Synthesis of CaCu_3Ti_4O_(12)powders and ceramics by sol-gel method using decanedioic acid and its dielectric properties

The CaCu3Ti4O12 xerogels, powders and ceramics were prepared through the sol-gel method using two kinds of organic acid （decanoic acid and decanedioic acid）. The xerogels, powders and ceramics were characterized by the methods of TG-DTG, FT-IR, XRD, SEM and TEM. The dielectric properties of the ceramics were also measured. The results indicated that the powders calcined at 850 ℃ for 2 h are both nanometer scale particles. After sintering, the ceramics mainly consist of the CaCu3Ti4O12 phase. Compared with the powders prepared using monoacid, the particle size of the powders prepared using diacid obviously increases, and the grain size, the relative density and the whole permittivity of the ceramics increase as well. Specially, the ceramic prepared using decanedioic acid has higher relative density （97.3%）, dielectric constant （316 808） and lower dielectric loss （0.242 5） at 30 ℃ （10 kIaz）

Research on the High-Strength Coating Preparation Methodology based on Acid Catalytic and Sol-Gel Method

In this paper, we conduct research on the high-strength coating preparation methodology based on acid catalytic and Sol-Gel method. This method has been widely used in the preparation of various functional thin film, film and protective film structure, etc. As a result of sol gel process continuously broaden the application field, this method has been more and more get the favor of people. Compared with other traditional preparation methods of inorganic material, sol-gel process has many characteristics. To adjust the solution acidity and add a small amount of acid or alkali can have the effect of＂ catalyst, its reaction process on sol to get and gel structure may also be affected. Our research analyze the topic theoretically and numerically which is meaningful.

Preparation and optical characteristics of ZnO films by chelating sol-gel method

The effect of different annealing temperatures on the structure, morphology,and optical properties of ZnO thin films prepared by the chelating sol-gel method was investigated.Zinc-oxide thin films were coated on quartz glass substrates by dip coating. Zinc nitrate, absoluteethanol, and citric acid were used as precursor, solvent, and chelating agent, respectively. Theresults show that ZnO films derived from zinc-citrate have lower crystallization temperature (below400℃), and that the crystal structure is wurtzite. The films, treated over 500℃, consist ofnano-particles and show to be porous at 600℃. The particle size of the film increases with theincrease of the annealing temperature. The largest particle size is 60 nm at 600℃. The opticaltransmittances related to the annealing temperatures become 90% higher in the visible range. Thefilm shows a starting absorption at 380 nm, and the optical band-gap of the thin film (fired at500℃) is 3.25 eV and close to the intrinsic band-gap of ZnO (3.2 eV).

Improved activity of Ni-Mo/SiO_(2) bimetallic catalyst synthesized via sol-gel method for methylcyclohexane cracking

To improve the cracking behavior of hydrocarbon,Ni-Mo/SiO_(2) bimetallic catalysts were synthesized by different preparation methods(sol-gel,co-impregnation and single-impregnation) and added the additives(citric acid,polyethylene glycol and cetyltrimethylammonium bromide) based on the most suitable method above.The cracking reaction of methylcyclohexane under supercritical conditions was performed as the probe reaction to estimate the catalytic performance,and the properties of Ni-Mo/SiO_(2) catalyst were characterized by N_(2) absorption-desorption,XRD,XPS,H_(2)-TPR,NH_(3)-TPD,in-situ IR of NH_(3) desorption,HRTEM and STEM-mapping so as to study the structure-activity relationship.The catalyst synthesized via sol-gel method showed the best conversion and heat sink,being 81.8% and 3.81 MJ/kg,which was closely related to strong mutual effect between active components and SiO_(2) as well as strong acid sites.Besides,the introduction of additives by sol-gel method has an affirmative influence on properties of Ni-Mo/SiO_(2) catalysts,being that the acidity(more L and B acid sites) was modulated and organic groups interact with metal to suppress the aggregation of metal species(Ni and Mo),thereby enhancing the catalytic activity.At 750℃,the conversion(89.3%) as well as heat sink(3.99 MJ/kg) of MCH cracking obtained an optimum over Ni-Mo/SiO_(2) catalyst with addition of citric acid.

