155 research outputs found
Morphological manipulation of ultrafine CeO2 powder and silver supported type catalysts for soot combustion
碳烟颗粒(PM),是柴油机尾气排放的主要污染物,其中很大比例(>95%)是粒径小于2.5m的颗粒(PM2.5),容易悬浮在空气中,从而被人或动物呼吸进入体内,导致肺癌、哮喘等疾病,严重危害人体健康。目前在柴油机设计中,常采取机内净化和尾气处理两种减排策略,但随着排放标准不断紧缩,单纯依靠机内净化不仅无法达标,且会限制机动车的动力性与经济性,因而发展后处理技术势在必行。 颗粒物捕集器(DPF)是采用尺寸效应对尾气颗粒物进行滤除的装置,是目前柴油内燃机中最有效的颗粒物去除手段。为防止碳颗粒在过滤器上过度积累而堵塞过滤器,进而影响柴油机性能,须采用完全氧化的方式将其在线消除。然而,...Particulate matter (PM), especially a large portion of PM2.5 (the particle size is smaller than 2.5um) is the main pollutants from diesel engine. For it can easily suspend in the air and inhaled by people and be apt to cause lung cancer, asthma and other diseases which are harmful to human health. As a consequence, the regulations on emissions become more stringent. Nowadays, there are two strateg...学位:理学硕士院系专业:化学化工学院_化学学号:2052010115162
塞辅音和声调知觉问题
本文报告的两个实验以合成的汉语普通话CV音节作刺激,研究了塞辅音与声调之间在知觉上的相互作用问题。主要结果是:(1)塞辅音的发音方式影响声调的知觉,不送气音使听者在辨别声调时倾向于基频曲线起点高的声调反应; (2)音节的声调也影响对塞音发音方式的判断,在一、四声音节里,听者倾向于将塞辅音听成不送气音,在二、三声音节里,听成送气音。</p
Preparation of Morphology-Tuned γ-MnO_2 and Catalytic Performance for the Liquid-Phase Oxidation of Toluene
通过在回流法制备流程中引入CTAb(十六烷基三甲基溴化铵)、PEg6000(聚乙二醇6000)及P123(聚环氧乙烷-聚环氧丙烷-聚环氧乙烷三嵌段共聚物)等表面活性剂对γ-MnO2催化剂进行形貌控制,同时采用X射线衍射(Xrd)、扫描电镜(SEM)、n2吸附(bET)、热重分析(TgA)、O2程序升温脱附(O2-TPd)以及H2程序升温还原(H2-TPr)等技术对不同形貌γ-MnO2的结构、氧脱附及还原性能进行表征,并考察了其在常压和无溶剂条件下甲苯选择性氧化反应体系的催化特性.同时,对于陈化时间对形貌的影响作用进行了考察.结果表明:不同形貌的γ-MnO2的氧化还原特征及催化活性存在显著差异,其中在经PEg6000进行修饰的γ-MnO2中含有较多的阴离子空位及混合价态,因此有助于分子氧在表面的活化,具有较高的表面比活性;而经P123进行表面修饰的γ-MnO2成晶结构规整、比表面积大,对甲苯液相直接氧化反应则表现出最佳的质量比活性,甲苯转化率达18.1%,含氧化合物总选择性为87.4%,其中苯甲酸的选择性达到73.2%.Introducing surfactants including hexadecyltrimethylammonium bromide (CTAB),macrogol 6000 (PEG6000),and poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) triblock copolymer (P123) into the refluxing aqueous crystal nucleus slurry yielded morphology-tuned microcrystalline γ-MnO2.γ-MnO2 and the influence of surfactant modification were investigated by X-ray diffraction (XRD),scanning electron microscopy (SEM),N2 adsorption (BET),thermogravimetry analysis (TGA),O 2 temperature programmed desorption (O2-TPD),and temperature programmed H2 reduction (H 2-TPR).Surfactants led to differences in γ-MnO2 morphology,surface area,oxygen desorption behavior and reducibility.The effect of reflux time on catalyst morphology is discussed.The catalytic performance of γ-MnO2 during the solvent-free atmospheric