Study on Extraction of Oolong Tea Assisted by Ultrasonic Wave and 4C Technique and Its Application

[Objectives]The extraction conditions of formula oolong tea were investigated by an orthogonal experiment.[Methods]The technical conditions were optimized by the 4C method,and the application of formula oolong tea extract in cigarettes was studied.[Results]①In the experimental range,the best sensory evaluation effect of formula oolong tea extract was obtained with extraction conditions of 70%ethanol as extraction solvent,extraction time h,extraction temperature 25℃,and ultrasonic frequency 80 kHz,and follow-up low-temperature concentration,low-temperature sedimentation and low-temperature centrifugation.②The effects of different centrifugal speeds on the quality of formula oolong tea extract were explored.The formula oolong tea extract obtained under the conditions of 3000 r/min and centrifugal time of 10 min showed the best evaluation effect with soft and delicate smoke,rich smoke fragrance,good comfort and refreshing mouthfeel.③The effective aroma components in the formula oolong tea extract were qualitatively analyzed by GC-MS.[Conclusions]This study provides high-quality raw materials and a theoretical basis for the research of independent flavor blending in cigarette industry enterprises.

The application of laser reflective tomography in near-field measurements of ultrasonic transducers

With Laser Reflective Tomography（LRT）,the near fields of ultrasonic transducers were measured and analyzed.The principle of LRT measurement of ultrasonic field distribution was introduced and an experimental system was set up.Acoustic pressure of a multiple element piston transducer was measured by using of a laser vibrometer.Its distribution in amplitude and phase was obtained.The acoustic pressure in the same region was measured with a needle hydrophone to validate the LRT method.Furthermore,through reconstruction of acoustic fields,it indicated that LRT method is suitable for predicting the distribution on transducers＇surface and conditions of active elements.

Fibre Metallurgy Characteristic of Short Cast Iron Fibre and Its Applications for Diamond Wheel

A kind of diamond grinding wheel bonded by short cast iron fibres has been developed. ln comparison with high quality bronze bonded diamond grinding wheel. the new wheel was more suitable to grind hard and brittle materials like ceramics. For Si3N4, the grinding efficiency has been raised two times and the grinding ratio five times

Surface grain refinement mechanism of SMA490BW steel cross joints by ultrasonic impact treatment

Ultrasonic impact treatment (UIT) is a postweld technique for improving the fatigue strength of welded joints. This technique makes use of ultrasonic vibration to impact and plastically deform a weld toe and can achieve surface grain refinement of the weld toe, which is considered as the main reason for the improvement of fatigue strength. In this paper, the microstructure of the surface of a treated weld toe was observed by metallographic microscopy and transmission electron microscopy (TEM). The results show that UIT could produce severe plastic deformation on the surface layer of the weld toe and the maximum depth of plastic deformation extended to approximately 260 μm beneath the treated surface. Repeated processing could exacerbate the plastic deformation on the surface layer, resulting in finer grains. We can conclude that the surface grain refinement mechanism of SMA490BW welded joints is related to the high density of dislocation tangles and dislocation walls. © 2017, University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg.

Metallographic structure,mechanical properties,and process parameter optimization of 5A06 joints formed by ultrasonic-assisted refill friction stir spot welding

Novel hybrid refill friction stir spot welding （RFSSW） assisted with ultrasonic oscillation was introduced to 5A06 aluminum alloy joints. The metallographic structure and mechanical properties of 5A06 aluminum alloy RFSSW joints formed without ultrasonic assistance and with lateral and longitudinal ultrasonic assistance were compared, and the ultrasonic-assisted RFSSW process parameters were opti- mized. The results show that compared with lateral ultrasonic oscillation, longitudinal ultrasonic oscillation strengthens the horizontal bond- ing ligament in the joint and has a stronger effect on the joint＇s shear strength. By contrast, lateral ultrasonic oscillation strengthens the ver- tical bonding ligament and is more effective in increasing the joint＇s tensile strength. The maximum shear strength of ultrasonic-assisted RFSSW 5A06 aluminum alloy joints is as high as 8761 N, and the maximum tensile strength is 3679 N when the joints are formed at a tool rotating speed of 2000 r/rain, a welding time of 3.5 s, a penetration depth of 0.2 mm, and an axial pressure of 11 kN.

Kinetics of leaching refractory gold ores by ultrasonic-assisted electro-chlorination

The resources of refractory gold ores are abundant, and their effective treatment can bring good economic benefits. This paper investigated the kinetics of leaching gold from refractory gold ores by ultrasonic-assisted electro-chlorination. The effects of ultrasound time ratio, initial hydrochloric acid concentration and leaching temperature on the kinetic parameters were discussed. It is found that the leaching ratio goes up with all the factors increasing. The reaction kinetics is controlled by diffusion. When ultrasound improves the diffusion by reducing the diffusion resistance, the activation energy increases to 37.1 kJ/mol.

