多风井混合式通风矿井反风演习实践

为探究全矿反风风速对硐室火灾烟气蔓延的影响,利用FDS火灾数值模拟软件构建矿井巷道三维模型,模拟全矿反风风速为1.0、1.5、2.0、2.5 m/s条件下的火灾场景,分析不同反风风速下硐室左右两侧烟气浓度和巷道内能见度的变化情况。研究结果表明：当全矿反风风速为1.0 m/s时,巷道进风侧风流紊乱,烟气出现明显回流现象;随着反风风速的增大,进风侧风流方向开始反转,巷道内能见度和风流反向速率不断增大;反风风速为1.5~2.0 m/s较合适,且当针对硐室火灾事故采取救灾救援措施时,反风风速需确保大于临界风速2.5 m/s。

     

基于TMS320C6711的线阵CCD测量系统及其在煤泥水监测中的应用研究

本文介绍数字信号处理器DSP在线阵CCD信号实时采集与处理系统中的应用。研究了通过提取煤煤泥水图像的特征量,来测量煤泥水的浓度,并以此实时指导生产。     

一种谐振式密度（浓度）分析仪的研制与应用

矿浆浓度（密度）的测量一直是选矿行业的技术难题,对矿浆浓度（密度）的测量精度直接影响着选矿自动化的控制水平和控制效果。谐振式密度（浓度）分析仪是根据元器件振动衰减原理而设计,主要由音叉传感器、驱动检测电路、主控芯片、辅助电路和相应的壳体构成。浓度仪在工作时由激励线圈产生激励促使音叉体产生振动,振动频率由压电晶体检测出来,并通过移相和放大电路后转换为测量所需的电信号。当液体流经振动叉体时,因流体质量的改变引起谐振频率的变化,仪器采集系统采集这些频率变化。由于不同密度的流体流经振动系统时会产生不同的振动频率,仪器检测出振动频率变化后即可通过振动频率与密度间的函数关系式计算出流经流体的密度值,推算流经流体的浓度值。谐振式密度（浓度）分析仪在南京某选厂应用结果表明,该设备可以提高选矿过程浓度检测的准确性和可靠性。     

Determination of Critical Aggregation Concentration in the Poly-(vinylpyrrolidone)–Sodium Dodecyl Sulfate System by Capillary Electrophoresis

We introduce an alternative separation method, i.e., capillary electrophoresis to examine the polymer/surfactant interaction. The migration behavior of the poly-(vinylpyrrolidone)–sodium dodecyl sulfate (PVP–SDS) model system was screened under a high electrical field for seven different PVP initial concentrations. From the electrophoretic mobilities of formed polymer–surfactant species, the critical aggregation concentration (CAC) of SDS for PVP was determined. The CAC value in the present study was very well matched with the CAC values of this system reported by alternative methods. A strong interaction between polymer and SDS under CAC concentration was observed and the independence of CAC on polymer concentration was experimentally demonstrated.     

EFFECT OF GEOMETRIC PARAMETERS ON VENTILATION PERFORMANCE IN A DRY ROOM

ABSTRACT

The characteristics of moisture ventilation in a dry room are studied numerically. The effects of three important parameters: the positions of outlets, the aspect ratio (β) of horizontal section and the air exchange rate (N), are analyzed in terms of the scales of ventilation efficiency. Ventilation performance is evaluated by varying the aspect ratio and the air exchange rate for the four different outlet arrangements. It is found that the ventilation performance is improved when the aspect ratio in the transverse arrangement of outlets is decreased. Ventilation efficiency reaches its highest value when β is set to be 4 in the longitudinal arrangement of outlets. Regardless of the aspect ratio, the upper arrangement of the outlets shows a better ventilation performance than the lower arrangement. For all geometrical models and aspect ratios investigated in this study, the increase of the air exchange rate for improving the ventilation performance is only valid up to 60 h^?1.     

A generalised back-flow model to predict the tracer response in liquid—liquid stagewise contactors

A generalized transient back-flow model to predict the transient tracer concentration in a multistage extraction column has been developed. The model does not assume any extra stage at the end of the contactor and is based on unified formulation. The solution can be obtained in a straight forward way by using the linear operator theoretic approach as opposed to Laplace transform.     

