다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

3D printing technology can produce complex objects directly from computer aided digital designs. The technology has traditionally been used by large companies to produce fit and form concept prototypes (‘rapid prototyping’) before production. In recent years however there has been a move to adopt the technology as full-scale manufacturing solution. The advent of low-cost, desktop 3D printers such as the RepRap and Fab@Home has meant a wider user base are now able to have access to desktop manufacturing platforms enabling them to produce highly customised products for personal use and sale. This uptake in usage has been coupled with a demand for printing technology and materials able to print functional elements such as electronic sensors. Here we present formulation of a simple conductive thermoplastic composite we term ‘carbomorph’ and demonstrate how it can be used in an unmodified low-cost 3D printer to print electronic sensors able to sense mechanical flexing and capacitance changes. We show how this capability can be used to produce custom sensing devices and user interface devices along with printed objects with embedded sensing capability. This advance in low-cost 3D printing with offer a new paradigm in the 3D printing field with printed sensors and electronics embedded inside 3D printed objects in a single build process without requiring complex or expensive materials incorporating additives such as carbon nanotubes.

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A Simple, Low-Cost Conductive Composite Material for 3D Printing of Electronic Sensors

A device integration method and integrated device. The method may include the steps of directly bonding a semiconductor device having a substrate to an element; and removing a portion of the substrate to expose a remaining portion of the semiconductor device after bonding. The element may include one of a substrate used for thermal spreading, impedance matching or for RF isolation, an antenna, and a matching network comprised of passive elements. A second thermal spreading substrate may be bonded to the remaining portion of the semiconductor device. Interconnections may be made through the first or second substrates. The method may also include bonding a plurality of semiconductor devices to an element, and the element may have recesses in which the semiconductor devices are disposed. A conductor array having a plurality of contact structures may be formed on an exposed surface of the semiconductor device, vias may be formed through the semiconductor device to device regions, and interconnection may be formed between said device regions and said contact structures.

Three dimensional device integration method and integrated device

A model that predicts the static friction for elastic-plastic contact of rough surfaces is presented. The model incorporates the results of accurate finite element analyses for the elastic-plastic contact, adhesion and sliding inception of a single asperity in a statistical representation of surface roughness. The model shows strong effect of the external force and nominal contact area on the static friction coefficient in contrast to the classical laws of friction. It also shows that the main dimensionless parameters affecting the static friction coefficient are the plasticity index and adhesion parameter The effect of adhesion on the static friction is discussed and found to be negligible at plasticity index values larger than 2. It is shown that the classical laws of friction are a limiting case of the present more general solution and are adequate only for high plasticity index and negligible adhesion. Some potential limitations of the present model are also discussed pointing to possible improvements. A comparison of the present results with those obtained from an approximate CEB friction model shows substantial differences, with the latter severely underestimating the static friction coefficient.

A Static Friction Model for Elastic-Plastic Contacting Rough Surfaces

A method for bonding at low or room temperature includes steps of surface cleaning and activation by cleaning or etching. The method may also include removing by-products of interface polymerization to prevent a reverse polymerization reaction to allow room temperature chemical bonding of materials such as silicon, silicon nitride and SiO2. The surfaces to be bonded are polished to a high degree of smoothness and planarity. VSE may use reactive ion etching or wet etching to slightly etch the surfaces being bonded. The surface roughness and planarity are not degraded and may be enhanced by the VSE process. The etched surfaces may be rinsed in solutions such as ammonium hydroxide or ammonium fluoride to promote the formation of desired bonding species on the surfaces.

Method for low temperature bonding and bonded structure

Recent researches on friction and wear in MEMS were reviewed and discussed in this paper. Friction, a major problem for many micro actuators in MEMS, has been actively investigated based on the results from both scientific instruments and microstructures of practical dimensions. The surface effects influencing the frictional behavior in MEMS were discussed. Based on the proposed differential friction coefficient, the expressions for friction, the friction properties for micro and macro scales were compared. The measures to reduce the friction and wear in MEMS were also discussed.

Friction and wear properties in MEMS

In the trend towards low-cost, high-performance, and miniaturization, a wafer-level vacuum package is developed for micromachined thermoelectric infrared (IR) sensor. An IR sensor wafer and a cap wafer are bonded together in a vacuum chamber using Au-Au thermocompression bonding, where the cap wafer not only protects the floating thermopile structure but also selects IR light for the sensor. The device fabrication and Au-Au thermocompression hermetic bonding process as well as the packaged IR sensor characterization is presented in this paper. Experimental results show that the wafer-level vacuum packaged IR sensor has a four times higher responsivity and detectivity than the IR sensor with atmosphere pressure package, which confirms the IR performance improvement due to vacuum packaging. IR microscope image of the packaged device proved that the Au-Au thermocompression bonding process is compatible to the handling of fragile micromachined thermopile structure. Average leak rate and shear strength are, respectively, 3.9 × 10-9 atm cc/s and 16.709 Kgf, which shows that the Au-Au thermocompression hermetic bonding is suitable for the wafer-level vacuum packaging of micromachined thermoelectric IR sensor.

