具有高比表面积的稻壳灰的制备及其化学活性的研究

Preparation of rice husk ash with high specific surface area and chemical reactivity of the product are reported in this paper. The amorphous rice husk ash with high specific surface area of 311 m^2.g^-1 was produced by heating acid treated rice husk at 700~C for 4 h. The isotherms of rice husk ash are similar in shape to type Ⅱ of Brunaner‘s classification with mesopores being predominant. The rice husk ash has a high chemical reactivity, especially that pretreated with acid. This chemical reactivity depends on ashing temperature and pretreatment conditions. There is an exponential relation between the specific surface area of rice husk ash and the change in the conductivity of saturated Ca(OH)2 solution with rice husk ash, from which the specific surface area can be known according to the conductivity change.     

预氧化-MBR-反渗透工艺深度处理印染废水研究

以某工业园区印染废水处理厂二级生化出水为处理对象,采用预氧化+膜生物反应器(MBR)+反渗透(RO)的组合工艺对其进行深度处理,以达到企业回用水要求。实验结果表明,在进水COD为105~120 mg/L,色度为50倍的条件下,当氧化剂用量为3 mg/L,MBR水力停留时间为3~3.5 h时,组合工艺的出水COD≤5 mg/L,色度≤5倍,电导率≤20μS/cm,出水水质满足企业回用水要求,RO浓水COD≤120 mg/L,色度≤50倍,达到排放标准。     

Thermo-mechanical Analysis of Friction Stir Welding:A Review on Recent Advances

In recent studies, critical research interest exists in the thermo-mechanical analysis of the friction stir welding(FSW) process by numerical simulation. In this review, the thermo-mechanical analysis for FSW is overviewed regarding the computational approaches, the heat generation, the temperature, and the material fl ow behavior. Current concerns, challenges, and opportunities in current studies are discussed considering the application of the thermo-mechanical analysis. Generally, larger computational scale and better computational effi ciency are required to allow better spatial resolution in future analysis. The concepts and approaches demonstrated in the thermo-mechanical analysis for FSW open up quantitative prospects for the design of the FSW process.     

非线性裂纹转子的分形分析

首先介绍了分形的基本概念,给出了机械振动信号主要应用的分析方法。然后研究了非线性裂纹转子的弯曲振动特性,给出了进入倍周期分叉后裂纹转子的时域特性和频域特性。最后对裂纹转子特性进行分形分析,发现并定义了裂纹转子在进入分叉以前轴心轨迹随裂纹角变化的分形特性,并发现裂纹转子在进入混沌前与进入混沌以后具有相似的分形特性;发现了裂纹转子带噪声信号具有两个分维数（二重分形）的复杂特性。     

熔盐电解还原制备TiFe合金

在CaCl2熔盐中采用熔盐电解法由阴极的混合氧化物制备组分可控的TiFe合金。初步探讨了TiFe合金的形成机制,研究了电解时间对电解产物的影响。结果表明,混合氧化物的还原经历了从优先生成铁到逐步形成TiFe2、TiFe的合金化历程,中间产物包括CaTiO3、Fe：TiO4、TiO,电解过程中没有金属钛出现。扩散是混合氧化物熔盐电解反应的控制步骤。     

橡胶防老剂RD不同分析方法的比较

为比较橡胶防老剂RD(TMQ 2,2,4-三甲基-1,2-二氢化喹啉聚合体(C12H15N)n(n=2～4))高效液相色溶剂梯度洗脱的方法和GC-Ms高温裂解方法测定聚合物的含量,采用高效液相色谱法,以水-甲醇作为流动相,检测波长254nm,流速为1mL/min,C18 4.6mm×150mm/5μm色谱柱;GC-Ms法的热分解温度590℃,分解时间6s,热分解室温度为320℃,注射温度250℃,色谱柱DB-1 30mm×0.32mm×0.25μm,升温速度10℃/min,终温为120℃。载气N2流速为1mL/min,FID检测温度280℃,H2流速为30mL/min,空气流速为300mL/min;面积归一法计算含量。结果表明,高效液相色谱法比气相色谱法稳定、可靠,高效液相色谱法测定橡胶防老剂RD的含量优于气相色谱法。     

