基于STM32单片机的大学生体能监测仪设计与实现

体能监控仪作为生命体征监测设备,对于辅助大学生完成体能训练有很大帮助;基于STM32单片机技术,设计开发集成了多种传感器的一种大学生体能监测装备,它能够有效的检测包括心率检测、人体的步数、运动圈速、消耗卡路里等信息;该设计采用了STM32作为主控芯片,采用模块化的设计思路;在系统硬件设计方面,设计了包括STM32控制系统、心率获取电路、三轴传感器电路、显示电路以及按键电路等;同时将软件模块拆分成了初始化子程序、心率获取子程序,步数获取子程序,显示子程序等;Proteus仿真结果显示,使用STM32单片机技术设计的体能监测系统,能够运行稳定,测量心率范围60次/min~180次/min,可在心率异常时报警,同时检测步数的准确率达98%,满足体能监测任务需要,实验结果符合预期;为STM32单片机在体育运动研究信息化中应用提供参考。     

基于STM32的餐桌隔间装置控制系统的设计

为了解决中小型餐厅餐桌有空余位置而顾客不想拼桌并离开的问题,设计出一种基于手机APP和下位机STM32的餐桌隔间装置。该装置可实现将餐桌划分成四个至多个独立空间供单独客人使用,结合上下位机的工作模式,能实现餐桌分隔和不分隔的功能。系统包含液晶显示屏,方便顾客点选菜品,提高餐厅服务人员的工作效率。从控制系统的实现方法角度介绍该系统。实验表明,新设计具有良好的稳定性和可靠性,有效地提高了中小型餐厅餐桌座位的利用率。     

The status of and opportunities for utility-scale battery storage in Australia: A regulatory and market perspective

Australia's electricity market is rapidly adding renewable energy generation. Utility-scale batteries could have a major role in facilitating these transitions; however, their deployment is still largely state-subsidized. We summarize the current and future roles for batteries from a legal-economic perspective in the context of Australia's electricity market framework. We find that the future of batteries in Australia is not only a function of the large-scale deployment of renewables, their cost development and the comparative future cost of competing gas turbines but also of national electricity market and state policy reforms focusing on reliability.     

扫描隧道显微镜钨针尖的制备与表征

采用直流电化学刻蚀方法制备扫描隧道显微镜钨针尖,研究了电化学刻蚀过程中NaOH溶液浓度、钨丝浸入长度和刻蚀电压对针尖形貌的影响。通过扫描电子显微镜(SEM)测量针尖曲率半径和针尖纵横比值,以表征针尖的尺寸和形状;通过能谱仪(EDS)分析针尖表面成分,以表征表面清洁度;通过场发射显微镜(FEM)得到Fowler-Nordheim (F-N)曲线来检测针尖发射性能。实验结果表明,当溶液浓度为2 mol/L、钨丝浸入长度为4 mm、刻蚀电压为3 V时,可以得到曲率半径约为100 nm、纵横比值为13的针尖,且表面无钨的氧化层。FEM结果显示当对针尖施加500 V的负偏压时,针尖可以稳定发射50 nA量级的电流,且针尖性能具有良好的一致性。     

继电保护中多路模拟量采集系统的设计

介绍了一种基于高性能浮点DSP芯片TMS320C32、CPLD芯片XC95288和A/D采样芯片AD976组成的多路采集系统的工作原理以及设计方法。通过对第一路施加特殊的电压量,在CCS开发环境下读取采样缓冲区的值,并利用Matlab对采样数据进行了全波傅氏变换。此外,该系统已在继电保护中得到广泛应用,实践表明,该系统能较好地解决多路模拟量的采集,并确保了采样数据的安全可靠性。     

Robust skin detection in real-world images

Human skin detection in images is desirable in many practical applications, e.g., human–computer interaction and adult-content filtering. However, existing methods are mainly suffer from confusing backgrounds in real-world images. In this paper, we try to address this issue by exploring and combining several human skin properties, i.e. color property, texture property and region property. First, images are divided into superpixels, and robust skin seeds and background seeds are acquired through color property and texture property of skin. Then we combining color, region and texture properties of skin by proposing a novel skin color and texture based graph cuts (SCTGC) to acquire the final skin detection results. Comprehensive and comparative experiments show that the proposed method achieves promising performance and outperforms many state-of-the-art methods over publicly available challenging datasets with a great part of hard images.     

