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Now showing items 1 - 14 of 14


    Disclosed are a disposable multi-needle injection needle and a pre-fillable syringe having the injection needle. The injection needle comprises a needle seat (1), a locating structure, a needle fixing piece (9) and a plurality of needles (2); the needle seat (1) comprises a columnar cylinder (5) and a top cover (3), the upper and lower ends of the columnar cylinder (5) are open, the top cover (3) is arranged on the upper end of the columnar cylinder (5) and is provided with a through hole (4); the locating structure is arranged on the top cover (3); the needle fixing piece (9) is located via the locating structure; the needles (2) pass through the needle fixing piece (9) and are fixed on the needle fixing piece (9), the lower ends of the needles (2) stretch into the columnar cylinder (5) via the through hole (4) in order to pierce into an injection storage unit for obtaining the injection, the upper ends of the needles (2) extend upwards with the aim of piercing into skin and completing the injection, the plurality of needles (2) are distributed at intervals, and both the upper end and lower end of each needle (2) are provided with a bevel.
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    Disclosed is a disposable array-type micro injection needle head, which comprises: a lower needle base (3), which is a columnar cylinder of which one end is provided with an opening and the other end is provided with a top cover and which is connected with an injecta reservoir (17); an upper needle base (2), which is arranged above the top cover of the lower needle base (3), and a cavity (15) is formed between the upper needle base (2) and the top cover; a through hole for communicating the columnar cylinder and the cavity (15) is formed on the top cover, and an injecta extracting needle (4) is arranged in the through hole; one end of the injecta extracting needle (4) is communicated with the cavity (15), and the other end is positioned in the columnar cylinder, and injecta is extracted from the reservoir (17) to the cavity (15); at least two needle tubes (1) are arranged on the upper needle base (2), and one end of each needle tube (1) is a needle tip for puncturing and injecting the injecta, and the other end is arranged on the upper needle base (2) and is communicated with the cavity (15). The needle head can be used for the conventional insulin injection pen directly or formed a disposable pre-filling injector by arranging the injecta reservoir (17) in the columnar cylinder. By using a plurality of thin and short needle tubes (1) to inject simultaneously, medicines such as the insulin and the like can be vertically injected beneath the skin of multiple parts of human bodies quickly, painlessly, safely and conveniently without leakage under the condition that skin is not pinched, so the hidden danger of injecting the medicines into muscles is avoided, and the using compliance and therapeutic effect of patients are improved.
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    A 3D silicon microneedle or microknife with a “- ” shape structure, the top of which is a “-” shape structure parallel to the (111) crystal plane of monocrystalline silicon. The “ ”shape structure is a straight line with a narrow width, or a curve in a planar surface or a convex surface. The microneedle or microknife may be solid or hollow. One side or both sides near the “- ”shape structure of the silicon microneedle or microknife or the center thereof is provided with holes which can be of a suitable shape. The holes communicate with an upended triangle groove formed by six (111) planes on the bottom of the silicon microneedle or microknife to form through-holes. The silicon microneedle or microknife is used for drug delivery through the skin, body fluid withdrawing, or the like. Preparation methods are also provided for preparing the above silicon microneedles or microknives.
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    A metal microneedle array, a transdermal delivery patch with the metal microneedle array, and a microneedle transdermal delivery stamp. The metal microneedle array comprises a substrate (1) and at least one metal sheet (2). The substrate (1) is a solid plate, a solid cylindrical body or a hollow cylindrical body, and has an operation surface in a plane or curved surface shape. The metal sheet (2) is fixed on the substrate (1). Multiple integral microneedles (3) spaced to each other are formed on at least one edge of the metal sheet (2). Each microneedle (3) has a free end and a fixed end connected to the metal sheet (2). A structure of the free end of the microneedle (3) is a needle point (4). The metal sheet (2) is embedded in the operation surface, and at least one part of the microneedle (3) protrudes over the operation surface to form a preset angle with the operation surface. The microneedles (3) in the microneedle array have good consistency, and the manufacturing process of the microneedle array is simplified, and flexibility of the structure design and application is good.
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  • Study on interfacial reaction of Ti/AlN by SIMS, RBS and XRD

    Yue, Ruifeng   Wang, Yan   Wang, Youxiang   Chen, Chunhua  

    A 200 nm Ti film was deposited on a polished AlN ceramic substrate at 200degC by electron beam evaporation and then annealed under high vacuum conditions. The MCs +-SIMS technique (detecting MCs + secondary ions under Cs + primary ion bombardment, where M is the element to be analysed), RBS and X-ray diffraction (XRD) measurements were employed to probe the solid interfacial reaction between Ti and AlN from 200degC to 850degC, and the variation of interfacial composition distribution with annealing temperature and time was given. Ternary aluminides were discovered and the formation and development of the aluminides were observed in the interfacial region. The results indicate that the MCs +-SIMS technique is an effective method to study the interfacial reaction between metal and ceramic
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  • SIMS study on the initial oxidation process of AlN ceramic substrate in the air

