Dip-coating conditions and modifications of lead titanate and lead zirconate titanate films

The modifications of dip-coated lead titanate (PT) and lead zirconate titanate (PZT) films strongly depend on the film thickness and the substrate in addition to the heat-treatment temperature. At 500 to 600 ° C, metastable paraelectric pyrochlore grew on glass plates (amorphous plates) when the thickness of the coated films produced by one coating cycle was below 100 nm, while ferroelectric perovskite formed on crystalline substrates or when thick films were coated on amorphous plates. This tendency is discussed in terms of an inhomogeneous reaction and the epitaxial effect. The perovskite PT films coated on single-crystal SrTiO₃ plate at 700 ° C were strongly oriented to thec-axis.     

Suppression of tin whisker formation on fine pitch connectors by surface roughening

In the electronics industry, lead-free solder processes such as the terminal plating of electronic components, fine pitch connectors, and flexible printed circuits (FPCs) are invariably hampered by the serious problem of tin whisker formation. Here, a new and simple method, the JVC Micro Island (JMI) process, is proposed for the prevention of tin whisker formation in fine pitch connectors. Briefly, the base copper terminal was acid etched to afford a roughened surface, which was then tin plated. The contact test with Knoop indentation proved the effectiveness of the present process. The maximum length of the as-formed tin whiskers was less than 50 μm. The solderability of the JMI FPCs was not influenced by the present process. Thus, the new JMI process is shown to have a great advantage for the prevention of tin whisker formation in fine pitch connectors.     

Dependence of Output Power on Cavity Length in a Gyrotron Backward Wave Oscillator

A relativistic electron beam (500 keV, 200 A, 10 ns) generated magnetically tunable microwave radiation in a frequency range of 9-13 GHz when it is injected into an X-band rectangular waveguide immersed in a uniform axial magnetic field (4-10 kG). The mechanism of the microwave radiation was identified as the gyrotron backward wave interaction. The output power of the radiated microwave increased exponentially with the increase of the cavity length.     

A new remote control room for tokamak operations

This paper presents a summary of a new remote tokamak control room constructed near the offices of DIII-D's scientific staff. This integrated system combines hardware, software, data, and control of the room (R-232) into a unified package that has been designed and constructed in a generic fashion so that it can be used with any tokamak operating worldwide. The room is approximately 300 ft² and can accommodate up to 12 seated participants. Mounted on the wall facing each scientist are five 52″ LCD televisions and mounted to the wall on their right are six 24″ LCD monitors. Each seat has associated with it a 24″ monitor, network connection, and power and the scientist is either provided with a computer or they can use their own. The room has been used for operation of DIII-D, EAST, and KSTAR. Due to the long distances, data from EAST and KSTAR was brought back to local DIII-D computers in one large parallel network transfer and subsequently served to scientists in the remote control room to other US collaborators. This parallel data transfer allowed the data to be available to US participants between pulses making remote experimental participation highly effective.     

Sonication‐Induced Formation of Size‐Controlled Self‐Assemblies of Amphiphilic Janus‐Type Polymers as Optical Tumor‐Imaging Agents

In this study, amphiphilic Janus‐type polymers were synthesized via ring‐opening metathesis polymerization (ROMP), multiple vicinal diol formation, and grafting of poly(ethylene glycol) monomethyl ether (mPEG). These amphiphilic polymers formed self‐assemblies, which were a mixture of micelles and multimicellar aggregates, in water. By choosing suitable Janus‐type polymers and irradiating an aqueous solution of polymers using a sonicator, either small micelles or large multimicellar aggregates were obtained selectively. Hydrophobic substituents controlled the aggregation–disaggregation behavior, leading to the formation of metastable self‐assemblies by sonication. The formation of self‐assemblies with a uniform size was affected by ultrasonic frequency, rather than power. In vivo optical tumor imaging revealed that the large‐size multimicellar aggregates persisting for a long time in blood circulation slowly accumulated in tumor tissues. In contrast, the tumor site was rapidly, clearly visualized using the small‐size micelles.     

A high-speed-retry banyan switch architecture for giga-bit-rate BISDN networks

This paper proposes a high-speed ATM switch architecture for handling cell rates of several Gb/s in a broadband communication switching system or cross-connect system. The proposed switch architecture, named the high-speed-retry banyan switch, employs a bufferless banyan network between input and output buffers; a cell is repeatedly transmitted from an input buffer until it can be successfully transmitted to the desired output buffer. A simple cell-retransmission algorithm, is employed as is a ring-arbitration algorithm for cell conflict. They are suitable for FIFO type buffers and bufferless highspeed devices. Good traffic characteristics which are independent of switch size are achieved for an internal speed ratio of only four times the input line speed. A prototype system with the internal speed of 1·2 Gb/s is constructed in order to confirm the basic operation of the high-speed-retry banyan switch. The prototype system, even in its present state, could be used to realize a giga-bit-rate BISDN switching system.     

Low temperature specific heat of intercalation compounds M x TiS2 (M = 3d transition metals)

Specific heats of intercalation compounds Fe_x TiS₂ (x = 0–1/3) and M_1/4 TiS₂ (M = Mn, Fe, Co and Ni) have been measured in the temperature range 0.35–5 K using an ac calorimetry method. The temperature dependence of the specific heats for these materials is written as the sum of electronic, lattice and anomalous terms. The anomalous specific heats show a Schottky type behavior, which is due to a very small amount of localized 3d atoms with crystal-field splittings, but the remaining majority of the intercalated guest 3d atoms are regarded as having itinerant electron character that contributes to the enhancement of the density of states at the Fermi energy or of electronic specific heat coefficient.     

Inspection policy for two-unit parallel redundant system

This paper deals with a single-server two-unit parallel redundant system with non-negligible inspection time. We shall assume that a failure of a unit or the system failure is detected by inspection only. We consider two inspection policies and under each inspection policy the stationary availability is derived by applying Piecewise Markov Process. Optimum inspection schedule is discussed to maximize the stationary availability of the system. A numerical example is presented.