Thermal Conductiviy of type I and II Clathrate Compounds

2000 ◽  
Vol 626 ◽  
Author(s):  
G.S. Nolas ◽  
J.L. Cohn ◽  
M. Kaeser ◽  
T.M. Tritt
Keyword(s):  
Thermal Conductivity ◽  
Type I ◽  
Lattice Structures ◽  
Type Ii ◽  
Clathrate Compounds ◽  
Materials Research ◽  
Small Band ◽  
Semiconducting Compounds ◽  
First Time ◽  
Type Crystal

ABSTRACTCompounds with clathrate-hydrate type crystal lattice structures are currently of interest in thermoelectric materials research. This is due to the fact that semiconducting compounds can be synthesized with varying doping levels while possessing low, even ‘glass-like’, thermal conductivity. Up to now most of the work has focused on type I Si and Ge clathrates. Sn-clathrates however are viewed as having the greatest potential for thermoelectric cooling applications due to the larger mass of Sn and the expected small band-gap, as compared to Si and Ge clathrates. Transport properties on type I Sn-clathrates has only recently been reported [1–3]. In this report we present ongoing experimental research on both type I and II clathrates with an emphasis on the thermal transport of these novel materials. We present thermal conductivity data Si-Ge and Ge-Sn alloys as well as on a type II Ge clathrate for the first time, and compare these data to that of other clathrate compounds.

Transport Properties of Type II Sodium-Silicon Clathrates

2005 ◽  
Vol 886 ◽  
Author(s):  
Matt Beekman ◽  
Jan Grkyo ◽  
George S. Nolas
Keyword(s):  
Thermal Conductivity ◽  
Sodium Content ◽  
Type I ◽  
Type Ii ◽  
Conductivity Measurements ◽  
Scanning Calorimetry ◽  
Resistivity Measurements ◽  
Silicon Clathrates ◽  
Covalently Bonded ◽  
First Time

ABSTRACTWe have synthesized the type II silicon clathrates Na1Si136 and Na8Si136, and report on the electrical and thermal transport in these materials. The crystal structure consists of a covalently bonded silicon framework in which sodium guest atoms are encapsulated inside the silicon host framework. Differential scanning calorimetry measurements show the compounds decompose above 600°C to diamond-structure silicon. Temperature dependant electrical resistivity measurements show the specimens to have an insulating character, with magnitudes that decrease with increasing sodium content. For the first time, thermal conductivity measurements on type II sodium-silicon clathrates are presented. The thermal conductivity is very low for both specimens, and for Na8Si136 exhibits a clear dip in the range from 50 to 70 K. These data suggest that the “rattling” behavior observed in type I clathrates may also be present in type II clathrates.

The theory of the crystallography of deformation twinning

1965 ◽  
Vol 288 (1413) ◽  
pp. 240-255 ◽  
Keyword(s):  
Crystal Structures ◽  
Deformation Twinning ◽  
Type I ◽  
Lattice Structures ◽  
Type Ii ◽  
Orientation Relationships ◽  
Tensor Calculus ◽  
Moving Interface ◽  
Twinning Shear ◽  
Crystallographic Characteristics

The crystallographic characteristics of deformation twinning are derived by considering the atomic movements which occur at the moving interface as a twin propagates. This is facilitated by making use of the notation of the tensor calculus, and general expressions, valid for all crystal structures, are obtained giving the magnitude of the twinning shear and relating the twinning elements for both type I and type II twinning. The atomic shuffles, which in general must accompany the twinning shear in both single and multiple lattice structures, are examined in detail and expressions are derived for their magnitudes and directions for the cases of the four classical orientation relationships associated with deformation twinning. The use of these expressions in predicting operative twinning modes is described and the relations between this theory and other recent theories of the crystallography of deformation twinning are discussed.

scholarly journals CLEAR AS MUD: THE TYPE I/TYPE II MODEL FOR DEATH RECEPTOR-INDUCED APOPTOSIS

2006 ◽  
Vol 43 (2) ◽  
Author(s):  
David Michael Conrad
Keyword(s):  
Death Receptor ◽  
Mitochondrial Pathway ◽  
Type I ◽  
Biological Processes ◽  
Type Ii ◽  
Type Ii Cell ◽  
Mort Cellulaire ◽  
Induced Apoptosis ◽  
First Time ◽  
The Relationship

