激光诱发活塞的热负荷

活塞的热疲劳性能对柴油发动机的全寿命至关重要。由于能量有限和可控性差等缺点，现有实验系统均不能满意地进行活塞热负荷模拟实验。为此，提出并建立了一套激光诱发活塞热负荷的实验系统。该系统通过对激光束的空间整形，使之投射到活塞表面后诱发的温度场分布满足特定要求。基于PROFIBUS-DP现场总线技术实现了系统集成和实验过程的全反馈控制。针对活塞的典型热负荷条件，即高周热疲劳和热冲击分别进行实验，以模拟正常工作循环和“启动一停车”等热负荷或转速突变工况。通过设置加热一冷却周期或上限下限温度，可以获得相应的热负荷模拟实验效果。研究结果表明，采用经光束整形的激光进行活塞热负荷模拟实验具有周期短、可控性好等优点。 

Generation of long, laminar plasma jets at atmospheric pressure and effects of flow turbulence

Long, laminar plasma jets at atmospheric pressure of pure argon and a mixture of argon and nitrogen with jet length up to 45 fi,Hes its diameter could be generated with a DC are torch by! restricting the movement of arc root in the torch channel. Effects of torch structure, gas feeding, and characteristics of power supply on the length of plasma jets were experimentally examined. Plasma jets of considerable length and excellent stability could be obtained by regulating the generating parameters, including are channel geometry gas flow I ate, and feeding methods, etc. Influence of flow turbulence at the torch,nozzle exit on the temperature distribution of plasma jets was numerically simulated. The analysis indicated that laminar flow plasma with very low initial turbulent kinetic energy will produce a long jet, with low axial temperature gradient. This kind of long laminar plasma jet could greatly improve the controllability for materials processing, compared with a short turbulent are let.

Modeling of a Laminar DC Arc Plasma Torch

In recent years, stable and long laminarplasma jets have been successfully generated, and thus it is possible to achieve low-noise working surroundings, better process repeatability and controllability, and reduced metal-oxidation degree in plasma materials processing. With such a recent development in thermal plasma science and technology as the main research background, modeling studies are performed concerning the DCarcplasmatorch for generating the long laminar argon plasma jet. Two different two-dimensional modeling approaches are employed to deal with the arc-root attachment at the anode surface. The first approach is based on circumferentially uniform arc-root attachment, while the second uses the so-called fictitious anode method. Modeling results show that the highest temperature and maximum axial-velocity at the plasmatorch exit are ～15000 K and ～1100 m/s, respectively, for the case with arc current of 160 A and argon flow rate of 1.95×10{sup}(-4)kg/s.

A 10-GHz bandwidth electroabsorption modulated laser by ultra-low-pressure selective area growth

A novel integration technique has been developed using band-gap energy control of InGaAsP/InGaAsP multi-quantum-well (MQW) structures during simultaneous ultra-low-pressure (22 mbar) selective-area-growth (SAG) process in metal-organic chemical vapour deposition. A fundamental study of the controllability of band gap energy by the SAG method is performed. A large band-gap photoluminescence wavelength shift of 83nm is obtained with a small mask width variation (0-30 mu m). The method is then applied to fabricate an MQW distributed-feedback laser monolithically integrated with an electroabsorption modulator. The experimental results exhibit superior device characteristics with low threshold of 19 mA, over 24 dB extinction ratio when coupled into a single mode fibre. More than 10GHz modulation bandwidth is also achieved, which demonstrates that the ultra-low-pressure SAG technique is a promising approach for high-speed transmission photonic integrated circuits.

Monolithic integration of an InGaAsP-InP strained DFB laser and an electroabsorption modulator by ultra-low-pressure selective-area-growth MOCVD

The design and basic characteristics of a strained InGaAsP-InP multiple-quantum-well (MQW) DFB laser monolithically integrated with an electroabsorption modulator (EAM) by ultra-low-pressure (22 mbar) selective-area-growth (SAG) MOCVD are presented. A fundamental study of the controllability and the applicability of band-gap energy by using the SAG, method is performed. A large band-gap photoluminescence wavelength shift of 88 mn. was obtained with a small mask width variation (0-30 mu m). The technique is then applied to fabricate a high performance strained MQW EAM integrated with a DFB laser. The threshold current of 26 mA at CW operation of the device with DFB laser length of 300 mu m and EAM length of 150 mu m has been realized at a modulator bias of 0 V. The devices also exhibit 15 dB on/off ratio at an applied bias voltage of 5 V.

