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Computational fluid dynamics uses numerical methods and algorithms to solve and analyse problems that involve fluid flows. Computers may be used to perform the calculations required to simulate the interaction of liquids and gasses with a surface defined by boundary conditions. Thermodynamics is the science of the relationship between heat, work, temperature, and energy. Computational modelling for microchannel reactor design was performed to investigate the effects of various factors on the efficiency and performance of an autothermal reforming system. The yield and productivity from the chemical process were determined by performing computational fluid dynamics and thermodynamic analysis. Strength and weakness were assessed under different reaction conditions. Design recommendations were provided and operation strategies were mapped out. The results indicated that operation at millisecond contact times is feasible, but optimisation of reaction conditions is necessary to balance efficiency and performance. The conversion to hydrogen is influenced greatly by the feed composition, which must be controlled precisely within certain needed limits to maximize the yield and productivity from the autothermal reforming process while avoiding the problems of combustion or explosion. Additionally, the efficiency difference between feed compositions is determined by thermodynamic analysis. The calculated output power of the autothermal reforming reactor is of the order of thousands of kilowatts per cubic meter.

It can be considered that electric generating power from solar energy is an essential topic in the energy field. Several environmental factors affect the energy production of solar cells. Dust accumulation is one of the main factors which significantly negatively influences output energy. However, this topic is not investigated extensively, despite its significant impact, especially in arid areas such as Iraq. In this research paper, both theoretical and experimental techniques were applied to investigate the effect of accumulated dust particles on the efficiency of photovoltaic PV systems. An on-grid photovoltaic system was selected to achieve the experimental work. The results proved the negative effect of dust particles on the performance of the solar cell. Based on the obtained results, a new relationship was introduced between efficiency degradation and the amount of dust that accumulated on the surfaces of cells. This correlation is considered a necessity to find the characteristics of PV solar systems to improve their performance and efficiency. The new correlation introduced in this paper can be considered a promising prediction tool to estimate the characteristics of photovoltaic solar cells under different actual environment working conditions. The output power of the cleaned array system increased by 5–26% compared with the untreated system over the test period. Furthermore, the performance ratio (PR) was enhanced within the cleaned array system by 3 to 6 compared with the uncleaned array. A significant formula introduced the connection between the actual output power of the PV systems and the environmental condition (dust accumulation), where it can be considered as feedback to keep the performance in a steady status, which means obtaining the highest output power.

It is well established that renewable energy resources for electricity generation are free. In hot areas, solar energy has become one of the major interests of researchers and specialists. This paper aims to experimentally investigate the maximum voltage generation of a thermoelectric generator (TEG) panel. This panel was built from many TEG modules that are connected in series and in parallel. The panel was exposed to high heat due to solar radiation during summer, either directly or through a Fresnel lens. The other side of the TEG panel was cooled using tap water that was passed through aluminum heat exchangers in an active cooling method. It was found that the maximum open-circuit voltage of this TEG panel using a Fresnel lens was 9.35 V. With no lens, it was 11.75 V at 14:00 h local time. The experiments were done during a sunny July period in Iraq. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.

Harvesting ocean wave energy through carbon-based materials, particularly graphene, is receiving increasing attention. However, the complicated fabrication process and the low output power of the present monolayer graphene-based wave energy generators limit their further application. Here, we demonstrate the facile fabrication of a new type of wave energy generator based on graphene/TiO2 nanoparticle composite films using the doctor-blading method. The developed wave energy harvesting device exhibits a high open-circuit voltage of up to 75 millivolts and a high output power up to 1.8 microwatts. A systematic study was conducted to explore the optimal conditions for the energy harvesting performance., QC 20221222

Prediction of photovoltaic (PV) performance is important for energy management practices. The power produced from renewable energy sources is uncertain in nature as it is subjected to continuous changing weather conditions. Hence accurate prediction of output power from these sources is difficult task. In this paper Adaptive Neuro-Fuzzy Inference System (ANFIS) based forecast model for predicting the PV power generation is developed. The proposed model is based on back propagation hybrid learning algorithm of ANFIS with four inputs and one output. Experimentally measured input data of 20 KW. PV system installed at Nashik, Maharashtra, India is used for developing prediction model. The inputs are solar radiation (Rad), ambient temperature (Temp), relative humidity (Hum) and day of year for measurement. Photovoltaic power generation is the output of the model. This data is utilized in the training and testing of the proposed model. Results obtained confirm the ability of the developed ANFIS model for assessing the power produced with reasonable accuracy. A comparative study has done between regression analysis and ANFIS. This shows that the ANFIS-model performs much better than regression. The advantage of the ANFIS model is that they do not need more parameters or complicate calculations unlike implicit models. The developed model could be used to forecast the profile of the produced power in uncertain whether conditions. The error due to ANFIS prediction model for energy produced from the given system considered in this research is 6.14 % which is much better when compared with regression analysis whose error is 16 %.  The results indicate that this model can potentially be used to estimate and predict PV solar output power.

