TiO2-xNx薄膜的光催化性能及电子结构研究

在不同的氧气与氮气流量比条件下,利用射频磁控溅射技术在载玻片衬底上成功沉积了TiO2-xNx薄膜。采用亚甲基蓝染料为光降解污染物,考察了薄膜的光催化活性;检测了薄膜的XRD谱和透射光谱;并利用基于密度泛函理论的第一性原理计算了N掺杂锐钛矿相TiO2的能带结构及其在费米能级附近的电子态密度。结果表明,在氧气流量50sccm、氮气流量0.5sccm条件下沉积的TiO2-xNx薄膜的光催化活性最高;与纯TiO2样品相比,N掺杂TiO2样品的晶体结构没有发生改变,吸收边红移;N掺杂使TiO2的禁带宽度减小,电子态密度向低能量方向移动,从而使其光响应范围扩展,光催化活性增强。     

纳米锐钛矿型TiO2薄膜的制备及分析

采用反应磁控溅射法在玻璃衬底上制备锐钛矿相TiO2薄膜,研究了工艺条件中的氧氩流量比对薄膜润湿角的影响以及溅射气压对薄膜微观结构的影响。对不同氧氩流量比(分别为1/40,1/20,1/10和1/5)时制备的TiO2薄膜进行润湿角测量,润湿角照片显明:氧氩比1/5时薄膜润湿角可减小到8°左右,即提高氧氩比能增强TiO2薄膜的自洁净性能。X射线衍射(XRD)分析表明:当溅射气压降到1.0 Pa时,可以得到锐钛矿型TiO2薄膜晶体,0.5 Pa时的XRD图衍射峰更为明显。用分光光度计测量了TiO2薄膜的紫外吸收光谱,由光谱曲线上光吸收阈值与半导体带隙之间的关系计算出了TiO2薄膜的禁带宽度为3.42 eV,表明TiO2薄膜的吸收边出现了一定的蓝移。根据XRD图谱计算TiO2薄膜的晶粒尺寸,得到的薄膜晶粒尺寸在十几纳米左右,由此说明了TiO2薄膜吸收边发生蓝移的原因;按照锐钛矿相TiO2薄膜XRD图25.3°衍射峰对应的(101)晶面,由Bragg方程计算出其晶面间距为0.3521 nm,表明TiO2薄膜晶体发生了一定的晶格畸变。     

Nd_2O_3掺杂的HfO_2高k栅介质薄膜ALD制备及性能研究

采用原子层沉积技术(ALD)制备了Nd_2O_3掺杂的HfO_2高k栅介质薄膜(Hf-Nd-O),通过X射线光电子能谱(XPS)研究了薄膜中元素的成分、结合能及化学计量比,分析了Nd_2O_3掺杂后薄膜中氧空位浓度和界面层成分的变化;通过测量薄膜的光致发光(PL)图谱,比较了Nd_2O_3掺杂前后铪基薄膜中的氧空位浓度变化,分析了Nd_2O_3掺杂对HfO_2薄膜中氧空位浓度的影响;通过高分辨率透射电子显微镜(HR-TEM)研究了薄膜厚度及形态;制备了Pt/HfO_2(Hf-Nd-O)/IL/n-Si/AgMOS结构,应用半导体参数测试仪得到薄膜的电容-电压(C-V)和漏电流密度-电压(J-V)特性曲线。结果表明,Nd_2O_3掺入HfO_2薄膜后,整个铪基薄膜体系的氧空位减少,Hf-O键的结合能提高,Hf和O的原子比更接近理想的化学计量比(1∶2);在同样物理厚度与界面制备工艺条件下,Nd_2O_3的掺入使得MOS结构的饱和电容值提高,EOT降低,V_g=(V_(fb)+1)V时,Nd_2O_3掺杂的HfO_2薄膜的漏电流密度为8.7×10~(-3)A·cm~2,相比于纯HfO_2薄膜的3.5×10~(-2)A·cm~2有明显降低,电学性能整体得到提高。     

Fe离子注入二氧化钛复合薄膜制备及光吸收性能研究

采用溶胶凝胶法在石英基体上制备了纯TiO2薄膜,并通过离子注入方法对TiO2薄膜进行Fe掺杂改性以促进TiO2薄膜光吸收边红移,提高其光吸收性能。利用XRD、XPS及UV-vis对不同注入剂量的Fe掺杂TiO2复合薄膜的晶相结构、原子化学态以及光吸收性能进行了表征。XRD测试结果表明,溶胶凝胶法制得的TiO2薄膜为锐钛矿相,经Fe离子注入后,复合TiO2薄膜经退火后锐钛矿相消失,金红石相出现,因为Fe3+离子进入晶胞代替Ti4+,在TiO2基体形成铁的固溶体,结果氧空缺形成促进了TiO2从锐钛矿向金红石的转变;XPS测试结果表明,经过退火Fe在复合TiO2薄膜中以Fe和Fe3O4形式存在,说明Fe离子进入TiO2晶格取代Ti,但Fe及其氧化物晶体峰未在XRD上观测到,说明两者结晶程度不高,以非晶形态存在;通过对溶胶凝胶法制备的TiO2薄膜注入不同剂量Fe的复合薄膜的紫外-可见吸收光谱分析可知,由于复合薄膜中Fe3O4的存在,使复合薄膜紫外-可见光吸收边发生了红移,并随注入剂量增加红移增大,根据红移效果确定Fe的适宜注入剂量为1×1017 cm-2。     

