2019 volumne 40卷 Issue 06
Sun Xuguang1,2,Wang Chunkai1,2,Liu Chang 1,Sun Jianhai 1,Xue Ning 1,2
Abstract: This paper reports a 6 x 8 flexible resistive tactile sensor array composed from multi-walled carbon nanotubes (MWCNTs)-polydimethylsiloxane (PDMS) composite. The fabrication process of the sensor array is simple and compatible for large area and volume manufacture. The sensor array has properties of high flexibility and sensitivity contributing from the composite anomalous surface structure on the sensing elements. The sensitivity of the tactile sensor is 16.9-5.41 kPa-1 in the low pressure range (< 300 Pa) and > 0.5 kPa-1 in the pressure range of 1.3 kPa. Moreover, an array scanning system has been established and the applied pressure can be detected , digitalized and real-time displayed. This work has high potential in low range pressure detection and artificial skin applications.
Mary 1,2,Zhang Wentao 1,2,Li Fang1,2
Abstract: In order to measure static magnetic field, this paper presents a novel optical fiber magnetic field sensor with the resolution of μT level. This sensor is expected to be used in resource exploration, power grid monitoring, geomagnetic navigation and so on. FBG-FP coupled with Terfenol-D is used as sensing element, and a NdFeB magnet is used to apply bias magnetic field. Meanwhile, to compensate the environmental temperature, another FBG-FP coupled with Monel-400 is used as a reference. The measurement sensitivity of the sensor is 1.5×10-3 pm/μT, which results in a magnetic induction resolution of 0.67 μT. The experimental results show that the sensor exhibits excellent linearity and directivity in response to static magnetic field
Yu Wangke1,2,He Xiuli 1,Gao Xiaoguang 1,Jia Jian 1,Li Jianping 1
Abstract: Serious malodor pollution e vents bring many environmental and health problems and have aroused broad social concern. In view of the need for on-site detection and component analysis of malodor, the corona discharge ion mobility spectromet er (CD-IMS) was proposed for malodor detection. T he parameters of the system were optimized and dimethyl sulfide, dimethyl disulfide, methyl mercaptan and the mixture of them were detected. The detection limits (3 times the baseline noise) of 0.93×10-3, 0.019 and 0.144 mg/m 3, the linear ranges of 0.03-0.15, 0.2-5.0 and 0.4-1.0 mg/m3, the correlation coefficients (r 2) of 0.996, 0.994 and 0.990 were obtained for dimethyl sulfide, dimethyl disulfide and methyl mercaptan, respectively. The relative standard deviation (RSD) for the malodor was below 2.5%
Liu Caixia 1,Zhu Wenjin 1,Wang Zhiqiang 1,Guo Xiaohui 1,Liu Ping 1,Huang Ying 1,2
Abstract: In order to improve the sensitivity and dynamic response characteristics of the tactile sensor, the authors prepared conductive microcellular foams of GNPs/CB/SR nanocomposites with favorable electrical properties and elasticity based on physical foaming technology, and utilized it as composite dielectric layer to design high-performance flexible capacitive tactile sensor. The foaming agent concentration was analyzed to investigate the influence on the electrical properties of porous structure composite dielectric layer, and the microstructure and morphology of porous structure composite dielectric layer were characterized. The capacitive tactile sensing unit structure of porous structure composite dielectric layer, working mechanism and corresponding performance optimization methods were systematically analyzed. Meanwhile, the authors conducted performance testing for the capacitive tactile sensing unit, and designed expandable tactile sensing array. And the capacitive tactile sensing array information extraction system based on high-performance microprocessor STM32F103VET6 and capacitive digital converter AD7147-1 to achieve real-time pressure distribution perception. The experimental results indicate that the proposed capacitive tactile sensor with porous structure composite dielectric layer possess good detection sensitivity and dynamic characteristics, and can be used as robotic electronic skin to achieve high-performance tactile perception
Que Huiying1,2,Chen Chaoyang 1,Kong Xirui1,2,He Chengfa 1
Abstract: The goal of this work was to investigate the relevant dosimetric and luminescent properties of LiMg- PO4 :Tb a high sensitivity optically stimulated luminescence ( OSL) material, synthesized by a simple solid- state diffusion method. The dosimetric properties of the material using a continuous wave-optically stimulated luminescence ( CW-OSL) technique were studied. The influencing factors affecting the sensitivity of the OSL material were also explored. The experimental results showed that the material exhibited high sensitivity when the dopant concentration was 0. 2% mol and the particle size was 50 ~ 150 |xm. In addition, The material was found to have all the good dosimetric characteristics, such as high sensitivity ( 3 times less than the commercially available A12O3 :C, Landauer Inc., USA) , tissue equivalence (low-Z, Zeff« 11. 8) ,wide range of dose response ( 0. 1 Gy~ 1. 0 kGy) , etc., which made the material potential for personal and medical dosimetry applications in radiation dosimetry.
Li Na 1,2,Xiang Qun1,Cheng Zhixuan 1,Wang Xiaohong 1,Xu Jiaqiang 1
Abstract: In view of the current cumbersome preparation process and the low sensitivity to formaldehyde of gas sensing materials, this paper mainly prepares synthetic porous SnO2 hollow sphere materials by using the ratio of ethanol to water and use it to detect the low concentration formaldehyde. The structure and morphology of the materials were characterized by XRD, SEM and TEM. When the volume ratio of ethanol to water is 3.0:5.0, the prepared porous SnO2 hollow spheres grow uniformly and have a diameter of about 400 nm. The gas sensitivity test results show that the optimum operating temperature of SnO2 hollow sphere material is 210℃, the response value to 50 mg/L formaldehyde can reach 52.5, the response and recovery time are 14 s and 33 s, and the response value to other gases is lower. The material was also tested continuously in the range of formaldehyde concentration range of 1-50 mg/L, the lowest detection limit was calculated to be as low as 20 ug/L, indicating that it can be used for the detection of low concentration formaldehyde.
Govan 1,2,Zhang Xusheng 1,Wang Min 1,Zhang Junyu 1,Wang Ping 1
Abstract: Hydrogen and methane breath test has been widely used in the diagnosis of sugar intolerance, small intestinal bacterial overgrowth (SIBO) and other gastrointestinal diseases. The gold standard for clinical diagnosis of SIBO is small intestinal fluid culture, while the sampling is invasive and the sample location is limited and easy to be contaminated. Therefore, clinical experience is often used for the diagnosis of SIBO with poor accuracy and risk of abusing the antibiotics. In this paper, hydrogen and methane in breath were selected as the markers and a novel electronic nose was developed which can detect the concentration of hydrogen and methane in breath with the detection range is 1-200 ppm, the resolution is 1 ppm, and the precision is less than 10%. The results were corrected by the carbon dioxide concentration to eliminate the effect of the dilution of outside gas, the patient breathing mode and other factors on the alveolar gas. The 47 cases of healthy people and patients were collected, and the types of concentration curve were judged accurately, and the SIBO diagnostic model was established. This method has the advantages of high specificity, non-invasive and simplicity of operation, so that can be used for the detection of increasing volume of clinical and domestic patients.
Cao Chenlu,Cao Chunmei,Guo Meiyuan,Lu Qifang,Zhan Zili;Gao Jian
Abstract: Nano-sized ZnO materials were prepared using the porous structure of metal-organic frameworks (MOFs) material as the precursor, and the sensing performance of this ZnO-based semiconductor nano-material with different ratios of Pd for the different concentrations of NO2 gas was studied, When the Pd doping is 1wt%, the doped ZnO nanomaterial has better gas-sensing response to NO2. The optimum operating temperature is 235 °C, and when the NO2 concentration is reduced to 5 ppm, the sample still has good gas sensing performance.
Xueli Liu1,2,Zhang Yufeng 1,Liang Yong 1,Li Junhong 1,Wang Wen 1
Abstract: In this contribution, a surface acoustic wave (SAW) based H2S sensor was proposed for by combining the SAW technology with fast response and TEA with selective absorption towards H2S. By means of the drop-coating method, a 200MHz SAW H2S sensing device with delay line configuration was developed, and collected into the differential phase discrimination circuit, and the corresponding SAW H2S sensor system was constructed. The measured results in H2S gas experiments indicates that fast response (≤30s), high sensitivity (4.27 mV/ppm) and lower detection limit (0.14 ppm) were achieved. It means the proposed SAW sensor will be promising for sulfide sensing
Fan Shangchun,Zhang Jin,Zhu Liming
Abstract: The excellent mechanical and electrical properties of graphene make it an ideal material for nanoelectromechanical systems. As a resonator, graphene is expected to enable resonant pressure sensors to achieve higher measurement sensitivity in the low voltage range. In this paper, a resonator with graphene material as beam is designed with reference to a silicon resonant pressure sensor. The theoretical analysis and finite element simulation of the resonator are performed. The working mechanism is revealed, and the influence of the structural parameters of the resonator on the sensitivity is explored. The simulation results show that the sensitivity decreases with the thickness of the silicon film and the length of the beam, and increases with the length and depth of the groove side. The paper also proposes a preliminary processing scheme for harmonic oscillators.
