超声波谱法在岩石破裂特性研究中的应用

一、前言岩石破裂特性的研究是岩石力学中的一个重要课题。岩石破裂特性与应力途径及应力条件有关。不同应力途径或应力条件下岩石破裂过程的研究,对于揭示岩石破裂机制、工程岩体稳定性、地震预报及灾害的防治、采油、采矿的控制等方面的研究都有着重要的意义。研究岩石破裂的常规方法比较重视试件受力下产生的线应变及由此推算出的体积应变随应力差的变化规律。同时亦观察微破裂产生的声发射现象(如AE的频度与能量等),以及超声脉冲波的传播速度、电阻率、磁导率等物理量的变化以及与应力-应变的关系。

岩石超声波谱测试技术

岩石超声波谱测试技术是目前岩石力学实验研究的一种重要方法 ,具有广阔的应用前景 .

最近的激光超声波谱术

以材料测试和物理性质研究为目的,测量超声波的声速和吸收,广义上可称为超声波谱术,在金属、半导体、陶瓷、液体、高分子、生物体等所有的材料中有广泛的应用。测定中根据被测物质、频率、测定环境等不同条件,选择各自最佳的适用技术。本文就超声波谱技术的动向,总结以往几年的工作,介绍目前的状态,展望未来几年的发展,重点在于促进该项技术进步的方法以及今后要充实的技术。1.过去十年超声波测量很早便采用脉冲法和共振法。

基于超声波多普勒法的流通截面分区流速测量的研究

传统的超声波多普勒流量计测量的结果是大面积区域内具有统计意义的平均流速，不能反映流速在流通截面上的分布，当雷诺数变化很大时，测量误差很大。基于超声波多普勒效应，本文首次提出了通过对测量信息窗区域的控制，来实现在管流内部进行流速分区测量，进而测量出流速在流通截面上的分布。研制出发射传感器和接收传感器，分别能够产生细长的发射声束和接收声束，使得信息窗区域面积得以控制在很小的范围内，约 ２．１× ４．８ ｍｍ２，位置也被控制在设计值处，满足分区测量要求；在自行设计的模拟管道流动装置中，成功地进行了控制信息窗区域面积和位置的实验，测量值与设计值吻合很好。实现了管道流通截面上的流速分区测量。

激光超声无损检测技术及其在岩体物性测试中的应用

激光超声无损检测技术是材料无损检测的一种重要手段,是目前人们所关注的一种重要的检测方法.文章阐述了激光超声的激发原理和激光超声信号检测方法,详细介绍其在对岩体物性测试中的应用,并且针对目前存在的一些技术难题指出了今后的解决方向.

Determination of contents of 10-Hydroxycamptothecin in Camptotheca acuminata by high-performance liquid chromatogram

The determination method of 10-hydroxycamptothecin in Camptotheca acuminata fruits by high-performance liquid chromatogram (HPLC) was studied. The HPLC analysis was performed on a HIQ sil C18(4.6×250 mm) column with mobile phase of acetonitrilewater (3:7, V:V), flow rate 1 mLmin-1 and UV detective wavelength 266 nm. Extracting 10-hydroxycamptothecin by ultrasonic method from fruits of C. acuminata to prepare samples for analysis was systematically discussed. The optimal extraction condition was carried out by 60% alcohol solution at 60℃ for 50 minutes.

GC-MS Analysis of Essential oil and n-Hexane Extract from Moso Bamboo

[Objective] This study aimed to analyze the chemical composition and yield of essential oil and n-hexane extract from moso bamboo to find active compounds with potential value. [Method] Essential oil and n-hexane extract were respectively extracted from moso bamboo of four different ages by using hydrodistillation and ultrasonic-assisted extraction with n-hexane, and analyzed with gas chromatography/mass spectrometry （GC/MS）. [Result] The results show that cedrol （46.39%） is the first principal volatile component in essential oil of the middle stem of 7-year old moso bamboo; dibutyl phthalate （59.46%） is the first principal volatile component in n-hexane extract of the middle stem of 3-year old moso bamboo; yield of n-hexane extract is higher than that of essential oil from moso bamboo. [Conclusion] Cedrol is an active compound with potential value.

