直流磁控溅射法在PET基板上制备AZO薄膜

室温下用直流磁控溅射法在PET塑料基板上制备氧化锌薄膜及掺铝氧化锌AZO(ZnO∶Al)薄膜.通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、四点探针仪、霍尔效应仪及光谱仪等装置,考察了氧分率、溅射功率及铝掺杂量等工艺参数对薄膜微观结构和光电性能的影响.结果表明:AZO薄膜晶体结构为纯ZnO的六角纤锌矿结构.随着Al掺杂量增多,AZO薄膜导电性增加,透光率下降.在氧分率为8.2％,ZnO(40 nm)/Al(6 nm)三层膜条件下,得到电阻率为5.66×10-2Ω·cm,可见光范围内透光率约为80％的AZO薄膜.     

田口法研究3Y-TZP/TiN导电陶瓷材料最佳化制程

实验用田口法研究了添加30wt%氮化钛的钇稳定氧化锆基陶瓷材料(3Y-TZP/TiN)制造工艺. 选择烧结方式、TiN粉末振荡时间、第一阶段保温时间及第二阶段烧结温度四个工艺参数作为控制因子, 设计L₉正交表进行实验规划. 烧结后, 检测试片断裂韧性、抗弯强度、硬度、相对密度及电阻值. 最后通过变异数分析找出最佳参数, 再进行实验验证. 本研究得到的最佳化烧结工艺为: TiN粉末振动8 h, 采用两步烧结法, 第一阶段烧结温度1450℃, 不保温, 第二阶段烧结温度1150℃, 保温20 h. 结果显示, 采用该工艺得到了抗弯强度平均值为736.75 MPa、断裂韧性为7.545 MPa·m^1/2的氧化锆基导电陶瓷材料. 研究发现, 第一阶段保温时间对断裂韧性的影响程度最大, 其次依次为烧结方式、TiN粒径大小及第二阶段保温温度. 断裂韧性的微结构影响因子为四方相与单斜相数量的比值, 当此值达到最高时, 断裂韧性也达到最高值为9.275 MPa·m^1/2. 另外, 添加30wt% TiN的氧化锆电阻率平均值为3.26 m?·cm, 可以进行电火花加工.     

THE EFFECTS OF SOYBEAN PROTEIN-DERIVED HYDROLYSATE ON LIPID METABOLISM IN RATS FED A HIGH CHOLESTEROL DIET

This study was performed to investigate the effects of the peptic undigested fraction derived from soybean protein hydrolysate (UDSP) on lipid metabolism in rats fed a cholesterol‐enriched diet (1%). Eighteen male Wistar rats‐weighing 205–235 g were randomly divided into three groups: the control group (20% casein), U2 (18% casein + 2% UDSP), and U5 group (15% casein + 5% UDSP). After 4 weeks, rats were sacrificed, and the lipid profiles of the plasma, liver, and feces were determined. Body weight gain, daily food intake, and liver weight showed no differences among the groups, but the feeding efficiency ratio in the U5 group was significantly lower than that in the other groups (P < 0.05). There were no changes in plasma cholesterol, LDL‐C, HDL‐C, and liver cholesterol levels in each group. However, the U5 group showed a significantly lower VLDL‐C compared to the control and U2 groups. In addition, the plasma and liver TG content were lower in the U2 and U5 groups than in the control group (P < 0.05). Moreover, the fecal bile acid and total neutral steroid excretions were higher in the U2 and U5 groups (P < 0.05) compared to the control group.     

