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

Freedom of design, mass customisation, waste minimisation and the ability to manufacture complex structures, as well as fast prototyping, are the main benefits of additive manufacturing (AM) or 3D printing. A comprehensive review of the main 3D printing methods, materials and their development in trending applications was carried out. In particular, the revolutionary applications of AM in biomedical, aerospace, buildings and protective structures were discussed. The current state of materials development, including metal alloys, polymer composites, ceramics and concrete, was presented. In addition, this paper discussed the main processing challenges with void formation, anisotropic behaviour, the limitation of computer design and layer-by-layer appearance. Overall, this paper gives an overview of 3D printing, including a survey on its benefits and drawbacks as a benchmark for future research and development.

Additive manufacturing (3D printing): A review of materials, methods, applications and challenges

A strain sensor has been fabricated from a polymer nanocomposite with multiwalled carbon nanotube (MWNT) fillers. The piezoresistivity
of this nanocomposite strain sensor has been investigated based on an improved three-dimensional (3D) statistical resistor network
model incorporating the tunneling effect between the neighboring carbon nanotubes (CNTs), and a fiber reorientation model. The
numerical results agree very well with the experimental measurements. As compared with traditional strain gauges, much higher sensitivity
can be obtained in the nanocomposite sensors when the volume fraction of CNT is close to the percolation threshold. For a small
CNT volume fraction, weak nonlinear piezoresistivity is observed both experimentally and from numerical simulation. The tunneling
effect is considered to be the principal mechanism of the sensor under small strains.

Tunneling effect in a polymer/carbon nanotube nanocompositestrain sensor

A review : On the development of low melting temperature Pb-free solders

Composite lead-free solders, containing micro and nano particles, have been widely studied. Due to grain boundary drag or Zener drag, these particles can refrain the solder microstructure from coarsening in services, especially for Cu6Sn5, Ag3Sn intermetallic compounds and the β-Sn phases. Due to dispersion hardening or dislocation drag, the mechanical properties of the composite solder alloys were enhanced significantly. Moreover, these particles can influence the rate of interfacial reactions, and some particles can transform into a layer of intermetallic compound. Wettability, creep resistance, and hardness properties were affected by these particles. A systematic review of the development of these lead-free composite solders is given here, which hopefully may find applications in microbumps to be used in the future 3D IC technology.

Structure and properties of lead-free solders bearing micro and nano particles

Lithium niobate (LiNbO3) single crystals are used as a promising piezoelectric material for high temperature sensors owing to its superior electromechanical coefficients and high frequency operation. The selection of materials and techniques for LiNbO3 die-attach aiming for the service temperature up to 300 °C encounters many objectives and practical considerations, where the processing temperature should be kept below 450 °C due to the decomposition of the die. Among the few candidates of lead-free solders exist in this temperature range, gold-germanium (Au-12 wt. % Ge) eutectic solder has shown promising characteristics. Therefore, in the current study, LiNbO3 die-attach to Hastelloy substrate with this solder was investigated. The mechanical properties of the corresponding assemblies were examined by a die-shear tester and the reliability of the joints has been assessed after thermal aging and thermal shock treatments at 300 °C.

LiNbO 3 die-attach with Au-Ge eutectic solders

By establishing and exploring a numeric model of an acoustofluidic device driven by a piezoelectric plate transducer, we discovered simple and distinct vibrational patterns with high displacement amplitudes for a lateral vibrational mode of the transducer plate. With the design based on a numerically optimized chip-geometry for this particular lateral mode, we fabricated high-performant chips enabling rapid and accurate particle focusing, where the acoustic energy density is exceeding 100 J/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> at actuation frequencies around 540 kHz, while heat generation remains low. We excite higher order harmonics leading to multiple separate lines of particles along the channel. With the custom-made chip holder featuring integrated fluid connections and transducer support, we are moreover able to swiftly mount microfluidic chips directly after dicing without any further preparation. 

Utilizing Lateral Plate Transducer Modes for High Quality Acoustofluidics in Silicon-Based Chips

In this paper, we report the integration of a non-CMOS transition metal oxide composite thin film with a high negative temperature coefficient resistance (NTCR) of 3.8 %/K on a silicon nitride membrane for uncooled infrared microbolometer working in the long wavelength infrared (LWIR) region. The NTC thin film is fabricated by a chemical solution deposition process requiring high crystallization temperature (>750°C). Different micromachined silicon-nitride membrane-supported bolometers (1, 2×2 and 4×4 pixels) with a 170×170 µm2 pixel size are successfully fabricated and packaged in a vacuum-shielded TO housing. The fabricated devices exhibit a typical noise equivalent temperature difference (NETD) value down to 15 mK×Hz-1/2 and a high specific detectivity characteristic of 1.4×108 cm×Hz1/2×W-1.

Integration of a High Temperature Transition Metal Oxide NTC Thin Film in a Microbolometer for LWIR Detection

As the most promising candidate for heterogeneous and 3D integration, Copper (Cu)-based interconnect are gaining prominence, due to superior characteristics (e.g., low resistivity, high electromigration resistance, high-temperature performance and low cost). Cu pillars allow for finer pitch, by providing higher control of bump diameter and height when compared to solder bumps. Flip chip bonding of Cu pillars can be conducted directly through thermocompression bonding or indirectly by employing solder caps. While the former imposes high temperature and pressures on the interface, the latter face reliability issues due to the formation of brittle intermetallic and thermal mismatches. Correspondingly, in this study, an alternative approach for solder-free Cu pillar bonding using Cu sinter pastes was investigated. To achieve an all-Cu interconnect between Cu pillars and Cu pads, a recently developed pressure-less Cu sinter paste was used in this study. The electrical and mechanical properties of the flip-chip bonded Cu pillars using pressure-less Cu paste were further compared with a pressure-assisted Cu paste. The long-term reliability of the bonded samples was assessed using thermal cycling tests.

Ali Roshanghias

Papers

LiNbO 3 die-attach with Au-Ge eutectic solders

Utilizing Lateral Plate Transducer Modes for High Quality Acoustofluidics in Silicon-Based Chips

Integration of a High Temperature Transition Metal Oxide NTC Thin Film in a Microbolometer for LWIR Detection

A Comparison Between Pressure-less and Pressure-assisted Cu Sintering for Cu Pillar Flip Chip Bonding

D2d Ultra-Fine Pitch, Direct Copper Bonding with Protruded and Recessed Topographies