    Yue, Ruifeng   Wang, Yan   Wang, Youxiang   Chen, Chunhua  

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  • N-type B-S co-doping and S doping in diamond from first principles

    Tang, Lin   Yue, Ruifeng   Wang, Yan  

    The S-doped diamond and B-S co-doped diamond at different concentrations were investigated by the density functional theory (DFT) to explore the possibility to achieve effective and shallow donors in diamond. We found for the first time that the Valence Band maximum (VBM) and the Intermediate Band (IB) minimum of B-S co-doped diamond are located at the same kappa-point Gamma, which is quite different from the indirect energy gap of S-doped diamond and pure diamond. Although the simulated ionization energy of B-S defect is deeper than that of S defect, the impurities formation energy is much lower than that of S defect. It suggests that the introduction of B help improve the solubility of S in diamond. Besides, the electron effective mass of IB of B-S co-doped diamond is much smaller than that of the S-doped diamond, which may lead to conductivity promotion for diamond. Comparison of the density of states in both cases, it is found that the S-3p states are responsible for conduction band, as well as the B-2p states of B-S co-doped diamond have a little contribution to its conduction band. It can conclude that with the assistance of B, S is a suitable shallow donor impurity in diamond. (c) 2018 Elsevier Ltd. All rights reserved.
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  • Physics-based spice model on the dynamic characteristics of silicon carbide Schottky barrier diode

    Zhou, Xintian   Wang, Yan   Yue, Ruifeng   Dai, Gang   Li, Juntao  

    Silicon carbide Schottky barrier diodes (SiC SBDs) are poised to replace silicon PIN diodes as a new choice for the high power and high frequency applications. However, SiC SBDs suffer from ringing which may induce additional power losses when applied in chopper circuit, regarded as the interaction among the depletion capacitance, depletion resistance, parasitic stray inductance and series resistance. The existing SiC SBD models generally treat the resistances as constants and ignore the influence of the MOS, which deviate the switching commutation process significantly on the ringing frequency and amplitude. In this study, a more accurate Spice model of SiC SBD has been developed in which voltage dependent non-linear depletion capacitance and resistances are all considered in the transient analysis based on semiconductor physics, while the Miller capacitance of the MOS performing as a switch in the circuit is also taken into account. The improved model and analysis are validated by the better agreement with the experiments compared with the existing models on the dynamic characteristics.
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  • Monolithic uncooled 8x8 bolometer arrays based on poly-SiGe thermistor

    Yue, Ruifeng   Dong, Liang   Liu, Litian  

    This paper presents a monolithic uncooled 8 x 8 bolometer array with polycrystalline silicon-germanium (poly-SiGe) thermistors as active elements. The polySiGe films are deposited by ultrahigh vacuum vapor deposition (UHV/CVD) system and the dependence of the temperature coefficient of resistance (TCR) on annealing temperature has been investigated. To decrease the thermal conductance of the bolometer, the poly-SiGe thermistor was formed on a four leg suspended microbridge. The improved porous silicon micromachining techniques described here enable the integration of the bolometer array with the MOS readout circuitry. The measurements and calculations show that the mean responsivity is 1.07 x 10(4) V/W with an uncorrected uniformity of 10.5% and a thermal response time of 10.5 ms, and the detectivity of 3.75 x 10(8) cm Hz(1/2)/W is achieved at a chopping frequency of 30 Hz and a bias voltage of 5 V.
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  • Novel micromachined uncooled infrared detector employing a-Si:H TFT as thermosensitive element

    Dong, Liang   Liu, Litian   Yue, Ruifeng  

    A novel micromachined uncooled infrared (IR) detector based on hydrogened amorphous silicon (a-Si:H) thin film transistor (TFT) as thermosensitive element is proposed for the first time. It utilizes the high temperature dependence of the drain current induced by the influences of temperature variation on the effective carrier mobility in channel and on the threshold voltage. An IR resonance cavity between absorber and the gate electrode improving the IR absorptivity and a microbridge providing a low thermal conductance are designed. The differential amplifier whose input pair is two identical TFTs; of which one is shielded to the IR while the other is unshielded; can not only amplify the voltage signal that is equivalent to the drain current variation but also simultaneously compensate the self-heating effect. Using PSPICE simulator; the responsivity calculated is about 4.1 mV/K at room temperature.
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  • 4H-SiC Trench MOSFET With Floating/Grounded Junction Barrier-controlled Gate Structure

