Synthesis,crystal structure and Hirshfeld surface analysis of a new 0D nanostructured [{Ar-Cl)tetra-azo-S}2Hg] coordination supramolecular compound derived from phenyl isothiocyanate ligand

Abstract

Nanoparticles of a new mercury(II) coordination supramolecular compound (CSC), [{(Ar-Cl)tetra-azo-S}₂Hg] (1), were synthesized using a sonochemical process and characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and elemental analyses (EA). The single crystal X-ray data of 1 revealed that the Hg ion was two-coordinate. Also, Hirshfeld surface analysis of 1 showed the effective role of interactions related to nitrogen atoms in stabilization of the supramolecular structure. The role of ultrasonic power, sonicating time and temperature on the size and morphology of the nano-structured compound obtained from 1 were investigated. The results indicated that increasing temperature and sonication power and decreasing sonication time led to reducing the particle size.     

Determination of Benzo(a)Pyrene and other Polynuclear Aromatic Hydrocarbons in Airborne Particulate Material by Ultrasonic Extraction and Reverse Phase High Pressure Liquid Chromatography

Abstract

Ultrasonic extraction of airborne particulate material on Hi-Vol filters is described. Almost all of the polar compounds are removed during the extraction by adsorption on the surface of the shredded glass fibers and controlled pore glass powder (CPG). The non-polar polynuclear aromatic hydrocarbons (PAH) in the extract are separated at room temperature by high pressure liquid chromatography (HPLC) on reverse phase Vydac using acetonitrile:water (70:30 v/v) as the chromatographic solvent. There is baseline separation of benzo(a)pyrene (BaP), benzo(k)fluoranthene (BkFt) and of benzo(e)pyrene (BeP), benzo(b)fluoranthene and perylene, the latter three present in one band. Extracts of airborne particulates show the same peaks. BaP elutes in approximately 14 minutes. Precision and accuracy measurements indicate full recovery of PAH and good extraction reproducibility. The detection limit of BaP at F 290/389 is less than 10 pg. Total analysis time is approximately 1 1/2 hr, most of which is waiting time.     

ULTRASONIC RELAXATION KINETICS OF PLANAR:OCTAHEDRAL EQUILIBRIA OF A NICKEL MACROCYCLIC COMPLEX

Abstract

The equilibrium between the diamagnetic, planar nickel(II) macrocyclic complex known as NiCR²⁺(CR is 2,12-dimethyl-3,7,11,17-tetraazabicyclo[11.3.1]heptadeca-1(17),2, 11,13,15pentaene) and its paramagnetic, six-coordinate dimethanol adduct has been examined in methanol solution as the tetrafluoroborate salt. From the temperature dependence of the electronic absorption spectrum, thermodynamic parameters of ΔH°₄₆ = ?4.35 kcal mol^?1 and ΔS°₄₆ = ?8.72 cal deg^?1 mol^?1 were determined. From the excess ultrasonic absorption a relaxation frequency of 15 MHz was observed from which rate constants of k₄₆ of 8.6 × 10⁷ s^?1 and k₆₄ of 7.9 × 10⁶ s^?1 were calculated. The rate constant k₄₆ is nearly the same as the rate constant for solvent exchange which had previously been determined by NMR. This implies that the solvent exchange is effected by the octahedral-planar equilibrium and that a two-step mechanism with a five-coordinate intermediate can be eliminated.     

超声提取-毛细管气相色谱法检测酱腌菜中对羟基苯甲酸酯

采用超声提取法提取酱腌菜中的对羟基苯甲酸甲酯、对羟基苯甲酸乙酯及对羟基苯甲酸丙酯,在SE30毛细管柱(33 m×0.53 mm,2.65μm)上得到了良好分离。对羟基苯甲酸甲酯、对羟基苯甲酸乙酯及对羟基苯甲酸丙酯在0～750μg/mL浓度范围内与色谱峰面积呈良好的线性关系,相关系数为0.9999。对羟基苯甲酸甲酯、对羟基苯甲酸乙酯、对羟基苯甲酸丙酯的检出限分别为0.1,0.1,0.2μg/mL,测定结果的相对标准偏差小于3.6%(n=11),平均回收率为84.5%～97.1%。     

