光谱法研究纳米二氧化硅(SiO_2)催化超声波照射对牛血清白蛋白(BSA)的损伤

利用紫外-可见(Uv-Vis)光谱和荧光光谱研究了超声波照射激活纳米二氧化硅(SiO2)粒子对牛血清白蛋白(BSA)分子的损伤,并考查了超声波照射时间、纳米SiO2粉末加入量、溶液酸度和超声波照射功率等因素对BSA分子损伤程度的影响.结果表明,对于体系温度为(37.0±0.2)℃和浓度为1.0×10-5mol·-1的BSA溶液,UV-Vis光谱显示,随着超声波照射时间,纳米SiO2粉末加入量,溶液pH值和照射功率的增大呈现出越来越明显的增色效应.然而,BSA溶液的荧光光谱却随着上述因素的增大呈现出越来越明显的猝灭现象.此外,还初步探讨了超声波照射激活纳米siO2粒子对BSA分子损伤的机理,认为是声致发光或高热激发使纳米siO2粒子产生·OH自由基,进而损伤溶液中的BSA分子.这一研究结果对声催化方法应用于临床治疗肿瘤以及纳米药物的开发具有一定的指导意义.     

超声波对固定化酶活性的影响

本文介绍了超声波对固定化酶的影响，同时对作用过程中的影响因素进行了阐述，并探讨了超声波影响固定化酶的可能机理。     

岩石特性对超声波传播速度的影响

通过声速测定实验仪及数字示波器等装置测量了超声波在岩石中的传播速度,并对岩石成分、孔隙度、吸水量以及岩石温度等参数对超声波传播速度的影响进行了分析.结果表明,岩石孔隙度对超声波传播速度影响较大.同时,超声波传播速度随着岩石吸水量和环境温度的升高,传播速度呈现增大趋势.     

基于AVR单片机的超声波测距系统构建

为了提高超声波测距精度,构建了基于AVR单片机的测距及数据处理系统。分析了超声波测距的原理,以AVR单片机为处理器设计了超声波产生和发射电路、超声波接收和信号处理电路以及温度测量和补偿电路等。针对温度对超声波速度的影响,根据超声波速度与温度的关系,设计了超声波速度补偿算法。为了提高回波时间测量准确性,减小随机噪声及空气中其他杂散播干扰的影响,采用均值数字滤波方法,对计数时间进行处理。实测结果表明,在3cm~400cm范围内,超声波测距系统测量数据准确,最大误差为0.66cm。     

固体隔声层对超声波传播的影响实验研究

本文对测量固体隔声层对超声波传播发生影响的实验装置进行了介绍 ,并进行了实际测量 ,理论和实验结果相符较好     

超声波对木瓜蛋白酶催化活性影响的机理研究

木瓜蛋白酶经适当参数的超声波处理后酶活力提高。超声处理后酶的米氏常数Km变小,最大反应速率Vm也减小。超声处理后酶的紫外吸收光谱不变,荧光发射光谱也不改变,而差示光谱出现明显的正峰和负峰。研究结果表明,超声波处理后,木瓜蛋白酶的构型没有改变,而构象发生了变化。本文讨论了超声波影响木瓜蛋白酶活性的可能机理。     

超声波对西施舌面盘幼虫生长率及成活率的影响

摘要实验室内用静水实验方法研究超声波对西施舌面盘幼虫生长速率、摄食率及成活率的影响。结果表明适宜条件超声辐射可提高面盘幼虫的生长速率和摄食率。在电功率为80w、频率20．4kHz条件下，超声辐射30s，幼虫日平均生长速率最快达13．67％，比对照组11．45％快2．22％。重复的超声辐射对幼虫的生长速率产生明显影响，第一次辐射后第1天各实验组面盘幼虫的生长速率都比对照组大，而辐射时间为50s实验组第1天生长速率最大达18．95％，比对照组10．23％提高8．72％。多次辐射幼虫生长速率明显减慢。     

强化管型对超声波除垢影响的实验研究

结垢问题长久存在于电力、化工、石油等领域,将超声波应用在除垢上具有十分显著的优势。为研究不同管道内结垢和超声波除垢情况,本文采用实验方法,针对三种不同形状(圆管、波纹管和横纹管)管道进行结垢和超声波除垢研究。结果表明,波纹管内结垢量较其它两根管较少,而横纹管的超声波除垢效率最高。由此,可为工程实际中特殊管道的除垢及传统圆管可否进行管型改进提供一定的理论依据。     

