超声波功率对Ni-Co/ZrO2复合电沉积的影响及电化学研究

在氨基磺酸盐电解质溶液中,采用超声波辅助电沉积的方法,于纯铜板表面制备了Ni-Co/ZrO_2复合镀层。研究了超声波功率对Ni-Co/ZrO_2复合镀层的表面形貌、相结构、显微硬度及耐蚀性的影响。结果表明:超声波功率直接影响复合镀层中纳米微粒的复合量,从而影响复合镀层的结构和性能。超声波功率为240 W时所得复合镀层的显微硬度最高,纳米微粒的复合量最大,耐蚀性最强。同时,超声波功率为240 W时引起的阴极极化最大,有利于纳米微粒与基质金属的共沉积。     

污泥厚度对超声波辅助热风干燥污泥特性的影响

由于在超声波声场中污泥微粒会发生分层现象，声互作用力使得微粒于超声传播方向相垂直的平面上发生凝聚，因此污泥厚度大小对超声波辅助热风干燥污泥特性有着重要的影响。通过实验的方法，对不同厚度污泥在超声波声场中的分层凝聚现象进行观察，发现污泥内部结构的分层现象随其厚度的增加而明显。研究了超声波对不同厚度污泥干燥过程中各时期干燥时长、干燥速率的影响效果，以及分析了湿分有效扩散系数（D_eff）随污泥厚度变化的情况。从实验结果中可以发现，在超声波功率小于135 W范围内，污泥厚度越大，干燥过程中第一降速期时间越长，干燥速率提升效果越差，而对恒速干燥期内干燥速率提升效果更明显；在5、10以及15 mm厚度的污泥中，10 mm厚度的污泥在超声波功率小于90 W的条件下总干燥时长降低幅度最大，干燥速率在各阶段提速也较快；污泥厚度越小，超声波功率对污泥湿分有效扩散系数影响越小，反之影响越大。     

不同黏土成分乳状液超声破乳机理研究

针对超声波破乳机理,利用不同种类黏土,在不同时间、黏土用量、功率条件下对超声波破乳进行实验,根据实验所得油水分离结果进行分析与研究。以无黏土加入的超声波破乳实验为参照,合理地解释了在加入黏土颗粒的情况下超声波破乳不能达到预期分离效果的原因。研究表明,加入黏土后,除实验用高岭土随着用量的增加破乳能力降低,蒙脱土、伊利土、石英砂粉末均在少量加入情况下就能够对超声波破乳产生较大影响。在对黏土影响破乳机理进行进一步研究后,发现并验证了黏土颗粒主要是通过自身与表面活性剂的协同作用来影响油水乳状液稳定性,对超声波油水分离提供了技术支持。     

快速提取复混肥中有效磷的方法

在国标GB15063 2001中,有效磷采用3.75%的EDTA溶液作为提取液,在60℃的水浴中提取1h,该方法比较费时。超声波提取法采用超声波清洗器来完成有效磷的提取,它利用超声波的空化效应,当气体传入液体内部,使内部产生大量的不稳定气泡,而且出现快速形成和破坏的物理效应,液体微粒发生     

超声波作用下具有中性浮升力的微粒凝聚分离

针对超声波作用下悬浮液中具有中性浮升力的微小颗粒 (以下简称微粒 )凝聚分离过程中凝聚过程参数以及声学参数对凝聚过程参数的影响进行了分析研究。同时 ,利用数值模拟预测了微粒的凝聚过程参数 ,并且与解析解进行了比较 ,表明数值计算可靠 ,并且需要作为解析解的补充。     

离子液体与淀粉基复合抗静电剂在PE-HD中的抗静电和力学性能研究

以离子液体和淀粉基抗静电剂及其复配应用于高密度聚乙烯（PE-HD）中,研究了其在PE-HD材料中的抗静电效果和力学性能。结果表明,离子液体与淀粉基抗静电剂复配后在PE-HD材料中有良好的抗静电效果和良好的耐久性,在一定含量下不会降低PE-HD材料的拉伸强度和缺口冲击强度。     

