Er3+∶YAlO3/Fe掺杂TiO2复合物的制备及光催化活性研究

对TiO2半导体材料进行改性,分别通过溶胶凝胶、超声波分散和溶液沸腾的方法合成了Er3+∶YAlO3/Fe掺杂TiO2复合物光催化剂,并且采用XRD和SEM进行表征,研究了各种因素在太阳光照射下降解酸性红B的催化活性,也考察了Er3+∶YAlO3的包覆量、Er3+∶YAlO3/Fe掺杂TiO2的量、太阳光照射时间、酸性红B的初始浓度和氯化钠浓度等其降解过程用UV-Vis光谱进行检测。实验结果表明,加入上转光剂之后降解率大幅度增加,改性后的光催化剂可以有效地降解染料废水。     

YAlO3/SnO2-TiO2复合物的制备及降解有机污染物的应用

以实验室合成YAlO3/SnO2-TiO2复合物作为催化剂,以酸性红B溶液模拟有机污染水,并用扫描电镜对YAlO3/SnO2-TiO2进行表征,研究了处理温度、处理时间、照射时间及YAlO3/SnO2-TiO2对酸性红B降解率的影响,同时也对不同染料进行了研究。结果表明,在YAlO3/SnO2-TiO2催化剂作用下可见光降解酸性红B的效果明显优于单纯TiO2或SnO2催化时的效果。     

上转光剂Er3+∶YAlO3复合物的声催化活性研究

通过溶胶凝胶的方法制备了上转光剂Er3+∶YAlO3,然后通过超声分散和溶液沸腾的方法合成了Er3+∶YAlO3/TiO2-CdS复合物光催化剂。利用X射线粉末衍射(XRD)和扫描电镜(SEM)技术对Er3+∶YAlO3和Er3+∶YAlO3/TiO2-CdS复合物进行了表征。以酸性红B染料水溶液作为模拟污染物,通过可见声催化降解程度评估Er3+∶YAlO3/TiO2-CdS复合物催化活性,并且比较了Er3+∶YAlO3/TiO2和Er3+∶YAlO3/CdS光催化活性。最后,对Er3+∶YAlO3上转光剂的原理和Er3+∶YAlO3/TiO2-CdS复合物的声催化机理进行了讨论。     

铝酸镱掺杂二氧化钛复合物的制备及光催化降解有机染料的研究

采用溶胶-凝胶法制备YbAlO3/TiO2复合物,在可见光的照射下,考察了孔雀石绿的降解效果,并利用X-射线衍射(XRD)对光催化剂进行了表征,同时讨论了影响孔雀石绿降解的主要因素:YbAlO3/TiO2的煅烧温度、煅烧时间以及用量、可见光照射时间等。实验结果表明,YbAlO3掺杂TiO2在150 min孔雀石绿的降解率达到96.40%,表现出更好的光催化活性。     

YFeO_3/TiO_2-SnO_2声催化剂的制备及降解酸性红B的研究

采用溶胶凝胶法制备了YFeO3和超声分散法制备了YFeO3/TiO2-SnO2和YFeO3/TiO2复合物,通过酸性红B的声催化降解来评价复合材料的催化活性,并与单一TiO2的声催化性能进行了比较。结果表明,YFeO3/TiO2-SnO2的声催化活性明显优于单一TiO2或YFeO3/TiO2。并且考察了声催化剂的处理温度和用量,超声照射时间和染料初始浓度等因素对酸性红B降解率的影响。     

钇掺杂TiO2/膨润土纳米复合光催化剂的性能研究

以膨润土为载体,钛酸四丁酯和氯化钇为原料,采用溶胶-凝胶法制备钇掺杂TiO2/膨润土纳米复合光催化剂,运用X射线衍射(XRD)、差热-热重(DTA-TG)和红外光谱(IR)对纳米复合光催化剂进行了表征,在太阳光照射下,通过染料酸性红B的降解反应,考察其光催化活性。实验结果表明:钇掺杂TiO2已进入膨润土层间,经500℃热处理后,在膨润土表面有锐钛矿型TiO2生成,并结合牢固;适量的钇掺杂降低了TiO2粒子的粒径,显著提高了光催化降解有机物的活性;随着光照时间的延长,染料酸性红B的特征峰510nm强度逐渐减弱,2h后彻底消失,酸性红B的去除率达97.38%。     

