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Search Results: 1 - 10 of 298481 matches for " Brécey "
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Ce改性对Y型分子筛酸性及其催化转化性能的调变机制
Modulation of the Acidity and Catalytic Conversion Properties of Y Zeolites Modified by Cerium Cations

张畅,秦玉才,高雄厚,张海涛,莫周胜,初春雨,张晓彤,宋丽娟
- , 2015, DOI: 10.3866/PKU.WHXB201412163
Abstract: 采用液相离子交换(LPIE)法制备了不同离子交换度的CeY分子筛. 运用电感耦合等离子发射光谱(ICPAES)、X射线衍射(XRD)、N2吸附等温线和氨气程序升温脱附(NH3-TPD)等方法对其进行表征, 采用原位傅里叶变换红外(in situ FTIR)光谱技术分别以吡啶和噻吩作为探针分子研究了Ce改性对Y型分子筛酸性能和催化转化性能的影响规律. 结果表明, Ce离子改性不改变Y 型分子筛晶体的基本骨架, 但改变其精细结构. 分子筛改性过程中Ce物种优先定位于方钠石(SOD)笼, 随着稀土离子含量增大, 逐渐出现在超笼中. Ce离子交换过程中产生一定量的Br?nsted (B)酸中心, 且其量与强度随着Ce含量的增大均呈现先增加后平稳的趋势. 同时, Ce离子交换产生与非骨架铝物种和铈物种有关的两种强度不同的Lewis (L)酸中心, 且两者均随着Ce含量的增大而增大. 噻吩吸附红外光谱表明, 由于Ce离子改性产生的强B酸中心可导致噻吩在室温条件下即可发生质子化反应, 质子化的噻吩分子可进一步发生低聚反应. 而稀土物种与B酸中心的协同作用有利于低聚反应的发生.
Y-type zeolites with different cerium ion content were prepared by liquid phase ion exchange (LPIE) and their structural properties were characterized by inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray diffraction (XRD), N2 adsorption isotherm, and temperature-programmed desorption of ammonia (NH3-TPD). The influence of cerium ion modification of the Y-type zeolites on the acidity and catalytic behavior was studied by in situ Fourier transform infrared spectroscopy (in situ FTIR) techniques with pyridine and thiophene as probe molecules. The results indicate that the original crystal structures of the zeolites remain unchanged after modification with cerium ions. During the modification process the Ce species tend to be located in sodalite (SOD) cages after calcination and remain in the supercages upon a gradual increase in Ce cation content. The amount and strength of the Br?nsted (B) acid sites in the zeolites generated by the modification increases initially and then stabilizes with an increase in Ce ion content. The strong and weak Lewis (L) acid sites related to the non-framework aluminum and the rare earth species increase continuously during the modification process. Thiophene adsorption FTIR spectra indicate that the adsorbed thiophene molecules protonate at the strong Br?nsted acid sites of the zeolites. The protonated products then oligomerize. The synergy between Ce species and B acid sites is favorable for the thiophene oligomerization reaction
