锐钛型纳米TiO2光催化降解甲醛性能研究

概述了纳米TiO2光催化降解甲醛的机理。着重探讨了乳胶漆中TiO2含量、粒径、晶型含量及反应温度对TiO2光催化降解甲醛的性能影响，以及甲醛质量浓度和反应时间对甲醛降解速率的影响。     

基于正交设计与BP神经网络优化制备Cu-Ce/TiO_2的预测模型

采用过渡金属Cu和稀土金属Ce对TiO2进行改性。为获取高效的甲醛气体去除率,运用正交实验设计结合BP神经网络优化TiO2的改性方案。以Cu-Ce掺杂负载量、Cu-Ce摩尔比和烧结温度为正交实验设计因子,每个因子各取3个水平,以光催化甲醛气体的降解效率为目标因子,编制3因素4水平正交设计表。结合BP网络强大的函数拟合功能,以正交设计表中3因素为网络输入层,以光催化甲醛气体的降解效率为网络输出层,建立BP神经网络优化模型,并通过该模型进行预测和优选,得到最佳的活性炭改性方案。即Cu-Ce掺杂负载量为2.92%、Cu-Ce摩尔比为1∶1和烧结温度为517℃。此时光催化甲醛气体的降解效率为61.60%,与预测值59.47%的相对误差为3.46%。     

纳米二氧化钛光催化作用降解甲醛的研究

主要讨论了以锐钛矿型纳米二氧化钛为主体原料制成的空气净化喷雾剂降解甲醛的实验，结果表明此剂对甲醛能起到良好的降解效果。还考虑二氧化钛不同晶粒尺寸和不同晶体类型、甲醛不同初始浓度以及不同光源对甲醛降解的影响，并分析了原因。     

La-TiO2中性水溶胶光催化性能

以偏钛酸为原料,制备了锐钛矿型纳米TiO2中性水溶胶,采用XRD、SEM、TEM、吸收光谱以及光电流响应等对TiO2水溶胶进行表征.结果发现,TiO2粒径约为11.6 nm,稀土元素La掺杂,使得水溶胶的吸收光谱阙值红移至545 nm,可见光响应能力明显增强.光催化降解试验表明,溶胶对甲醛具有快速降解能力,当甲醛浓度≤3×10-6时,24 h可以降解至国家标准范围以内,但降解过程受环境湿度影响明显.     

温度和湿度对Nafion膜氢传感器性能的影响

系统研究了以Nafion112膜为电解质的氢传感器在不同工作环境下的氢敏感性能.结果表明,以Nafion112膜为电解质的氢传感器对氢具有很好的敏感性,可以实现微量氢气泄漏的快速检测.该传感器在氢气体积分数为(500～3000)×10^-6时的响应电压与氢气体积分数的对数呈线性关系,为标定不同环境下氢气含量与传感器响应电压的对应关系提供了依据.在相同湿度条件下,传感器响应电压随温度的升高而下降.湿度对传感器响应电压的影响与温度相关:温度较低时,响应电压随湿度的增加而下降;温度较高时,响应电压随湿度的增加而升高.     

自养小球藻培养条件的优化

在无菌条件下,对影响自养小球藻生长的主要因素进行优化.实验表明,优化结果对小球藻的生长有显著影响.通过正交试验和单因素实验得到了以BG-11培养基为基础的优化培养条件:Ha2CO3质量浓度为0.02 g/L、初始pH值为7、N/P为30、接种量为5%、温度25 ℃、光照强度8 800 lx.该优化条件有效地提高了自养小球藻的生长速率.     

玉米交联淀粉的制备研究

[目的]探讨甲醛用量、pH值、反应温度、反应时间对玉米交联淀粉交联度(即沉降积)的影响.[方法]以玉米淀粉为原料,甲醛为交联剂,制备玉米交联淀粉.[结果]确定最佳工艺条件为:甲醛与淀粉的质量比为0.020、反应时间为1 h、反应pH值为9.0、反应温度为42.5 ℃,所制备的交联淀粉沉降积为2.7 ml.[结论]该试验筛选出了制备玉米交联淀粉的最佳工艺条件,该法具有工艺简单、快速、高效等特点.     

稀土上转光剂(Y3Al5O12∶Er^3+)复合TiO2光催化剂的制备及其催化性能的研究

采用溶胶-凝胶法、高温煅烧法和超声分散法制备了Y3Al5O12∶Er^3+/TiO2复合光催化剂,并对制备的样品进行了XRD和SEM表征。利用次甲基蓝水溶液模拟有机污染水,对比了单一TiO2,上转光剂Y3Al5O12∶Er^3+以及Y3Al5O12∶Er^3+/TiO2复合光催化剂的催化活性。同时讨论了煅烧温度、煅烧时间、光照射时间、光照强度以及光催化剂用量等因素对光催化剂性能的影响。结果表明,煅烧温度为550℃、煅烧时间为90 min,照射时间为150 min,光照强度为1.0 mW/cm2和催化剂的量为1.00 g/L时,Y3Al5O12∶Er^3+/TiO2复合光催化剂降解次甲基蓝表现出了最佳的催化效果。     

