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关键词： 石墨烯  

ISBN: (纸本)9787115619884

摘要： 本书介绍了石墨烯的基本特性(力学、热学、光学和电学性能)及石墨烯膜与基底间界面吸附力学行为；其次，结合光纤干涉型传感技术优势，阐述了新型石墨烯膜光纤Fabry-Perot(F-P)干涉型声压、温度、湿度传感器以及谐振式压力传感器的工作原理、敏感特性、制备工艺和性能测试，以及谐振式加速度传感器的结构和测试等内容；分析了现阶段该技术存在的问题，总结了未来发展趋势。

关键词： 无线电通信   互联网络   智能技术  

ISBN: (纸本)9787121474262

摘要： 本书共7章，主要介绍无线传感器网络的基本概念与体系结构、无线传感器网络支撑技术、无线传感器网络安全技术、物联网无线通信技术、物联网接入与互联技术；进而以车联网通信技术为典型对象，分析并讨论物联网与车辆交通领域的网络化、智能化融合技术。

关键词： Diamond   Field effect transistor   Radiation   Imaging device   Multigate FET  

摘要： The escalating demand for imaging devices operating in harsh environments has prompted investigations into the applicability of diamond, often called the ultimate semiconductor material. A multigate field effect transistor (FET) is a crucial component of Charge-Coupled Devices (CCDs) for imaging devices, and we developed it on a hydrogen-terminated diamond (H-diamond) for the first time. This milestone not only showcased the potential realization of diamond CCDs but also provided key insights for future research. Specifically, this paper explores the electrical and structural needs to achieve signal transmission throughout the fabricated diamond multigate FET.

关键词： GPT   LLM   clinical densitometry   CCD  

摘要： Background: Artificial intelligence (AI) large language models (LLMs) such as ChatGPT have demonstrated the ability to pass standardized exams. These models are not trained for a specific task, but instead trained to predict sequences of text from large corpora of documents sourced from the internet. It has been shown that even models trained on this general task can pass exams in a variety of domain-specific fields, including the United States Medical Licensing Examination. We asked if large language models would perform as well on a much narrower subdomain tests designed for medical specialists. Furthermore, we wanted to better understand how progressive generations of GPT (generative pre-trained transformer) models may be evolving in the completeness and sophistication of their responses even while generational training remains general. In this study, we evaluated the performance of two versions of GPT (GPT 3 and 4) on their ability to pass the certification exam given to physicians to work as osteoporosis specialists and become a certified clinical densitometrists. The CCD exam has a possible score range of 150 to 400. To pass, you need a score of 300. Methods: A 100 -question multiple-choice practice exam was obtained from a 3rd party exam preparation website that mimics the accredited certification tests given by the ISCD (International Society for Clinical Densitometry). The exam was administered to two versions of GPT, the free version (GPT Playground) and ChatGPT+, which are based on GPT-3 and GPT-4, respectively (OpenAI, San Francisco, CA). The systems were prompted with the exam questions verbatim. If the response was purely textual and did not specify which of the multiple-choice answers to select, the authors matched the text to the closest answer. Each exam was graded and an estimated ISCD score was provided from the exam website. In addition, each response was evaluated by a rheumatologist CCD and ranked for accuracy using a 5-level scale. The two GPT

关键词： Biodiesel   Waste chicken fat   Experimental design   Diesel Engine   Nano-additive  

摘要： The present study aimed at the fabrication of an efficient nanocatalyst utilizing cerium doped on hematite (Cedoped Fe2O3) as a highly reactive catalyst in biodiesel generation from waste chicken fat (WCF) under ultrasonication and also as nano -additive to improve diesel engine features. The surface features of Fe2O3 and Ce@Fe2O3 nanoparticles were investigated utilizing several analyses. The characterization outcomes demonstrated that the Ce element was successfully incorporated into the Fe2O3 structure. RSM-assisted experimental design was utilized to optimize effective parameters on biodiesel efficiency. According to the CCD results, the maximum biodiesel yield employing Fe2O3 and Ce-doped Fe2O3 nanocatalysts was 91.57% and 95.38%, respectively, which were obtained after 30 min of ultrasonic irradiation time. Also, various proportions of petrodiesel and biodiesel as well as adding Ce@Fe2O3 nanoparticles to the fuel blend at different torques (20-100%) were tested on diesel engine parameters. The outcomes revealed that adding biodiesel to petrodiesel diminished CO (10.02%) and UHC (6.34%). Further, increasing biodiesel content in the fuel composition enhanced BSFC (8.29%) and EGT (14.17%) parameters and declined BTE (13.37%). Besides, increasing the percentage of torque enhanced EGT and BTE and reduced BSFC. Also, adding Ce@Fe2O3 nanoparticles to biodiesel/diesel blends reduced CO, NOx, and UHC concentrations, and enhanced BTE and BSFC values. Kinetic and thermodynamic analyses reveal that the transesterification reaction is first -order and endothermic. Furthermore, the activation energy for biodiesel generation using Fe2O3 and Ce-doped Fe2O3 nanocatalysts were attained at 46.61 and 46.58 kJ/mol, respectively, which are considerable amounts. Besides, the reusability investigation showed that Ce-doped Fe2O3 nanoparticles have high stability, so that after the 7th cycle, the biodiesel yield was 87.26% (only a 7.5% decrease in efficiency). Generally, owing to uniqu