EXPERIMENTAL RESEARCH ON THE ULTRASONIC TECHNIQUE AND ITS APPLICATION IN STUDYING ROCK PROPERTIES

The experimental installation and measurement system of ultrasonic wave property in rocks during complete stress-strain process were established and perfected. The interrelations between ultrasonic wave property of muds tone, sands tone and limestone specimens during complete stress-strain process and their mechanic property were investigated. A new type of device for the observation of surrounding rock stability-borehole ultrasonic device with completely dry coupling was developed to get better coupling and more accurate measurement data comparing with those of water coupling situation. Preliminary study on the application of ultrasonic measurement technique at belt conveyor roadway of north wing in Baodian Coal Mine (Shandong province) was conducted. Based on the interrelations between the complete stress-strain properties of specimens and their wave properties, the structural properties of surrounding rocks, the range of yield zones, and the change of stresses within surrounding rocks when a longwall face was across over the roadway were analyzed.Therefore,a new and feasible way was found for the research on the deformation law of surrounding rock of roadway and rational selection of support parameters.

Ultrasound guided percutaneous treatment for splenic abscesses: The signifi cance in treatment of critically ill patients

AIM: To analyze the results of ultrasound guided percu- taneous needle aspiration (PNA) and percutaneous catheter drainage (PCD) in the treatment of splenic abscess. METHODS: Thirty-six patients (14 females and 22 males, with an average age of 54.1 ± 14.1 years) with splenic abscess were treated with ultrasound guided PNA and/or PCD. Patients with splenic abscess < 50 mm in diameter were initially treated by PNA and those with abscess ≥ 50 mm and bilocular abscesses were initially treated by an 8-French catheter drainage. The clinical characteristics, underlying diseases, organism spectra, therapeutic methods, and mortality rates were analyzed. RESULTS: Twenty-seven patients had unilocular and 9 bilocular abscess. PNA was performed in 19 patients (52.8%), and 8 of them (42.1%) required PCD because of recurrence of abscess. In 17 patients (47.2%), PCD was performed initially. PCD was performed twice in six patients and three times in two. PNA was defi nitive treatment for 10 and PCD for 21 patients. One patient with PCD was referred for splenectomy, with successful outcome. In all 4 deceased patients, malignancy was the underlying condition. Twenty-one patients (58.3%) underwent 33 surgical interventions on abdomen before treatment. Cultures were positive in 30 patients (83.3%). Gram-negative bacillus predominated (46.7%). There were no complications related to the procedure. CONCLUSION: Percutaneous treatmnet of splenic abscess is an effective alternative to surgery, allowing preservation of the spleen. This treatment is especially indicative for the patients in critical condition postoperatively. We recommend PNA as primary treatment for splenic abscesses < 50 mm, and PCD for those ≥ 50 mm in diameter and for bilocular abscesses.

Determination of contents of eight alkaloids in fruits of Macleaya cordata (Willd) R. Br. from different habitats and antioxidant activities of extracts

A reliable ultrasound-assisted extraction （UAE） method combined with HPLC-UV for quantification of eight active alkaloids in fruits of Macleaya cordata （Willd） R. Br. was developed. The optimization conditions of UAE were obtained by using Box-Behnken design of response surface methodology. Chromatography was carried out using a Kromasil C18 column by gradient elution with 0.1% phosphoric acid aqueous solution for HPLC-UV. All calibration curves showed good linear correlation coefficients （R^2〉0.999 6） and recoveries （from 97.3% to 104.9%） were acceptable. 1,1-diphenyl-2-picrylhydrazyl （DPPH） method was employed to test the antioxidant activity of the extract from the samples. The proposed method was successfully applied to quantifying eight components in nine samples of M.cordata, and significant variations of alkaloid contents and antioxidant aetivity of the samples from different habitats were demonstrated. It presents a powerful proof for the selection of the best sources to extract eight kinds of alkaloids.

