喷吹神东高钙烟煤对高炉回旋区热状态的影响

高炉风口和回旋区的热状态对炉内煤气流的一次分布具有重要影响,进而影响高炉的经济技术指标。为探究喷吹神东高钙烟煤对高炉回旋区热状态的影响,本文通过收集某钢铁企业试烧期间高炉鼓风参数及其他各项操作参数,采用Fluent仿真模拟方法,建立风口回旋区的三维燃烧模型,系统分析不同喷吹条件下温度分布、气体分布、速度分布的变化规律,从而确定在风口复杂条件下喷吹神东高钙烟煤对高炉回旋区热状态的影响。模拟计算结果表明:神东高钙烟煤和ES无烟煤燃烧后产生的还原气体量最多,生产时有利于矿石的还原;向高炉喷吹神东高钙烟煤、HX烟煤、WN烟煤、SG烟煤与ES无烟煤混合煤粉时,燃尽率分别为72.25%、70.11%、68.87%、67.56%,神东高钙烟煤与ES无烟煤混合喷吹时煤粉的燃尽率最高,这是由于神东高钙烟煤和ES无烟煤的CaO质量分数较高,其在风口、回旋区内的燃烧特性最佳;混合喷吹神东高钙烟煤与ES无烟煤时,风口、回旋区内的煤气成分和煤粉燃尽率等方面要强于其他三种情况,适宜向高炉喷吹。

滚珠丝杠滚道法向截面测量系统

为了实现滚珠丝杠滚道法向截面的快速、精确和无损检测,建立基于光学测微计的滚珠丝杠滚道法向截面测量系统。基于滚珠丝杠滚道法向截面测量原理设计了检测装置,对原有滚道法向截面数据处理算法进行优化,提出了角度划分圆弧方法、圆弧数据均匀化方法。对检测装置中传感器安装误差、水平移动平台直线度误差、传感器误差进行分析,并进行误差补偿。最后,通过实验验证检测装置和优化后的算法组成的整个检测系统的精度。实验结果表明:算法优化后检测系统测得的滚道法向截面参数,随着划分圆弧的角度增加最终收敛。算法优化后检测系统测得的圆弧半径和接触角与厂家提供的误差最大值分别为3.6μm和19′31″,相对算法优化前提升率分别为64.36%和53.46%;测得的圆弧半径和接触角标准偏差最大值分别为1.56μm和2′41″,相对算法优化前提升率分别为22.77%和56.67;测得的圆弧半径和接触角的A类不确定度最大值分别为0.63μm和1′6″,相对于算法优化前分别降低56%和70%。滚道法向截面检测系统的精度、重复性和不确定度均满足测量要求。

某变速箱用内圈单挡边圆柱滚子轴承疲劳断裂失效分析

某变速箱整机试验运转30h后,变速箱用圆柱滚子轴承内圈发生断裂。对轴承内圈断口进行观察,并采用化学成分分析、金相组织检验及洛氏硬度检验等技术对内圈剥离原因进行了分析,同时采用仿真计算软件对试验工况进行了分析。结果表明:轴承原材料无明显缺陷,但经仿真计算发现轴承滚道发生边缘应力集中,且由于NJ结构内圈单挡边无轴向固定,滚动体与轴承中心轴向偏移0.25 mm后,边缘接触应力超过极限要求,致使内圈滚道边缘率先发生剥落,逐步扩展并断裂。

新型总线技术——RACEway和RapidIO概述

从传统的总线技术开始，主要介绍了两种新型的总线技术：RACEway和RapidIO及二者的比较，并探讨了其在实时应用系统中的未来发展趋势。

从风口回旋区模拟谈风口参数对风量的影响

基于鞍钢新5号高炉生产数据,在考虑风口回旋区条件下,探讨了风口回旋区体积、风口直径及风口插入深度对风量的影响。结果表明:风口回旋区体积由0.6769m^(3)增大到0.7186m^(3)时,风量从158.02m^(3)/min增加到163.41m^(3)/min,与空喷相比,风口风量更大;风口直径分别为110mm、115mm、120mm时,风口直径每扩大5mm,风量依次增加了5.81m/min、12.16m^(3)/min,与空喷相比,随着风口直径的增加,风量增加的趋势更加明显;风口插入深度分别为480500、520、560mm时,风量分别为159.61m^(3)/min、159.64m^(3)/min、159.69m^(3)/min、159.76m^(3)/min,与空喷相比,随着风口插入深度的增加,风量会增大,但增幅较小。