含氰废水光化学降解的试验研究

对含氰废水进行了不同自然光照条件下的降解模拟试验研究。试验结果表明,光照越强,氰化物降解越快;温度、pH值、搅拌速度对自然光降解氰化物影响较大,温度越高pH值越小、搅拌速度越高．氰化物降解越快,去除率越高。同时,还对比试验了紫外光照条件下的氰化物降解,结果表明,紫外光对氰化物的降解速度远高于自然光。用溶胶凝胶法制备的TiO2为微细粉末状晶体,在光氧化舍氰废水中催化效果较好。在最佳试验条件下,降解质量浓度为14．81mg／L的含氰废水需150min即可达到排放标准。对降解反应的动力学进行了分析,结果表明,光化学降解氰化物为一级反应。     

碳化法制备SiO_2包覆CeO_2-SiO_2共沉淀内核复合材料降解甲醛性能研究

采用碳化法制备氧化铈无机改性水合二氧化硅粉体材料并对其甲醛吸附降解性能进行研究。通过氯化铈与水玻璃自发形成共沉淀内核,继以碳化法形成二氧化硅外壳加以包覆,制备出一种复合材料粉体。经检测,该改性二氧化硅可以对甲醛有吸附和光催化降解作用;通过XPS对共沉淀内核测试,确定Ce元素氧化物为CeO_2;用扫描电镜对内核形貌观察,共沉淀内核为CeO_2纳米颗粒镶嵌在SiO_2骨架的共沉淀结构,该结构可以提高氧化铈颗粒接触紫外线的有效体积,达到提高光催化降解甲醛的性能。     

环境条件对质子交换膜燃料电池性能的影响

研究了不同环境温度、湿度条件下小功率质子交换膜燃料电池(PEMFC)堆的性能。结果表明:环境温度、湿度对PEMFC堆的性能有很大影响,随着相对湿度的增加,PEMFC堆的最大输出功率显著提高;当相对湿度小于30%或者当环境温度降至10℃以下时,PEMPC堆的性能严重下降。

     

A system for inducing hyperthermia in sheep

A system that produces hyperthermia in pregnant sheep in a consistent and reproducible manner was designed. The experimental approach was through control of ambient temperature and relative humidity in a closed chamber; the sheep was unable to lose its metabolic heat in an environment of 42 degrees C and 75% relative humidity. This system resulted in a steady and progressive temperature rise of 2.5 degrees C in the maternal abdominal aorta in 120 +/- 17 min.     

纳米二氧化钛粉体的光催化性能

以紫外灯为光源,采用TiO_2悬浮体系,利用分光光度法,研究了各种实验条件对光催化效果的影响。结果表明:光强、甲基橙的初始浓度、TiO_2的浓度和晶型、溶液pH以及掺杂离子等对降解效率都有较大的影响。     

Factors affecting pain intensity in a pain model based upon tonic intranasal stimulation in humans

OBJECTIVE: The present publication describes an inflammatory pain model based on an air-stream introduced in the nasal cavity. The aim of the present study was to investigate the influence of flow, humidity and temperature of the air-stream on the intensity of the evoked pain sensations. METHODS: Six healthy volunteers participated in the study. Pain was produced by a stream of air introduced to the nasal cavity at different flow rates (5, 6 and 81/min), humidity (20 and 80% relative humidity) and temperature (16, 24, and 32 degrees C). The evoked pain was quantified by means of visual analogue scales. RESULTS: The air-stream induced a dull and burning painful sensation. The intensity of pain was found to be related to the air-stream's humidity and temperature. Specifically, a dry air-stream (20% relative humidity) evoked significantly stronger pain than a humidified air-stream (80% relative humidity). Pain was significantly greater at a temperature of 32 degrees C than at 24 degrees and 16 degrees C, while the temperatures of 16 and 24 degrees C did not differ with respect to pain intensity. In contrast, a tendency towards stronger pain produced by a flow of 81 compared to that with 51 could not be statistically justified within the present study. CONCLUSIONS: The non-invasive pain stimulus was found to be easily applicable and the evoked pain sensation could be modified by variation of humidity and temperature of the air-stream.     

Luminescence and Preparation of LED Phosphor Ca8Mg(SiO4)4Cl2:Eu2+

Calcium magnesium chlorosilicate doped by europium, Ca8Mg(SiO4)4Cl2:Eu2 , was prepared by the solid state reaction at high temperature. The compound obtained is pure Ca8Mg(SiO4)4Cl2 phase with cubic structure. Its average particle size is 5 μm, and it has good dispersity and morphological form. The excitation spectrum of Ca8Mg(SiO4)4Cl2:Eu2 is a wide band, which covers from 270 to 480 nm. The emission spectrum is also a wide band peaked at 510 nm. The luminescent intensity reaches to the maximum when the concentration of Eu2 is 2%. The wavelength of emission and excitation of the phosphor with various Eu2 contents keeps constant. This spectrum range matches violet and blue LED chips very well, and its strong luminescence intensity is suitable for a green phosphor of tricolor phosphor of white light LED.     

