Pumping conditions and cross-section laser power distribution in low-pressure nitrogen laser

2018 ◽  
Keyword(s):  
Cross Section ◽  
Power Distribution ◽  
Laser Power ◽  
Low Pressure ◽  
Nitrogen Laser

Effects of Electrical Discharges in Low Pressure Gases on the Morphology of Polyethylene Crystals

1974 ◽  
Vol 32 ◽  
pp. 544-545
Author(s):  
L.H. Bolz ◽  
D.H. Reneker
Keyword(s):  
Power Distribution ◽  
Electrical Discharge ◽  
Dielectric Breakdown ◽  
Ionic Species ◽  
Low Pressure ◽  
Polymer Surfaces ◽  
Electrical Discharges ◽  
Adhesive Bonds ◽  
Power Distribution Lines ◽  
Modification Of The Surface

The attack, on the surface of a polymer, by the atomic, molecular and ionic species that are created in a low pressure electrical discharge in a gas is interesting because: 1) significant interior morphological features may be revealed, 2) dielectric breakdown of polymeric insulation on high voltage power distribution lines involves the attack on the polymer of such species created in a corona discharge, 3) adhesive bonds formed between polymer surfaces subjected to such SDecies are much stronger than bonds between untreated surfaces, 4) the chemical modification of the surface creates a reactive surface to which a thin layer of another polymer may be bonded by glow discharge polymerization.

scholarly journals Spatial Non-uniformity in Discharges in Low Pressure Helium and Neon

1987 ◽  
Vol 40 (3) ◽  
pp. 383 ◽  
Author(s):  
J Fletcher ◽  
PH Purdie
Keyword(s):  
Monte Carlo Simulation ◽  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
Low Pressure ◽  
Photon Flux ◽  
Cross Section Data ◽  
Section Data ◽  
Neon Gas ◽  
Wavelength Distribution

Low current, low pressure, steady state Townsend discharges in helium and neon gas have been investigated using the photon flux technique. Such discharges have been found to exhibit spatial non-uniformity resulting in luminous layers throughout the discharge. The separation and structure of these layers has been investigated experimentally in both gases along with the wavelength distribution of the photon flux. A Monte Carlo simulation of the discharge in neon has been used to gain information on the cross sections necessary to describe these discharges. It is found that direct excitaton of ground state atoms to the resonance level of each gas is less than indicated by some published cross section data.

The Pressure Field at the Output From a Low Pressure Exhaust Hood and Condenser Neck of the 1090 MW Steam Turbine: Experimental and Numerical Research

2018 ◽  
Author(s):  
Michal Hoznedl ◽  
Antonín Živný ◽  
Aleš Macálka ◽  
Robert Kalista ◽  
Kamil Sedlák ◽  
...  
Keyword(s):  
Boundary Condition ◽  
Steam Turbine ◽  
Cross Section ◽  
Static Pressure ◽  
Cooling Water ◽  
Low Pressure ◽  
Maximum Temperature ◽  
Angle Distribution ◽  
Exhaust Hood ◽  
Last Stage

The paper presents the results of measurements of flow parameters behind the last stage of a 1090 MW nominal power steam turbine in a nuclear power plant. The results were obtained by traversing a pneumatic probe at a distance of about 100 mm from the trailing edges of the LSB (Last Stage Blade). Furthermore, both side walls as well as the front wall of one flow of the LP (Low Pressure) exhaust hood were fitted with a dense net of static pressure taps at the level of the flange of the turbine. A total of 26 static pressures were measured on the wall at the output from the LP exhaust hood. Another 14 pressures were measured at the output from the condenser neck. The distribution of static pressures in both cross sections for full power and 600 and 800 MW power is shown. Another experiment was measured pressure and angle distribution using a ball pneumatic probe in the condenser neck area in a total of four holes at a distance up to 5 metres from the neck wall. The turbine condenser is two-flow design. In one direction perpendicular to the axis of the turbine cold cooling water comes, it heats partially. It then reverses and it heats to the maximum temperature again. The different temperature of cooling water in the different parts of the output cross section should influence the distribution of the output static pressure. Differences in pressures may cause problems with uneven load of the tube bundles of the condenser as well as problems with defining the influential edge output condition in CFD simulations of the flow of the cold end of the steam turbine Due to these reasons an extensive 3D CFD computation, which includes one stator blade as well as all moving blades of the last stage, a complete diffuser, the exhaust hood and the condenser neck, has been carried out. Geometry includes all reinforcing elements, pipes and heaters which could influence the flow behaviour in the exhaust hood and its pressure loss. Inlet boundary conditions were assumed for the case of both computations from the measurement of the flow field behind the penultimate stage. The outlet boundary condition was defined in the first case by an uneven value of the static pressure determined by the change of the temperature of cooling water. In the second case the boundary condition in accordance with the measurement was defined by a constant value of the static pressure along all the cross section of the output from the condenser neck. Results of both CFD computations are compared with experimental measurement by the distribution of pressures and other parameters behind the last stage.

