正交试验优化高浓度酒精发酵促进剂配方的研究

本文优化了高浓度酒精发酵促进剂的最佳配方,以酒精浓度为考察指标,研究了酵母浸粉、蛋白酶与无机盐三成分促进剂对酒精发酵的影响,并在单因素的基础上通过正交试验对其进行了优化。结果表明:发酵促进剂最佳配方为酵母浸粉0.2%,蛋白酶量10U/g,MgSO41.0%,KH2PO42.5%,此时酒精浓度为15.2%。     

荸荠多糖的超声波辅助提取工艺

为提高荸荠多糖的得率,采用超声波辅助法提取荸荠多糖。通过单因素试验研究超声波功率、料液比、提取温度、超声处理时间、乙醇浓度对荸荠多糖得率的影响,确定荸荠多糖的最佳提取工艺。单因素试验结果表明,在本试验条件下,超声波功率为300W、料液比1：10、提取温度为50℃、超声时间25min时荸荠多糖得率最高。     

超声波-双水相萃取印楝素工艺的研究

采用超声波耦合乙醇-硫酸钠双水相提取印楝素,将超声功率密度,超声时间,超声辐射方式作为其影响因素,并分别进行单因素实验和正交实验对其进行研究,最终确定了超声波双水相提取印楝素的最佳工艺。最佳工艺条件为:功率密度为2.4 w/cm2,时间为30 min,辐射方式为7s/10s。并且影响印楝素超声提取率的主次因素为功率密度辐射方式超声时间,最优条件下印楝素的提取率为0.3200%。     

布朗李果酒发酵工艺研究

目的为了优化布朗李果酒的最佳发酵工艺。方法以布朗李为原料,选取酵母接种量、发酵温度、初始含糖量、二氧化硫添加量为影响因子,以酒精度为考察指标,在单因素试验的基础上对布朗李果酒的发酵工艺进行正交优化。结果得到了布朗李果酒发酵的最优工艺参数,酵母接种量(体积分数)为5%,发酵温度为26℃,初始含糖量(质量分数)为24%、二氧化硫添加量为80 mg/L。在此条件下发酵7 d的果酒酒精度(体积分数)为11.9%。结论该工艺生产的布朗李果酒酒精度高,原料发酵充分,利用率高。     

竹叶中叶绿素的提取工艺及其功能性应用研究

以毛竹叶为原料,使用丙酮作为提取剂,通过振荡水浴预处理,辅助超声波作用提取毛竹叶叶绿素,并且对叶绿素提取效率进行测试。对主要参数(如振荡时间、超声时间、超声功率等)设计了单因素试验。得出较适宜的提取工艺为:振荡水浴处理时间10min,超声波清洗器处理时间20min,超声功率140W,在此条件下,叶绿素提取效率较高,提取含量达到2.39mg/g。同时,采用不同方法制备聚乙烯醇(PVA)/叶绿素膜,通过荧光显微镜、扫描电子显微镜(SEM)对制得PVA/叶绿素膜进行观测。结果表明,PVA/叶绿素膜保持叶绿素的荧光特性;在纺丝工艺中,叶绿素吸附在纤维表面形成PVA/叶绿素膜。     

超声波辅助提取花生中白藜芦醇的工艺研究

本实验设计超声波辅助有机溶剂法提取花生中的白藜芦醇。通过超声波正交试验对花生红衣中的白藜芦醇含量进行测定,确定白藜芦醇的优化提取工艺。实验结果表明,超声波辅助提取的工艺条件为:料液比为1∶10(g/m L),超声时间为30min,乙醇浓度为60%。此条件下,白藜芦醇的回收率可高达106%。通过该工艺,白藜芦醇在花生根中提取的含量最高,为139.01mg/kg,红衣中为7.57mg/kg。     

酵母和乳酸菌共同发酵对面包品质的影响

本文论述了乳酸菌和酵母共同发酵对面包品质的影响。结果表明,乳酸菌和酵母共同作用,比单一加酵母所制得的面包品质好。通过正交试验确定了乳酸菌用量为4%、糖量8%、第一次发酵时间为5h,能增大甜面包的体积、改善风味和内部组织结构。     

酵母和乳酸菌共同发酵对面包品质的影响

本文论述了乳酸菌和酵母共同发酵对面包品质的影响。结果表明，乳酸菌和酵母共同作用，比单一加酵母所制得的面包品质好。通过正交试验确定了乳酸菌用量为4％、糖量8％、第一次发酵时间为5h，能增大甜面包的体积、改善风味和内部组织结构。     

鸡腿蘑菌丝体的液体培养试验

通过对液体发酵培养的试验,探索出了液体发酵最适合的培养条件,通风量研究试验,接种量研究试验和茵丝体发酵周期对比等,提供为今后人工栽培了科学依据。     

枸杞色素的闪式提取和超声-微波协同提取工艺

目的 以枸杞为原料,比较不同提取工艺对枸杞色素吸光值的影响,以确定枸杞色素的最佳提取工艺.方法 通过单因素试验和响应面法对枸杞色素的闪式提取和超声-微波协同提取工艺进行研究.结果 闪式提取枸杞色素的最佳工艺条件为料液比(g/mL)1︰13,提取电压113 V,提取时间112 s,该条件下枸杞色素吸光度为0.457;超声-微波协同提取枸杞色素的最佳工艺条件为料液比(g/mL)1︰16,微波功率613 W,提取温度55℃,提取时间32 min,该条件下枸杞色素吸光度为0.502.结论 对2种提取方法在最佳工艺条件下进行比较,超声-微波协同提取法提取枸杞色素的效果优于闪式提取法.     