Prediction of photovoltaic (PV) performance is important for energy management practices. The power produced from renewable energy sources is uncertain in nature as it is subjected to continuous changing weather conditions. Hence accurate prediction of output power from these sources is difficult task. In this paper Adaptive Neuro-Fuzzy Inference System (ANFIS) based forecast model for predicting the PV power generation is developed. The proposed model is based on back propagation hybrid learning algorithm of ANFIS with four inputs and one output. Experimentally measured input data of 20 KW. PV system installed at Nashik, Maharashtra, India is used for developing prediction model. The inputs are solar radiation (Rad), ambient temperature (Temp), relative humidity (Hum) and day of year for measurement. Photovoltaic power generation is the output of the model. This data is utilized in the training and testing of the proposed model. Results obtained confirm the ability of the developed ANFIS model for assessing the power produced with reasonable accuracy. A comparative study has done between regression analysis and ANFIS. This shows that the ANFIS-model performs much better than regression. The advantage of the ANFIS model is that they do not need more parameters or complicate calculations unlike implicit models. The developed model could be used to forecast the profile of the produced power in uncertain whether conditions. The error due to ANFIS prediction model for energy produced from the given system considered in this research is 6.14 % which is much better when compared with regression analysis whose error is 16 %.  The results indicate that this model can potentially be used to estimate and predict PV solar output power.

This paper investigates the impact of the thyristor commutation time on the peak currents and the active-power capability of the hybrid alternate-common-arm converter (HACC). This converter employs director thyristors for the alternate connection of a common arm in parallel to the main arms. The parallel connection enables current sharing among the arms, which allows the HACC to transfer higher output power without increasing the peak arm current. It is shown that the active-power capability of the HACC is doubled for a certain current-sharing factor, which, however, is altered by the thyristor commutation time. Therefore, the impact of the commutation time on the active-power capability of the HACC is investigated theoretically. Finally, this analysis is verified by simulation results., QC 20200217

Cw laser oscillation of ruby at 694 nm in linear and ring resonators is reported for the first time, pumped with a 1 W laser diode at 405 nm as well as 445 nm. The ruby laser operates at room temperature with a threshold of 200 mW at 405 nm and 400 mW at 445 nm. So far output powers up to 36 mW have been achieved pumped at 405 nm. With the ruby ring laser highly coherent single frequency operation will be possible. © 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.

The potential of impact-driven frequency up-conversion in a MEMS EH is evaluated using numerical simulations. The investigated design is compared to a conventional cantilever EH in terms of output power and loss rate. The upshifting can lead to significantly increased output power at a similar loss rate but as the time scale for the loss is long, the benefit is limited. This also requires an effective upshifting process. The design of the impact introduces a length scale that must be selected with excitation, gravity, and pre-stress taken into account. This makes this type of EH application-dependent as a non-optimal choice may result in low output power.

Class-D audio amplifiers seem to be a perspective way of development of electronics as they can obtain excellent power efficiency together with good performance characteristics. Moreover, they can be easily integrated on a single chip, resulting in clear, comprehensive and non-reckless construction of the audio amplifier. Because the power efficiency is considerably high, some designs even do not need any heat sink, since the heat dissipation can be fully provided by the chip package. In this paper a construction of such an amplifier, being based on the integrated circuit TPA3122, is described. This construction has been developed at Tomas Bata University in Zlin, using conventional component base. Moreover, the paper provides a comparison of the measured performance of the amplifier to the theoretical values provided by the manufacturer of the chip. © 2018, Danube Adria Association for Automation and Manufacturing, DAAAM. All rights reserved.

The potential of impact-driven frequency up-conversion in a MEMS EH is evaluated using numerical simulations. The investigated design is compared to a conventional cantilever EH in terms of output power and loss rate. The upshifting can lead to significantly increased output power at a similar loss rate but as the time scale for the loss is long, the benefit is limited. This also requires an effective upshifting process. The design of the impact introduces a length scale that must be selected with excitation, gravity, and pre-stress taken into account. This makes this type of EH application-dependent as a non-optimal choice may result in low output power.

