Comparison of a Spectral Bin and Two Multi-Moment Bulk Microphysics Schemes for Supercell Simulation:Investigation into Key Processes Responsible for Hydrometeor Distributions and Precipitation

There are more uncertainties with ice hydrometeor representations and related processes than liquid hydrometeors within microphysics parameterization(MP)schemes because of their complicated geometries and physical properties.Idealized supercell simulations are produced using the WRF model coupled with“full”Hebrew University spectral bin MP(HU-SBM),and NSSL and Thompson bulk MP(BMP)schemes.HU-SBM downdrafts are typically weaker than those of the NSSL and Thompson simulations,accompanied by less rain evaporation.HU-SBM produces more cloud ice(plates),graupel,and hail than the BMPs,yet precipitates less at the surface.The limiting mass bins(and subsequently,particle size)of rimed ice in HU-SBM and slower rimed ice fall speeds lead to smaller melting-level net rimed ice fluxes than those of the BMPs.Aggregation from plates in HU-SBM,together with snow–graupel collisions,leads to a greater snow contribution to rain than those of the BMPs.Replacing HU-SBM’s fall speeds using the formulations of the BMPs after aggregating the discrete bin values to mass mixing ratios and total number concentrations increases net rain and rimed ice fluxes.Still,they are smaller in magnitude than bulk rain,NSSL hail,and Thompson graupel net fluxes near the surface.Conversely,the melting-layer net rimed ice fluxes are reduced when the fall speeds for the NSSL and Thompson simulations are calculated using HU-SBM fall speed formulations after discretizing the bulk particle size distributions(PSDs)into spectral bins.The results highlight precipitation sensitivity to storm dynamics,fall speed,hydrometeor evolution governed by process rates,and MP PSD design.

Study on Limited Filamentous Sludge Bulking Test in A/O Activated Sludge Process

[Objective] This study aimed to make use of the limited filamentous sludge bulking characteristics to purify water quality and save energy. [Method] The effects of dissolved oxygen （DO） on sludge bulking were explored by changing the DO con- centration in the aerobiotic pool of NO system from the low load （0.25 kg COD/（kg MLSS.d）） and the medium to high load （0.55 kgCOD/（kg MLSSod））. [Result] In the NO activated sludge system, when the sludge load was 0.25 kg COD/（kg MLSS.d）, DO=1.5 mg/L, the sludge index was at around 250, while when the sludge load- ing was 0.55 kg COD/（kg MLSS.d）, DO=1.5 mg/L, the sludge index was close to 300, occurring the limited filamentous bulking. The bulked sludge still showed high removal rates to COD, SS, nitrogen and phosphorus. [Conclusion] It could improve the oxygen transfer rate and reduce the aeration rate at low DO conditions to achieve energy-saving.

Effect of supply voltage and body-biasing on single-event transient pulse quenching in bulk fin field-effect-transistor process

Charge sharing is becoming an important topic as the feature size scales down in fin field-effect-transistor （FinFET） technology. However, the studies of charge sharing induced single-event transient （SET） pulse quenching with bulk FinFET are reported seldomly. Using three-dimensional technology computer aided design （3DTCAD） mixed-mode simulations, the effects of supply voltage and body-biasing on SET pulse quenching are investigated for the first time in bulk FinFET process. Research results indicate that due to an enhanced charge sharing effect, the propagating SET pulse width decreases with reducing supply voltage. Moreover, compared with reverse body-biasing （RBB）, the circuit with forward body-biasing （FBB） is vulnerable to charge sharing and can effectively mitigate the propagating SET pulse width up to 53% at least. This can provide guidance for radiation-hardened bulk FinFET technology especially in low power and high performance applications.

Three-Dimensional Rigid-Plastic FEM Simulation of Bulk Forming Processes with New Contact and Remeshing Techniques

Some techniques such as die surface description, contact judgement algorithm and remeshing are proposed to improve the robustness of the numerical solution. Based on these techniques, a three-dimensional rigid-plastic FEM code has been developed. Isothermal forging process of a cylindrical housing has been simulated. The simulation results show that the given techniques and the FEM code are reasonable and feasible for three-dimensional bulk forming processes.