水中超声波脱气的效应研究

超声波脱气技术在化工、冶金、环境以及地热能利用等领域具有现实或潜在的应用价值。但是，目前对空气-水系统中超声波脱气规律的研究还相对较少。开展了空气-水系统中的超声波脱气实验研究，在不同的操作参数下，如超声波电功率、频率等，研究了超声波对气体脱除的实际效果。同时将超声波技术与真空脱气技术相结合，探究其脱气效果。结果表明，在实验条件下，随着超声波频率的升高，脱气效果下降；随着超声波电功率的升高，脱气效果提升；与单独真空脱气相比，超声波与真空脱气结合时，脱气效果显著提升；在流动条件下，随着流量增加，脱气效果降低。通过KI实验和可视化方法对超声过程中的声空化现象进行了研究，研究结果可为超声波脱气的工业应用提供基础指导。     

复混肥中钾的超声波提取法

国家标准GB15063-2001《复混合肥料》中规定的方法是通过沸水提取复混肥料样品中水溶性的钾。沸水提取过程需要30 min,再冷却至室温,转移入容量瓶中定容。这个过程至少需要1 h。超声波法是利用超声波的空化效应,使液体微粒间发生高速激烈碰撞,将复混肥料样品中的钾快速地从样品中分离溶解于水中,提取时间只需5 min,而且不需要冷却,比传统提取方法大大缩短了时间。     

油砂沥青超声波减粘工艺研究

油砂沥青粘度较大,自然状态下不易流动,严重影响了管道输送及加工,针对目前油砂沥青研究中存在的问题,采用超声波进行了减粘的实验研究。实验综合考察了超声波作用时间、温度、超声波频率、超声波功率等因素对减粘效果的影响。实验结果表明,在适当的超声作用时间(20 min)、适宜的温度(30℃)、适宜的超声波频率(20 kHz)和超声波功率(250 W)的条件下,油砂沥青的减粘率可达80%以上。经超声波处理后的油砂沥青粘度略有恢复,但仍远低于处理前的粘度,超声波减粘效果良好。     

浮沉分离法回收HDPE/PP混合物的研究

用自行设计的分离器,以浮沉法分离了回收塑料瓶盖中的高密度聚乙烯(HDPE)和聚丙烯(PP)。研究了混合塑料中HDPE和PP的含量、回收塑料尺寸以及分离液密度等因素对分离效果的影响。结果表明:分离后得到的产物中HDPE和PP的纯度可达到97%以上。     

振荡热管内不同形态纳米颗粒流动及传热特性

主要针对不同形态的纳米颗粒在振荡热管内的流动及热传输特性进行了实验研究。在相同的压力、相同的热管倾角、不同的充液率条件下，对振荡热管内工质分别为Cu-水纳米流体以及Cu-水纳米流体中Cu纳米颗粒沉积后溶液的流动以及热传输特性进行了实验研究，并与工质为蒸馏水时进行了对比实验分析，以此来研究振荡热管内气、液以及纳米颗粒多相流动存在时，对热管传输特性的影响。实验表明：当振荡热管内存在气、液以及不同形态的纳米颗粒多相流动时，对其传热特性会产生很大的影响，在一定条件下会起到强化传热的作用。     

高密度聚乙烯薄膜流变性能的研究

考察了4种HDPE薄膜料的流变性能。结果表明:4种HDPE薄膜料的熔体均为非牛顿流体,在一定范围内表现为假塑性流体特性,即:表观剪切黏度随剪切速率的增大而降低。HDPE膜料的流动指数随着温度的升高而增大,熔体的非牛顿性减弱。4种薄膜料的黏流活化能随着剪切速率的增大呈升高的趋势。7000F对剪切速率及温度都较为敏感;J50-08对温度敏感,加工时可用温度调节其熔体黏度。在210℃,J50-08的熔体强度最小,加工效率最高;F00952的熔体强度最大而加工效率最低。     

Linear low-density polyethylene/high-density polyethylene blends: Effect of high-density polyethylene content on die swell and flow instability