Characterization of silicon carbide thin films and their use in colour sensor

A series of hydrogenated amorphous silicon carbide (a-Si1-xCx:H) films were prepared by plasma-enhanced chemical vapour deposition (PECVD) using a gas mixture of silane, methane, and hydrogen as the reactive source. The previous results show that a high excitation frequency, together with a high hydrogen dilution ratio of the reactive gases, allow an easier incorporation of the carbon atoms into the silicon-rich a-Si1-xCx:H film, widen the valence controllability. The data show that films with optical gaps ranging from about 1.9 to 3.6 eV could be produced. In this work the influence of the hydrogen dilution ratio of the reactive gases on the a-Si1-xCx:H film properties was investigated. The microstuctural and photoelectronic properties of the silicon carbide films were characterized by Rutherford backscattering spectrometry (RBS), elastic recoil detection analysis (ERDA), and FT-IR spectrometry. The results show that a higher hydrogen dilution ratio enhances the incorporation of silicon atoms in the amorphous carbon matrix for carbon-rich a-Si1-xCx:H films. One pin structure was prepared by using the a-Si1-xCx:H film as the intrinsic layer. The light spectral response shows that this structure fits the requirement for the top junction of colour sensor. (c) 2004 Elsevier B.V. All rights reserved.

MQW electroabsorption modulator-integrated DFB laser modules for high-speed transmission

Details of the design, fabrication and testing of a strained InGaAsP/InGaAsP multiple quantum well (MQW) electroabsorption modulator (EAM) monolithically integrated with a DFB laser by ultra-low-pressure selective area growth (SAG) are presented. The method greatly simplifies the integration process. A study of the controllability of band-gap energy by SAG has been performed. After being completely packaged in a seven-pin butterfly compact module, the device successfully performs 10 Gb s(-1) nonreturn to zero (NRZ) operation on uncompensated transmission span >53 km in a standard fibre with a 8.7 dB dynamic extinction ratio. A receiver sensitivity of -18.9 dBm at a bit error rate (BER) of 10(-10) is confirmed. 10 GHz short pulse trains with 15.3 ps pulsewidth have also been generated.

A 10-GHz Bandwidth Electroabsorption Modulated Laser by Ultra-Low-Pressure Selective Area Growth

A novel integration technique has been developed using band-gap energy control of InGaAsP/InGaAsP multiquantum-well (MQW) structures during simultaneous ultra-low-pressure (22 mbar) selective-area-growth (SAG) process in metal-organic chemical vapour deposition. A fundamental study of the controllability of band gap energy by the SAG method is performed. A large band-gap photoluminescence wavelength shift of 83nm is obtained with a small mask width variation (0-30μm). The method is then applied to fabricate an MQW distributed-feedback laser monolithically integrated with an electroabsorption modulator. The experimental results exhibit superior device characteristics with low threshold of 19mA, over 24 dB extinction ratio when coupled into a single mode fibre. More than 10 GHz modulation bandwidth is also achieved, which demonstrates that the ultra-low-pressure SAG technique is a promising approach for high-speed transmission photonic integrated circuits.

A fixed arc length direct current plasma torch for reduced pressure deposition of thin films

Because of its high energy density direct current(dc)thermal plasmas are widely accepted as a processing medium which facilitates high processing rates high fluxes of radical species the potential for smaller jnstallations a wide choice of reactants and high quench rates[1].A broad range of industrial processing methods have been developed based on dc plasma technology. However,nonstationary features limited new applications of dc plasma in advanced processing, where reliability£¬reproducibility and precise controllability are required£. These challenges call for better understanding of the arc and jet behavior over a wide range of generating parameters and a comprehensive control of every aspect of lhe plasma processing.