Preparation of bioelectret collagen and its influence on cell culture in vitro

Collagen extracted from pigskin was corona-charged negatively by a specifically designed device. Different charging voltages, temperatures and times were applied to prepare collagen bioelectret. The decline of the surface potential of the bioelectret under different treatment was then determined. The data showed that the surface potential was markedly varied with the charging conditions. The optimal values of three parameters for charging collagen coatings were defined as follows: voltage, 8 KV; temperature, 40^°C; time, 25 min. Treatment of the bioelectret with distillated water, or saline solution (0.9%) or culture medium induced a sharp decrease of the surface potential. In addition, we investigated the effects of the charged collagen on cell growth and intracellular calcium level of three types of cultured mammalian cell lines, including Chinese hamster ovary CHO cells, human cervix uteri tumor HeLa cells and human promyelocytic HL-60 cells. Cell growth and the intracellular calcium level were determined by MTT reagent-based assay and a fluorescent probe Fura-2, respectively. The results showed that negatively charged collagen stimulated the growth of CHO or HL-60 cell line but inhibited the growth of HeLa cell line. Furthermore, after attaching to the charged collagen, the intracellular calcium level of CHO cells increased, while that of HeLa cells decreased. Thus we proposed for the first time that collagen bioelectret could differentially modulate the growth of different cells, by an unknown mechanism that probably involves a role of intracellular calcium.     

Enzymatic probe sonication: enhancement of protease-catalyzed hydrolysis of selenium bound to proteins in yeast

This paper describes the dramatic activity enhancement of two proteolytic enzymes (protease XIV and subtilisin) when treated with an ultrasonic probe and their application to total Se determination and Se speciation in biological samples. Total Se extraction from enriched yeast is performed with 10 mg of yeast plus 1 mg of protease with a sonication time of 5 s, whereas 30 s is needed for extracting selenomethionine. In both cases, aqueous media was used. This spectacular finding is important because the enzymatic procedure usually requires a long treatment period at 37 degrees C. In addition to this major advantage, no control temperature is needed and the risk of species interconversion is drastically reduced or inhibited (the same Se species were detected after different sonication times). Moreover, the extraction is performed in water, minimizing contamination risk and without further pH adjustment. The new sample treatment proposed has been successfully applied to selenium speciation in yeast using chromatographic separation (HPLC) coupled to inductively coupled plasma-mass spectrometry.     

Ultrasonic wave field effects on hydrogen production by water electrolysis

In this paper, Electrochemical impedance spectroscopy (EIS) was used to examine polarization impedance phenomena in ultrasonic water electrolysis. The method has been used previously for electrochemical analysis of fuel cells, corrosion, electroplating, etc. However, the EIS method and curvilinear regression have never been used before to analyze the electrochemical reactions which take place during water electrolysis. This study found that when a 2?V potential was applied, the ultrasonic wave field improved activity impedances and concentration impedances and accelerated the rising of hydrogen bubbles during water electrolysis. Ultrasonic power, electrode gap, and electrolyte concentration were the key parameters that affected water electrolysis. At normal temperature, when the electrode gap was 2?mm, the potential 4?V, and electrolyte concentration 40 wt%, the difference in current density between electrolysis without ultrasonic power and electrolysis with ultrasonic power of 225?W was 240?mA/cm². Deducting the power needed for the ultrasonic wave showed an power savings of 3.5?kW and an economical power efficiency of 15%.     

Continuous spore disruption using radially focused, high-frequency ultrasound

We report on the development of a novel, continuous-flow, radially focused ultrasonic disruptor capable of lysing Bacillus spores in the absence of added chemical denaturants, enzymes, or microparticles. Greater than 99% disruption was achieved for Bacillus globigii spores and Escherichia coli and Bacillus subtilis vegetative cells with sample residence times of 62, 12, and 12 s, respectively. Microscopic and SEM images indicated that at equivalent power levels, the incidence of cell death or loss of viability typically exceeded the efficiency of (visible) cell lysis. However, semiquantitative PCR showed up to a 1,000-fold increase in intracellular DNA availability from ultrasonically disrupted spores, and liberated DNA was intact and available for subsequent detection.     

