Microstructure and temperature dependence of magnetic properties of CuO-added MnZn ferrites

MnZn ferrites with the chemical formula Mn0.68Zn0.25Fe2.07O4 have been prepared by a conventional ceramic technique. Then, the effects of CuO addition on the microstructure and temperature dependence of magnetic properties of MnZn ferrites were investigated by characterizing the fracture surface micrograph and measuring the magnetic properties over a temperature ranging from 25 to 120 C. The results show that the lattice constant and average grain size increase with the increase of CuO concentration. When the CuO concentration is below 0.07 wt.%, the initial permeability and saturation magnetic flux density increase monotonously, and the temperature of the secondary maximum peak in the curve of initial permeability versus temperature and the lowest power loss shift to a lower temperature with the increase of CuO concentra-tion. However, excessive CuO concentration （0.07 wt.%） results in abnormal grain growth and porosity increase, which causes the initial permeability and saturation magnetic flux density decrease and the power loss increase at room temperature. Furthermore, the temperature of the secondary maximum peak in the curve of initial permeability versus temperature and the lowest power loss shift to a higher temperature.

Fabrication and magnetic properties of NiFe_2O_4 nanorods

NiFe2O4 nanorods have been successfully synthesized via thermal treatment of the rod-like precursor fabricated by Ni-doped （x-FeOOH, which was enwrapped by the complex of citric acid and Niz~. The morphology evolution during the calcination of the precursor nanorods was investigated with transmission electron microscopy （TEM）, and the phase and the magnetic properties of samples were analyzed through X-ray diffraction （XRD） and vibrating sample magnetometer （VSM）. The results indicated that the diameter of the NiFe204 nanorods obtained ranged between 30 and 50 nm, and the length ranged between 2 and 3 um. As the calcination temperature was up to 600℃, the coercivity, saturation magnetization, and remanent magnetization of the samples were 36.1 kA.m^-1, 27.2 A.m2.kg^-1, and 5.3 A.m2.kg^-1, respectively. The NiFe2O4 nanorods prepared have higher shape anisotropy and superior magnetic properties than those with irregular shapes.

Preparation and magnetic properties of Fe_2O_3 microtubules prepared by sol-gel template method

Fe（OH）3 precursor sol was prepared by a sol-gel method. The precursor sol was dipped onto the absorbent cotton, and gel was formed on the absorbent cotton template after the volatilization of moisture. Fe2O3 microtubules were synthesized after the process of self-propagation or calcination. The phase, morphology, and particle diameter of the samples were examined by X-ray diffraction （XRD） and scanning electron microscopy （SEM）, and the magnetic properties of the samples were measured using a vibrating sample magnetometer （VSM）. The external diameters of Fe2O3 microtubules ranged between 8 and 13 μm, and the wall thicknesses ranged between 0.5 and 2 μm. The type of the calcination method plays a significant role in developing the Fe2O3 phase and the variation in the magnetic properties in the sol-gel template complexing method. γ-Fe2O3 was synthesized by a self-propagation method. However, α-Fe203 was synthesized after calcination at 400℃ for 2 h. The coercivity of the samples synthesized by calcination at 400℃ for 2 h after self-propagation was found to increase significantly, thereby presenting hard magnetic properties.

Synthesis and Pigmental Properties of Nickel Phosphates by the Substitution with Tetravalent Cerium Cation

In this paper, we report the preparation of nickel phosphate in aqueous solution and its use as inorganic pigment. Because cerium phosphate is insoluble in acidic and basic solution, the addition of cerium was tried to improve the acid and base resistance of nickel phosphate pigment. The cerium substituted nickel phosphates were prepared from phosphoric acid, nickel nitrate, and ammonium cerium nitrate solution. The additional effects of tetravalent cerium cation were studied on the chemical composition, particle shape and size distribution, specific surface area, color, acid and base resistance of the precipitates and their thermal products.

