电热泵用于蔬菜温室供热的经济性分析

现代化蔬菜温室是我国都市农业发展中的一个重要组成部分，目前这类温室的冬季加热均以燃煤方式为主．伴随着越加严重的城市环境污染，温室供热系统也面临着改造问题，需要引入清洁供热方式，热泵供热是其中的一种．本文以上海地区现代化蔬菜温室为研究对象，分析了蔬菜温室中使用电热泵供热的运行成本，并与燃煤供热方式进行了对比．就热泵供热系统在温室中的应用前景及可行性、经济性进行了分析，为热泵在温室供热系统中的应用提供了可参考依据．     

热力膨胀阀在空气源热泵热水器系统中稳定特性的实验研究

本文对热力膨胀阀在空气源热泵热水器的稳定特性进行了实验研究.通过不同热力膨胀阀开度下的实验数据,分析了热力膨胀阀在系统中的稳定特性.分析了热力膨胀阀在空气源热泵热水器全年运行工况中存在的局限性.提出保证系统稳定运行的方法与建议;指出制冷剂充注量是系统稳定运行的另一个重要因素,只有同时很好地把握住热力膨胀阀开度和制冷剂充注量,才可能使系统运行在最佳工况.     

呋喃-乙酸分子间相互作用的量子化学研究

用密度泛函理论B3LYP方法选取6-311＋＋G(d,p)基组对呋喃-乙酸复合物进行了量子化学计算研究, 通过在相同水平下的频率振动分析发现了该势能面上6个极小值点, 其最稳定构型对应一强O…H—O型氢键, 其结合能在消除基组重叠误差后为－20.87 kJ•mol^－1. 通过自然键轨道(NBO)分析, 研究了电荷转移及轨道相互作用. 通过自洽反应场(SCRF)理论中的Onsager 溶剂模型在介电常数分别为1.0, 2.247, 4.9, 7.58, 10.36, 20.7, 32.63, 38.2, 46.7, 78.39的不同溶剂环境下重新优化呋喃与乙酸势能面上最稳定构型A, 研究了溶剂对呋喃-乙酸复合物几何构型、电荷分布、偶极矩以及结合能的影响. 发现溶剂化作用增大了呋喃与乙酸分子间的结合能, 导致O…H距离减小, H—O振动频率红移. 当溶液介电常数在1.0～32.63范围时, 溶剂效应十分显著, 当介电常数大于32.63后, 溶剂化作用几乎达到了极限.     

Aggregation of sodium 1-(n-alkyl)naphthalene-4-sulfonates in aqueous solution: micellization and microenvironment characteristics

In aqueous solution, the micellization and microenvironment characteristics of the micelle assemblies of three anionic surfactants, sodium 1-(n-alkyl)naphthalene-4-sulfonates (SANS), have been investigated by steady-state fluorescence and time-resolved fluorescence decay techniques using pyrene, Ru(bpy)3(2+), and 1,6-diphenyl-1,3,5-hexatriene as fluorescence probes. The critical micelle concentrations (cmc's), effective carbon atom numbers (neff's), hydrophilic-lipophilic balances (HLBs), mean micelle aggregation numbers, micropolarities, and microviscosities of these surfactant micelles have been determined. The logarithmic cmc of the alkylnaphthalene sulfonates decreases linearly with an increase in the neff. The logarithmic aggregation number of the alkylnaphthalene sulfonates increases linearly with an increase in the neff. However, in contrast to the alkylsufonates and the alkylbenzene sulfonates, the aggregation for these alkylnaphthalene sulfonate molecules is less sensitive to the increase in the neff. The micropolarity of these alkylnaphthalene sulfonate micelles is less sensitive to the increase in the alkyl chain length and is lower than that of sodium dodecyl sulfate (SDS). The microviscosity of these alkylnaphthalene sulfonate micelles increases with an increase in the alkyl chain length and is lower than those of nonionic surfactants and zwitterionic surfactants. These results suggest that naphthyl rings have a notable effect on the micellization of SANS.     