Comparison of Y₂Ba₄CuBiOy Nanoparticles with CeO₂Doping on the Levitation Force of Single Domain YBCO Bulk Superconductor by TSIG Process

The top-seeded infiltration and growth process (TSIG) is very effective method for the preparation of YBa2Cu3O7-x (YBCO) bulk superconductors. In order to improve the levitation force of the samples, a series of single domain YBCO bulk superconductors with different ratios of nanoscale Y2Ba4CuBiOy (YBi2411) inclusions in the solid phase pellet is successfully fabricated by the TSIG technique on the basis of previous research. In the present work, the results of YBCO bulk superconductors with YBi2411 and CeO2 (1 wt%) codoping system indicate that, the optimum doping of YBi2411 is 2 wt%, the size of Y211 particles is reduced compared with the samples without CeO2 doping;the largest levitation force is about 15 N obtained in the samples with optimum YBi2411, which is about two times higher than that of the sample without CeO2 doping. The results are very helpful for the fabrication of high quality single domain YBCO bulk superconductors.

Application of semisolid process to Zr-based metallic glass matrix composites

The effect of the cooling slope on the structure of Zr-based metallic glass matrix composites was investigated by changing the cooling slope.The synthesis of bulk metallic glass composites was made by a process combining cooling slope casting and Cu mold casting for Zr66.4Nb6.4Cu10.5Ni8.7Al8 alloys.The results show that the semisolid slurry which consists of the spheroidal or rosette-type BCC crystals and the liquid phase which forms metallic glass phase can be formed by the cooling slope process in this alloy system.However,the semisolid slurry cannot reach to the mold.It is considered that higher viscosity of the liquid phase which forms metallic glass phase causes this result.Thus,parameters of the cooling slope have to be examined further.

Activation of 2D MoS_(2) electrodes induced by high-rate lithiation processes

MoS_(2) is a highly promising material for application in lithium-ion battery anodes due to its high theoretical capacity and low cost.However,problems with a fast capacity decay over cycling,especially at the first cycles,and poor rate performance have deterred its practical implementation.Herein,electrodes comprised solely of few-layers 2D MoS_(2) nanosheets have been manufactured by scalable liquid-phase exfoliation and spray deposition methods.The long-standing controversy questioning the reversibility of conversion processes of MoS_(2)-based electrodes was addressed.Raman studies revealed that,in 2D MoS_(2) electrodes,conversion processes are indeed reversible,where nanostructure played a key role.Cycling of the electrodes at high current rates revealed an intriguing phenomenon consisting of a continuously increasing capacity after ca.100-200 cycles.This phenomenon was comprehensively addressed by a variety of electrochemical and microscopy methods that revealed underlying physical activation mechanisms that involved a range of profound electrode structural changes.Activation mechanisms delivered a capacitive electrode of a superior rate performance and cycling stability,as compared to the corresponding pristine electrodes,and to MoS_(2) electrodes previously reported.Herein,we have devised a methodology to overcome the problem of cycling stability of 2D MoS_(2) electrodes.Moreover,activation of electrodes constitutes a methodology that could be applied to enhance the energy storage performance of electrodes based on other 2D nanomaterials,or combinations thereof,strategically combining chemistries to engineer electrodes of superior energy storage properties.

城市污水处理过程污泥膨胀识别与抑制综述

污泥膨胀是活性污泥法污水处理过程中常见的一类异常工况,且具有严重危害性,研究污泥膨胀的识别和抑制方法对城市污水处理过程正常运行意义重大.本文主要针对城市污水处理过程中污泥膨胀的识别和抑制方法进行综述.首先,文章概述了城市污水处理过程,介绍了污泥膨胀的概念、主要特点、类型和成因;其次,概述了基于微生物生理特征、机理模型、图像识别和数据驱动的污泥膨胀识别方法,分析其发展现状并指出优缺点;然后,概述了基于过程调控和机理特征的污泥膨胀抑制方法,分析其发展现状并对比优缺点;最后,总结全文,指出了城市污水处理过程污泥膨胀识别和抑制面临的主要问题,并对其研究趋势进行了展望.

