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In this paper, the effect of using pre-consumer PVC scraps on static and long-term mechanical properties is stud- ied. The degradation characteristics of mixing virgin PVC with crushed pre-consumer and PVC pipe scraps are analyzed using various tools including Gel Permeation Chromatography (GPC), Thermogravimetric Analysis (TGA), X-ray fluores- cence (XRF) and Fourier Transform Infrared (FTIR) spectroscopy. The variation of static mechanical properties as a func- tion of adding pre-consumer PVC pipe scraps is investigated using the degradation analyses of recycled PVC scraps. In addition, fatigue tests are executed to evaluate the long-term durability of blending virgin PVC and recycled PVC scraps, and the fracture surface is investigated in detail to reveal the variation of the fracture mechanisms.

The somatic cell count (SCC) is one of the international standards for monitoring milk quality, and it is a useful indicator of mastitis. The current reference method for determining the SCC in raw milk is direct microscopic analysis, but this method requires well-trained staff to maintain its accuracy and reproducibility. To overcome these inconveniences, we developed a portable system (the C-reader system) that utilizes the capillary flow of a microfluidic chamber by surface modification of the hydrophilicity. The microfluidic technology of disposable microchips allows for low consumption of reagents, and a combination of ready-to-use reagents makes the daily work easier. The repeatability test of the C-reader using 10 composite bovine milk samples satisfied the recommended values for SCC equipment. In addition, an acceptable accuracy level of the natural logarithmic-transformed SCC [ln(SCC/1,000): +/- 0.059 to 0.112] was achieved using composite raw milk samples and various somatic cell standard solutions from the American Eastern Laboratory and the Korean National Veterinary Research and Quarantine Service. After testing 875 composite milk samples, the C-reader showed a high correlation coefficient (R2 = 0.935 to 0.964) and a low mean difference value in log-transformed SCC (-0.088 to 0.004) compared with 3 automatic commercialized somatic cell counters (Fossomatic 4000, Somacount 150, and Somascope). In conclusion, the C-reader system is a new, easy-to-use automatic on-farm method with acceptable repeatability and accuracy for measuring SCC in large dairies and smaller laboratories.

We have tried to find the most suitable conditions for the deposition process of silicon carbide thin films as a material for MEMS techniques. We have also studied its application to semiconductor processes. To do this, we have tried to fabricate several dimensions of cantilevers with these silicon carbide thin films. High quality silicon carbide thin films are grown by metal-organic chemical vapor deposition (MOCVD). This process employs single molecular precursors such as diethylmethylsilane (DEMS), 1,3-disilabutane (DSB) at a pressure of 1 × 10−3 Pa and a growth temperature in the range of 700–1000 °C. Two fabrication methods are tested for initial fabrication of cantilevers. First, deposit SiC thin films on Si based atomic force microscopy (AFM) cantilevers. Second, used the lift-off process. To get three-dimensional cantilever-shaped SiC thin films, moreover, we chemically etched silicon substrate with strong alkaline solution such as TMAH at 80 °C. In addition, a high resolution of probe tips on the cantilevers was achieved using electron-beam deposition in a carbon atmosphere.

Microcapsules with good mechanical stability were prepared using an appropriate mixture of alginate and acrylic terpolymer. It was found from the microscopic observation that the microcapsules had a porous structure with interconnected pores, with a size of 50-150 nm. The results of the permeability experiment of microcapsules using FITC-dextrans showed that the capsule had a molecular mass cut-off of 120 kDa. The hepatocytes encapsulated in both alginate and acrylic terpolymer with gelatin and PVA rapidly aggregated in the core. The aggregated cells showed high albumin synthesis and ammonia removal, suggesting good metabolic function.

The influence of the mixture concentration on densification of Fe-Cr, Fe-Mo, and Ti-Cu compacts during solid state sintering were investigated. The hypothesis was put forward before that only S and V shaped curves for concentration dependencies of densification exist as a result of solid phase sintering of mixtures. It was shown, in this paper, that the above idea on the existence only two types of the plots was correct. These curve shapes can be explained on the basis of diffusion interaction of metals, applying the multiparticle model of a two component compact.

An attempt was made of using a liquid phase sintered alloy, which will be a liquid phase coexisting with solid particles at the bonding temperature, as an interlayer for bonding metals. With an aim of revealing the fundamental features of this modified TLP bonding, investigated were the kinetics concerned with the isothermal solidification process and the growth of solid particles in Fe-4.5wt%P and Fe-1.16wt%B interlayers for bonding pure iron. The movement of the bond interface was linearly dependent on t1/2 with higher slope than expected in the normal TLP bonding. The higher slope is attributed to the contribution of the solid particles distributed in the interlayer. The solid particles have shown no growth. However, when pure Fe particles are allowed to coexist with the liquid of equilibrium composition, they grows very rapidly. Discussion was made on the growth kinetics of the pure Fe particles.