不同养殖模式对鲫鱼(Carassius auratus)营养品质及特征风味的影响研究

为研究池塘内循环流水养殖与传统池塘养殖模式条件下鲫鱼的营养品质及特征风味,对鲫鱼形体、基础营养成分、蒸煮损失和持水力、肌肉蛋白质消化率、氨基酸、脂肪酸和挥发性化合物含量等指标进行分析评价。结果表明:跑道组和池塘组鲫鱼的形体指标和基础营养成分具有较大差异,其中跑道组具有高蛋白低脂肪的特点。同时两种养殖模式下鲫鱼的蒸煮损失和持水力相接近。跑道组鲫鱼蛋白质消化率显著高于池塘组鲫鱼(P<0.05)。游离氨基酸分析结果表明跑道组鲫鱼中鲜味氨基酸(天冬氨酸和谷氨酸)和甜味氨基酸(谷氨酸和丙氨酸等)含量均显著高于池塘组(P<0.05),因此跑道组鲫鱼可能具有更佳的风味。此外两种养殖模式下鲫鱼肌肉氨基酸组成无显著差异(P<0.05),然而跑道组鲫鱼不饱和脂肪酸含量(4.8038 g/100 g)高于池塘组(1.4111 g/100 g)。基于GC-IMS结果可知,两种养殖模式下鲫鱼的挥发性化合物具有显著差异。通过层次聚类热图分析从57种挥发性化合物中筛选出了33种特性差异标记物用以区分不同养殖模式下的鲫鱼。研究结果表明,池塘内循环流水跑道养殖在一定程度上对鲫鱼营养品质和特征风味有所改善,可以通过GC-IMS技术进行有效快速鉴别,同时阐明了风味感官差异的物质基础,为淡水鱼养殖模式选择和产品定位提供理论基础。

轴承内圈沟道磨削热应力场有限元仿真分析

针对轴承套圈滚道磨削加工时过大的热应力会导致滚道表层产生热损伤的问题,联合ABAQUS及Hyper-Mesh建立B7008C角接触球轴承内圈沟道磨削热应力场有限元模型,开发DFLUX子程序减少模型分析步的数量,克服了网格数量庞大导致磨削热源无法沿沟道整周移动的问题,揭示了内圈沟道磨削热应力场的形成机制与演化规律,得到了内圈沟道表层产生残余拉应力的临界温度,并分析了工艺参数对内圈沟道残余拉应力分布的影响,结果表明:只有当磨削热应力超过材料的屈服强度时,内圈沟道表层才会产生残余拉应力,产生残余拉应力的临界温度约为420℃;随着热流密度的增大及工件转速的减小,内圈沟道表层的残余拉应力和分布深度增大。

Surface Roughness and Roundness of Bearing Raceway Machined by Floating Abrasive Polishing and Their Effects on Bearing's Running Noise

As the two most important indexes of bearing raceway, surface roughness and roundness have significant influence on bearing noise. Some researchers have carried out studies in this field, however, reason and extent of the influence of raceway surface geometric characteristics on bearing running noise are not perfectly clear up to now. In this paper, the raceway of 6309 type bearing＇s inner and outer ring is machined by floating abrasive polishing adopting soft abrasive pad. Surface roughness parameters, arithmetical mean deviation of the profile Ra, the point height of irregularities Rz, maximum height of the profile Rmax and roundness fof raceways, are measured before and after machining, and the change rules of the measured results are studied. The study results show that the floating abrasive polishing can reduce the surface geometric errors of bearing raceway evidently. The roundness error is reduced by 25%, Rm^x value is reduced by 35.5%, Rz value is reduced by 22% and Ra value is reduced by 5%. By analyzing the change of the geometrical parameters and the shape difference of the raceway before and after machining, it is found that the floating abrasive polishing method can affect the roundness error mainly by modifying the local deviation of the raceway＇s surface profile. Bearings with different raceway surface geometrical parameter value are assembled and the running noise is tested. The test results show that Ra has a little, Rmax and Rz have a measurable, and the roundness error has a significant influence on the running noise. From the viewpoint of controlling bearings＇ running noise, raceway roundness error should be strictly controlled, and for the surface roughness parameters, R,n^x and Rz should be mainly controlled. This paper proposes an effective method to obtain the low noise bearing by machining the raceway with floating abrasive polishing after super finishing.

