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面向低成本变速应用交流电机转速控制IC显身手

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电子测试（新电子） 2006年第4期 23-30页

作者： dave wilson 飞思卡尔半导体

最新的 PWM 生成和控制技术已成功与一些预编程解决方案中的一流控制算法结合。以飞思卡尔MC3PHAC 为例,该解决方案旨在降低变速交流电机控制应用的一线开发成本,并加快产品上市进程。虽然无需编程但保留了设备的灵活性,用户可根据特定... 详细信息

最新的 PWM 生成和控制技术已成功与一些预编程解决方案中的一流控制算法结合。以飞思卡尔MC3PHAC 为例,该解决方案旨在降低变速交流电机控制应用的一线开发成本,并加快产品上市进程。虽然无需编程但保留了设备的灵活性,用户可根据特定应用进行定制设计。同时对设备的安全和故障处理功能也给予了特别关注,如"失效晶体(Dead-Crystal)"关闭、硬件故障停机和 DC 总线监视/保护等。

关键词：变速交流电机控制应用开发成本控制IC 电机转速控制算法控制技术定制设计 DC总线硬件故障

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青少年球员成材十大要素

网球天地 2004年第4期 54-55页

作者： dave wilson 张伟

任何人要想在网球运动中取得成功,仅仅依靠运动能力和训练是不行的。众多成功的球员身上还包括了许多其他的品质和行为因素。有研究表明,培养这些重要的品质要素,有利于促进年轻选手的学习,并能充分地挖掘他们内在的潜力和改善其竞技水... 详细信息

任何人要想在网球运动中取得成功,仅仅依靠运动能力和训练是不行的。众多成功的球员身上还包括了许多其他的品质和行为因素。有研究表明,培养这些重要的品质要素,有利于促进年轻选手的学习,并能充分地挖掘他们内在的潜力和改善其竞技水平。这十大要素都包括哪些呢?

关键词：少年选手网球运动教练员年轻选手球员心理素质网球比赛运动员比赛中健康的体魄

Mantle avalanches in a Venus-like stagnant lid planet

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Earth and Planetary Physics 2024年第5期8卷 686-702页

作者： Madeleine C.Kerr dave R.Stegman Institute of Geophysics and Planetary Physics Scripps Institution of Oceanography University of California

Stagnant lid planets are characterized by a globe-encircling, conducting lid that is thick and strong, which leads to reduced global surface heat flows. Consequently, the mantles of such planets can have warmer interiors than Earth, and interestingly, a pyrolitic mantle composition under warmer conditions is predicted to have a distinctly different mantle transition zone compared to the present-day Earth(Hirose, 2002; Stixrude and Lithgow-Bertelloni, 2011; Ichikawa et al., 2014; Dannberg et al, 2022). Instead of olivine primarily transforming into its higher-pressure polymorphs such as wadsleyite and then ringwoodite, at pressures corresponding to410 km and 520 km depth in Earth, respectively, it instead transforms into a mineral assemblage of wadsleyite, majorite, and ferropericlase(WMF), and then to majorite + ferropericlase(MF), before finally transforming into bridgmanite at pressures corresponding to 660 km depth in Earth(Stixrude and Lithgow-Bertelloni, 2011; Ichikawa et al., 2014). Convective motions in stagnant lid planets are dominated by small-scale instabilities(cold drips) forming within the mobile rheological sublayer under the rigid lid. Using ASPECT and a thermodynamic model of a pyrolitic mantle composition generated by HeFESTo, we show that under certain conditions, the small drips can pond atop the WMF-MF mineral phase transition. The barrier to convective flow arises from the WMF mineral phase assemblage having an effective negative thermal expansivity(Stixrude and Lithgow-Bertelloni, 2022). Although large-scale downwellings that typically occur within mobile lid planets are able to pass through the WMF zone without difficulty(Dannberg et al., 2022; Li RP et al.,2024), the smaller and less negatively buoyant nature of downwelling drips in stagnant lid planets are more susceptible to these effects,which leads to an ephemeral layering of the mantle. Our numerical models show that in stagnant lid planets with mantle potential temperatures that exceed