PROGRESS OF ACOUSTIC WAVE TECHNIQUE ANDITS APPLICATION IN UNDERGROUND PRESSURE MEASUREMENT

This paper carries out tbe experirnent study on the correlation between am stress-strain process of rock samples and the acoustie parameter change of rock by using the measurement system of KS acoustic wave data processing device. On the spot, the stability of surrounding rock is studied by means of experiments on the relationship between the change process (from elastie to plastic failure zone) in surrounding rock of roadway and the change law of acoustic parameters of rock. These acoustie parameters inelude wave amplitude, spectral amplitude, spectrum area, spectral density,wave veloeity and attenuation coefficient etc.

"Smart" ultrasonic pig design and its signal processing research

This paper introduces the design and development of intelligent ultrasonic ＂pig＂ used for seabed pipeline inspection. The data acquisition system （DAS） and the signal processing method are presented. The DAS was designed using a muhi-DSP based structure. The signal processing method adopted a well-enhanced split-spectrum processing （SSP） based on weighting algorithm according to statistical times, which was the statistical distribution of the discrete signals selected by the minimization algorithm. Furthermore, the data compressing method was discussed. It assures the mass data to be processed and compressed in real-time. The effectiveness of the method was proved by laboratory experiments. The research provides an excellent base for further development of the ultrasonic pig.

Performance of engineered cementitious composite containing stone slurry powder waste

Most of the materials used in engineered cementitious composite are fine in size to achieve ductile nature.Stone slurry powder(SSP)is an inert material obtained from stone industries as by-product which may cause hazardous impact on environment.In this research work,partial replacement of silica sand(SS)and fine sand(FS)by SSP with different contents(25%and 50%each)for making engineered cementitious composite has been explored.The performance was evaluated on the basis of strength,tensile strain,mid span deflection capacity,ultra-sonic pulse velocity and microstructure.Mechanical strength was found to be increased at 25%SSP in both replacements;whereas,strength decreased slightly at 50%replacement.Tensile strain,mid span deflection and quality of concrete were enhanced with increase in SSP content.Using SSP formed denser cementitious composite can help to save the natural resources and contribute in making green cementitious composite.

Separation of Acearylenes from High-Temperature Coal Tar

High-temperature coal tar was extracted with petroleum ether （PE） under ultrasonic irradiation and the extracts were analyzed with gas chromatograph/mass spectrometer. The acearylene fractions including acenaphthylene, aceanthrylene and cyclopentapyrene were enriched together and named E, which was then transferred to a car- tridge in Isolera-One flash chromatography. Three groups of compounds were eluted out with ethyl acetate/PE mixed solvent （volume ratio 1：9） and named E1, E2 and E3 according to their main components. Acenaphthylene accounted for 78.2% in El, aceanthrylene 71.6% in E2 and cyclopentapyrene 75.9% in E3, respectively. The three groups of acearylenes were purified by Sephadex LH-20 column chromatography with ethanol/cyclohexane mixed solvent （vol- ume ratio 1：4）, and then confirmed with nuclear magnetic resonance spectrometer. This method indicates that flash chromatography has a good effect on separating the compounds with a similar structnre after extraction under ultrasonic irradiation.