关键词： AC/TiO2 nanoparticle   Central composite design   Filtration characteristics   PAC-L   Rheological properties  

摘要： Limited studies are performed in the petroleum sector on titanium dioxide (TiO2) nanoparticles and its crystal form. Moreover, no study is reported up till now that studied the combination of carbonaceous material and TiO2. In the current work, the rheological and filtration characteristics of water-based mud was investigated after the addition of polyanionic cellulose grade-L and AC/TiO2 nanoparticles. To verify the impact of these two particles on the rheological and filtration behavior, central composite design was implemented, which further validates the experimental results. According to the research, concentration of particles was a significant parameter in maintaining rheological properties and minimizing the fluid loss volume. The AC/TiO2 nanoparticle was mainly responsible for keeping the plastic viscosity, yield point and gel strength within API standards. On the other hand, when the concentration of PAC-L goes beyond the critical concentration, the PV of the mud sample goes beyond API protocols;however, yield point and gel strength were not affected. The effect of these particles on API low-pressure low-temperature filtrate press test was also examined. The fluid which shows the maximum fluid loss volume and greater mud cake thickness was Sample 4. This sample had the least concentration of polymer and nanoparticles. The performance of PAC-L in filtration control yields a negative response. This polymer was unable to control the fluid loss effectively. The presence of K + ions in the base mud was responsible for this lower performance, as it dehydrates the polymeric material. On the other hand, the AC/TiO2 nanoparticle was mainly responsible for controlling the fluid loss volume and minimizing the mud cake thickness. Furthermore, the addition of AC/TiO2 nanoparticles in water-based mud system was effective in mitigating the shale swelling behavior. The concentration of this particle demonstrated strong negative correlation. This particle was responsible f

关键词： 光导纤维  

ISBN: (纸本)9787118131215

摘要： 本书论述了光子晶体光纤陀螺的原理、光子晶体光纤特性及在陀螺中的误差机理、光纤设计与制备、光子晶体光纤熔接、环圈绕制、直接耦合技术，同时介绍了光子晶体光纤陀螺光源、调制解调、结构设计、数字仿真分析，以及惯性导航应用技术等。

关键词： Galaxy: general   globular clusters: individual: NGC 5897   techniques: photometric  

摘要： We report CCD photometric observations of the globular cluster NGC 5897, in the Johnson system filters B, V, R, and I. With the values for these magnitudes we obtain various colour indices and produce several colour-magnitude diagrams. We present eight colour-magnitude diagramas: V vs B - V, B vs B - V, V vs V - I, I vs V - I, R vs R - I, I vs R - I, V vs V - R, and R vs V - R. In all of these diagrams we can clearly see the giant branch, the horizontal branch and the beginning of the main sequence. To the left of the main sequence turn-off point we detect a somewhat large number of blue straggler stars. We determine the mean value of the visual magnitude of the HB as 16.60 +/- 0.46. This value is fainter than the value found by other authors.

关键词： 动车  

ISBN: (纸本)9787113310479

摘要： 本书共分为四章: 包括TEDS构成、功能与运用管理, 动车组转向架TEDS实拍图及结构组成, 动车组TEDS检查内容, 质惫标准及故隐案例。

摘要： 高功率光纤激光技术的发展日新月异,2004年第一台单模千瓦级光纤激光器诞生,之后我国多家单位相继实现了高功率光纤激光千瓦级功率的输出.随着光纤材料器件等制备工艺的革新和高亮度泵浦、非线性效应抑制等关键技术的突破,我国高功率光纤激光技术得到了持续高速发展,为制造、能源和前沿科学等领域及航空航天、轨道交通、汽车、材料处理等行业带来了全新的方法和工具,在社会进步和经济发展中发挥了巨大的作用.