Effect of the fuel-air flow velocity on heat release rate of swirling non-premixed methane flames

A laboratory-scale gas turbine model combustor fueled with methane is studied experimentally with the aid of three-dimensional computed tomography of chemiluminescence (3D-CTC) and high speed (5 kHz) chemiluminescence imaging. Various fuel-lean operating conditions were tested to investigate the impact of flow velocity on heat release rate oscillation and spatial structure transition with fixed global equivalence ratio of about 0.65 and dump plane velocity of 2.9-18.3 m/s. In the study of combustion structure transition, the three-dimensional relative emissions of CH* were measured and taken as qualitative indicators of the heat release rate. This 3D measurement method utilizes CH* images from 8 directional as inputs combined with tomographic algorithms to compute the 3D distribution of CH* CL intensities. For all tested conditions, pronounced extension of inner recirculation zone (IRZ) along the nozzle is observed under the attached (V-shaped) swirl stabilized flames. During the increase of Reynolds number, the heat release zone changing obviously along the nozzle radial and axis direction, and the largest heat release plane moves downstream significantly. In addition, an intensified high-speed camera was adopted for the heat release dynamics study. Strong oscillations appeared in the flame zone that significantly affected the total heat release oscillations, and oscillation increases with the raise of Reynolds number. (C) 2019 Elsevier Masson SAS. All rights reserved

功率分流渐开线花键副齿向载荷分配规律研究

以功率分流系统中的两种典型渐开线花键副为研究对象，分别建立了纯转矩作用下齿向载荷分配系数的解析模型，研究了载荷作用位置、转矩分配和花键扭转刚度对齿向载荷分配的影响。结果表明，对于第一种渐开线花键副，随着齿向载荷分配位置和载荷分配比例的增加，最大载荷分配系数先减小后增加，存在最优载荷作用位置和最优载荷分配比例，使最大齿向载荷分配系数达到最小，减小比例分别为56.67%和51.83%；当左侧扭转刚度为450×106 N/rad且右侧扭转刚度为522×106 N/rad时，最大载荷分配系数达到最小值2.08；对于第二种渐开线花键副，随着左侧转矩位置的增加，最大载荷分配系数逐渐增加，增加比例为14.36%；而载荷分配对最大载荷分配系数的影响很小；随着扭转刚度的增加，最大载荷分配系数呈线性比例增加，增加比例为16.86%

避免激光晶体结露的水冷控制方法

 一种避免激光晶体结露的水冷控制方法,包括如下步骤：步骤1：首先开启控制水温系统程序；步骤2：控制水温系统程序自动检测空气的温度、湿度和冷却水的初始温度,并存入程序的环境状态参数中；步骤3：在控制水温系统程序中输入工作状态参数；步骤4：运行控制水温系统程序,输出水温下降阶段数控制信号；步骤5：水冷机分阶段制冷,以避免激光器晶体棒结露

RESPONSE OF GUT BACTERIAL COMMUNITY IN BLACK SEA BREAM TO DIFFERENT FEATHER MEAL IN FEED

Feather meal is a potential protein source of high nutritional value. Adding a moderate amount of feather meal into animal feed not only reduces the cost for feed but also helps re-utilizing wastes. The microbial community in the animal gut may be functionally adapted to available resources, thus play an important role in degradation and absorption of feather meal. However, little is known about the effect of feather meal amendment on the diversity and community structure of intestinal microbes in mariculture. We investigated the influence of the feather-amended meal(5%)on gut bacteria of black sea bream(Acanthopagrus schlegelii). Before adding to the meal, feather was hydrolyzed(FH),acid-treated(FA), puffed(FP), or used as raw feed(FO). Fish meal(FN)and commercially-sold feed(FS)were taken as the control. After feeding for 12 weeks, the gut bacterial diversity and communities were assessed using 16S rRNA high throughput sequencing. In general, the feather-amended treatments had significantly lower bacterial alpha diversities(OTU richness, Simpson and Shannon indices), and significantly different community structure, compared with the control. The relative abundances of Bacteroidia, Clostridia, Deltaproteobacteria, Oxalobacteraceae, and Ralstonia were significantly lower in the feather-amended treatments than in the control. There were also differences between feather-amended treatments of various styles:the proportions of Proteobacteria, Gammaproteobacteria, Oceanospirillales, Halomonadaceae,and Halomonas in the FO treatment were significantly lower than that in the FH; the proportion of Bacillales in the FO was significantly higher than that in the FN, while the proportions of Bacteroidetes, Oxalobacteraceae and Ralstonia were significantly lower. In addition, The FO treatment tended to have a higher abundance ratio of Firmicutes to Proteobacteria(7.42)than the FN(0.97)and FH(0.74). The proportions of Porphyromonadaceae and Treponema in the FN treatment were significantly higher than that in the FH. Nevertheless, Halomonas appeared to be much lower in the FN than in the FH.</p

宁夏固原云雾山草原自然保护区生态建设的研究

十年来，根据保护区的特点，已摸索出一整套保护区建设的途径与技术；在总体规划经营上，建立了比较严密的保护管理体系,核心区已建成较合理的草原自然生态系统，试验区的植被基本得到恢复；在综考的基础上，科研以旱地建设为目标，摸索出了半干旱黄土丘陵区草场恢复改良的途径与技术,先后引进筛选优良牧草20种,其中沙打旺。红豆草等8种已得到大面积推广种植,并在野生沙打旺特性及引种驯化方面的研究取得了突破性进展

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies