用乙酐合成法制备邻二醇

本文介绍了以过硼酸钠为氧化剂、醋酐为反应介质、浓硫酸为催化剂，将烯烃直接氧化成邻二醇单乙酯，再经碱性水解得到邻二醇的一种新型制备方法     

烯烃与四氧化锇反应条件表述的常见类型

四氧化锇是一种能将烯烃转化为顺式邻二醇的有效氧化剂,烯烃与OsO_4的氧化反应是工业生产上制备顺式邻二醇的高产率方法。本文综述了国内外常见的一些《有机化学》教材中列举的该反应进行的各种条件。     

芥酸甲酯氧化制备十三烷二酸

提出了一条芥酸甲酯氧化制备十三烷二酸的新工艺路线:以过氧化氢和氧气为氧化剂,芥酸甲酯经烯键环氧化、环氧水解、邻二醇氧化裂解等反应制备十三烷二酸。着重研究了烯键环氧化和环氧水解反应中,影响烯键环氧化反应收率和中间产物羟基值的条件参数。结果表明:含邻二醇的中间产物的羟基值越高,十三烷二酸的总体收率越高;采用新工艺路线,十三烷二酸的总收率达到70.3%,具有工业化应用前景。     

过渡金属多相催化剂催化的分子氧选择性氧化邻二醇研究进展

邻二醇选择性氧化断键生成醛、酮和羧酸是重要和基本的有机反应,氧化剂通常采用化学计量的高碘酸盐或四乙酸铅,无论从经济还是环保的角度考虑,这些传统方法都有违绿色化工的发展理念。理论上以分子氧为氧化剂选择性氧化邻二醇断键的副产物只有水,而且分子氧廉价易得,因而具有环境友好和经济可行的双重优势。经过多年探索,人们已发展了多个基于不同过渡金属为活性组分的多相催化剂或催化体系用于分子氧选择性氧化邻二醇断键反应,如钌、金、锰、钴,为未来广泛应用奠定了基础。本文将按贵金属和非贵金属分类综述此类催化剂及相关反应工艺的研究进展,并指出该领域的发展方向     

纳米金催化剂研究进展

比较详细的介绍了金催化剂的应用研究情况．尤其对CO的常温脱除、富氢条件下CO的选择性氧化．邻二醇的选择性氧化以及烃类的选择性氧化等反应过程进行了较为详细的介绍,具有一定的参考价值。     

邻苯二甲醛合成新工艺研究

邻苯二甲醇在乙酸水溶液中通过硝酸氧化得到目的产物邻苯二甲醛。在单因素实验基础上进行了正交实验,考察醇/酸摩尔比、反应温度、反应时间、醋酸用量等对产品收率的影响。结果表明,优化工艺条件为邻苯二甲醇与硝酸的摩尔比1∶2.5,反应温度80℃,反应时间1 h,收率可达76.0%,含量99.5%。     

N-乙酰苯甘氨酸的制备

以3-苯基缩水甘油为起始原料,通过Ritter反应引入氨基结构单元,随后以高价态金属钌氧化切断邻二醇结构,生成羧基片段,得到目标化合物N-乙酰苯甘氨酸。     

亚硫酸氢钠参与烯烃与四氧化锇反应的机理

烯烃与OsO_4发生氧化反应,中间产物是环状锇酸酯,再经水解反应转变为产物顺式邻二醇,酯水解时要用还原剂。本文给出了亚硫酸氢钠作还原剂参与该反应的可能反应机理。     

邻苯二甲醛合成新工艺研究

邻苯二甲醛是重要的有机合成中间体，可用作胺类生物碱的试剂、荧光计组胺的测定等。目前邻苯二甲醛的合成是通过邻二甲苯侧链氯化生成四氯邻二甲苯，再水解生成邻苯二甲醛，收率较低。本文通过硝酸氧化邻苯二甲醇来合成邻苯二甲醛，取得了理想的效果。     

