Cathode Research Articles

A Rugged Cathode for Photoelectron and DC Thermionic Operation

A Rugged Cathode for Photoelectron and DC Thermionic Operation

The impact of energy and delay angle of injected carriers on energy conversion efficiency in a Gunn diode with an intricate cathode

The paper is devoted to numerical investigation of the influence of the energy and delay angle of injected carriers on the energy conversion efficiency at the fundamental mode in an n -GaAs Gunn diode with an intricate cathode. An increase in the energy of the carriers injected into the diode’s active region (for the delay angles within a range corresponding to positive values of the diode efficiency) is shown to lead to a shift of this range towards larger angles of lag. A new structure of the Gunn diode is suggested, which involves special cathode contacts consisting of alternating quasiisland ohmic contacts and control electrode domains.

Irradiation of intense characteristic x-rays from weakly ionized linear molybdenum plasma.

In the plasma flash x-ray generator, a high-voltage main condenser of approximately 200 nF is charged up to 55 kV by a power supply, and electric charges in the condenser are discharged to an x-ray tube after triggering the cathode electrode. The flash x-rays are then produced. The x-ray tube is a demountable triode that is connected to a turbo molecular pump with a pressure of approximately 1 mPa. As electron flows from the cathode electrode are roughly converged to a rod molybdenum target of 2.0 mm in diameter by the electric field in the x-ray tube, weakly ionized linear plasma, which consists of molybdenum ions and electrons, forms by target evaporation. At a charging voltage of 55 kV, the maximum tube voltage was almost equal to the charging voltage of the main condenser, and the peak current was about 20 kA. When the charging voltage was increased, the linear plasma formed, and the K-series characteristic x-ray intensities increased. The K lines were quite sharp and intense, and hardly any bremsstrahlung rays were detected. The x-ray pulse widths were approximately 700 ns, and the time-integrated x-ray intensity had a value of approximately 35 micro C/kg at 1.0 m from the x-ray source with a charging voltage of 50 kV.

A novel Approach towards the Synthesis of LiMV04 (M = Ni, Mn) Cathodes

A novel Approach towards the Synthesis of LiMV04 (M = Ni, Mn) Cathodes

Degradation of Methyl Orange via lndirect Anodic Oxidation in an Undivided Cell

The degradation of methyl orange (MO) was explored in the presence of redox mediator via electrochemical reaction in an undivided cell. The results revealed that the color of the solution changed from orange to colorless during electrolysis.The main factors affecting the degradation rate of methyl orange were the concentration of methyl orange, the current density, and the kind of electrolyte, the pH, and the electrode materials. A minor factor was the concentration of NaBr. In this system,the maximum value of the degradation rate of MO was 30 mg coul-1 under optimum operating conditions, i.e., the best operating conditions were 20 ppm methyl orange, 1.25 mA cm-2, 0,025 M NaBr, and pH 6.8, using graphite as the anode and cathode.

Emission characteristics of semiconductor cathodes

AbstractThis paper describes emission characteristics of MOS (metal–oxide–semiconductor) electron tunneling cathodes and Si field emitters, and shows that their characteristics reflect the energy band structures of the semiconductor and the electron transport in an incorporated semiconductor device. In addition, it proposes hybrid electronics combining solid‐state device and vacuum device technologies, and shows that this approach provides highly efficient high‐frequency devices with coverage from the microwave to the optical wave regions. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 84(5): 1–9, 2001

Electrochemical Characteristics of Anode-supported Solid Oxide Fuel Cells

YSZ ( yttria-stabilized zirconia)-modified LSM composite cathodes were fabricated by formation of YSZ film on triple phase boundary (TPB) of LSM/YSZ/gas. The YSZ coating film greatly enlarged electrochemical reaction sites from the increase of additional TPB. The composite cathode was formed on thin YSZ electrolyte (about 30 Um thickness) supported on an anode and then I-V characterization and AC impedance analyses were performed at temperature between . As results of the impedance analysis on the cell at with humidified hydrogen as the fuel and air as the oxidant, R1 around the frequency of 1000 Hz represents the anode Polarization. R2 around the frequency of 100Hz indicates the cathode polarization, and R3 below the frequency of 10 Hz is the resistance of gas phase diffusion through the anode. The cell with the composite cathode produced power density of at air and oxygen atmosphere, respectively. The I-V curve could be divided into two parts showing distinctive behavior. At low current density region (part I) the performance decreased steeply and at high current density region (part II) the performance decreased gradually. At the part I the performance decrease was especially resulted from the large cathode polarization, while at the part H the performance decrease related to the electrolyte polarization.

Electrodeposition of Copper on Porous Reticular Cathode (II) - Effect of PEG and MPS on throwing Power-

The effect of organic additives such as PEG ind MPS on throwing power have been studied in the fabrication of porous reticular metal by electrodeposition using the mixture of cupric sulfate and sulfuric acid as electrolyte. Both the polarization test and the electrodeposition on the stacked electrodes, mean pore diameter of which was , were performed to illustrate the behavior of throwing power quantitatively. As far as PEG was concerned, it lowered throwing power of electrodeposition on the porous electrode used in this work while the addition of MPS up to 500 ppm in electrolyte enhanced throwing power monotonously. When both MPS and PEG were added in electrolyte, the effect of MPS on throwing power was superior to that of PEG. However, the excess addition of MPS was found to cause the defect in mechanical strength of deposit layer. From the result of SEM observation, it could be concluded that less than 50 ppm of MPS in electrolyte was appropriate to avoid the breakage of deposit layer.

