成试样5次测定回收率在97.3%-104.4%之间。应用于铝合金中铁,铜,锌的测定,各6次测定的RSD分别为3.66%,1.38%,2.03%。 相似文献
928.
Stable monolayers of electropolymerized poly-N-vinylcarbazole (EPVK) and arachidic acid(AA) are obtained on a subphase of alkaline Tl2O3 colloidal solutions. As revealed by the atomic force microscope, there is phase separation in the mixed LB monolayers. Transmission electron microscopic observations reveal that ordered arrays of composite Tl2O3/Epvk nanowires are formed in the mixed monolayers. Formation of the composite nanowire arrays is attributed to the ordered adsorption of Tl2O3 colloidal particles along the polycationic EPVK chains. The composite nanowire array is 3.2nm wide with a spacing of 2.7nm.The composite nanowire arrays can also be formed when pure EPVK is used. Composite LB multilayers of Tl2O3/EPVK nanowire arrays are prepared. The bilayer spacing is 5.54nm.The present study is of importance to the fabrication of inorganic semiconductor/functional polymer composite nanowires. 相似文献
929.
Reactions of o-methyl- and o-ethylbenzenediazonium tetrafluoroborates with two equivalents of potassium acetate and five mole percent of 18-crown-6 in ethanol-free chloroform produce indazoles in good to excellent yields. Indazoles bearing either electron-withdrawing or electron-donating substituents may be prepared. 相似文献
930.
α-异丙基、β-异丁基丙烯酸希土配合物的合成和配位性质研究 总被引:3,自引:0,他引:3
本文制备了α-异丙基、β-异丁基丙烯酸的15种希土配合物RE(C9H17COO)3,用X射线多晶粉末衍射、电子光谱、红外光谱和热重差热分析方法研究了配合物中RE-O键的成键性能以及羧基的配位性质.配合物中存在两种不同的羧基配位形式,轻中希土配合物(La,Ce,Pr,Nd,Sm,Eu)中羧基具有不对称桥式双齿配位形式,而重希土配合物(Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu,Y)中羧基具有对称螯合双齿配位形式,配位形式的不同使得希土配合物呈现两种不同的多晶衍射图和热分解过程. 相似文献