间接电解氧化合成邻硝基苯甲醛的研究

以三氧化铬为氧化剂，在浓硫酸、冰醋酸、醋酸酐溶液里，将邻硝基甲苯氧化为邻硝基苄叉二乙酸酯，后者经水解得邻硝基苯甲醛。氧化反应后的溶液中岂有　Ｃｒ￣（３＋），浓缩后，在带隔膜的电解槽中，使用铅电极进行电解氧化，重新得到三氧化铬，使其循环使用。     

连续聚酯装置增容

叙述该装置增容的各项措施。在充分利用原有厂房、设备的基础上 ,经过物料衡算 ,调整部分设备和部件解决物流瓶颈 ;更换终聚釜气相出口挡板 ,由圆形换成扇形 ,并尽量缩短与出口的距离以防止真空系统堵塞。浆料总量比保持在 1.74,酯化温度提高 2～ 3℃ ,压力增加 5～ 8kPa,停留时间不变或略有缩小 ;预缩聚Ⅱ的液位加大到 45 % ,升高温度 ,余压降低到1.3kPa ,搅拌转速调为 8.9r/min ;终缩聚液位增加到 49% ,并适当提高搅拌速度等。当熔体日产量由 32 5t提到 35 3t时 ,切片质量指标没有明显变化 ,一等品率在 99%以上。     

工业大麻秆的显微构造和纤维形态研究

大麻秆芯是大麻的废弃物,一种优质的木质纤维原料。为了更好地开发和利用这种原料,论文主要对大麻秆的显微构造和纤维形态进行了研究,结果表明大麻秆的显微构造类似于阔叶材的散孔材。大麻秆皮部的纤维平均长度为22.7 mm,平均壁腔比为0.40,平均长宽比为705.38,83.5%纤维的长度为11～30 mm,72%的细胞长宽比为310～900,72%的壁腔比为0.11～0.50;是一种长度大、壁腔比小、长宽比大的优质纤维原料。而木质部的纤维平均长度为0.65 mm,平均壁腔比为0.32,平均长宽比为29.53,92%纤维的长度为0.41～0.90 mm,91.5%纤维的长宽比为11～50,66%纤维的壁腔比为0.11～0.40;是一种长度中等,长宽比大,壁腔比小的优质原料,可用于造纸和人造板制造的工业原料。     

Adhesion of RFL-coated aramid fibres to elastomers: The role of elastomer–latex compatibility

The performance of fibre-reinforced composites is strongly dependent on the nature and the strength of the fibre–matrix interface. Good interfacial bonding is required to ensure load transfer from matrix to reinforcing fibres. For rubber-reinforced composites, resorcinol formaldehyde latex (RFL) is known as a fibre surface coating which is able to provide good adhesion between rubber and fibres. In the present study, aramid fibres are investigated, because of their significantly higher modulus and strength, compared to other commercial fibres. Their adhesion after being coated with RFL, in compounds based on natural rubber (NR) and in NR blended with a small amount of styrene butadiene rubber (SBR) is investigated. It is shown that though having very similar tensile properties, the latter compound has much better adhesion to RFL which is also less sensitive to RFL ageing, compared to the pure NR compound. It is argued that an interphase region is formed between RFL and the elastomer, which is stronger for the compound containing SBR due to its enhanced compatibility with the latex part of the RFL.     

Universal sequential outlier hypothesis testing

Universal outlier hypothesis testing is studied in a sequential setting. Multiple observation sequences are collected, a small subset of which are outliers. A sequence is considered an outlier if the observations in that sequence are generated by an “outlier” distribution, distinct from a common “typical” distribution governing the majority of the sequences. Apart from being distinct, the outlier and typical distributions can be arbitrarily close. The goal is to design a universal test to best discern all the outlier sequences. A universal test with the flavor of the repeated significance test is proposed and its asymptotic performance, as the error probability goes to zero, is characterized under various universal settings. The proposed test is shown to be universally consistent. For the model with at most one outlier, conditioned on the outlier being present, the test is shown to be asymptotically optimal universally when the typical distribution is known and as the number of sequences goes to infinity when neither the outlier nor the typical distribution is known. With multiple identical outliers, the test is shown to be asymptotically optimal universally when the number of outliers is the largest possible and with the typical distribution being known, and its asymptotic performance with neither the outlier nor the typical distribution being known is also characterized. Extensions of the findings to models with multiple distinct outliers are also discussed. In all cases, it is shown that the asymptotic performance guarantees for the proposed test when neither the outlier nor the typical distribution is known converge to those when the typical distribution is known as the number of sequences goes to infinity.     