An Auxiliary Power Unit (APU) for HOPE (H-2 Orbiting Plane) was examined to elucidate characteristic features of a 2-liquid system. The following conditions were assumed: output power = 60 HP, working time = 78 min, and duty = 35 min for 0 HP, 30 min for 12 HP, and 10 min for 60 HP. Critical requirements for HOPE APU were small size and lightweight. The main factor which determined the weight and volume of APU was loaded fuel because in most systems the loaded fuel was heavier than APU. In a 2-liquid system, ignition gas temperature was controlled between 1,600 and 4,000 K by varying the mixture ratio. Thus it was possible to reduce the fuel weight by raising the ignition gas temperature. The fuel consumption of 2-liquid system of hydrazine plus NTO (nitrogen tetroxide) was found to be about 75 percent of a 1-liquid system of hydrazine anhydride and that of liquid hydrogen plus liquid oxygen to be 32 percent of the 1-liquid system. Since a turbine must be made from ceramic materials in a 2-liquid system due to high ignition temperature, development risks tended to be high. If an equal weighting factor for all the items compared was assumed, the weight reduction of fuel turned out to be about 10 percent of the total weight of a 2-liquid system. Therefore, it was concluded that a 2-liquid system could offer essentially no advantage., HOPE(H-2ロケット打ち上げ型有翼回収機)用の補助動力源(APU)を検討して2液式システムの特徴を明確にした。前提条件は、出力60HP、使用時間78分、デューティは出力ゼロで35分、12HPで30分、60HPで10分であった。HOPE-APUの重点課題は、小型、軽量であり、ほとんどのシステムにおいてAPU本体重量より搭載燃料重量のほうが大きく、APUシステムの重量および容積を決定する大きな要因は搭載燃料にあった。2液式では、その混合比を変えることにより燃焼ガス温度を1,600〜4,000Kまで制御可能で、燃焼ガス温度を上げることにより燃料重量を小さくできた。無水ヒドラジン1液式に比べ、2液式のヒドラジン+NTO(4酸化2窒素)は約75% 、液体水素+液体酸素は約32%の燃料消費量になることがわかった。2液式の場合は燃焼温度が高いために、タービンのセラミックス化が必要になり、開発リスクが大きかった。2液式の制御性は1液式に比べて複雑になる。比較項目の重みを同等と仮定すると、2液式による燃料重量の削減はシステム重量の約1割に留まり、メリットがないと判断した。

type:text, In this paper, analytical expressions and design equations are presented for the class-E amplifier with the MOSFET nonlinear drain-source and linear gate-drain parasitic capacitances along with the external linear shunt capacitance. The class-E amplifier characteristics are presented as functions of the ratio of the sum of the external linear shunt capacitance and the MOSFET linear gate-drain capacitance to the MOSFET drain-source junction capacitance when the switch voltage is zero. Although the effect of the MOSFET linear gate-drain capacitance is similar to that of the external linear shunt capacitance on the design of the class-E amplifier with the square input voltage, the difference between their effects should be considered for the sinusoidal input voltage, which is one of the most important suggestions in this paper. Additionally, analytical expressions of output power capability is given, which is considerable affected by the external linear shunt capacitance. Two design examples are presented with taken into account the output power as design specification at 8.7-W output power and 4-MHz operating frequency along with the PSpice-simulations and experimental waveforms.

A chirped-pulse mm-wave spectrometer was constructed using a real-time digitizer and amplified multiplier chains. The real-time digitizer performance greatly increased data throughput relative to previous digitizers. Spectral data on methanol at mm-wave frequencies was obtained and used to optimize chirped-pulse bandwidth, duration, and sample pressure. Efforts to miniaturize the sample cell proved unsuccessful due to failure of the mm-wave components. The primary technical hurdles to overcome for future work are the low available output powers of the multiplier chains as well as the low power handling capabilities of the mm-wave receiver components., The original document contains color images.

The editors introduce the focus issue on "Advanced Solid-State Lasers (ASSL) 2013," which is based on the topics presented at a congress of the same name held in Paris, France, from October 27 to November 1, 2013. This focus issue, jointly prepared by Optics Express and Optical Materials Express, includes 21 contributed papers (18 for Optics Express and 3 for Optical Materials Express) selected from the voluntary submissions from attendees who presented at the congress and have extended their work into complete research articles. We hope this focus issue offers a good snapshot of a variety of topical discussions held at the congress and will contribute to the further expansion of the associated research areas., QC 20140613

BH-QCLs were fabricated with regrowth of semi-insulating InP:Fe in hydride vapor phase epitaxy reactor. Two types of lateral ridge QCL designs were considered: (i) closely spaced ridges with double trenches and (ii) widely and uniformly spaced ridges. The etched depth varies from 6 to 15 μm in the former and 6 to10 μm in the latter. Double trenches of about 14 μm deep take only < 40 minutes to planarize while the same time is needed to planarize about 8 μm deep trenches with uniform ridges. In any case the achieved growth rate is higher by at least one order of magnitude than that can be achieved in MBE and MOVPE. Some fabricated BH-QCLs are characterized and they exhibit spatially monomode (TMoo) laser with an output power of as high as 2.4 W and wall plug efficiency of ∼8-9% at RT under CW operation., QC 20150604

In this paper we analyze the influence of intracell traffic in a GSM cell on the base station output power. It is proved that intracell traffic increases this power. If offered traffic is small, the increase of output power is equal to the part of intracell traffic. When the offered traffic and, as the result, call loss increase, the increase of output power becomes less. The results of calculation are verified by the computer simulation of traffic process in the GSM cell. The calculation and the simulation consider the uniform distribution of mobile users in the cell, but the conclusions are of a general nature.

