Fast Electrochemical Characterization of Historical Glasses Using Carbon Screen‐Printed Electrodes and Ultrasonic Assisted Sampling

A new method for lead oxide (PbO) analysis in glasses, using a carbon screen printed electrode (SPE) is proposed. A suspension of the powdered glass sample in nitric acid is prepared using an ultrasonic probe, 100 µL of slurry are deposited on the SPE and the voltammetric measurement is carried out. Structural information of PbO in the glass matrix is obtained by CV. Lead quantification is performed by DPV. In the best conditions a LOD of 2.30 wt% of PbO was obtained. The method has been applied with good results in the analysis of historical glasses samples.     

超声搅拌化学浴沉积法制备大颗粒和致密的CdS薄膜

采用超声搅拌化学浴法(UCBD)在SnO2:F透明导电玻璃衬底上制备了CdS薄膜.研究了退火和CdCl2处理对UCBD-CdS薄膜的表面形貌、晶体结构和直接带隙的影响,比较了沉积时间对UCBD-CdS薄膜中CdS聚集体颗粒大小和堆积致密性的影响.结果表明,CdCl2处理可使CdS聚集体中的小颗粒重新熔合在一起,但CdS聚集体的大小并没有改变.在UCBD-CdS薄膜的沉积过程中,CdS薄膜的横向和纵向生长速率之比会随着沉积时间的不同而改变,且沉积时间是获得大颗粒的CdS聚集体和致密的UCBD-CdS薄膜的重要影响因素.当沉积时间为40min时,获得的UCBD-CdS薄膜较致密,CdS聚集体的大小为180nm,膜厚为80.8nm,适合作为薄膜太阳电池的窗口层.     

Ultrasound-promoted,rapid, green,one-pot synthesis of 2′-aminobenzothiazolomethylnaphthols via a multi-component reaction,catalyzed by heteropolyacid in aqueous media

A one-pot, three-component condensation reaction of 2-aminobenzothiazole, 2-naphthol and appropriate aldehydes catalyzed by heteropolyacid (HPA) in an aqueous medium afforded the Mannich adduct 2′-aminobenzothiazolomethylnaphthols at 45 °C under ultrasound irradiation. This method provides several advantages such as simple work-up procedure, short reaction time and high yields.     

正交设计-紫外分光光度法测定青蒿中的青蒿素

以干青蒿叶为原料,考察石油醚萃取青蒿素的工艺条件,如温度、时间、溶剂量及超声功率等因素,正交法确定了最佳萃取工艺条件为温度40℃,超声功率90W,时间20min（两次）,液固比120∶1（mL.g-1）。紫外分光光度法直接测定不同产地青蒿中青蒿素的含量,结果表明：用超声波强化石油醚萃取青蒿素与常规浸泡法石油醚萃取比较,用超声波可以大大缩短萃取时间,提高了萃取率。     

船用超声液位传感器的分析与设计

介绍了一种船用某型超声液位传感器的基本结构和工作原理。在对脉冲式超声探头的轴向声压分布特点及其声透射强度分析研究的基础上,给出了该传感器的超声信号发射端与接收端之间距离d和压电晶片保护膜的壁厚δ值的确定方法。最后设计了一套超声液位传感器性能测试实验平台,对上述理论研究结论进行了实验验证。     

Long distance laser ultrasonic propagation imaging system for damage visualization

Wind turbine blade failure is the most prominent and common type of damage occurring in operating wind turbine systems. Conventional nondestructive testing systems are not available for in situ wind turbine blades. We propose a portable long distance ultrasonic propagation imaging (LUPI) system that uses a laser beam targeting and scanning system to excite, from a long distance, acoustic emission sensors installed in the blade. An examination of the beam collimation effect using geometric parameters of a commercial 2 MW wind turbine provided Lamb wave amplitude increases of 41.5 and 23.1 dB at a distance of 40 m for symmetrical and asymmetrical modes, respectively, in a 2 mm-thick stainless steel plate. With this improvement in signal-to-noise ratio, a feasibility study of damage detection was conducted with a 5 mm-thick composite leading edge specimen. To develop a reliable damage evaluation system, the excitation/sensing technology and the associated damage visualization algorithm are equally important. Hence, our results provide a new platform based on anomalous wave propagation imaging (AWPI) methods with adjacent wave subtraction, reference wave subtraction, reference image subtraction, and the variable time window amplitude mapping method. The advantages and disadvantages of AWPI algorithms are reported in terms of reference data requirements, signal-to-noise ratios, and damage evaluation accuracy. The compactness and portability of the proposed UPI system are also important for in-field applications at wind farms.     