生物传感器法检测葡萄汁中葡萄糖含量

采用葡萄糖氧化酶与过氧化氢电极,在0.2 mol/L的磷酸盐缓冲液（pH 7.2）和1‰的葡萄糖标准溶液反应体系中,建立葡萄汁中葡萄糖含量检测的生物传感器分析方法。结果表明,在葡萄糖质量浓度为0～1 000 mg/L的范围内生物传感器法测定葡萄糖含量的线性良好;线性回归方程为y=0.994 8x-3.081,相关系数R2=0.999 9;稳定性好,相对标准偏差（RSD）=1.63%;加标回收率为96.0%～102.4%;专一性强,只对葡萄糖进行专一性测定。     

重组戊型肝炎疫苗抗原工程菌发酵工艺的优化

目的优化重组戊型肝炎疫苗抗原工程菌的发酵工艺,为其规模化生产奠定基础。方法以目的蛋白的表达量及菌体浓度作为综合评价指标,对重组戊型肝炎疫苗抗原工程菌的摇瓶发酵温度、初始pH值、溶解氧、IPTG浓度及诱导时间进行优化;以摇瓶发酵结果为基础,进一步对发酵罐培养工艺中诱导时机、诱导时间及补料培养基配方进行优化;以确定的罐发酵工艺条件连续发酵5批,验证该发酵工艺。结果最适摇瓶发酵工艺条件为:发酵温度为37℃,初始pH值为7.0,高溶氧,IPTG诱导浓度为0.05 mmol/L,诱导时间为4 h;最适罐发酵工艺条件为:菌体A600值约为40时开始诱导,诱导时间为4 h,补料培养基配方为葡萄糖25%,MgSO4.7H2O 0.5%。按照确定的工艺连续发酵5批,最终菌体A600均达50.0以上,目的蛋白的表达量均高于15%。结论优化的重组戊型肝炎疫苗抗原工程菌的发酵工艺稳定性良好,已达到中试生产规模的要求。     

Behavior of bridge girders with corrugated webs under monotonic and cyclic loading

The focus of this study is to investigate the behavior of plate girders with trapezoidally corrugated webs under fatigue loading. Six girders were tested under both monotonic and cyclic four-point loading arrangements. A relationship between the stress range, F_r, and the number of cycles to failure, N, was developed for the girders. The results from the fatigue tests were related to the current AASHTO specifications and compared with the test results of different types of girders carried out by others. Nonlinear finite element analyses were conducted to study the effects of the different geometrical parameters of this type of girders on the stress concentrations at different locations and to explain the findings of the experimental study. Two sources of stress concentration leading to fatigue cracking were isolated and evaluated; one is dependent on the radius of curvature between the web folds and the other depends on the inclination angle of the inclined fold. An analytical technique based on fracture mechanics is also proposed to enable designers to determine the fatigue life of corrugated web steel girders.     

Kinetics of emitted mass—A study with three dry powder inhaler devices

The purpose of this study was to understand the kinetics of emptying of micronised salbutamol sulphate (SS) and lactohale 300 (LH300) under varying air flow rates (30–180 L min⁻¹) from three dry powder inhaler devices, Rotahaler^® (RH), Monodose Inhaler^® (MI) and Handihaler^® (HH). Aerosol concentration vs. time profiles, determined through real-time laser diffraction particle sizing, demonstrated that the majority of the powder from RH was emitted within one second while a more prolonged aerosolisation was observed from MI and HH. Peak aerosol concentrations were achieved more rapidly from RH compared to MI for both SS and LH300. Calculated cumulative emitted mass (CCEM) vs. time profiles were obtained from the aerosol concentration vs. time profiles and the emitted mass and the rate of CCEM (k_CCEM), estimated from a modelling approach, increased with increasing air flow rates. The k_CCEMvs. air flow rate profiles of SS and LH300 were significantly different at high air flow rates. The k_CCEM was highest from RH and lowest from MI. Differences in k_CCEM between the devices were related to capsule aperture size while the differences between the materials were due to the powder bed structure. This approach provided an understanding of the rate at which powder mass emptied from dry powder inhaler devices and was proposed to be a powerful development tool for the future powder inhalers.