焦虑的因素结构及其在中学生中的验证

Since anxiety exists as a certain kind of relation between the subject and his stimuli, present study proposed the criterion that every one of the anxiety’s structural components had to manifest the properties of the relation, not the subject’s properties, and not the stimuli’s properties, too; and that every component must be a bridge from the subject to the object. Several structural models on anxiety were judged by the criterion, and three suited factors were drawn out, which were controllability, importance and urgency. Then through various methods of interview, questionnaire, laboratorial experiment, events graded, the research examined the relations between the three factors and normal anxiety, and explored the interaction of controllability, importance and urgency when they worked together. The results were as the following: 1. The hypothesis that controllability, importance and urgency were the structural components of normal anxiety sounds reasonable, which was supported in different degrees by the results of several secondary research with various methods. 2. With a totally different method of constructing items from the prevalent integrative anxiety inventory, an effective normal anxiety inventory of middle school students was developed based on this theoretical consideration. Reliability and validity research showed that the coefficient of homogeneity and test-retest reliability were high. The construct validity and criterion validity were good enough. The inventory was a useful scale to measure the normal anxiety for middle school students. 3. It’s through their interaction that controllability and importance effect on the level of anxiety which was produced by the relevant event. 4. Anxiety arises with the increasing of importance or urgency. Though there’s a very close connection between controllability and anxiety, the concrete situation is very complicated. Not only is the level of anxiety affected by the interaction of controllability and importance, but when controllability tends to be extremely high or extremely low, importance may also begin to vary with controllability. What’s more, dispositional optimism and self-efficacy still exert influences that cannot be ignored on the relationship between controllability and anxiety. All the results indicated that it was reasonable to regard and study anxiety as a kind of relation between the subject and his environment, and to some extent it’s even necessary if the intention was to clarify the structure of anxiety. Since all the other emotion also exists as a kind of relation between the subject and his stimuli, the wholeness principle which was first proposed and recommended in this study will be of great value to the related researchers. And the interaction between controllability and importance may suggest a valid coping strategy of anxiety.

中美大学生归因偏差的跨文化研究

This research systematically compared Chinese undergraduates with American undergraduates on four kinds of attributional bias: correspondent bias, siuational overattribution, intergroup attributional bias and self-serving attributional bias, and examined the effect of the implicit theories reflecting the cultures on attributional bias. First is analyzed three pairs of opposite implicit theories: dispositionalist theory and situationalist theory, generality and particularity, stressing the positive evaluation of self and despising the positive evaluation of self. It developed the Modern Implicit Theories Inventory and Traditional Implicit Theories Inventory to measure these implicit theories, and the results showed these inventories had satisfactory validity and reliability, and they were suitable for the group comparison of Chinese implicit theories with European-American. At the same time through the test it found Chinese undergraduates agreed all these opposite implicit theories more than American undergraduates. Second, it studied Chinese and American undergraduates' attributional accuracy on locus of causality. The results showed: Chinese and American undergraduates both had the correspondent bias under the different salient situational constraints, and the degree of Chinese and American undergraduates' correspondent bias under the different salient situational constraints had no significant difference' Chinese and American undergraduates both showed the situational overattribution; Chinese undergraduates had more the correspondent bias and situational overattribution than American undergraduates. Third, on the research of Chinese and American undergraduates' intergroup attributional bias, it found Chinese and American undergraduates both had no intergroup attributional bias among kin, friends and strangers, while they both show some favorable outcome effects for these three group actors. The favorable outcome effects were significant on the attributional dimensions of locus of causality and controllability for strangers' behavior, and stability for kin and friends' behavior rating by Chinese undergraduates, and stability for friends' behavior rating by American undergraduates. Fourth, it explored Chinese and American undergraduates' self-serving attributional bias, and the result indicated that Chinese and American undergraduates both showed significant self-serving attributional bias: for outcome effects, Chinese undergraduates' self-serving attributional bias were reflected on the attributional dimensions of locus of causality, stability, controllability and globality, and American undergraduates were reflected on the attributional dimensions of locus of causality, stability and globality; for categorization effects, both Chinese and American undergraduates' self-serving attributional bias were reflected on attributional difference between self's negative behavior and others', but Chinese undergraduates were embodied on the attributional dimensions of locus of causality, stability and globality while American undergraduates were reflected on the attributional dimensions of stability and globality. It also found Chinese undergraduates had more self-serving attributional bias than American undergraduates. This was reflected on the attributional dimensions of locus of causality, stability and controllability for outcome effects, and for categorization effects, locus of causality, stability and globality rating for self and others' negative behavior. All studies indicated that Chinese and American undergraduates' implicit theories had no significant effects on all their four attributional bias. These findings' potentially important implications were discussed and the further research was suggested.

大学生应激应付研究

In this study, we made research on coping with stress in undergraduate students. The whole work included two parts: (a) We developed the Coping Strategies Questionnaire and had it tested. Five kinds of coping strategies were found by factor analysis: Problem Solving, Passive Acceptance, Support Seeking, Emotion Regulation, and Unadaptation. The reliability and validity coefficients of the questionnaire was high. (b) We examined the relations among personality characteristics (Locus of control, Extraversion, Neuroticism), emotion state, cognitive appraisal (psychological pressure, controllability, resource of social support), and the specific coping processes in several specific stressful events. The results indicated that coping have some degree of consistency across different situations which suggested that there is a general coping tendency, and that this general coping tendency, in addition to the above considered variables, have different degree of effects on subjects' choice of specific coping strategies. Finally, theoretical model of the relationship was tested through path analysis.