scholarly journals Heating-free, room-temperature operation of a radiofrequency-to-light signal transducer with a membrane oscillator and a built-in metasurface mirror

2021 ◽  
Author(s):  
Yusuke Tominaga ◽  
Atsushi Mikami ◽  
Akiya Iwamura ◽  
Koji Usami ◽  
Kazuyuki Takeda
Keyword(s):  
Laser Heating ◽  
Room Temperature ◽  
Light Signal ◽  
Stable Operation ◽  
Aluminum Electrode ◽  
Signal Transducer ◽  
Optical Signals ◽  
Characteristic Oscillation ◽  
A Chain ◽  
Membrane Oscillator

Abstract We present an electro-mechano-optical radiofrequency (rf)-to-light signal transducer robust against laser heating and thus operational at room temperature. A metal-free, low-loss metasurface mirror and an aluminum electrode made separately on a Si3N4 membrane oscillator comprise a chain of electro-mechanical and opto-mechanical systems, mediating electrical and optical signals through the (2,2)-mode characteristic oscillation. We demonstrate up-conversion of rf signals at 175.2 MHz by 6 orders of magnitude in frequency to an optical regime with the transfer efficiency of 2.3×10-9, also showing stable operation due to reduced laser heating of the mirror.

Reactions of Thiyl Radicals. XI. Further Investigations of Thiol–Disulfide Photolyses in the Liquid Phase

1973 ◽  
Vol 51 (9) ◽  
pp. 1410-1415 ◽  
Author(s):  
Donna D. Carlson ◽  
Arthur R. Knight
Keyword(s):  
Liquid Phase ◽  
Room Temperature ◽  
Liquid Mixtures ◽  
Quantum Yields ◽  
Chain Reaction ◽  
Photochemical Process ◽  
High Quantum Efficiency ◽  
Thiyl Radicals ◽  
Exchange Processes ◽  
A Chain

The photolysis of C2H5SH liquid at 2537 Å has been shown to give H2 and C2H5SSC2H5 at equal rates with a quantum yield of 0.25. The photolysis of ethanethiol – methyl disulfide liquid mixtures leads, via a chain reaction involving propagation by attack of thiyl radicals on the disulfide S—S bond, to the formation with high quantum efficiency of CH3SH, C2H5SSC2H5 and, as an intermediate that is consumed after long exposures, CH3SSC2H5. The net result of the sequence of exchange processes is the essentially irreversible conversion of the methyl disulfide into methanethiol. The same overall reaction occurs thermally at room temperature, but the rate is appreciably less than that of the photochemical process. The quantum yields of formation of the unsymmetrical disulfides arising from the photochemically initiated exchange reaction in equimolar mixtures of CH3SSCH3 + n-C3H7SSC3H7 and C2H5SSC2H5 + n-C3H7SSC3H7 have been shown to be 6.9 and 4.4, compared to 355 for CH3-SSCH3 + C2H5SSC2H5 mixtures. In all three types of system examined in this investigation all thiyl radicals can be accounted for stoichiometrically on the basis of exchange and combination reactions alone, indicating negligible disproportionation of these species in condensed phase.

Structure and water durability of tin(II) organosilicophosphate glasses prepared by nonaqueous acid–base reactions

2006 ◽  
Vol 21 (7) ◽  
pp. 1798-1806 ◽  
Author(s):  
Megumi Mizuno ◽  
Masahide Takahashi ◽  
Toshinobu Yoko
Keyword(s):  
Room Temperature ◽  
Orthophosphoric Acid ◽  
Chain Structure ◽  
Acid Base ◽  
Humid Atmosphere ◽  
Water Durability ◽  
Magnetic Resonance Technique ◽  
A Chain ◽  
Degree Of Condensation ◽  
High Degree

Tin(II) organosilicophosphate glasses were prepared by nonaqueous acid–base reactions using orthophosphoric acid, dimethyldichlorosilane, and tin(II)chloride as the starting materials. The structure of the methylsiloxane-phosphate copolymer (methylsilicophosphate) and tin(II) methylsilicophosphate glasses was mainly investigated by the 31P nuclear magnetic resonance technique. A chain structure composed of the –(P–O–Si–O)m– silicophosphate bonds was found as the main structural unit in the methylsilicophosphate prepared by mixing orthophosphoric acid and dimethyldichlorosilane at room temperature. Tin(II) methylsilicophosphate glasses could be prepared by introducing SnCl2 as a cross-linking agent of silicophosphate chains. By increasing the reaction temperature, it was possible to promote the reaction and then to increase the network dimensions of the resultant tin(II) methylsilicophosphate glasses. It was found that the glasses with a high degree of condensation tend to have a better water durability in a humid atmosphere.