云南某细粒铜钼混合精矿分离工艺优化及工业应用

云南某细粒硫化铜钼混合精矿中主要有价金属元素为铜和钼,矿石中主要矿物为黄铜矿和辉钼矿,脉石矿物主要是石英和云母,铜、钼矿物嵌布粒度较细,与脉石矿物复杂共生。针对混合精矿分离难度大、分离指标较差、药剂单耗用量大、药剂成本高的现状,结合混合精矿含钼品位的上升,在工艺矿物学研究基础上,开展了选矿试验研究。通过对原有工艺及药剂制度进行优化试验,研制了新型铜钼分离药剂D117和D118,其中D117为铜抑制剂,D118为调整剂。在原矿铜品位20.75%、钼品位0.47%的条件下,采用“抑铜浮钼”、一次粗选、四次精选、一次扫选浮选工艺,获得钼品位45.15%、铜品位1.03%、钼作业回收率85.65%的钼精矿及含钼0.069%、铜品位20.92%、铜作业回收率99.96%的铜精矿,取得了良好的实验室选别指标。将研究成果应用于工业生产后,浮选浓度由18%提升至33%,系统台效由17.4 t/h提高至25.9 t/h,钼作业回收率由66.11%提升至80.55%,年产钼金属由286 t提高至710 t。同时,D117、D118新型小分子药剂的使用取消了水玻璃的添加,并大幅降低了硫化钠用量,硫化钠粗选用量由设计之初125000 g/t降至6000 g/t,降幅达95.20%。通过药剂制度的持续优化,进一步压缩了硫化钠用量,硫化钠单耗由13.4 kg/t降至7.53 kg/t,D117单耗由6.18 kg/t降至3.98 kg/t,在药剂成本大幅度降低的前提下,实现了铜钼分离系统处理量及生产指标的双提升。

白云鄂博稀土混合精矿工艺矿物学研究

目前白云鄂博稀土元素的提取主要采用重污染和高能耗的高温浓硫酸焙烧法,“三废”问题至今没有得到合理的解决,且钍元素作为一种伴生组分难以得到再回收利用。采用自动矿物分析仪、X射线衍射分析、扫描电镜分析、配分分析、光学显微镜等分析方法对白云鄂博稀土混合精矿的化学成分、矿物组成、粒度及嵌布特征等进行了工艺矿物学研究,结果表明,该稀土混合精矿REO品位为59.25%,主要稀土矿物由氟碳铈矿、独居石和氟碳钙铈矿组成,主要脉石矿物为磷灰石、萤石、黄铁矿和磁/赤铁矿。在矿物中主要分布的稀土元素为La、Ce、Pr、Nd、Sm、Gd。矿样中矿石-38μm粒级含量占95.92%,氟碳铈矿和独居石单体解离度均在55%以上,矿石整体嵌布特征较为复杂,稀土矿物与萤石和磷灰石的连生关系最为密切。为简化冶金工艺,高效提取稀土元素,提出了采用矿相转化后“浮少抑多”的方法分离氟碳铈矿和独居石的展望,为白云鄂博稀土混合精矿的合理开发应用提供新思路。

Fabrication and Growth Mechanism of Single-crystalline Rutile TiO_2 Nanowires by Liquid-phase Deposition Process in a Porous Alumina Template

TiO2 nanowire arrays were successfully fabricated by liquid-phase deposition method using porous alumina templates. The obtained TiO2 nanowires were characterized using Raman spectroscopy, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, field emission scanning electron microscopy （FE- SEM）, transmission electron microscopy （TEM）, and selected area electron diffraction （SAED） analysis. Results of electron microscopic observations indicated that the nanowires were smooth and uniform with a diameter of about 50-80 nm and several micrometers in length. SAED, Raman, and XRD mea- surements showed that TiO2 nanowires were single-crystalline with a pure rutile structure after heating at 800 ~C for 10 h. In this situation, the nanowire constituents grew preferentially along the 〈001〉 direction. Furthermore, the formation process and mechanistic study of the Ti02 nanowire arrays were proposed and discussed in detail. The nanowires are clearly produced by the deposition of TiO2 particles on the inner wall of the template nanochannels.