Radiant Image Simulation of Pulverized Coal Combustion in Blast Furnace Raceway

The relationship between two-dimensional radiant image and three-dimensional radiant energy in blast furnace raceway was studied by numerical simulation of combustion process. Taking radiant image as radiant boundary for numerical simulation of combustion process, the uneven radiation parameter can be calculated. A method to examine three-dimensional temperature distribution in blast furnace raceway was put forward by radiant image processing. The numeral temperature field matching the real combustion can be obtained by proposed numeric image processing technique.

Flame radiant image numeralization for pulverized coal combustion in BF raceway

In order to establish correlativity between pulverized coal combustion in a blast furnace raceway and its radiant image, we investigated the relationships between two dimensional radiant images and three dimensional radiant energy in a blast furnace raceway, focusing on the correlativity of the numerical simulation of combustion processes with the connection of radiant images information and space temperature distribution. We calculated the uneven radiate characteristic parameterby taking radiant images as a kind of radiative boundary for numerical simulation of combustion processes, and put forward a method to examine three-dimensional temperatures distribution in blast furnace raceway by radiant image processing. The numeral temperature fields matching the real combustion can be got by the numeric image processing technique.

Regulation of water quality and growth characteristics of indoor raceway culture of Litopenaeus vannamei

Two modes of regulating the water quality of experimental ponds in indoor raceway culture of Litopenaeus vannamei were evaluated using simple water treatment facilities.A self-made water purifying net,aeration stone,composite microbe preparation,and Ceratophyllum demersum were placed in the experimental ponds and the culture water was circulated along the raceway inside the pond using a paddle wheel aerator.In addition,the water quality in the experimental pond was improved by draining effluent from the pipeline at the bottom of ponds 7 and 8 (mode I) and exchanging the circulating water in pond 10 (mode II) with the reservoir water in pond 9 using a pump and pipeline.The water quality in the experimental ponds was similar in response to regulation using mode I or mode II.Water quality parameters in the experimental ponds were controlled within a suitable range by simple facilities during culture period without using any chemical treatments.The rich content of dissolved oxygen was maintained by the circular flow and continuous aeration of the pond water.The respective average values of the main water parameters in experimental ponds 7 and 10 in response to regulation of the water quality using modes I and II were as follows:pH 8.17 and 7.99;DO 5.16 mg/L and 5.97 mg/L;CODMn 18.45 and 12.61 mg/L;TAN (NH3-N) 0.854 mg/L (0.087 mg/L) and 0.427 mg/L (0.012 mg/L);NO2-N 0.489 mg/L and 0.337 mg/L.Moreover,the average body length and body weight of harvested shrimp of pond 7 and pond 10 were 7.56 cm and 8.99 cm,5.10 g and 8.33 g,respectively.Furthermore,the survival rate,average biomass yield and average condition factor of the shrimp harvested were 70% and 60%,2.54 kg/m2 and 2.14 kg/m2,and 0.675 g/cm and 0.927 g/cm,respectively.Linear equations describing the relationship between body length and culture time and cubic or power functions describing the relationship between body weight and body length were obtained based on evaluation of the growth data of shrimps throughout the culture period.

Culturing of Autoflocculating Microalgal Consortium in Continuous Raceway Pond Reactor

The goal of this study was to develop a self-settling microalgal consortium in raceway pond reactor (RPR). Experiments were carried out with cultures that developed without additional seeding, but naturally promoted by process conditions in a raceway pond reactor. The changes in microalgal communities and total biomass under nitrogen and phosphorous limitations were studied in both batch and continuous systems. At the steady state batch had the population of 46% Euglena sp., 16% Closterium sp., 14% Chlorella sp., 14% Scenedesmus sp. and 10% Ankistrodesmus sp. with a maximum biomass of 900 mg/L. In order to get self-settling microalgal consortium, the operation was changed to continuous continuous mode with the aid of a specially designed settler for daily harvest and recycling of the biomass. Grazing fauna could be controlled by managing reduced liquid and solid retention time. At steady-state condition, an autofloculating and self-settling consortium was developed which had mainly Fragilaria sp., Scenedesmus sp., and filamentous Ulothrix sp. The maximum biomass concentration obtained was 140 mg/L. The presence of neutral lipid droplets in the consortium was identified by staining with Nile Red. Development of the lipid rich consortium could be a suitable method for producing biofuel.