Die Reaktion des weißen Phosphors mit Tetrachlorkohlenstoff unter dem Einfluß von Y-Strahlung, Licht und Wärme

1962 ◽  
Vol 17 (11) ◽  
pp. 703-711 ◽  
Author(s):  
D. Perner ◽  
A. Henglein
Keyword(s):  
Activation Energy ◽  
Carbon Tetrachloride ◽  
Room Temperature ◽  
Main Product ◽  
Thermal Reaction ◽  
White Phosphorus ◽  
Low Molecular Weight ◽  
Red Phosphorus ◽  
Γ Radiation ◽  
A Chain

Red phosphorus, phosphorus trichloride, trichloromethylphosphorus dichloride, hexachloroethane and a polymer consisting of carbon and chlorine are formed when solutions of white phosphorus in carbon tetrachloride are exposed to γ-radiation. Red phosphorus is the main product at room temperature. However, its yield rapidly decreases at higher temperatures and the yields of the low molecular weight products strongly increases. Typical G-values:The formation of the products PCl3 and CCl3PCl2 occurs by a chain reaction between phosphorus and carbon tetrachloride. A mechanism is proposed in which free radicals from the radiolysis of carbon tetrachloride attach the dissolved white phosphorus. The propagation of the chain is caused by chlorine transfer from carbon tetrachloride to partly trichloroalkylated or chlorinated phosphorus chains or rings. The activation energy of this transfer is found to be equal to 8.2 kcal/mole. This reaction with carbon tetrachloride is favored at high temperature while the competing process of the combination of those intermediate phosphorus chains and rings to give red phosphorus prodominates at low temperature. The red phosphorus formed contains one CCl3 group per 7 atoms of phosphorus. It was possible to synthesize trichloromethylphosphorus dichloride, trichloromethylphosphorus tetrachloride and trichloromethylphosphorus dibromide by treating the red phosphorus with chlorine or bromine, respectively.The thermal reaction between phosphorus and carbon tetrachloride also leads to PCl3 and CCl3PCl2 (ratio 1:3). Small amounts of red phosphorus and C2Cl6 could be traced too. The activation energy of the thermal reaction amounts to 22.2 kcal/moles. The photo reaction (visible light) leads to the same products. However, red phosphorus still is the main product at 100°C.

scholarly journals High-Pressure Structural Behavior and Equation of State of Kagome Staircase Compound, Ni3V2O8

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 910
Author(s):  
Daniel Diaz-Anichtchenko ◽  
Robin Turnbull ◽  
Enrico Bandiello ◽  
Simone Anzellini ◽  
Daniel Errandonea
Keyword(s):  
High Pressure ◽  
Equation Of State ◽  
Density Functional ◽  
Room Temperature ◽  
Ambient Pressure ◽  
Density Functional Theory Calculations ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
A Chain

We report on high-pressure synchrotron X-ray diffraction measurements on Ni3V2O8 at room-temperature up to 23 GPa. According to this study, the ambient-pressure orthorhombic structure remains stable up to the highest pressure reached in the experiments. We have also obtained the pressure dependence of the unit-cell parameters, which reveals an anisotropic compression behavior. In addition, a room-temperature pressure–volume third-order Birch–Murnaghan equation of state has been obtained with parameters: V0 = 555.7(2) Å3, K0 = 139(3) GPa, and K0′ = 4.4(3). According to this result, Ni3V2O8 is the least compressible kagome-type vanadate. The changes of the crystal structure under compression have been related to the presence of a chain of edge-sharing NiO6 octahedral units forming kagome staircases interconnected by VO4 rigid tetrahedral units. The reported results are discussed in comparison with high-pressure X-ray diffraction results from isostructural Zn3V2O8 and density-functional theory calculations on several isostructural vanadates.

