Comprehensive analysis on anomalous phenomenon of ethanol-soluble poly(vinyl butyral) membrane for ethanol recovery via pervaporation

Poly(vinyl butyral) (PVB) is selected as a promising ethanol-permselective membrane based on the solubility parameter theory; however, it exhibits anomalous water perm-selectivity in practical pervaporation (PV) process. Comprehensive analysis based on experimental and theoretical methods were carried out to explore the inherent mechanism of the anomalous performance. Firstly, sum frequency generation vibrational spectra and contact angle were developed to quantify the surface reconstruction of membrane in air and ethanol, which indicated that hydrophilic hydroxyl tended to expose on membrane surface with ethanol thus improving the membrane affinity to water. Meanwhile, swelling behaviors proved more water would accumulate in the ethanol swollen membrane. Furthermore, theoretical analysis in terms of sorption and diffusion process, based on the UNIFAC-FV model and Fujita free-volume theory, confirmed the mechanism of anomalous phenomenon of PVB membrane. The comprehensive investigation was expected to provide insights into the basic separation mechanism of PV process.     

A temperature sensor based on the splicing of a core offset multi-mode fiber with two single mode fibers

In this paper, a temperature sensor based on the splicing of a core offset multi-mode fiber with two single mode fibers is proposed and demonstrated experimentally. The temperature sensing principle is analyzed and related experiment is performed. By controlling the core offset and splicing length of the specialty multi-mode fiber (SMMF), two sensors with different temperature sensing properties are obtained, and experimental results show that the temperature sensitivity can be up to 48.76 pm/°C in the range of 25—95 °C. Moreover, it has many advantages, including small size, high sensitivity, and simple structure. So it can be used in potential temperature sensing applications, such as industrial production, biomedical science, power electronics, and so on.     

水蒸气对钙基吸收剂循环煅烧/碳酸化CO2捕集过程中孔结构的影响

利用自制等温测量热重实验台,对钙基吸收剂循环煅烧/碳酸化工艺中水蒸气对吸收剂孔结构影响进行了研究。仅煅烧阶段含有水蒸气时,转化率最低,而仅碳酸化阶段存在水蒸气时,取得最高的碳酸化转化率。煅烧阶段和碳酸化阶段均含有水蒸气与仅碳酸化阶段存在水蒸气转化率类似。采用氮吸附测试了典型工况下的Ca O孔结构。随着循环次数增加,碳酸化转化率降低,比表面积、孔容积逐渐减小。推测煅烧阶段水蒸气通过烧结降低了碳酸化转化率。碳酸化阶段水蒸气通过催化作用提高了转化率,此时孔结构作用并不占主动地位。煅烧和碳酸化均存在水蒸气时,碳酸化阶段水蒸气催化作用更加明显。     

基于调度原理的最优风电装机容量计算

由于风电的装机容量远远超过电网网架的传输能力,使许多地区风电外送受阻,调度人员为保证电网的安全运行,通常将调度周期内电网所剩传输空间的最小值等效为风电场并网的装机容量。这种传统调度方式不仅浪费了调度周期内非最小传输空间的电网传输容量,而且导致大量风电装机容量未被利用,影响了风电的运行效益,为此,在电网现有传输能力基础上,将传统调度方法所确定的风电并网装机容量作为风电装机容量初始值,使风电场装机容量按给定步长递增,然后利用滚动分时段调度方法确定不同装机容量下的风电年发电量,最后以风电最大运行价值为目标,求解风电最优装机容量。以某省实际电网作为算例,算例结果验证了所提方法的可行性与有效性,可大大提高再生能源的利用率。     

超高转速齿轮箱轴承-转子系统性能分析及优化设计研究

以可倾瓦轴承-转子系统为基础,仿真计算分析了轴承跨距、轴径及轴承相关参数对轴承-转子系统临界转速的影响,为高速齿轮箱轴承-转子的优化设计提供依据.研究表明,跨距的影响与转速关系密切;轴径超过54 mm后,影响可忽略;间隙比、支点偏移及预负荷系数对1阶、2阶临界转速的影响趋势基本相同,关系曲线分别为线性、对数和指数形式.根据分析结果,设计了60000 r/min齿轮箱,轴承-转子系统通过空载试验,齿轮箱整体性能满足要求.     

