Growth of MnSi1.7 Layers on MnSi Substrate by Molten Salt Method

MnSi_1.7 layers have been successfully grown using a molten salt method. It was found that homogeneous MnSi_1.7 layers with columnar domain structure can be grown on MnSi substrates. The dependence of the thickness and domain structure of the layers on the growth conditions was investigated. It was found that the deposited atoms, namely Si, were the dominant diffusion species, and the formation of Kirkendall voids was avoided for the silicidation reaction based on interdiffusion. The layer thickness could be controlled by the growth temperature and time, and was diffusion controlled. The interdiffusion coefficient was approximately 5 × 10^?10 cm²/s for growth temperature of 900°C. The activation energy of interdiffusion was deduced to be approximately 1.1 eV for growth of the MnSi_1.7 layers. This growth technique provides a simple and controllable method to grow large-area, high-quality MnSi_1.7 layers.     

Observation of Amplified Stimulated Terahertz Emission from Optically Pumped Heteroepitaxial Graphene-on-Silicon Materials

We experimentally observed the fast relaxation and relatively slow recombination dynamics of photogenerated electrons/holes in a heteroepitaxial graphene-on-Si material under pumping with a 1550-nm, 80-fs pulsed fiber laser and probing with the corresponding terahertz beam generated by and synchronized with the pumping laser. The time-resolved electric-nearfield intensity originating from the coherent terahertz photon emission is electrooptically sampled in total-reflection geometry. The Fourier spectrum fairly agrees the product of the negative dynamic conductivity and the expected THz photon spectrum reflecting the pumping photon spectrum. This phenomenon is interpreted as an amplified stimulated terahertz emission.     

A 4 V Operation,Flexible Braille Display Using Organic Transistors,Carbon Nanotube Actuators,and Organic Static Random‐Access Memory

A sheet‐type Braille display operating at 4 V has been successfully fabricated by integrating organic an static random‐access memory (SRAM) array with carbon nanotube (CNT)‐based actuators that are driven by organic thin‐film transistors (control‐TFTs). The on current of organic control‐TFTs that drive CNT actuators exceeds 3 mA, the mobility exceeds 1 cm² V^?1s^?1, and the on/off ratio exceeds 10⁵ at an operational voltage of 3 V. By adjusting the process time for the formation of the aluminum oxide dielectrics, the threshold voltage of the organic TFTs can be systematically controlled. This technique leads to an improved static noise margin of the SRAM and enables its stable operation with a short programming time of 2 ms at a programming voltage of 2 V. As a demonstration of the operation of one actuator with one control‐TFT and SRAM: the displacement of actuator exceeds 300 μm at an operation voltage of 4 V, which is large enough for a blind person to recognize the pop‐up of braille dots. Integrating the SRAM array reduces the frame rate of a 12 dot × 12 dot display from 1/21.6 s to 1/2.9 s.     

Bubble formation in cocurrently upward flowing liquid

The effects of liquid velocity, nozzle diameter, gas chamber volume and gas flow rate on volumes, shapes and growth curves of bubbles formed at a nozzle submerged in a cocurrently upward flowing liquid in a bubble column were experimentally investigated. The bubble volume decreases with increasing liquid flow velocity. The effect of liquid flow velocity on the volume of bubble increases with an increase in the gas flow rate. To simulate bubble formation at a nozzle submerged in cocurrently upward flowing liquid, a revised non-spherical bubble formation model was proposed. Bubble volumes, bubble growth curves and shapes experimentally obtained in this study, as well as in previous experimental studies, are well predicted by the present model.     

Radiation characteristics as a function of the gas flow rate emitted from argon torch plasma arc discharge

When a reduction of the waste and dissolution of the iron are carried out by means of an arc plasma, the radiant power of the arc should be suppressed. In those cases the radiant power from the plasmas has to be precisely controlled. Therefore, we tried to measure the radian power from the torch plasma using a power meter. The radiant power was measured to be about 620 to 950 W for an external plasma length of 2 cm at a current of 100 A, with gas flow rates of 4 to 20 l/min (Normal), and increases in proportion to the 0.25 to 0.37 power of the gas flow rate and with the increment of external plasma length and the plasma current. The total radiant efficiency is 32 to 40% in the condition mentioned above in the sphere model. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 139(3): 1–8, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10006     

Catalytic properties of metallosilicates containing iron group metals in light-olefin conversions

Metallosilicate catalysts containing iron-group metals were prepared by using the rapid crystallization method. These catalysts had the pentasil structure similar to ZSM-5 zeolite. In case of less metal content, the iron-group metal was incorporated into silicate crystal, and contributed to the formation of strong acid sites. The difference in results of light olefin conversion was understood as reflecting the properties of strong acid sites on each metallosilicate.     

Azamacrocyclic metal complexes as CXCR4 antagonists

The chemokine receptor CXCR4 is a member of the seven transmembrane GPCR family, which is implicated in multiple diseases, including HIV infection, cancers, and rheumatoid arthritis. Low-molecular-weight nonpeptidic compounds, including AMD3100 and various pyridyl macrocyclic zinc(II) complexes, have been identified as selective antagonists of CXCR4. In the present study, structure-activity relationship studies were performed by combining the common structural features of alkylamino and pyridiyl macrocyclic antagonists. Several new zinc(II) or copper(II) complexes demonstrated potent anti-HIV activity, strong CXCR4-binding activity, and significant inhibitory activity against Ca(2+) mobilization induced by CXCL12 stimulation. These results may prove useful in the design of novel CXCR4 antagonists, and the compounds described could potentially be developed as therapeutics against CXCR4-relevant diseases or chemical probes to study the biological activity of CXCR4.