Theoretical Study on the Intermolecular Interactions between 1,1‐Diamino‐2,2‐Dinitroethylene and H2O

The density functional method was applied to the study of 1,1‐diamino‐2,2‐dinitroethylene (Fox‐7)/H₂O dimer. All the possible dimers ( 1, 2 and 3 ), as well as the monomers, were fully optimized with the DFT method at the B3LYP/6‐311++G^** level. The basis set superposition errors (BSSE) are 4.62, 4.07 and 3.45 kJ/mol, and the zero point energy (ZPE) corrections for the interaction energies are 7.94, 5.66 and 6.40 kJ/mol for 1, 2 and 3 , respectively. Dimer 1 is the most stable, judged by binding energy. After BSSE and ZPE corrections, the greatest corrected intermolecular interaction energy of dimer 1 was predicted to be ?29.36 kJ/mol. The charge redistribution mainly occurs on the adjacent N–H··· O atoms and N–O··· H atoms between submolecules. The oxygen in the nitro group acts as a moderate hydrogen acceptor as compared to water oxygen. Based on the statistical thermodynamic method, the standard thermodynamic functions, heat capacities (C⁰_P), entropies (S⁰_T) and thermal corrections to enthalpy (H⁰_T), and the changes of thermodynamic properties on going from monomer to dimer over the temperature range 200.00‐700.00 K were predicted. It is energetically or thermodynamically favorable for Fox‐7 to bind with H₂O and to form dimer 1 at room temperature.     

单壁纳米碳管的纯化及表征

利用微孔膜及空气氧化法逐步除去电弧放电法制备的单壁纳米碳管(SWCNTs)中的金属催化剂粒子、碳纳米粒子、无定形碳等杂质,并利用热重分析（TGA）、高分辨透射电子显微镜（HRTEM）及拉曼（Raman）光谱,对每一步得到的产物进行分析表征.实验证明,该方法对单壁纳米碳管的纯化是比较有效的,可以得到纯度在90％以上的单壁纳米碳管.     

催化裂解低碳烷烃制备碳纳米管薄膜

碳纳米管性质奇特、用途广泛[1]。目前制备碳纳米管薄膜的方法主要有电弧放电法[2]、催化裂解[3]、及真空过滤碳纳米管悬浮液制备“巴基管纸”(Buckypaper)[4]等。本文采用镀镍基板催化裂解低碳烷烃法制备碳纳米管薄膜,考察了镀膜时间、蚀刻和氨水处理等条件对碳纳米管薄膜产物形貌的影响。1　实验部份1 1　镀膜与后处理采用离子溅射法在硅酸盐基板上镀镍,镀镍电流7 5mA,镀镍时间分别为2min、15min、30min、45min或60min;对镀镍基板再进行蚀刻(蚀刻电流7 5mA,蚀刻时间2min)或用氨水浸泡处理(含NH325%,超声振荡30min),然后烘干备用。1 …     

The application of isotope dilution thermal ionization mass spectrometry to traceability of chemical measurement and interlaboratory comparisons

In this work, the method of isotope dilution thermal ionization mass spectrometry able to trace to SI was developed to accurately measure trace amount of Cd, Pb, Zn and Cu in sediment, rice, wine, and human serum samples for interlaboratory comparisons. The research focuses on how to apply the primary method correctly, uncertainty evaluation of measurement results, and how to achieve the meaning of traceability to SI by using ID-TIMS. As a result, the measurement results of Cu and Zn in the human serum 1 and 2 with 0.94, 0.83 and 0.49% combined uncertainty, respectively, were accepted by EC-JRC-IRMM as the certified values of the serum samples. The measurement results of Cd and Pb in CCQM-K13 and CCQM-K24 with 3.96, 1.62 and 1.03% combined uncertainty, respectively, are within the degrees of the equivalence. These comparisons at the highest level of measurement are proof that traceability of chemical measurement can be achieved as the traceability chain of ID-TIMS established in this work was used.     