Preparation and electrochemical performance of Li_2Mn_(0.5)Fe_(0.5)SiO_4 cathode material with sol-gel method for lithium ion batteries

Li2Fe0.5Mn0.5SiO4 material was synthesized by a citric acid-assisted sol-gel method. The influence of the stoichiometric ratio value of n(citric acid) to n(Fe2+-Mn2+) on the electrochemical properties of Li2Fe0.5Mn0.5SiO4 was studied. The final sample was identified as Li2Fe0.5Mn0.5SiO4 with a Pmn21 monoclinic structure by X-ray diffraction analysis. The crystal phases components and crystal phase structure of the Li2Fe0.5Mn0.4SiO4 material were improved as the increase of the stoichiometric ratio value of n(citric acid) to n(Fe2+-Mn2+). Field-emission scanning electron microscopy verified that the Li2Fe0.5Mn0.5SiO4 particles are agglomerates of Li2Fe0.5Mn0.5SiO4 primary particles with a geometric mean diameter of 220 nm. The Li2Fe0.5Mn0.5SiO4 sample was used as an electrode material for rechargeable lithium ion batteries, and the electrochemical measurements were carried out at room temperature. The Li2Fe0.5Mn0.5SiO4 electrode delivered a first discharge capacity of 230.1 mAh/g at the current density of 10 mA/g in first cycle and about 162 mAh/g after 20 cycles at the current density of 20 mA/g.

A new solid acid SO_4^(2-)/TiO_2 catalyst modified with tin to synthesize 1,6-hexanediol diacrylate

A new solid acid catalyst,SO4^2-/TiO2 modified with tin,was prepared using a sol-gel method and its physicochemical properties were revealed by nitrogen adsorption-desorption,X-ray powder diffraction,scanning electron microscopy,Fourier transform infrared spectroscopy,infrared spectroscopy of adsorbed pyridine,temperature-programmed desorption of ammonia and thermal gravimetric analysis.The structure,acidity and thermal stability of the SO4^2-/TiO2-SnO2 catalyst were studied.Incorporating tin enlarged the specific surface area and decreased crystallite size of the SO4^2-/TiO2 catalyst.The total acid sites of the modified catalyst increased and Bronsted acid strength remarkably increased with increasing tin content.The decomposition temperature of sulfate radical in the modified catalyst was 100 ℃ greater and its mass loss was more than twice that of the SO4^2-/TiO2 catalyst.The SO4^2-/TiO2-SnO2 catalyst was designed to synthesize 1,6-hexanediol diacrylate by esterification of 1,6-hexanediol with crylic acid.The yield of 1,6-hexanediol diacrylate exceeded 87% under the optimal reaction conditions：crylic acid to 1,6-hexanediol molar ratio = 3.5,catalyst loading = 7%,reaction temperature = 130 ℃ and reaction time = 3 h.The modified catalyst exhibited excellent reusability and after 10 cycles the conversion of 1,6-hexanediol was above 81%.

Sol-Gel Synthesis Using Novel Chelating Agent and Electrochemical Characterization of Binary Doped LiMn2O4 Spinel as Cathode Material for Lithium Rechargeable Batteries

