A low-energy single-ended duobinary transceiver is proposed for the point-to-point DRAM interface with an energy efficiency of 0.56 pJ/bit at 7 Gb/s. The transmitter power is reduced by decreasing the signal swing of transmission channel to 80 mV and replacing the multiplexer and the binary output driver in the transmitter by a duobinary output driver. A trans-impedance amplifier (TIA) is used at the receiver end of transmission channel. The TIA works as a receiver termination and also amplifies the input signal for subsequent processing. Analysis of the feedback loop delay and the nonlinearity of the TIA shows that they do not impose serious problems. The TIA output signal is applied to a duobinary-to-NRZ converter, which is implemented by using a direct feedback 1-tap DFE circuit with a tap-coefficient of 1.0. The reference voltage of the duobinary-to-NRZ converter is calibrated automatically to enable a small-swing signaling. The proposed transceiver chip in a 65 nm CMOS process works at 4.5 Gb/s with a 3" FR4 microstrip line, and at 7 Gb/s with a 0.6" FR4.
A 16.8 Gbps/channel single-ended transceiver for SiP-based DRAM interface on silicon carrier channel is proposed in this paper. A transmitter, receiver, and channel are all included in a single package as SiP. A current mode 4:1 MUX with 1-tap feed-forward equalizer (FFE) is used as a serializer, and this 4:1 MUX uses 25% duty clock to prevent short circuit current when consecutive 2-phase clocks overlap. Additionally, an open drain output driver with asynchronous type 1-tap FFE is used in the transmitter. Because of its small physical size, a common mode variation of Si-carrier channel from process variation is more serious than that of conventional PCB. This common mode variation degrades bit error rates (BER) at single-ended signaling. To obtain effective single-ended signaling on Si-carrier channel, a source follower-based continuous time linear equalizers and self- VREF generator with training algorithm on the receiver are proposed. An implemented Si-carrier channel uses meshed layer as a reference to reduce insertion loss. A BER less than 1e-12 is achieved in 65 nm CMOS and the power efficiency of the transceiver is 5.9 pJ/bit with 120 Ω terminations at each transceiver side.
Impedance spectroscopy has been widely employed in order to monitor the hydration phenomena which reflect the electrical conduction along the porous paths whose ionic features are easily discerned from the electrode polarization. The microstructural changes influence the impedance features composed of resistors, capacitors, and inductors, through their intermixed connections involving series, parallel or, both. Unlike the application of impedance spectroscopy to the bulk phenomena, the three-point impedance spectroscopy can be exploited towards the rational separation of a specific electrode from the remaining system through the multipoint electrode configuration in order to localize the corrosion responses of the electrode under interest. The effects of the electrode configuration are investigated in order to establish the methodology on the corrosion monitoring in reinforcement materials in building materials. The current work chooses Ni/Ti-Based and Fe-Based shape memory alloys as model systems in monitoring the corrosion phenomena encountered in construction applications. The shape memory alloys are mixed with the cement-based materials with the aim to providing self-healing functions in association with the detrimental cracks in smart composite materials. In particular, the Ni-Ti and Fe-Si shape memory alloys are subjected to corrosion environments in everyday and hostile conditions. The conventional potentiostat approaches are performed in parallel, in order to prove the applicability of the multipoint impedance spectroscopy in the electrochemical applications involving nano-materials. The ramifications of multi-point impedance spectroscopy are discussed towards corrosion-specific monitoring in functional shape memory alloys which is recommended as one of powerful next-generation building materials.
Recently, a single or multi processor system uses the hierarchical memory structure to reduce the time gap between processor clock rate and memory access time. A cache memory system includes especially two or three levels of caches to reduce this time gap. Moreover, one of the most important things In the hierarchical memory system is the hit rate in level 1 cache, because level 1 cache interfaces directly with the processor. Therefore, the high hit rate in level 1 cache is critical for system performance. A victim cache, another high level cache, is also important to assist level 1 cache by reducing the conflict miss in high level cache. In this paper, we propose the advanced high level cache management scheme based on the processor reuse information. This technique is a kind of cache replacement policy which uses the frequency of processor's memory accesses and makes the higher frequency address of the cache location reside longer in cache than the lower one. With this scheme, we simulate our policy using Augmint, the event-driven simulator, and analyze the simulation results. The simulation results show that the modified processor reuse information scheme(LIVMR) outperforms the level 1 with the simple victim cache(LIV), 6.7% in maximum and 0.5% in average, and performance benefits become larger as the number of processors increases.