We report on our work on the double electron layer tunneling transistor (DELTT), based on the gate-control of two-dimensional -- two-dimensional (2D-2D) tunneling in a double quantum well heterostructure. While previous quantum transistors have typically required tiny laterally-defined features, by contrast the DELTT is entirely planar and can be reliably fabricated in large numbers. We use a novel epoxy-bond-and-stop-etch (EBASE) flip-chip process, whereby submicron gating on opposite sides of semiconductor epitaxial layers as thin as 0.24 microns can be achieved. Because both electron layers in the DELTT are 2D, the resonant tunneling features are unusually sharp, and can be easily modulated with one or more surface gates. We demonstrate DELTTs with peak-to-valley ratios in the source-drain I-V curve of order 20:1 below 1 K. Both the height and position of the resonant current peak can be controlled by gate voltage over a wide range. DELTTs with larger subband energy offsets ({approximately} 21 meV) exhibit characteristics that are nearly as good at 77 K, in good agreement with our theoretical calculations. Using these devices, we also demonstrate bistable memories operating at 77 K. Finally, we briefly discuss the prospects for room temperature operation, increases in gain, and high-speed.

We describe the first demonstration of dual-side electron beam lithography in achieving independent submicron gating in double quantum well devices. The technique utilizes the epoxy-bond and stop-etch process to remove the substrate material which allows the backside gates to be placed in close proximity (less than 1 m) to the frontside gates. The use of electron beam lithography allows both the definition of submicron features and the precise alignment of the front and back features to each other. We have applied this technique to the fabrication of double quantum point contacts on coupled AlGaAs/GaAs double quantum wells. Low-temperature transport measurements clearly show the formation of coupled, independently controllable mesoscopic structures in each of the two quantum wells.

We demonstrate unipolar complementary circuits consisting of a pair of resonant tunneling transistors based on the gate control of 2D-2D interlayer tunneling, where a single transistor - in addition to exhibiting a welldefined negative-differential-resistance can be operated with either positive or negative transconductance. Details of the device operation are analyzed in terms of the quantum capacitance effect and band-bending in a double quantum well structure, and show good agreement with experiment. Application of resonant tunneling complementary logic is discussed by demonstrating complementary static random access memory using two devices connected in series.

It has been reported that the spin sprayed ferrite film shows better magnetic properties at high frequency than the ferrite by co-firing over 800 /spl deg/C . Besides, there is no limitation to select the substrate materials because it can be processed with low temperature below 100 /spl deg/C. Therefore, we fabricated a film inductor as a passive device for DC-DC converter by a use of spin sprayed Ni-Zn ferrite film on the polyimide layer without insulating layer. After, cover-lay film was laminated on the top of that. Finally, embedded form was completed by via hole process of pad opening. The magnetic properties of Ni-Zn ferrite were 6.0 k gauss of saturation magnetization and 110 of effective permeability. And 1,6 micro H of L, 25 of Q at 5 MHz were measured with spiral 16 turn inductor. The rated current of inductor was measured 897 mA.

We report the fabrication, characterization, and field emission properties of (silicon oxide) SiOx coated thin-multiwalled carbon nanotubes (t-MWNTs). The coated t-MWNTs show improved field emission behavior. Initially, raw t-MWNTs (diameter ∼5–8nm) were functionalized by acid treatment. Using spin on glass as a Si precursor, SiOx was coated on the nanotubes by routine chemical methods. The coated samples were characterized by high resolution transmission electron microscopy (HRTEM), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA) techniques. The HRTEM results show that the local thickness of the coating varies from ∼1to2nm. The FTIR investigations show the formation of nanophases, such as Si–C, Si–O–C, and intercalated Si–O, at the coating/nanotube interface. The TGA reveals that the coating prevents the high-temperature oxidation and degradation of the nanotubes. The field emission characteristics of the coated, functionalized, and raw nanotubes show that the turn-on...

Silicon carbide (SiC) thin films were prepared on Si(100) substrates by high vacuum metalorganic chemical vapor deposition using a single-source precursor at various growth temperatures in the range of 700–1000 °C. The precursor is diethylmethylsilane, and is used without carrier gas. The effects of substrate temperature as well as deposition time on the crystal growth were investigated. The optimum temperature for the formation of high quality polycrystalline SiC thin films was found to be 900 °C on the basis of x-ray diffraction and transmission electron diffraction results. X-ray photoemission spectroscopy shows that SiC films grown at 900 °C have slightly carbon-rich compositions (Si:C=1:1.2) in the surface region, but stoichiometric composition in the bulk. Scanning and transmission electron microscope images show the influence of substrate temperature on the grain size and crystallinity of the films. Large grain sizes and high quality crystallinity can be obtained below 900 °C.

We describe the first demonstration of small-area double electron layer tunneling transistors (DELTTs) fabricated by dual-side electron beam lithography. The DELTT is a planar quantum device which operates by modulating the two-dimensional (2D)-to-2D tunneling between two coupled quantum wells. The fabrication technique utilizes the epoxy-bond and stop-etch process to remove the substrate material which allows the backside gates to be placed in close proximity (less than 1 μm) to the frontside gates. The use of electron beam lithography provides precise alignment of the front and back features to each other. We have applied this technique to the fabrication of DELTTs on coupled AlGaAs/GaAs double quantum wells. Low temperature electrical characterization yields source-drain current–voltage curves that exhibit negative differential resistance with peak-to-valley ratios of up to 8:1. The height and position of the resonant peak varies strongly with gate bias, demonstrating transistor action.