Phosphate removal in marine electrolytes by zeolite synthesized from coal fly ash

The aim of this study was to examine the influence of seawater electrolytes on removal of phosphate by zeolite synthesized from fly ash (ZFA). A low-calcium ZFA was initially saturated with Na⁺, Mg²⁺, Ca²⁺, Al³⁺, and Fe³⁺. Al- and Fe-ZFA showed nearly complete removal of phosphate regardless of the major seawater electrolytes, pH, and salinity. This result was explained primarily on the basis of the adsorption mechanism through the formation of inner-sphere complexes. The remaining ZFAs showed lower phosphate removal performance, in general with the order of Ca-ZFA > Mg-ZFA > Na-ZFA. Compared with pure water, increase of electrolyte concentration or salinity initially enhanced phosphate uptake but then reduced phosphate removal. The individual presence of major seawater electrolytes all facilitated the retention of phosphate, with CaCl₂ being the most effective. The mechanism for phosphate removal by Na-, Mg-, and Ca-ZFA was due mostly to precipitation. Repeated batch equilibration experiments indicated that, compared with pure water, ZFA had greater sorptive capacity for phosphate (except for Ca-ZFA, whose capacity decreased slightly) and had lower reversibility for sorbed phosphate in marine electrolytes. In conclusion, our results suggest that presence of seawater electrolytes had roughly no effect, or even positive effects, on the removal of phosphate by ZFA.     

塔北哈拉哈塘加里东期多期岩溶古地貌恢复与洞穴储层分布预测

为了认识塔里木盆地北部哈拉哈塘加里东期多期岩溶作用对奥陶系碳酸盐岩储层发育的控制机理,选择不同方法对各期古地貌进行恢复。结果表明良里塔格岩溶期古地貌以丘丛洼地、谷地为主,由北向南发育了多条深切河流,地震剖面证实河流常切穿至一间房组;前志留纪岩溶期,由北向南可划分为潜山岩溶区、碎屑岩浅覆盖岩溶区和厚层覆盖岩溶区,地势北高南低,北部潜山区以微岩溶地貌为主,未发育深切河谷,南部厚层覆盖区为碎屑岩山地,由北向南的水系,汇入碎屑岩尖灭线附近岩溶湖。通过钻录井、岩心、测井解释等资料统计,总结浅覆盖区洞穴型储层主要发育在两个带：一间房组顶面以下0~30 m及50~110 m,对应层位分别为一间房组和鹰山组,厚层覆盖区洞穴型储层主要发育在一间房组顶面以下0~40 m,分带性不明显。结合断裂、古地貌、古水系等因素,认为浅覆盖区下部洞穴型储层及厚层覆盖区洞穴储层主要受控于良里塔格岩溶期径流带岩溶作用,该期南部深切河流为排泄点,控制了储层发育规模及走向。而浅覆盖区上部洞穴型储层受控于前志留纪岩溶期径流带岩溶作用,岩溶湖为径流排泄区,控制了上部洞穴储层发育。     

密封和内阻尼对火箭发动机液氢涡轮泵转子系统动力稳定性的影响

考虑内阻尼的Timoshenko梁一轴有限元离散化转轴,用Muszynska密封力模型描述非线性密封流体激振力,建立实际火箭发动机液氢涡轮泵转子系统的非线性有限元模型。结合已有试验数据,结合打靶法和Floquet 理论研究该系统在刚性支承和柔性支承两种工况下密封和内阻尼对系统稳定性的影响。分析轴承阻尼、轴向雷诺数以及密封各参数在两种支承下对系统临界失稳角速度的影响。     

基于Stribeck摩擦模型的模糊PID控制在伺服系统中的应用

由于采用常规PID算法很难跟踪上基于Stribeck摩擦模型的伺服系统的输入信号,本文采用了模糊PID与传统PID控制相串联的方法,以飞行模拟台伺服系统背景进行仿真实验研究,结果表明,该方法设计简单,能对具有带摩擦的伺服系统进行有效控制,具有较强的鲁棒性和抗干扰性能,并明显优于常规PID控制的性能。