Optimized thermoelectric properties of Mo_3Sb_(7-x)Te_x with significant phonon scattering by electrons

Heavily doped compounds Mo_3Sb_(7−x)Te_x (x = 0, 1.0, 1.4, 1.8) were synthesized by solid state reaction and sintered by spark plasma sintering. Both X-ray diffraction and electron probe microanalysis indicated the maximum solubility of Te was around x = 1.8. The trends in the electrical transport properties can generally be understood using a single parabolic band model, which predicts that the extremely high carrier concentration of Mo_3Sb_7 (~10^(22) cm^(−3)) can be reduced to a nearly optimized level (~2 × 10^(21) cm^(−3)) for thermoelectric figure of merit (zT) by Te-substitution with x = 1.8. The increased lattice thermal conductivity by Te-doping was found to be due to the decreased Umklapp and electron–phonon scattering, according to a Debye model fitting. The thermoelectric figure of merit (zT) monotonously increased with increasing temperature and reached its highest value of about 0.51 at 850 K for the sample with x = 1.8, making these materials competitive with the state-of-the-art thermoelectric SiGe alloys. Evidence of significant electron–phonon scattering is found in the thermal conductivity

Research on damping parameter identification of elastomer buffer

The object of this paper is the changing process of damping force as the falling weight impacting the elastomer buffer. The whole mechanical system is built up through practical test and simulation. According to the type of elastomer buffer and the experimental process in shock environment, velocity damping force identification model was established. Wavelet denoising and least square method were used for parameter identification of damping force. Considering the data saturation problem in the traditional least square method, the limited memory least square method was obtained to improve the identification method. The results of parameter identification of damping force based on limited memory method proved that the limited memory method was superior to least square method. The numerical results demonstrate the effectiveness of the identification model

Experimental study on a certain elastomer buffer with dynamic identification method

The damping force of elastomer buffer in shock environment is the research object of this paper. The impact experiment and data simulation are used to understand the whole mechanical system. Equation with velocity and damping force is used for modeling according to the specific type of the elastomer buffer. The data of velocity and damping force is obtained by experimental data collection and pretreatment. Genetic algorithm is used to identify parameters according to the time invariant feature of traditional model. Through the results of parameter identification by genetic algorithm it seems that the parameters have the time-varying characteristics. Therefore, time-varying method is used for parameter identification. Limited memory method, which is obtained by the improvement of traditional least square method, is used for time-varying parameter identification. And the fitting accuracy of the identification results is better than that of genetic algorithm. The numerical results prove that the model is effective and parameters are time-varying

Quark Mass Ratios in ChPT with the Difference of Quark Condensates Considered

The chiral effective Lagrangian for pseudoscalar nonet is constructed in consideration of isospin breaking. And the difference of quark condensates is taken accounted. The SU(3) singlet eta0 is not taken as Goldstone-boson. The mixing with and without isospin symmetry is considered. The quark mass ratios are obtained through solving the mass equations of mesons. We estimate the change of quark mass ratios according to the change of the masses of pion+ and kaon+ to see how the electromagnetic corrections affect our results. It turn out that massless up quark is possible. The upper limit for mu/md is around 0.39. 2ms/(mu+md)=24.23~25.12. The values for quark condensate ratios and other constants are limited in narrow ranges.Comment: 10 page

Genome cloning and genetic diversity of Apple chlorotic leaf spot virus

514-519Apple chlorotic leaf spot virus (ACLSV) with a wide distribution and variability is great threat to apple yield and quality. The systematic research on the occurrence, genetic structure and evolutionary mechanism is important for the prevention of ACLSV. In this study, 360 apple leaf samples were collected from Shanxi province and tested by RT-PCR, and the result showed that the incidence of ACLSV in Shanxi was ranged from 43.59% in Linfen to 68.18% in Wanrong. One new ACLSV isolate (shanxi14-MK368727) was collected from the positive samples, of which the genome (including the 5' and 3' ends) was 7507 bp and encoded 2536 amino acids. Compared with online database, the highest nd identity was between shanxi14 and KJ522693.1, and the lowest was shanxi14 and M58152.1. Phylogenetic analyzed based on genome showed that 25 isolated of ACLSV were divided two groups (Group I and II), which showed that was no significant correlation with geographic location. The selection pressures of POL, MP and CP were tested, the result proved the three genes were under negative selection pressure. The knowledge presented in this study will be useful in for the design of long-term, sustainable management strategies for controlling these viruses

Expression of Cripto-1 in the placenta and its role in placenta accreta and placenta previa

Objectives: This study Aims to explore the role of placental Cripto-1 in the incidence of an adherent placenta.  Material and methods: Ten pregnant women with placenta increta, 20 pregnant women with placenta previa and 30 women with normal pregnant were enrolled in this study. Reverse transcription-polymerase chain reaction (RT-PCR) was used to measure the expression of Cripto-1 in the placenta while as the analysis of placental Cripto-1 was performed by Western blotting  Results: The placenta increta group showed higher levels of Cripto-1 in the center of the increta as compared to the non-implantation area. The level of placental Cripto-1 in the placenta increta was higher than that of the placenta accrete. The expression of placental Cripto-1 in the placenta increta and placenta previa groups was higher than that of control.  Conclusions: Placental Cripto-1 is involved in the regulation of placental tissue invasion. Additionally, excessive placental growth or penetration into the myometrium are likely to be involved in the development of placenta increta.