In this paper we analyze the influence of intracell traffic in a GSM cell on the base station output power. It is proved that intracell traffic increases this power. If offered traffic is small, the increase of output power is equal to the part of intracell traffic. When the offered traffic and, as the result, call loss increase, the increase of output power becomes less. The results of calculation are verified by the computer simulation of traffic process in the GSM cell. The calculation and the simulation consider the uniform distribution of mobile users in the cell, but the conclusions are of a general nature.

In this paper we analyze the influence of intracell traffic in a GSM cell on the base station output power. It is proved that intracell traffic increases this power. If offered traffic is small, the increase of output power is equal to the part of intracell traffic. When the offered traffic and, as the result, call loss increase, the increase of output power becomes less. The results of calculation are verified by the computer simulation of traffic process in the GSM cell. The calculation and the simulation consider the uniform distribution of mobile users in the cell, but the conclusions are of a general nature.

This thesis addresses the potential of implementing a predriver for class-D power amplifier for WLAN in 65 nm CMOS technology. In total, eight different predrivers have been created using Cadence Virtuoso CAD tools. All designs have been tested using Agilent's Advance Design System (ADS) and simulated using the ADS-Cadence dynamic link. Furthermore, a comparison between the eight designs and the reference design has been done. The examined parameters were output power (Pout), efficiency, and effective area consumption. The simulation results show that most of the proposed designs obtain higher output power, higher efficiency, and lower effective area than the reference design. For the reference design, output power of 34.2 dBm, efficiency of 20.8 %, and effective area of 63952 um2 were obtained. For design No.1, the effective area was 31511um2, which was almost half of the area occupied by the reference design. For design No.3, the efficiency was 71.2 %, which was almost 3 and half times higher than the efficiency of the reference design. Furthermore, all designs, except design NO.7, gave more or less the same output power (around 34.4 dBm).

This thesis addresses the potential of implementing a predriver for class-D power amplifier for WLAN in 65 nm CMOS technology. In total, eight different predrivers have been created using Cadence Virtuoso CAD tools. All designs have been tested using Agilent's Advance Design System (ADS) and simulated using the ADS-Cadence dynamic link. Furthermore, a comparison between the eight designs and the reference design has been done. The examined parameters were output power (Pout), efficiency, and effective area consumption. The simulation results show that most of the proposed designs obtain higher output power, higher efficiency, and lower effective area than the reference design. For the reference design, output power of 34.2 dBm, efficiency of 20.8 %, and effective area of 63952 um2 were obtained. For design No.1, the effective area was 31511um2, which was almost half of the area occupied by the reference design. For design No.3, the efficiency was 71.2 %, which was almost 3 and half times higher than the efficiency of the reference design. Furthermore, all designs, except design NO.7, gave more or less the same output power (around 34.4 dBm).

Laser ablation (LA) with a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser is a minimally invasive approach able to achieve a high rate of complete tissue necrosis. In a previous study we described the feasibility of EUS-guided Nd:YAG pancreas LA performed in vivo in a porcine model.

he growing need for obtaining electrical energy through renewable energy sources such as solar energy have lead to significant technological developments in the production of the basic element of PV conversion, the solar cell. Basically, a solar cell is a p-n junction whose characteristics have a great influence on its output parameters, primarily efficiency. Defects and impurities in the basic material, especially if located within the energy gap, may be activated during its life time, becoming traps for optically produced electron-hole pairs and, thus, decreasing the output power of the cell. All of the said effects could be induced in many ways over a life time of a solar cell and are consistent with the ef ects that radiation produces in semiconductor devices. The aim of this paper is to investigate changes in the main characteristics of solar cells, such as efficiency, output current and power, due to the exposure of solar systems to different (hostile) radiation environment.

Herein is reported development and testing of a life cycle analysis (LCA) procedure for assessing the environmental impact of induction motors. The operating conditions of a given industrial application are defined by the mechanical power required, operating hours and service life of the three-phase induction motor involved. Based on manufacturer’s data mainly,different three-phase induction motors for various sets of operating conditions, including oversizing, have been selected. To quantify the environmental impact of each motor, the Methodology for the Ecodesign of Energy Using Products (MEEUP) was applied, according to the quantity of each of the motor’s main constituent materials used in the production phase, and to the two operating variables that directly influence the LCA results: output power and efficiency. The procedure was applied to different three-phase induction motors representing two efficiency categories (IE1 and IE2) and considering different oversizing possibilities. The total environmental impact of each motor was determined based on the production, service life and end-of-life phases. The best motor option was identified for different operating conditions. Given the potential for energy savings in electric motors, LCA-based environmental impact assessment should be performed when different motors are being evaluated for a given industrial application., Postprint (published version)