变压吸附系统气流分布器结构对分配性能的影响

建立了变压吸附系统分布器结构的数学模型,并对吸附柱入口的速度场分布进行了研究,计算结果表明:目前工业吸附柱入口物流分配存在严重的不均匀性,而且Reynolds越大,物流分配越不均匀。在此基础上,对多种不同型式分布器结构进行了数值模拟,计算结果表明分布器结构是影响分配效果的主要因素,吸附柱气体分布器结构优化设计对改进吸附效果具有重要的意义。     

不同岩石物性对超声波传播的影响

通过测量超声波在岩石样品中的传播速度,研究了岩石的结构构造、密度、孔隙度和弹性模量等物理特性对超声波传播的影响.实验结果表明:岩石的结构构造、密度和孔隙度对超声波波速影响较大,而动态弹性模量与超声波速度的关系则反应了岩石可承受形变的能力,超声波在岩石中的传播速度受多种岩石物性的影响,但也具有一定的传播规律.     

超声波对多聚糖结构特性的影响

本文以灵芝为主要对象研究了多糖结构和微晶束结构及其稳定性和抗解性，通过对加超声能量场，对结晶结构施加强烈的机构冲击，使稳定性和抗解性消弱。     

Spectroscopic analyses on interaction of bovine serum albumin (BSA) with toluidine blue (TB) and its sonodynamic damage under ultrasonic irradiation

In this paper, the toluidine blue (TB) with tricyclic quinone imide plane structure is used as sonosensitizer to study the interaction and sonodynamic damage to bovine serum albumin (BSA) by UV-vis and fluorescence spectroscopy. The results show that the TB can bind to BSA molecules, obviously, and the synergetic effects of TB and ultrasonic irradiation can efficiently damage the BSA molecules. Otherwise, some influencing factors such as ultrasonic irradiation time, TB concentration, pH value and ionic strength on the damage of BSA molecules were also considered by the numbers. Synchronous fluorescence spectroscopy indicates that the tyrosine (Tyr) residues of BSA molecules are damaged more seriously than the tryptophan (Trp) residues under ultrasonic irradiation.     

An ammonium sulfate/ethanol aqueous two-phase system combined with ultrasonication for the separation and purification of lithospermic acid B from Salvia miltiorrhiza Bunge

We studied the effect of ultrasonication extraction technology combined with ammonium sulfate/ethanol aqueous two-phase system (ATPS) for the separation of lithospermic acid B (LAB) from Salvia miltiorrhiza Bunge. According to the literature and preliminary studies, ammonium sulfate concentration, ethanol concentration, pH, ultrasonication power, ultrasonication time and the ratio of solvent-to-solid were investigated using a single factor design to identify the factors affecting separation. Taking into consideration a simultaneous increase in LAB recovery (R (%)) and partition coefficient (K), the best performance of the ATPS was obtained at 25 °C and pH 2 using ammonium sulfate 22% (w/w) and ethanol 30% (w/w). To keep the solvent-to-solid ratio at 10, response surface methodology was used to find the optimal ultrasonication power and ultrasonication time. Quadratic models were predicted for LAB yield in the upper phase. Optimal conditions of 572.1 W ultrasonication power and 42.2 min produced a maximum yield of LAB of 42.16 mg g⁻¹ sample. There was no obvious degradation of LAB with ultrasound under the applied conditions, and the experimental yield of LAB was 42.49 mg g⁻¹ sample and the purity was 55.28% (w/w), which was much higher than that obtained using conventional extraction. The present study demonstrated that ultrasound coupled with aqueous two-phase systems is very efficient tool for the extraction and purification of LAB from Salvia miltiorrhiza Bunge.     

Effect of wood properties on within-tree variation in ultrasonic wave velocity in softwood

The radial variations in the velocity of longitudinal waves propagating through Japanese cedar and Japanese cypress were experimentally investigated. In addition, the tracheid length (TL), microfibril angle (MFA), air-dried density (AD), and moisture content (MC) were measured in order to determine the effect of wood properties on velocity variations within the wood trunk. For both species, the longitudinal wave velocities measured in the longitudinal direction (V_L) exhibited minimum values near the pith. For Japanese cedar, V_L increased from 3600 m/s toward the bark and soon attained a constant value (=4500 m/s). On the other hand, for Japanese cypress, V_L kept increasing from 4000 m/s near the pith to 4800 m/s at the bark. These radial variations in V_L coincided with those in the tracheid length. V_L exhibited strong correlations with TL and MFA with a significant level of (p < 0.01). These findings suggest that the TL and MFA greatly affect the radial variation in the ultrasonic wave velocity in softwood.     