关键词： Venus mantle avalanches numerical modelling phase transitions

A Review on Dental Age Estimation in Children and Adolescents

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Journal of Forensic Science and Medicine 2024年第3期10卷 220-233页

作者： Ishita Singhal Aparna dave Manpreet Arora Radhika Rai Pulin Saluja Department of Oral Pathology and Microbiology and Forensic Odontology S.G.T.Dental CollegeHospital and Research InstituteGurugramHaryanaIndia

Children are seen as beings who exist from birth through puberty,while teenagers are regarded as existing from puberty until around the age of 20 *** a number of legal processes,including child labor,employment,the age of majority,rape,adoption,marriage eligibility,and situations where the birth certificate is unavailable,age estimation in children and adolescents is *** the wide range of methods available,dental age estimation techniques that take into account tooth maturation are thought to be the most reliable predictors of chronological age in *** is because genetic factors predominate and environmental factors,particularly between birth and age ten,tend to have little impact on tooth *** eruption of teeth holds greater significance in the deciduous dentition,where genetic factors predominantly govern the process,compared to the permanent ***,tooth calcification serves as a viable indicator for estimating dental age in both primary and permanent *** dental age estimation methods are based on age-related changes in teeth,such as tooth growth and development,changes that occur after teeth form,and biochemical ***,in this review article,we will explore the several methodologies used for dental age assessment in children and adolescents.

关键词： Adolescence age assessment children forensic odontology teeth

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英特尔需要执行转型计划而不是被人收购

商业周刊（中文版） 2024年第15期 14-16页

作者： dave Lee 逸思(译) 不详

有人说,如果硅谷有座拉什莫尔山,那么第一张被刻凿在石头上的脸应当是戈登·摩尔(Gordon Moore)。这位英特尔公司(Intel Corp.)联合创始人对集成电路上容纳半导体数量增长速度的著名论断,为美国在科技领域的领先地位奠定了基础。

关键词：增长速度集成电路第一张英特尔收购著名论断半导体

Changes in Soil Physicochemical Properties under Selected Climate-Smart Agricultural Practices in Central African Republic

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Open Journal of Soil Science 2024年第1期14卷 97-114页

作者： Julie Léancy Gougodo De Mon-Zoni Arnauld dave Bangane Konzoba Jane Akoth Omenda Mohammad Zaman Ephrem Kosh-Komba Plant and Fungal Biodiversity Laboratory Faculty of Sciences University of Bangui Central African Republic Central African Institute for Agricultural Research (ICRA) Bangui Central African Republic Laboratoiry of Geoscience Faculty of Sciences University of Bangui Bangui Central African Republic Departement of Water & Agricultural Resources Management University of Embu Embu Kenya International Atomic Energy Agency (IAEA) Vienna Austria Laboratory of Biological and Agronomical Sciences for Development Faculty of Sciences University of Bangui Bangui Central African Republic

Soil nutrient depletion as a result of continuous cultivation with insufficient external nutrient replenishment is a major challenge in sub-Saharan Africa (SSA). A trial using the organic and mineral fertilizer was established in the cassava cropping system of the Pissa and Damara areas to address the declining soil fertility. The study aimed to evaluate the effect of cow manure and mineral fertilizer in combination or sole application on soil physico-chemical properties and macronutrients. The experimental trial adopted a randomized complete block design (RCBD) replicated four times. The treatments comprised of;T1 (Control), T2 (Peasant practice), T3 (sole NPK), and T4 (Cow manure + NPK). The data on soil physicochemical analysis was subjected to a one-way analysis of variance in SAS 9.4 and the mean was separated by Tukey’s HSD test at p < 0.005. The soil pH values ranged from 4.20 to 4.91;and 4.53 to 5.28 in Pissa and Damara respectively. According to the treatments, a low pH value is observed in T3 (4.13) in the Pissa. Combined use of cow manure and the mineral fertilizer resulted in higher Mg K and N in the Pissa region and higher soil pH in Damara. The use of sole NPK (T3) gave a higher soil carbon and CN ratio. In the Pissa region the CEC, Cu, Fe, and Zn were higher in the treatments with mineral fertilizer compared to the control. Conclusively, the use of mineral fertilizer and cow manure can be used with optimum rates to improve soil physico-chemical properties on a sustainable basis.