Les batiments ruraux dans leur environnement en pays de bocage et en pays d’openfield
Pierre Brunet
In Situ : Revue de Patrimoines , 2012, DOI: 10.4000/insitu.2545
Abstract: En pays de bocage comme en pays d’openfield, l’étude de l’inscription des batiments dans le paysage, de leur répartition sur le parcellaire, est essentielle à une bonne compréhension de l’architecture rurale. Plus que toute autre, l’évolution du dernier demi-siècle a entra né la disparition ou la transformation de nombreuses constructions et aménagements, modifiant en profondeur la relation de l’architecture avec l’environnement. Both in bocage country and in open-field country, the study of the ways buildings are set in the landscape and the ways they are disposed on the plot of property is essential for the correct understanding of rural architecture. More than in earlier periods, the last fifty years have seen the disappearance or the transformation of many buildings and structures, profoundly changing the relation between architecture and the environment.
铈离子改性y型分子筛吸附剂对苯中噻吩动态吸附及其主要影响因素的研究
常晋豫,廖俊杰,张艳军,范利君,马琳,鲍卫仁,常丽萍
燃料化学学报 , 2013,
Abstract: ?通过固定床吸附实验考察了吸附剂的粒径、空速与浓度及床层温度等操作参数对苯中噻吩吸附的影响。结果表明,上述因素分别通过改变内、外扩散过程的传质阻力以及其物理吸附行为来影响噻吩的脱除。最佳的参数是,吸附剂粒径为0.2~0.3mm,空速为0.85h-1,床层温度为室温。在此条件下,cey吸附剂能将噻吩浓度为500mg/l苯溶液中的噻吩完全脱除,其噻吩的穿透时间和吸附量可达400min和4.61mg/g以上。
ce改性对y型分子筛酸性及其催化转化性能的调变机制
张畅,秦玉才,高雄厚,张海涛,莫周胜,初春雨,张晓彤,宋丽娟
物理化学学报 , 2015,
Abstract: 采用液相离子交换(lpie)法制备了不同离子交换度的cey分子筛.运用电感耦合等离子发射光谱(icpaes)、x射线衍射(xrd)、n2吸附等温线和氨气程序升温脱附(nh3-tpd)等方法对其进行表征,采用原位傅里叶变换红外(insituftir)光谱技术分别以吡啶和噻吩作为探针分子研究了ce改性对y型分子筛酸性能和催化转化性能的影响规律.结果表明,ce离子改性不改变y型分子筛晶体的基本骨架,但改变其精细结构.分子筛改性过程中ce物种优先定位于方钠石(sod)笼,随着稀土离子含量增大,逐渐出现在超笼中.ce离子交换过程中产生一定量的br?nsted(b)酸中心,且其量与强度随着ce含量的增大均呈现先增加后平稳的趋势.同时,ce离子交换产生与非骨架铝物种和铈物种有关的两种强度不同的lewis(l)酸中心,且两者均随着ce含量的增大而增大.噻吩吸附红外光谱表明,由于ce离子改性产生的强b酸中心可导致噻吩在室温条件下即可发生质子化反应,质子化的噻吩分子可进一步发生低聚反应.而稀土物种与b酸中心的协同作用有利于低聚反应的发生.
山东中新世山旺组葛属(豆科)小叶的形态及其古生态学意义
Leaflet Morphology of Pueraria (Leguminosae) from the Miocene Shanwang Formation of Shandong Province and Its Palaeoecological Implications
 [PDF]