The effects of ultrasound frequency and power on the activation energy in Si-KOH reaction system

The activation energy is the minimum amount of energy required to initiate a reaction. It is one of the important indexes for appraising a reaction. The chemical reaction rate is closely related to the value of activation energy, and reducing activation energy is propitious to promoting a chemical reaction. In the present paper, the relationship between the activation energy in Si-KOH reaction system and the ultrasound frequency and power has been discussed for the first time. The range of ultrasound frequency and power is 40-100kHz （interval by 20kHz） and 10-50W （interval by 10W）, respectively. The experimental clata indicate that the activation energy decreases with the increasing ultrasound power. Comparing with the activation energy without ultrasound irradiation, the results in our paper indicate that ultrasound irradiation could reduce the activation energy in Si-KOH reaction system and increase the reaction rate.     

Ultrasonic nebulization extraction coupled with headspace single drop microextraction and gas chromatography-mass spectrometry for analysis of the essential oil in Cuminum cyminum L.

A novel method for analysis of essential oil in Cuminum cyminum L. using simultaneous ultrasonic nebulization extraction and headspace single drop microextraction (UNE-HS-SDME) followed by gas chromatography-mass spectrometry was developed. Experimental parameters, including the kind of suspended solvent, microdrop volume, sample amount, extraction time, enrichment time and salt concentration were examined and optimized. Compared with hydrodistillation (HD), UNE-HS-SDME provides the advantages of a small amount of sample (50 mg), time-saving (20 min), simplicity, cheapness and low toxicity. In addition, UNE-HS-SDME also provided higher enrichment efficiency and sensitivity compared with stirring extraction (SE)-HS-SDME, ultrasonic assistant extraction (UAE) and UNE. Some constituents in the essential oil, were identified and the detection limits for β-pinene, p-cymene and γ-terpinene range from 6.67 pL L⁻¹ to 14.8 pL L⁻¹. The results indicated that the UNE-HS-SDME is simple and highly efficient extraction and enrichment technique.     

Determination of Prometryne in water and soil by HPLC-UV using cloud-point extraction

A CPE-HPLC (UV) method has been developed for the determination of Prometryne. In this method, non-ionic surfactant Triton X-114 was first used to extract and pre-concentrate Prometryne from water and soil samples. The separation and determination of Prometryne were then carried out in an HPLC-UV system with isocratic elution using a detector set at 254 nm wavelength. The parameters and variables that affected the extraction were also investigated and the optimal conditions were found to be 0.5% of Triton X-114 (w/v), 3% of NaCl (w/v) and heat-assisted at 50 °C for 30 min. Using these conditions, the recovery rates of Prometryne ranged from 92.84% to 99.23% in water and 85.48% to 93.67% in soil, respectively, with all the relative standard deviations less than 3.05%. Limit of detection (LOD) and limit of quantification (LOQ) were 3.5 μg L⁻¹ and 11.0 μg L⁻¹ in water and 4.0 μg kg⁻¹ and 13.0 μg kg⁻¹ in soil, respectively. Thus, we developed a method that has proven to be an efficient, green, rapid and inexpensive approach for extraction and determination of Prometryne from soil samples.     

Quantitative determination of 16 polycyclic aromatic hydrocarbons in soil samples using solid‐phase microextraction

A method for the determination of polycyclic aromatic hydrocarbons (PAHs) in soil samples using ultrasonic‐assisted extraction with internal surrogates combined with solid‐phase microextraction and GC‐MS has been developed. Five kinds of commercial solid‐phase microextraction fibers, 100 μm PDMS, 30 μm PDMS, 65 μm PDMS/DVB, 50 μm DVB/CAR/PDMS and 85 μm PA, were compared to choose the optimal SPME fiber for extraction of PAHs. One hundred micrometers of PDMS fiber was found to be more suitable for the determination of PAHs due to its wider linear range, better repeatability, lower detection and more satisfactory efficacy than the other fibers. Under the recommended conditions, 100 μm PDMS fiber could provide low nanogram level detection limits with correlation coefficient greater than 0.98. The method was also applied to determine PAHs in a spiked soil sample, obtaining recoveries higher than 79.3%. A field study with naturally contaminated samples from local contaminated sites was carried out. The proposed method was found to be a reliable, inexpensive and simple preparation method for quantitative determination of 16 PAHs in soil samples.