共查询到20条相似文献，搜索用时 15 毫秒
1.
以木屑为原料,高温热解制备生物炭。以聚乙烯醇为粘结剂,采用混合法将生物炭与果胶复合,并负载磁性,经烘干定型制备果胶包覆的磁性生物炭材料（果胶@生物炭-Fe3O4）。采用扫描电镜（SEM）、X射线衍射（XRD）及N2吸附-脱附（BET）等方法对果胶@生物炭-Fe3O4进行表征,结合吸附实验分析其对Cu2+的吸附特性。结果表明,当生物炭、果胶、Fe3O4质量比为5：1：1,溶液pH值为6,吸附24 h,果胶@生物炭-Fe3O4对Cu2+吸附效果最好;二级动力学方程能较好地描述果胶@生物炭-Fe3O4对Cu2+的吸附过程,Freundlich模型能较好地拟合其吸附行为;SEM结果显示该材料具有不规则的孔隙结构;XRD分析显示纳米Fe3O4是其主要的晶体结构;BET测得其比表面积为25.654 m2·g-1,平均孔径为20.18 nm。 相似文献
2.
结合电泳法和电沉积法制备了含碳纳米管(CNT)夹层的PbO_2电极(CNT-PbO_2),扫描电子显微镜图像表明,在CNT夹层表面电沉积10minβ-PbO_2活性层可获得β-PbO_2晶粒较多、晶粒尺寸较小、比表面积较大的CNT-PbO_2电极。利用CNT-PbO_2电极电催化氧化降解水中苯胺,研究电流密度、苯胺初始浓度、温度、支持电解质浓度对苯胺降解率的影响。实验结果表明:随着电流密度的增加,苯胺的降解率升高;苯胺初始浓度越高,苯胺的降解率越低;在实验范围内,温度和支持电解质浓度对电催化氧化降解苯胺过程影响较小。 相似文献
3.
利用EF-H_2O_2-FeO_X法深度处理畜牧业养殖废水,结果表明,当pH值为3,电压为24 V,反应时间为45 min,电解质投加量为0.8 g/L,PAM投加量为2.5 mg/L时,对畜牧业养殖废水的深度处理效果最佳,COD的去除率可以达到99.1%。此方法具有成本低、设备简单、效果好等优点,在畜牧业养殖废水的深度处理领域具有广阔的应用前景。 相似文献
4.
5.
文章基于密度泛函理论,研究了本征及Nb,Fe单原子掺杂单层MoSe2的电子结构及光学性质。计算发现,本征单层MoSe2和Nb-MoSe2为直接带隙半导体,Fe-MoSe2为间接带隙结构;Fe-MoSe2较本征单层MoSe2导电性大大提高,实现了由半导体向半金属的过渡。由态密度分析得出了本征及Nb,Fe单原子掺杂单层MoSe2能量状态主要由Mo 4d,Se 4p轨道电子所贡献的结论,并对各原子掺杂体系轨道电子的能量贡献和掺杂类型做了探讨。此外,还详细分析了费米能级附近的自旋态密度、杂质带、磁性之间的联系。光学性质方面,比较了本征单层MoSe2与各掺杂体系的复介电常数和光吸收系数,在红外光区Fe-MoSe2的吸收系数高于本征单层MoSe2。本征单层MoSe2的光吸收系数为9.69×104 cm-1,是区域最大吸收峰。上述研究表明,通过对单层MoSe2的Nb,Fe掺杂可使电子输运特性得到了增强,为高活性自旋电子和光电子器件设计和研究开辟了新的前景。 相似文献
6.
This work investigated the microwave dielectric properties of A-site substitution by rare earth La3+in(Pb0.5Ca0.5)(Fe0.5Ta0.5)O3(PCFT) system.A single perovskite phase was obtained only when the doping content was 2%.Suitable La3+ doping improved microwave dielectric performances.Excessive La3+doping caused the formation of secondary phase,which resulted in the decreasing of permittivity εrand quality factor Qfvalues.Especially,when the doping content is 2%-5%,permittivity εrwas above 75 and Qfvalues were 6... 相似文献
7.