The Relation between the Phase-Shift Profile for the Intermediate Frequencies and the Langmuir Adsorption Isotherm

The relation between the phase-shift profile for the intermediate frequencies and the Langmuir adsorption isotherm at the poly- aqueous electrolyte interface has been studied using ac impedance measurements, i.e., the phase-shift methods. The suggested interfacial equivalent circuit consists of the serial connection of the electrolyte resistance (), the faradaic resistance and the equivalent circuit element of the adsorption pseudocapacitance . The delayed phase shift depends on both the cathode potential (E) and frequency (f), and is given by . The phase-shift profile for the intermediate frequency (ca. 6Hz) can be used as an experimental method to determine the Langmuir adsorption isotherm (9 vs. E). The equilibrium constant (K) for H adsorption and the standard free energy of H adsorption at the poly- electrolyte interface are , respectively. The H adsorption is attributed to the over-potentially deposited hydrogen (OPD H).

Fabrication and Electrochemical Characterization of All Solid-State Thin Film Micro-Battery by in-situ Sputtering

All solid-state thin film micro-batteries consisting of lithium metal anode, an amorphous LiPON electrolyte and cathode of vanadium oxide have been fabricated and characterized, which were fabricated with cell structure of . The effect of various oxygen partial pressure on the electrochemical properties of vanadium oxide thin films formed by d.c. reactive sputtering deposition were investigated. The vanadium oxide thin film with deposition condition of ratio showed good cycling behavior. In in-siか process, the LiPON electrolyte was deposited on the films without breaking vacuum by r.f. magnetron sputtering at room temperature. After deposition of the amorphous LiPON, the Li metal films were grown by a thermal evaporator in a dry room. The charge-discharge cycle measurements as a function of current density and voltage variation revealed that the thin film had excellent rechargeable properly when current density was . and cut-off voltage was between 3.6 and 2.7V In practical experiment, a stopwatch ran on this thin film micro-battery. This result means that thin film micro-battery fabricated by in-siか process is a promising for power source for electronic devices.

Effect of Cathode/anode Weight Ratio in $LiCoO_2/MPCF$ Cell

Li-ion cells employ lithium transtion metal oxide as the cathode material and carbon as anode material. To manufacture Li-ion cell with higher capacity and better cycle life, the utilization of electrode materials should be as high as possible without lithium deposition onto the carbon surface during charging. A careful design of cell balance between cathode and anode materials as well as a proper charge method is a key factor to design Li-ion cell with long cycle life. In this study, we investigated the effect of cathode/anode weight ratio on the performance of cell. First we evaluated the charge-discharge behaviours of half-cells. And cylindrical Li-ion cells were fabricated using graphitized MPCF anode and cathode. The voltage profiles for each half-cell in cell were measured by using lithium metal as a reference electrode. Also, we evaluated the cyclic performance of cells according to weight ratio. From the result of experiment cathode utilization was independent of weight ratio, but MPCF anode utilization was dependant on weight ratio. Also, the optimal weight ratio of cell was found to be .

Synthesis of Azobenzene Derivatives via Controlled Potential Cathodic Electrolysis

Using an H-type divided cell, reductive coupling reaction of nitroarene toward azobenzenes in a mild condition was successfully accomplished by the controlled potential cathodic electrolysis reaction. Optimum reaction potential of each reaction was determined based on cyclic voltammetric behavior in methanol solution at Pb or Pt cathode, and Pt anode. In most cases, reductive coupling reactions were successful with excellent yields regardless of the position and the character of the substituents.

Charge/discharge characteristics of $LiCoO_2$ thin film prepared by electron-beam evaporation with deposition rate and annealing temperatures

Lithium cobalt oxide cathode for thin-film rechargeable lithium batteries were fablicated by electron-beam evaporation. Annealed lithium cobalt oxide, which was deposited on to stainless steel substrate, showed well-developed (003) planes of the hexagonal structure and potential plateau at . Lithium cobalt oxide thin films had the stoichiometric Li/co ratio at high deposition rates and exhibited high discharge capacity at . As the annealing temperature increased, discharge capacity increased with maximum value at , but showed low capacity as a result of reaction with substrate above . Unuiformity of the lithium and cobalt in the depth profile gave initial capacity loss with charge/discharge performance.

Charge-discharge behaviour of lithium ion secondary battery using graphitized mesophase pitch-based carbon fiber anodes

Mesophase pitch-based carbon fibers(MPCF) have been investigated as an anode active material for lithium ion secondary battery. Graphitized MPCF gives high discharge capacity and good Ah efficiency. MPCF/Li cell shows an initial discharge capacity of 300 mAh/g and Ah efficiency above at a current density of 25 mA/g at V. Cylindrical lithium ion secondary battery was fabricated using mixed carbon anode and , cathode. In order to improve the cyclability of lithiun ion secondary battery, other carbons were added to the MPCF up to . The cycle performance of lithium ion secondary battery using mixed carbons was superior to those using graphitized MPCF.

Anode to cathode distance

Anode to cathode distance

Anode to cathode distance

Anode to cathode distance

Anode to cathode distance

Anode to cathode distance

Anode to cathode distance

Anode to cathode distance

From printed page to cathode tube: The evolution of the laboratory primate newsletter

From printed page to cathode tube: The evolution of the laboratory primate newsletter

From printed page to cathode tube: The evolution of the laboratory primate newsletter

From printed page to cathode tube: The evolution of the laboratory primate newsletter