SrMoO_4：0.05Eu~（3＋）,0.05Gd~（3＋）的制备及发光性能研究

分别采用化学沉淀法、微波法、水热法制备了SrMoO4：0.05Eu3＋,0.05Gd3＋荧光粉,并通过X-射线粉末衍射（XRD）、荧光光谱和扫描电子显微镜（SEM）对其晶体结构、荧光光谱和形貌进行了表征。结果表明：SrMoO4：0.05Eu3＋,0.05Gd3＋的结构属体心四方晶系;其宽激发带由Eu3＋-O2-、Gd3＋-O2-电荷迁移带和Mo6＋-O2-基质吸收峰组成,荧光发光以在616nm处Eu3＋的5 D0→7 F2跃迁引起的红光发光最强;254nm紫外光激发时,化学沉淀法制备SrMoO4：0.05Eu3＋,0.05Gd3＋的发光峰比SrMoO4：0.05Eu3＋的相应发光峰强度增大,这是由于Gd3＋向Eu3＋的能量传递敏化增强了Eu3＋的发光。     

锂离子电池高镍三元正极材料LiNi0.9Co0.05Mn0.05O2的制备与改性

采用La掺杂和固态电解质Li_1.3Al_0.3Ti_1.7(PO4)₃包覆对LiNi_0.9Co_0.05Mn_0.05O₂进行改性，研究掺杂和包覆对LiNi_0.9Co_0.05Mn_0.05O₂结构与性能的影响。结果表明：适量的La掺杂可以降低LiNi_0.9Co_0.05Mn_0.05O₂材料的离子迁移阻抗，提高Li⁺扩散系数，稳定材料的结构，从而提高材料的放电比容量及循环性能，当La掺杂量为0.1 wt%时，首次放电比容量为180.1 mAh·g^-1，经过100次循环后的容量保持率高达93.34%，远高于未掺杂样品的86.20%。Li_1.3Al_0.3Ti_1....     

Zn0.95Fe0.05O稀磁半导体粉体的制备与表征

采用水热法合成Zn_(0.95)Fe_(0.05)O稀磁半导体,通过试验及XRD、FE-SEM对合成的粉体进行分析,在水热合成法合成条件200℃保温24 h、矿化剂NaOH浓度3 mol/l、填充度为60%下,制备出的Zn_(0.95)Fe_(0.05)O纳米晶体发育完全,粒度分布均匀。是合成Zn_(0.95)Fe_(0.05)O纳米晶体的理想方法之一。     

Mg2+和F-共掺杂提高LiNi0.8Co0.15Al0.05O2电化学性能

采用传统固相法对锂离子电池富镍系LiNi0.8Co0.15Al0.05O2正极材料进行了Mg2+和F-共掺杂改性研究,借助X射线衍射(XRD)、XRD数据精修、扫描电子显微镜(SEM)、恒电流充放电测试、循环伏安曲线(CV)和电化学阻抗谱(EIS)等手段探究Mg2+和F-共掺杂对材料晶体结构、表面形貌和电化学性能的影响.物理测试表明,Mg2+和F-共掺杂后正极材料仍保持α-NaFeO2结构,无杂质生成,且共掺杂后正极材料晶胞参数增大,离子混排程度降低,这有利于Li+在晶格中的脱嵌迁移.此外,共掺杂后正极材料的微观形貌未发生明显变化.电化学性能表明,Mg2+和F-共掺杂样品表现出优异的电化学性能,1C倍率下循环200圈后,放电比容量仍保持有144.1mAh·g-1,容量保持率高达83.1％.优异的电化学性能归因于Mg2+和F-稳定了材料的晶体结构,减少了材料极化,抑制了电池电荷转移阻抗的增加.本工作的开展为其他锂离子电池正极材料性能提升提供了思路.     

