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1.
2.
Synchronization of signal packets is required in networks in order to route the packets. Due to changes in the interarrival times of the packets the inputs to the routing circuits may exhibit oscillatory metastability. Oscillatory metastability can be eliminated in optical circuits by the addition of logic signal stretch. This can be done because the propagation time of optics can be precisely controlled. An algorithm for inserting logic signal stretch to eliminate oscillatory metastability is presented herein. 相似文献
3.
Negar Naghavi Solange Temgoua Thibaud Hildebrandt Jean Franois Guillemoles Daniel Lincot 《Progress in Photovoltaics: Research and Applications》2015,23(12):1820-1827
The purpose of the present paper is to focus on the impact of oxygen gas partial pressure during the sputtering of i‐ZnO and ZnMgO on the transient behavior of Cu(In,Ga)Se2 (CIGSe) based solar cells parameters when a CBD‐Zn(S,O) buffer layer is used. Based on electrical characterization of cells, it is observed that the effect of light soaking is different on J–V characteristics depending on whether oxygen is or is not present during the first deposition time of the i‐ZnO or ZnMgO layers. In fact, when cells are prepared with standard i‐ZnO, the efficiencies are very low and a pronounced transient behavior is observed. However, when the first 10 nm of i‐ZnO or ZnMgO is formed by sputtered layer without adding oxygen during the process, depending on the thickness of the buffer layer, the transient effects strongly decreases. It is then possible to get stable cells reaching efficiencies quite similar to the CdS reference cells, especially with ZnMgO, without any post‐treatments. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
4.
某些无放射性的具有自旋特性的惰性气体同位素(如^3He和^129Xe),可通过激光抽运超极化,得到很高的非热平衡极化度和长驰豫时间的惰性气体。极化后惰性气体同位素核磁共振的灵敏度提高10^3~10^5倍。介绍了目前极化惰性气体常用的两种方法——自旋交换光抽运和亚稳态能级交换。 相似文献
5.
D. Behera N. C. Mishra K. Patnaik 《Journal of Superconductivity and Novel Magnetism》1997,10(1):27-32
A series of samples of YBa2Cu3-xAgxO7-y with 0≤x≤0.12 composition was studied to probe into the Ag substitution effect on oxygen stoichiometry, lattice parameters,
and superconducting properties. With the samples prepared at a relatively lower sintering temperature, Ag could be doped in
the grains rather than precipitate at grain boundaries. Thus, unlike in the case of YBCO + Ag composites or in doped systems
annealed at high temperatures where Ag occupies mostly the grain boundary, the present system showed a drastic change inT
c, oxygen stoichiometry, and lattice parameters with Ag concentration, indicating the substitution of Ag at the Cu(l) sites
in the grains. The stable 2-fold oxygen coordination of Ag substituting Cu(l)’s explains the observed variation of oxygen
deficiency with Ag. A crystallochemical analysis has been made to reveal the crucial role of Ag-substitution-induced coordination
incompatibility and charge state instability on carrier concentration andT
c. 相似文献
6.
Lauren M. Garten Shyam Dwaraknath Julian Walker John S. Mangum Paul F. Ndione Yoonsang Park Daniel A. Beaton Venkatraman Gopalan Brian P. Gorman Laura T. Schelhas Michael F. Toney Susan Trolier‐McKinstry Kristin A. Persson David S. Ginley 《Advanced materials (Deerfield Beach, Fla.)》2018,30(25)
Many technologically critical materials are metastable under ambient conditions, yet the understanding of how to rationally design and guide the synthesis of these materials is limited. This work presents an integrated approach that targets a metastable lead‐free piezoelectric polymorph of SrHfO3. First‐principles calculations predict that the previous experimentally unrealized, metastable P4mm phase of SrHfO3 should exhibit a direct piezoelectric response (d33) of 36.9 pC N?1 (compared to d33 = 0 for the ground state). Combining computationally optimized substrate selection and synthesis conditions lead to the epitaxial stabilization of the polar P4mm phase of SrHfO3 on SrTiO3. The films are structurally consistent with the theory predictions. A ferroelectric‐induced large signal effective converse piezoelectric response of 5.2 pm V?1 for a 35 nm film is observed, indicating the ability to predict and target multifunctionality. This illustrates a coupled theory‐experimental approach to the discovery and realization of new multifunctional polymorphs. 相似文献
7.