关键词： Cow Manure Physicochemical Nutrients Agroecology Nutrient Management

The Use of 'In Process' Monitoring Equipment in Heat Treatment Today

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材料热处理学报 2004年第5期25卷 591-596页

作者： dave Plester Datapaq limited Cambridge CB4 OGU UK

This paper looks at how in-process temperature monitoring systems are being increasingly used in heat treatment applications such as surface hardening, annealing, normalizing, tempering etc. We look at the basic equipment required to successfully monitor from within a furnace and how developments such as RF transmission have enhanced the effectiveness of profiling trials to the point where on line adjustments to furnace conditions can be seen and analyzed in real time. We examine how continuous processes can benefit from this type of monitoring and also how routine operations such as furnace surveying in batch furnaces can benefit greatly from in-process monitoring. Advances in software are also considered, showing how packages are now designed to speed up the processing of data in day to day heat treatment operations.

关键词：热处理温度监测器射频传输剖面测量

IQR-based approach for DDoS detection and mitigation in SDN

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Defence Technology（防务技术） 2023年第7期25卷 76-87页

作者： Rochak Swami Mayank dave Virender Ranga Department of Computer Engineering National Institute of TechnologyKurukshetraIndia Department of Information Technology Delhi Technological UniversityDelhiIndia

Software-defined networking(SDN) is a trending networking paradigm that focuses on decoupling of the control logic from the data plane. This decoupling brings programmability and flexibility for the network management by introducing centralized infrastructure. The complete control logic resides in the controller, and thus it becomes the intellectual and most important entity of the SDN infrastructure. With these advantages, SDN faces several security issues in various SDN layers that may prevent the growth and global adoption of this groundbreaking technology. Control plane exhaustion and switch buffer overflow are examples of such security issues. Distributed denial-of-service(DDoS) attacks are one of the most severe attacks that aim to exhaust the controller’s CPU to discontinue the whole functioning of the SDN network. Hence, it is necessary to design a quick as well as accurate detection scheme to detect the attack traffic at an early stage. In this paper, we present a defense solution to detect and mitigate spoofed flooding DDoS attacks. The proposed defense solution is implemented in the SDN controller. The detection method is based on the idea of an statistical measure — Interquartile Range(IQR). For the mitigation purpose, the existing SDN-in-built capabilities are utilized. In this work, the experiments are performed considering the spoofed SYN flooding attack. The proposed solution is evaluated using different performance parameters, i.e., detection time, detection accuracy, packet_in messages, and CPU utilization. The experimental results reveal that the proposed defense solution detects and mitigates the attack effectively in different attack scenarios.

关键词： SDN DdoS IQR Controller CPU utilization Packet_in

Microstructural Characteristics and Mechanical Properties of Low-Alloy, Medium-Carbon Steels After Multiple Tempering

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Acta Metallurgica Sinica(English Letters) 2019年第1期32卷 74-88页

作者： Erfan Abbasi Quanshun Luo dave Owens Materials and Engineering Research Institute Sheffield Hallam University Tyzack Machine Knives Ltd

The microstructure and mechanical properties of NiCrMoV-and NiCrSi-alloyed medium-carbon steels were investigated after multiple tempering. After austenitising, the steels were hardened by oil quenching and subsequently double or triple tempered at temperatures from 250 to 500 °C. The samples were characterised using scanning electron microscopy and X-ray diffraction, while the mechanical properties were evaluated by Vickers hardness testing, V-notched Charpy impact testing and tensile testing. The results showed that the retained austenite was stable up to 400 °C and the applied multiple tempering below this temperature did not lead to a complete decomposition of retained austenite in both steels. It was also found that the microstructure, hardness and impact toughness varied mainly as a function of tempering temperature,regardless of the number of tempering stages. Moreover, the impact toughness of NiCrMoV steel was rather similar after single/triple tempering at different temperatures, while NiCrSi steel exhibited tempered martensite embrittlement after single/double tempering at 400 °C. The observed difference was mainly attributed to the effect of precipitation behaviour due to the effect of alloying additions in the studied steels.

关键词： Medium-carbon steels Multiple tempering Alloying addition Mechanical properties Retained austenite Precipitation behaviour