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关键词： STC89C51单片机   助力自行车   测试传感器   环保  

摘要： 随着城市化进程的加速和环保意识的提高,电动车已经成为城市出行的主要交通工具之一。然而,传统的电动车助力系统只能提供固定的助力程度,无法根据骑行者的力量大小进行自适应调节,导致骑行的舒适性和效率较低。本文介绍了一种基于力矩传感器的助力系统,该系统可以根据骑行者的力量大小自动调节电动车的助力程度,提高骑行的舒适性和效率。系统采用力矩传感器作为输入设备,通过AD转换器将传感器输出的模拟信号转换为数字信号,然后通过单片机进行处理,控制电机的助力程度。系统还配备了LCD显示屏,用于显示当前速度、助力程度和电池电量等信息。通过实验验证,系统能够正常工作,实现了预期的功能。该系统具有自适应调节、舒适性和效率高等优点,可以为电动车助力系统的设计和开发提供参考。

关键词： 相控阵   全聚焦   全矩阵  

摘要： 全聚焦方法作为新兴的超声后处理成像技术具有成像分辨力高、算法灵活等优点。近年来,全聚焦技术在中国无损检测领域迅速发展,全聚焦超声检测设备性能取决于仪器软件全聚焦成像的算法。为更好地测试全聚焦超声检测性能,介绍了全聚焦相控阵超声检测的测试方法,并提出了一种适用于全聚焦技术的测试试块,为全聚焦技术的开发和应用提供参考。

关键词： 双轴稳定光纤惯导系统   捷联惯导系统   惯性平台系统  

摘要： 随着光纤陀螺的快速发展,光纤陀螺捷联惯导系统被广泛应用于各类武器系统。针对未来装备发展对惯导小型化、轻质化、低成本、高动态环境适应性等要求,提出了一种双轴稳定光纤惯导系统。该惯导系统吸收了平台式、捷联式、旋转式惯导系统的各自优点,将惯性平台隔离载体角运动、捷联导航解算与旋转调制抑制误差效应三者集于一体,提升纯惯性动态导航精度的同时,可做到相同惯性仪表条件下体积、质量更小。为验证该惯导系统的可行性,利用现有光纤陀螺惯性平台,通过“台体轴及内框轴双轴稳定+外框架单轴电锁”方式改造成双轴稳定光纤惯导,并进行了随机振动导航试验考核。试验结果表明,该惯导系统具备较高的动态导航精度。

关键词： 数据引流   异构传感器网络   能量空洞   防护算法   节点部署优化  

摘要： 异构传感器网络在工作时,靠近传感器基站位置的节点会由于接收转发次数较多而出现能量空洞现象。为有效对此现象实施防护,保障网络安全运行,提出数据引流下异构传感器网络能量空洞防护算法。构建网络节点部署模型,对传感器网络节点实施节点优化部署;计算网络节点能耗对网络实施能量均衡控制,获取异构传感器网络节点的簇内传输跳数;结合获取的节点簇内跳数以及能量均衡结果开展节点接收数据的的引流分配,平衡传感器网络层内节点能量消耗,实现传感器网络的能量空洞防护。实验结果表明,使用上述方法开展传感器网络能量空洞防护时,数据转发接收能耗较低,防护方法性能高,防护效果好。

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

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.

关键词： CCD   E-glass   Climate-resilient   Sustainability  

摘要： The objective of this investigation is to evaluate the durability of dune sand mortar containing display e-glass waste (DEGW) in severe Saharan environments, chemical attacks, or other factors that can cause cementitious materials to deteriorate at long- term. The aim is to use DEGW powder as a partial replacement for dune sand in various mortar mixtures and assess the performance of hardened mortar in terms of ultrasonic pulse velocity, dynamic elasticity modulus, compressive strength, and flexural strength and sportivity. The study also examines the influence of the curing period and different climatic conditions in curing environments, such as those in Algeria's Sahara region. The Response Surface Methodology (RSM) was used to adjust the e-waste glassy mortar, with the statistical tool Central Composite Design (CCD) approach. The hydration of cement compounds was monitored using differential thermal analysis (DTA), thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC), and X-ray diffraction (XRD). The DEGW was replaced in 5% increments from 0% to 20%. The results showed that the glassy dune sand mortar exhibited the highest properties at 20% incorporation after 365 days of severe climatic conditions. The feasibility of the proposed quadratic model was recommended for the five responses by RSM, in which the coefficient of determination (R2) ranges from 0.93 to 0.97, showing the model's high significance. For structural display e-glassy dune sand mortar, display glass E-waste can replace 20% of dune sand, which improves all durability and environmental sustainability. Furthermore, the DSC, TGA / DTA results and XRD analysis showed that the < 0.08 mm class exhibited good pozzolanic behaviour, and the specimens significantly improved as curing periods increased.