Apoptosis is a highly organized form of cell death that plays an important regulatory role in many biological processes. The relationship between the two classical signalling pathways of apoptosis, the “death receptor” and “mitochondrial” pathways, was only vaguely appreciated until 1998, when death receptor pathway-mediated activation of the mitochondrial pathway was clearly demonstrated for the first time. The “type I/type II” model of death receptor-mediated apoptosis was proposed and subsequently adopted for use in categorizing cells according to the involvement of the mitochondrion duringdeath receptor-induced apoptosis. Since that time, however, different interpretations of the type I/type II cell definition have appeared in the literature and, consequently, the meaning of type I and type II cells has become less clear.L’apoptose est une forme de mort cellulaire très structurée qui joue un rôle important de régulation dans un grand nombre de processus biologiques. La relation entre les deux voies de signalisation traditionnelles de l’apoptose, la voie des « récepteurs de mort » et la voie mitochondriale, n’était connue que vaguement avant 1998, l'année où l’activation de la voie mitochondriale par l’intermédiaire de la voie des récepteurs de mort a été clairement démontrée pour la première fois. Le modèle « type I / type II » d’apoptose par l’intermédiaire des récepteurs de mort a été proposé puis adopté auxfins de catégorisation des cellules en fonction de la participation des mitochondries à cette apoptose. Depuis, différentes interprétations ont toutefois été formulées dans des ouvrages scientifiques quant à la définition des cellules de type I et de type II et, par conséquent, la signification de « cellules de type I » et de « cellules de type II » est devenue moins évidente.

Electron Staining Characteristics of the Inclusion Bodies of Type II Alveolar Epithelial Cells

1968 ◽  
Vol 26 ◽  
pp. 46-47
Author(s):  
Yutaka Kikkawa ◽  
Ho-Soon Hahn
Keyword(s):  
Epithelial Cells ◽  
Inclusion Bodies ◽  
Alveolar Epithelial Cells ◽  
Type I ◽  
Type Ii ◽  
Colloidal Iron ◽  
Alveolar Epithelial ◽  
Mammalian Lung ◽  
First Time ◽  
Electron Lucent

The inclusion bodies of Type II epithelial cells of the mammalian lung are oval and limited by a unit membrane. They contain highly osmiophilic material. With the standard method of fixation this material is irregularly separated by a number of electron-lucent spaces (Figure 1). Because of this appearance, the inclusion bodies are often referred to as “lamellar inclusions”. Measurable periodic lamellae, however, have never been observed in the inclusions which are located intracellularly.During the course of the studies to localize acid mucopolysaccharides in the distal air way of the rabbit and rat, it is found that the alveolar surface of the cell membranes of both Type I and II cells and the inclusion bodies within Type II cells satin heavily with colloidal iron at pH 2.0 following the osmication of the tissue with phosphate-buffered solution at pH 7.4 (Figure 2). In addition, the inclusion bodies for the first time show regular periodic lamellae. Each line is granular and measures about 60 Å in width (Figure 3).

Effect of Envelope Films on Thermal Properties of Vacuum Insulation Panels with Glass Fiber

2011 ◽  
Vol 415-417 ◽  
pp. 859-864 ◽  
Author(s):  
Wang Ping Wu ◽  
Zhao Feng Chen ◽  
Jie Ming Zhou ◽  
Xue Yu Cheng
Keyword(s):  
Thermal Conductivity ◽  
Glass Fiber ◽  
Core Material ◽  
Type I ◽  
Type Ii ◽  
The Core ◽  
Vacuum Insulation ◽  
Porosity Ratio ◽  
Thermal Conductivities ◽  
Core Materials

The VIPs consist of the glass-fiber core material and two types of envelope film. The glass fiber was fabricated by a centrifugal blowing process. The core material was prepared by the wet method. The thermal conductivities of the materials were measured by the heat flow meter. The microstructure of the envelope film was observed by scanning electron microscopy. The porosity ratio and largest pore size diameters of the core materials are 92.27% and 20μm, respectively. The thermal conductivity of the VIP is about 8-10 times higher than that of the core materials. The thickness of type I and II envelope films are 45μm and 400μm, respectively. The thermal conductivities of the type I and type II envelope films are 0.11W/(m•K) and 0.69W/(m•K), respectively. The thermal conductivity of the VIP with type II envelope is higher than that of the VIP with type I envelope, which is attributed to the different structures and thickness of the envelope film.

scholarly journals Evolution of co-regulatory network of C4 metabolic genes and TFs in the genus Flaveria: go anear or away in the intermediate species?