The structural characteristics and optical and electrical properties of molecular-beam-epitaxy (MBE) grown ZnS0.8Se0.2 thin films on indium-tin-oxide(ITO) glas substrates were investigated in this work. TheX-ray diffraction (XRD) results indicated that high quality polycrystalline ZnS0.8Se0.2 thin film grown at the optimized temperature had a prefered orientation along the (111) planes. The transmission electron
microscopy (TEM) cross-sectional micrograph of the sample showed a well defined columnar structure with lateral crystal dimension
in the order of a few hundred angstroms. Ultraviolet (UV) photoresponsivity as high as 0.01 A/W had been demonstrated and
for wavelengths longer than 450 nm, the response was down from the peak response by more than 3 orders of magnitude. The thin
ZnS0.8Se0.2 photosensor layer, with a wide energy gap and anisotropic electrical property, makes a transmission UV liquid crystal light
valve (LCLV) with high resolution feasible.
Project supported by the National Natural Science Foundation of China (No. 59910161981) and RGC grant from the Hong Kong Government
Grant (No. NSFC/HKUST 35), China 相似文献
8.
Chemically processed Nb-doped SrTiO3 films and properties 总被引：1，自引：0，他引：1
Ming-zhi Yin 《浙江大学学报(A卷英文版)》2006,7(8):1436-1439
Homogeneous, crack-free SrNbxTi1−x
O3 thin films on (110) silicon substrates were successfully fabricated by sol-gel processing. The optimum route and conditions
were systematically investigated. Sr(OAc)2 glacial acctic acid solution, after being refluxed and reacted with tartrate, formed Sr(OAc)2(C4H6O6)2; Ti(OBu)4 formed Ti(OAc)4−x
(AcAc)x after having the ligand partially exchanged with AcAc, while Nb(OC2H5)5 formed (OAc)2Nb(AcAc) (C4H6O6) by exchanging of ligand in glacial acetic acid with (CH3CO)2O. All the metal species after undergoing partial hydrolysis and polymerization with hydroxyl or oxygen, formed SrNbxTi1−x
O13 cluster sol. Methyl cellulose (MCL) caused SrNbxTi1−x
O3 sol to have polymeric structure and easily form films. SrNbxTi1−x
O3 films with perovskite were subsequently formed after being annealed at 650∼750 °C for 60 min in 25% N2+75% H2 (volume ratio) atmosphere. Resistivity of the SrNb0.1Ti0.9O3 films at room temperature was 64 μω·cm, a particular T
2 temperature dependence of the resistivity, from 25 K up to room temperature, was observed.
Project (No. 2002CB613305) supported by the National Basic Research Program (973) of China 相似文献
9.
Measurement of the thermal transport properties of dielectric thin films using the micro-Raman method 总被引：1，自引：0，他引：1
The micro-Raman method is a non-contact and non-destructive method for thermal conductivity measurement. To reduce the measurement error induced by the poor fit of the basic equation of the original micro-Raman method, we developed a new basic equation for the heat source ofa Gaussian laser beam. Based on the new basic equation, an analytical heat transfer model has been built to extend the original micro-Raman method to thin films with submicrometer- or nanometer-scale thickness. Experiments were performed to measure the thermal conductivity of dielectric thin films with submicrometer- or nanometer-scale thickness. The thermal resistance of the interface between dielectric thin films and their silicon substrate was also obtained. The obtained thermal conductivity of silicon dioxide film is 1.23 W/（m.K）, and the interface thermal resistance between silicon dioxide film and substrate is 2.35×10^-8 m^2.K/W. The thermal conductivity and interface thermal resistance of silicon nitride film are 1.07 W/（m.K） and 3.69×10^-8 m^2.K/W, respectively. The experimental results are consistent with reported data. 相似文献
10.