VBGs can efficiently be used to mitigate the spectrally broad output from cryogenically cooled Yb-fiber lasers. We extract 11.5-W of output power in spectral window of less than 0.4-nm with 14.5-W of launched pump light., QC 20110302

Two identical highly reflective volume Bragg gratings are used in tandem to lock an ytterbium doped fiber laser. A narrow linewidth (<2GHz) and high efficiency (>70%) is achieved with output powers above 7W., QC 20150421

Instruments for analyzing radio signals are very expensive and their full capacity is seldom used outside the research and development and the type approval departments. Instrument manufacturers have historically integrated the hardware and the software into a single unit. But some instrument manufacturers are beginning to change this. The software is moved to a PC and the hardware samples the time continuous signal and sends it to the computer for analysis or for saving it on a file. Since the data from the hardware is in a raw format this opens up for other than the instrument manufacturer to supply the software. This thesis presents algorithms for calculating power, phase error and frequency error. It is shown that the results from these algorithms are comparable to the results from commercial analysis software. It is concluded that it is possible to create own analysis software at a reasonable cost with the possible downside of it being slower than commercial software.

Instruments for analyzing radio signals are very expensive and their full capacity is seldom used outside the research and development and the type approval departments. Instrument manufacturers have historically integrated the hardware and the software into a single unit. But some instrument manufacturers are beginning to change this. The software is moved to a PC and the hardware samples the time continuous signal and sends it to the computer for analysis or for saving it on a file. Since the data from the hardware is in a raw format this opens up for other than the instrument manufacturer to supply the software. This thesis presents algorithms for calculating power, phase error and frequency error. It is shown that the results from these algorithms are comparable to the results from commercial analysis software. It is concluded that it is possible to create own analysis software at a reasonable cost with the possible downside of it being slower than commercial software.

A novel defected ground structure (DGS) was designed and applied to a flip-chip integrated millimeter wave oscillator. The characteristics of two oscillators with and without DGS were analyzed and compared. Measurement data shows that the phase noise of the oscillator with DGS is reduced by 4 similar to 6 dB, and the output power of the oscillator is increased by 0.8 dBm in comparison with the oscillator without DGS. It is found that, when DGS is embedded in the resonant tank and the output terminal of an oscillator, the phase noise can be reduced and the output power will be enhanced. 設計了一種新型的缺陷接地結構(DGS)并將之應用到倒扣集成毫米波振蕩器中.分析并比較了具有DGS結構和沒有DGS結構的兩種振蕩器性能.測試數據顯示具有DGS結構的振蕩器與沒有DGS結構的振蕩器相比,相位噪聲降低4~6dB,輸出功率增加0.8dBm.研究結果表明DGS結構嵌入到振蕩器的諧振電路和輸出端時,振蕩器的相位噪聲降低且輸出功率增大.

A fully integrated 0.18 μm 1P6M CMOS power amplifier using internal frequency doubling is presented. Two chips were measured, one stand-alone PA and one PA with a VCO on the same chip. Since the PA and VCO operate at different frequencies, this configuration is suitable for direct-upconversion or low-IF upconversion since oscillator pulling is reduced. The maximum output power is 15 dBm, and the maximum drain efficiency is 10.7% at an output operating frequency of 2.4 GHz

We report on the fabrication and high-frequency characterization of AlGaN/GaN high-electron mobility transistors (HEMTs) grown by molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD). In devices with a gate length of 160 nm, a record power density of 10.5 W/mm with 34% power added efficiency (PAE) has been measured at 40 GHz in MOCVD-grown HEMTs biased at V-DS = 30 V. Under similar bias conditions, more than 8.6 W/mm, with 32% PAE, were obtained on the MBE-grown sample. The dependence of output power, gain, and PAE on gate and drain voltages, and frequency have also been analyzed.

We report on the fabrication and high-frequency characterization of AlGaN/GaN high-electron mobility transistors (HEMTs) grown by molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD). In devices with a gate length of 160 nm, a record power density of 10.5 W/mm with 34% power added efficiency (PAE) has been measured at 40 GHz in MOCVD-grown HEMTs biased at V-DS = 30 V. Under similar bias conditions, more than 8.6 W/mm, with 32% PAE, were obtained on the MBE-grown sample. The dependence of output power, gain, and PAE on gate and drain voltages, and frequency have also been analyzed.