Liquid hydrogen has been studied for use in vehicles. However, during the charging process, liquid hydrogen is lost as gas. Therefore, it is necessary to estimate and reduce this loss and simulate the charging process. In this study, the initial charging process of a vehicle liquid hydrogen tank under room temperature and atmospheric pressure conditions was numerically investigated. A transient thermal-fluid simulation with a phase-change model was performed to analyze variations in the volume, pressure, mass flow rate, and temperature. The results showed that the process could be divided into three stages. In the first stage, liquid hydrogen was actively vaporized at the inner wall surface of the storage tank. The pressure increased rapidly, and liquid droplets were discharged into the vent pipe during the second stage. In the third stage, the mass flow rates of liquid and hydrogen gas at the outlet showed significant fluctuations, owing to complex momentum generated by the evaporation and charging flow. The temperatures of the inner and outer walls, and insulation layer, decreased significantly slower than that of the gas region because of its high heat capacity and insulation effect. The optimal structure should be further studied because the vortex, stagnation, and non-uniform cooling of the wall occurred near the inlet and outlet pipes.
A 16.8Gbps/channel single ended transceiver for SiP based DRAM interface on silicon carrier channel is presented. A transmitter, receiver, and channel are all included in a single package. On the transmitter, 1 tap FFEs are used in 4:1 MUX and in output driver. On the receiver, source follower based CTLEs and self Vref generator are used for obtaining effective single ended signaling on Si-carrier channel. A BER that is less than 1e-12 is achieved in 65nm CMOS. The power efficiency of the transceiver is 5.9pJ/bit with 120Ω terminations at each transceiver side.
Atomic layer deposition offers a 3-diemensional conformal deposition of materials along with the atomic scale control on thickness control at the low-temperature regimes. Metal oxide materials can be exploited to the nanoscale coating onto the underlying materials. The cellulose materials offer ecofriendly applications which can be designed to the versatile fabric products or equivalents. The integration of ALD onto the cellulose materials can be tailored towards stretchable electronics which allows the flexible deformation unlike the previous rigid applications based glass or silicon technologies. Zinc oxide (ZnO) is chosen to be a coating material characteristic of semiconducting conduction. The zinc oxide thin films are deposited through the atomic layer deposition of diethyl zinc (DEZ) water. The ALD-based zinc oxide thin films are characterized by a multitude of physical/chemical probing tools: X-ray photoelectron microscopy for bonding and composition information, X-ray diffraction for crystallinity, atomic force microscopy and scanning electron microscopy for morphological characterization, and dc/ac-based electrical characterizations. Cellulose and its derivatives are ecofriendly materials due to superior features tensile strength and toughness contrary to the pollution-inducing thermoplastic materials. The beneficial features are applied to building materials, pharmaceuticals, cosmetics, and foods. The cellulose-based materials are chemically versatile and artificially controlled. The current work exploits two specific features, i.e. i) the dissolution feature of cellulose acetate in acetone and the OH terminated features of cellulose materials. The flexible cellulose materials are prepared using a 3-dimensional printing concept: the cellulose acetate materials are dissolved intro acetone and the subsequent removal of acetone allows the flexible solid formation of cellulose materials after extrusion through high-resolution 3D-printing. The mesh-typed specimens are subjected to simultaneous measurements on mechanical deformation and electrical resistance. The electrical/dielectric monitoring is performed in the two-point electrode configuration involving ac and dc characterizations. In particular, the frequency-dependent impedance spectroscopy provides a wealth of information on bulk- and/or electrode-responses as a function of mechanical deformation. The applicability of ALD to cellulose materials is discussed in terms of mechanical robustness and electrical reliability required in high-performance stretchable electronics.
In this work, loess-based materials were designed based on a multicomponent composite materials system for ecofriendly natural three-dimensional (3D) printing involving quick lime, gypsum, and water. The 3D printing process was monitored as a function of gypsum content; in terms of mechanical strength and electrical resistance, in the cube-shaped bulk form. After initial optimization, the 3D printing composition was refined to provide improved printability in a 3D printing system. The optimal 3D fabrication allowed for reproducible printing of rectangular columns and cubes. The development of 3D printing materials was scrutinized using a multitude of physicochemical probing tools, including X-ray diffraction for phase identification, impedance spectroscopy to monitor setting behaviors, and mercury intrusion porosimetry to extract the pore structure of loess-based composite materials. Additionally, the setting behavior in the loess-based composite materials was analyzed by investigating the formation of gypsum hydrates induced by chemical reaction between quick lime and water. This setting reaction provides reasonable mechanical strength that is sufficient to print loess-based pastes via 3D printing. Such mechanical strength allows utilization of robotic 3D printing applications that can be used to fabricate ecofriendly structures.
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