Electropolymerization mechanism of N-methylaniline

A poly(N-methylaniline) (PNMA) film was obtained by chronoamperometry on tin oxide (TO) in dimethylformamide DMF containing 0.5 M sulphuric acid. The PNMA film formation was monitored by in situ UV–vis spectroscopy. A detailed electropolymerization mechanism and reaction pathway of N-methylaniline (NMA) is proposed based on mass spectroscopy (MS) and NMR analysis. The NMA repeating units (both in the film and in the soluble part) were found to be partially dealkylated during electropolymerization. NMA was also electropolymerized in different solvents such as propylene carbonate (PC) and acetonitrile (ACN). Our results show that protonation is not a necessary condition to initiate the electropolymerization of NMA, but it may play a key role for the propagation of longer conjugated chains. The influence of solvents on the film formation and the function of protons are discussed in this paper.     

球形金刚石的形成机制

在 p Si(10 0 )基体上用热丝CVD法沉积了球形金刚石薄膜。用XL30FEG扫描电镜、X射线衍射仪及Raman光谱仪对不同沉积时间的球形金刚石的微观形貌及组成成分进行了研究 ,并对其形成机制进行了分析。结果表明 :球形金刚石的颗粒密度和形核密度一致 ,球形金刚石由微晶金刚石组成 ,晶粒尺寸为 70～ 2 0 0nm ;微晶金刚石是沉积过程中快速二次形核而形成 ,呈无序分布 ;球形金刚石薄膜以二次形核方式繁衍生长     

超微SiO_2的分散机理

用沉降法研究了超微SiO2 在水溶液中的分散行为 ,探讨了超分散剂PSE与传统分散剂的分散效果 ,并通过颗粒间相互作用能计算进一步研究了超分散剂PSE的作用机理。结果表明 :A B嵌段型超分散剂PSE的分散效果最好 ,且不受介质 pH的影响 ,其分散稳定作用的实质是增强了微粒间的静电排斥作用和空间位阻排斥作用 ,并减弱了范德华吸引作用。     

可弯曲伸缩的抽芯机构设计

设计了一种用于注射模的可弯曲伸缩抽芯机构,主要包括成型镶件和抽芯部件。该机构结构简单,动作顺畅,无运动干涉,可实现180°的半圆抽芯,也可用于U形、半圆形、S形中空塑料管件的成型,产品质量好。     

摆动斜楔机构设计

介绍了相邻两处翻边角度不同的侧翻边时,为避免零件之间相互干涉,采用摆动式斜楔代替常规的直线式往复斜楔,节省了模具空间,比旋转斜楔结构更简单、制造成本更低,适用于成形零件尺寸小但工序多的模具。     

Fracture mechanism of scandia-doped zirconia

The bending strength and bending modulus of 5, 9 and 12 mol.% scandia-doped zirconia were investigated as a function of temperature up to 1273 K. The fracture mechanisms of various crystal phases were discussed based on the determined strengths and also the fractographic investigation. The monoclinic phase of the scandia-doped zirconia has a small grain size, which strengthens the material by fracturing in the intergranular mode up to 1273 K. The tetragonal phase fractures transgranularly at room temperature accompanied by a stress-induced transformation, which greatly contributes to a strengthening the material, whereas the strengthening effect disappears at elevated temperature and the fracture mode becomes intergranular. The rhombohedral phase, which only exists below 873 K, also fractures completely transgranularly, leaving patterns of its herringbone structure on the fracture surface, which could be of a rather brittle nature and disappears at higher temperature. The fracture mode of the cubic phase is also transgranular at room temperature, with a relatively smooth fracture surface. It has no particular strengthening effect, but is partially intergranular at high temperature.     

多连杆机构的运动学研究

本文对多连杆压力机机构的运动进行了研究,对多连杆机构的滑块位移与曲柄转角、滑块速度与曲柄转角、滑块加速度与曲柄转角的关系进行研究,推导出的公式可系统研究各杆长对压力机滑块曲线的影响[5];多连杆压力机设计时运用公式计算,准确快捷方便.     