Effect of reactive ion etching and post-etching annealing on the electrical characteristics of indium-tin oxide/silicon junctions

Indium tin oxide (ITO) films were deposited onto p-type Si wafers with radio frequency (r.f.) magnetron sputtering. The effect of the silicon surface treatment with reactive ion etching (RIE) on the current–voltage (I–V) and capacitance–voltage (C–V) characteristics of the ITO/Si junction are investigated. When the Si substrate is etched by RIE prior to the deposition of ITO film, the I–V characteristics of the ITO/p-Si junction transfer from an ohmic contact for the unetched-Si to a rectifying contact for the etched Si. In addition, the barrier height, ideality factor, and series resistance increase with increasing etching power. This is attributed to the net positive ion charge and defects on the damaged surface. Thermal annealing can eliminate the damage caused by RIE. The I–V curves of ITO/etched p-Si become more ohmic as samples are annealed in N2 at 300 °C. Secondary ion mass spectroscopy (SIMS) depth profiles indicate that some impurity defects migrate and/or disappear after post-etching annealing. © 1998 Chapman & Hall     

Review of various Types of Flow Maldistribution in Heat Exchangers

The types of maldistributions and their causes are discussed. Where possible, means of-avoiding or curing the problem are given. While the performance loss is often small, there are associated mechanical problems that can be severe.     

Effect of MgO addition on the electrical transport properties of highly Sb-doped BaTiO3 ceramics

BaTiO3 ceramics doped with Sb donors and Mg acceptors have been fabricated. The lattice constant ratio c/a and the Curie point Tc decrease with increasing Sb concentration. The minimum room temperature resistivity min of the codoped BaTiO3 occurs at a composition of 0.9 mole% Sb2O3-1 mole% MgO as compared to the literature reported min at 0.3 mole% antimony for the Sb2O3-doped BaTiO3. The Mg2+ ion acts as an acceptor in the BaTiO3 ceramics, which compensates the donor contribution from Sb3+ and shifts the doped-BaTiO3 semiconducting region to higher antimony content. The calculated donor concentration confirms the compensation effect of Mg acceptors over Sb donors. The temperature dependence of both barrier height and dielectric constant of specimens is discussed. © 1998 Chapman & Hall     

Measurement of Residence Time Distribution of Fluid and Particles in Turbulent Flow

Residence time distribution (RTD) of fluid and particles was measured in the holding tube of an aseptic processing system. A unique injector device instantaneously injected a large number of particles at one time without interruption of flow. A fraction collector device sampled exiting fluid at 1-sec intervals. Exiting particles at specific lapsed times from injection, were counted from those collected. RTD of fluid was determined by dye injection. RTD of fluid and particles under turbulent flow fitted a normal distribution function. Mean residence time of fluid was 0.975 times that calculated from volumetric flow rate with standard deviation ± 4.16%. Mean residence time of particles was 1.032 times that of the fluid, standard deviation was ± 4.62%.     

田口-灰关联法应用于Inconel 718微放电铣削参数最佳化(英文)

应用田口-灰关联法对Inconel 718微放电铣削多重质量特性如电极消耗率、材料去除率和扩口量进行最佳化,分析放电电流、脉冲时间、休止时间和极间间隙对加工Inconel 718之电极消耗率、材料去除率和扩口量的影响。实验结果表明,以最佳微放电铣削参数进行加工,其电极消耗率由5.6×10-9mm3/min降低到5.2×10-9mm3/min,材料去除率由0.47×10-8mm3/min增加到1.68×10-8mm3/min,扩口量由1.27μm降低到1.19μm。研究结果显示,应用田口-灰关联法,可以改善微放电铣削多重质量特性。     

CHARACTERISTIC OF (100)-TEXTURED (PbxSr1 −x)TiO3 THIN FILMS USED FOR DRAM AND TUNABLE DEVICE APPLICATION

ABSTRACT

The (Pb_xSr_1-x)TiO₃ (PST) thin films were deposited on LaNiO₃ (LNO(1 0 0))/ Pt/Ti/SiO₂/Si substrates electrode by RF-magnetron sputtering using three different Pb target composition ranging from 32.5%～37.5% and different process condition. Structural and dielectric properties of the PST thin films for tunable microwave and DRAM application were investigated. The PST thin films deposited at 400°C show higher dielectric constant than those post-annealed at 600°C because of better crystallization. The former also have lower leakage current around 10^?8 A/cm² up to applied field of 350 kv/cm, which is suitable for DRAM application. On the other hand, the post-annealed PST thin films have satisfactory tunability around 58% and figure of merit around 30, which are more suitable for microwave device application.