Start-up and Steady Operation of Shortcut Nitrification System to Treat Wastewater

2012 ◽  
Vol 610-613 ◽  
pp. 1760-1763
Author(s):  
Li Xu ◽  
Xue Wu ◽  
Ming Fen Niu ◽  
Si Li ◽  
Hong Jing Jiao ◽  
...  
Keyword(s):  
Short Range ◽  
Room Temperature ◽  
Ammonia Concentration ◽  
Experimental Temperature ◽  
Nitrifying Bacteria ◽  
Stable Operation ◽  
High Concentration ◽  
Nitrogen And Phosphorus ◽  
Start Up ◽  
The Stability

The purpose of this paper is to obtain a start-up of short-cut nitrification systems to treat wastewater with high concentration of nitrogen and phosphorus under laboratory conditions. By starting the nitrification system at room temperature we can achieve the effective accumulation of nitrifying bacteria. Then by increasing experimental temperature and pH, and increasing the concentration of nitrogen and phosphorus in influent, to inhibit the growth of NOB in the systems and promote the accumulation of AOB. So we can make the effluent have a higher concentration of NO2--N. In the stable operation stage we can constantly improve ammonia concentration in the influent, to observe the stability of the each indicators of effluent. This experiment showed that the wastewater with high concentration of nitrogen and phosphorus can better promote the accumulation of AOB, to achieve the effect of short-range nitrification.

Nano-Scale Silicon Quantum Dot-Based Single-Electron Transistors and Their Application to Design of Analog-to-Digital Convertors at Room Temperature

2017 ◽  
Vol 26 (12) ◽  
pp. 1750201
Author(s):  
Hamed Aminzadeh ◽  
Mohammad Ali Dashti ◽  
Mohammad Miralaei
Keyword(s):  
Quantum Dot ◽  
Coulomb Blockade ◽  
Room Temperature ◽  
Symmetric Functions ◽  
Single Electron ◽  
Stable Operation ◽  
Single Electron Transistors ◽  
Analog To Digital ◽  
Temperature Range ◽  
Electron Transistors

Room-temperature analog-to-digital converters (ADCs) based on nanoscale silicon (Si) quantum dot (QD)-based single-electron transistors (SETs) can be very attractive for high-speed processors embedded in future generation nanosystems. This paper focuses on the design and modeling of advanced single-electron converters suited for operation at room temperature. In contrast to conventional SETs with metallic QD, the use of sub-10-nm Si QD results in stable operation at room temperature, as the observable Coulomb blockade regime covers effectively the higher temperature range. Si QD-based SETs are also fully compatible with advanced CMOS technology and they can be manufactured using routine nanofabrication steps. At first, we present the principles of operation of Si SETs used for room-temperature operation. Possible flash-type ADC architectures are then investigated and the design considerations of possible Coulomb oscillation regimes are addressed. A modified design procedure is then introduced for [Formula: see text]-bit SET-based ADCs, and validated through simulation of a 3-bit ADC with a sampling frequency of 5 GS/s. The ADC core is comprised from a capacitive signal divider followed by three periodic symmetric functions (PSFs). Simulation results demonstrate the stability of output signals at the room-temperature range.

Structural and Thermal Properties of Cu Doped Nanocrystalline Tin Selenide

2013 ◽  
Vol 665 ◽  
pp. 15-21
Author(s):  
N.N. Gosai ◽  
G.K. Solanki ◽  
K.D. Patel ◽  
Keyur S. Hingarajiya
Keyword(s):  
Activation Energy ◽  
Kinetic Parameters ◽  
Room Temperature ◽  
Thermal Characteristics ◽  
Stable Operation ◽  
X Rays ◽  
Size Estimation ◽  
Prepared Compound ◽  
Thermoanalytical Techniques ◽  
Tin Selenide

Nanocrystalline Copper doped Tin Selenide have been prepared by aqueous solution method in double distilled water at room temperature. All the chemicals used for this were of Analytical Reagent grade and of 99.999 % purity. Structural confirmation of prepared compound and particle size estimation was done from X-ray diffractogram obtained by CuKαradiation of wavelength 1.540 nm. Compositional or elemental analysis of this compound was done using energy dispersive analysis of X-rays (EDAX) and it is found that prepared compound is nearly stoichiometric in nature. Thermal characteristics of SnSeCu nanocrystals were studied employing thermoanalytical techniques, viz. TGA and DTA. Thermogravimetric analysis (TGA) has been used for many years to evaluate thermal stability of material as it will determine the range of stable operation for a device made up out of these materials under investigation. Thermal analysis experiments were carried out with constant heating rate of 10 °C/ min in air from room temperature to 900 °C. The DTA pattern of SnSeCu nanocrystal shows a strong endothermic peak at 450 °C. The objective of this study is to determine activation energy and other kinetic parameters of prepared compound. Broido and Coats-Redfern (C-R) models are used to evaluate different kinetic parameters viz. activation energy, entropy, enthalpy, Gibbs mean free energy and they were found to have good correlation coefficient.

