Influence of coke rate on thermal treatment of waste selective catalytic reduction (SCR) catalyst during iron ore sintering

Waste selective catalytic reduction (SCR) catalyst as a hazardous waste has a significant impact on the environment and human health. In present study, a novel technology for thermal treatment of waste SCR catalyst was proposed by adding it to sinter mix for iron ore sintering. The influences of coke rate on the flame front propagation, sinter microstructure, and sinter quality during sintering co-processing the waste SCR catalyst process were studied. In situ tests results indicated the maximum sintering bed temperature increased at higher coke rate, indicating more liquid phase generated and higher airflow resistance. The sintering time was longer and the calculated flame front speed dropped at higher coke rate. Sinter microstructure results found the coalescence and reshaping of bubbles were more fully with increasing coke rate. The porosity dropped from 35.28% to 25.66%, the pore average diameter of large pores decreased from 383.76 μm to 311.43 μm. With increasing coke rate, the sinter indexes of tumbler index, productivity, and yield, increased from 33.2%, 9.2 t·m^-2·d^-1, 28.9% to 58.0%, 36.0 t·m^-2·d^-1, 68.9%, respectively. Finally, a comprehensive index was introduced to systematically assess the influence of coke rate on sinter quality, which rose from 100 to 200 when coke rate was increased from 3.5% (mass) to 5.5% (mass).     

静电单透镜在低能强流离子束输运中的应用

本文介绍北京大学重离子所RFQ组利用静电单透镜进行低能强流离子束束流输运的情况.在北京大学1 MeV ISR RFQ加速器的升级改造中,我们在低能输运段使用了2个静电单透镜进行调束,当引出电压为22kV时,在RPQ入口处得到了归一化均方根发射度为0.12 7× mm·mrad、峰值流强6 mA的脉冲氧离子束(相当于24mA质子束流).以及用静电单透镜聚焦强流氢离子束的初步实验实验.     

Abnormal Acoustic Event Detection Based on Orthogonal Matching Pursuit in Security Surveillance System

Wireless Personal Communications - This paper presents a feature extraction approach for surveillance system aimed at achieving the automatic detection and recognition of public security events....     

PKUNIFTY: A neutron imaging facility based on an RFQ accelerator

A neutron imaging facility, PKUNIFTY, based on a radio frequency quadrupole (RFQ) accelerator-driven compact neutron source, presently under construction at the Peking University, is described. It consists of a deuteron linear accelerator, a neutron target-moderator-reflector assembly, and a thermal neutron imaging system. Neutrons are generated via the deuteron-beryllium reaction with an expected fast-neutron yield of 3×10¹² n/s. The thermal neutron flux on the imaging plane is 5×10⁵ n/cm²/s at a nominal L/D ratio of 50, and the L/D ratio can be selectable over a range of 25-200. The corresponding n/γ ratio is close to or higher than 1×10¹⁰ n/cm²/Sv. The field of view is 20 cm×20 cm at 2 m downstream of the collimator entrance aperture where the thermal neutron flux uniformity is better than 7%. The effective Cd ratio can be tuned by using a light chopper and neutron time-of-flight technique without excessive sacrifice of the thermal neutron flux.     

煤巷综掘工作面喷雾除尘自动控制系统

针对煤巷工作面粉尘治理的问题,设计煤巷高压喷雾除尘自动控制系统。粉尘传感器及时监测工作面煤矿粉尘浓度,设置上限、下限两个动作阈值,采用PIC16F877处理器控制电磁阀打开和关断高压供水管路喷雾装置,并可通过热释电红外传感器检测人体信号,在矿工通过喷雾区域时暂时停止喷雾。该系统实现喷雾过程自动控制,高压喷雾装置有效地降低了工作面粉尘浓度,提高了除尘效率,改善了矿工工作环境。     

陶瓷刀具高速铣削4Cr13不锈钢铣削力试验研究

采用单因素试验,分析了切削速度vc、每齿进给量fz和切削深度ap对铣削力的影响规律,结果表明:随着切削速度vc的增大,铣削力减少;随着每齿进给量fz和切削深度ap增大,铣削力增大。同时,设计了4Cr13不锈钢正交试验方案,基于概率统计和回归分析原理,建立了4Cr13不锈钢高速铣削的铣削力模型,对建立的铣削力模型进行了显著性检验,检验结果表明所建立的回归方程呈高度显著检验状态,并对其进行了验证,结果表明该模型与实际情况拟合得较好,故可用其来预测和控制铣削力。     

TC4钛合金铣削刀具C形刃几何参数优化实验研究

通过对TC4钛合金进行侧铣加工,采用正交设计方法研究了硬质合金立铣刀侧刃几何参数对切削力和表面粗糙度的影响,用极差法分析了刀具几何参数对铣削力的影响;并以最小表面粗糙度为目标,采用田口法对刀具几何参数进行了优选。结果表明:螺旋角对铣削力的影响最大,对F_x、F_z,C形刃宽度影响次之,C形刃角度的影响最小;对于F_y,C形刃角度次之,C形刃宽度的影响最小;当螺旋角为25°、C形刃宽度为0.2mm、角度为-25°时可获得最小表面粗糙度。     

一种超声超低温冰层支撑辅助CFRP钻削方法

提出一种超声振动+超低温液氮+由超低温环境形成的冰冻支撑层(Ultrasonic vibration+Cryogenic liquid nitrogen+Frozen support layer,UCF)来辅助碳纤维增强树脂基复合材料(Carbon fiber reinforced poly-mer,CFRP)钻削制孔...     

强流RFQ加速器注入器的研究进展

用于中子照相的2MeVRFQ加速器须注入50 mA@50keV的脉冲D+离子束,束流占空比为1/10,发射度0.2 π-mm-mrad.а=1.93,β=5.16cm/rad.为此,我们建立了两台基于2,415 GHz的永磁微波离子源实验台.当微波功率小于450 w时,引出氢离子流的总流强大于80 mA,质子比好于90%,束流的归一化均方根发射度约为0.2-0.3π-mm-mrad.LEBT(低能束流输运线)实验台使用-个半包围结构螺线管磁透镜,束流传输效率大于80%.为优化源体设计,对源室尺度和放电室内衬材料研究,为源体的优化提供了依据.     

基于Web的CNC机床远程故障诊断系统

对基于Web的Multi-agent 的远程故障诊断技术进行了研究,提出基于知识的Multi-agent的数控机床(CNC)的远程故障诊断系统,该系统由诊断和学习agents(DLA)、远程设备agents(RMA)和中央管理agent(CMA)组成.通过这些Agents之间的协作和通信,实现CNC机床的远程监测和故障诊断.