High Strain Rate Response of Sandwich Composites with Nanophased Cores

Polyurethane foam materials have been used as core materials in a sandwich construction with S2-Glass/SC-15 facings. The foam material has been manufactured from liquid polymer precursors of polyurethane. The precursors are made of two components; part-A (diphenylmethane diisocyanate) and part-B (polyol). In one set of experiments, part-A was mixed with part-B to manufacture the foam. In another set, TiO₂ nanoparticles have been dispersed in part-A through ultrasonic cavitation technique. The loading of nanoparticles was 3% by weight of the total polymer precursor. The TiO₂ nanoparticles were spherical in shape, and were about 29 nm in diameter. Sonic cavitation was carried out with a vibrasound liquid processor at 20 kHz frequency with a power intensity of about 100 kW/m². The two categories of foams manufactured in this manner were termed as neat and nanophased. Sandwich composites were then fabricated using these two categories of core materials using a co-injection resin transfer molding (CIRTM) technique. Test samples extracted from the panel were subjected to quasi-static as well as high strain rate loadings. Rate of loading varied from 0.002 s^–1 to around 1300 s^–1. It has been observed that infusion of nanoparticles had a direct correlation with the cell geometry. The cell dimensions increased by about 46% with particle infusion suggesting that nanoparticles might have worked as catalysts during the foaming process. Correspondingly, enhancement in thermal properties was also noticed especially in the TGA experiments. There was also a significant improvement in mechanical properties due to nanoparticle infusion. Average increase in sandwich strength and energy absorption with nanophased cores was between 40–60% over their neat counterparts. Details of manufacturing and analyses of thermal and mechanical tests are presented in this paper.     

Densities, Excess Molar Volumes, Ultrasonic Speeds, and Isentropic Compressibilities of Hexan-1-ol with 1,2-Dichloroethane, 1,2-Dibromoethane, and 1,1,2,2-Tetrachloroethene at (293.15 and 298.15) K

Densities, ρ, and ultrasonic speeds, u, of binary mixtures of hexan-1-ol with 1,2-dichloroethane, 1,2-dibromoethane, and 1,1,2,2-tetrachloroethene have been measured over the entire range of composition at (293.15 and 298.15) K and atmospheric pressure. From these data, the excess molar volumes, V ^E, deviations of ultrasonic speed, u ^D, from the ultrasonic speed of an ideal mixture, excess molar isentropic compressibilities, ${\kappa_{S,{\rm m}}^{\rm E}}$ , intermolecular free lengths, L _f, mean molecular radii, r, and thermal expansion coefficients, α, have been calculated. The experimental ultrasonic speeds have been analyzed in terms of Nomoto’s, Van Dael’s ideal mixture, and Junjie relations; Jacobson’s free length and Schaaffs’ collision factor theories; and thermoacoustical parameters.     

Effects of nickel ethylenediamine complex on the preparation of Ni-B amorphous alloy catalyst with ultrasonic assistance

The Ni-B amorphous alloy catalysts with uniform particles were prepared by chemical reduction of nickel ethylenediamine complex by BH₄⁻ in aqueous solution with ultrasonic assistance. The catalysts were characterized by XRD, XPS, BET and H₂-TPD techniques. When used in the hydrogenation of glucose, the as-prepared Ni-B catalyst exhibited much higher activity than the conventional Ni-B catalysts obtained via direct reduction of Ni²⁺ by BH₄⁻ and Raney Ni. The higher activity could be attributed to both structure effect and electronic effect. The nickel ethylenediamine complex was found to retard and prevent an abrupt formation and agglomeration of Ni-B catalysts during the catalysts preparation. It was also found that the ultrasound plays a positive role.     

Freezing phenomena of supercooled water under impacts of ultrasonic waves

In order to clarify effects of ultrasonic waves on supercoold water, ultrasonic waves were applied to supercooled water. Frequency of the ultrasonic waves applied was 45 kHz, and the intensities of the waves were 0.13 and 0.28 W cm⁻², respectively. Four cases of experimental conditions were selected; a case of a free surface, a case of an oil-water surface, a case of a free surface with a dipped metal bar and a case of an oil–water surface with a dipped metal bar. For each experimental condition, water was cooled at a constant cooling rate and the ultrasonic wave was applied from underneath until the water in a test tube solidified. It was found that in the case of 0.28 W cm⁻², the ultrasonic wave had distinct effects on freezing of supercooled water for all experimental conditions. On the other hand, in the case of 0.13 W cm⁻², the ultrasonic wave had an effect on freezing of supercooled water only under existence of a free surface and a metal bar.     

Rapid synthesis of cryptomelane-type manganese oxide under ultrasonic process

Cryptomelane-type manganese oxide (OMS-2) was rapidly prepared under ultrasonic irradiation in short time. Characterization results using X-ray powder diffraction (XRD), surface area analyzer, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), oxygen temperature-programmed desorption (O₂-TPD) revealed that ultrasonic irradiation has tremendous effect on the surface area, morphology, surface defects, and redox properties of the OMS-2 materials. The OMS-2 prepared via ultrasonic irradiation shows nanoneedle morphology with smaller crystallite size, larger surface area (120.4 m²/g), more surface defects, and higher oxygen mobility, thus it demonstrates excellent activity in the catalytic combustion of dimethyl ether with a start-off temperature of 160 °C and a complete combustion temperature of 172 °C.