Particle size is a very important factor for the electrochemical performance of materials. However, the effect of the particle size of FePO4 center dot 2H(2)O on the properties of LiFePO4 remains unclear during carbon thermal reduction using FePO4 center dot 2H(2)O as a raw material. Here, LiFePO4/C composites are synthesized by an aqueous rheological phase-assisted carbon thermal reduction method using FePO4 center dot 2H(2)O with different particle sizes as raw materials. The particle size of LiFePO4 is positively correlated with the particle size of FePO4 center dot 2H(2)O. The LiFePO4 materials prepared using small-sized FePO4 center dot 2H(2)O show high purity and small particle size, thus exhibiting an improved rate capacity of 160 mA h g(-1) at 0.1 C and 135 mA h g(-1) at 5 C and cycling stability with a capacity retention of 98.9% after 100 cycles at 2 C. Intriguingly, the LiFePO4 materials prepared using large-sized FePO4 show a longer slope voltage at the end of the discharge curve, which could be accounted for by an Fe3+ phase on the surface of the large-sized LiFePO4. Our studies provide a new understanding of the effect of the particle size of FePO4 center dot 2H(2)O on the properties of LiFePO4 materials during carbon thermal reduction.

分析化学作为本科食品类专业的主要学科基础课程,在该专业学生的化学知识结构中起到了承上启下的作用.成果导向教育(Outcomes-based Education),作为当前高校教育改革发展的趋势,主要是以学生达到设定的学习成果进行教学设计和实施.本文以河南牧业经济学院为例,针对教学过程中所存在的问题,主要围绕教学方法展开,探索将OBE理念贯穿整个授课过程,为社会培养出应用型人才奠定良好的基础.

在应用型高校的食品类专业中,物理化学课程是一座重要的桥梁--连接基础化学和专业课.针对传统单一枯燥的授课方式,我们从课前预习和问题设置、课堂讨论、课后总结和考核形式等方面,探讨了以研讨为主,微课、慕课等多种形式结合的新型教学模式.

介绍了大学生学习能力现状,分析调查了革新晋本科学院大学生的自主学习能力,并提出大学生自主学习能力的培养方案,得出相应的结论.

[目的]建立新的食用油掺伪判别方法,为掺伪食用油的快速鉴定和监管提供支持.[方法]以63份常见的菜籽油、玉米油、大豆油、花生油、棉籽油、葵花籽油、芝麻油、棕榈油等食用油为研究对象,利用已知正品食用油1H NMR谱中各信号峰的积分面积,选取其中2组或3组积分面积制作标准图,建立不同种类正品食用油图谱库,用同样的方法对未知食用油进行测试,将得到的数据代人相应标准食用油图谱进行对比以鉴别是否掺伪.[结果]利用2组积分面积得到的二维图谱能够对食用油的种类进行分类判别;利用3组积分面积制作三维图,能够对掺伪食用油进行准确判别,可准确判别的最低掺伪量为24 mL/L.所建立的判别方法对各种磁场强度的核磁共振波谱仪检测得到的数据均可采用,而且该方法所用软件简单易用、成本较低.[结论]基于1H NMR的掺伪食用油判别方法简单、快捷、经济,值得推广应用.

Fabrication of core-shells on sheets is considered as an effective strategy to explore novel functional composite materials. Herein, a three-component composite was successfully constructed by dispersing and anchoring carbon-coated Fe3O4 nanoparticle core-shell structures onto reduced graphene oxide (rGO) sheets. Carbonization of glucose polymer formed carbon shells existing between the Fe3O4 particles and rGO sheets. The structure of core-shells placed on rGO sheets formed close connections and high structural stability to the Fe3O4@C-rGO (FCG) composite. Reversible specific capacity up to 884 mA h g−1 at 0.2 C with good recyclability was achieved with FCG as an anode material of lithium-ion batteries. These unique three-dimensional structures of core-shells on sheets are beneficial to enhancing lithium-ion battery storage capacity, cycle stability, and rate performances.

Single factor combined with uniform design were used to optimized the extraction process of protein from Momordica charantia residue by salt dissolving method,and the inhibitory activity in vitroon K562 cell proliferation of crude extract was determined by MTT assay.The test results showed that the optimal conditions were as followed:salt concentration of 0.25 mol/L,time 3.59 h,pH=9,ratio of liquid-material 10.36 ∶ 1 (mL/g) and the temperature of 25 ℃,extracting twice.Under this condition,the actual extraction rate was 9.28％.In the range of experimental concentration,the crude protein from Momordica charantia residue had a significant inhibitory effect on proliferation of K562 cells in vitro,and showed dose-effect relationship.

Ruthenium/reduced graphene oxide nanocomposites (Ru/rGO NCs) were synthesized via an electrostatic self-assembly approach. Polyvinylpyrrolidone (PVP) stabilized and positively charged metallic ruthenium nanoclusters about 1.2 nm were synthesized and uniformly loaded onto negatively charged graphene oxide (GO) sheets via strong electrostatic interactions. The as-prepared Ru/rGO NCs exhibited superior performance in catalytic hydrolysis of sodium borohydride (NaBH4) to generate H2. The hydrogen generation rate was up to 14.87 L H2 min−1 gcat −1 at 318 K with relatively low activation energy of 38.12 kJ mol−1. Kinetics study confirmed that the hydrolysis of NaBH4 was first order with respect to concentration of catalysts. Besides, the conversion of NaBH4 remained at 97% and catalytic activity retained more than 70% after 5 reaction cycles at room temperature. These results suggested that the Ru/rGO NCs have a promising prospect in the field of clean energy.