超声波辅助萃取-气相色谱法同时测定蔬菜中5种有机磷农药残留

建立超声波辅助萃取-气相色谱法同时分离测定蔬菜中5种有机磷农药残留量的：弓．法。实验结果表明,采用超声波加速提取有机磷农药残留,样品提取效果好,干扰物少,检测快速;在DB-1701色谱柱中,供试的5种有机磷农药分离良好;以FPD为检测器,选择性较好。方法的检出限为0．004-0．01μg／mL,5种农药在2个添加水平下的回收率为78．9％-105．9％,测定结果的相对标准偏差为2．6％-7．6％（n=6）。该方法具有测定有机磷农药种类多、快速等优点,能满足农药多残留分析的要求。     

精制废木屑热解油/柴油新型混合燃料制备实验研究

为提高废木屑热解油品质,使其能够作为发动机燃料使用,提出了一条新的热解油提质路线。首先将热解原油进行基于组分分离的乙醚萃取和化学催化相结合的精制过程,得到精制热解油;其次,利用超声反应器制备了精制热解油/柴油新型混合燃料,以单位体积柴油所溶解的精制油的体积定为S值,作为判断乳化效果的准则,考察了不同的影响因素对S值的影响。研究结果表明,乳化剂添加量对S值影响较大,在V_{精制生物油}:V_柴油:V_乳化剂=10:30:5条件下,存在最佳的乳化超声操作条件:超声时间、超声电功率、乳化温度分别为20 min、540 W、50℃。制备了不同S值的乳化燃料,通过对燃料物理指标的分析发现,该燃料性质稳定、燃烧性能优良,有望成为柴油的替代产品。     

超声马达梯度涂层摩擦材料研究

超声马达摩擦材料应同时具有良好的摩擦学特性和一定的接触变形要求,目前所用单一均质结构摩擦材料较难满足这一要求,需要研制新型摩擦材料.本文从摩擦学的减摩结构模型反推出一种增摩结构模型,针对超声马达对摩擦材料的要求,提出梯度涂层摩擦材料的设计思想,采用表面黏涂法研制了一种具有梯度结构的涂层摩擦材料.利用超声马达模拟试验装置考察了涂层厚度对超声马达性能的影响,初步验证了模型的正确性.在本文的试验条件下,当涂层材料表层厚度为1mm,底层厚度为0.7mm左右时,超声马达具有较好的性能.与其它种类的摩擦材料相比较,梯度涂层摩擦材料可以满足超声马达的使用要求,可望提升超声马达的性能,具有良好的发展前景.     

Large frequency bands viscoelastic properties of honey

Honey is a viscoelastic material which presents a crystallization phase transition at low temperatures. This phase transition limits the studies of dynamic behavior at high frequencies from the classical rheometry using time–temperature superposition (TTS). In order to characterize the viscoelastic properties of honey at high frequencies, we have developed a multiple ultrasonic reflection device (MUR). The viscoelastic properties of honey were measured by MUR and classical rheometry at high and low frequencies, respectively, between 13.1 and 31.3 °$°$C. Matching both results, we built the master curve over a frequency range covering nine decades, from which we determined the main rheological parameters of honey. Finally, from an inverse approach, we extracted from this master curve, the acoustical parameters for frequencies inaccessible by the ultrasonic methods.     

ACOUSTICAL TRANSMISSION LINE MODEL FOR ULTRASONIC TRANSDUCERS FOR WIDE-BANDWIDTH APPLICATION

An improved model for ultrasonic transducers is proposed.By considering only the first symmetric mode,each layer is represented as an acoustical transmission line in modeling of bulk wave transducers.In imaging applications,wide bandwidth and short time duration are required.The approach we have used consists of impedance matching the front face of the piezoelectric transducer to the propagating medium with a quarter wavelength impedance matching layer and inserting an unmatching quarter wavelength acoustical layer between the rear face and backing material.A heavy backing would degrade the wide-band phenomena,but show a time duration shorter than 0.5 μs for imaging applications.PSPICE code of the controlled source model is implemented to precisely predict the performance of the matched transducers such as impedance,insertion loss,bandwidth and duration of the impulse response.Good agreement between the simulation and experimental results has been achieved.     

超声降解处理水体污染物的研究状况与发展

利用超声产生的空化效应来降解水体中的污染物,是近几年来国外研究者关注的热点领域之一。文章就超声在污染水体降解的原理、理论、降解效果以及主要的影响因素作扼要的综述介绍,对存在的问题和发展的趋势提出见解和看法。