Effect of FA chain length on normal- and reversed-phase HPLC of phospholipids

Forty-seven saturated synthetic diacyl PA, PC, PE, PG, and PS and five unsaturated diacyl phospholipids (PL) underwent normal- and reversed-phase (RP) HPLC with isocratic isopropanol/hexane/water (5∶4∶1) and methanol/chloroform/acetonitrile/water (79.5∶9∶8∶3.5) mobile phases, respectively. For normal-phase HPLC, capacity factors (k′ _i ) decrease with chain length (n) of the two identical PL FA residues, whereas the opposite occurs with RP (C₁₈)-HPLC. Plots of In k′ _i vs. n for individual PL classes are in general curved, violating the linear free-energy relationship. For PL of the same n but with different head groups, k′ _i with normal-phase HPLC varies as PE<PG<PA<PS<PC, except when n≥16, when the order is PE<PS≈PA≈PG<PC. For RP-HPLC, the order of k′ _i values is PG<_A≈PS≤PC≈PE until n≥16, when it is PA≈PG<PS≪PC≈PE. With normal-phase HPLC, k′ _i values of PL with unsaturated FA of n=18 are ordered as PE<PA<PC. Increasing degrees of unsaturation lead to increasing k′ _i .     

24脉波移相牵引整流变压器网侧绕组研究

对24脉波移相牵引整流变压器网侧绕组所涉及的相关问题进行了研究,提出了延边三角形连接的网侧绕组电压、电流、匝数、容量及移相角的计算方法.     

聚丙烯装置高负荷试验与扩能改造

通过对聚丙烯装置高负载生产试验,对聚丙烯装置聚合反应系统、气蒸、干燥及回收系统的观察分析,找出提高装置生产能力的瓶颈,为装置扩能改造设计方案的确定提供依据,并为同类装置扩能改造提供经验。     

灰色关联分析和多元二次非线性回归分析模型研究及应用

基于大庆油田采油二厂压裂措施资料,运用灰色关联分析方法选取对裂缝导流能力影响较大的因素,然后运用多元二次回归分析做进一步的定量研究,并与DPS系统的分析结果进行对比。结果表明,灰色关联分析可以较好的得到与裂缝导流能力关系密切的因素,回归分析可以得出因素间的具体定量关系,且回归分析计算的精度较高,多元二次回归分析和DPS平均拟合误差分别为0.940%、0.916%,预测平均误差分别为1.850%、1.831%,研究为油田开发动态数据规律研究提供了有效的方法。     

Numerical and experimental study on the biofiltration of toluene vapor

We have solved both steady state and transient problems on the biofiltration of toluene vapor. The effect of inlet toluene concentration and inlet gas-flow rate on the removal rate of toluene and the elimination capacity of a lab-scale biofilter has been investigated. In this study, the effectiveness factor was a function of pollutant concentration. The dynamic solutions show good agreement with experimental results. At an inlet toluene concentration of 100 ppm, the diffusion of toluene into biofilm was obviously a rate determining step. Above 200 ppm, however, biofilm already showed full activity. The steady-state simulation confirmed that the change of elimination capacity obtained by increasing only inlet toluene concentration was the same as that obtained by increasing only flow rate of contaminated air. The maximum possible performance is about 20 g/m³h with no addition of nutrients.     

基于免疫遗传算法的车间动态调度

提出了一种求解车间动态调度问题的免疫遗传算法。该方法在遗传操作过程中,运用免疫机理提取疫苗,并对进化种群进行免疫操作,从而有效地抑制了遗传算法的“早熟”和搜索效率低下的问题;此外,该算法在解码操作过程中引入设备能力空间的概念,从而将设备的加工能力作为约束条件动态引入,有效地解决了车间动态调度和再调度方案的一致性和连续性问题。实例表明该算法能够满足车间动态调度的要求。     

汽车尾气净化催化剂用Ce_xZr_（1-x）O_2固溶体的研究进展

综述了CeO2和CexZr1-xZr1-xO2固溶体在汽车尾气净化催化剂重要作用、铈锆氧化物的体相结构及影响铈锆氧化物固溶体储养能力（OSC）和织构热稳定性的因素,并对其在催化剂中的应用作了简要陈述。     

Origin of Capacity Fading in Nano-Sized Co3O4 Electrodes: Electrochemical Impedance Spectroscopy Study

Transition metal oxides have been suggested as innovative, high-energy electrode materials for lithium-ion batteries because their electrochemical conversion reactions can transfer two to six electrons. However, nano-sized transition metal oxides, especially Co₃O₄, exhibit drastic capacity decay during discharge/charge cycling, which hinders their practical use in lithium-ion batteries. Herein, we prepared nano-sized Co₃O₄ with high crystallinity using a simple citrate-gel method and used electrochemical impedance spectroscopy method to examine the origin for the drastic capacity fading observed in the nano-sized Co₃O₄ anode system. During cycling, AC impedance responses were collected at the first discharged state and at every subsequent tenth discharged state until the 100th cycle. By examining the separable relaxation time of each electrochemical reaction and the goodness-of-fit results, a direct relation between the charge transfer process and cycling performance was clearly observed.     

Capacity fading on cycling nano size grains of Li1.1V3O8, electrochemical investigation

The electrochemical characterization related to the capacity fading of Li_1.1V₃O₈ nano grains has been investigated. It reveals that capacity loss is associated to the use of liquid electrolyte and that it mainly stems from the active material irrespective of the nature of the liquid electrolyte, the water content, synthesis routes and the positive electrode chemistry. SEM and in operando XRD experiments allow elucidating undergoing physical processes. A film forms from electrolyte decomposition on the surface of the electrode and progressively propagates on cycling through the electrode thickness. Embedded grains become either less or none electrochemically reactive. In the former case, embedded grains give rise to strongly polarized and energetically less favored processes. In the latter case the capacity is not accessible anymore within the potential range resulting in capacity fading.     

Two-commodity reliability evaluation of a stochastic-flow network with varying capacity weight in terms of minimal paths

A real-life manufacturing system can be modeled as a stochastic-flow network in which nodes stand for the machine stations, and arcs stand for the shipping media. In terms of minimal paths (MPs), this paper presents a stochastic-flow network model with four characteristics: (1) both nodes and arcs have multiple possible capacities, and may fail; (2) each component (arc/node) has both capacity and cost attributes; (3) two-commodity are proceeded; and (4) the capacity weight varies with arcs, nodes, and types of commodity. We study the possibility of two-commodity to be transmitted through this network simultaneously under the budget constraint. Such a possibility is named as the system reliability. The MPs play the role of media to describe the relationship among flow assignments and capacity vectors. Subsequently, a simple algorithm, in terms of MPs, is proposed to evaluate the system reliability. From the capacity management and decision making viewpoints, managers may adopt the system reliability as a performance index to measure the system capacity and finally to determine if it meets the customers’ orders or not.