Study of vibration welding mechanism

Abstract

The study on the vertical and horizontal spot vibration welding of Inconel 690 alloy was carried out to observe the dendrite morphologies and estimate the temperature gradient G and growth rate R under different vibration conditions. The purpose is to further understand the mechanism of microstructure changes under vibration. Based on different temperature distributions along vertical and horizontal directions in the centre of a melting pool, it is found that vertical and horizontal vibrations induce the divergence of the nucleates site and grain growth rate then affect the grain morphologies. Vertical vibration welding creates a coarse dendrite structure with sturdy secondary and tertiary dendrite arms, and the X-ray diffraction (XRD) profile of this structure shows a strong (200) peak. Horizontal vibration welding results in grain refinement and a relatively disordered structure, which is reflected by its low XRD intensity. The study shows that vibration affects the weld structure by improving nucleates and changing growth rate.     

Mg-Sn合金的阻尼机理研究

研究了不同的Sn含量（Mg-（1-10）wt%）的Mg-Sn合金在不同状态下（铸态、固溶态、固溶+时效态）的阻尼性能。结果表明随着Sn含量的增加, Mg-Sn合金阻尼性能中与应变相关的阻尼值（阻尼因子Q-1）会相应的增加。Mg-Sn合金阻尼机理为位错阻尼和相界阻尼的共同作用,相界阻尼来自于合金中层片状共晶组织（Mg2Sn与α-Mg）相界面摩擦阻尼。高应变振幅下,Mg-（1-5 wt%）Sn的Q-1因子变化规律为：T4＞F＞T6,位错机制占主导地位;Mg-（7-10 wt%）的阻尼因子Q-1变化规律为：F＞T4＞T6,相界面摩擦阻尼占主导地位。     

超微SiO2的分散机理

用沉降法研究了超微SiO2在水溶液中的分散行为,探讨了超分散剂PSE与传统分散剂的分散效果,并通过颗粒间相互作用能计算进一步研究了超分散剂PSE的作用机理。结果表明：A－B嵌段型超分散剂PSE的分散效果最好,且不受介质pH的影响,其分散稳定作用的实质是增强了微粒间的静电排斥作用和空间位阻排斥作用,并减弱了范德华吸引作用。     

大型机械产品的CE认证

介绍了机械产品CE认证的有关内容和程序.     

Ni-Cr-Mo-S合金的自润滑机理

研究了Ni—Cr—Mo—S合金的自润滑机理。结果表明：合金的显微组织主要是由金属基体和硫化物相与Ni(Cr)合金形成的共晶体两部分构成。随着温度的升高，Ni—Cr—Mo—S合金的摩擦因数逐渐降低；合金材料中生成的共晶体在摩擦面的温度作用下可以变软或熔化形成具有转移性的自润滑膜。在实验的高温下，MoO3和NiO也参与了润滑作用：随着温度的上升，MoO3所起的固体润滑作用逐渐减小，NiO所起的固体润滑作用逐渐增大。在室温摩擦时，轻微粘着磨损为主要磨损形式；在高温摩擦时，磨粒磨损为主要磨损形式，同时也会出现氧化磨损。     

The mechanism of phosphating of steel

A schema of the mechanism involved in the different steps during phosphating of steel is proposed. The effect of electrochemical reactivity as a function of surface finishing, metal microstructure and quantity of inclusions is discussed. Certain aspects concerning crystallization and crystalline reorganization of phosphate layers are defined. The distribution of iron and zinc in the phosphate layers formed by the treatment of steel in zinc phosphating baths was investigated.     

Vortex mechanism in hydrocyclones

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双向复合抽芯机构的设计

针对具有翻盖结构的药用瓶盖,分析了其结构及功能的特殊性,设计了一种新颖的双向复合抽芯机构。机构通过同一斜导柱驱动弯销和滑块,实现侧抽芯滑块和垂直于该滑块滑动方向的型芯在2个相互垂直方向上的顺序抽芯动作。运动分析表明,机构设计合理、工作可靠。     

电磁式自动送料装置的设计

为电机硅钢片的落料设计了一种电磁式自动送料装置，并介绍了其设计思想和设计过程。