Baomin?Liang Yuping?Shi Richard?W.?HartelEmail author 《Journal of the American Oil Chemists' Society》2003,80(4):301-306
As complex lipid systems, the phase and crystallization behavior of mixtures of a high-melting milk fat fraction with a low-melting
milk fat fraction or canola oil was studied. A turbidity technique was developed to estimate solubility and metastability
conditions of these lipid mixtures. Both solubility and metastability of the high-melting milk fat fraction in liquid lipids
increased exponentially with temperature. At a given equilibration temperature, liquid phases and solid fractions with nearly
identical melting profiles and TAG compositions were obtained regardless of the original concentration of the lipid mixture.
The maximum melting temperature (MMT), as measured by DSC, of the liquid phase increased dramatically in the equilibrium temperature
range of 27.5–35.0°C but did not change at temperatures below and above this range (down to 25.0°C and up to 40°C in this
study). The content of long-chain TAG (C46−C52) increased and short-chain TAG (C36−C40) decreased in the liquid phases as the equilibrium temperature increased. A plot of the TAG group ratio (i.e, long-short-chain
TAG) vs. equilibrium temperature was generated to illustrate the phase behavior of the complex lipid system and to represent
a solubility curve, from which the supersaturation level for crystallization kinetics was determined. Higher supersaturation
and lower temperature resulted in higher nucleation and crystallization rates. Compared to the system with a low-melting milk
fat fraction, mixtures of the high-melting milk fat fraction with canola oil had higher nucleation and crystallization rates
due to the lower solubility found for this system. 相似文献
8.
Michael L. Whittaker Wenhao Sun Karen A. DeRocher Saivenkataraman Jayaraman Gerbrand Ceder Derk Joester 《Advanced functional materials》2018,28(2)
Metastable amorphous precursors are emerging as valuable intermediates for the synthesis of materials with compositions and structures far from equilibrium. Recently, it was found that amorphous calcium barium carbonate (ACBC) can be converted into highly barium‐substituted “balcite,” a metastable high temperature modification of calcite with exceptional hardness. A systematic analysis ACBC (Ca1‐xBaxCO3·1.2H2O) in the range from x = 0–0.5 is presented. Combining techniques that independently probe the local environment from the perspective of calcium, barium, and carbonate ions, with total X‐ray scattering and a new molecular dynamics/density functional theory simulations approach, provides a holistic picture of ACBC structure as a function of composition. With increasing barium content, ACBC becomes more ordered at short and medium range, and increasingly similar to crystalline balcite, without developing long‐range order. This is not accompanied by a change in the water content and does not carry a significant energy penalty, but is associated with differences in cation coordination resulting from changing carbonate anion orientation. Therefore, the local order imprinted in ACBC may increasingly lower the kinetic barrier to subsequent transformations as it becomes more pronounced. This pathway offers clues to the design of metastable materials by tuning coordination numbers in the amorphous solid state. 相似文献
9.
在跨时钟域传递数据的系统中,常采用异步FIFO(First In First Out,先进先出队列)口来缓冲传输的数据,以克服亚稳态产生的错误,保证数据的正确传输。但由于常规异步FIFO模块中的RAM存储器读写寻址指针常采用格雷码计数器以及“空满”控制逻辑的存在,将使通过这两个模块的信号通路延时对整个模块的工作频率造成制约。提出了一种在FPGA内实现高速异步FIFO的方法,该方法针对不可能产生满信号的高频系统,通过省略“满”信号产生模块和多余的存储器位深来简化常规的FIFO模块,而只保留“空”信号产生模块。仿真和综合设计结果表明,整个模块的工作频率得到一定提高。 相似文献
10.
Physical aspects of explosive compaction of alumina nanopowders with different phase compositions are studied experimentally.
Physical processes that occur during consolidation of nanoparticles under pulsed loading are considered. Conditions of retaining
of the material nanostructure after compaction and subsequent low-temperature sintering are determined. Physicomechanical
properties of explosive compacts and ceramics on the basis of these compacts are studied. A ceramic material characterized
by a nanostructure (grain size of ≈200 nm) and high values of density (97% of the theoretical value) and microhardness (up
to 23.5 GPa) is obtained.
__________
Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 6, pp. 114–126, November–December, 2008. 相似文献