Production and characterization of ZnO nanoparticles and porous particles by ultrasonic spray pyrolysis using a zinc nitrate precursor

ZnO nanoparticles and porous particles were produced by an ultrasonic spray pyrolysis method using a zinc nitrate precursor at various temperatures under air atmosphere. The effects of reaction temperature on the size and morphology of ZnO particles were investi- gated. The samples were characterized by energy dispersive spectroscopy, X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. ZnO particles were obtained in a hexagonal crystal structure and the crystallite shapes changed from spherical to hex- agonal by elevating the reaction temperature. The crystallite size grew by increasing the temperature, in spite of reducing the residence time in the heated zone. ZnO nanoparticles were obtained at the lowest reaction temperature and ZnO porous particles, formed by aggregation of ZnO nanoparticles due to effective sintering, were prepared at higher temperatures. The results showed that the properties of ZnO particles can be controlled by changing the reaction temperature in the ultrasonic spray pyrolysis method.

Electro-oxidation process and mechanism of molybdenite decomposition under ultrasonic effect

According to the characteristics and shortcomings of the traditional roasting process and the electro-oxidation process in the molybdenum metallurgical industry, the ultrasound electro-oxidation process was proposed to strengthen the oxidative decomposition or leaching of molybdenum. Laboratory work was carried out in an electrochemical cell with 15 mm electrode spacing at 25℃ under ultrasonic effect. The optimum conditions were found through experiments. The electro-oxidation mechanism of molybdenite decomposition under ultrasonic was investigated. A model of electro-oxidation mechanism of molybdenum under ultrasonic was given.

Development of Aluminium Based Hybrid Metal Matrix Composites for Heavy Duty Applications

The present study deals with the investigation of dry sliding wear behavior of aluminium alloy based composites, reinforced with silicon carbide particles and solid lubricants such as graphite/antimony tri sulphide (Sb2S3). The first one of the composites (binary) consists of Al. with 20% Silicon Carbide particles (SiCp) only. The other composite has SiCp and solid lubricants: Graphite + Sb2S3 (hybrid composite) at solid state. Both composites are fabricated through P/M route using “Hot powder perform forging technology”. The density and hardness are measured by usual methods. The pin-on-disc dry wear tests to measure the tribological properties are conducted for one hour at different parameters namely load: 30, 50 and 80N and speed: 5, 7 and 9m/s. The tested samples are examined using scanning electron microscope (SEM) for the characterization of microstructure and tribolayer on worn surface of composites. The results reveal that wear rate of hybrid composite is lower than that of binary composite. The wear rate decreased with the increasing load and increased with increasing speed. The results of the proposed composites are compared with iron based metal matrix composites (FM01N, FM02) at corresponding values of test parameters. These iron based metal matrix composites are also fabricated by P/M route using ‘Hot powder perform forging technology’. The comparative study reveals that the proposed composites have lower friction coefficient, less temperature rise and low noise level;however they have little higher wear rate. It is concluded that the hybrid composite has acceptable level of tribological characteristics with blacky and smooth worn surface.

Application of subband adaptive filtering techniques to ultrasonic detection in multilayers

The ultrasonic testing for the defects of complete disbond in multi-layered structure with lower acoustic impedance beneath a high acoustic impedance overburden is one of the difficult problems in ultrasonic nondestructive testing field. A model of a multi-layered steel-rubber composite plate is depicted. Because the acoustic impedance of the steel differs far from that of the couplant water and the rubber, the energy of the signal reflected from the debonded rubber layers is very weak. More over, the flaw echoes are masked by the strong echoes reverberated in the steel plate. It's nearly impossible to identify the debonding echoes directly. The subband adaptive filtering method is discussed in the paper, where the subband decomposition is performed by mutual wavelet packets decomposition on the criterion of maximizing the cross-correlation between the signals. The simulations on both synthetic and real signals are presented. The echoes from the delaminated flaw at the depth of 5 mm in the rubber from the calculated signal, and echoes from the flaw at the depth of 3 mm from the real signal are extracted successfully.

Application of the digital matched-filter technique to ultrasonic non-destructive testing

Acoustic-pulse compression is obtained in systems with different timebandwidth products by applying the digital matched-filter technique to ultrasonic non-destructive testing. The signal is linearly frequency -modulated (LFM) pulse and the digitized electrical-excitation signal itself is used as a digital matched filter. Experimental results are in good agreement with theory. Suppressions of side lobes achieve -41.9 dB and -41.5 dB for the Hamming and Gaussian weighted signals respectively. It shows that the application of the digital matched-filter technique improves the performances of a ultrasonic testing system explicitly.