王祺, 徐洪河, 申思
Botanical Research (BR) , 2012, DOI: 10.12677/BR.2012.12003
Abstract: 葛属Pueraria是豆科蝶形花亚科、菜豆族大豆亚族中最大的、具有三小叶复叶的属,其大多数种为攀援性藤本植物,分布于东亚、南亚、东南亚和大洋洲。化石记录表明,葛属早在中新世就已出现在东亚、巴尔干半岛和高加索地区的亚热带和温带植物群中,目前已知有3个化石种,即中国山旺中新世的荚果化石山旺葛藤P. shanwangensis、山旺和日本数个中、上新世产地的叶、小叶化石鲁葛藤P. miothunbergiana以及克罗地亚和格鲁吉亚阿布哈兹中新世的小叶化石大葛藤P. maxima。本文基于对中新世山旺组最近采集的葛属小叶印痕化石的观察和对现生种葛P. montana小叶的形态比较,研究了该属化石种的小叶形态和发育变异。结果表明,现生种葛与化石种鲁葛藤和大葛藤的小叶都具有不甚发育的间二级脉,这个特征在先前报道的鲁葛藤小叶化石中未见保存。另外,它们的主脉和二级脉远轴侧有时都会分别发出两条挨得很近、角度不同的二级脉和二级脉梳脉,这个特征过去在葛属中则被忽视了。总体上,葛属小叶化石的叶脉特征在中新世广阔的欧亚中纬度地区显示了高度的相似性。目前,仅在中国中新世山旺植物群和日本中新世高峰山组植物群中发现了与现生的葛小叶相似的、具有裂瓣的鲁葛藤小叶化石,但现生葛比化石葛的小叶更大些、似乎发育了更多具有裂瓣的小叶,这可能与中新世以来大气二氧化碳浓度的变化有关。现生葛长在荫蔽生境以及攀援于支持物(如藤架或其他木本植物)上的植株比生于开阔生境以及蔓生的植株发育了更多的、具有裂瓣的小叶,这可能有效促进了整株植物的叶片和冠层中的光照截取和通风散热。据此推测,中国和日本中、上新世的鲁葛藤居群可能比克罗地亚和阿布哈兹中新世的大葛藤居群的生态耐受性更加宽泛,东亚的居群既生于荫蔽的、更多依赖森林的生境中,也长在开阔的、较少依赖森林生境中,甚至蔓生。
Pueraria DC. is the largest papilionoid legume, trifoliolate genus of the subtribe Glycininae in the tribe Phaseoleae, the majority species of which are climbing lianas distributed in East Asia, South Asia, Southeast Asia, and Oceania. The known three fossil species of Pueraria described from the subtropical and temperate floras of the Balkan Peninsula, the Caucasus, and eastern Asia respectively are P. shanwangensis (fruit) from the Miocene Shanwang of China, P. miothunbergiana (leaf and leaflet) from the Miocene of Shanwang and numerous localities in the Mio-Pliocene of Japan, and P. maxima (leaflet) from the Miocene of Croatia and Georgian Abkhazia. On the basis of observations on the newly collected Pueraria leaflet impres-sions and comparisons with the leaflets of living P. montana, the morphology and developmental variation of Pueraria leaflet fossils are studied. The result shows that the leaflets of both living species P. montana and fossil species P. miothunbergiana and P. maxima bear poorly developed intersecondary veins, which were not observed in former reports on P. miothunbergiana. Also, two adjacent secondary veins or agrophic veins at different angles are sometimes diverged respectively from the primary vein (midvein) and the exmedial side of secondary veins in both extant and fossil Pueraria leaflets, which is a feature that has long been neglected. Overall, the venation of fossil Pueraria leaflets that are widely occurred across the Miocene of middle lati-tudes in Eurasia is highly similar, but the lobed leaflets similar to those of living P. montana are only discov-ered from the Miocene Shanwang flora of China and Takamine flora of Japan. Extant P. montana bears larger leaflets than fossil Pueraria and seems to have developed more lobed leaflets than fossil P.
弘扬义理 重建道统——《国学》发刊词
 [PDF]

陈杰思
Chinese Traditional Culture (CnC) , 2013, DOI: 10.12677/CNC.2013.11001
Abstract:  
《战后日本政治与外交》书评  [PDF]
孟凡礼
Open Journal of Historical Studies (OJHS) , 2014, DOI: 10.12677/OJHS.2014.22004
Abstract:
《英语前置修饰语的结构及意义》述评
 [PDF]

刘承宇
Modern Linguistics (ML) , 2014, DOI: 10.12677/ML.2014.22009
Abstract:
创刊词
 [PDF]

郑新奇
Urbanization and Land Use (ULU) , 2013, DOI: 10.12677/ULU.2013.11001
Abstract:


Book Review: Pacon Ke: Photosynthesis-Photons, Excitons, Electrons, Protons, Ions and Their Interactions With Photosynthetic Membrane
评葛培根编著:《光合作用——光手、激子、电子、质子、离手与光合膜之间的相互作用》

Tang Pei-song,Dai Yun-ling,Kuang Ting-yun,
汤佩松
,戴云玲,匡廷云

植物学报 , 1992,
Abstract:
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