Patiman Nizamuddin;Mariem Turgon;Ablizi Yimiti
Abstract: In this paper, [Zn2(bdc)2-(dpNDI)]n thin films were fabricated by In-situ growth method. The zinc nitrate, terephthalic acid (bdc) and N-N ’’- dianiline 4-pyridyl 1,4,5,8 -naphthalenediimide (dpNDI) were used as precursors, the tin-diffused glass waveguide was used as substrate, and was immersed in [Zn2(bdc)2 -(dpNDI)]n precurse solution for 5,10,15,20 and 25 h, at room temperature. The infrared spectroscopy (IR), high power scanning electron microscopy (SEM), UV-Vis spectroscopy and self-assembled optical waveguide sensing system were employed to investigate the structure, pore size, surface morphology ,optical properties and gas adsorbility of [Zn2(bdc)2-(dpNDI)]n thin films. The experimental results indicates that, while immersion for 20 h at the room temperature, the [Zn2(bdc)2-(dpNDI)]n thin film optical waveguides exhibit greater adsorption response to xylene gas, and the response of xylene gas is more greater 10 times than that of other gases.
Hu Guoqin,Sun Fangxing,Liu Jinghui,Chen Pengli
Abstract: In this study, FH is micronized via Supercritical solution rapid expansion process (RESS) to improve its dissolution rate of drug in the biological environment. And the effects of the process parameters such as the temperature and the pressure of equilibrium cell, the temperature of the collection vessel, the temperature of the nozzle, the diameter of the nozzle and the concentration of the entrainer on the size and morphology of the drug particles were investigated.The particles before and after RESS were characterized by optical microscopy,scanning electron microscope (SEM), X-ray diffraction (XRD) and thermogravimetry (TGA). Test results show that microparticles of FH was successfully performed by using RESS and The average particle size of Flourarizine Hydrochloride were in the range of 1.285μm to 6.893μm. The results of FT-IR, XRD, and TG-DSC indicate that the physical and chemical properties of flunarizine hydrochloride particles remained stable before and after the RESS process
Liz 1,Zhang Yu 1,Zhou Ying 1,Ma Chengliang 1,Huang Wenjiang 1,Ji Chen 2
Abstract: In this experiment, MoSi2 composite ceramics were prepared by wet-grinding and mixing nano-sized Al2O3 particles of the different volume fractions with Mo powder and Si powder (molybdenum-silicon molar ratio of 1:2), and its physical properties such as density, hardness and fracture toughness were tested. The phase composition, micro-morphology and micro-elemental composition of the prepared samples were analyzed by XRD, SEM and EDS. The effects of nano-Al2O3 particles with the different volume fractions on the properties of MoSi2 composite ceramics were discussed. The results show that: (1) The density, hardness and fracture toughness of MoSi2 can be effectively improved by adding a small amount of nano-Al2O3 compared with a single MoSi2 phase, the density, hardness and fracture toughness of nano-102%, 119% and 167% respectively; (2) Under the vacuum reaction hot-pressing sintering, a small amount of nano-Al2O3 incorporates the lattice distortion of the MoSi2 composite ceramics, which is beneficial to improve the fracture toughness; (3) As the amount of nano-Al2O3 increases, the dispersibility of nano-Al2O3 in the MoSi 2-based material decreases, resulting in the decrease of the physical properties?of the MoSi2 composite ceramic.
Xia Bogan,Xu Mengxia
Abstract: The transient elastohydrodynamic lubrication model of linecontact among roller bearing, gear, cam and other tribopairs are developed. The variations of thickness of the contact solid’s center film under free vibrations of the contact solid are solved based on the compound direct iterative method. According to the variation of the thickness of the contact solid’s center film, the influence of the dimensionless natural frequencies determined under different mass, the different initial disturbance modes and the different excitation frequencies on the equivalent stiffness and damping of the tribopairs are studied. The results demonstrate that the thickness of the contact solid’s center film fluctuates in the vicinity of the equilibrium position, and with the increase of mass, the vibration period of the contact solid increases and the vibration amplitude decreases.The dimensionless natural frequency determined under different mass has little effect on the stiffness and damping of the tribopairs. The stiffness and damping of the tribopairs are independent of the initial disturbance mode and have nothing to do with the excitation frequency.