In this thesis the models of Si-LDMOS transistors have been investigated with Agilent EEsof ADS version 2002a for operation in the 2-6 GHz frequency range. The first one is the Motorola’s (MRF21010) model based on a 30 mm prototype of a Si-LDMOS transistor. The second one is a model based on a 1 mm prototype of Si-LDMOS transistor developed at Chalmers University. Large-signal simulations of Chalmers’ model have demonstrated results, which lead to the conclusion that,this model cannot be efficiently utilised for design for a PA in the 2-6 GHz frequency range. However, additional simulations with reduced Rd (drain losses) show the deep impact of this parameter on the main properties of the designed PA. Hence, it is important to take it into account during new processes of Si-LDMOS as well as to improve the CAD model. The final conclusion regarding Si-LDMOS cannot be made just based on these simulation results, since they are not in accordance with the published ones. The next step should be aimed at improving the model and further investigation of Si-LDMOS to prove their ability to operate in the 2-6 GHz frequency range.

In this thesis the models of Si-LDMOS transistors have been investigated with Agilent EEsof ADS version 2002a for operation in the 2-6 GHz frequency range. The first one is the Motorola’s (MRF21010) model based on a 30 mm prototype of a Si-LDMOS transistor. The second one is a model based on a 1 mm prototype of Si-LDMOS transistor developed at Chalmers University. Large-signal simulations of Chalmers’ model have demonstrated results, which lead to the conclusion that,this model cannot be efficiently utilised for design for a PA in the 2-6 GHz frequency range. However, additional simulations with reduced Rd (drain losses) show the deep impact of this parameter on the main properties of the designed PA. Hence, it is important to take it into account during new processes of Si-LDMOS as well as to improve the CAD model. The final conclusion regarding Si-LDMOS cannot be made just based on these simulation results, since they are not in accordance with the published ones. The next step should be aimed at improving the model and further investigation of Si-LDMOS to prove their ability to operate in the 2-6 GHz frequency range.

HF mirror metrology is currently costly and time consuming, requiring laser component delivery to an HF laser site, and operation of another HF laser to reach relevant wavelengths. Coherent Technologies, Inc (CTI) has developed a solid state Cr:ZnSe laser pumped by a Tm:YALO laser that provides up to 1.1 W of output power with 1.1 nm linewidth at 2.64 micrometers, an HF laser line. The laser can also tune to other HF laser lines in the wavelength range of 2.64 micrometers to 2.8 micrometers. The Cr:ZnSe laser was used to measure the reflectivity of HF mirror samples provided by TRW. Examples of other possible applications of this source include beam train alignment and preliminary testing of diagnostic subsystems that measure HF laser output power, wavefronts, and beam profiles. Such a direct laser source is simple and can potentially achieve high intensity stability, allowing for a robust and compact HF laser surrogate. Moreover, power scaling is straightforward., This article is from the Proceedings of SPIE v4631, p209-216, 2002. Prepared in cooperation with TRW Space and Technology Division, Redondo Beach, CA. This article is from ADA403173 Gas and Chemical Lasers and Intense Beam Applications III Held in San Jose, CA, USA on 22-24 January 2002

Efficient continuous-wave and passively Q-switched diode-laser-pumped Nd:YAG lasers at 946 nm are reported together with results on highly efficient frequency doubling. Periodically poled KTiOPO4 was employed as the nonlinear material because of its high nonlinearity and its resistance to photorefractive damage. In the blue spectral region we measured 76 mW in continuous wave and 285 mW in the Q-switched mode., QC 20100525

This TOP determines and measures the spurious responses of AM/FM radio receivers by using commonly available test instrumentation. It has general applicability to all receivers, including image, intermediate frequency (IF) feed-through, local oscillator related, and extraneously produced spurious responses. Spurious responses are signals propagated at frequencies outside of the tuned principal response frequency to which the receiver responds with measurable output power. They reveal frequencies where the receiver is most susceptible to undesired signals (jamming).

This abstract discloses a delta wing nozzle assembly for use within a supersonic chemical laser having a plurality of delta wing-shaped elements which substantially increases the mixing rate of the active reactive gaseous ingredients injected into the resonant cavity of the laser. Each of the plurality of delta wing-shaped elements being of a triangular configuration in which the shape thereof is such that the flow of the gaseous ingredients thereover, normal to the leading edge of the triangular-shaped element, is subsonic. This increased mixing rate substantially increases the output power of the laser., Supersedes PAT-APPL-382 324-82, AD-D009 502.

The scope of the report is the result of investigations for cavity designs of a high power gyrotron. To increase gyrotron output power, consideration was given to increased gun cathode diameters and cavity resonators. The investigations found that ohmic heating and mode competition were two primary problems that must be resolved. (Author)

A biharmonic 3-cm-band Gunn-diode oscillator with second harmonic frequency stabilization by an external high-Q resonator is described and test results are given. The oscillator has an output power of 320 mW for a temperature coefficient of frequency of 5·10-7/°C in the temperature range from -50 to +50°C. Frequency stabilization factors of 24 for variations of supply voltage and 14 for load variations with respect to the first harmonic are obtained. The power losses for stabilization are <0.2 dB.