创新型化学科普设计与实践——以流行歌曲的化学密码为例

Chemistry is the force to transform nature. To let people have a proper understanding of chemistry, this popular science teaching team, based on the previously Finding Chemistry in Detective Conan, select creatively words from the lyrics of influential pop songs, such as "blue and white porcelain" and "bubble", as the hot problems for chemistry popular science teaching; based on the chemistry topic of each part, seven interactive episodes of popular science are designed, which are rich in content and popular with readers.     

Biotransformation of p‐Coumaric Acid (=(2E)‐3‐(4‐Hydroxyphenyl)prop‐2‐enoic Acid) by Momordica charantia Peroxidase

LC/MS³‐Guided biotransformation of p‐coumaric acid (=(2E)‐3‐(4‐hydroxyphenyl)prop‐2‐enoic acid; CA) with H₂O₂/Momordica charantia peroxidase at pH 5.0 and 45° in the presence of acetone has resulted in the isolation of three CA trimers, triCA1 ( 1 ), triCA2 (trans‐ 2 ), and triCA3 (cis‐ 2 ), and seven CA dimers, diCA1–diCA7, i.e., 3 – 9 , among which seven (triCA1–triCA3 and diCA1–diCA4) are new compounds and three (diCA5–diCA7) are known compounds. The structures were established by 2D‐NMR such as HSQC, HMBC, and NOESY measurements. The possible mechanism for the formation of the products is also discussed (Schemes 1–3). This is the first time that the biotansformation of p‐coumaric acid catalyzed by peroxidase in vitro was achieved. Compounds triCA3 (cis‐ 2 ), diCA1 ( 3 ), diCA5 ( 7 ), and diCA7 ( 9 ) exhibit a stronger antioxidative activity than the parent CA.     

超声波作用下的烯醇硅醚环丙化反应的研究

研究了超声波作用下烯醇硅醚的环丙化反应(Simmons-Smith反应),发现在超声波和CuCl共同作用下,锌粉能有效地被活化。三甲基硅氧基环丙烷类化合物的产率可达56%～78%。同时,还研究了超声波功率、反应温度、溶剂、反应时间等对环丙化反应的影响。     

A Novel Protein Found in Selenium-rich Silkworm Pupas

Selenium(Se)is well known for its cancer-preventive function1.In our previous work,silkworm pupas from Ziyang county of Shanxi Province,one of the two largest Se-rich areas in China,was found to have Se content215times higher than that from Luoyang which is a normal region in China2.Meanwhile,Se-rich amino acids extracted from Ziyang pupas could efficiently induce the apoptosis of human hepatoma cells SMMC-7721.In order to find out the effective component responsible for this carcinostat…     

Fluorescence Quenching of Poly[2-methoxy-5-（2′-ethylhexoxy）-p-phenylene vinylene] （MEH-PPV） in Solutions

Fluorescence quenching processes of poly[2-methoxy-5-(2‘ethyl-hexoxy)-p-phenylene vinylene] (MEH-PPV) in solution by electron acceptors, O2 and acid, have been studied. Static quenching of the fluorescence from MEH-PPV by an electron acceptor (DDQ or TCNE) occurs due to electron transfer from MEH-PPV to the electron acceptor and this electron transfer quenching can be promoted by chloroform. Photooxidation takes place in the MEH-PPV solution and singlet oxygen is an intermediate in the photooxidation, according to the results of ESR spectroscopy. Acid also plays an important role in the fluorescence quenching process of MEH-PPV, by the protonation of the alkoxy groups in the molecular chain.     

Relative rate constants for the reactions of hydroxyl radicals and chlorine atoms with a series of aliphatic alcohols

Rate constants for the gas‐phase reactions of hydroxyl radicals and chlorine atoms with a series of alcohols have been determined by using the relative method. The experiments were performed at 295 ± 2 K and at 1 atmospheric pressure. The obtained values of the rate constants in units of 10^?12 cm³ molecule^?1 s^?1 are as follows: