Electrochemical reduction of graphene oxide and its electrochemical capacitive performance

A convenient method for the production of graphene is developed using the electrochemical reduction of graphite oxide (GO) in solution without assembling it onto the electrode. The samples were examined by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy. The results show that the number of oxygen functional groups can be significantly decreased. The electrochemical capacitance of the prepared graphene after 8 h of reduction is 158.5 F g^?1 at 0.5 A g^?1, much higher than that of GO and carbon nanotubes. The mechanism for this reaction is also proposed in this paper.     

4760例孕中期产前筛查和产前诊断产妇随访结果分析

目的:探讨孕中期产前筛查和产前诊断在临床中的应用和意义。方法:应用时间分辨法,以血清AFP、β-HCG作为指标,对4 760例在孕15～20+6周孕妇进行产前筛查,对筛查为高风险的孕妇进行一对一的遗传咨询和产前诊断,并在产后3月内对其分娩结局进行随访观察。结果:随访中发现有不同程度畸形、流产、死胎等不良妊娠共29例:高风险者6例,低风险者23例。其中羊水染色体异常2例、超声检查检出各种畸形(开放性神经管畸形如脊柱裂、小头畸形、脑膨出等)6例、内脏畸形(如先心病、肾发育不良、胎儿宫内发育异常等)5例。不明原因死胎、晚期流产3例,21-三体新生儿1例(产前筛查唐氏高风险而拒绝羊水穿刺细胞学检查所致)。结论:孕中期产前筛查和产前诊断可降低出生缺陷的发生。     

银木和樟树遗传多样性与亲缘关系的RAPD分析

利用RAPD技术分析银木和樟树的遗传多样性与亲缘关系.用筛选出的12条引物从7株银木和7株樟树中共扩增得到91条DNA带,其中多态性条带48条,多态性条带比率为52.7%.根据Nei-Li方法进行的遗传相似性分析表明,银木植株间的遗传相似性系数在0.457～0.781,平均为0.564;樟树植株间的遗传相似性系数在0.646～0.862,平均为0.777;银木与樟树间的遗传相似性系数在0.318～0.531,平均为0.422.根据RAPD结果进行的聚类分析正确地将银木与樟树各聚为一类.这些数据说明银木植株间的遗传多样性大于樟树植株间的遗传多样性,银木与樟树之间的亲缘关系小于两种植物内部个体间的亲缘关系.     

"Thiol-ene" click chemistry: a facile and versatile route for the functionalization of porous polymer monoliths

The preparation of porous polymer monoliths with dodecyl and zwitterionic functionalities via the "thiol-ene" click chemistry of thiol-containing monoliths with both hydrophobic and polar methacrylate "ene" monomers has been demonstrated. Selected separations confirmed the excellent potential of these monoliths in chromatography.     

Conversion of carbohydrates into 5-hydroxymethylfurfural catalyzed by ZnCl2 in water

The incompletely coordinated zinc ions in the concentrated aqueous ZnCl(2) solution catalyze the direct conversion of carbohydrates into 5-hydroxymethylfurfural, and a moderate HMF yield up to 50% can be achieved.     

Local well-posedness of a new integrable equation

In this article we focus on the local-in-time well-posedness of the Cauchy problem for a new integrable equation. We proved the local-in-time existence and uniqueness of the entropy solutions by using the method of the vanishing viscosity and L¹$L^1$-contraction property.     

A Novel Route to Prepare Highly Reactive and Versatile Chromatographic Monoliths

The copolymer poly(isocyanatoethyl methacrylate‐co‐methyl methacrylate‐co‐ethylene glycol dimethacrylate) (poly(IEM‐co‐MMA‐co‐EGDMA)) was developed as a novel, facile, highly reactive and versatile monolithic matrix, which was amenable to surface functionalization with a variety of nucleophilic modifiers based on the reactive isocyanate group, producing monoliths of various chemistries suitable for chromatography. The specific surface area, pore size distribution, porosity and morphology of the monolithic matrix were characterized using a mercury intrusion porosimeter and scanning electron microscopy (SEM), respectively. Thermal analysis results revealed that the monolith was thermally stable up to 307 °C. The success of the chemical modification of the monolithic matrix was confirmed by FT‐IR, solid state ¹³C NMR and XPS elemental analysis, showing the high ligand density of the modified monoliths. A ligand density of up to 2.33 mmol·mL⁻¹ was obtained for the 1‐octanol modified monolith (M1) with an isocyanate group conversion of 96.9%, indicating a high efficiency of the modification reaction. The potential application of the monoliths was demonstrated by the separation of a series of compounds. The novel monolithic columns exhibited high mechanical stability, column efficiency and good repeatability and reproducibility.

     

Erbium-doped photonic crystal fiber laser with 49 mW

We have demonstrated a continuous-wave (CW) all fiber laser operation at 1558.4 nm of a diode-pumped erbium-doped PCF laser based on 9.6 m erbium-doped PCF. The maximum output power and the threshold of the fiber laser are 49.4 mW and 6.67 mW, respectively. We show that it is possible to achieve a high stability and beam quality laser, which has a great application potential in optical communication field in future.     

On Water: Free Catalysis Approach for the Synthesis of Nitrones from Hydroxamic Acids and Dimethy/Diethyl Acetylenedicarboxylate

Benzohydroxamic acid reacts with dimethyl acetylenedicarboxylate in the presence of 10 mol% NaOAc to generate (E)‐N‐(1,4‐dimethoxy‐1,4‐dioxobutan‐2‐ylidene)‐1‐phenylcarboxamide oxide in good‐to‐excellent yield in water at room temperature for 2 h, which supplies a simple, efficient and environmentally friendly method to synthesize a wide range of nitrones. The benefits of this strategy not only conform to the requirment of green chemisty, but also possess atom economy.     

河南省野生荷花资源的现状与保护

通过对河南省野生荷花资源的调查研究,初步了解了河南省野生荷花资源的现状:野生荷花资源主要分布在黄河、淮河水系沿岸的湿地、水库以及古河道,生长环境恶劣,大部分处于无人看管甚至遭到人为破坏的状态.而聚类结果显示,野生荷花资源居群之间出现遗传分化现象.针对此现状,从就地保护、迁地保护、种质基因库的建立3个方面探讨了对野生荷花...