LiMn2O4 and LiCuxCryMn2-x-yO4 (x = 0.50;y = 0.05 - 0.50) powders have been synthesized via sol-gel method for the first time using Myristic acid as chelating agent. The synthesized samples have been taken to physical and electrochemical characterization such as thermo gravimetric analysis (TG/DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and electrochemical characterization viz., electrochemical galvanostatic cycling studies, electrochemical impedance spectroscopy (EIS) and differential capacity curves (dQ/dE). XRD patterns of LiMn2O4 and LiCuxCryMn2-x-yO4 confirm high degree of crystallinity with good phase purity. FESEM image of undoped pristine spinel lucidly depicts cauliflower morphology with good agglomerated particle size of 50 nm while 0.5-Cu doped samples depict the pebbles morphology. TEM images of the spinel LiMn2O4 and LiCu0.5Cr0.05Mn1.45O4 authenticate that all the synthesized particles via sol-gel method are nano-sized (100 nm) with spherical surface and cloudy particles morphology. The LiMn2O4 samples calcined at 850℃ deliver the high discharge capacity of 130 mA·h/g with cathodic efficiency of 88% corresponds to 94% columbic efficiency in the first cycle. Among all four compositions studied, LiCu0.5Cr0.05Mn1.45O4 delivers 124 mA·h/g during the first cycle and shows stable performance with a low capacity fade of 1.1 mA·h/g cycle over the investigated 10 cycles.

丙二酸溶胶-凝胶法合成亚微米级YAG:Ce,Gd黄色荧光粉

以丙二酸为络合剂,通过溶胶-凝胶法合成了亚微米级YAG:Ce,Gd黄色荧光粉。采用TG/DSC、XRD研究干凝胶热分解和YAG晶相形成的过程;通过荧光光谱分析了Gd3+的掺杂对荧光粉的发光强度的影响规律;通过SEM观察粉体的微观形貌。结果表明:经1200℃煅烧3h得到的荧光粉,粉体粒径为0.3～1μm,颗粒规则接近球形;随着Gd3+掺杂量的增加,荧光粉的发射光谱由525nm红移到550nm。

大鼠脑缺血再灌注后诱导型环氧合酶和丙二醛的表达及川芎嗪的干预作用

目的探讨脑缺血再灌注损伤后诱导型环氧合酶(COX-2)和丙二醛(MDA)的表达及其意义,为治疗缺血性脑病提供实验依据。方法以线栓法制作大鼠大脑中动脉阻塞的局灶性脑缺血再灌注模型,采用免疫印迹法和硫代巴比妥酸法以及与神经行为相结合的方法,观测缺血再灌注侧大脑皮质内COX-2和MDA的表达和神经功能的变化,2,3,5-氯化二苯四氮唑(TTC)染色观测脑梗死体积的变化。结果MDA与COX-2的表达呈正相关(r=0.910,P<0.01)。COX-2和MDA在假手术组含量均较低,I2h/R6h两者均有明显升高,并随再灌注时间延长逐渐升高,在I2h/R24h达高峰,I2h/R48h略有下降,但仍维持在较高水平;与I2h/R24h模型组比较,川芎嗪治疗组的脑梗死体积明显减小(P<0.01),MDA含量明显降低(P<0.01)。结论脑缺血再灌注后,COX-2和MDA的表达较正常组明显增多,是导致脑缺血再灌注损伤的因素之一。川芎嗪对大鼠脑缺血再灌注损伤有保护作用。

微波辐射下无溶剂法呋喃丙烯酸的合成

研究了微波辐射下无溶剂法呋喃丙烯酸的合成。以糠醛为反应底物,丙二酸为试剂,吡啶为催化剂,在无溶剂的条件下,考察了糠醛与丙二酸的摩尔比,微波功率,反应时间,催化剂用量,等对反应的影响。经认知实验和正交实验研究得到最佳的反应条件:糠醛:丙二酸:吡啶=1:2.5:3.57,功率180W,反应时间5min.产率达92.8%。结果表明,微波辐射下无溶剂法呋喃丙烯酸的合成,操作简单,反应迅速,产率高,对环境友好,具有一定的应用价值。

