EXPERIMENTAL STUDY ON DARCY′S LAW IN HELE-SHAW CELLS

The basic physics of unsteady Hele-Shaw flow at high Reynolds numbers is mainly studied by an experimental measurement. In order to confirm the Darcy′s law in Hele-Shaw cell, since there is an analogy between flow in cells and that in porous media, progressive water waves are utilized to build an unsteady flow in a Hele-Shaw cell, and which complex wave number is measured by a wave height gauge. Meanwhile, theoretical analyses are used to compare with experimental data. Result shows Darcy′s Law is not exactly correct for unsteady Hele-Shaw flows, and it is expected to conduct a modified Darcy′s Law.

Forecast correct model of overpressure attenuation during gas explosion in excavation roadway

Through analyzing experimental data of gas explosions in excavation roadwaysand the forecast models of the literature, Found that there is no direct proportional linearcorrelation between overpressure and the square root of the accumulated volume of gas,the square root of the propagation distance multiplicative inverse.Also, attenuation speedof the forecast model calculation is faster than that of experimental data.Based on theoriginal forecast models and experimental data, deduced the relation of factors by introducinga correlation coefficient with concrete volume and distance, which had been verifiedby the roadway experiment data.The results show that it is closer to the roadway experimentaldata and the overpressure amount increases first then decreases with thepropagation distance.

Study on B_d→φK_s Decay in EDQS Model

We study Bd → φKs decay in extra down-type quarks （EDQS） model with a non-universal Z boson associated with flavor changing neutral currents （FCNCs） at the tree level. With the up-to-date experimental data of Br（Bd → φKs）, SCKs, and ACKs, we derive the bounds on the Z-b-s coupling parameter ｜Ubs ｜ and the new weak phase φ, using the constrained parameter spaces, we finally give predictions for Bd → φφ decay, which could be tested at the Fermilab Tevatron and the LHC-b experiments.

Research on the direct damage-based seismic design method of RC frame structures

Based on the existing research, this paper presents an innovative methodology to realize direct damage-based seismic design for RC frame structures by mobilizing ESDOF theory and the damage-based strength reduction factor（RD factor）. A design example is then followed to verify this method.

两位一步除法

两位一步除法厉晋元一除商两位，熟练后能使除法速度提高５０％到１００％（一倍），毋庸讳言难度也有所增加。关键在于迅速估出初商两位，再做两位乘两位的乘减，以下先讲一讲一除商两位的运算要领和具体算法步骤。（一）以除头被首估商结合除首两位数估商为主进行估商。...

Branching fractions and direct C P asymmetries of ■_s →K^0h^+h′^-(h(′)=K,π) decays

Motivated by the recent LHCb collaboration measurements of charmless three-body decays of Bs-0 meson, we calculate the branching fractions of Bs→K0h＋h＇-（h（＇）=K,π）decay modes using the factorization approach.Both the resonant and nonresonant contributions are studied in detail. For the decays Bs→K0h＋h＇-（h（＇）=K,π） and Bs→K0h＋h＇-（h（＇）=K,π）our resultsagree well with experimental data, and the former is dominated by the K＊, while the latter one is dominated by the nonresonant con-tribution. Considering the flavor S U（3） symmetry violation, the sum of branching fractions of Bs→K0h＋h＇-（h（＇）=K,π）could accommodate the data well too. It should be noted that both branching fractions are sensitive to the scalar density （Kπ｜sq｜0））. Furthermore, the resonant contributions are dominated by the scalar K;（1430）. We hope that these branching fractions could be measured individually in the experiments so as to test the factorization approach and the flavor S U（3） asymmetry. Moreover, the direct CP asymmetries of these decays are also investigated, which could be measured in the running LHCb experiment and Super-b factory in the future.

No evidence for female discrimination against male house mice carrying a selfish genetic element

Meiotic drivers distort transmission to the next generation in their favor, with detrimental effects on the fitness of their homologues and the rest of the genome. Male carriers of meiotic drivers commonly inflict costs on their mates through genetic incompatibility, reduced fecundity, or biased brood sex ratios. Given these costs, evidence for female discrimination against male carriers is surprisingly rare. One of few examples is the t haplotype in house mice, a meiotic driver that shows strong transmission distortion in males and is typically homozygote lethal. As a consequence, mating between 2 t heterozygous （＋/t） mice leads to high embryo mortality. Previous experiments showing that＋/t females avoid this incompatibility cost by preferring ＋/＋ versus ＋/t males have inferred preference based on olfactory cues or brief social interactions. Evidence from mating contexts in laboratory settings and semi-natural populations has been inconclusive. Here, we investigated female choice from a large number of no-choice mating trials. We found no evidence for discrimination against＋/t males based on mating, remating, and copulatory behavior. Further, we found no evidence for avoidance of incompatibility through selective interactions between game- tes. The likelihood of mating showed significant effects of female weight and genotype, suggesting that our test paradigm enabled females to exhibit mate choice. We discuss the strengths and limitations of our approach. By explicitly considering selection at both the individual and gene level, we argue why precopulatory female discrimination by＋/t females may be less evolutionarily stable than discrimination by all females based on postcopulatory mechanisms.

Wind characteristics near the ground during typhoon Meari

Wind speed and direction data during typhoon Meari were obtained from eight anemometers installed at heights of 10, 20, 30, and 40 m on a 40-m tower built in the Pudong area of Shanghai. Wind-turbulence characteristics, including wind-speed profile, turbulence integral scale, power spectra, correlations, and coherences were analyzed. Wind-speed profiles varied with time during the passage of Meari. Measured wind-speed profiles could be expressed well by both a power law and a log law. Turbulence integral scales for u, v, and w components all increased with wind speed. The ratios of the turbulence scales among the turbulence components averaged for all 10-min data were 1：0.69：0.08 at 10 m, 1：0.61：0.09 at 20 m, and 1：0.65：0.13 at 40 m. The turbulence integral scales for the u and v components increased with average gust time, but the turbulence integral scale for the w component remained almost constant when the gust duration was greater than 10 min. The decay factor of the coherence function increased slightly with wind speed, with average values for longitudinal and lateral dimensions of 14.3 and 11.3, respectively. The slope rates of the turbulence spectra in the inertial range were less than -5/3 at first, but gradually satisfied the Kolmogorov 5/3 law. The longitudinal wind-power fluctuation spectrum roughly fitted the von Karman spectrum, but slight deviations occurred in the high-frequency band for lateral and vertical wind-power fluctuation spectra.