Study on Novel MEMS Hollow Microneedle Array

2007 ◽  
Author(s):  
Shuhai Jia ◽  
Yigui Li ◽  
Xiao Sun ◽  
Jun Zhu
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Outer Diameter ◽  
Microneedle Array ◽  
X Ray ◽  
Hollow Microneedle ◽  
Development Procedure ◽  
Inner Diameter ◽  
Exposure Technique ◽  
Mechanical Characters

A novel MEMS hollow microneedle array is fabricated through the exposure technique in deep X-ray lithography and development procedure in this paper. The method to fabricate microneedle array presented in this paper needn’t any special apparatuses, and is very easy to operate. A method to compensate the beam distribution of synchrotron radiation light source is described. The PMMA (polymethylmethacrylate) sheet is chosen as the material of microneedle. The length of the hollow microneedle fabricated is 160μ m. The outer diameter of microneedle is 80μm, and the inner diameter of microneedle is 40μm. The mechanical characters of microneedle, such as the force withstanding capabilities, are studied through both the theoretical analysis and numerical simulation of finite element method. The analysis results of the mechanical character show that the strength of microneedles fabricated in this paper is enough to pierce human skin.

Experimental and Numerical Evaluation of Small-Scale Cryosurgery Using Ultrafine Cryoprobe

2013 ◽  
Author(s):  
Junnosuke Okajima ◽  
Atsuki Komiya ◽  
Shigenao Maruyama
Keyword(s):  
Numerical Simulation ◽  
Temperature Distribution ◽  
Biological Tissue ◽  
Bioheat Transfer ◽  
Small Scale ◽  
Outer Diameter ◽  
Two Phase ◽  
Inner Diameter ◽  
Surgical Treatments ◽  
Tube Structure

Cryosurgery is one of the surgical treatments using a frozen phenomenon in biological tissue. In order to reduce the invasiveness of cryosurgery, the miniaturization of cryoprobe, which is a cooling device for cryosurgery, has been required. The authors have developed a ultrafine cryoprobe for realizing low-invasive cryosurgery by the local freezing. The objective of this study is to evaluate the small-scale cryosurgery using the ultrafine cryoprobe experimentally and numerically. The ultrafine cryoprobe has a double-tube structure and consists of two stainless microtube. The outer diameter of ultrafine cryoprobe was 550 μm. The inner tube, which has 70 μm in inner diameter, depressurizes the high-pressure liquidized refrigerant. Depressurized refrigerant changes its state to two-phase and passes through the gap between outer and inner tube. The alternative Freon of HFC-23 was used as a refrigerant, which has the boiling point of −82°C at 0.1 MPa. The cooling performance of this ultrafine cryoprobe was tested by the freezing experiment of the gelated water kept at 37°C. The gelated water at 37°C is a substitute of the biological tissue. As a result of the cooling in 1 minute, the surface temperature of the ultrafine cryoprobe was reached at −35°C and the radius of frozen region was 2 mm. In order to evaluate the temperature distribution in the frozen region, the numerical simulation was conducted. The two-dimensional axisymmetric bioheat transfer equation with phase change was solved. By using the result from the numerical simulation, the temperature distribution in the frozen region and expected necrosis area is discussed.

Fabrication and Characterization of Titanium Based Nanotubes

2009 ◽  
Vol 79-82 ◽  
pp. 581-584 ◽  
Author(s):  
Li Ang Song ◽  
Li Xin Cao ◽  
Ge Su ◽  
Wei Liu ◽  
Hui Liu ◽  
...  
Keyword(s):  
Diffuse Reflectance Spectroscopy ◽  
Cost Effective ◽  
Outer Diameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Phases ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Inner Diameter

Titanium based nanotubes (8-12nm outer diameter and 4-6nm inner diameter) were successfully fabricated by a simple and cost-effective hydrothermal method. The nanotube-like amorphous phases TNT(Na) and TNT(H) were obtained with different post treatment. The samples were characterized by means of high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), selected area electron diffraction (SAED), energy dispersive X-ray spectrum (EDS) and UV-Vis diffuse reflectance spectroscopy (DRS). The photocatalytic activities of the nanotubes were evaluated using photo-oxidation of methyl orange.

Preparation of Chrysotile Nanotubes under Hydrothermal Condition

2011 ◽  
Vol 284-286 ◽  
pp. 688-691 ◽  
Author(s):  
Yang Feng Huang ◽  
Ye Bin Cai ◽  
Hao Liu
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Condition ◽  
Xrd Analysis ◽  
Outer Diameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure And Morphology ◽  
Transmission Electron ◽  
Inner Diameter ◽  
Temperature And Pressure

In a neutral environment, Chrysotile nanotubes have been synthesized by hydrothermal method, with MgO and SiO2powder as the starting materials. X-Ray Diffraction(XRD), Scanning Electron Microscopy(SEM), Transmission Electron Microscopy(TEM) are used to characterize the crystal structure and morphology of the as-prepared samples. We found that the diameter of Chrysotile is uniform. Their outer diameter is about 30~50 nm and the inner diameter is about 6~8 nm. The length of them is a few hundred nanometers. The XRD analysis indicates that the as-prepared Chrysotile is a Rhombohedral structures. The results of HRTEM and SAED showed that the {006} planes of serpentine roll up along the [600] direction to form the tubular structure. In addition, the curves of temperature and pressure with time showed that the water might participate in the reaction.