Study on SCWR Fuel Assembly Design With Thermal-Hydraulic and Neutron-Physical Characteristics

2010 ◽  
Author(s):  
Zhenyang Li ◽  
Tao Zhou ◽  
Canhui Sun ◽  
Xiaozhuang Liu
Keyword(s):  
Fuel Assembly ◽  
Cross Section ◽  
Power Distribution ◽  
Neutron Cross Section ◽  
Physical Characteristics ◽  
Supercritical Pressure ◽  
Light Water ◽  
Assembly Design ◽  
Temperature Distributions ◽  
Parallel Channels

Physical characteristics of the coolant in the Supercritical-pressure Light Water Cooled Reactor (SCWR) vary greatly near the pseudo-critical point, which will cause variations of core neutron cross section and then bring about power perturbation. Further it will prompt the corresponding thermal parameters of supercritical water changed, and form feedback action, finally resulting in intensely coupled thermal-hydraulics and neutron-physical. Proper fuel assembly has been selected as research object, and the model of multiple parallel channels has been established. In view of this model, using DRAGON code for neutron-physical calculations and developing corresponding thermal-hydraulic programs, and then achieve coupling them through appropriate data interface, the calculation platform established. Finally the power distribution and the corresponding parameters temperature distributions in the model have been predicted. On account of deficiencies reflected in calculations, such as the heterogeneous power distribution, fuel assembly geometry has been changed, for instance the proper peripheral moderator wall has been added based on the preceding assembly, then do the coupling calculations and analyze the results. Comparisons between different results have been made, and the expected aim has been reached, which can prove the rationality of assembly modifications and meanwhile prove the usability of the calculation platform. Thus, modified assembly and the calculation platform could be the calculation foundation in future designs of SCWR.

A Novel Multibranched Chromophore Containing Carbazole Moiety for Two-Photon Microfabrication

2012 ◽  
Vol 485 ◽  
pp. 566-569
Author(s):  
Zhi Yuan Hu ◽  
Fu Quan Guo ◽  
Hao Liang ◽  
Bin Guo
Keyword(s):  
Cross Section ◽  
Laser Power ◽  
Photon Absorption ◽  
Structural Motif ◽  
Incident Laser ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Incident Laser Power ◽  
Potential Applications ◽  
Pentaerythritol Triacrylate

A novel multibranched chromophore containing carbazole moiety，4, 4´, 4´´-tris(9-carbazyl-trans-styryl) triphenylamine (TCSTPA)，was synthesized and characterized by 1HNMR and elemental analysis. A larger two-photon absorption (TPA) cross section of the chromophore was obtained as high as 2350 GM compared to that of the traditional linear chromophore when pumped by a femtosecond laser at 800 nm. Microstructure based on TPA induced polymerization with a spatial resolution of submicron was fabricated under much lower incident laser power using TCSTPA as a TPA photoinitiator and a multifunctional resin of pentaerythritol triacrylate (PETA) as a polymerizable monomer. The result indicates potential applications of this kind of chromophores with multibranched structural motif in the fabrication of polymer and functional microdevices.