    Zhou, Xintian   Yue, Ruifeng   Zhang, Jian   Dai, Gang   Li, Juntao   Wang, Yan  

    A novel silicon carbide (SiC) trench MOSFET with floating/grounded junction barrier-controlled gate structure (FJB-MOS/GJB-MOS) is presented and investigated utilizing Sentaurus TCAD simulations. The split P+ region introduced beneath the trench could better shield the gate oxide from the high electric field in the blocking mode, leading to an enhancement in the breakdown voltage while without significant degradation of other characteristics. As a result, the FJB-MOS with floating P+ shielding exhibits a higher figure of merit related to the breakdown voltage and the specific on-resistance (V-BR(2)/R-ON,R-sp), which is improved by 15% and 49%, respectively, with comparison to those of the state-of-the-art double-trench MOSFET and L-shaped gate trench MOSFET. In terms of the GJB-MOS with grounded P+ shielding, it shows great advantage in reducing the switching losses thanks to the lower specific gate-drain charge Q(gd,sp) and is more conductive to high frequency applications. Additionally, the formation of the P+ region is aided by the Sentaurus Process and the processing implementation of the proposed structure is discussed.
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  • Design, simulation and fabrication of electrowetting-based actuators for integrated digital microfluidics

    Wu, Jiangang   Yue, Ruifeng   Zeng, Xuefeng   Kang, Ming   Wang, Zheyao   Liu, Litian  

    Electrowetting-on-dielectric (EWOD) is a promising method for manipulating tiny amounts of liquids. However, the miniaturization and the monolithic integration become the great challenges to improve the EWOD applications in actual lab-on-a-chip systems. In this paper, we present an IC-compatible digital microfluidic actuator, which uses silicon as the substrate and the thermally grown SiO2 film on heavily phosphorus-doped poly-silicon microelectrodes as the high quality dielectric layer. The fundamental EWOD operations, such as the droplet transportation, division, creation, and mergence, are numerically analyzed by using the computational fluidic software, CFD-ACE+. The simulation results of transportation and division show that it is an antinomy to select the gap height between two plates for improving respective performances. A tradeoff value of the gap height of 133 mu m is ultimately used to implement the fundamental operations with one actuator. In experiments, all above operations are successfully achieved in air by applying 70 V voltages. Owing to the IC-compatible fabrication, the integration with peripheral circuits is technically feasible to achieve a miniaturized microfluidics.
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  • A heterojunction-based SiC power double trench MOSFET with improved switching performance and reverse recovery

    Yang, Tongtong   Wang, Yan   Yue, Ruifeng  

    In this paper, a heterojunction-based SiC double trench MOSFET (HJ-DTMOS) is proposed to improve its switching performance and the reverse recovery characteristic. In the HJ-DTMOS, a nthornp polysilicon junction is introduced in both the gate trench and the source trench. For the source trench, the heterojunction formed by the p polysilicon layer and drift silicon carbide layer functions as a body diode in parallel with the device which shows a significant reduction in term of the reverse recovery charge and the on-state voltage. The nthornp junction in the gate trench introduces an additional depletion capacitance between the gate electrode and the drain electrode, which efficiently reduces the total Cgd, thus reducing the switching loss of the HJ-DTMOS. Simulation results show that the proposed new device is preferred in high-frequency and high-efficiency power applications.
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  • Investigations on the Degradation of 1.2-kV 4H-SiC MOSFETs Under Repetitive Short-Circuit Tests

    Zhou, Xintian   Su, Hongyuan   Wang, Yan   Yue, Ruifeng   Dai, Gang   Li, Juntao  

    The long-term operational reliability of silicon carbide (SiC) MOSFETs needs to be further verified before they could replace silicon counterparts in power applications. In this paper, the failure mechanism of commercial 1.2-kV SiC MOFSETs under repetitive short-circuit (SC) tests has been investigated. Relatively low stress defined as low bias voltage and short SC duration is imposed on the devices, eliminating the effect of gate oxide degradation and metal deterioration. The generation of hot holes in the oxide is confirmed by the charge pumping experiments and measurements on the transfer characteristics of the stressed devices during the tests. Electrothermal simulation results demonstrate that the trapped holes are located above the channel region due to the high local impact ionization generation rate and electric field. Besides, the additional positive electric field to the channel makes V-th decrease and I-dss increase, which are consistent with the experimental results. What is more, the trapped holes get indeed released, as the ambient temperature increases when the stress is removed.
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