Powder metallurgy processed metal-matrix friction materials for space applications

Owing to the increasing demand for tribological brakes for space applications, the development of novel materials and advanced technologies is necessary. This paper presents the design, characterization, and realization of powder metallurgy processed metal-matrix friction materials intended for the above-mentioned tribological brakes. Selecting appropriate ingredients, which provides an effective way to tailor the properties of the friction material, is evolving as a strategy to meet the design requirements. The tribological behaviors of the friction material are experimentally investigated under different conditions, and special attention is focused on the vacuum tribology. Examinations and analyses of the friction surface and subsurface corroborate the wear mechanism. In addition, the erosion resistances of the friction material are evaluated by exposure tests of ultraviolet irradiation and atomic oxygen. Finally, present and potential space applications of the friction material are also introduced based on experimental studies.

ULTRASONIC INVESTIGATION OF BLOOD

Ultrasonic biophysicists and physicians have continuously exhibited great interest in studying the ultrasonic properties of blood. It is shown that compressibility of red cell appears to be inversely proportional with its hemoglobin content. Among ultrasonic attenuation produced by red cell structure level in blood, absorption of red cell plays predominant role, viscous relative motion loss accounts for less than 15%, and cell scattering contribution is negligible. The coagulation process of blood is accompanied by significant change of sound parameters. The marked advantage has been found in test of blood coagulation process by using ultrasonic technique than the traditional viscous method. Blood coagulation causes sound attenuation, sound backscattering and nonlinearity parameter B/A to increase, but the attenuation frequency dependence hardly changes. All of these findings are of an important realistic significance for developing ultrasonic medicine.

超声空化在船舶与海洋工程中的应用

Biofouling on ships and offshore structures has always been a difficult problem to solve,which not only jeopardizes the structural strength but also brings great economic losses.Ultrasonic cavitation is expected to solve this problem due to its characteristics of no damage to structures and no pollution.Starting from the phenomenon and mechanism of ultrasonic cleaning,this paper introduces the application of ultrasonic cavitation in ship,pipeline and oil cleaning as well as ballast water treatment.By reviewing the existing studies,limitations such as insufficient ultrasonic parameter studies,lack of uniform cleanliness standards,and insufficient cavitation studies are summarized to provide traceable research ideas for improving ultrasonic cavitation technology and to guide the expansion and improvement of its applications.

Process−microstructure−properties relationship in Al−CNTs−Al2O3 nanocomposites manufactured by hybrid powder metallurgy and microwave sintering process

Al−2CNTs−xAl2O3 nanocomposites were manufactured by a hybrid powder metallurgy and microwave sintering process.The correlation between process-induced microstructural features and the material properties including physical and mechanical properties as well as ultrasonic parameters was measured.It was found that physical properties including densification and physical dimensional changes were closely associated with the morphology and particle size of nanocomposite powders.The maximum density was obtained by extensive particle refinement at milling time longer than 8 h and Al2O3 content of 10 wt.%.Mechanical properties were controlled by Al2O3 content,dispersion of nano reinforcements and grain size.The optimum hardness and strength properties were achieved through incorporation of 10 wt.%Al2O3 and homogenous dispersion of CNTs and Al2O3 nanoparticles(NPs)at 12 h of milling which resulted in the formation of high density of dislocations and extensive grain size refinement.Also both longitudinal and shear velocities and attenuation increase linearly by increasing Al2O3 content and milling time.The variation of ultrasonic velocity and attenuation was attributed to the degree of dispersion of CNTs and Al2O3 and also less inter-particle spacing in the matrix.The larger Al2O3 content and more homogenous dispersion of CNTs and Al2O3 NPs at longer milling time exerted higher velocity and attenuation of ultrasonic wave.

在役压力管道的超声检测技术综述

压力管道在工业生产中具有关键性的作用,但由于多种因素的影响会导致出现安全事故,必须引起高度重视。在役压力管道必须定期检测,确保管道壁厚和各处焊缝符合技术标准要求。随着科学技术的不断进步,数字信号分析、自动成像等新型技术与超声检测技术相融合,产生了超声导波检测技术、衍射时差法超声检测技术(TOFD)、超声相控阵检测技术等,广泛应用于在役压力管道检测。激光超声检测、电磁超声C扫描检测、全自动超声波检测(AUT)等技术成为未来发展趋势。