This work aimed to evaluate the effect of high-density polyethylene (HDPE) content and of shear rate on the die swell and flow instability of linear low-density polyethylene (LLDPE)/HDPE blends. The results showed that the die swell of the LLDPE/HDPE blends increased with the increase in the shear rate. At high shear rates, the increase in the HDPE content led to an increase in the die swell of LLDPE/HDPE blends. The surface morphology analysis of the extrudates by optical and scanning electron microscopy revealed the presence of sharkskin and stick–slip flow instabilities in LLDPE and LLDPE/HDPE blends at the shear rates investigated. These instabilities were attenuated with the addition of HDPE and almost disappeared in the LLDPE/HDPE blend containing 50 wt% of HDPE.     

Structure and properties of phase change materials based on HDPE,soft Fischer‐Tropsch paraffin wax,and wood flour

Phase‐change materials based on high density polyethylene (HDPE), soft Fischer‐Tropsch paraffin wax (M3), and alkali‐treated wood flour (WF) were investigated. The blend and composite samples were prepared by melt mixing using a Brabender Plastograph, followed by melt pressing. They were characterized in terms of their morphology, as well as thermal, mechanical, thermo‐mechanical, and water absorption properties. Although SEM micrographs showed some evidence of intimate contact between the WF particles and the HDPE matrix as a result of alkali treatment, poor filler dispersion, and interfacial adhesion were also observed. Partial immiscibility of the HDPE and the M3 wax was noticed, with the WF particles covered by wax. There was plasticization of the HDPE matrix by the wax, as well as partial cocrystallization, inhomogeneity and uneven wax dispersion in the polymer matrix. The HDPE/WF/M3 wax composites were more homogeneous than the blends. The presence of wax reduced the thermal stability of the blends and composites. Both the presence of M3 wax and WF influenced the viscoelastic behavior of HDPE. The HDPE/M3 wax blends showed an increase in the interfacial amorphous content as the wax content increases, which resulted in the appearance of a β‐relaxation peak. The presence of M3 wax in HDPE reduced the mechanical properties of the blends. For the composites these properties varied with WF content. An increase in wax content resulted to a decrease in water uptake by the composites, probably because the wax covered the WF particles and penetrated the pores in these particles. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Gas-liquid flow mass transfer in a T-shape microreactor stimulated with 1.7 MHz ultrasound waves

This paper describes the application of ultrasound waves on hydrodynamics and mass transfer characteristics in the gas-liquid flow in a T-shape microreactor with a diameter of 800 μm.A 1.7 MHz piezoelectric transducer (PZT) was employed to induce the vibration in this microreactor.Liquid side volumetric mass transfer coefficients were measured by physical and chemical methods of CO2 absorption into water and NaOH solution.The approach of absorption of CO2 into a 1 mol· L-1 NaOH solution was used for analysis of interfacial areas.With the help of a photography system,the fluid flow patterns inside the microreactor were analyzed.The effects of superficial liquid velocity,initial concentration of NaOH,superficial CO2 gas velocity and length of microreactor on the mass transfer rate were investigated.The comparison between sonicated and plain microreactors (microreactor with and without ultrasound) shows that the ultrasound wave irradiation has a significant effect on kLa and interfacial area at various operational conditions.For the microreactor length of 12 cm,ultrasound waves improved kLa and interfacial area about 21％ and 22％,respectively.From this study,it can be concluded that ultrasound wave irradiation in microreactor has a great effect on the mass transfer rate.This study suggests a new enhancement technique to establish high interfacial area and kLa in microreactors.     

Rheological properties of polypropylene/high-density polyethylene blend melts. I. Capillary flow properties

Three kinds of isotactic polypropylenes (PP) with different melt flow indexes (MFIs) were melt-blended with three kinds of high-density polyethylenes (HDPE) with different MFI using a screw extruder, and the morphologies and capillary flow properties such as flow curve, entrance effect, Barus effect, and melt fracture were studied. When HDPE contents were 70 wt % or above and PP particles formed the disperse phase, the size of the particles decreased with decreasing viscosity of PP. When HDPE contents were 30 wt % or below and HDPE particles formed the disperse phase, the size of the particles was minimum when the viscosities of PP and HDPE were similar. The die swell ratios of the blends were higher than those of the components. On the other hand, the entrance correction coefficients of the blends were intermediate between those of the components. There was no correlation between the die swell ratio and the entrance corretion coefficient. Therefore, it is not always appropriate to regard the entrance correction coefficient as a measure of melt elasticity in the case of inhomogeneous polymer systems such as PP/HDPE blend.     

