掺铁TiO_2光催化剂的水热法合成及其氧化降解溴甲酚绿

采用水热法合成了掺铁TiO_2光催化剂,利用扫描电子显微镜(SEM)、红外光谱仪(FT-IR)和X射线衍射(XRD)等对产物进行了表征。研究在紫外光(365 nm)照射下用合成的掺铁TiO_2催化降解溴甲酚绿的效果,分析了溴甲酚绿初始浓度、催化剂用量、掺铁量、光照时间等因素的影响;结果表明:自制的光催化剂晶体粉末由TiO_2微米球形成(球径约2.5μm),微米球由呈八面体的TiO_2纳米晶体自组装而成,八面体的三角形边长100~200 nm,晶体长度1.0~1.5μm;掺铁TiO_2晶体结构中含有大量羟基-OH(对应于3400和1636 cm-1的吸收),说明它应有较好的光催化性能。另外,2260 cm-1的吸收是N基的伸缩振动所致,而1126和520 cm-1则分别对应于Ti-O-C和Ti-O-Ti的弯曲振动;合成的掺铁TiO_2的晶型为锐钛矿型(即A-TiO_2);在8 mg·L-1的溴甲酚绿溶液中(p H=7),加入掺铁量7%(摩尔分数)的合成掺铁TiO_2粉末使其用量为0.6 g·L-1,18℃下紫外光照反应3 h,溴甲酚绿的降解率达到86.97%。     

银掺杂二氧化钛及其光催化性能研究

采用溶胶-凝胶法制备银掺杂二氧化钛光催化剂,通过XRD、SEM、FT-IR、TG-DSC 和UV-Vis等技术对其进行表征.以甲基橙为模拟污染物,考察催化剂的光催化活性,探讨煅烧温度和银掺杂量对光催化效率的影响.实验结果表明：银掺杂二氧化钛提高了二氧化钛在紫外光和可见光下的光催化活性;当Ag掺杂量为1.00%、煅烧温度为450℃、催化剂用量为0.05 g时,银掺杂二氧化钛光催化剂在可见光条件下降解4 h 后,降解率达到92.57%,是纯二氧化钛的4.51倍;紫外光条件下降解2 h达到84.54%,是纯二氧化钛的2.27倍.     

石墨烯—铁掺杂二氧化钛复合物制备及其光催化性能

以氧化石墨烯溶液为底水,采用一步法热水解工业钛液制备石墨烯-铁掺杂二氧化钛复合光催化剂。以亚甲基蓝光催化降解为目标反应评价其光催化性能,考察了氧化石墨烯溶液浓度、加料速率、升温速率等因素对其光催化性能影响。采用XRD、SEM、FT-IR、UV-vis DRS及XPS等技术对其进行表征。研究结果表明:掺杂铁以Fe~(3+)形式进入TiO_2晶格形成杂质能级,提高复合物可见光响应范围。石墨烯有利于光生电子传输,实现光生电子-空穴对有效分离,提高光催化量子效率。最佳水解条件为:石墨烯溶液浓度为0.03 mg/mL、加料速率为8 mL/min、升温速率为1.0℃/min。在此条件下,紫外光下及可见光下光催化效率分别为94.15%和80.89%。     

二氧化钛/石墨烯复合材料制备工艺研究

以工业偏钛酸为原料,经过酸解、中和制得正钛酸,然后采用喷雾干燥法制备正钛酸粉末,将制得的石墨烯粉末与其混合均匀,通过煅烧得到了二氧化钛/石墨烯复合材料。利用电子扫描电镜和X射线衍射仪对其结构和形貌进行了表征,并且开展了二氧化钛/石墨烯复合材料在紫外光照射条件下光催化降解甲基橙试验,确定了二氧化钛/石墨烯复合材料制备的最佳工艺参数。在二氧化钛与石墨烯质量比为100∶1,煅烧温度500℃,煅烧时间1 h的条件下制得的二氧化钛/石墨烯复合材料在1 h内对甲基橙的光催化降解率高达88.33%。     