掺Mo~(6+)附Ag纳米TiO_2在可见光下降解酸性大红3R

通过溶胶-凝胶法结合光催化还原法制备掺Mo6+附Ag的TiO2纳米颗粒,并在可见光下对酸性大红3R进行降解实验,研究其在可见光下的催化活性,并与纯TiO2、仅掺Mo6+或仅附Ag的TiO2进行对比。进一步讨论在可见光照射下掺杂量、焙烧温度等因素对掺Mo6+附Ag纳米TiO2降解性能的影响。结果表明:可见光下Ag/Mo6+/TiO2比纯TiO2、仅掺Mo6+或仅附Ag的TiO2显示出更高的活性,这是因为金属Mo6+的掺杂和贵金属银的沉积使二氧化钛的吸收带边发生红移,拓宽了可见光的响应范围;Ag/Mo6+/TiO2催化剂的催化活性最高时的Mo6+掺杂量为4.5%,银的附着量为2%。焙烧温度为500℃,这种掺Mo6+附Ag纳米TiO2对酸性大红3R的降解率可达87.6%.     

Cu掺杂对硫化镍精矿制备高效异相类Fenton催化剂(Ni,Mg, Cu)Fe2O4的影响

以硫化镍精矿为原料,采用共沉淀–煅烧法成功制备出Cu掺杂尖晶石铁氧体(Ni, Mg, Cu)Fe₂O₄异相类Fenton催化剂。利用X射线衍射(XRD)、扫描电子显微镜(SEM)及X射线光电子能谱(XPS)等手段系统研究了Cu掺杂量对所制备产物微观结构、形貌及催化性能的影响;确立了最优催化体系为光助类Fenton催化体系“(Ni, Mg, Cu)Fe₂O₄催化剂/H₂O₂/可见光”,揭示了Cu掺杂对(Mg, Ni)Fe₂O₄催化活性的增强机制。结果表明:在选定的实验条件下,制备得到的产物均为纯相立方尖晶石铁氧体。当Ni与Cu摩尔比为1∶1时,合成的(Ni, Mg, Cu)Fe₂O₄在可见光照180 min条件下对质量浓度为10 mg?L?1的罗丹明B(RhB)溶液的降解率可达94.5%。究其主要原因为:随着Cu掺杂量的增加,占据(Ni, Mg, Cu)Fe₂O₄八面体位的Fe3+和Cu2+的相对含量增加,即裸露于铁氧体表面的Fe3+和Cu2+数量增多,以及两者的协同作用,加速了羟基自由基(·OH)反应的发生,最终使得RhB溶液的降解效率从73.1%提高至94.5%。      

WO3/TiO2薄膜光催化降解ARB性能研究

采用溶胶-凝胶法,在玻璃珠表面涂覆均匀透明的WO3/TiO2薄膜,并制成光催化反应器对水溶液中酸性红B（ARB）的光催化降解进行了研究。采用XRD对催化剂进行了表征,讨论了催化剂的组成、煅烧温度、酸性红B的起始浓度、pH值、光照时间等因素对光催化反应活性的影响。结果表明：当ω（WO3）=4.0%,煅烧温度为500℃,[ARB]=20 mg.L^-1,pH=7.1,光照时间为8 h时,酸性红B的脱色率可达94.8%。     

F掺杂可见光催化剂Bi2MoO6的制备及其增强的光催化性能

通过简单的水热法成功合成了氟掺杂Bi2MoO6光催化剂,通过XRD、TEM、FT-IR、DRS等手段对合成产物进行了表征,研究了氟掺杂对Bi2MoO6的结构和光催化活性的影响。紫外可见漫反射光谱显示,掺氟的光催化剂在可见光区域具有更强的吸收。可见光照射下对罗丹明B的光催化降解实验表明,F/Bi2MoO6复合催化剂展示了增强的光催化活性。当F/Mo比为0.3时,复合催化剂表现出最高的光催化活性。这可能是由于F掺杂使催化剂的光生电子和空穴的再复合率降低,提高了催化剂的光量子效率,增强了催化剂的活性。     

Language, context, and speaker effects in the identification and discrimination of English /r/ and /l/ by Japanese and Korean listeners

Japanese and Korean listeners' identification and discrimination of English /r/ and /l/ were compared using a common set of minimal pair stimuli. The effects of speakers (two native speakers of Australian English), position of the contrast within the word (word initial, initial consonant cluster. and medial positions), and listening task (forced choice identification versus oddball discrimination) were examined, with a view to assessing the relative importance of language-specific and language-independent factors operating at the acoustic-phonetic and phonological levels of signal processing in "foreign sound" speech perception. Both prior phonological learning and the relative acoustic discriminability of the items affected subjects' performance on the identification test. Where both factors were engaged, phonological learning effects predominated over the effects of acoustic discriminability. The extent to which a speaker encoded critical acoustic cues for the /r-l/ distinction was found to affect /r-l/ identification. Dynamic spectral features known to be relevant for the /r-l/ contrast were effective in predicting (in a linear regression analysis) speaker-dependent differences in identification scores. Although the discrimination test may have been influenced by ceiling effects, the performance profiles on the identification and discrimination tests were quite different, indicating that the identification and discrimination tests imposed quite different task demands upon listeners and that phonological processing of the signal was more engaged by the former task.     

