Optimization Design for the Electron Emission System Using Improved Powell Method

The electron emission system, which may mostly decide the main properties of the whole electron optical system, is a crucial element for an electron gun. The design of the electron emission system is more important compared with other electron lenses in the electron gun. In this paper, an optimization design method for the electron emission system is presented by using an Improved Powell Method with linear search for the one dimensional search. The optimal structure parameters with a criterion of minimum objective function value for this system are provided. The computed results may show that this direct search optimization method is feasible and useful for the optimal design of the electron emission system as well as other electron optical systems

Experimental Research on Foamed Mixture Lightweight Soil Mixed with Fly-Ash and Quicklime as Backfill Material behind Abutments of Expressway Bridge

To promote the utilization of fly-ash, based on the orthogonal experiment method, wet density and unconfined compressive strength of Foamed Mixture Lightweight Soil mixed with fly-ash and quicklime (FMLSF) are studied. It is shown that the wet density and unconfined compressive strength of FMLSF increase with the increase of cement content, while decreasing with the increase of foam content. With the mixing content of fly-ash increase, the wet density and unconfined compressive strength of FMLSF increase firstly and then decrease. Scanning Electron Microscope (SEM) tests show that ball effect or microaggregate effect of fly-ash improves the wet density and unconfined compressive strength of FMLSF. With the mixing content of quicklime increase, the wet density and unconfined compressive strength of FMLSF increase firstly within a narrow range and then decrease. In addition, the primary and secondary influence order on wet density and 28-day compressive strength of FMLSF are obtained, as well as the optimal mixture combination. Finally, based on two abutments in China, behind which they are filled with FMLSF and Foamed Mixture Lightweight Soil (FMLS), the construction techniques and key points of quality control behind abutment are compared and discussed in detail, and the feasibility of utilization fly-ash as FMLSF is verified by the experimental results

Production and Radioprotective Effects of Pyrroloquinoline Quinone

Pyrroloquinoline quinone (PQQ) was produced by fermentation of the Methylovorus sp. MP688 strain and purified by ion-exchange chromatography, crystallization and recrystallization. The yield of PQQ reached approximately 125 mg/L and highly pure PQQ was obtained. To determine the optimum dose of PQQ for radioprotection, three doses (2 mg/kg, 4 mg/kg, 8 mg/kg) of PQQ were orally administrated to the experimental animals subjected to a lethal dose of 8.0 Gy in survival test. Survival of mice in the irradiation + PQQ (4 mg/kg) group was found to be significantly higher in comparison with the irradiation and irradiation + nilestriol (10 mg/kg) groups. The numbers of hematocytes and bone marrow cells were measured for 21 days after sublethal 4 Gy gamma-ray irradiation with per os of 4 mg/kg of PQQ. The recovery of white blood cells, reticulocytes and bone marrow cells in the irradiation + PQQ group was faster than that in the irradiation group. Furthermore, the recovery of bone marrow cell in the irradiation + PQQ group was superior to that in irradiation + nilestriol group. Our results clearly indicate favourable effects on survival under higher lethal radiation doses and the ability of pyrroloquinoline quinine to enhance haemopoietic recovery after sublethal radiation exposure

A study of the inclusion complex formed between cucurbit[8]uril and isonicotinic acid

The complexation between cucurbit[8]uril, Q[8], and isonicotinic acid has been studied using 1H NMR spectroscopy, UV–Vis absorption spectroscopy, Raman spectroscopy and single crystal X-ray diffraction. The results revealed that the 2:1 inclusion complex (4-PA)2@Q[8]·25H2O is formed, with two guests simultaneously encapsulated in the hydrophobic cavity; the mean planes of the guests are 3.535 Å apart. Graphical abstract: [Figure not available: see fulltext.

Comparison of the subjective satisfaction of the donor site morbidity : free radial forearm flap versus anterolateral thigh flap for reconstruction in tongue cancer patients

The purpose of the study was to compare the differences of the subjective satisfaction of the donor site morbidity between the free radial forearm flap (FRFF) and anterolateral thigh flap (ALTF) for tongue reconstruction. One hundred and nineteen patients underwent FRFF or ALTF reconstruction were retrospectively evaluated by a standardized self-established donor site morbidity questionnaire which included 5 domains, sensibility, movement disabilities, cosmetics, social activities and general impacts on the quality of life. The Cronbach?s coefficient alpha of the questionnaire was 0.707. The exploratory factor analysis revealed that the 5 items of the questionnaire might load onto two distinct subscales. Patients with ALTF had higher scores in the sensibility, cosmetics and the composite score (P 0.05). ALTF has the advantage of better results of donor site morbidity, such as sensibility and cosmetics, over FRFF

Transient Protection from Heat-Stress Induced Apoptotic Stimulation by Metastasis-Associated Protein 1 in Pachytene Spermatocytes

Deregulated thermal factors have been frequently implicated in the pathogenesis of male infertility, but the molecular basis through which certain responses are directed remain largely unknown. We previously reported that overexpression of exogenous Metastasis-associated protein 1 (MTA1) protects spermatogenic tumor cells GC-2spd (ts) against heat-induced apoptosis. To further dissect the underlying mechanism, we addressed here the fine coordination between MTA1 and p53 in pachytene spermatocytes upon hyperthermal stimulation. interference of MTA1 expression in the testes of C57BL/6 mice also urged an impairment of the differentiation of spermatocytes and a disruption of Sertoli cell function due to the elevated apoptotic rate after heat stress. Finally, attenuated expression of MTA1 of pachytene spermatocytes was observed in arrested testes (at the round spermatid level) of human varicocele patients.These data underscore a transient protective effect of this histone modifier in primary spermatocytes against heat-stress, which may operate as a negative coregulator of p53 in maintenance of apoptotic balance during early phase after hyperthermal stress

Experimental study and weighting analysis of factors influencing gas desorption

Gas is one of the necessary contributing factors for coal and gas outburst accidents, and the gas desorbed in coal is the energy carrier in the outburst process. The study of gas desorption laws is the premise and basis for gas content determination and gas accident prevention. To solve the problem of inaccurate gas content measurement due to the unclear characteristics of rapid gas desorption in 0–10 s, the gas desorption experimental device was improved, the influence factors of gas desorption were studied experimentally, and a comprehensive analysis method was proposed based on the gas desorption rate, gas desorption efficiency, initial gas desorption amount and total desorbed gas. The experiment analysed five factors that affected gas desorption, including the degree of metamorphism, type of failure, particle size, pressure and temperature. The results show that there is a monotonically decreasing power function relationship between the initial gas desorption rate and time and a monotonically increasing logarithmic function relationship between the gas desorption amount and time; the curve has a limit value. The gas desorption amount is large in 0–10 s and increases slowly afterwards. Among the factors affecting gas desorption, their importance decreases in the order of pressure > metamorphism > particle size > failure type > temperature. This study is of great practical value for the calculation of gas losses in gas content determination, and the resulting gas desorption laws are of great importance in guiding gas control work