畜禽粪污厌氧消化液自然处理模式技术的研究与应用现状

厌氧消化技术具有能耗低、回收能源、技术成熟等特点,是目前畜禽粪污一级处理的主要应用技术。厌氧消化处理后产生的沼液需要进一步处理利用,而"污水达标排放"仍然是土地紧张地区畜禽粪污处理不得不面临的选择。文章主要综述了3种自然处理工艺(稳定塘、人工湿地、人工砂滤系统)对畜禽粪污厌氧消化液的应用研究情况及其处理效果。概述了厌氧消化液自然处理工艺的优缺点、工艺类型、工艺对比及组合工艺应用、工程运行效果等研究现状及调研情况,最后提出在实践中需针对厌氧消化液的特性组合应用不同自然处理工艺的建议。

Microstructure and thermal conductivity of submicron Si_(3)N_(4) reinforced 2024Al composite

An 2024Al matrix composite reinforced with 36%(volume fraction)β-Si_(3)N_(4) particles was fabricated by pressure infiltration method,and its microstructure and the effect of annealing treatment on thermo-conductivity were discussed.Si_(3)N_(4) particles distribute uniformly without any particle clustering and no apparent particle porosity or significant casting defects are observed in the composites.The combination of particles and matrix is well.The raw Si_(3)N_(4) particles are regular cylindrical polyhedron with flat surface and change to serrated surface in composite due to reactions during fabrication.Thermal conductivity of as-cast Si_(3)N_(4)p/2024 composite is 90.125 W/(m·K)at room temperature,and increases to 94.997 W/(m·K)after annealing treatment. The calculated results of thermal conductivity of the Si_(3)N_(4p)/Al composite by Maxwell model,H-S model and PG model are lower than experimental results while that by ROM model is higher.

耳大神经阻滞联合耳颞神经阻滞在中耳显微手术低阿片化麻醉的应用

目的 探讨耳大神经阻滞(great auricular nerve block, GANB)联合耳颞神经阻滞(auriculo-temporal nerve block, ATNB)用于中耳显微手术低阿片化麻醉的效果。方法 选择择期全麻下行中耳显微手术患者64例,按随机数字表法分为两组:耳大神经阻滞+耳颞神经阻滞组(G+B组)和单纯全麻组(G组),最终每组各纳入30例。G+B组麻醉诱导前在超声引导下进行GANB和ATNB, G组行单纯全身麻醉。两组麻醉诱导方案和麻醉维持方案相同。术后使用舒芬太尼补救镇痛以维持疼痛评分<4分,用甲氧氯普胺止吐以维持恶心呕吐(PONV)评分<5分。监测麻醉诱导后1 min(T1)、手术切皮后1 min(T2)血流动力学参数(MAP、HR)变化;记录瑞芬太尼、丙泊酚用量及持续输注时间、全麻时间;进行PACU(转入后10 min)和术后4 h、12 h、24 h、48 h疼痛VAS评分、PONV评分;统计术后48 h内补救镇痛率和止吐率。结果 组间比较,G+B组瑞芬太尼用量明显减少,切皮后1 min(T2)MAP降低,PACU及术后4 h、12 h疼痛VAS评分、PACU及术后4 h、12 h、24 h PONV评分、术后48 h内补救镇痛率及止吐率均显著低于G组,差异均有统计学意义(P<0.05)。结论 超声引导下GANB联合ATNB可减少中耳显微手术中瑞芬太尼的用量,缓解术中血流动力学变化,降低患者术后镇痛和止吐需求。

Nonlinear temperature characteristic of thermal expansion of Grf/Mg composites

Graphite fiber reinforced magnesium matrix(Grf/Mg)composites were fabricated by squeeze casting technology.M40 graphite fibers were reinforced to AZ91D and ZM6,their thermal expansion behaviors of M40/AZ91D and M40/ZM6 composites in the temperature range from 20 to 490℃were investigated.The results show that the interfacial species and thermal stress have significant influence on the thermal expansion behavior of the composites.Simultaneously,the longitudinal coefficient of thermal expansion of Grf/Mg composites are affected by the thermal stress,interfacial species and yield strength of matrix alloy,it also decreases with increasing temperature and descending rate of longitudinal coefficient of thermal expansion(CTEs)of Grf/Mg composites changed in different temperature ranges.In terms of different descending rates,the curve of coefficient of thermal expansion vs temperature can be divided into three stages.The matrix alloys M40/AZ91D and M40/ZM6 yield at 170 and 155℃in the thermal expansion,respectively.