A Novel Splash Plate Design for Serial Reuse Raceways

Serial reuse raceways in fish hatcheries typically use dam boards and screens to separate each raceway unit in the series. This paper describes a novel raceway splash plate constructed of aluminum plate and angle, which eliminates the need for screens when mounted on top of raceway dam boards. In addition to reducing the labor required to remove and replace, and clean screens, the splash plate increased the amount of available rearing space. Incoming water dissolved oxygen concentrations were also increased. These splash plates are relatively easy and inexpensive to fabricate, and their use can lead to increased efficiencies during hatchery rearing.

Optimization of Raceway Parameters in Iron Making Blast Furnace for Maximizing the Pulverized Coal Injection (PCI) Rate

This paper presents a method by which the maximum possible rate of pulverized coal injection (PCI) in blast furnace can be predicted. The method is based on a two-step approach. First, a first principle simulation model of the blast furnace is used to generate data sets for the development of a linear model of pulverized coal injection rate. The data has been generated randomly in MATLAB software within the range of operating parameters (constraints) of the blast furnace. After that, the coefficients of the function have been determined. The inputs and the resulting outputs formed the data on which the linear optimization model was developed. Next, the linear model was used for maximizing the pulverized coal rate injection by optimizing the other variables. Two operating Indian Blast Furnaces have been chosen to validate the optimization model.

流水槽养殖与传统池塘养殖的罗非鱼肌肉差异蛋白组学分析

目的利用蛋白组学技术对流水槽养殖与传统池塘养殖的罗非鱼肌肉的差异蛋白进行分析,探讨两种养殖模式罗非鱼肉质差异的分子机制。方法采用纳米液相色谱-串联质谱(Nano liquid chromatography-tandem mass spectrometry,Nano LC-MS/MS)技术手段,鉴定两种养殖模式罗非鱼鱼肉差异蛋白,并进行代谢通路的分析。结果在两种鱼肉中共鉴定到蛋白3684个,其中共检测到差异表达的蛋白为26个。与传统池塘养殖的鱼肉相比,流水槽养殖的鱼肉中磷酸化酶b激酶、硫氧还蛋白还原酶、腺苷酸琥珀酸酶、蛋白酶体抑制剂等蛋白的表达量显著提高;而胞质脂肪酸结合蛋白1/2、Ⅻ型胶原蛋白、线粒体导肽水解酶β等表达量则显著降低。这些差异蛋白与机体内蛋白质、脂肪的累积紧密相关,这可能也是本研究中观察到流水槽养殖罗非鱼鱼肉具有高蛋白、低脂肪的原因之一。生物学功能显示差异蛋白主要分布在转运活性方面,而差异蛋白功能通路的富集结果表明大多数差异蛋白与心肌的收缩、甲状腺激素合成、丙氨酸/天冬氨酸/谷氨酸代谢、细胞内吞作用有关。结论本研究得出的差异蛋白和关键代谢通路与鱼肉中蛋白质、脂肪含量密切相关,为阐明流水槽养殖模式下罗非鱼肉品质的形成机制奠定了基础,为后续贮藏、加工方法选择提供依据。