Mg_2Ni_(0.95)Sn_(0.05)-C_6H_6浆液体系储氢性能

研究了Mg_2Ni_(0.95)Sn_(0.05)和苯以及Mg_2Ni_(0.95)Sn_(0.05)氢化物与苯分别组成的浆液的储氢性能,通过研究不同温度下合金和氢化物对浆液吸氢速率的影响,发现氢化物比合金对浆液的反应速率的影响更为显著。温度对反应的影响特别明显,在反应釜中氢气压力为7 MPa,反应釜桨搅拌速度为500r·min~(-1),温度为513K时合金和氢化物分别和苯组成的浆液表现出最佳的吸氢性能,其最大吸氢量分别达到了5.87％(mass)和6.02％(mass)。添加Sn后的合金Mg_2Ni_(0.95)Sn_(0.05)对苯加氢到环己烷的转化有很好的选择性。     

用于甲烷偶联的SrCe0.95Yb0.05O3-α中空纤维膜反应器建模

Proton-hole mixed conductor, SrCe0.95Yb0.05O3-α(SCYb), has the potential to be used as a membrane for dehydrogenation reactions such as methane coupling due to its high C2-selectivity and its simplicity for fabricating reactor systems. In addition, the mixed conducting membrane in the hollow fibre geometry is capable of providing high surface area per unit volume. In this study, mechanism of methane coupling reaction on the SCYb membrane was proposed and the kinetic parameters were obtained by regression of experimental data. A mathematical model describing the methane coupling in the SCYb hollow fibre membrane reactor was also developed.With this mathematical model, various operating conditions such as the operation mode, operation pressure and feed concentrations affecting performance of the reactor were investigated. The simulation results show that the cocurrent flow in the reactor exhibits higher conversion of methane and higher yield of ethylene compared to the countercurrent flow. In order to achieve the highest C2 yield, especially of ethylene, pure methane should be used as feed and the operating pressure be 300 kPa. Air can be used as the source of oxygen for the reaction and it soptimum feed velocity is twice of the methane feed velocity. The air pressure in the lumen side should be kept the same as or slightly lower than the vressure of shell side.     

Li_4Ti_(4.95)Nb_(0.05)O_(12)负极材料的制备及其电化学性能研究

采用二步固相法制备了Li_4Ti_(4.95)Nb_(0.05)O_(12)负极材料,扫描电镜、激光粒度分布仪、充放电测试和循环伏安等测试结果表明:合成的样品粒径分布均匀,Nb掺杂改性的Li_4Ti_5O_(12)具有优良的电化学性能,0.1 C、0.5 C、1 C和10 C首次放电比容量分别为174.1 m Ah/g、159.7 m Ah/g、147 m Ah/g和123.3 m Ah/g。10 C下,循环20次后容量保持为118.1 m Ah/g。     

电解质Ce0.95Fe0.05O2-δ超细粉体的制备与表征

以硝酸铈与硝酸铁为原料,采用溶胶凝胶法制得电解质材料Ce0.95Fe0.05O2-δ,对其粉末进行了压片、煅烧。采用IR、XRD、SEM、TG等手段对其性能与结构进行了测试和分析。     

细化颗粒固相法合成锂离子电池正极材料LiNi_(0.80)Co_(0.15)Al_(0.05)O_2及其结构和电化学性能研究

利用超细旋转盘式砂磨机细化颗粒固相烧结法,合成锂离子电池正极材料Li Ni0.80Co0.15Al0.05O2。原料经过砂磨后,混合均匀,粒径达到纳米级。根据塔曼定理,混合均匀的微小粒径可以在相同的烧结温度下,提高烧结的强度。SEM、XRD分别表征NCA材料的颗粒形貌和晶形结构。结果显示,通过细化颗粒烧结后的样品具有良好的形貌和层状结构。CV法测试样品的氧化还原性能,电池测试系统测试样品的电化学性能。测试结果显示,经过细化颗粒,在720℃合成的NCA材料具有良好的层状结构,018/110峰分裂明显。样品的电化学性能优良,0.2C下,首次放电容量达到182 m Ah?g?1,30次循环后容量保持率99.9%。1C下,首次放电容量153 m Ah?g?1,100次循环后容量保持率92.6%。     

纳米磁性Ag2S/CoFe1.95Y0.05O4的制备及其光催化性能研究

采用水热合成法制备了纳米CoFe_1.95Y_0.05O₄尖晶石催化剂,在制备Ag₂S的过程中采用简单的化学方法制备了异质结Ag₂S/CoFe_1.95Y_0.05O₄复合光催化剂。利用X射线衍射仪(XRD)、紫外-可见漫反射光谱仪(UV-Vis DRS)、扫描电子显微镜(SEM)、振动样品磁强计(VSM)、高分辨率透射电镜(HRTEM)对所制备Ag₂S/CoFe_1.95Y_0.05O₄进行结构和形态的表征。在可见光照射下降解甲基橙(MO)水溶液,考察制备的光催化剂的光催化活性。结果表明,Ag₂S/CoFe_1.95Y_0.05O₄降解甲基橙水溶液的一级动力学常数分别是Ag₂S和CoFe_1.95Y_0....     

Sn_(0.95)Ta_(0.05)P_2O_7/PTFE复合电解质的制备及中温电性能

先采用固相法制备Sn0.95Ta0.05P2O7电解质样品,再与适量聚四氟乙烯(PTFE)进行复合合成了有机-无机复合电解质聚四氟乙烯/Sn0.95Ta0.05P2O7。XRD测试表明PTFE/Sn0.95Ta0.05P2O7复合电解质衍射图谱与焦磷酸锡的JCPDS标准衍射图谱卡立方相Sn P2O7(JCPDS 00-029-1352)相同,还可以看出复合后新增加了PTFE的衍射峰,表明Sn0.95Ta0.05P2O7和PTFE复合没有发生反应生成新物质。SEM图可以看出样品致密性良好。采用电化学工作站对样品的中温电性能(40~200℃)进行了研究。结果表明,Sn0.95Ta0.05P2O7/PTFE在160℃下,电导率达到最大值为:1.7×10-2S·cm-1。     

TEX色谱分析条件的建立及热稳定性研究

为研究4,10-二硝基-2,6,8,12-四氧杂-4,10-二氮杂四环[5.5.0.05,903,11]十二烷(TEX)的稳定性,建立了TEX的高效液相色谱(HPLC)分析方法,采用TG-DTG和DSC研究了TEX的热行为,测定了不同升温速率(5、10、15、20和25K/min)下TEX的分解峰温,用Kissinger方法计算了TEX放热分解反应的表观活化能(Ek)和指前因子(A),用热力学方程计算了TEX放热分解反应的活化熵(△S≠)、活化焓(△H≠)和活化吉布斯自由能(△G≠)。结果表明,TEX对热较稳定,其热分解反应的△S≠、△H≠和△G≠值分别为501.03J/(K·mol)、432.48kJ/mol、145.26kJ/mol。     

Dielectric behaviour of (Mg0·95Ca0·05)TiO3 for application in terahertz resonator

Abstract

The 0·15 THz resonator based on the (Mg_0·95Ca _0·05)TiO₃ (abbreviated as 95MCT hereafter) ceramic was designed, and the dielectric property of 95MCT for application has been studied. La₂O₃ and Nb₂O₅ were selected as liquid sintering aids to lower the sintering temperature. X-ray diffraction patterns indicated that MgTi₂O₅ secondary phase could be effectively suppressed by La₂O₃ and Nb₂O₅ additions. When the Nb₂O₅+La₂O₃ codoping content was 0·25 wt-%, the ceramic could be densified at 1320°C and also has good dielectric behaviours of Q_f?=?69720 GHz (6·8 GHz), ?_r?=?20·18 and τ_f?=??7·56 ppm °C^?1. The terahertz resonator designed at 0·15 THz exhibited that with the increasing height of inner cylinder, the two modes’ resonance frequencies decreased.     

Pb(Mn1/3Sb2/3)0.05ZrxTi0.95-xO3压电陶瓷准同型相界附近的性能

以固态氧化物为原料,采用二次合成工艺制备锑锰锆钛酸铅三元系压电陶瓷。研究了组成为Pb(Mn1／3Sb2／3)0．05ZrxTi0．95-xO3(PMSZT)压电陶瓷的相组成、显微结构、电性能及温度稳定性。结果发现：该体系的准同型相界位于锆摩尔含量x=0．47附近;所有组成样品介电峰附近的相变都表现为弥散性相变特征;准同型相界附近谐振频率的相对变化率较小;在锆含量x=0．47的准同型相界处PMSZT综合性能达到最佳值：ε33^T／ε0=1420,d33=324pC／N,Kp=62％,Qm=2400,tanδ=0．0029,这可以满足大功率陶瓷材料的应用。     

Na0.5K0.44Li0.06Nb0.94Sb0.06O3无铅压电陶瓷的制备与性能研究

采用传统固相烧结法制备Na0.5 K0.44 Li0.06 Nb0.94 Sb0.06 O3无铅压电陶瓷,研究了烧结温度对陶瓷样品微观结构及电学性能的影响.研究结果表明:烧结温度在1020～1100℃范围内,样品均形成了单一的正交相钙钛矿结构,烧结温度对微观形貌和电学性能有较大影响;与纯KNN陶瓷相比,陶瓷的To-t和Tc均向低温方向移动;当烧结温度为1080℃时晶粒发育比较完全,To-t和Tc分别为45℃和345℃,同时表现出优异的电学性能:d33=200 pC/N,kp=0.365,tanδ=4.67％.     