Tématem mé bakalářské práce je návrh nízkofrekvenčního výkonového zesilovače 2 x 50 W/4, pracujícího ve třídě AB, s korekčním předzesilovačem se sterofonním výstupem. Jedná se o standartní řešení koncového stupně ve stereofonní verzi s monolitickým integrovaným obvodem 2 x LM 3886 a standartní řešení korekčního předzesilovače s integrovaným obvodem LM 1036N. Celé řešení je doplněno o modul napájecího zdroje a také je doplněno řešení chlazení všech výkonových prvků. Cílem této práce bylo vytvoření kompletních podkladů pro realizaci funkčního prototypu (schéma zapojení, návrh desky plošného spoje, soupiska součástek, návrh mechanického uspořádání), zhotoveni funkčního prototypu a ověření jeho správné činnosti laboratorním měřením., The topic of my bachelor´s theis is design of class AB audio power amplifier 2 x 50 W/4 with preamplifier and stereo output. The design is standard solution of stereophonic version of power amplifier, with monolithic integrated circuit 2 x LM 3886. The project deals also with preamplifier with integrated circuit LM 1036, calculation of heat sink of power circuits and solution of supply. The aim of this bachelor´s project was make complete design of laboratory prototype (scheme, layout of printed circuit, part list and placemnet, amplifier arrangement), realisation function of prototype and laboratory measurements.

The results of numerical simulation for fast-axial-flow gas discharge CO 2 lasers are presented. Quasi-one-dimensional consideration of the processes for powerful CO 2 lasers with conic discharge tubes shows that laser operation may be more effective in the case of tubes which are narrowed down from anode to cathode provided that gas flow is directed towards the cathode. On the contrary, when tube is narrowed down from cathode to anode, no any advantage in the laser operation may be received. The calculated quantities are in satisfactory agreement with the available experimental data.

In the report the results of numerical simulation of the processes in discharge chambers (DC) of fast flow CO 2 lasers, are presented. The investigations for longitudinal glow discharge (quasi-one-dimensional and two-dimensional flow) using four- and six-temperature models, were performed. Distributions of gas dynamic quantities, densities of charged parti cles, electric field strength, as well as vibrational temperatures of CO 2, N 2 and CO species, within the DC were calcu lated. Quasi-one-dimensional consideration of processes for powerful CO 2 lasers with conic discharge tubes has shown that narrowed along the gas flow tubes must be more effective for laser operation than cylindrical ones. The calculated quantities are in satisfactory agreement with available experimental data.

The results of numerical simulation for fast-axial-flow gas discharge CO 2 lasers are presented. Quasi-one-dimensional consideration of the processes for powerful CO 2 lasers with conic discharge tubes shows that laser operation may be more effective in the case of tubes which are narrowed down from anode to cathode provided that gas flow is directed towards the cathode. On the contrary, when tube is narrowed down from cathode to anode, no any advantage in the laser operation may be received. The calculated quantities are in satisfactory agreement with the available experimental data.

In the report the results of numerical simulation of the processes in discharge chambers (DC) of fast flow CO 2 lasers, are presented. The investigations for longitudinal glow discharge (quasi-one-dimensional and two-dimensional flow) using four- and six-temperature models, were performed. Distributions of gas dynamic quantities, densities of charged parti cles, electric field strength, as well as vibrational temperatures of CO 2, N 2 and CO species, within the DC were calcu lated. Quasi-one-dimensional consideration of processes for powerful CO 2 lasers with conic discharge tubes has shown that narrowed along the gas flow tubes must be more effective for laser operation than cylindrical ones. The calculated quantities are in satisfactory agreement with available experimental data.

peer-reviewed, The continuing trend in switched-mode power supplies clearly leads to the delivery of more output power with an ever increasing number of voltages more efficiently at less cost. Increasing power management requirements, i.e. communication functionalities, contribute significantly to the need for digitally controlled power supplies. While most of these designs still use simple PID compensators, the introduction of more advanced compensation techniques will improve the system performance considerably. However, one reason for the slow adoption of digital power converters is the lack of proper design tools for advanced digital controllers. This issue is addressed in this thesis where an automated design procedure based on Generalized Predictive Control (GPC) has been developed. Reallife design criteria are used to optimize compensators for application-specific requirements without the need for extensive control expertise. Another issue in today’s digital power systems is the choice of system architecture. Two different concepts are widely used. For high output power demands and fast transient response, multi-phase converters are used which modulate a number of parallel power converters (phases). In this thesis, a new modulator concept is proposed which enables the use of efficiency-improving techniques without increasing the design complexity. The proposed modulator features an internal duty cycle redistribution without complex management overhead. With this modulator, phase shedding can be accommodated together with improved transient behaviour. An alternative concept commonly used today is an intermediate bus architecture with multiple separate point-of-load converters; each controlled by its individual digital core. Digital communication signals between the converters are required to implement advanced control features, such as phase shedding or current sharing. In this thesis, new techniques are proposed which enable the use of these advanced control features withou