叠层型Cu沉积TiO2复合薄膜的制备及光学性能

真空蒸镀法结合溶胶凝胶法成功地制备Cu-TiO23层复合结构薄膜.运用XRD,SEM,UV-vis等手段进行结构表征和光吸收性能测试.通过模拟可见光下制备样品对亚甲基蓝溶液降解率的变化,评定其光催化活性.结果表明:该法制备的复合结构薄膜,在未热处理时真空蒸镀的金属层为单质Cu.在723 K热处理后,沉积的Cu被氧化主要以Cu2O的形式存在,而TiO2为单一的锐钛矿晶型.823K保温2.0 h热处理后Cu2O进一步被氧化为CuO,同时出现了少量金红石型TiO2.由于Cu2O与CuO均为窄带隙的半导体,在可见光照射下会发生电子由价带向导带的跃迁,因此复合薄膜表现出明显的可见光吸收性能.降解实验的结果则表明:不同温度热处理后的复合薄膜均表现出较高的光催化活性,特别是723K热处理后的复合薄膜样品可见光催化活性最好,在可见光照射5.0 h后对亚甲基蓝溶液降解率接近100%.分析其原因认为,P型的Cu2O和CuO与n型TiO2半导体接触后,在其界面形成了纳米异质结的结合,其p-n结的内建电场抑制了光生载流予的再复合,提高了量子产率,因此使复合薄膜表现出较高的光催化性能.     

热处理对铜基碳纳米管复合镀膜结构和性能的影响

研究热处理工艺参数对铜基碳纳米管复合薄膜的微观结构和性能的影响,采用超声辅助脉冲电流复合电沉积法在不锈钢基板上沉积制备铜基碳纳米管复合镀膜,再将制备的复合薄膜在H2中进行热处理.利用X射线衍射谱仪(XRD)、场发射扫描电子显微镜(SEM)以及四探针电阻率仪等对热处理后的铜基碳纳米管复合镀膜进行了测试.结果表明,随着热处理温度和时间的变化,复合铜膜的结构、形貌及性能也相应变化;当热处理参数为400℃×2 h时,铜基碳纳米管薄膜的各项性能最佳.     

La~(3+)掺杂TiO_2的制备及光催化性能研究

采用溶胶-凝胶法制备了La3+掺杂的TiO2光催化剂(La/Ti原子比分别为1/100,2/100,3/100,4/100和5/100)。用比表面(BET)、X射线粉末衍射(XRD)、紫外可见漫反射光谱(DRS)和表面光电压谱(SPS)对所制备的光催化剂进行了表征。结果表明,La3+掺杂量为4%(La/Ti原子比)时所制备的TiO2具有最高电子-空穴分离效应。以甲基橙为模拟偶氮染料对所制备光催化剂的脱色性能进行考察,光催化脱色结果显示La3+掺杂量为4%时所制备的TiO2具有最高的光催化活性。     

氮气含量对射频磁控溅射法制备的AlN薄膜微观结构与力学性能的影响

用Ar气和N2气分别作为溅射气体和反应气体,采用射频反应磁控溅射法,通过调节工作气体(Ar气与N2气的混合气体)中N2的含量(体积分数)φ(N2),在硅(100)衬底上制备一系列六方结构AlN多晶薄膜,利用X射线衍射(XRD)、扫描电镜(SEM)、原子力显微镜(AFM)和纳米压痕仪等对薄膜特性进行测试与分析。结果表明,φ(N2)对AlN薄膜的择优取向、结晶性、沉积速率与力学性能的影响都十分显著,对薄膜的微观结构和表面粗糙度也有一定影响:随φ(N2)增大,薄膜的厚度和沉积速率逐渐减小,结晶性也发生显著变化;较高的φ(N2)有利于AlN薄膜沿(002)晶面择优生长;φ(N2)对AlN薄膜的硬度影响较大,而对弹性模量影响较小。实验制备的AlN薄膜具有良好的纳米力学性能,硬度平均值在12.0~29.3 GPa之间,弹性模量平均值在184.0~209.8 GPa之间。     

酸性条件下水浴沉积时间对硫化镉薄膜特性的影响

基于化学水浴法,以硫代乙酰胺为硫源、氯化镉为镉源、尿素为缓冲剂,在酸性条件下制备了CdS薄膜。采用台阶仪、X射线衍射仪、扫描电镜和紫外/可见光分光光度计,研究了酸性条件下化学水浴沉积时间对硫化镉薄膜厚度、结构、形貌和光学特性的影响。结果表明,沉积所得的CdS薄膜为六角纤维锌矿结构。随着沉积时间的延长,薄膜厚度和晶粒尺寸随之增大,带隙随之减小。当沉积温度为80℃,沉积时间为30min时,CdS薄膜可见光波段平均透过率接近80%。     