卧式捏合反应器及其在聚合工业中的研究进展

卧式捏合反应器具有大的反应体积,优异的混合性能、表面更新性能、传热性能和自清洁性能,因而在本体聚合、缩合聚合和聚合物脱挥等领域具有广阔的应用前景。综述了几种捏合反应器及其搅拌特性研究,以及在聚合工业中的应用研究,指出捏合反应器具有非常复杂的几何结构,实验测量技术具有很大的局限性,计算流体力学(CFD)模拟为主要的研究方法;进一步指出具有自清洁特性的捏合反应器是聚合物搅拌设备开发的主要方向,高效、集约化、绿色、环保的先进工艺与装置是促进我国聚合工业发展的关键。

散料仓储物流建筑优化策略研究——以满洲里钾肥厂房设计为例

仓储物流建筑在工农业生产中具有重要作用,在物流过程中承担短期储藏和初步加工的功能。然而,现阶段国内大部分仓储转运建筑还存在功能分区不合理、转运效率低等问题。为此,本文基于传统散料仓储转运流程,借鉴国内外先进口岸转运方式,以满洲里钾肥转运厂房设计为例,从转运流程、仓储空间、厂房形态三个层面提出散料仓储建筑设计优化方案,以期提高仓储转运效率、降低转运成本。

某散货船典型舷侧分段制作工艺

本文对某散货船典型舷侧分段制作工艺流程进行全面介绍,阐述分段划分、脚手架、扫砂等主要工艺流程,及分段DAP、焊接、精度、预密性等主要工艺方法,总结其分段制作工艺。

A^(2)O工艺活性污泥黏性膨胀原因及控制措施

污泥黏性膨胀问题一直是A^(2)O工艺运行控制的难点。郑州市某污水处理厂在运行过程中出现污泥黏性膨胀问题,造成污泥沉降性能变差,SVI逐渐提升至240 mL/g左右,二沉池泥位持续升高。从进水水质、水温、曝气量、浮渣等多方面综合分析引起污泥膨胀的原因,及时从剩余污泥排放量、污泥龄、溶解氧、回流比、水力停留时间等工艺参数调整运行工艺,使污泥膨胀问题得到一定程度的缓解。为彻底消除生物池浮泥,又通过在二沉池配水井精准投加40 mg/L的阳离子高分子絮凝剂,经过一段时间的药剂助沉,明显提高了污泥沉降性能,SVI也逐渐下降至120 mL/g左右的正常水平,解决了污泥黏性膨胀问题,消除了生物池浮泥,为解决污泥黏性膨胀提供了思路。

老厂改造汽运水泥散装车间工艺设计

介绍了老厂改造汽运水泥散装车间工艺设计过程,通过物流平衡计算,兼顾了水泥包装和水泥散装多功能需求,达到了提高散装水泥发运能力和发运效率的目的。

散货港口生产流程切换方式对比分析

在散货码头作业过程中,现场流程启停频繁,涉及到很多的流程切换。每一次流程启停都需要消耗大量的电能,并对设备造成一定的冲击。对比分析生产流程的传统流程切换方式和“热切换”方式,结果表明,生产流程“热切换”方式可减少设备启停频次、降低能耗、降低对设备的冲击。

散粮铁水联运过程装卸环节节粮减损的探讨

近年来,随着《粮食节约行动方案》的发布,做好节粮减损工作愈发重要。为实现粮食全产业链各环节减损,本文从装卸设备选型、作业减损通用要求、后续搭接设备要求及管理要求4个方面,提出散粮铁水联运中装卸环节节粮减损的建议,为散粮多式联运运输过程的节粮减损提供一定的参考,进而提高我国粮食安全保障水平。

基于物联网技术的智能散状物料带式输送系统的远程监控与管理研究

研究了基于物联网技术的智能散状物料带式输送系统的远程监控与管理,旨在实现对带式输送系统的远程监控和智能化管理,以提高效率和可靠性。为实现此目的,首先分析了物联网技术及其在带式输送系统中的潜在应用;其次设计了带式输送系统的物联网技术框架,进一步构建了远程监控与管理系统。研究结果显示,物联网技术在实现智能散状物料输送系统中具有高度的可行性和效率。最后讨论了实现过程中的关键技术和创新点,为该领域的进一步研究提供了有价值的参考。

填充料和通气对污泥堆肥过程的影响

试验研究了不同配比的填充料和通气状况对污泥堆肥起始升温的影响。结果表明 ,填充料含量高的配比升温速度明显比填充料含量低的配比快 ;高填充料配比的堆体 (填充料占堆料的 1 /2～ 1 /3)在起始升温阶段可以不进行氧气的供给 ;低填充料的配比和加入回流堆肥的配比 (填充料占堆料的 1 /4～ 1 /9) ,由于堆体的孔隙少 ,则必须进行通气量的调节。