scholarly journals Homo-composition and hetero-structure nanocomposite Pnma Bi2SeS2 - Pnnm Bi2SeS2 with high thermoelectric performance

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Bushra Jabar ◽  
Fu Li ◽  
Zhuanghao Zheng ◽  
Adil Mansoor ◽  
Yongbin Zhu ◽  
...  
Keyword(s):  
Phase Transition ◽  
Figure Of Merit ◽  
Structural Difference ◽  
Ex Situ ◽  
Second Phase ◽  
General Strategy ◽  
Hetero Structure ◽  
High Figure ◽  
Two Phases

AbstractNanocomposite engineering decouples the transport of phonons and electrons. This usually involves the in-situ formation or ex-situ addition of nanoparticles to a material matrix with hetero-composition and hetero-structure (heC-heS) interfaces or hetero-composition and homo-structure (heC-hoS) interfaces. Herein, a quasi homo-composition and hetero-structure (hoC-heS) nanocomposite consisting of Pnma Bi2SeS2 - Pnnm Bi2SeS2 is obtained through a Br dopant-induced phase transition, providing a coherent interface between the Pnma matrix and Pnnm second phase due to the slight structural difference between the two phases. This hoC-heS nanocomposite demonstrates a significant reduction in lattice thermal conductivity (~0.40 W m−1 K−1) and an enhanced power factor (7.39 μW cm−1 K−2). Consequently, a record high figure-of-merit ZTmax = 1.12 (at 773 K) and a high average figure-of-merit ZTave = 0.72 (in the range of 323–773 K) are achieved. This work provides a general strategy for synergistically tuning electrical and thermal transport properties by designing hoC-heS nanocomposites through a dopant-induced phase transition.

Effect of mass transport along interfaces and grain boundaries on copper interconnect degradation

2004 ◽  
Vol 812 ◽  
Author(s):  
Ehrenfried Zschech ◽  
Moritz A. Meyer ◽  
Eckhard Langer
Keyword(s):  
Mass Transport ◽  
Grain Boundaries ◽  
Void Formation ◽  
Degradation Process ◽  
Copper Interconnects ◽  
Second Phase ◽  
Copper Interconnect ◽  
Void Evolution ◽  
Two Phases

AbstractIn-situ SEM electromigration studies were performed at fully embedded via/line interconnect structures to visualize the time-dependent void evolution in inlaid copper interconnects. Void formation, growth and movement, and consequently interconnect degradation, depend on both interface bonding and copper microstructure. Two phases are distinguished for the electromigration-induced interconnect degradation process: In the first phase, agglomerations of vacancies and voids are formed at interfaces and grain boundaries, and voids move along weak interfaces. In the second phase of the degradation process, they merge into a larger void which subsequently grows into the via and eventually causes the interconnect failure. Void movement along the copper line and void growth in the via are discontinuous processes, whereas their step-like behavior is caused by the copper microstructure. Directed mass transport along inner surfaces depends strongly on the crystallographic orientation of the copper grains. Electromigration lifetime can be drastically increased by changing the copper/capping layer interface. Both an additional CoWP coating and a local copper alloying with aluminum increase the bonding strength of the top interface of the copper interconnect line, and consequently, electromigration-induced mass transport and degradation processes are reduced significantly.

Vibrational and Electronic Properties of RbC60 Thin Films

1994 ◽  
Vol 359 ◽  
Author(s):  
G.P. Lopinski ◽  
M.G. Mitch ◽  
J.R. Fox ◽  
J.S. Lannin
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Electronic States ◽  
Orthorhombic Phase ◽  
Low Energy ◽  
Polymer Model ◽  
In Situ Raman ◽  
Intramolecular Vibrations ◽  
Two Phases

ABSTRACTIn situ Raman scattering, UPS and HREELS measurements have been used to study the fcc to orthorhombic phase transition in RbC60 thin films. Large changes in the Raman spectra are interpreted in terms of increased interfullerene coupling in the orthorhombic phase. However, the data do not support the proposed polymer model for this phase. Photoemission measurements indicate only small differences in the electronic states between the two phases in contrast with photopolymerized C60 where additional states are observed. Low energy metallic-like excitations and screening of intramolecular vibrations are observed in HREELS.