Preparation and Optoelectronic Properties of In2O3 Microtubes

2014 ◽  
Vol 936 ◽  
pp. 123-126
Author(s):  
Shuai Chen ◽  
Yun Ze Long ◽  
Hong Di Zhang ◽  
Shu Liang Liu ◽  
Ling Zhi Liu ◽  
...  
Keyword(s):  
Uv Light ◽  
Optoelectronic Properties ◽  
Outer Diameter ◽  
X Ray Diffraction ◽  
Visible Spectroscopy ◽  
Strong Response ◽  
X Ray ◽  
Inner Diameter ◽  
Uv Visible ◽  
Scanning Electron

Ultrathin indium oxide (In2O3) microtubes were successfully fabricated by electrospinning, magnetron sputtering and followed calcination. The hollow In2O3tubes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-visible spectroscopy. Outer diameter of the microtubes was in the range of 700-900 nm, and inner diameter was about 400-600 nm. Optoelectronic properties of the In2O3tubes were investigated by irradiation of UV light with different wavelengths (254, 308 and 365 nm). It was found that the In2O3microtubes had a fast and strong response to UV irradiation.

scholarly journals Catalytic growth of carbon nanotubes with large inner diameters

2005 ◽  
Vol 70 (2) ◽  
pp. 277-282 ◽  
Author(s):  
JU. Yan ◽  
LI.YI. Feng ◽  
Ren Zhong
Keyword(s):  
Carbon Nanotubes ◽  
Sodium Carbonate ◽  
Reaction System ◽  
Outer Diameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
Toxic Material ◽  
Transmission Electron ◽  
Growth System ◽  
Inner Diameter

Carbon nanotubes (2.4 g/g catalyst), with large inner diameters were successfully synthesized through pyrolysis of methane on a Ni-Cu-Al catalyst by adding sodium carbonate into the carbon nanotubes growth system. The inner diameter of the carbon nanotubes prepared by this method is about 20-60 nm, while their outer diameter is about 40-80 nm. Transmission electron microscopy and X-ray diffraction were employed to investigate the morphology and microstructures of the carbon nanotubes. The analyses showed that these carbon nanotubes have large inner diameters and good graphitization. The addition of sodium carbonate into the reaction system brings about a slight decrease in the methane conversion and the yield of carbon. The experimental results showed that sodium carbonate is a mildly toxic material which influenced the catalytic activity of the Ni-Cu-Al catalyst and resulted in the formation of carbon nanotubes with large inner diameters. The growth mechanism of the carbon nanotubes with large inner diameters is discussed in this paper.

Structure of rattlesnake venom lectin determined by single particle high-resolution electron microscopy

1996 ◽  
Vol 54 ◽  
pp. 62-63
Author(s):  
Peter D. Moisiuk ◽  
Daniel R. Beniac ◽  
Ross A. Ridsdale ◽  
Martin Young ◽  
Bhushan Nagar ◽  
...  
Keyword(s):  
High Resolution Electron Microscopy ◽  
Lipid Monolayer ◽  
Outer Diameter ◽  
X Ray Diffraction ◽  
Single Particles ◽  
Crotalus Atrox ◽  
3D Reconstructions ◽  
X Ray ◽  
Rattlesnake Venom ◽  
Covalently Linked

Venom from the rattlesnake Crotalus atrox contains a mixture of enzymes that induce a localized effect leading to hemorrhaging, necrosis and edema. As a member of the crotalid family of snake venoms, Crotalus atrox venom contains a C-type lectin that will agglutinate blood cells in a Ca2+-dependent fashion. The lectin is a hydrophilic protein, consisting of two covalently linked, 135 amino acid residues, identical subunits that are rich in aspartic acid, glutamic acid and lysine. Sequence homology with known carbohydrate recognition domains (CRDs) indicates that rattlesnake venom lectin (RSLV) contains a CRD motif that is not linked to accessory domains. Preliminary X-ray diffraction and sedimentation analysis has indicated that lectin from Crotalus atrox forms decamers composed of two five-fold symmetric pentamers. Single particles of RSVL imaged at – 171°C displayed two distinct orientations on the specimen support (Figure a) following incubation in a crystallization Teflon well, coated with a lipid monolayer consisting of phosphatidylcholine and monosialoganglioside. When lying in an end-on orientation, the lectin exhibited a “pentagonal ring” with an outer diameter of 6.7 nm and an inner hollow core of 1.7 nm. A side orientation was also seen, whereby a thickness of 5.8 nm was measured for the lectin. Image processing of 2280 single particles placed in 100 classes (Figure b) led to 3D reconstructions of RSVL (Figure c). Density limited 3D reconstructions showed the lectin to be made of two five-fold symmetrical rings covalently linked between the five subunits that constitute each ring of this homodimer. These results are consistent with sedimentation and preliminary X-ray diffraction analysis on the shape of RSVL and provide the framework for structural verification by 2D electron crystallography.

The study of the elastic deformation of a flexible wheel by a cam wave generator

2020 ◽  
Vol 65 (1) ◽  
pp. 51-58
Author(s):  
Sava Ianici
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Finite Element ◽  
Elastic Deformation ◽  
Theoretical Study ◽  
Elastic Field ◽  
The Finite Element Method ◽  
Elastic Deformations ◽  
Wave Generator ◽  
Two Stages

The paper presents the results of research on the study of the elastic deformation of a flexible wheel from a double harmonic transmission, under the action of a cam wave generator. Knowing exactly how the flexible wheel is deformed is important in correctly establishing the geometric parameters of the wheels teeth, allowing a better understanding and appreciation of the specific conditions of harmonic gearings in the two stages of the transmission. The veracity of the results of this theoretical study on the calculation of elastic deformations and displacements of points located on the average fiber of the flexible wheel was subsequently verified and confirmed by numerical simulation of the flexible wheel, in the elastic field, using the finite element method from SolidWorks Simulation.

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