Effects of poling state and pores on fracture toughness of Pb(Zr0·95Ti0·05)O3 ferroelectric ceramics

Abstract

Abstract

The effects of poling state and pores on the fracture toughness of Pb(Zr_0·95Ti_0·05)O₃ (PZT 95/5) ferroelectric ceramics were investigated. X-ray diffraction analysis and piezoelectric constant measurements reveal that the phase structures of PZT 95/5 ceramics change with the poling state, which significantly affects the fracture toughness. The poled PZT 95/5 ceramics demonstrate higher fracture toughness than the unpoled ceramics, and their fracture toughness significantly increases after the pressure depoling. As the porosity of ceramics increases with addition of poreformer during preparation, their fracture toughnesses all decrease accordingly either in poled state or unpoled state. The effect of pore size on the fracture toughness is subtle for the poled ceramics, but for the hydrostatic pressure depoled porous PZT 95/5 ceramics, their fracture toughness increases with the increase in pore size. A new stress model is proposed to explain the pore size effect on the fracture toughness of hydrostatic pressure depoled PZT 95/5 ceramics.     

流延工艺对BSZT-0.02MgO陶瓷微结构和性能的影响

采用溶胶凝胶法制备BSZT陶瓷粉,将Mg O粉体以2%摩尔比固相法掺入BSZT陶瓷粉中,研究不同流延工艺对Ba0.3Sr0.7Zr0.18Ti0.82O3(BSZT)-0.02Mg O陶瓷微结构和电学性能的影响。研究结果表明,适当的烧结温度和优化的流延成型工艺能有效改善陶瓷的电学性能,提高击穿强度和储能密度,本实验击穿强度达到233.33 k V/cm,储能密度达到1.539×106Jm-3。     

Mn离子掺杂对Ba_(0.2)Sr_(0.8)Zr_(0.18)Ti_(0.82)O_3陶瓷烧结和电学性能的影响

采用溶胶凝胶法制备x Mn-Ba0.2Sr0.8Zr0.18Ti0.82O3(BSZT)(x=0mol%、1mol%、2mol%、3mol%)的陶瓷粉末,以传统工艺制备Mn离子掺杂的BSZT陶瓷。研究Mn离子掺杂浓度对BSZT陶瓷烧结特性、物相结构、介电性能、击穿场强以及储能密度的影响。结果表明,Mn离子掺杂降低了BSZT陶瓷的烧结温度,同时降低其介电常数以及介电损耗,提高了击穿场强和储能密度。在1400℃下烧结的2mol%Mn离子掺杂BSZT陶瓷较未掺杂BSZT陶瓷的烧结温度降低了100℃,相对密度为96.3%;1 k Hz处介电常数约为497、介电损耗为3.6%;最大击穿场强为12.595 k V/mm;最大储能密度为0.374 J/cm3。     

新筛选菌种Sphingopyxis sp.USTB-05对微囊藻毒素的生物降解

A promising bacterial strain for the biodegradation of Microcystins (MCs) was isolated from Dianchi lake in China and identified as Sphingopyxis sp. USTB-05 by the analysis of 16s rDNA. Initial MC-RR of 42.3 mg&;#8226;L－1 was completely degraded by USTB-05 within 36 h, which was a relatively high biodegradation rate of MC-RR. With the cell-free extract (CE) of Sphingopyxis sp. USTB-05, MC-RR was biodegraded at a more rapid biodegradation rate compared with its strain, so that initial MC-RR of 42.3 mg&;#8226;L－1 was completely biodegraded within 10 h. During the bio-reaction of MC-RR catalyzed by CE, two intermediate metabolites and a dead-end product of MC-RR were observed on HPLC profiles and all of them had similar scanning profiles in the wavelength from 200 to 300 nm, indicating that the group of Adda in all products of MC-RR remained intact.