Gastric H+-K+-ATPase in situ: evidence for compartmentalization

1989 ◽  
Vol 257 (4) ◽  
pp. G539-G547
Author(s):  
S. J. Hersey ◽  
A. Perez ◽  
S. Matheravidathu ◽  
G. Sachs
Keyword(s):  
Atpase Activity ◽  
Proton Transport ◽  
Second Phase ◽  
Irreversible Inhibitor ◽  
Gastric Glands ◽  
Dependent Component ◽  
Gradient Formation ◽  
Orange Fluorescence ◽  
Two Phases

Gastric glands, isolated from rabbit, were permeabilized with digitonin to permit measurement of H+-K+-adenosinetriphosphatase (ATPase) activity and proton transport in situ. Measurement of proton gradient formation using acridine orange fluorescence showed two phases of ATP-driven proton accumulation; one phase occurs spontaneously in KCl medium and one phase requires the K+ ionophore valinomycin. Valinomycin was found to increase H+-K+-ATPase activity, indicating that the second phase is because of increased proton transport rather than a decrease in proton leak rate. The acid-activated, irreversible inhibitor, omeprazole, was used to selectively eliminate the H+-K+-ATPase molecules associated with the spontaneous component of proton transport. After omeprazole treatment a residual, valinomycin-dependent component of proton transport could be demonstrated. These results are interpreted as evidence for two compartments of H+-K+-ATPase, separated by a barrier that prevents K+ diffusion and pH equilibration. The two compartments may be separated also on the basis of anion selectivity. The spontaneously active compartment was found to be functional with various anions, including sulfate and isethionate, whereas the valinomycin-dependent component is highly selective for chloride. The proportion of H+-K+-ATPase that exists in each compartment was quantitated by measuring the fraction of total ATPase activity that could be inhibited by omeprazole in the absence and presence of valinomycin. For glands that were preconditioned with cimetidine, approximately 30% of the inhibitable enzyme was found associated with the spontaneous compartment, and this fraction increased to approximately 70% with histamine preconditioning.(ABSTRACT TRUNCATED AT 250 WORDS)

A General Strategy for Designing Two-dimensional High-efficient Layered Thermoelectric Materials

2021 ◽  
Author(s):  
Xiwen Zhang ◽  
Yilv Guo ◽  
Zhaobo Zhou ◽  
Yunhai Li ◽  
Yunfei Chen ◽  
...  
Keyword(s):  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
General Strategy ◽  
Two Dimensional ◽  
Energy Technology ◽  
The Core ◽  
High Efficient ◽  
High Figure

Two-dimensional (2D) thermoelectrics (TE) with high figure of merit (ZT > 2) is the core of the development of advanced energy technology. However, such a high ZT has never been...

scholarly journals Succession of Internal Sulfur Cycles and Sulfur-Oxidizing Bacterial Communities in Microaerophilic Wastewater Biofilms

2005 ◽  
Vol 71 (5) ◽  
pp. 2520-2529 ◽  
Author(s):  
Satoshi Okabe ◽  
Tsukasa Ito ◽  
Kenichi Sugita ◽  
Hisashi Satoh
Keyword(s):  
In Situ Hybridization ◽  
Sulfur Cycle ◽  
Rrna Gene ◽  
Second Phase ◽  
Sulfate Reducing ◽  
Sulfur Oxidizing ◽  
Reducing Activity ◽  
Two Phases ◽  
Microelectrode Measurements

ABSTRACT The succession of sulfur-oxidizing bacterial (SOB) community structure and the complex internal sulfur cycle occurring in wastewater biofilms growing under microaerophilic conditions was analyzed by using a polyphasic approach that employed 16S rRNA gene-cloning analysis combined with fluorescence in situ hybridization, microelectrode measurements, and standard batch and reactor experiments. A complete sulfur cycle was established via S0 accumulation within 80 days in the biofilms in replicate. This development was generally split into two phases, (i) a sulfur-accumulating phase and (ii) a sulfate-producing phase. In the first phase (until about 40 days), since the sulfide production rate (sulfate-reducing activity) exceeded the maximum sulfide-oxidizing capacity of SOB in the biofilms, H2S was only partially oxidized to S0 by mainly Thiomicrospira denitirificans with NO3 − as an electron acceptor, leading to significant accumulation of S0 in the biofilms. In the second phase, the SOB populations developed further and diversified with time. In particular, S0 accumulation promoted the growth of a novel strain, strain SO07, which predominantly carried out the oxidation of S0 to SO4 2− under oxic conditions, and Thiothrix sp. strain CT3. In situ hybridization analysis revealed that the dense populations of Thiothrix (ca. 109 cells cm−3) and strain SO07 (ca. 108 cells cm−3) were found at the sulfur-rich surface (100 μm), while the population of Thiomicrospira denitirificans was distributed throughout the biofilms with a density of ca. 107 to 108 cells cm−3. Microelectrode measurements revealed that active sulfide-oxidizing zones overlapped the spatial distributions of different phylogenetic SOB groups in the biofilms. As a consequence, the sulfide-oxidizing capacities of the biofilms became high enough to completely oxidize all H2S produced by SRB to SO4 2− in the second phase, indicating establishment of the complete sulfur cycle in the biofilms.