放养密度对IPRA养殖太湖鲂鲌生长、抗氧化酶及肠道微生物群落的影响

为探讨池塘内循环流水养殖(In-pond Raceway Aquaculture,IPRA)太湖鲂鲌幼鱼的合理放养密度,以初始体重为(5.58±0.45)g的太湖鲂鲌幼鱼为研究对象,设置3个放养密度:0.5(SD1)、1.0(SD2)、1.5 kg/m^(3)(SD3),在养殖第90、第120、第150、第180天采样,对其生长性能、血清和肝脏抗氧化酶活力进行分析,实验结束后分析肠道微生物群落组成。生长结果表明:养殖120d,当放养密度超过1.0 kg/m^(3)时,太湖鲂鲌幼鱼的体重和特定生长率(SGR)显著降低(P<0.05),养殖150—180d,体重和SGR随着放养密度的升高显著降低(P<0.05)。血清抗氧化酶结果表明:养殖90d,太湖鲂鲌血清抗氧化酶的活力随着放养密度的升高而增加,SD3组显著高于SD1组(P<0.05)。养殖150—180d,血清抗氧化酶的活力随着放养密度的升高而降低,养殖180d,SD3组抗氧化酶的活力显著低于SD1组(P<0.05)。肝脏抗氧化酶结果表明:养殖150—180d,肝脏中抗氧化酶活力随着放养密度的增加而升高,GSH-Px的活力随着放养密度的增加显著升高(P<0.05)。养殖前120d,丙二醛(MDA)的水平随着放养密度的升高有所降低,养殖180d,SD2和SD3组的MDA水平显著高于SD1组(P<0.05)。肠道微生物结果表明,在属水平,各密度组肠道微生物群落组成发生明显改变,气单胞菌属(Aeromonas)、假单胞菌属(Pseudomonas)和不动杆菌属(Acinetobacter)等在SD3组的相对丰度显著增加(P<0.05),而Shannon多样性指数显著降低(P<0.05)。综上,在试验条件下,当养殖时间小于120d,放养密度小于1.0 kg/m^(3)时,太湖鲂鲌幼鱼的生长和抗氧化能力未受显著影响,建议放养密度小于1.0 kg/m^(3);当养殖时间为150—180d,放养密度大于0.5 kg/m^(3)时,放养密度对太湖鲂鲌幼鱼的生长产生了抑制,肠道微生物群落组成中条件致病菌显著增加、多样性指数显著降低,建议放养密度小于0.5 kg/m^(3)。

实现高等教育“高质量发展”的着力点--质量理念更新与共同体重构

新时期我国高等教育的“高质量发展”,不仅意味着“质量提升”取代“数量增长”成为首要目标,也不仅仅是更突显了追求卓越、创建一流的意涵,还具有了面向未来,重构大学人才培养理念、教学范式、课程体系与专业形态的“质”的飞跃。中国的大学应当改弦更张,面对社会需求的变化和科学技术的挑战,尽快地切入新的赛道。这"新的赛道"主要体现在两个“深度融合”,即多学科交叉与深度融合,以及大学与社会的深度融合,通过产教融合、科教融汇来满足社会发展对大学人才培养与智力支撑的需求。质量理念的转换与思想解放,以及大学运行与发展所依赖的"共同体"的拓展与重构,是实现高等教育“高质量发展”的两个主要切入点和着力点。

Numerical Research of the Influences of the Outer Raceway Curvature Radii on the EHL Properties of Ball Bearing

Based on numerical simulation, the influences of outer raceway curvature radii on some EHL properties of deep groove ball bearing were studied in detail. It was found that the second peak film pressure value decreases with the increase of curvature radius Ry. The minimal film thickness increases at first and then decreases with the increase of curvature radius Ry. The minimum film thickness reaches the maximal value when curvature radius Ry is about 1.7r. Film thickness becomes thinner with the increase of Rx with keeping other parameters constant. The conclusions obtained in this paper are very helpful to practical design of ball bearings.

考虑外滚道缺陷的滚动轴承刚度时变特性分析

滚动轴承的主要失效形式之一是在滚道或滚动体表面产生缺陷,形成疲劳点蚀,对轴承性能产生很大影响。针对深沟球轴承,建立外滚道存在方形缺陷时的动力学模型,获取缺陷对载荷分布的影响规律,建立轴承时变刚度模型,分析缺陷尺寸演化和位置对轴承刚度时变特性的影响规律。结果表明:当缺陷位于非承载区时对轴承平均刚度无影响;当缺陷位于承载区时,轴承的平均刚度与缺陷长度和深度负相关;缺陷位置由底端向非承载区变化时,轴承的平均刚度先减小后增大。

滚珠丝杠精密磨削表面加工质量及其试验研究

通过正交试验设计和单因素分析法对滚珠丝杠滚道磨削工艺开展了试验研究,分析了磨削时砂轮粒度、砂轮速度、丝杠速度以及磨削深度对滚珠丝杠表面质量影响的主次顺序,得出了各工艺参数对表面质量的影响规律,为丝杠和螺母磨削工艺参数的选择提供了依据。另外试验研究了滚道表面质量对滚珠丝杠副摩擦力矩和噪声性能的影响,明确了滚道表面粗糙度和摩擦力矩之间的关系。试验结果表明,提高丝杠滚道表面加工质量能够有效降低滚珠丝杠副摩擦力矩和噪声。