An experimental investigation of refrigerant mixture R32/R290 as drop-in replacement for HFC410A in household air conditioners

In the present paper, the refrigerant mixture R32/R290 (68%/32% by weight) is investigated as the drop-in replacement for R410A in household air conditioners. The GWP of it is only 22% of that of R410A. Theoretical and experimental investigations are conducted on the performance of the air conditioners working with both R32/R290 and R410A. Experimental results show that the refrigerant charge amount of R32/R290 is reduced by 30.0%–35.0%; the cooling and heating capacities are increased by 14.0%–23.7%. For further reducing charge amount and flammability, the micro-channel heat exchanger (condenser) is employed to replace the finned tube one. Compared with the R32/R290 system using finned tube heat exchanger, the R32/R290 charge amount and the power consumption are reduced by 34.1% and 0.4%, respectively; the cooling capacity and the COP are increased by 6.4% and 6.8%, respectively.     

水中SiO3^2-对红茶茶汤滋味品质的影响

通过分析SiO3^2-与主要味感物间的滋味互作效应,探究其影响茶汤滋味品质的内在机制。研究表明,随着SiO3^2-质量浓度的增加,茶汤甜味上升,鲜味、涩味、苦味及综合滋味品质下降;茶汤中儿茶素、茶多酚、氨基酸、表没食子儿茶素没食子酸酯(EGCG)含量和Ca^2+、K^+、Mg^2+等离子浸出量下降是SiO3^2-导致茶汤滋味品质下降的原因。进一步研究发现,SiO3^2-可有效增强谷氨酸钠溶液的鲜味和蔗糖溶液的甜味,显著减弱咖啡碱溶液的苦味和EGCG溶液的苦涩味,具有明显的滋味互作效应。建议日常冲泡红茶应选用含有适量SiO3^2-(<48 mg/L)的水。     

Synthesis and color tuning of titanium oxide inorganic pigment by phase control and mixed-anion co-doping

B and N co-doped anatase, rutile, and brookite TiO₂ (abbreviated as BN-Ana, BN-Rut, and BN-Bro) were successfully synthesized. The apparent color of as-obtain BN-Ana, BN-Rut and BN-Bro was red, cyan and yellow-green, respectively. The mechanisms of various coloring were concluded as the different band gap configurations and the formation of covalent B-N bonding. The nitridation time expressed less effect on changing the color. On the contrary, nitridation temperature enabled the distinct color changes by altering the brightness. Lower temperature, fewer doping concentration, and brighter apparent color, vice versa. Through tuning the brightness, a gradient of yellow-orange-red was achieved in the case of BN-Ana, as well the transitions of grey-to-cyan and white-to-pale-yellow were achieved in BN-Rut and BN-Bro, respectively. This research proposed a method for the synthesis of color-full titania pigment without the addition of other toxic transition metal elements.     

粒径对庚烷液雾爆炸场影响的数值模拟

为了研究液雾索特直径(D_(32))对爆炸参数的影响,以庚烷为对象,控制液雾总浓度不变(80 g·m~(-3)),改变液雾粒径,数值模拟了爆炸容器内庚烷(C_7H_(16))液雾粒径对爆炸参数的影响。结果表明:庚烷液雾场索特直径D_(32)为0~18.1μm时,最大爆炸压力p_(max)随D_(32)增加逐渐减小,最大值为1.01 MPa,最小值为0.9015 MPa。最大爆炸压力上升速率随D_(32)增大整体呈下降趋势,在0处达到最大值0.37571 MPa·ms~(-1),在18.1μm处达到最小值0.18439 MPa·ms~(-1),但在6.81~12μm发生反向突变,在10.1μm处达到极大值0.34217 MPa·ms~(-1),随后恢复下降趋势。液雾的径向火焰传播速度在径向距离15 cm附近突然增加,在16 cm之后剧烈下降。最大火焰速度随液雾场D_(32)不同而变化,D_(32)=10.1,12.9,18.1,6.81,0μm条件下液雾场的最大火焰速度依次降低,最大值为5.714 m·s~(-1),其后依次为1.737,1.36,1.34,1.27 m·s~(-1)。