oxidation of toluene was evaluated.PEG6000 modified γ-MnO2 exhibited the highest catalytic activity judging by surface area because of a greater mixed valency and more anion vacancies.The greatest mass specific activity was obtained for P123 modified γ-MnO2 with the largest surface area.Optimized reaction conditions yielded an 18.1% toluene conversion,and 87.4 and 73.2% total selectivity and selectivity for benzoic acid,respectively.国家重点基础研究发展规划项目(973)(2010CB226903)资助~
聚酰胺硅胶吸附茶多酚的红外光谱研究
IR谱表明:聚酰胺硅胶吸附剂中,聚酰胺的N—H和硅胶表面OH以氢键结合,υC=O无位移;室温下该吸附剂中C=O和茶多酚中O—H作用后,υC=O和υO—H分别红移了11cm-1和18cm-1;而与咖啡因及氨基酸作用后υC=O无位移
ANALYSES ON LDH ISOENZYME AND PROTEIN FROM BOTH GUANGDONG STRAIN AND FUJIAN STRAIN OF ECHINOCHASMUS FUJIANENSIS
目的 探讨福建与广东两地福建棘隙吸虫生化特点。方法 用不连续聚丙烯酰胺凝胶电泳及薄层等电聚焦电泳等进行比较分析虫体乳酸脱氢酶 (LDH)同工酶和蛋白质。结果 福建与广东两地虫株都有 5种LDH同工酶 ,其中LDH1、LDH4 和LDH5的迁移率相同 ;蛋白质电泳都分离出 9条区带 ,其中有 7条带的等电点相同。但在LDH2 和LDH3 的迁移率 ,蛋白质区带的相对含量 ,同工酶的总活力与比活力 ,以及A和B亚基的含量等存在差异。结论 LDH同工酶与蛋白质的某些差异 ,可归因为基因型相似条件下所出现两地虫株生化遗传上差异Aim\ Inguired into the biochemical characteristrics of Echinochasmus fujianensis found in Fujian and Guangdong provinces. Methods\ Compared and analysed two strains by LDH isoenzyme eletrophoresis, discontinuous PAGE and thinlayer isoelectric equilibrium PAGE.Results\ Two strains both had five LDH isoenzyme, among them, LDH\-1、LDH\-4 and LDH\-5 had the same mobilities. There were nine bands in protein electrophoresis. Seven bands had the same isoelectric point.But there were differences in the mobilities of LDH\-2 and LDH\-3,the comparative amount of protein bands, total and specific activity of isoenzyme and the amount of A and B subunit. Conclusion Under the similar condition of genotypes, the differences of the biochemical inheritance can be contributed to the differences of LDH isoenzyme and protein.福建省科技计划基金资助项目!(No.98-Z-156);; 福建省“百千万人才”人选培养资金资助项
SURVEY OF MIXED INFECTIONS OF FISH-BORNE TREMATODES IN PINYUAN COUNTY AND DNA(RAPD)ANALYSIS
目的 调查广东省平远县棘隙吸虫及其他鱼源性吸虫混合感染情况。方法 对鱼类宿主取鱼鳃和鱼肉等组织 ,镜检囊蚴 ;用水洗过筛沉淀法粪检虫卵 ,部分虫卵阳性动物解剖检查。采用DNA -RAPD技术 ,比较福建棘隙吸虫广东株与福建株。结果 查出华支睾吸虫 (Clonorchissinensis)、东方次睾吸虫 (Metorchisorientalis)、福建棘隙吸虫 (Echinochasmusfujianensis)、日本棘隙吸虫 (E japonicus)、抱茎棘隙吸虫 (E perfoliatus)和钩棘单睾吸虫 (Haplorchispumilio) 6种。第二中间宿主为麦穗鱼等 11种 ,感染率 48 3% (182 / 377) ,有 92 4%的阳性鱼混合感染 2种以上吸虫囊蚴。保虫宿主狗、猫感染率 79 2 % (19/ 2 4) ,每只阳性动物均有 2种以上吸虫混合感染。 15个引物在福建棘隙吸虫广东株与福建株两者共获DNA片段 185个 ,共享度 (F) =0 984,遗传距离 (D) =0 0 16。结论 当地为人兽共患的多种鱼源性吸虫混合感染区。