A new multi-run technology of laser welding of butt joints of pipes is an alternative to arc welding used in the construction of gas-main pipelines. Conceptually new schemes for performing a root, filling and facing p...
A new multi-run technology of laser welding of butt joints of pipes is an alternative to arc welding used in the construction of gas-main pipelines. Conceptually new schemes for performing a root, filling and facing passes into a special narrowed cutting are presented. The analysis of thermal cycles of heating and cooling of metal, characteristics of hardness, strength and viscosity of welded joints obtained by a specially designed laser welding machine for annular pipes junction in fixed position.
Correction for ‘Highly efficient fullerene/perovskite planar heterojunction solar cells via cathode modification with an amino-functionalized polymer interlayer’ by Qifan Xue et al., J. Mater. Chem. A, 2014, 2, 1959...
Correction for ‘Highly efficient fullerene/perovskite planar heterojunction solar cells via cathode modification with an amino-functionalized polymer interlayer’ by Qifan Xue et al., J. Mater. Chem. A, 2014, rong>2rong>, 19598–19603.
The functional architecture of sonar system is presented and its various functions are briefly described in order to describe the matching circuit in its context and to mark the matching circuit. The matching circuit ...
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ISBN:
(纸本)9781509012732
The functional architecture of sonar system is presented and its various functions are briefly described in order to describe the matching circuit in its context and to mark the matching circuit. The matching circuit can reduce the energy loss and system size of a sonar system by providing the variable reactive power to Sonar system, and also are influenced by the behavior of this load. In this paper, the basic topology of the matching circuit called an adaptive matching circuit is proposed, which is basically composed of variable inductor. First, the power circuit is designed in the power and frequency ranges of interest according to the given specification. Then, the control circuit is also designed through the modeling process. Finally the effectiveness of the proposed matching circuit is proved by using the computer simulation.
In electrochemical machining, the machining accuracy will be affected by stray current. The most effective improvement is to coat the insulation layer on the electrode sidewall so that current can only be accurately r...
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In electrochemical machining, the machining accuracy will be affected by stray current. The most effective improvement is to coat the insulation layer on the electrode sidewall so that current can only be accurately released from the desired area. In this study, the tungsten carbide tool coated by aluminum is performed by the hot dip aluminizing process. Thereafter, which were oxidized by the micro-arc oxidized process to form an aluminum oxide insulating layer to improve extend the life of the electrodes and accurate shape. The electrode is tested in sodium chloride solution and expected to develop a long-life precision electrode with insulation layer for electrochemical machining, reducing the stray electrochemical machining effects to achieve the improving the shape precision of the mold cavity.
In this paper, the root cause and solution of bump deformation failure of memory product in FC (Flip chip) process were studied through experimental and simulation method. After analysis, MUF (Mold under fill) unbalan...
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ISBN:
(纸本)9781509013975
In this paper, the root cause and solution of bump deformation failure of memory product in FC (Flip chip) process were studied through experimental and simulation method. After analysis, MUF (Mold under fill) unbalanced flow was proposed to be the real root cause for this type of failure. In order to verificate it, the simulation method was proposed to explain what level of stress did the bump sufferduring the mold process. What' more, It was found that all the kinds of products with bump deformation have a larger size of die than those products without bump deformation. So the simulation method was proposed to simulate the MUF flow by different size of die. In order to solve the bump deformation problem, the mold process was optimized. The key parameter which effects the bump deformation was found by dOE. Then the profile was optimized and the result showed that it avoided the bump deformation failure a lot.
In this paper, the stress distribution and weak point of Au bonding wire in Chip-On-Board (COB) package were analyzed via a stress released model. In order to find out root cause and factors of it, simulations were pe...
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ISBN:
(纸本)9781509013975
In this paper, the stress distribution and weak point of Au bonding wire in Chip-On-Board (COB) package were analyzed via a stress released model. In order to find out root cause and factors of it, simulations were performed to explain TC failure mechanism and how package styling affected the stress wire suffered. It is found out the stress distribution is related to loop direction. Based on this, new methods were developed to redistribute stress which induced by loop adjustment, neck profile optimization, and encapsulation modification. What is more, the effect of different chip size on stress was also studied. Then, TC performance of each solution were obtained and compared to the normal situation. It demonstrated that TC performance can be obviously enhanced by lowering neck height, increasing neck angle, using small chip and optimizing encapsulation...
Up to now, the non-convex p(0 1/2and 2/3regularization methods have been given analytic solutions and fast closed-form thresholding formulae in recent image deconvolution methods. However, the methods with the other p...
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Parametric array transducers are used for long-range and highly directional communication in underwater environment. The power amplifiers for parametric array transducers should have sufficient linear output character...
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ISBN:
(纸本)9781509012114
Parametric array transducers are used for long-range and highly directional communication in underwater environment. The power amplifiers for parametric array transducers should have sufficient linear output characteristic and high efficiency to avoid communication errors, system heating, and fuel problems. But the conventional power amplifier with fixed source voltage is very low efficient due to large power loss by the big difference between the fixed source voltage and the amplifier output voltage. Thus to solve the problems this paper proposes a new multilevel variable output voltage AC/dC Converter for power supply of power amplifiers used in underwater acoustic sensors. The proposed multilevel variable output voltage AC/dC Converter is composed of two parts. One as the input section is the high efficiency phase-shifted PWM full bridge dC-dC converter to get multiport power sources. The other as the output section is composed of two flying-capacitor 3-level dC-dC converters and a diode bridge circuit to get fast-response and multilevel variable output voltage for an envelope amplifier. Also the paper proposes the power balanced control method between 3-level converters and the voltage balanced algorithm for flying capacitors. Its characteristics should be verified by the detailed simulation results. It is anticipated that the proposed converter will be used very well for power amplifiers used in underwater acoustic sensors.
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