La掺杂SiO_2/TiO_2纳米粉体的制备及其光催化性能

采用并流中和法制备了La掺杂的SiO2包覆TiO2纳米粒子,利用X射线衍射(XRD),傅立叶交换红外光谱(FT-IR),透射电镜(TEM)及紫外可见光吸收(UV-Vis)光谱对掺杂改性前后样品进行表征。以紫外光照降解甲基橙为测试体系,研究了La掺杂量及煅烧温度对SiO2/TiO2光催化性能的影响,并对其作用机制做了初步的探讨。FT-IR表明在包覆层和纳米TiO2颗粒之间的界面上形成了Ti-O-Si和Ti-OLa键,从而抑制了金红石相的形成,提高了热稳定性,和XRD分析结果一致,掺杂了La的SiO2/TiO2在800℃时金红石相的含量仍然比较低,和120℃时的含量相当;TEM照片显示改性后的TiO2团聚减小,粒度均匀。UV-Vis光谱分析显示La掺杂SiO2/TiO2的光响应范围拓宽至可见光区,其中光吸收红移最大的样品为3.0%La掺杂量的SiO2/TiO2,带隙能(Eg)由原来的2.98 eV降为为2.41 eV。光催化性能实验结果显示当La的摩尔掺杂量为3.0%时,其光催化活性最好,光照20 min,与未掺杂改性的TiO2相比甲基橙的光降解率提高了55.1%;另外,未掺杂TiO2煅烧温度对光催化影响显著,当温度由120℃增加为800℃时,光照25 min的降解率就由69%降为10.7%,而掺La的SiO2/TiO2煅烧温度对其光催化性能影响不大。     

工业钛液水热制备多孔二氧化钛光催化剂

以工业硫酸钛液为前驱体,采用水热法制备多孔二氧化钛,考察了煅烧时间对多孔二氧化钛结构和性能的影响.采用XRD、SEM、XPS、FT-IR和BET对样品进行表征,并以亚甲基蓝光催化降解体系评价其光催化活性.随着煅烧时间的延长多孔二氧化钛的光催化活性先增加后降低,其中以500℃煅烧lh所得样品活性最佳,1h对亚甲基蓝的降解...     

水热晶化制备多孔二氧化钛

以工业偏钛酸为原料,利用水热晶化制备多孔二氧化钛光催化剂,考察了不同水热晶化时间对多孔二氧化钛结构和性能的影响。采用XRD、SEM、FT-IR、N2低温吸附-脱附对样品进行表征,并以亚甲基蓝光催化降解体系评价其光催化活性。随着晶化时间的延长,多孔二氧化钛的光催化活性呈现先增大、后减小的趋势。140℃水热晶化2 h所得多孔二氧化钛的光催化活性最佳,反应1 h后对亚甲基蓝的降解率达81.18%,其比表面积SBET=99.59m2/g,孔体积VP=0.271 cc/g,平均孔径DBJH=3.809 nm,晶粒尺寸17.79 nm。     

(BiO)_2CO_3光催化剂的制备及性能

以硝酸铋和碳酸钠为原料在60℃条件下合成次碳酸铋((Bi O)2CO3)光催化剂。以亚甲基蓝、苯酚和甲基橙为光催化反应的模型化合物,考察了(Bi O)2CO3光催化剂在紫外光和可见光下光催化活性;以对苯二甲酸作为探针分子,结合化学荧光技术,研究了(Bi O)2CO3光催化剂表面羟基自由基的生成;添加各种清除剂,探究了(Bi O)2CO3光催化剂起主要催化作用的基团。结果表明:(Bi O)2CO3具有很好的可见光和紫外光光催化活性。紫外光照射下(Bi O)2CO3光催化剂比Ti O2光催化剂具有更高的光催化活性;在紫外光条件下(Bi O)2CO3和Ti O2光催化降解苯酚、甲基橙、亚甲基蓝的活性依次增高,并且,(Bi O)2CO3光催化降解甲基橙和亚甲基蓝的降解率分别达到94.3%,95.6%。可见光条件照射下,各种清除剂对(Bi O)2CO3光催化降解甲基橙的影响表明,反应体系所产生的·OH,h+,·O-2都起着很重要的催化降解作用,其中·O-2起着最主要的作用。     