Synthesis and Thermoelectric Properties of Ca_(2.6)Nd_ ( 0.4)Co_4O_9 Compound

The layered cobaltite Ca 2.6Nd 0.4Co 4O 9 was synthesized by the solid-state reaction. Their crystal structure was determined by the X-ray powder diffraction and CELL program. The prepared Ca 2.6Nd 0.4Co 4O 9 compound has the monoclinic symmetry. The electrical conductivity and Seebeck coefficient were measured from room temperature to 700 ℃ in air. Both the properties increase while rising temperature. The thermoelectric power of Ca 2.6Nd 0.4Co 4O 9 is about 242 4 μV·K -1. The results imply a promising way to enhance the thermoelectric properties of the layered cobaltite oxides by optimizing their composition and microstructure.

Synthesis and Characterization of Layered Co_2(OH)_3(CH_3COO)·H_2O

Layered hydroxide metal acetate Co2（OH）3（CH3COO）·H2O with an interlayer spacing of 1.282 nm has been synthesized by a novel method which is employed in ethanol-aqueous mixed solvents media. Experiment results show that the purity of the product by the modified method is higher compared with that by the previous methods. A complete characterization of the as-prepared samples was performed by means of X-ray powder diffraction, IR spectroscopy, scanning electron microscope, as well as magnetic measurement. The facile and effective approach for the preparation of this compound in this study is very interesting and important because it has wide application in the field of anionic exchange reaction for the synthesis of hybrid organic-inorganic compounds.

Photocatalytic Degradation of 4-chlorophenol by CuMoO₄-doped TiO₂Nanoparticles Synthesized by Chemical Route

The photocatalytic degradation of 4-chlorophenol (4-CP) in aqueous solution was studied using Cu-MoO4- doped TiO2 nanoparticles under Visible light radiation. The photocatalysts were synthesized by chemical route from TiO2 with different concentration of CuMoO4 (CuxMoxTi1-xO6;where, x values ranged from 0.05 to 0.5). The prepared nanoparticles are characterized by XRD, BET surface area, TEM, UV-vis diffuse reflectance spectra, Raman spectroscopy, XPS and EDAX spectroscopy were used to investigate the nanoparticles structure, size distribution, and qualitative elemental analysis of the composition. The CuxMoxTi1-xO6 (x = 0.05) showed high activity for degradation of 4-CP under visible light. The surface area of the catalyst was found to be 101 m2/g. The photodegradation process was optimized by using CuxMoxTi1-xO6 (x = 0.05) catalyst at a concentration level of 1 g/l. A maximum photocatalytic efficiency of 96.9% was reached at pH = 9 after irradiation for 3 hours. Parameters affecting the photocatalytic process such as catalyst loading, concentration of the catalyst and the dopant concentration, solution pH, and concentration of 4-CP have been investigated.

Preparation of titanium dioxide photocatalytic hollow spheres

With coaxial nozzle system, TiO2 hollow spheres were prepared and the optimum parameters of forming TiO2 hollow spheres were fix on as follows: acrylamide (AM) was used as monomer up to 30.3%, acetone was used as vesicant, the mass fraction of initiator was 0.4%, the forming temperature was in the range from 90 ℃ to 95 ℃. The photocatalistic performance of TiO2 hollow spheres was characterized by degradation of methyl orange. Compared with nano-TiO2 powders, hollow spheres can be recycled after cleanout and drying, taking on similar efficiency of photocatalistic.

Controlled synthesis and luminance properties of lanthanide-doped β-NaYF_4 microcrystals

Hexagonal yb3＋,Er3＋-doped NaYF4 crystals with different morphologies were synthesized by a facile hydrothermal method at 140-200 ℃. Their shape and size could be controlled by varying hydrothermal temperature, time and doping effect of Ce3＋ ions. Interestingly, the products displayed hexagonal sheet, plate, crown-like prism to tube changes in the temperature range from 140 to 200 ℃. A combination of ＂diffusion-controlled growth＂ and ＂selective adsorption＂ was proposed to understand the formation of the NaYF4 crystals with well-defined shapes. NaYF4：yb3＋/Er3＋ crystals exhibited shape-dependent up-conversion （UC） luminescence under excitation of 980 nm, and their luminescence property could be tuned by doping Ce3＋ ions.