Studies of synergism for lowering dynamic interfacial tension in sodium alpha-(n-alkyl) naphthalene sulfonate/alkali/acidic oil systems

Alkylnaphthalene sulfonates with high purity were selected as model components to research synergism for lowering interfacial tension (IFT) in surfactant/alkali/acidic oil systems. The dynamic IFTs between alkylnaphthalene sulfonates with different alkyl chain length and n-decane, oleic acid model oil, or Shengli crude oil were measured. The results showed that the alkylnaphthalene sulfonates with different alkyl chain lengths had different synergism with different acidic components and their ionized acids under the same conditions. The synergism for lowering dynamic IFT in alkylnaphthalene sulfonate/alkali/acidic oil systems was controlled by alkylnaphthalene sulfonate concentration, alkyl chain length, alkali concentration, alkali type, and oleic acid concentration: optimal physicochemical conditions were necessary to the best synergism. This indicates that the synergism among added surfactant acidic components in crude oil and their ionized acids is controlled by the ratio of their interfacial concentrations.     

Enantiomeric separations of four basic drugs containing N-alkyl groups by a RP-HPLC system using SBE-β-CD as chiral mobile phase additive

The chiral separations of four pharmaceutical racemates which contain N-alkyl groups were satisfactorily resolved using SBE-β-CD as a chiral mobile phase additive(CMPA)in a RP-HPLC system(the resolution is 2.701 for ondansetron hydrochloride,1.996 for sulpiride,1.293 for clenbuterol hydrochloride and 0.816 for omeprazole).In addition,the effects of different parameters such as CD type and CD concentration were investigated.The separation mechanism arises through the combination of several potential interactions,including electrostatic interactions as well as hydrogen bonding interactions and hydrophobic inclusion interactions,which allow for the SBE-β-CD–drug complexation with strong stereoselectivity and stability.The resolution also relates to the number and location of N atoms in the enantiomers.This method will be applicable to the isolation of various types of biologically important enantiomers containing N-alkyl groups.     

压气机非定常叶顶间隙流的数值模拟研究

利用数值方法研究了某低速轴流孤立压气机转子中非定常叶顶间隙流的流动特征和频率特性。结果显示转子顶部区域的压力脉动主要来源于叶顶泄漏涡的非定常波动。波动的具体形式表现为泄漏涡瞬态空间位置、尺度和形态的周期性变化,波动频率为1266 Hz。     

一种控温热管理器的传热传质分析

本文针对余热回收中控制热源温度的需求,提出了热管理器概念并研制开发了实验样机.本文建立了热管理器内部传热传质二维模型,研究其工作机理.模拟结果表明,不凝气具有有效的凝结换热阻隔作用.工况变化时,蒸汽覆盖段长度显著变化,而这一区域内饱和蒸汽温度变化很小,说明热管理器具有良好的控温性能.计算结果与实验数据吻合很好,验证了理论模型的正确性.     

直膨式太阳能热泵热水器过热度PI控制的实现

从自身特性和应用要求来看,热力膨胀阀作为直膨式太阳能热泵热水器的节流元件,调节品质不高.本文以电子膨胀阀作节流元件,采用太阳辐射强度的开环比例控制与集热板过热度的闭环反馈PI控制相结合的控制方案,通过实验研究的方法逐步制定控制策略,分三种不同情况采取特定参数控制集热板出口过热度.经实验验证,可以实现典型工况下过热度的准确、稳定控制.指出,合理改进电子膨胀阀开度的控制算法,并结合变频压缩机实现对制冷剂流量的串级控制,是实现系统全年优化运行进一步的研究方向.     

Preparation,Mechanism, and Supramolecular Structure Study of a Novel Benzimidazole-Hydrate

Abstract  

A novel bis[2-(2-chloro-4-fluorophenyl)-1H-Benzimidazole]-hydrate was prepared from Schiff base, and its single crystalline was obtained. The single crystalline was characterized by X-ray crystallography, and the results shows that the title complex belongs to the triclinic system, space group (P1) with lattice parameters a = 7.592(2) ?, b = 7.595(2) ?, c = 11.886 (3) ?, V = 574(3) ?³, Mr = 352.33, Dc = 1.478 g/cm³, μ(MoKα) = 0.33 mm⁻¹, F(000) = 262, Z = 1, the final R = 0.090 and wR = 0.209 for 2,315 observed reflections (I > 2σ(I)). The crystal structure is formed by two benzimidazole molecules which are linked by a water molecule. A UV–Vis spectrophotometer and a fluorophotometer were used to detect the benzimizadole-hydrate crystal transformation process, which shows that benzimidazole-hydrate can only be formed from Schiff base effectively when ortho-hydroxyl group does not exist in benzaldehyde. The synthesis mechanism was also discussed. Compared with its Schiff base, benzimidazole-hydrate displays stronger fluorescence.