花管与潜水面相交下的冲击试验模型研究

针对潜水井中的冲击试验,在花管与潜水面相交的情况下,由于注入井中的水分潜水面上、下两个部分流入含水层中,造成模型由线性变成非线性的问题,建立新的潜水井中的冲击试验计算模型,给出模型的解析解,并运用溶质浓度示踪技术,算出从潜水面以下部分流走的的水量,最终得到含水层渗透系数。而这与传统研究中,仅通过对测井的有效半径进行修正,来解决这一问题的方法不同。以西藏江雄水库库区一潜水完整井为例,进行现场试验,运用建立的模型,计算出含水层的渗透系数,并将其与Bouwer-Rice潜水井冲击试验模型的计算结果、以及抽水试验的结果进行对比,试验结果表明,建立的模型能够真实地反映地层的渗透特性。对冲击试验标准水头恢复曲线特征进行分析得出：当曲线以较慢速率下降时,才真正反映含水层的渗透特性。     

基于寒地特征的沈北蒲河生态城市规划思考

寒地城市因特殊的气候特征而给城镇居民生产、生活带来许多不便,极大地制约着区域协调可持续发展。针对寒地城市规划实践长期缺乏基础理论指导的现状,本文试图从地域功能综合体的视角引入生态城市理念——生态城市是一个基于"经济—社会—自然环境"的复合生态系统,一个"功能合理、结构明确、形态俱佳的有机协调统一体";并据此从复合生态系统视角分析寒地城市规划的内容组分,从有机协调统一体视角组织寒地城市规划功能结构和空间布局,以期为我国寒地城市规划实践提供一个系统的理论指导框架。最后以沈北蒲河新城为例,进行实证分析。     

大气压冷等离子体活性因子分析及其对克雷伯氏菌细胞膜影响

使用电源电压为26 V交流电激发空气来产生大气压冷等离子体,分别处理样品0、1、2、3、4、5 min。使用发射光谱(OES)对等离子体的活性成分进行分析;采用光谱扫描多功能读数仪(SSMR)对克雷伯氏菌细胞内活性氧进行分析;利用荧光分光光度计(FS)分析克雷伯氏菌细胞膜电位和膜通透性。OES结果表明,在电源电压26 V,放电间隙3 mm时,大气压空气介质阻挡放电等离子体产生的活性因子主要是紫外线和活性氧自由基。SSMR结果显示,与对照相比,克雷伯氏菌细胞内活性氧浓度随着处理时间延长,呈现先升高,再降低趋势。FS结果表明,细胞膜电位升高,促使细胞膜超极化,从而提高细胞膜通透性。研究结果提示,大气压介质阻挡放电等离子体在生物化学工程与技术领域具有潜在的巨大应用价值。     

Correlation between the fracture toughness and β‐crystal fraction in a β‐nucleated propylene‐based propylene–ethylene random copolymer

Propylene‐based propylene–ethylene random copolymer (PPR) has been widely used in the production of hot‐water pipes. To further improve its toughness and thermal resistance, β‐nucleating agents (β‐NAs) are frequently incorporated. In this study, PPR containing 5.6 mol % ethylene units was modified by two kinds of β‐NAs, that is, calcium pimelate and N,N′‐dicyclohexylterephthalamide. The notched Izod impact strength of PPR increased with the addition of the β‐NAs. Drastically different toughening effects were found between the two β‐NAs. The structure of PPR with and without a β‐NA was investigated by calorimetry, X‐ray diffraction, and thermomechanical analysis. The results indicated that the relative fraction of β crystals (k_β) in the injection‐molded specimens was determined by the type and content of β‐NA. The relationship between k_β and the impact toughness was summarized. A critical value for k_β (0.68) was identified for the brittle–ductile transition of PPR. PPR with β‐NA having a k_β greater than 0.68 displayed a higher impact strength than the other mixtures. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42930.     

高黏度齿轮泵运行与结构参数对泵内压力场影响

为解决高黏度齿轮泵普遍存在的噪声、寿命短等问题,针对影响泵内部压力场变化的因素进行研究,包括运行参数：介质黏度、转速、输出压力,结构参数：齿数。与普通齿轮泵相比,高黏度泵泄漏影响减弱,但困油现象引起的径向力不平衡、噪声高、寿命低的问题更加突出。通过CFD方法对高黏度齿轮泵输送介质过程中内部压力场进行全程模拟。结果表明:困油处压力变化范围随着介质动力黏度的增加而升高,升高速率与动力黏度呈指数关系,当动力黏度为3 Pa·s时,升高速率为 70 MPa/s,动力黏度为30 Pa·s时,升高速率达到 877 MPa/s;转速、输出压力与齿数的增加对泵内压力整体影响较小,但会引起困油处压力的迅速升高。“困油”问题是高黏度齿轮泵优化设计需要考虑的关键因素,合理增加卸荷槽尺寸、降低转速与出口压力、减小齿数是解决高黏度齿轮泵困油问题的有效途径。