2020 ◽  
Author(s):  
Ming-Ju Amy Lyu ◽  
Jemaa Essemine ◽  
Faming Chen ◽  
Genyun Chen ◽  
Xin-Guang Zhu
Keyword(s):  
Regulatory Network ◽  
Regulatory Networks ◽  
Evolutionary Process ◽  
Type I ◽  
Type Ii ◽  
Intermediate Species ◽  
Closely Related Species ◽  
Metabolic Genes ◽  
Species Specific ◽  
First Time

AbstractC4 photosynthesis evolved from the ancestral C3 photosynthesis by recruiting pre-existing genes to fulfill new functions. The enzymes and transporters required for the C4 photosynthesis have been intensively studied; however, the transcription factors (TFs) regulating these C4 metabolic genes are not well understood. In particular, how the TF regulatory network of C4 metabolic genes was rewired during the evolution is unclear. Here, we constructed TFs co-regulatory networks for core C4 metabolic genes (C4GRN) for four evolutionarily closely related species from the genus Flaveria, which represent four different evolutionary stages of the C4 photosynthesis, namely, C3, type I C3-C4, type II C3-C4 and C4. Our results show that more than half of the co-regulations of TFs and C4 core metabolic genes were species specific. The counterparts of C4 genes in C3 species were already co-regulated with the photosynthesis-related genes; whereas the required TFs for the C4 photosynthesis were recruited later. The type I C3-C4 species recruited 40% of C4 required TFs which co-regulated all core C4 metabolic genes but PEPC; nevertheless, the type II C3-C4 species took on a high divergent C4GRN with C4 species itself. In C4 species, PEPC and PPDK-RP possessed much more co-regulated TFs than other C4 metabolic genes. This study provides for the first time the TFs profiles of the C4 metabolic genes in species with different photosynthetic types and reveal the dynamic of C4 genes-TFs co-regulations along the evolutionary process, providing thereby new insights into the evolution of C4 photosynthesis.

Studien zum Vorgang der Wasserstoffübertragung, 72 [1] Versuche zur enantioselektiven Homogenhydrierung von N-Acyl-α-aminozimtsäuren mit Rh(I)-Komplexen unter Verwendung neuer optisch aktiver Co-Katalysatoren/Studies on the Occurrence of Hydrogen Transfer, 72, [1] Investigation on the Enantioselective Homogeneous Hydrogenation of N-Acyl-α-aminocinnamic Acids with Rh(I)-Complexes Using New Optically Active Co-Catalysts

1984 ◽  
Vol 39 (4) ◽  
pp. 512-516 ◽  
Author(s):  
L. Horner ◽  
G. Simons
Keyword(s):  
Hydrogen Transfer ◽  
Optically Active ◽  
Type I ◽  
Type Ii ◽  
Homogeneous Hydrogenation ◽  
Active Compounds ◽  
Co Catalyst ◽  
Co Catalysts ◽  
Optical Induction ◽  
First Time

3 Optically active compounds of the type I and 15 optically active compounds of the type II were investigated as co-catalysts in the homogeneous hydrogenation of N-acyl-α-aminocinnamic acids using standard conditions. In the co-catalysts of the type I the phosphorus atom is the center of the asymmetry. In the representatives of type II the side chain is optically active and the three bonded phosphorus either achiral or optically active.The results of the homogeneous hydrogenation are deposited in the Tables I-IV. In the Tables I and IV the degree of the optical induction and the configuration of the excess enantiomer are determined using Rh/P-ratios 1:1,1 and 1:2,2. The Tables II and III show the results applying a Rh/P-ratio of 1:2,2. The observed degree of optical induction is low with the co-catalysts 1-18; only the co-catalyst 19 shows an optical induction of 68%. A change of the configuration of the excess enantiomer of N-benzoylphenylalanine formed by the homogeneous hydrogenation of N-benzoyl-α-cinnamic acid for the first time was observed by varying the Rh/P-ratio of the co-catalysts 14, 17 and 18 from 1:1,1 to 1:2,2.

scholarly journals Transport Characteristics of Fujifilm Ion-Exchange Membranes as Compared to Homogeneous Membranes АМХ and СМХ and to Heterogeneous Membranes MK-40 and MA-41

