多晶硅生产中残液搅拌罐密封结构的改造

在处理多晶硅生产中产生的残液时,残液搅拌罐填料密封出现泄漏,针对此问题提出了优化措施,达到了预期效果。     

Enzymatic ring‐opening polymerization (ROP) of polylactones: roles of non‐aqueous solvents

Aliphatic polyesters such as polylactides (PLAs) and other polylactones are thermoplastic, biodegradable and biocompatible polymers with the potential to replace petro‐chemical‐based synthetic polymers. A benign route for synthesizing these polyesters is through the enzyme‐catalyzed ring‐opening polymerization (ROP) reaction; this type of enzymatic process is very sensitive to reaction conditions such as solvents, water content and temperature. This review systematically evaluates the crucial roles of different solvents (such as solvent‐free/in bulk, organic solvents, supercritical fluids, ionic liquids, and aqueous biphasic systems) on the degree of polymerization and polydispersity. In general, many studies suggest that hydrophobic organic solvents with minimum water contents lead to efficient enzymatic polymerization and subsequently high molecular weights of polyesters; the selection of solvents is also limited by the reaction temperature, e.g. the ROP of lactide is often conducted at above 100 °C, therefore, the solvent typically needs to have its boiling point above this temperature. The use of supercritical fluids could be limited by its scaling‐up potential, while ionic liquids have exhibited many advantages including their low‐volatility, high thermal stability, controllable enzyme‐compatibility, and a wide range of choices. However, the fundamental and mechanistic understanding of the specific roles of ionic liquids in enzymatic ROP reactions is still lacking. Furthermore, the lipase specificity towards l ‐ and d ‐lactide is also surveyed, followed by the discussion of engineered lipases with improved enantioselectivity and thermal stability. In addition, the preparation of polyester‐derived materials such as polyester‐grafted cellulose by the enzymatic ROP method is briefly reviewed. © 2017 Society of Chemical Industry     

印尼BAYAH电厂一次风机故障原因分析与处理

本文针对印尼BAYAH电厂一次风机设备故障，详细的分析了故障产生的原因，介绍了三点法找转子动平衡和工装车削式在线修复电机滑环工法，阐述了两种工法的原理以及实施步骤。     

创新式三工位钢丝圈包布机的研究与设计

截止目前,在市面上常见的对轮胎用钢丝圈进行包布缠绕的设备一般都是采用一台包布机对应一个钢丝圈进行包布缠绕,当需要同时进行多个钢丝圈缠绕时则需要多台包布机,且由于单个包布机之间需要保留一定的安全距离,使得整体所需的工厂占地面积较大;此外,通常情况下是一个操作员操作一台包布机,如果需要多台包布机同时工作则需要多个操作员进行操作,这样会导致生产人力成本上升,且人工操作生产效率较低。     

Advances in analysis of total uncertainties in a semi‐invasive residual stress measurement method

The ability to characterise residual stress distribution accurately and over different length scales, particularly deep into an engineering part, plays a significant role in assessing structural integrity. Two most commonly used techniques to measure residual stress fields deep into engineering components include neutron diffraction (ND) and deep‐hole drilling (DHD). As the measurements depend on several physical quantities, they are susceptible to error. The error or uncertainties may turn substantial and compromise the suitability of the results. Although noninvasive, the neutron diffraction technique is neither readily available nor portable and is limited to approximately 60‐mm‐thick specimen; errors associated with results become unacceptable at greater flight paths. Moreover, a mock‐up representing the engineering component is normally used in the ND technique. In contrast, the DHD technique is portable and measures residual stresses with high spatial resolution. An error propagation technique was applied to develop an error analysis procedure taking into consideration various stages of the DHD method and successfully applied to different DHD measurements. An essential feature comprising the effect of plasticity due to the creation of reference hole in the DHD procedure has not yet been taken into account in the error analysis procedure. This paper briefly describes how the uncertainties due to the creation of the initial reference hole can be determined. The effect of plasticity in the drilling procedure is quantified in this study. This error is combined with other sources of error and formulated to determine the total error. An incremental DHD technique was used to measure the complex triaxial residual stress field in an as‐welded circular disc, and the measured data were used to illustrate the total error using the error analysis method developed in the study.     

Electrocatalytic hydrogen evolution of highly dispersed Pt/NC nanoparticles derived from porphyrin MOFs under acidic and alkaline medium

Platinum (Pt)-based electrocatalysts often exhibit an excellent electrocatalytic activity for hydrogen evolution due to their best hydrogen bonding energy, but materials with high Pt content can easily cause aggregation and reduce their efficiency. In this article, Pt-based electrocatalysts with uniform dispersion and high efficiency were fabricated by a successive hydrothermal and calcination method, and the uniformly distributed Pt nanoparticle was mainly due to the anchoring effect of porphyrin ring in porphyrin MOFs, which made the minimized agglomerations as much as possible in the process of high temperature calcination. The results showed that the optimal Pt/NC-850 could reach current density of 10, 50 and 100 mA cm^?2 with only 17, 82 and 152 mV overpotentials, while the Pt/NC-850 also exhibited a superior stability and durability under acidic medium. Impressively, the Pt/NC-850 also had an excellent activity, good stability and durability under alkaline medium.     

拱圈在基坑支护中的应用

珠海市海珠广场基坑支护工程采用双排搅拌桩帷幕墙止水、拱圈支护结构挡土方案。介绍了拱圈支护结构的设计及施工中应注意的问题。经过监测，采用拱圈支护结构变位很小。     

铁基粉末齿环材料的制备

采用高能球磨法制备Fe-2Mn-2Cu-Mo-C-P粉末．研究了粉末形态的变化规律，以及压坯密度、烧结密度与球磨时间的关系．结果表明，球磨8h的粉末经压制烧结，材料密度为7．21g／cm^3。退火后Hv5值为230-240。该材料具有良好的热塑性及硬度，适合粉末热锻法生产齿环．     

东鞍山烧结厂磁浮流程可行性的研究

选用立环脉动高梯度强磁机和新研制的新型捕收剂，东鞍山贫赤铁矿石经实验室试验，采用两段连续磨矿－强磁抛尾－混磁精再磨－正浮选工艺流程，可得到品位大于64％的精矿、铁回收率超过70％的指标。