一次性减氮施有机无机复混肥对夏玉米产量、氮利用、土壤养分的影响

为鲁西北潮土区玉米增产增收和轻简化栽培技术提供理论依据,采用一次性减氮施有机无机复混肥技术,对玉米籽粒产量、可持续性指数、氮效率、土壤养分含量的变化进行研究。试验设置不施肥对照(CK)、常规氮磷钾肥(NPK)、猪粪有机无机复混肥1800 kg·hm^(-2)(OF)3个处理。结果表明:与NPK处理相比,OF处理的氮肥用量减少88 kg·hm^(-2)(35.2%),2017—2022连续6年的玉米平均产量为10549.56 kg·hm^(-2),增产3.94%,籽粒蛋白质产量提高8.22%,可持续性指数最高(0.74),氮素吸收率、氮素利用率、氮肥偏生产力、氮肥农学效率与肥料利用率分别提高0.21%、67.63%、62.86%、71.85%、5.52%;OF处理相较NPK处理可有效降低土壤pH值,0~100 cm土层有机质(SOM)、全氮(TN)、有效磷(AP)和速效钾(AK)含量显著提高6.58%~64.82%、7.22%~8.63%、24.66%~329.26%、14.81%~76.06%;OF处理的0~20 cm土层硝态氮含量比CK、NPK处理提高44.51%和3.68%,NPK处理的20~100 cm土层硝态氮比CK、OF处理提高78.66%~149.05%、23.57%~149.61%,增大了硝酸盐淋溶风险。综上,一次性减氮施有机无机复混肥通过提高土壤养分含量,促进玉米的养分吸收利用,实现夏玉米产量增产3.94%,提高可持续产量指数,是适宜鲁西北潮土区高产农田玉米轻简化生产的有效施肥措施。

Elastic Properties and Stacking Fault Energies of Borides, Carbides and Nitrides from First-Principles Calculations

Owing to the excellent elastic properties and chemical stability,binary metal or light element borides,carbides and nitrides have been extensively applied as hard and low-compressible materials.Researchers are searching for harder materials all the time.Recently,the successful fabrication of nano-twinned cubic BN(Tian et al.Nature 493:385–388,2013)and diamond(Huang et al.Nature 510:250–253,2014)exhibiting superior properties than their twin-free counterparts allows an efficient way to be harder.From this point of view,the borides,carbides and nitrides may be stronger by introducing twins,whose formation tendency can be measured using stacking fault energies(SFEs).The lower the SFEs,the easier the formation of twins.In the present study,by means of first-principles calculations,we first calculated the fundamental elastic constants of forty-two borides,seventeen carbides and thirty-one nitrides,and their moduli,elastic anisotropy factors and bonding characters were accordingly derived.Then,the SFEs of the{111}<112>glide system of twenty-seven compounds with the space group F43 m or Fm3m were calculated.Based on the obtained elastic properties and SFEs,we find that(1)light element compounds usually exhibit superior elastic properties over the metal borides,carbides or nitrides;(2)the 5 d transitionmetal compounds(ReB2,WB,OsC,RuC,WC,OsN2,TaN and WN)possess comparable bulk modulus(B)with that of cBN(B=363 GPa);(3)twins may form in ZrB,HfN,PtN,VN and ZrN,since their SFEs are lower or slightly higher than that of diamond(SFE=277 mJ/m^2).Our work can be used as a valuable database to compare these compounds.