Modeling of Particle Removal using Non-contact Brush Scrubbing in Post-CMP Cleaning Processes

Particle removal using non-contact brush scrubbing for post-CMP (Chemical Mechanical Planarization) cleaning is investigated analytically. The removal of SiO₂ and Al₂O₃ particles adhered onto SiO₂ film coated on the wafer surface are considered. The cleaning fluid (H₂O/NH₄OH = 1:25 and 1:200) flowing between the brush and wafer surface is treated as a thin-film fluid flow. The flow field details and its effect on the drag force acting on the adhered particles are discussed. In addition to the drag force, the electrical double layer (EDL) and thermophoretic force effects on particle removal are also considered. It was found that the dominant force in achieving particle removal using a rolling mechanism is the drag force. The EDL and thermophoretic forces have an insignificant effect on particle removal. Based on the results from this study, particles of submicron size can be removed from a wafer surface using higher brush rotation speed and pure deionized (DI) water as the cleaning fluid.     

Short‐time fabrication of well‐mixed high‐density polyethylene/ultrahigh‐molecular‐weight polyethylene blends under elongational flow: morphology,mechanical properties and mechanism

As linear polyethylenes, ultrahigh‐molecular‐weight polyethylene (UHMWPE) and high‐density polyethylene (HDPE) have the same molecular structure, but the large difference in viscosity between them makes it difficult to obtain well‐mixed blends. An innovative eccentric rotor extruder (ERE) generating an elongational flow was used to prepare HDPE/UHMWPE blends within short processing times. Compared with the obvious two‐phase morphology of a sample from a twin‐screw extruder observed with a scanning electron microscope, few small UHMWPE particles were observed in the HDPE matrix for a sample from the ERE, indicating the good mixing on a molecular level of HDPE/UHMWPE blends achieved by the ERE during short processing times. The morphological changes of blends prepared using the ERE evidenced the good integration of HDPE and UHMWPE even though the UHMWPE content is up to 50 wt% in the blends. Moreover, all blends retained most of the intrinsic molecular weight. The good mixing was further confirmed from the thermal, crystallization and rheological behaviors determined using differential scanning calorimetry and dynamic rheological measurements. Importantly, the 50/50 blend presented improved mechanical properties, especially super‐impact strength of 151.9 kJ m^?2 with incomplete‐break fracture state. The strengthening and great toughening effects of UHMWPE on the blends were attributed to the addition of unwrapped UHMWPE long molecular chains. The effective disentanglement mechanism of UHMWPE chains under elongational flow was explained schematically by a non‐parallel three‐plate model. © 2019 Society of Chemical Industry     

高流动性等规聚丙烯与高密度聚乙烯共混改性

研究了高密度聚乙烯（ HDPE ）含量对等规高流动性聚丙烯（ iPP ）力学性能和流动性能的影响。研究表明,随着HDPE含量的增大,冲击强度越来越大,硬度越来越小。 HDPE含量为10％时,拉伸/屈服强度以及弯曲强度出现最大值。共混体系的流动性能随着HDPE含量的增大而减小。     

三相流闭式重力热管的强化传热

将三相流强化传热技术应用于重力热管,构建了三相流闭式重力热管系统.以水为工质,固含率(体积分数)、固体颗粒的种类、大小及加热功率等作为参数,研究并分析了三相流重力热管的传热性能.结果表明:在一定的条件下,三相流闭式重力热管具有一定的强化传热效果.随着加热功率的增加,等效对流传热系数增大.加入φ5.5 mm的聚甲醛颗粒时...