Perception of /r/ and /l/ in a stop cluster: Evidence of cross-modal context effects.

Experiments were conducted investigating unimodal and cross-modal phonetic context effects on /r/ and /l/ identifications to test a hypothesis that context effects arise in early auditory speech processing. Experiment 1 demonstrated an influence of a preceding bilabial stop consonant on the acoustic realization of /r/ and /l/ produced within the stop clusters /ibri/ and /ibli/. In Experiment 2, members of an acoustic /iri/ to /ili/ continuum were paired with an acoustic /ibi/. These dichotic tokens were associated with an increase in "l" identification relative to the /iri/ to /ili/ continuum. In Experiment 3, the /iri/ to /ili/ tokens were dubbed onto a video of a talker saying /ibi/. This condition was associated with a reliable perceptual shift relative to an auditory-only condition in which the /iri/ to /ili/ tokens were presented by themselves, ruling out an account of these context effects as arising during early auditory processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

LiNi1/3Co1/3Mn1/3O2正极材料的合成与性能

采用共沉淀-高温固相法制备LiNi_1/3Mn_1/3Co_1/3O₂正极材料,利用XRD和SEM对所制试样的晶体结构和形貌进行表征,研究了烧结温度对材料电化学性能的影响.结果表明,焙烧温度为850 ℃制备的材料具有较好电化学性能,在25 ℃,电压范围为2.75~4.2 V,1 C充电6 C放电下首次放电比容量为124.2 mAh/g,50次循环后容量保持率为95.2 %.      

TbCu7型SmCo7-xHfx合金的结构及磁性能

采用熔体快淬法在40 m/s制备了SmCo_7-xHf_x （x=0, 0.1, 0.15, 0.2, 0.3）合金薄带,研究Hf取代量对SmCo_7-xHf_x合金的相组成、组织结构及磁性能的影响.结果表明:随Hf取代量的增加,均可获得TbCu₇型结构的亚稳相,晶格常数a和c也随之增加,c/a比值在0.82~0.83,晶粒平均尺寸减小,且更加均匀;在性能方面,Hf取代量为0.2时,可获得最优磁性能B_r为0.55 T和H_c为1 084 kA/m. Hf的添加还可有效改善合金高温性能,在27~400 ℃温度区间,矫顽力温度系数由未添加时-0.21 %/℃改善到-0.18 %/℃,提升14.3%.      

Antigenic drift between the haemagglutinin of the Hong Kong influenza strains A/Aichi/2/68 and A/Victoria/3/75

A DNA copy of the gene coding for the influenza A/Aichi/2/68 haemagglutinin protein was cloned in the plasmid pBR322 and the complete nucleotide sequence determined. Comparison of this primary structure and the deduced amino acid sequence with the haemagglutinin gene and protein of strains belonging to the same (H3) subtype and to different subtypes, of both human (H2) and avian (Hav1) origin, documents further at the molecular level the two independent modes of antigenic variation of the virus--drift and shift.     

Empirical Comparison of Design/Build and Design/Bid/Build Project Delivery Methods

This study compares the performance of design/bid/build and design/build to see if one project delivery method is superior in regards to time and cost. Similar military buildings were used to identify two samples of projects delivered with each of the two delivery methods. These projects provide a meaningful comparison because they include buildings of the same typology (i.e., U.S. Navy Bachelor Enlisted Quarters) delivered using similar design models. Project duration, project duration per bed, project time growth, cost growth and cost per bed were statistically compared. Upon completion of the analysis, the hypothesis that design/build projects are superior to design/bid/build projects in regards to time and cost was tested. Design/build projects were proven superior in performance in almost every measure. Other findings, including recommendations to practitioners and researchers, will be provided as well.     

La1-xCaxMnO3纳米单晶丝的制备及磁热效应研究

采用化学共沉淀法和热处理的方法制备了La1-xCaxMnO3(x=0.3,0.4,0.5)系钙钛矿型氧化物(LCMO),经XRD确定样品为钙钛矿型结构.TEM分析表明样品直径约为40nm的枝节状纳米丝,用△Tad-T测量仪测量了△Tad-T.与块状样品相比居里温度的波峰变宽,绝热磁温变降低.