A note on BDD problems with [lamda]-gap Liu, Mingjie; Wang, Xiaoyun; Xu, Guangwu ...
Information processing letters,
01/2014, Letnik:
114, Številka:
1-2
Journal Article
Recenzirano
In CRYPTO 2009, Lyubashevsky and Micciancio presented reductions BDD... (Bounded Distance Decoding Problem) ≤ uSVP... (Unique Shortest Vector Problem) ≤ BDD..., and posed an open problem whether the ...reduction gap can be closed. This paper concerns bounded distance decoding (BDD) problems for lattices with large ...-gap. In the presence of larger ...-gap, better reductions from BDD to uSVP and exact SVP are obtained. Some result can be regarded as a partial solution to the open problem. (ProQuest: ... denotes formulae/symbols omitted.)
In this article, we provide brief overview of how mechanics and computations play a role in understanding materials growth, creating new low-dimensional materials and exploring structural defects. ...First, we introduce a concept of screw dislocation for describing carbon nanotube growth and derive a kinetic relationship between growth rate and chiral angle. Deeper analysis of the subtle balance between the kinetic and thermodynamic views reveals sharply peaked distribution of near-armchair nanotubes, explaining puzzling (n, n-1) types observed experimentally. A combination of ab initio calculations and Monte Carlo models further explains the low symmetry shapes of graphene on substrates. Being monoatomic chains of carbon, carbynes are shown to be strong yet flexible, and undergo metal-semiconductor transition under tension, offering promising innovations for future nanotechnology. We then reveal how metal substrates could facilitate the formation of boron monolayers whose bulk counterparts are non-layered and lower in energy. Further remarks are given to High Burger's vector graphene defects called D-loops and interfaces in hybrid graphene-BN materials, both with significant out-of plane distortion and impact on the mechanical properties. All of these computationally modeled systems have significant implications for the future use of these nanomaterials.
In the 21st century, the geodynamics is developing towards quantitative researches. However, due to the irreversible geological processes, it was very difficult to recover the geological process. In ...particular, the restoration of geological parameter evolution process at the microscopic scale has become a major scientific problem in geology presently. Thereby, a concept of the formation poredynamics is revised and proposed, and the formation poredynamics is a fundamental discipline which focus on the mechanical characteristic of porous media, the pore evolution law, the dynamic genesis and the seepage property of pore fluid during the burial process of clastic rocks. Moreover, it is a new interdiscipline of underground diagenetic dynamics and pore fluid dynamics, and also is as an important part of sedimentary basin dynamics. Research advances were made in both basic theory and applied research. The advances in the basic theory include: (1) the static equilibrium principle of the formation pore, (2) the porosity evolution mechanism and quantitative model of sandstone during the burial diagenetic process, (3) the compaction characteristic and the porosity evolution quantitative model of mudstone, (4) the theoretical relationship between the underground pore fluid temperature and the pore fluid pressure, (5) the influence of the tectonism-induced additional geostress on the pore fluid pressure, and (6) the relationship between the mudstone compaction and the vitrinite reflectance (Ro) of organic matter. The advances in the applied research include: (1) the geotemperature-geopressure system division of the sedimentary basin and the interpretation of the hydrocarbon distribution dynamic, (2) the modification of the strata pressure prediction model, (3) the construction of the reservoir critical properties and the reservoir dynamics evaluation system, (4) the simulation of the evolution process of the formation fluid pressure, (5) the numerical simulation and physical experimental simulation on the sandstone hydrocarbon charging dynamics, and (6) the dynamic process analysis of the hydrocarbon accumulation in tight sandstone. Through the integration between the pore genesis evolution and the pore fluid dynamic evolution, the formation poredynamics is one of the representative discipline branches that the geological dynamics research had developed toward the underground microscopic scale in recently 20 years, and it also is an inevitable result from the quantitative development of the formation and distribution mechanisms of sedimentary mineral deposits. Based on the formation poredynamics research, eight important research achievements are summarized, and the geological researches are extended from the macroscopic scale to the microscopic scale, to find out the pore parameter evolution law under control of the formation pore evolution during the burial process, and update and improve exploration and production application technologies.
Objectives: To evaluate the cardioprotective effects of trapidil on myocardial ischemia-reperfusion injury (MIRI) in rabbits.
Materials and Methods: Rabbits were subjected to 40 min of myocardial ...ischemia followed by 120 min of reperfusion. Blood for superoxide dismutase (SOD) and malondialdehyde (MDA) were estimated. At the end of reperfusion, the rabbits were sacrificed and the hearts were isolated for histological examination. An apoptotic index (AI) was determined using the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end-labeling (TUNEL) method. The expression of apoptosis-related proteins Bax and Bcl-2 was analyzed using immunohistochemistry. Statistical analyses were performed by one-way analysis of variance (ANOVA), P < 0.05 considered statistically significant
Results: Trapidil caused a significant (P < 0.05) increase in SOD activity, as decreased MDA levels and significantly (P < 0.05) reduced the expression of Bax as compared with the ischemia-reperfusion (IR) control group.
Conclusion: Trapidil may attenuate the myocardial damage produced by IR injury and offer potential cardioprotective action.
Similar reservoir sandbodies and fault conduit systems in the sandstone reservoirs in the middle Essub 3 member of the Niuzhuang Sag have been problematic for a long time. The following problems ...remain unsolved: 1) The distribution of sandstone porosity is inconsistent with the hydrocarbon accumulation. The oil sandstones have low porosity instead of high porosity. 2) Sandstones, which have the same properties, have different levels of oiliness, and the sandstones with almost the same properties show different degrees of oil-bearing capacity. This study analyzes the condition of reservoirs in the research area during the accumulation period in terms of paleoporosity estimation and discusses the critical porosity of the sandstone reservoirs during the same period. Consequently, the hydrocarbon mainly accumulates in high porosity belts. Paleoporosity during the accumulation period is found to be a vital controlling factor. Therefore, high paleoporosity sandstones in the middle Essub 3 member of the Niuzhuang Sag have great potential for future exploration.
A fabrication strategy for biphasic gels is reported, which incorporates high‐internal‐phase emulsions. Closely packed micro‐inclusions within the elastic hydrogel matrix greatly improve the ...mechanical properties of the materials. The materials exhibit excellent switchable mechanics and shape‐memory performance because of the switchable micro‐ inclusions that are incorporated into the hydrogel matrix. The produced materials demonstrated a self‐healing capacity that originates from the noncovalent effect of the biphasic heteronetwork. The aforementioned characteristics suggest that the biphasic gels may serve as ideal composite gel materials with validity in a variety of applications, such as soft actuators, flexible devices, and biological materials.
Zeit für Veränderungen: Dicht gepackte schaltbare Mikroeinschlüsse in einer Hydrogelmatrix ergeben biphasige synergistische Gelmaterialien mit schaltbarer Mechanik, Selbstheilungs‐ und Formgedächtniseigenschaften.
Molybdenum carbide–graphene hybrid constituting few‐layer graphene and molybdenum carbide nanoparticles is synthesized by carburizing molybdenum disulfide atomic layer substrate. At the elevated ...temperature and reducing environment, molybdenum disulfide is reduced to molybdenum acting as the catalyst for graphene growth, while simultaneously molybdenum atoms are carburized to form molybdenum carbide. This hybrid has potential applications in heterogeneous catalysis.
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