Pt/Ti bottom electrodes were fabricated on SiO2/Si substrates by magnetron dual-facing-target sputtering system. Lead zirconate titanate(PZT) thin films were deposited on Pt/Ti/ SiO2/Si substrates by radio frequency (RF) magnetron sputtering system. The thickness of PZT thin films which were deposited for 5 h was about 800 nm. XRD spectra show that PZT thin films deposited in Ar ambience and rapid-thermal-annealed for 20 min at 700 ℃ have good crystallization behavior and perovskite structure. AFM micrographs show that mean diameter of crystallites is 70 nm and surface structures of PZT thin films are uniform and dense. Raw mean, root mean square roughness and mean roughness of PZT thin films are 34.357 nm, 2.479 nm and 1.954 nm respectively. As test frequency is 1 kHz, dielectric constant of PZT thin films is 327.6. Electric hysteresis loop shows that coercive field strength, residual polarization strength and spontaneous polarization strength of PZT thin films are 50 kV/cm, 10 μC/cm2 and 13 μC/cm2 respectively. 相似文献
11.
MBE growth of ZnSxSe1−x thin films on ITO coated glass substrates were carried out using ZnS and Se sources with the substrate temperature ranging
from 270°C to 330°C. The XRD σ/2σ spectra resulted from these films indicated that the as-grown polycrystalline ZnSxSe1−x thin films had a preferred orientation along the (111) planes. The evaluated crystal sizes as deduced from the FWHM of the
XRD layer peaks showed strong growth temperature dependence, with the optimized temperature being about 290 °C. Both AFM and
TEM measurements of these thin films also indicated a similar growth temperature dependence. High quality ZnSxSe1−x thin film grown at the optimized temperature had the smoothest surface with lowest RMS value of 1.2 nm and TEM cross-sectional
micrograph showing a well defined columnar structure.
Project supported by the National Science Council of PRC (No. 59910161981) and RGC grant from the Hong Kong Government under
Grant (No. NS-FC/HKUST 35) 相似文献
12.
采用溶胶凝胶的化学溶液沉积法在Pt/Ti/SiO2/Si衬底上制备了不同浓度(0,0.05,0.1 at.%)的Mn掺杂铁酸铋薄膜.薄膜晶体结构的X射线衍射结果显示不同浓度掺杂的薄膜平均晶粒尺寸相差并不大,而薄膜的漏电流分析则表明5%Mn掺杂的铁酸铋薄膜比未掺杂和10%Mn掺杂的薄膜漏电流要小.此外,通过薄膜的铁电性能测试发现5%Mn掺杂的铁酸铋薄膜比未掺杂和10%Mn掺杂的薄膜的铁电性能也要好.根据缺陷化学理论,由氧空位的电荷补偿引起的Fe离子和Mn离子价态变化是产生这一结果的主要原因. 相似文献
13.
Xu Li-heng Chen Zhi-chun Li Yang-mei Lu De-shui Lin Xian-fu Yuan Jun 《浙江大学学报(A卷英文版)》2002,3(5):567-569
Pepsin was assembled on the surface of prepared poly (ethylene terephthalate) (PET-NH3
+) substrates. The composition and structure of the pepsin/PET-NH3
+ assembling films in different condition were characterized by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy
(AFM). 相似文献
14.
(K0.47Na0.47Li0.06)NbO3 (KNLN) lead-free ceramics were prepared by molten salt synthesis (MSS) method using k2CO3-Na2CO3 eutectic mixtures as the flux. The microstructure and piezoelectric properties when sintered at 980-1 030 ℃ were investigated. The calcined powders were examined by X-ray diffraction. The microstructure of the calcined powders and sintered bodies was observed using a scanning electron microscope (SEM).The piezoelectric constant d33 was measured using a quasi-static piezoelectric d33 meter. The planar coupling coefficient Kp was calculated by resonance-antiresonance method. The experimental data for each sample's performance indicators were the average values of 8 specimens. The relative densities of sintered specimens are above 97%, and the dielectric loss is below 0.03. It was found that (K0.47Na0.47Li0.06)NbO3 prepared by MSS is compact and lead-free. The piezoelectric constant d33 is 216 pC·N-1 and the planar electromechanical coupling factor Kp is 0.352. 相似文献
15.