Wafer-Level Vacuum Packaging of Micromachined Thermoelectric IR Sensors

A wafer-level vacuum package with silicon bumps and electrical feedthroughs on the cap wafer is developed for a microelectromechanical systems (MEMS) resonator device. A MEMS resonator wafer and a cap wafer are bonded together in a vacuum chamber using glass frit bonding. The cap wafer not only provides a vacuum chamber to protect the movable resonator structure and improve the resonant performance but also realizes the redistribution of the electrical feedthroughs by using the silicon bumps. The silicon bumps provide vertical interconnections between the cap wafer and the resonator wafer, which realizes the bonding pads “transferring” from the resonator wafer to the cap wafer. A gold-aluminum eutectic is used to ensure electrical contacts between the cap wafer and the device wafer. The device fabrication and glass frit hermetic bonding process as well as the packaged MEMS resonator characterization are presented in this paper. Experimental results show that the wafer-level vacuum-packaged MEMS resonator results in over 100× higher quality factor (Q) than the resonator vibrating in atmosphere pressure, which confirms the transmission performance improvement due to vacuum packaging. Vacuum inside the package is measured indirectly by measuring the Q of the MEMS resonator inside the package. The experimental results indicate that vacuum about 1 mbar can be sealed in this approach.

Wafer-Level Vacuum Packaging for MEMS Resonators Using Glass Frit Bonding

Design, fabrication and testing of a novel silicon micromachined gyroscope prototype with slots structure are presented. The device structure which we called “slots gyroscope” consists of a proof mass with slots linked up to substrate by suspend springs and is fabricated by silicon–glass bonding and deep reactive ion etching (DRIE). The gyroscope makes use of electrostatic driving and capacitive sensing. As the proof mass used as the movable electrodes is parallel to the plane of fixed driving and sensing electrodes, there is only slide film damping in the driving and sensing mode. The gyroscope can operate at atmospheric pressure due to almost same high quality factor in the sensing direction and driving direction. The experiment result shows that the drive and sense mode resonant frequencies are 460.4 and 549.6 Hz, respectively, and the quality factor of the drive and sense are 102.5 and 106.5, respectively at atmospheric pressure. The scale factor and non-linearity of the micromachined gyroscope are 20 mV/(° s) and 0.56%, respectively at atmospheric pressure.

A novel bulk micromachined gyroscope with slots structure working at atmosphere

This paper presents the design, fabrication and experimental results of a front-etched CMOS compatible micromachined thermopile IR detector. The N-polysilicon/Al thermocouples were embedded in a 2.5 ?m thick SiO2?Si3N4?SiO2 sandwich membrane, and XeF2 front-side isotropic post-etching was adopted to release and thermally isolate the thermopile structure. Due to the isotropy of XeF2 etching, a lot of flexibility was allowed in etching window layout and thermopile structure design. Etching windows in the dielectric absorber area were designed to avoid cutting off the heat transfer path from the absorber to hot junctions, and aluminum strips were patterned in the absorber to ensure the temperature was uniform across the absorber area. Two different thermopile structures, circle and rectangle, were designed and fabricated to investigate detector performance with respect to the thermopile structure. The steady-state behavior of fabricated detectors was anticipated by thermal ANSYS simulation. Due to the fact that the circular structure can get a higher temperature difference between hot and cold junctions, the circular thermopile detector has a quicker response, two times higher responsivity and detectivity than the rectangular thermopile detector. The circular thermopile detector exhibits a responsivity of 102.0 V W?1, a detectivity of 9.2 ? 107 cm Hz1/2 W?1 and a time constant of 16.8 ms, in air at room temperature.

http://iopscience.iop.org/article/10.1088/0960-1317/20/11/115004/pdf

Bin Xiong

Papers

Friction and wear properties in MEMS

Wafer-Level Vacuum Packaging of Micromachined Thermoelectric IR Sensors

Wafer-Level Vacuum Packaging for MEMS Resonators Using Glass Frit Bonding

A novel bulk micromachined gyroscope with slots structure working at atmosphere

Design, fabrication and characterization of a front-etched micromachined thermopile for IR detection