Effect of neodymium doping on structural,microscopic and electrical properties of barium phosphate system

Neodymium-doped barium phosphate(NdBP)was prepared as single crystal by room temperature solution technique known as gel encapsulation technique.Single crystal X-ray diffraction shows that the crystal belongs to orthorthombic system.The flower type morphology was observed by scanning electron microscope(SEM)and the stoichiometric composition of the prepared crystal was observed by energy dispersive X-ray analysis(EDAX).The presence of functional group and other groups was studied by Fourier transform infrared spectroscopy(FTIR).The electrical properties of these materials like dielectric constant(ε′),dieletric loss(tan σ)and ac conductivity[ln(σac)]was studied at different temperatures ranging from 40℃ to 420℃ in the frequency range of 5 kHz to 1 MHz.The activation energy values decreases with increase in frequency suggesting that the conduction mechanism is because of hopping of charge carriers.

Hydrothermal synthesis and optical properties of Zn_(1-x)Mn_xS nanorods

Zn1-xMnxS （x = 0-0.05） nanorods were successfully synthesized through a hydrothermal route. The morphology, composition and microstructure of Zn1-xMnxS nanorods were characterized respectively by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and Raman spectrometer. The optical properties of Zn1-xMnxS nanorods were determineded by UV-Vis absorption spectroscopy and photo- luminescence （PL） emission spectroscopy. The results show that the introduction of Mn^2＋ on interstitial sites in ZnS lattice has significant influence on the Raman spectra, UV-Vis absorption spectra and PL emis- sion spectra. With the increase of Mn^2＋, the lengths of the sampled nanorods become shorter and the morphologies of the products show disorder accompanied by some nanoparticles. The absorption band edge shifts to longer wavelength. The intensity of the ZnS-related emission gradually becomes weaker, whereas, the Mn^2＋-related broad emission spectra located at 580 nm gradually red-shifts and increases. Occupation of Zn^2＋ sites in the lattice by Mn^2＋ ions results in lattice distortion and influences the energy level structure of ZnS. The Mn doping is found responsible for the changes in the defect-related emission of the ZnS nanorods.

一个新的分子拓扑指数

通过将键参数和量子数引入原子点价,重新定义原子点价δYi,认为分子中某一原子的δYi与该原子的杨氏电负性力标、价电子数、成键电子数及最外层主量子数有关.由此提出新的分子拓扑指数mXY.并用一级指数1XY与饱和烷烃的沸点、液体热容、气体热容、蒸发热、临界温度、临界压力,卤代苯的辛醇/水分配系数,烷氧氯硅烷的气相色谱保留指数、含氮杂环化合物的毒性,碱金属卤化物的晶格焓与F心能带,卤化锡的119SnMossbauer等性质/活性进行相关关系的研究.结果表明,1XY与有机物和无机物的性质/活性间具有广泛良好的相关性.

无机层状纳米材料与聚苯胺的复合研究

聚苯胺被认为是最有希望在实际中得到广泛应用的导电聚合物,通过与无机层状纳米材料的复合改性,其复合物在二次电池电解质、光电转换、热电、磁电、电致流变等新材料领域显示出诱人前景。本文对无机层状材料与聚苯胺的复合方法、复合物性质及其应用前景进行了评述。

生物有机无机复合肥效应的初步研究

进行了化肥、有机肥、生物堆肥、有机无机复合肥和生物有机无机复合肥的田间比较试验。初步试验结果表明,施用生物有机无机复合肥可以改善土壤结构,增进土壤肥力,提高土壤供肥能力,提高土壤生物活性。表现为与试前土壤比较,土壤容重下降0.17,总孔隙度提高1.45%,有机质增加0.1%,全量养分和速效养分都有不同程度的提高,三大类微生物总量增加1.64倍,蔗糖酶、脲酶和磷酸酶活性也有不同程度的提高。同时施用生物有机无机复合肥还可以促进植株生长发育,提高产量,改善作物品质。与不施肥处理相比较,增产83.54%,达极显著水平;硝酸盐下降113.0247mg·kg-1;维生素C提高0.2880mg·g-1。结果表明,生物有机无机复合肥综合效果优于其它肥料,具有明显的经济效益和生态效益。