A Fiber-Optic Tip-Shroud Deflection Measurement System

2000 ◽  
Vol 123 (2) ◽  
pp. 359-362 ◽  
Author(s):  
R. A. Rooth ◽  
W. Hiemstra
Keyword(s):  
Gas Turbine ◽  
Fiber Optic ◽  
Turbine Blades ◽  
Stable Operation ◽  
Distance Information ◽  
Optical Signals ◽  
Good Spatial Resolution ◽  
Characteristic Features ◽  
The Individual ◽  
Tip Shroud

A Dutch utility faced the fact that a second stage set of turbine blades of a gas turbine had to be replaced long before the estimated lifetime as a result of tip shroud deflection. This deflection caused the risk of loss of support between the individual tip shroud segments. The goal of this paper is to find the cause of the problem, to see how it increases with time, and to take appropriate action to prevent the problem from occurring again. A fiber-optic tip-shroud deflection monitor has been developed and tested on a gas turbine to study this phenomenon in real time. The optical system is based on astigmatism to derive distance information from the measured optical signals. Characteristic features from the system are the good spatial resolution of about 1 mm, the distance resolution of about 0.1 mm and the distance from the probe tip to the target of about 20 mm. These specifications are difficult to achieve with, for example, capacitive sensors. The probe tip can with stand temperatures of about 500°C. The system can be calibrated in situ, given a stable operation of the gas turbine. This is accomplished by stepping the probe tip over some distance and recording the signals corresponding to a certain point on the tip shroud. The instrument has been used to monitor the tip-shroud deflection in a gas turbine at various loads and over a time span of several months. The results indicate that the deflection can be divided in a part depending on the load and a part that is a permanent deflection. Based on the results, it can be judged whether blades need to be rejected because of a too large deflection.

The Quantum Yield of Oxidation of Hevea Rubber and GR-S

1948 ◽  
Vol 21 (3) ◽  
pp. 639-653 ◽  
Author(s):  
E. J. Hart ◽  
M. S. Matheson
Keyword(s):  
Quantum Yield ◽  
Room Temperature ◽  
Wave Length ◽  
Radical Reaction ◽  
Quantum Yields ◽  
Initial Reaction ◽  
Free Radical Reaction ◽  
Stable Intermediate ◽  
A Chain ◽  
Reaction Chain

Abstract The initial quantum yields of photoöxidation for purified Hevea rubber have been measured for various mercury arc lines in the wave length region 2537– 17,400 A˚. All experiments were carried out at room temperature and at an oxygen pressure of one atmosphere. At the outset of irradiation all quantum yields of combined oxygen are less than unity, although the quantum efficiency rises above 1.0 at 2537 and 3130 A˚. as photoöxidation proceeds. The low quantum yield suggests that in its initial stages (less than 0.1 per cent oxygen combined on the rubber) photoöxidation is not a chain reaction. It is postulated as the first step in rubber photoöxidation that the light activated rubber group reacts with oxygen to give a relatively stable intermediate which does not immediately dissociate to give a free radical reaction chain. The quantum yields of photoöxidation of purified GR-S were also measured under the same conditions as used for rubber. At each wave length the quantum yield was lower than for rubber, indicating formation of a stable intermediate in the initial reaction also.

Synthesis, Crystal Structure and Spectroscopic Studies of New Charge Transfer Compounds Obtained by Reaction of TTF and the Polyoxoanion [Mo6O19]2−

1989 ◽  
Vol 173 ◽  
Author(s):  
C. Bellitto ◽  
D. Attanasio ◽  
M. Bonamico ◽  
V. Fares ◽  
P. Imperatori ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electrical Conductivity ◽  
Charge Transfer ◽  
Room Temperature ◽  
Mixed Valence ◽  
Spectroscopic Studies ◽  
Chemical Formula ◽  
Xps Spectra ◽  
Radical Cation Salts ◽  
A Chain

ABSTRACTTwo different tetrathiafulvalene radical cation salts of the [M06O19]2−polyoxoanion have been isolated and characterized. Compound 1 corresponds to the chemical formula (TTF)3[Mo6019]. The crystal structure shows a ID stack of the donor TTF molecule, and each stack fits into channels formed by the anions. Within the stack a chain of trimers is identified, the inter-trimeric distance being 3.51 Å. The I.R., electronic and XPS spectra suggest the compound to be a mixed-valence salt. The electrical conductivity at room temperature is σ = 10−4Ω−1cm−1Compound 2 corresponds to the chemical+formula (TTF)2[M06019] . The compound consists of isolated (TTF+•)2dimers, interspersed with the polyoxoanions. In agreement with this crystal structure the compound is a diamagnetic insulator.

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