scholarly journals Review of the Recent Development in Metallic Glass and Its Composites

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1933
Author(s):  
Adit Sharma ◽  
Vladislav Zadorozhnyy
Keyword(s):  
Mechanical Properties ◽  
Metallic Glass ◽  
Metallic Glasses ◽  
Review Paper ◽  
Ex Situ ◽  
Second Phase ◽  
Glass Composites ◽  
Recent Developments ◽  
Thermo Physical Properties

Metallic glasses are known for their mechanical properties but lack plasticity. This could be prevented by combining them with other materials or by inducing a second phase to form a composite. These composites have enhanced thermo-physical properties. The review paper aims to outline a summary of the current research done on metallic glass and its composites. A background in the history, properties, and their applications is discussed. Recent developments in biocompatible metallic glass composites, fiber-reinforced metallic glass, ex situ and in situ, are discussed.

Suppression of the Phase Transition and Agglomeration of TiSi2 by Addition of Zr Element

1998 ◽  
Vol 514 ◽  
Author(s):  
Sanghyun Yoon ◽  
Hyeongtag Jeon
Keyword(s):  
Phase Transition ◽  
High Temperatures ◽  
Lower Surface ◽  
Ex Situ ◽  
Vacuum Furnace ◽  
Ion Pump ◽  
Cross Sectional ◽  
Surface And Interface ◽  
Si Substrates

ABSTRACTThe formation of C49 TiSi2 phase at high temperatures was investigated by adding the Zr contents in Ti-silicide film. Stabilizing the C49 TiSi2 phase which exhibits lower surface and interface energies than those of the C54 TiSi2 phase at high temperatures was expected to suppress the problems of Tisilicide, such as the phase transition and the film agglomeration. The thin films of Ti and Zr were codeposited (40 nm) on Si substrates in the dual e-beam evaporation system equipped with an ion pump and its base pressure of ∼5 × 10−9 torr. The amounts of Zr contents (5 and 10 atomic %) added on Tisilicide were monitored by in-situ quartz crystal monitor. Immediately after the deposition, this film was annealed by ex-situ vacuum furnace at temperatures between 600 °C and 900 °C in 100 °C increments. The identification of the phase and the chemical composition were investigated by XRD and AES, respectively. The surface and interface morphologies were examined using cross-sectional TEM. The phase transition temperature of TiSi2 was raised with increasing Zr contents. The agglomeration of TiSi2 film was also suppressed by adding Zr element and much improved interface morphologies were observed.

scholarly journals Modification of Clays by Sol-Gel Reaction and Their Use in the EthyleneIn SituPolymerization for Obtaining Nanocomposites

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
E. Moncada ◽  
R. Quijada ◽  
P. Zapata
Keyword(s):  
Phase 1 ◽  
Sol Gel ◽  
Metallocene Catalyst ◽  
Polymerization Reaction ◽  
Second Phase ◽  
Clay Particles ◽  
Nanoparticle Morphology ◽  
Two Phases ◽  
Made In

The nanocomposites formation byin situpolymerization used a metallocene catalyst (butyl-2-cyclopentadienyl zirconium 2-chlorines) and a hectorite synthetic clay type which is discussed. This research was carried out in two phases. The first phase consisted of mixing the components of the metallocenic polymerization reaction (metallocene-methylaluminoxane-ethylene) with clay in a reactor. In the second phase, the metallocenic catalytic system was supported by clay particles and then a polymerization reaction was made. In this second phase, the clay particles were modified using a sol-gel reaction with different pH values: pH = 3, pH = 8, and pH = 12. The results were compared in terms of the catalytic activity in the different systems (phase 1 and phase 2) and the nanoparticle morphology of nanocomposites generated in this study.

In situ nanostructure design leading to a high figure of merit in an eco-friendly stable Mg2Si0.30Sn0.70 solid solution

RSC Advances ◽  
2016 ◽  
Vol 6 (20) ◽  
pp. 16824-16831 ◽  
Author(s):  
Kang Yin ◽  
Xianli Su ◽  
Yonggao Yan ◽  
Ctirad Uher ◽  
Xinfeng Tang
Keyword(s):  
Phase Diagram ◽  
Solid Solution ◽  
Figure Of Merit ◽  
Binary Phase Diagram ◽  
Binary Phase ◽  
High Figure ◽  
The Relationship

The relationship between the temperature and the composition as well as the microstructure of a Sb-doped Mg2Si0.30Sn0.70 solid solution was systematically studied according to the Mg2Si–Mg2Sn pseudo-binary phase diagram.

Sign in / Sign up

Export Citation Format

Share Document