Limbus-based vs fornix-based conjunctival flap in combined glaucoma and cataract surgery with adjunctive mitomycin C

1. The effects of relative humidity on growth rate and thermoregulation at high ambient temperature were evaluated in turkeys. Male turkeys were exposed to ambient temperature (Ta) of 35 degrees C and relative humidity (RH) of 40% to 75% and 50% to 85%, at ages of 13 to 19 weeks (trial 1) and 10 to 15 weeks (trial 2), respectively. 2. Body weight and food intake in both trials increased as RH increased up to 70% to 75%. When RH increased further to 80% to 85% (Trial 2) both body weight and food intake declined significantly. 3. Blood CO2 partial pressure (pCO2) did not change significantly at different RHs (trial 1). However, in trial 2 it dropped significantly at 80% to 85% RH. This response coincided with an increase in blood pH. 4. The effect of RH on body temperature (Tb) was not significant in either trial. 5. Triiodothyronine (T3) concentrations increased with the increase in RH up to 70% to 75% RH (trials 1 and 2). A significant decrease was observed when RH was further increased to 80% to 85% RH (Trial 2). Positive linear correlations between T3 and food intake or weight gain were observed in both trials. 6. The results indicate that turkeys can thermoregulate efficiently in the face of extreme changes in RH and that only at high RH (above 75%) did the performance of turkeys deteriorate.     

Fluorescent lamp promoted formaldehyde removal over CeO2 catalysts at ambient temperature

Exploring an alternative strategy with high efficiency and low cost to abate formaldehyde (HCHO) in indoor environment, is of increasing significance for people's health. CeO₂ catalysts prepared by hydrothermal, precipitation and calcination methods were investigated for HCHO removal at ambient temperature. It is found that indoor fluorescent light visibly boosts the catalytic performance of CeO₂ catalysts for HCHO decomposition at ambient temperature. Among the CeO₂ catalysts, CeO₂ prepared from hydrothermal method (CeO₂–H) exhibits a superior catalytic performance and an excellent durability by eight recycle times. Based on the characterization and analysis, the excellent catalytic performance of CeO₂–H is mainly contributed by its abundance of surface oxygen vacancies, and photogenerated electrons and hole activated by fluorescent light. This work shows a potential practicability in HCHO pollution elimination by taking full advantage of the existing lighting in indoor environments.     

Fluorescence in situ hybridization analysis of chromosome 1p36 deletions in human MYCN amplified neuroblastoma

Artificial illumination is an important factor in the management of layers. In this study, a new monochromatic light system was developed for egg layers. Prelaying pullets (Lohmann) were marked and housed in nine light and temperature control rooms (15 battery cages, 3 hens per cage; n = 45), divided into three light treatments: 0.1 and 0.01 W/m2 light intensity using light emitting diode (LED) lamps and 0.1 W/m2 using mini-fluorescent bulbs (PL) (control). In each of the LED rooms, three wavelengths were tested: 560 (n = 9), 660 (n = 9), 880 (n = 6), and 660 intermitted lighting (15 min light 45 min dark, 660IN) (n = 9). Birds were exposed to 12 h light and 12 h of darkness using PL lamps. At 21 wk of age, the light period was increased to 12.75 h by using 5.5 h of LED lamps and 7.25 of PL light source for Groups 1 and 2, the third group received 12.75 h of PL light. Until 28 wk of age, light hours increased by 0.5 h/w using LED light for Groups 1 and 2 and PL source for the third group, reaching 16 h of light at 28 wk of age. Egg production and feed consumption were recorded daily; egg components were recorded weekly for 10 mo. A significant reduction in egg production was observed in all 880nm groups; no differences in egg production and quality were found in the other groups. Feed consumption was significantly lower by 7% in all 0.01 W/m2 groups. We suggest that an important reduction in rearing costs of laying hens may be obtained by using this system.     

Photoluminescence Characteristics of Gd2Mo3O9 ： Eu Phosphor Particles by Solid State Reaction Method

Eu^3＋-doped Gd2Mo3O9 was prepared by solid-state reaction method using Na2CO3 as flux and characterized by powder X-ray diffractometry. According to X-ray diffraction, this material belonged to a tetragonal system with space group I41/α. The effects of flux content and sintering temperature on the luminescent properties were investigated with the emission and excitation spectra. The results showed that flux content and sintering temperature had effects on the luminescent properties, the optimized flux content and the best temperature was 3 % and 800 ℃ respectively. The excitation and emission spectra also showed that this phosphor could be effectively excited by C-T band （280 nm）, ultraviolet light 395 nm and blue light 465 nm. The wavelengths at 395 and 465 nm were nicely fitting in with the widely applied output wavelengths of ultraviolet or blue LED chips. Integrated emission intensity of Gd2Mo3O9 ： Eu was twice higher than that of Y2O2S ： Eu^3 ＋ under 395 nm excitation. The Eu^3＋ doped Gd2Mo309 phosphor may be a better candidate in solid-state lighting applications.