基于代谢控制育种技术选育深黄被孢霉γ-亚麻酸高产菌株

为了获得深黄被孢霉合成γ-亚麻酸(GLA)的高产菌株,该研究采用了紫外照射和氮离子注入技术2种诱变方法建立突变体库。根据γ-亚麻酸代谢合成途径中的部分关键因子,设计并建立抗丙二酸和红四氮唑(TTC)筛选模型,旨在提高菌体生物量和不饱和脂肪酸含量。结果显示,采用丙二酸质量浓度为2 g/L的平板可筛选得到高产油脂菌株;在发酵培养的第54小时收集菌体,用0.9%TTC染色4 h,可作为TTC法的最佳染色条件。经过两轮不同方法的诱变筛选后,最终得到了一株具良好遗传稳定性的突变株I-0281,其GLA产量为889.80 mg/L,比原始菌株提高了60.27%。

微波辅助“一锅煮”合成香豆素-3-羧酸类化合物

以取代水杨醛和丙二酸二乙酯为原料,乙醇为溶剂,以吡咯为碱于140℃微波反应20 min,再加入氢氧化钠于120℃微波反应10 min,采用“一锅煮”的方法合成了8个香豆素-3-羧酸类化合物,收率可达84.0%~96.6%。本方法具有反应时间短、产率高、操作简便的优点,为香豆素-3-羧酸类化合物提供了一种高效、便捷的实验室合成方法。

合成长春西汀中间体γ-羟丙基-乙基丙二酸的新方法

2-乙基丙二酸二乙酯和1-溴-3-氯丙烷在氢化钠的作用下,合成中间体γ-氯丙基-乙基丙二酸二乙酯,然后在氢氧化钠的乙醇-水溶剂中水解得到γ-羟丙基-乙基丙二酸。该制备方法原料易得,成本低,完全割除了以往文献报道的高真空减压蒸馏操作,工艺过程更为简单,非常适合工业化生产。总收率80%,产品含量可达98%（HPLC）,其结构经-1H NMR和IR确证。

丙二酸二异丙酯的合成工艺研究

以丙二酸与异丙醇为原料,采用超强固体酸为催化剂合成了丙二酸二异丙酯,收率较高达到95%,后处理简单,提供了一种较优的合成方法。

^(1)H-NMR定量测定黄芪注射液中亲水性成分和疏水性成分

目的建立黄芪注射液中亲水性成分和疏水性成分的^(1)H-NMR定量分析方法。方法以10%氘代水(10%D2O)和氘代甲醇(CD3OD)为氘代溶剂制备黄芪注射液亲水性成分和疏水性成分的^(1)H-NMR样品。使用Bruker Avance Ⅲ 600型核磁共振波谱仪采集^(1)H-NMR图谱,具体实验参数如下:Noesygppr1D脉冲序列;温度为298 K,数据点32 K,采集时间(AQ)为2.980 s,脉冲宽度(SW)为7211.54 Hz,弛豫延迟时间(D1)分别为15.0 s和20.0 s,频率偏移(O1)分别为2816.65 Hz和2930.31 Hz,接收器增益(RG)值为57,扫描次数(NS)32次。结果在^(1)H-NMR图谱中归属出33种成分,分别是异亮氨酸、亮氨酸、缬氨酸、丙氨酸、乳酸、焦谷氨酸、天冬酰胺、γ-氨基丁酸、脯氨酸、甲酸、乙酸、富马酸、苹果酸、琥珀酸、丙二酸、蔗糖、果糖、半乳糖、葡萄糖、胆碱、甜菜碱、葫芦巴碱、尿苷、腺苷、胞苷、鸟苷、腺嘌呤、黄芪皂苷Ⅲ、黄芪甲苷、芒柄花苷、毛蕊异黄酮苷、9,10-二甲氧基紫檀烷-3-O-葡萄糖苷以及异黄烷苷。对其中27种化学成分(异亮氨酸、缬氨酸、丙氨酸、乳酸、焦谷氨酸、天冬酰胺、γ-氨基丁酸、脯氨酸、甲酸、乙酸、富马酸、苹果酸、琥珀酸、丙二酸、蔗糖、果糖、葡萄糖、胆碱、甜菜碱、葫芦巴碱、尿苷、腺苷、鸟苷、腺嘌呤、黄芪皂苷Ⅲ、黄芪甲苷、毛蕊异黄酮苷)进行定量,可定量的成分占注射液固含量90%以上。该方法的精密度、重复性、样品稳定性和耐用性良好,各个成分线性关系良好,r 2大于0.9990,加样回收回收率为98.19%~101.40%。结论建立了一种简单、快速、可靠的^(1)H-NMR定量方法用于测定黄芪注射液中的亲水性成分和疏水性成分,为黄芪注射液的质量评价提供了新的分析手段。