Preparation of Stoichiometric TiNx Films by Laser CVD with Metalorganic Precursor

2011 ◽  
Vol 239-242 ◽  
pp. 318-321
Author(s):  
Yan Sheng Gong ◽  
Wei Zhou ◽  
Rong Tu ◽  
Takashi Goto
Keyword(s):  
Chemical Vapor Deposition ◽  
Cross Section ◽  
Deposition Rate ◽  
Vapor Deposition ◽  
Laser Power ◽  
Single Phase ◽  
Heating Temperature ◽  
Chemical Vapor ◽  
Laser Cvd ◽  
Source Materials

Nearly stoichiometric TiNxfilms were deposited on Al2O3substrates by laser enhanced chemical vapor deposition (CVD) with tetrakis (diethylamido) titanium (TDEAT) and ammonia as the source materials. Emphases were given on the effects of laser power (PL) and pre-heating temperature (Tpre) on the composition and deposition rate of TiNxfilms. Single phase of TiNxfilms with columnar cross section were obtained. The ratio of N to Ti in TiNxfilms increased with increasingPLand was close to stoichiometric atPL> 150 W. The deposition rate of TiNxfilms with a depositing area of 300 mm2was about 18-90 µm/h, which decreased with increasingPLandTpre.

Effect of Residual Stress on Si-Consumption During W-Deposition by LPCVD

1990 ◽  
Vol 181 ◽  
Author(s):  
S. H. Lee ◽  
J. J. Lee ◽  
Dong-Wha Kum
Keyword(s):  
Residual Stress ◽  
Cross Section ◽  
Early Stage ◽  
Oxide Thickness ◽  
Low Pressure ◽  
Significant Enhancement ◽  
Si Substrate ◽  
Patterned Wafers

ABSTRACTThe effect of stress on W-deposition at low pressure by Si-reduction of WF6 has been studied on patterned wafers utilizing cross-section SEM and cross-section TEM. Si-consumption and encroachment formation at the Si/Si02 interface was analyzed as a function of the oxide thickness, which changes the residual stress of the Si-substrate beneath the SiO2-layer. At the edge of the SiO2-layer, significant enhancement of W-deposition was observed from the early stage of W-metallization. Penetration of W into the Si-substrate beneath the edge showed strong dependency upon the oxide thickness, while penetration along the SiO2/Si interface (i.e. encroachment) did not. It has been analyzed that early stage of W-deposition was strongly affected by residual stress in the Si-substrate, and contact between WF6 and Si will be much easier through porous W-film and the W/Si interface, where the existence of microvoids is expected.

scholarly journals A Modified Approach for the Blumlein-line Laser Power Calculations: Electrical and Optical Power Waveforms

2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Mohamed Otman Twati ◽  
Abubaker B. Otman
Keyword(s):  
Laser Power ◽  
Laser System ◽  
Optical Power ◽  
Theoretical Work ◽  
Electrical Circuit ◽  
Nitrogen Laser ◽  
Power Calculations ◽  
Decoupling Approach ◽  
Laser Systems ◽  
Blumlein Line

In this paper, a modified approach for output power calculations of the nitrogen laser system is reported. The power calculations is based on the distributed parameter model of the Blumlein-line circuit along with the decoupling approach of the laser rate equation from the electrical circuit equations. The general laser power assumption is considered in calculating the output optical power. The effect of the laser gap inductance on both the electrical and optical power waveforms is simulated and discussed. The theoretical work presented here is quite general and could be applied to many other fast discharges laser systems, such as CO2 and copper vapor lasers.

scholarly journals Research on Residual Stress Distribution in Different Areas of Laser-MAG Arc Hybrid Welding by Numerical Simulation

2022 ◽  
Vol 2160 (1) ◽  
pp. 012026
Author(s):  
Xiaoyan Qian ◽  
Xin Ye ◽  
Xiaoqi Hou ◽  
Haohao Jing ◽  
Peilei Zhang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Cross Section ◽  
Laser Power ◽  
Residual Stress Distribution ◽  
Bottom Surface ◽  
Hybrid Welding ◽  
Welding Seam ◽  
Mixed Zone ◽  
Arc Power

Abstract In this research, through experiments and numerical simulations, the residual stress distribution of the top and bottom surfaces of the laser (TruDisk16002)-arc (MAG) hybrid welding seam and the weld cross-section are studied. The results show that when the arc power is 6.5KW and the laser power is 7.5KW, the weld is formed well. The residual stress on the bottom surface near the weld is higher than that on the top surface. The laser zone in the center of the weld has the largest residual stress, the arc zone is smaller, and the mixed zone is the smallest. The laser zone has the largest residual stress at the fusion line and the heat-affected zone, followed by the mixed zone, and the arc zone is the smallest. followed by the mixed zone, and the arc zone has the smallest.

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