中药外敷联合复合超声关节治疗仪治疗膝骨关节炎的临床效果

目的探究中药外敷联合复合超声关节治疗仪在膝骨关节炎(KOA)中的应用效果。方法选取2022年8月至2023年8月就诊于安阳市中医院的99例KOA患者为研究对象,随机分为3组,每组33例。超声组接受超声关节治疗仪治疗,中药组接受中药外敷治疗,联合组接受中药外敷联合超声关节治疗仪治疗。对比3组疗效及治疗前后西安大略和麦克马斯特大学骨关节炎指数(WOMAC)、视觉模拟评分法(VAS)、奎森功能演算(Lequesne)指数评分、成纤维细胞生长因子2(FGF-2)、Ⅰ型胶原C-末端肽(CTX-I)、软骨寡聚基质蛋白(COMP)及不良反应。结果联合组总有效率[93.94%(31/33)]高于超声组[75.76%(25/33)]、中药组[72.73%(24/33)](P<0.05),超声组与中药组总有效率对比,差异无统计学意义(P>0.05);治疗3个疗程后联合组FGF-2高于超声组、中药组,CTX-1、COMP、Lequesne、WOMAC评分低于超声组、中药组(P<0.05),超声组、中药组组间对比,差异无统计学意义(P>0.05);治疗3个疗程后联合组静态、动态VAS评分<中药组<超声组(P<0.05);治疗期间3组均未出现不良反应。结论中药外敷与复合超声关节治疗仪联合治疗KOA患者效果确切,可有效调节骨代谢指标,有助于缓解患者疼痛感,恢复膝关节功能。

分析多模式镇痛下持续髂筋膜间隙阻滞与收肌管阻滞对老年患者全膝关节置换术后快速康复的影响

目的探讨对老年人全膝关节置换术患者在多模式镇痛下分别给予超声引导下持续髂筋膜间隙阻滞以及收肌管阻滞对术后快速康复的影响。方法随机选取2020年2月—2022年11月常州市中医医院收治的60例老年人全膝关节置换术患者为研究对象,以随机数表法分为研究组和参照组,每组30例。参照组在多模式镇痛基础下施以超声引导下持续髂筋膜间隙阻滞,研究组在多模式镇痛基础下施以超声引导下持续收肌管阻滞。对比两组患者动态视觉模拟评分法(Visual Analogue Scale,VAS)评分、术后各时间点静息状态VAS评分、美国特种外科医院膝关节评分量表(Hospital for Special Surgery Knee Score,HSS)评分以及膝关节关节活动度(Range of Motion,ROM)。结果术后6、12、24、48 h,两组VAS评分比较,差异无统计学意义(P均>0.05)。研究组HSS评分为(71.25±7.25)分,高于参照组的(63.55±6.79)分,差异有统计学意义(t=4.246,P<0.05)。术后3、7、10、12 d,研究组ROM均高于参照组,差异有统计学意义(P均<0.05)。结论临床对老年人全膝关节置换术患者在给予镇痛干预期间,同超声引导下持续髂筋膜间隙阻滞比较,超声引导下持续收肌管阻滞方法的有效应用,可对患者的术后早期康复给予明显促进。

人工智能技术在有色金属冶炼能源管理中的应用研究

节能降耗是有色冶金企业重点关注的问题,加强企业能源管控水平是实现企业节能降耗的重要途径,但由于有色冶金企业生产流程长、工序多、工艺过程复杂,有色冶金企业的能源管控难度较大,利用人工智能技术实现企业合理的能源管控是未来的发展方向。基于此,本文在研究目前有色冶金企业能耗现状和能源管控特点的基础上,分析人工智能技术在有色金属冶炼能源管理中的应用场景和关键技术,为人工智能技术与有色冶金行业的结合提供了基础。

自制垫枕在超声引导下肘上PICC置管过程中的应用

目的 探究自制垫枕在超声引导下行肘上经外周静脉穿刺中心静脉(PICC)置管术的临床应用效果。方法 选取2022年1月至2022年12月于赣南医学院第一附属医院肿瘤内科行超声引导下肘上PICC置管的患者120例作为研究对象,采用随机数字表法分为对照组(60例)和试验组(60例)。其中对照组采用临床常规方法进行PICC置管,试验组使用自制垫枕放置于手臂下进行PICC置管。分析比较两组患者血管成像效果、超声探头纵轴与操作台的平面角度、一次性穿刺成功率、置管成功率以及置管时间。结果 试验组患者置管前血管成像效果优于对照组(P<0.05);试验组患者血管成像效果良好时操作台与探头纵轴垂直率高于对照组(P<0.05);对照组患者置管成功率为98.33%、试验组为100.00%,两组对比无统计学意义(P>0.05);试验组患者一次穿刺成功率(98.33%)高于对照组(88.33%)(P<0.05),且多次进针及多次送导丝情况低于对照组(P<0.05);试验组患者的置管时间在30~45 min范围内的例数多于对照组(P<0.05),> 45 min的例数少于对照组(P<0.05)。结论 使用自制垫枕在超声引导下进行肘上PICC置管,能够有效提高血管成像的效果。此外,操作台与超声探头纵轴呈垂直角度更加利于操作,降低了多次进针及送导丝次数,进一步缩短了置管时间。