果园防雹网自动控制系统的设计与实践

为了探讨果园防雹网搭建自动收铺网技术方法,解决防雹网固定式搭建对果树生态产生的不利影响和苹果采收后收网的困难,提升防雹网应用的灵活性,从而提高苹果产量及质量。本文采用单元化设计方法与机电一体化技术,对防雹网自动收铺网和远程控制过程进行了试验。结果表明,通过防雹网搭建自动收铺网技术探讨,结合远程控制技术,在充分发挥防雹网抵御冰雹灾害的同时,利用防雹网对果园地温、阻风、遮蔽等有效作用而消除了不利影响。该技术规范了搭建材料,为搭建用料规范化提供了依据,突破了固定式搭建的制约,提高了果业防灾减灾技术的自动化水平。

Fabrication and thermo-physical properties of TiB_(2p)/Cu composites for electronic packaging applications

TiB_(2p)/Cu composites with high reinforcement content(φ_(p)=50%,58%and 65%)for electronic packaging applications were fabricated by squeeze casting technology.The microstructures and thermo-physical properties of the TiB_(2p)/Cu composites were investigated.The results show that TiB2 particles are homogeneous and distribute uniformly,and the TiB2-Cu interfaces are clean and free-from interfacial reaction products and amorphous layers,the densifications of the TiB_(2p)/Cu composites are higher than 98.2%. The mean linear coefficients of thermal expansion at 20-100℃for TiB_(2p)/Cu composites range from 8.3×10^(-6)to 10.8×10^(-6)/K and decrease with increasing volume fraction of TiB2.The experimental coefficients of thermal expansion agree well with the predicted values based on Turner’s model.The thermal conductivities of TiB_(2p)/Cu composites range from 167.3 to 215.4 W/(m·K),decreasing with increasing volume fraction TiB2.

Effects of extrusion deformation on mechanical properties of sub-micron Si_(3)N_(4p)/2024 composite

Si_(3)N_(4p)/2024Al composite was fabricated by squeeze casting method and treated by extrusion deformation.Microstructure analyses indicate that Si_(3)N_(4) particles in the composite are in cylindrical polyhedron shape.Extrusion deformation is beneficial to uniform distribution of Si_(3)N_(4) particles and improves the relative density of Si_(3)N_(4p)/2024Al composite.Tensile strength of Si_(3)N_(4p)/2024Al composite increases by 76.6%after T6 treatment,and after extrusion and T6 treatment it is by 57.6%more than T6 treatment only.Elastic modulus of Si_(3)N_(4p)/2024Al composite increases a little after T6 treatment but increases by 33.5%after extrusion deformation.

惯性仪表精度漂移的材料问题与尺寸稳定性复合材料设计

陀螺、加速度计等惯性器件是高精度传感器,对零件的微小变形有着极其敏感的反应。因此,惯性器件材料的尺寸稳定性问题一直是提高精度的关键。作者长期研究发现,惯性仪表精度及其稳定性在结构设计确定的情况下与加工、装配有关,但是本质性的因素是材料在长期温度扰动下的"变形""变性""变质"问题。我国关于惯性器件材料尺寸稳定性的研究十分薄弱,材料与工艺技术已经成为制约仪表精度的"卡脖子"问题。本文重点介绍了材料"变形"即在温度扰动下微纳变形的研究结果。首先分析了惯性器件的服役环境以及该服役环境下的材料响应,从而提出复合材料尺寸稳定性设计的基本原理。通过材料设计,为解决低频谐振、复杂结构热应力变形、动载荷弹性变形、长期静载荷微纳米级变形、长期储存下材料时效自发变形等问题提供了有效的材料设计方案。设计制备的仪表级SiC/Al复合材料在核心关键指标上优于铍材,在"高新工程"、"北斗工程"等重大工程中显示出优异的技术效果。