Tématem mé bakalářské práce je návrh nízkofrekvenčního výkonového zesilovače 2 x 50 W/4, pracujícího ve třídě AB, s korekčním předzesilovačem se sterofonním výstupem. Jedná se o standartní řešení koncového stupně ve stereofonní verzi s monolitickým integrovaným obvodem 2 x LM 3886 a standartní řešení korekčního předzesilovače s integrovaným obvodem LM 1036N. Celé řešení je doplněno o modul napájecího zdroje a také je doplněno řešení chlazení všech výkonových prvků. Cílem této práce bylo vytvoření kompletních podkladů pro realizaci funkčního prototypu (schéma zapojení, návrh desky plošného spoje, soupiska součástek, návrh mechanického uspořádání), zhotoveni funkčního prototypu a ověření jeho správné činnosti laboratorním měřením., The topic of my bachelor´s theis is design of class AB audio power amplifier 2 x 50 W/4 with preamplifier and stereo output. The design is standard solution of stereophonic version of power amplifier, with monolithic integrated circuit 2 x LM 3886. The project deals also with preamplifier with integrated circuit LM 1036, calculation of heat sink of power circuits and solution of supply. The aim of this bachelor´s project was make complete design of laboratory prototype (scheme, layout of printed circuit, part list and placemnet, amplifier arrangement), realisation function of prototype and laboratory measurements.

Bakalářská práce se zabývá výzkumem flexibilních materiálů k produkci elektřiny za předchozí elektrizace pomocí vytipovaných nábojových budičů blízkého okolí, ve kterém se flexibilní generátory momentálně nachází, čímž dochází k přeměnám energie z jedné na druhou, aniž bychom potřebovali dodávat umělé napájení ze sítě či jiného příslušenství. V reálné aplikaci se počítá se zdroji přirozeně se vyskytujícími, bez nutnosti řídit jejich stavový moment, který se reguluje právě specifickou dochvilností daného prostředí, v závislosti na charakteru aktuální dynamiky jevů vybraného působiště. Výsledný nábojový dipól se odvíjí od mechanismu zelektrování přítomnými vnějšími faktory, jejichž četnost a intenzita nejsou předem stanoveny, pouze statisticky předvídatelné, ale ne zaručeny. Proto se řadí mezi oblast tzv. energy harvesting, jejíž koncept vývoje generátorů energie alternativního původu postupně nahrazuje v přijatelné míře běžně užívané a zatěžující prostředky získávání elektrické energie – alespoň tam, kde je to místně uskutečnitelné a více než komfortní a vhodné., This bachelor thesis is focused on actual research part of energy harvesting technologies – flexible electrical generators, which mean the special generating of electricity using specific flexible materials. The net charge result is affected by the incidental mechanism to transform certain energy form into electrical power and is influenced of material range, which determines what will be harnessed as a source of energy. The energy harvesting is aiming at producing alternative and efficient ways instead of harmful and strained manufacture processing.

Bakalářská práce se zabývá výzkumem flexibilních materiálů k produkci elektřiny za předchozí elektrizace pomocí vytipovaných nábojových budičů blízkého okolí, ve kterém se flexibilní generátory momentálně nachází, čímž dochází k přeměnám energie z jedné na druhou, aniž bychom potřebovali dodávat umělé napájení ze sítě či jiného příslušenství. V reálné aplikaci se počítá se zdroji přirozeně se vyskytujícími, bez nutnosti řídit jejich stavový moment, který se reguluje právě specifickou dochvilností daného prostředí, v závislosti na charakteru aktuální dynamiky jevů vybraného působiště. Výsledný nábojový dipól se odvíjí od mechanismu zelektrování přítomnými vnějšími faktory, jejichž četnost a intenzita nejsou předem stanoveny, pouze statisticky předvídatelné, ale ne zaručeny. Proto se řadí mezi oblast tzv. energy harvesting, jejíž koncept vývoje generátorů energie alternativního původu postupně nahrazuje v přijatelné míře běžně užívané a zatěžující prostředky získávání elektrické energie – alespoň tam, kde je to místně uskutečnitelné a více než komfortní a vhodné., This bachelor thesis is focused on actual research part of energy harvesting technologies – flexible electrical generators, which mean the special generating of electricity using specific flexible materials. The net charge result is affected by the incidental mechanism to transform certain energy form into electrical power and is influenced of material range, which determines what will be harnessed as a source of energy. The energy harvesting is aiming at producing alternative and efficient ways instead of harmful and strained manufacture processing.