Preparation and Electrochemical Performance of Nano-Co_3O_4 Anode Materials from Spent Li-Ion Batteries for Lithium-Ion Batteries

A hydrometallurgical process for the recovery of cobalt oxalate from spent lithium-ion batteries was used to recycle cobalt compound by using alkali leaching, reductive acid leaching and chemical deposition of cobalt oxalate. The recycled cobalt oxalate was used to synthesize nano-Co3O4 anode material by sol-gel method. The samples were characterized by thermal gravity analysis and differential thermal analysis （TGA/DTA）, X-ray diffraction （XRD）, scanning electron microscopy （SEM） and charge/discharge measurements. The influence of molar ratio of Co2＋ to citric acid and calcination temperature on the structure and electrochemical performance of nano-Co3O4 was evaluated. As the molar ratio of Co2＋ to citric acid is 1：1, the face-centered cubic （fcc） Co3O4 powder shows the discharge capacity of 760.9 mA h g-1, the high coulombic efficiency of 99.7% in the first cycle at the current density of 125 mA g-l, and the excellent cycling performance with the reversible capacity of 442.3 mA h g-1 after 20 cycles at the current density of 250 mA g-1.

丙二酸碘量法与改良五步碘量法测定二氧化氯含量的方法探讨

目的探讨国家标准测定方法在测定二氧化氯含量上遇到的难点和需要改进的建议。方法采用丙二酸碘量法测定样本,测定结果与改良五步碘量法测定的结果进行分析比较。结果改良五步碘量法在测定稳定二氧化氯溶液时,必须按产品说明书先活化样品后测定,测定结果为23 068.6 mg/L;丙二酸碘量法无需活化直接吸取样品测定,测定结果为24 309.0 mg/L。2种方法在测定二氧化氯固体释放剂二氧化氯释放量时,均需按产品说明书先活化样品后测定,均需另取一份样品通入高纯氮赶氯气和二氧化氯测定亚氯酸根含量,操作步骤繁琐。改良五步碘量法测定结果为2 222.0 mg/L,丙二酸碘量法测定结果为1 826.5 mg/L,结果偏低。结论在测定稳定二氧化氯溶液时,丙二酸碘量法无需活化直接吸取样品测定,操作简单,在实际运用时方便准确。在测定二氧化氯固体释放剂二氧化氯释放量时,丙二酸碘量法测定结果偏低,分析实验原理测定结果数据应除以0.8进行修正。

Synthesis and characterization of nano-sized YAG:Ce,Sm spherical phosphors

YAG：Ce,Sm spherical phosphors were synthesized by malic acid sol-gel method. The formation process of crystalline was characterized by X-ray diffraction （XRD） technique. The influence of Sm3＋ doping on the luminescent intensity and the morphology of phosphors were studied by fluorescence spectrum and scanning electron microscopy （SEM） techniques, respectively. The results indicated that the size of spherical powders was about 100 um calcined at 1200 ℃ for 3 h. The emission spectra of phosphors showed gradual red-shift from 525 to 540 um with the increase of doping concentration of Sm3＋ ion. A broadband emission specmtm of Ce3＋ ion appeared at 540 nm, and a series of emission peaks corresponding to the 4Gs/2-＋6Hd transition of Sm3＋ ion also appeared at 617 um with the doping of Sm3＋. The red component of YAG：Ce phosphors increased with the doping of Sm3＋.