A global optimization method based on multi-unit extremum-seeking for scalar nonlinear systems

Finding the global optimum of a nonlinear function is a challenging task that could involve a large number of functional evaluations. In this paper, an algorithm that uses tools from the domain of extremum-seeking is shown to provide an efficient deterministic method for global optimization. Extremum-seeking schemes typically find the local optimum by controlling the gradient to zero. In this paper, the multi-unit framework is used, where the gradient is estimated by finite difference for a given offset between the inputs. The gradient is pushed to zero by an integral controller. It is shown that if the offset is reduced to zero, the system can be made to converge to the global optimum of nonlinear continuous static, scalar maps. The result is extended to constrained problems where a switching control strategy is employed. Several illustrative examples are presented and the proposed method is compared with other methods of global optimization.     

粗糙集与模糊推理相集成的过程建模方法及其应用

针对复杂化工过程机理建模困难的问题,采用适应性较广的模糊方法经验建模,鉴于模糊法对于高维、强相关的样本数据很难导出规则,本文提出先用粗糙集方法消除冗余性,约简系统,获取最小规则集,在此基础上构建结构合理、参数可适当初始化的模糊-神经网络,并采用LM算法训练,收敛速率快,模型预测性能良好.将此法用于PTA装置溶剂脱水塔精馏过程的经验建模,效果令人满意,性能优于现代统计方法和前馈神经网络.     

Experimental investigation of the behavior of variably confined concrete

The behavior of concrete subject to variable levels of confining pressure under concentric axial loading is presented. An extensive experimental investigation of this behavior, using FRP-confined concrete cylinders, is used to develop an understanding of the relationships required to accurately model the behavior of concrete subject to passively induced varying levels of confinement. In particular, the relationship between transverse and longitudinal strains—the dilation relationship—is investigated and a model for this behavior, based on the stiffness of the confining materials, is proposed.Concrete compressive strength is observed to increase with increasing confinement. Axial strain capacity is observed to increase to a greater degree than the compressive strength resulting in a more ductile axial stress-strain behavior for confined concrete as compared to unconfined concrete. The axial stress-strain behavior is also observed to change from parabolic to bilinear as the level of confinement is increased.     

微波化学反应器中微波辐射器的一体化设计与优化

讨论了一种用于微波化学反应器中的微波辐射器的一体化设计与优化方法。辐射器在工作过程中温度变化剧烈,由此产生的热应力可能造成辐射器破裂,导致反应器不能正常工作,甚至出现爆炸。为避免出现上述现象,基于有限元方法,首先根据电磁场边界条件,对辐射器的传输特性进行分析,初步优化其结构参数,保证辐射器的反射系数尽可能小,以减小微波能量在传输过程中的损耗,然后采用多物理场耦合分析方法,对辐射器进行优化设计,降低了辐射器工作过程中产生的热应力,并避免了在结构突变以及衔接部位产生过大的热应力,改善了辐射器的结构稳定性。     

木质素对糖蜜酒精废液的脱色效果

用活性炭脱除糖蜜酒精废液色素是行之有效的方法,但由于其成本过高制约了该方法在实际中的应用。作者提出用造纸黑液提取的木质素替代活性炭脱除糖蜜酒精废液色素的新治理方法,可以使脱色率达95％,COD去除率达82％。这种方法处理效率高,成本低,且工业化应用的可能性大。     

提高MCC控制电源可靠性的探讨

马达控制中心(MCC)控制电源的质量直接关系到电机传动控制系统的可靠性。由于交流电源易受外界电网的影响,自身容易出现故障,用电设备对其要求又很高,容错能力差,所以其可靠性无法满足生产工艺的需要。而直流电源无相位、频率和同步的约束,线路简单,易于隔离、储能,多层并联冗余设计,是提高传动控制可靠性的简单易行的方法。通过使用24 V路、负荷端短路等故障,测试直流母线电压的变化及继电器动作的准确性,证明所设计的直流电源稳定可靠。