ATP-SnO2-TiO2复合光催化剂性能研究

以凹凸棒黏土(ATP)为基体,通过原位溶胶-凝胶工艺,制备出凹土基复合光催化剂(ATP-SnO2-TiO2)光催化甲醛。采用X射线衍射(XRD),透射电镜(TEM)等分析测试技术对复合体进行表征。考察制备条件对其物理结构和光催化性能的影响,并对不同光催化剂性能进行研究。结果表明,在凹凸棒黏土表面负载SnO2-TiO2后光催化性能得到明显提高,复合体中TiO2负载量为50%(质量比)、SnO2与TiO2质量比为1∶4、800℃煅烧的复合光催化剂活性最强,光照射3 h后对30 mg/L的甲醛溶液的降解率可达99%以上,显示出优异的光催化性能。     

转炉炉壳热应力分析

根据实际转炉建立实体模型。以有限元为手段,考虑了炉衬和炉壳材料的物性参数随温度变化的特点和炉衬与炉壳之间膨胀间隙,计算了转炉炉壳在温度载荷和炉衬膨胀压力同时作用下的热应力。所得结果可为转炉炉壳设计提供依据。     

Results of treatment of cancer of the cardia

Cancer of the cardia is traditionally discussed with cardiac cancer of the lower portion of the esophagus and upper gastric cancer invading the esophagus, and the specific characteristics of cancer of the cardia have never been clearly defined. We reviewed the outcome of 172 patients with adenocarcinoma of the cardia who had undergone radical surgery between 1949 and 1994 in the Division of Gastrointestinal Surgery of the Cancer Institute Hospital. The centers of the tumors were located within 2 cm above and below the boundary between the esophagus and the stomach, and their longitudinal diameter was less than 8 cm. We divided the patients into an early period (1949-1979; n = 79) and a late period (1980-1994; n = 93), and focused on the historical transition. There were no differences in patient gender or histology between the two periods. However, the late period was associated with fewer cases of esophageal invasion and shorter longitudinal diameter, as the age of the population advanced. The number of advanced cancers such as the localized and infiltrative type had decreased, and early cancer and early clinical stage had become more common, but despite the fact that the number of early cancers had increased, extended dissection, such as thoracic and paraaortic lymph node dissection, was performed more frequently. By clinical stage, the long-term outcome markedly improved in Stage I patient in the late period, and tended to improve in Stage II and III patients. This appears to have been attributable to the prevention of micrometastasis by extended dissection, although the number of early cancers is another major potential cause. There were no differences in the outcome of Stage IV patients between the two periods, and further advances in multimodality therapy must be awaited. The range of resection is basically proximal gastrectomy, and if there are adequate indications, the prognosis is favorable. In view of the status of lymphatic flow and lymph node metastasis, and long-term results, lateroaortic lymph node dissection is important. Since the number of early cancer patients has been increasing, if intraabdominal recurrence is prevented, intrathoracic lymph node dissection will contribute greatly to the outcome of such patients.     

焦炭热性能指标意义浅析

通过对焦炭在高炉内的历程及其变化规律的剖析,阐述焦炭热性能指标的意义,形象地把焦炭在高炉内的损耗分为三部分(M1,M2,M3)。指出M2对焦比及焦炭价格有一定的指导作用。     

Effect of antibiotics of chemotaxis of human leukocytes

The effect of 20 different antibiotics on chemotaxis by human neutrophils was studied. Human leukocytes incubated with chloramphenicol, rifampin, sodium fusidate, and tetracyclines in vitro showed markedly depressed migration. The mechanisms by which these antibiotics affect leukotaxis are discussed.     

Quality of life of relatives of mental patients

Usage of quality of life of psychiatric patients' relatives as the parameter of estimation of the quality of psychiatric care is considered. By means of standard questionnaire elaborated by the authors as well as by means of both individual and group conversations the quality of life was analyzed in 40 relatives which lived together with psychiatric patients. Different spheres of their life and difficulties (financial, social-psychologic, production) were examined in families with such patients. The defects of psychiatric care that had direct influence on the quality of life of the psychiatric patients' relatives are outlined.     

The effect of amount of possession of the trait of hostility on accuracy of perception of hostility in others.

Some theories of personality hold that an individual's perception of others is influenced by his own personality characteristics; more specifically, that a trait of low social value will be projected more into others, and that insight into the possession of these characteristics reduces this distortion. These 2 hypotheses were tested by having a group of college students rate each other (including themselves) on degree of friendliness or hostility. Agreement with group rating about self yielded the insight score. In general, the hypotheses were supported; the "friendly" Ss were most accurate in their perception of others, and insight was positively associated with accurate perception. From Psyc Abstracts 36:04:4HL16M. (PsycINFO Database Record (c) 2010 APA, all rights reserved)