Mathematical modelling and analytical solution for workpiece temperature in grinding

This paper deals with modelling the workpiece temperature field produced during the grinding process. The proposed model is given in terms of a two-dimensional boundary-value problem where the interdependence among the grinding wheel, the workpiece and the coolant is described by two variable functions in the boundary condition. An explicit integral form solution is constructed using the Laplace and Fourier transforms and the Green’s function method.     

试样研磨对铜合金主要元素分析结果的影响

本文从砂带，研磨方法，试样表现状况三个方面，分析了试样研磨对铜合金主要元素测试结果的影响。     

Influence of two grinding methods on the uncertainty of determinations of heavy metals in atomic absorption spectrometry/electrothermal atomisation of plant samples

 Chemical analyses of trace elements are affected by relatively high analytical errors due to the different steps of the laboratory procedures: samples grinding, mineralisation and instrumental measurements. In the present communication, the influence of the grinding phase on the global uncertainty of Pb, Cd, Ni and Cr determinations in plant samples by the classical method of atomic absorption spectrometry/electrothermal atomisation (AAS-ETA) after dry ashing is quantified. Two grinding machines, a planetary mill with balls and jars of agate versus a stainless steel grinder were compared by analysing leaf samples of cucumber, strawberry, kiwivines, apple trees and grapevines from agricultural experimental plots under controlled conditions. Variance components due to the difference between grinding methods and experimental plots were estimated. Further, the simultaneous effects of the grinding methods on all considered metals have been evaluated by analysis of variance. With the stainless steel grinder, on average, higher levels of the considered heavy metals were obtained (up to 67% of the mean values). On average, the increments were similar for metals contained in steel (Ni and Cr) and those not contained (Pb and Cd). The true causes of these differences need further investigation to determine whether the higher metal detection is due to possible contamination, to a different grinding quality or to other reasons. Finally, the grinding methods did not seem to affect the combined uncertainty of the analyses. Received: 3 November 1997 · Accepted: 29 November 1997     

An Expeditious Room‐Temperature Grinding Method to 5‐Aryl‐2‐furoyl Substituted Thioureas and Thiosemicarbazides

Abstract

An expeditious, one‐pot, high‐yielding and solventless approach to 5‐aryl‐2‐furoyl substituted thioureas and thiosemicarbazides by room‐temperature grinding method is described.     

Efficient Synthesis and Plant-Growth Regulating Activities of 1-Aryloxyacetyl-4-(2-benzofuroyl)- semicarbazides

Under grinding and solvent-free conditions via a one-pot procedure, the reaction of 2-benzofuroyl chloride with ammonium thiocyanate and aryloxyacetetic acid hydrazide afforded 1-aryloxyacetyl-4-(2-benzofuroyl)-thiosemicarbazide. Not isolating, the resulting thiosemicarbazides were further ground with HIO₄·H₂O to give a series of new 1-aryloxyacetyl-4-(2-benzofuroyl)-semicarbazides in high yields. Structures of compounds are confirmed by elemental analyses and IR and ¹H NMR spectra.     

Oxidative Coupling Reaction of N,N‐Dialkylanilines with Cerium(IV) Ammonium Nitrate in the Solid State

Oxidative coupling reactions of N,N‐dialkylanilines with cerium(IV) ammonium nitrate can be achieved by grinding at room temperature in the absence of solvents.     

水性颜料体系无树脂色浆的制备与应用

中性墨水属于热力学上不稳定的颜料悬浮体系,选择低黏度、高稳定性的色浆是保证墨水体系分散稳定性的重要手段之一.基于此,以颜料炭黑和酞菁蓝为着色剂,配合超分散剂(EK43)与协同增效剂(BM10),制备了两款适用于中性墨水体系的无树脂色浆.首次从色浆粒径与体系分散稳定性角度出发,确定了EK43、BM10用量以及最佳研磨时间...     

A simple and efficient method for solvent-free iodination of hydroxylated aromatic aldehydes and ketones using iodine and iodic acid by grinding method

<正>Green,mild and efficient iodination of hydroxylated aromatic aldehydes and ketones using iodine and iodic acid in the solidstate by grinding under solvent-free conditions at room temperature.This method provides several advantages such as environmentally friendly,short reaction times,high yields,non-hazardous and simple work-up procedure.     

Solvent free synthesis of trifluoromethyl tertiary alcohols by cross Aldol reaction

Exceedingly fast preparation of trifluoromethyl tertiary alcohols has been accomplished from methyl ketones and trifluoromethyl ketones under solvent free conditions by cross Aldol reaction. The reaction was achieved in the presence of common inorganic base by grinding method at ambient temperature to give β-trifluoromethyl-β-hydroxyl ketones in high yields (up to 95%).     

K417材料缓进深磨烧伤色与氧化膜结构的研究

本实验应用X射线光电子谱仪,在获取磨削弧区温度的基础上研究了K 417镍基铸造高温合金表面氧化膜的成分和结构,其中包括正常缓磨后及出现不同层次烧伤色后的氧化膜,结果表明,氧化膜不是出现烧伤色的试样所特有,对正常缓磨试样也存在,只是氧化膜厚度不同而已。磨削弧区温度越高,烧伤色层次越深,对应的氧化膜厚度亦越大。氧化膜是Ni、Cr、Ti、Al等元素的氧化物及晶体态Ni等以掺合结构所组成。