Tao Zheng 1,Mao Songlei 1,Guo Qintao 2,Liu Xu 1
Abstract: The accurate finite element model is very important to the dynamic design of the structure. In view of the gear transmission system of large mechanical equipment, a precise finite element modeling method based on hierarchical correction is put forward. The whole transmission system is divided into sub structure, based on the experimental modal frequency data for the target value, the finite element model of surface modification technology on structure model was modified based on the response, and identify the uncertain parameters in the model. The results showed that the modified frequency is close to the experimental value, the mode correlation coefficient MAC value above 0.84, shows that the parameter identification validity and accuracy of the finite element model can be improved obviously, verifies the feasibility of precise modeling method based on the idea of layered correction is applied to a large machine design and analysis of dynamic characteristics of gear transmission system of mechanical equipment the. Finally, the response characteristics of the integrated transmission system are obtained, which provides a theoretical basis for the subsequent dynamic analysis of the system.
Wu Guodong,Zhang Aimei,Huang Xiao,Yao Pengwei
Abstract: In traffic surveillance video, it is necessary to detect the information of moving vehicles, however, the shadow of the vehicle is often wrongly detected as the vehicle itself, which directly affects the accuracy of the vehicle detection and brings difficulties to the technical processing behind the vehicle detection .In this paper, a vehicle shadow removal method based on color space, texture feature and edge feature is proposed. First, the background model is established by the traditional mixed gaussian method, and the foreground target is extracted.Second The shadow of the foreground target is detected by threshold method in HSI (Hue-Saturation-Intensity) space,because the detection based on color model is easy to detect the moving object itself as shadow, the LBP operator combined with edge feature detection method is used to extract the moving target.Finally, combining the foreground target detected by LBP operator and edge feature with the shadow object detected in HSI color space, the actual shadow region can be detected.The real moving foreground target can be obtained by removing the detected shadow area. The simulation results show that the proposed algorithm can effectively remove the shadow of moving vehicle in traffic surveillance video, and improve the detection rate of moving vehicle shadow by about 10%
Shi Gang,Koichi,Liu Zhongyu
Abstract: Drainage consolidation method is an effective method to improve the soft soil foundation such as muddy soil or fill soil foundation. However, when the soil layer is too thick, the sand drain may not penetrate the whole soft soil foundation due to the construction costs or construction difficulties. In the paper, the investigation is focused on the consolidation of partially penetrated sand-drained foundation, and the governing equations for the consolidation of soft ground with partially penetrated sand drains are put forward by introducing Hansob’s flow model. And the effect of the depth of sand drains, the parameters of Hansob’s flow model and the smear zone on consolidation behaviors is analyzed in detail. The results show that the depth of sand drains can affect the average consolidation degree of sand-drained foundation significantly, and the required consolidation time corresponding to Up=90% is about ten times more than that of ideal sand-drained foundation, when the depth of sand drains is 60% of the total depth of the foundation. The consolidation rate decreases with the increasing of the parametersandof Hansob’s flow, and it also decreases with the increasing of the scope of smear zone and the decreasing of the permeability coefficient of smear zone. Moreover, the scope and the permeability of smear zone have larger effects on the consolidation rate of the partially penetrated sand-drained foundation during the middle state of consolidation, while it has less effects on the consolidation rate during the last stage of consolidation.
Hu Yu1,2,Yao Aijun 1,Zhang Jiantao 3
Abstract: On the basis of typical metro shield tunneling engineering, this paper studies stability and safety of rain and sewage pipeline. With the application of combine method of model test and numerical simulation, the deformation of pipeline and distribution of stress which is induced by the tunnel excavation are analyzed. As shown by calculation: (1) The uniform distribution can be presented in the settlement curve of pipeline when the pipeline and tunnel is parallel. When l/D is 1.5, the supervision points will be laid out densely and supervised frequently at the range of 1.5D between tunnel face and tunnel end. (2) The protective measures of tension and compression should be taken on the top and bottom of pipeline respectively.
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