沼肥与生物有机无机复合肥在保护地蔬菜上应用效果研究

试验研究了化肥、生物有机无机复合肥、生物有机肥、沼肥对日光温室秋冬茬黄瓜及对土壤理化性质的影响。试验结果表明,施用沼肥、生物有机肥、生物有机无机复合肥有改善土壤理化性状、增强土壤保水保肥能力的作用。表现为与试前土壤相比较,土壤容重下降,土壤总孔隙度和土壤含水量增加,其中施用沼肥的处理影响最大,土壤容重降低了4.26%,土壤总孔隙度和土壤含水量分别提高了4.68%,10.7%;施用沼肥,耕层土壤有机质、全氮、速效钾含量增加最高,而完全施用生物有机无机复合肥的处理全磷、速效磷、碱解氮增幅最大。施用沼肥和生物有机无机复合肥可以促进黄瓜的生长和提高产量,产量比对照(不施肥处理)分别增加了102.8%,123.1%。各处理除沼肥和生物有机肥两处理间产量差异不显著外,其他处理间差异均达极显著水平。另外,施用沼肥、生物有机肥、生物有机无机复合肥可以提高果实中Vc、还原糖含量,并降低硝酸盐含量,提高了果实品质。

基于线上线下结合的无机定性分析实验教学

针对在实验室开设定性分析实验受到的制约,设计并开设了"无机化合物的性质与鉴定"虚拟实验,以作为常规无机定性分析实验的重要补充和扩展。虚拟实验和传统实验一并开设,构成线上线下结合的教学模式,完善知识体系,全面培养学生的无机定性分析能力。

有机无机复混肥对旱藕生长发育及土壤理化性状的影响

为探讨有机无机复混肥对旱藕生长发育及土壤理化性状的影响,本研究设置有机无机复混肥0、750、1500、2250、3000 kg/hm25个施肥量,进行不同施肥量对土壤理化性状、旱藕农艺性状、产量及品质的影响研究。结果表明:随着有机无机复混肥施用量的增加,土壤孔隙度先增加后减少,土壤碱解氮、速效磷、速效钾及有机质含量逐渐增加;旱藕株高、茎径及分蘖数逐渐增加,但旱藕倒伏率也随之增加;旱藕成熟块茎可溶性糖、还原糖、可溶性蛋白质及淀粉含量逐渐增加;旱藕块茎产量先增加后减少,其中施肥量为2250 kg/hm2的产量最高,比不施肥增产66.01%。综上表明,有机无机复混肥能有效改善土壤理化性状,提高旱藕块茎产量及品质,但施肥量过多会导致土壤板结及旱藕倒伏,块茎产量减少。本研究条件下,有机无机复混肥施肥量为2250 kg/hm2的效果最好。

复配改性黏土/丁腈橡胶纳米复合材料的结构及性能

用不同阴离子表面活性剂十二烷基磺酸钠(SDS)和十二烷基苯磺酸钠(SDBS)与阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)复配改性无机黏土,制备了有机改性黏土/丁腈橡胶(NBR)纳米复合材料,并表征了有机黏土与纳米复合材料,考察了不同表面活性剂及配比对纳米复合材料物理机械性能的影响。结果表明,CTAB/SDS复配改性黏土/NBR纳米复合材料的层间距比CTAB改性黏土/NBR纳米复合材料增加了1.15 nm,具有更多的插层结构,橡胶基体中黏土颗粒分布细致、均匀,且黏土片层间无聚集体存在;CTAB/SDS复配改性黏土/NBR纳米复合材料的物理机械性能优于CTAB/SDBS复配改性黏土/NBR纳米复合材料及CTAB改性黏土/NBR纳米复合材料,且当CTAB/SDS(质量比)为4∶2时,纳米复合材料的拉伸强度、撕裂强度及扯断伸长率出现最大值,其中,拉伸强度和撕裂强度较CTAB改性黏土/NBR纳米复合材料分别提高了62.7%和12.3%。