Membranes ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 84 ◽  
Author(s):  
Sarapulova ◽  
Shkorkina ◽  
Mareev ◽  
Pismenskaya ◽  
Kononenko ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Volume Fraction ◽  
Transport Numbers ◽  
Type I ◽  
Type Ii ◽  
Ion Exchange Membranes ◽  
Electrospinning Method ◽  
Microheterogeneous Model ◽  
First Time

Ion-exchange membranes (IEMs) find more and more applications; the success of an application depends on the properties of the membranes selected for its realization. For the first time, the results of a comprehensive characterization of the transport properties of IEMs from three manufactures (Astom, Japan; Shchekinoazot, Russia; and Fujifilm, The Netherlands) are reported. Our own and literature data are presented and analyzed using the microheterogeneous model. Homogeneous Neosepta AMX and CMX (Astom), heterogeneous MA-41 and MK-40 (Shchekinoazot), and AEM Type-I, AEM Type-II, AEM Type-X, as well as CEM Type-I, CEM Type-II, and CEM Type-X produced by the electrospinning method (Fujifim) were studied. The concentration dependencies of the conductivity, diffusion permeability, as well as the real and apparent ion transport numbers in these membranes were measured. The counterion transport number characterizing the membrane permselectivity increases in the following order: CEM Type-I MA-41 < AEM Type-I < MK-40<CMX CEM Type-II CEM Type-X AEM Type-II < AMX < AEM Type-X. It is shown that the properties of the AEM Type-I and CEM Type-I membranes are close to those of the heterogeneous MA-41 and MK-40 membranes, while the properties of Fujifilm Type-II and Type-X membranes are close to those of the homogeneous AMX and CMX membranes. This difference is related to the fact that the Type-I membranes have a relatively high parameter f2, the volume fraction of the electroneutral solution filling the intergel spaces. This high value is apparently due to the open-ended pores, formed by the reinforcing fabric filaments of the Type-I membranes, which protrude above the surface of these membranes.

Temperature-dependent halogen⋯halogen synthon crossover in coordination compounds

CrystEngComm ◽  
2014 ◽  
Vol 16 (36) ◽  
pp. 8479-8485 ◽  
Author(s):  
Hamid Reza Khavasi ◽  
Maryam Esmaeili
Keyword(s):  
Coordination Compounds ◽  
Type I ◽  
Type Ii ◽  
Temperature Dependent ◽  
First Time

The crossover between type I and type II Br⋯Br synthons on the formation of coordination compounds has been investigated for the first time.

scholarly journals Diverse Controlling Mechanisms and Teleconnections of Three Distinctive MJO Types

2021 ◽  
Author(s):  
Shihua Liu ◽  
Joshua Xiouhua Fu ◽  
Zhiping Wen ◽  
Peng Zhang
Keyword(s):  
Large Scale ◽  
Western Indian Ocean ◽  
Boreal Winter ◽  
Type I ◽  
Type Ii ◽  
Global Mode ◽  
Type Iii ◽  
Dry Zone ◽  
Upper Level ◽  
First Time

Abstract In present study, three distinctive MJO types in boreal winter are documented and their controlling mechanisms and teleconnections are investigated with a synergetic glocal approach. For the first time, it is revealed that the diverse nature of the MJO primarily results from different Tropical-Extratropical Interactions and associated internal atmospheric processes. Both the type-I and type-II are initiated over the western Indian Ocean (IO) by a dry zone around the eastern IO, while only the type-I can move out the IO and circulate around the globe. The type-III initiates over the western Pacific (WP) and can circulate the globe and trigger another successive event. The strong upper-level equatorial westerly over the IO-WP, resulting from upstream and extratropical influences, suffocates the type-II MJO within the IO. On the other hand, the robust upper-level equatorial easterly over the IO-WP, also resulting from upstream and extratropical influences, along with regional convective instability over the WP and the arrival of east-Asian cold-surge foster the development and eastward propagation of the type-III MJO. The downstream and extratropical teleconnections are primarily controlled by the associated convection over the tropical IO-WP sector for the type-I, but also strongly influenced by the conditions over the extratropical WP for the type-II and type-III. Given that the MJO has been traditionally viewed as a tropical mode owing its existence to the coupling between organized convection and large-scale circulations, present findings advocate the MJO as a global mode and call for more research on the involved Tropical-Extratropical Interactions in order to better understand and simulate the diverse nature of the MJO.

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