圆管超声导波频散与多模态特性研究*

超声导波检测技术作为一种新兴的无损检测技术广泛应用于圆管类结构。为选择合适于不同缺陷检测的导波模态,推导分析了圆管导波传播的运动方程和频散方程;利用数值计算的方法得到了超声导波在圆管中传播的频散曲线和各模态沿壁厚方向的位移分布图,分析得出各个模态对不同缺陷的敏感程度;以一种特定的圆管为例,建立圆管缺陷有限元模型,对不同类型圆管缺陷对导波传播特性的影响进行仿真计算。结果表明,纵向模态对周向缺陷比较敏感,而扭转模态则对轴向缺陷更敏感,仿真结果与理论分析结果相吻合,为圆管缺陷检测的超声导波模态选择提供了理论依据。     

Spectroscopic investigation on the sonodynamic activity of amsacrine (AMSA) to bovine serum albumin (BSA) damage

The sonodynamic damage of bovine serum albumin (BSA) under ultrasonic irradiation in the presence of amsacrine (AMSA) was studied by hyperchromic effect of UV-vis spectra and quenching effect of intrinsic fluorescence. In addition, several influencing factors such as ultrasonic irradiation time, AMSA concentration, system acidity and ionic strength about the damage of BSA molecules were reviewed. The results showed that the damage degree was obviously enhanced with the increase of ultrasonic irradiation time and AMSA concentration, but it was only slightly increased with the increase of solution pH value and ionic strength. Furthermore, the binding and damaging sites to BSA molecules were estimated by synchronous fluorescence spectra. The different chances to damage tryptophan (Trp) and tyrosine (Tyr) residues were found through the ratios of synchronous fluorescence quenching (R_SFQ). At last, the generation of reactive oxygen species (ROS) in sonodynamic process was estimated by the method of oxidation-extraction Spectrometry (OES). And then, several radical scavengers were used to determine the kind of ROS, which includes singlet oxygen (¹O₂) and hydroxyl radicals (·OH). Perhaps, the result would bring a certain guiding significance to use sonosensitive drugs in the fields of tumor treatment.     

Comparative study of ultrasonic pretreatment and ultrasound assisted three phase partitioning for extraction of custard apple seed oil

Custard apple seed oil is a marketable product extracted from custard apple seed which is a potential agriculture waste. The present work aims to elucidate simultaneous extraction of the custard apple seed oil and proteins using three phase partitioning (TPP). The efficient oil extraction was executed by optimization of parameters including time, slurry ratio, salt concentration, and slurry to t-butanol ratio. Additionally, the application of ultrasound as process intensification tool for TPP was studied that reduces the time of conventional TPP and increases the yield by 2.53%. The work also comprises a comparative study of two modes of ultrasound application, namely ultrasound pre-treatment and simultaneous ultrasound assisted TPP. This work proves ultrasonic pre-treatment followed by TPP as a superior mode of ultrasound application that attributes 33.6 ± 0.56% (w/w) oil extraction with optimized pre-treatment time of 150 s, 30 W ultrasound power and 75% duty cycle. Extraction kinetics studied for conventional, Ultrasound assisted Three Phase Partitioning (UTPP), and Ultrasound Pre-treatment assisted Three Phase Partitioning (UPTPP) were observed to fit Peleg’s model.     

Effect of the ultrasonic standing wave frequency on the attractive mineralization for fine coal particle flotation

Froth flotation for mineral beneficiation is one of the most important separation techniques; however, it has several challenges for processing fine and ultrafine particles. Attractive mineralization between particles and bubbles by ultrasonic standing wave (USW) is a novel and high-efficiency method that could assist fine particle flotation. Frequency is an important ultrasound parameter, whose effectiveness mechanisms on the attractive mineralization did not compressively address. This study explored the effect of the USW field with various frequencies on the fine coal flotation for filling this gap. Herein, a high-speed camera and a focused beam reflectance measurement (FBRM) were used to analyze three sub-processes of the attractive mineralization, including the microbubbles’ formation, the conventional flotation bubbles (CFBs)’ dispersion, and the particles’ movement. It was found that the maximum flotation metallurgical responses were obtained under the highest examined USW frequency (600 kHz). However, the flotation outcomes by a low USW frequency (50 kHz) were even lower than the conventional flotation tests. Observation and theoretical calculation results revealed these results were originated from the influence of frequency on the carrier bubbles’ formation and the action of the secondary acoustic force during USW-assisted flotation. These outcomes demonstrated that frequency is a key factor determining the success of attractive mineralization for fine particles’ flotation.     

超声测断面形状误差分析及测试方法探讨

本文对超声波斜入射情况下存在的测距误差进行了分析，给出了数学修正的公式，并通过实验进行了验证，对测量不同形状空间的测试方法了探讨。本文的讨论对提高测试精度和选择工程测试方案有参考意义。