A series of polysulfonamide （PSA）/TiO 2 modifier nano-composite films were successfully prepared by in-situ polymerization at a low temperature based on 4, 4-diaminodiphenylsulfone and terephthaloyl chloride in the common solvent N, N-dimethylacetamide （DMAc）. It was shown that the nano particles were well dispersed in the polymer substrate. Mean-while, PSA/TiO 2 /modifier composites exhibited good UV-resistant properties and mechanical properties. In addition, the composites’ heat stability improved. These prepared composites are promising in preparing spinning solution and might have potential application in heat-resistant fiber. 相似文献
16.
基于相变的热力学理论,数值模拟了单畴BST薄膜在四方结构衬底上的相图,并讨论了其介电特性．研究表明,与立方衬底上的相图相比较,该种情况下的BST相图较为复杂,并有新的铁电相出现．另外,其介电特性的分析表明在相界点部分极化强度分量是不连续的． 相似文献
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18.
Dong-dong Cao Jin Hu Xin-xian Huang Xian-ju Wang Ya-jing Guan Zhou-fei Wang 《Journal of Zhejiang University. Science. B》2008,9(12):964-968
The changes of kernel nutritive components and seed vigor in F1 seeds of sh
2 sweet corn during seed development stage were investigated and the relationships between them were analyzed by time series
regression (TSR) analysis. The results show that total soluble sugar and reducing sugar contents gradually declined, while
starch and soluble protein contents increased throughout the seed development stages. Germination percentage, energy of germination,
germination index and vigor index gradually increased along with seed development and reached the highest levels at 38 d after
pollination (DAP). The TSR showed that, during 14 to 42 DAP, total soluble sugar content was independent of the vigor parameters
determined in present experiment, while the reducing sugar content had a significant effect on seed vigor. TSR equations between
seed reducing sugar and seed vigor were also developed. There were negative correlations between the seed reducing sugar content
and the germination percentage, energy of germination, germination index and vigor index, respectively. It is suggested that
the seed germination, energy of germination, germination index and vigor index could be predicted by the content of reducing
sugar in sweet corn seeds during seed development stages.
Project supported by the National Natural Science Foundation of China (No. 30370911) and Education Department of Zhejiang
Province, China (No. 20070147) 相似文献
19.
通过在底栅顶接触的喷墨打印有机薄膜晶体管的SiO2表面采用原子层沉积方式制备薄层的Al2O3修饰层,并与未修饰前进行比较,发现有源层在ALD-Al2O3修饰后的SiO2表面接触角大大变小,且喷墨打印的有源层线条变粗。而随着ALD-Al2O3修饰层厚度的增加,SiO2表面粗糙度变大。通过测试其电学性能,发现ALD- Al2O3修饰层厚度为1 nm时,OTFT的性能最好,与未修饰前相比,其迁移率提高了近8倍,而开关比提高约4个数量级。 相似文献
20.
INTRODUCTION Monocrystalline SBN (Strontium barium nio-bium, SrxBa1?xNb2O6, denoted SBNx?100, where 0.25≤x≤0.75) solid solution, is currently being inves-tigated as potential material for many micro-device applications, such as piezoelectric infrared detectors, piezoelectric, electro-optic modulators, and holo-graphic storage (Koch et al., 1998), because SBN has one of the largest known linear electro-optic coeffi-cients (r33=1300 pm/V for SBN75), two orders of magnitude larger th… 相似文献