The detection and significance of polycyclic aromatic hydrocarbons in human pancreatic cancer

Objective:The aim of this study was to investigate the effect of polycyclic aromatic hydrocarbons (PAHs) on the occurrence of human pancreatic cancer.Methods:PAHs in human pancreatic cancer,adjacent pancreatic cancer tissues and tissues without pancreatic cancer were extracted by ultrasonic extraction (UE).And then the extracts were cleaned up by solid phase extraction and analyzed by high performance liquid chromatography (HPLC) with fluorescence spectroscopy.Results:Four kinds of PAHs were detected,which were chrysene,2-methylanthracene,pyrene and benzo (a) pyrene.The contents of the four PAHs were not statistically significant between pancreatic cancer and adjacent tissues (P > 0.05).The contents of 2-methylanthracene,pyrene and benzo (a) pyrene in pancreatic cancer and adjacent tissues were higher than tissues without pancreatic cancer,the differences were statistically significant (P < 0.05).The contents of chrysene in the three kinds of pancreatic tissues were not statistically significant (P > 0.05).Conclusion:PAHs were found in human pancreatic tissues.Human pancreatic tissues have extremely strong ability of bio-concentrating PAHs.PAHs might play an important role in the occurrence of human pancreatic cancer.

Synthesis of ITQ-2 Zeolites and Catalytic Performance in n-Dodecane Cracking

ITQ-2 zeolites were prepared by sequential alkali-swelling and ultrasonic-delamination of precursor MCM-22 and characterized by X-ray powder diffraction, scanning electron microscopy, nitrogen adsorption-desorption, ammonia temperature-programmed desorption and in-situ Fourier-transform infrared spectroscopy. The delamination induced a change in the morphology of ITQ-2 zeolites from aggregated thin platelets to scattered platelets, together with a significant increase in external specific surface area, which reached a plateau at the ultrasonic treatment time of 3 h. The catalytic cracking of n-dodecane over ITQ-2 zeolites was evaluated with ITQ-2 coated on the inside wall of a tubular reactor at 550 ℃ and 4 MPa. The sample obtained by ultrasonic treatment of 3 h （ITQ-2-3） gave the highest initial conversion of n-dodecane, whereas those of 5 h and I h gave the conversion even lower than MCM-22, which was in agreement with the trend of the ratio of strong Lewis acid to the total acid amount. Although the amount of cokes deposited on ITQ-2-3 was larger than that on MCM-22, the former deactivated slowly, suggesting that a large external specific surface area benefits the stability of zeolite coatings,

Analysis of volatile components in saffron from Tibet and Henan by ultrasonic-assisted solvent extraction and GC-MS

To determine the chemical constituents of volatile components in saffron from the Tibet Autonomous Region and the Henan Province of China and to compare the chemical composition difference in the saffron,the total volatile components were extracted by ultrasonic-assisted solvent extraction（USE）,using five different solvents：diethyl ether,ethanol,ethyl acetate, dichloromethane and acetone,analyzed using gas chromatography-mass spectrometry（GC-MS）and compared to the standard MS data,and their relative contents were calculated by area normalization.The results showed both that USE was an efficient and rapid method for the extraction of the volatile components from saffron and that the components extracted from the same sample using different solvents were different.Comparison of the experimental results of saffron from the Tibet Autonomous Region and the Henan Province of China showed that their volatile components were different in their chemical composition and in their relative percentages.USE/GC-MS is a simple,rapid,and effective method for the analysis of volatile oil components in saffron.

Joint spectrogram segmentation and ridge-extraction method for separating multimodal guided waves in long bones

Ultrasonic guided waves (GWs) can be used to evaluate long bones effectively because of the ability to provide the information of the whole bone. In this study, a joint spectrogram segmentation and ridge-extraction (JSSRE) method was proposed to separate multiple modes in long bones. First, the Gabor time-frequency transform was applied to obtain the spectrogram of multimodal signals. Then, a multi-class image segmentation algorithm was used to find the corresponding region of each mode in the spectrogram, including an improved watershed transform and a region growing procedure. Finally, the ridges were extracted and the time domain signals representing individual modes were reconstructed from these ridges in each region. The validations of this method were discussed by simulated multimodal signals with different signal-to-noise ratios (SNR). The correlation coefficients between the original signals without noise and the reconstructed signals were calculated to analyze the results quantitatively. The results showed that the extracted ridges were in good agreement with generated theoretical dispersion curves, and the reconstructed signals were highly related to the original signals, even under the SNR=3 dB situation.