形态学观察和分子生物学检测结果相印证 ,福建棘隙吸虫广东株与福建棘隙吸虫福建株为同一虫种。Aim To seek the possible existence of mixed infections of Echinochasmus fujianensis and other fish-borne tremtodes in Pinyuan county,Guangdong.Methods Metacercariae of trematodes were detected from gills,muscles and some other tissues of freshwater fish and examintd under microscopy Sedimentation pocedures were used to observe parasite ova in stool Adult worms were obtained from definitive animal hosts upon dissection Experimental animal infection were performed from metacercariae of E fujianensis strains in Fujian and Guangdong,and it's DNA analysis Random amplified Polymorphic DNA(RAPD).Results Six species of trematodes were found,including Clonorchis sinensis,Metorchis orientalis,E fujanensis, E japonicus,E perfoliatus and Haplorchis pumilio Eleven species of freshwater fish comprising Pseudorasbora parve were identified as the second intermediate hosts,with an average positive rate of 48 33%(182/377) The overall mixed infection animal were contracted with 2 or more species Dogs and cats were detected to be reservoir hosts,the total infection rate being 79 2%(19/24).92 4% of infecded fish were contracted with 2 or 6 speies of the metacercariae of trematodes 185 DNA fragments were obtained by 15 primers,F=0 894 and D=0 016 between E fujianensis Guandong and Fujian strain Conclusion There are six species of fish-borne trematodes which may cause infections in human and animal in the regions E fujianensis Guangdong stain and Fujian strain are the same species福建省科技计划基金!资助项目 (No 98-Z - 1 56);; 福建省“百千万人才”人选培养资
塞辅音和声调知觉问题
本文报告的两个实验以合成的汉语普通话CV音节作刺激,研究了塞辅音与声调之间在知觉上的相互作用问题。主要结果是:(1)塞辅音的发音方式影响声调的知觉,不送气音使听者在辨别声调时倾向于基频曲线起点高的声调反应; (2)音节的声调也影响对塞音发音方式的判断,在一、四声音节里,听者倾向于将塞辅音听成不送气音,在二、三声音节里,听成送气音。</p
人的听觉调谐曲线
听觉系统的频率选择性可以用调谐曲线及其Q值表征。本研究用同时掩蔽法测定了10名正常听者和5名听力衰退者的心理物理调谐曲线和生理调谐曲线。为便于两种曲线的比较,实验用了相同的声刺激,即频率为50DHz和4000Hz的感觉级相同的短音。测定生理调谐曲线所用的电生理指标为脑干反应的P_6—SN_(10)复合波的幅值。实验结果表明:(1)两种调谐曲线的锐度Q没有显著的差异,(2)听力衰退者4000Hz的两种调谐曲线的锐度Q都显著地小于正常听力者相应曲线的锐度Q。本文说明用适当的声刺激和电生理指标,生理调谐曲线能够和心理物理调谐曲线近似等值地、同样灵敏地、具有频率特殊性地反映听系统的频率选择性及其变化
话题结构对语篇情绪更新的影响
读者在阅读理解的过程中, 能够推断出故事主角的情绪状态, 并能随着语篇中的情绪变化做出情绪更新。在加工情绪信息的同时, 读者也加工语篇结构方面的信息, 二者皆有可能随着语篇的展开而发生变化。本研究采用自定步速阅读的方法, 分别在外显和内隐两种情绪加工任务下, 考察话题结构对语篇情绪更新的影响。结果发现, 在实验 1 的外显情绪判断任务下, 话题结构未显示出对语篇情绪更新的作用; 在实验2 和实验 3 的内隐情绪理解任务下, 话题延续时, 情绪转换句的阅读时间长于情绪延续句, 此时情绪更新需要额外的加工时间; 而话题转换时, 二者没有显著差异, 说明此时读者在新结构下建立当前句的情绪表征,并不受到先前情绪的影响
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