铁掺杂钛基反蛋白石材料的性能表征及其可见光催化活性

采用溶胶凝胶法制备了不同掺杂比的铁掺杂二氧化钛反向蛋白石结构材料,通过扫描电镜,X射线能谱及紫外可见分光光度仪等对掺杂前后的样品进行比较,并采用罗丹明-B作为降解底物,对掺杂后样品在可见光下的光催化降解活性进行了研究.结果表明,铁掺杂后,样品的吸收带边发生红移,光响应区域扩展至550 nm,且样品中表面羟基氧的含量最高可提高到40%.铁掺杂样品的催化活性明显优于未掺杂的样品,其中掺杂比为10%的样品光催化降解活性最高,经可见光照射4 h后,其降解率可达85%以上.     

以偏钛酸为原料在室温离子液体中水热制备二氧化钛光催化剂

以偏钛酸作原料,用1-烯丙基,3-甲基咪唑氯([AMIM][Cl])室温离子液体,在温度160℃下水热制备了锐钛矿型的纳米二氧化钛.借助于X射线衍射仪(XRD),透射电子显微镜(TEM),和紫外.可见分光光度计(UV-Vis)等手段分别对所制备光催化剂的晶型、形貌、光学特性和光催化性能进行了表征.结果表明:所制备的二氧化钛光催化剂为锐钛矿型,其平均晶粒大小为18.4nm,颗粒为类椭球状,在可见光区存在一定的吸收,光催化性能测试表明所制备光催化剂降解亚甲基蓝的能力高于商业品P.25,并且在可见光照射下表现出了一定的光催化活性.     

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。     

显微维氏硬度测量不确定度评定

对显微维氏硬度测量不确定度进行评定，建立了不确定度计算的数学模型，确定了影响实验结果的各项因素，计算出了各因素的标准不确定度，得出结果的扩展不确定度，并给出最终测量结果的表达式。     

Concept of freedom of infection of animal flocks

Totally negative results of epidemiological investigation of random samples do not prove the absence of the infection as the pathogen may be restricted to only a few animals in the herd for a long time. The statement "absence of infection" is critical for such situations. The question is raised, whether the statement "absence of infection" should be generally avoided. Classification of herds and flocks according to the prevalence of the pathogen would be more valid for the implementation of control measures.     

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)     

Comparison of rates of infection of two methods of emergency ventricular drainage

The rates of infection of two methods of external ventricular drainage in use at Atkinson Morley's Hospital--namely, (a) percutaneous drainage with Rickham reservoirs and (b) tunnelled ventriculostomies--were compared in this retrospective review. Percutaneous drainage of CSF with Rickham reservoirs was associated with a 27% rate of infection as identified by positive microbiological cultures; tunnelled ventriculostomy catheters had a 10% infection rate. The difference in the infection rate between the two methods was statistically significant (P < 0.015). Other variables examined, including the age and sex of the patients and the reasons for ventricular drainage, were not associated with an increased rate of infection. Most infections from either method were caused by a coagulase negative staphylococcus. The average duration of ventricular drainage before identification of positive cultures was 5.7 days for Rickham reservoirs and 6.0 days for ventriculostomies.     

浅析《野草》的版画特征

鲁迅先生一生热爱美术作品,对版画中木刻兴趣尤甚.<野草>作为其"写心之作",亦呈现出一些与木刻版画一致的审美特征:一是具有木刻版画的色彩特征,多对比、多冷色,有阴郁的美感;二是具有木刻版画的力度特征,环境描写、人物刻画处处刀锋毕现,遒劲有力,有一种"力之美".     

四辊破碎机车刀架的改造

针对四辊破碎机车刀架车削中存在的几个问题,详细介绍了电动车刀架的结构和工作原理,建立主要设计参数的数学表达式,并进行适当的分析。改造后,这种电动车刀架运行平稳、可靠、方便、省力,取得了预期的效果。     

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。