In this work, a Mg-LiFePO4/C composite was synthesized by an aqueous rheological phase assisted method using intermediate FePO4 center dot 2H(2)O, which was prepared from lost cost Fe-3(PO4)(2)center dot 8H(2)O precursor. The oxidation process of Fe-3(PO4)(2)center dot 8H(2)O, rheological phase technology and Mg ion doping improved the purity, elements uniformity, as well as ionic and electronic conductivities of LiFePO4 materials, resulting in the enhanced electrochemical performances of Mg-LiFePO4/C composites. The as-synthesized Mg-LiFePO4/C composite exhibited higher specific capacity and more superior rate capability with a discharge capacity of 153 mAh g(-1) at 0.2 C and 130 mAh g(-1) at 5 C, compared with the undoped LiFePO4/C and the Mg-LiFePO4/C composite synthesized directly using the Fe-3(PO4)(2)center dot 8H(2)O as precursor. This provides an economical and environmentally friendly way for production of LiFePO4 materials as cathode material in lithium ion batteries.

In this work, a Mg-LiFePO4/C composite was synthesized by an aqueous rheological phase assisted method using intermediate FePO4·2H2O, which was prepared from lost cost Fe3(PO4)2·8H2O precursor. The oxidation process of Fe3(PO4)2·8H2O, rheological phase technology and Mg ion doping improved the purity, elements uniformity, as well as ionic and electronic conductivities of LiFePO4 materials, resulting in the enhanced electrochemical performances of Mg-LiFePO4/C composites. The as-synthesized Mg-LiFePO4/C composite exhibited higher specific capacity and more superior rate capability with a discharge capacity of 153 mAh g−1 at 0.2 C and 130 mAh g−1 at 5 C, compared with the undoped LiFePO4/C and the Mg-LiFePO4/C composite synthesized directly using the Fe3(PO4)2·8H2O as precursor. This provides an economical and environmentally friendly way for production of LiFePO4 materials as cathode material in lithium ion batteries.

LiFePO4 composites were synthesized by aqueous ball milling and carbon thermal reduction from FePO4 center dot 2H(2)O through a rheological phase using acetic acid as dispersant. The rheological phase assisted method using acetic acid as dispersant improved the homogeneity of mixing raw materials. Li deficiency and solid-solution Mg dopant in the lattice of LiFePO4 was created through controlled off-stoichiometry Li/Fe ratio. Li deficiency, solid-solution Mg doping and uniform carbon layer decreased electron transfer and Li-ion diffusion resistance. The optimal LiFePO4 composite exhibited a high rate capability with 153 mA.h.g(-1) at 1 C and 111 mA.h.g(-1) at 20 C as well as a stable capacity retention with 99% for 100 cycles at 2 C and 98% for 200 cycles at 5 C. The rheological phase assisted method from FePO4 with acetic acid as dispersant is a promising route for production of high quality LiFePO4 materials at a reasonable cost. (C) 2015 Elsevier Ltd. All rights reserved.

A uniform distribution of doped metal and coated carbon in the as-prepared LiFePO4material is obtained. The LiFePO4delivers a discharge capacity of 166 mA h g−1at 0.1C and presents excellent rate capacity and a high potential plateau at 1C.

综述了磺酰脲类除草剂在土壤中的吸附与解吸、降解、迁移等物理化学行为与土壤pH、有机质含量、黏粒含量等因素的关系,以及除草剂残留对后茬作物的影响.

从应用型本科化学实验教学现状出发,依据培养目标、课程标准、教学内容,对现行教学方法进行了全面改革,构建了"教学理念现代化,教学方式灵活化,学习形式多样化,实验教学生活化,考核方式多元化"的"五化"模式化学实验教学方法,旨在锻炼学生的动手能力,培养学生的创新意识,全面提升学生的科学素养和职业能力.

Calcium zincate microcrystals are successfully prepared with calcium carbonate and zinc oxide as reactants in alkaline solution without protective atmosphere. The structure and composition are analyzed by X-ray powder diffraction (XRD) analysis, thermodiffractometry, scanning electron microscope (SEM), energy dispersive X-ray analysis (EDS), and thermogravimetric analysis (TGA). Electrochemical measurement results prove that the as-synthesized calcium zincate exhibits a good reversibility, a high specific capacity and a good cycling stability. This is a cheap and facile way to synthesize calcium zincate materials which may benefit for mass production of calcium zincate. (C) 2014 The Electrochemical Society. All rights reserved.

采用王水消解,用全谱直读电感耦合等离子体发射光谱法(ICP-AES)同时测定污泥中铅、镉、铬,方法的回收率分别是92%、95%、101%,相对标准偏差分别为0.9359%、1.4061%、0.4524%,符合仪器要求,分析结果与原子吸收法比较,无显著差异。

A new leather fatliquor was studied in this paper.Castor oil and phosphorus pentoxide were used to synthesize the compound.With the optimum condition of castor oil / carbinol(mol∶mol) 1∶2～3,transesterification oil / phosphorus pentoxide(weight∶weight) 100∶15～20,phosphating oil / water(weight∶weight) 100∶6.The physical and chemical properties of the product had been tested in the applied experiments.The results showed that the product,as a new and higy-class leathe fatliquor,has a brilliant prospect.

The development of the dry,wet and electrochemical methods of preparation of potassium ferrate is discussed and its applications of oxidant performance in water treatment and in organic synthesis are reviewed.The prospects of further researches on potassium ferrate are suggested as well.

A supramolecular compand [Cd(C6H4O2N)2(H2O)4 ] was synthesized by the reaction of Cd(NO3) 2·6H2O and isonicotinic.The results of single-crystal X-ray diffraction revealed that it consists of [Cd(C6H4O2N)2(H2O)4 ] units in which the Cd(Ⅱ) ion is located in a slightly distorted octahedral center.Each unit is connedted by the OH...O hydrogen bonds to form a three-dimensional layered structure.