无线电能传输系统谐振线圈优化设计

以磁耦合谐振式无线电能传输系统两线圈等效电路模型为例,详细分析了谐振线圈的线圈半径、导线半径和线圈匝数等参数对谐振线圈电感和空载时的品质因数的影响;在电源频率为13.56MHz时,得出谐振线圈的优化参数如下:电感值为2.634×10-5 H,分布电容值为5.229×10-6μF,线圈半径为50mm,导线半径为1.05mm,线圈匝数为10匝。该优化结果对磁耦合谐振式无线电能传输系统的研究具有一定的参考价值。     

温度流量复合传感器

温度流量复合传感器用来同时测量水、酒精和煤油等液体介质的温度和流量。温度敏感元件采用Pt10 0 0 ,它的温度系数是 385 0× 10 -6/℃。流量采用旋翼式涡轮流量传感器测量。叶轮上的磁钢随着流体介质的流动而做圆周运动 ,磁钢上方的霍尔元件在磁钢通过它时输出电脉冲信号 ,频率电压转换器将正比于流量的频率信号转变成电压信号。温度和流量传感器的测量范围和准确度分别为 0～ 10 0℃、0～ 10L/min、± 0 .5℃、± 2 %FS。     

选择电子仪器应该注意的几个问题

人们在选型时 ,首先注意仪器的精度 ,这是无可非议的。但是 ,仪器的精度 0 .0 5级或允许误差± 0 .0 5%只有在参考环境温度 (国内为 2 0℃± 2℃、国外为 2 3℃± 2℃ )范围内才能保证。偏离此温度 Δt时 ,就要加甚大的温漂误差。温漂误差 =温度系数× Δt1仪器温度系数的重要性绝对不可忽视仪器不一定就在恒温室内使用 ,特别是便携式仪器 ,在现场使用时温度偏离允许值可达± 2 0℃左右。为避免仪器引入很大的温漂误差 ,就得特别注意仪器的温度系数 ,否则就会大大吃亏 !在仪器选型时 ,千万不能只看其基本误差 ,一定要再看看它的温度系数。通…     

热膜风速计温度校正研究

为提高热膜风速计在非恒温流场状况下的测量精度,提出了一种温度自动校正方案。通过对热膜探头的温度特性分析,提出采用铂电阻作为热膜风速计的温度补偿元件。经温度校正后,热膜风速计零点温度漂移可以达到4.8×10-2%FS/℃,灵敏度温度漂移可以达到-1.0×10-2%FS/℃。试验结果表明:利用铂电阻对热膜风速计进行温度自动校正取得了较为理想的效果。     

基于SnO_2传感器对液化石油气的动态检测

采用SnO2 传感器对家用液化石油气进行动态检测。介绍了整套实验装置及具体的实验操作过程;对实验结果进行分析,表明动态检测方法可以明显地提高SnO2 传感器的选择性,检测下限为10-7 mol/L,检测上限为 5×10-6 mol/L,检测准确度为 0. 2×10-7 mol/L。     

进料温度和回流比对多元精馏塔能耗的影响——计算机设计与模拟

在 Burroughs—6935大型电子计算机上,对苯—甲苯—乙苯—苯乙烯四元混合物的常压精馏,进行了精馏塔的设计与操作模拟,并在进料温度 T_F=340K～398K(包括冷液,沸点,汽液混合和饱和蒸汽四种进料热状态),回流比 R=1.5～3.5的变化范围内,考察了进料温度和回流比对多元精馏塔再沸釜能耗 q_r 和总能耗 Q_R 的影响。计算结果指出,若保持 R 恒定,进料热状态 Q>1时,与△T_F=10℃相对应的△q_r 随料温的变化幅度约为2×10_3～5×10_3KJ/kg-mol(料液)·hr;Q<1时,约为8×10~3～4×10~4KJ/Kg-mol(料液)·hr。若保持 T_F 恒定,则 R 的增加将使 q_r 也随之增加,同时分离质量也得到提高。精馏塔总能耗 Q_R 随 T_F 和 R 增加而增加。对 Q>1的进料热状态,计算机回归得到:q_r=1.996×10~7×T_F~(-9.464×10~(-5))×R~0.668[KJ/Kg-mol(料液)·hr]     

双冠醚钠离子选择电极的研制

本文用新合成的2—氯—4,6—双(4′—亚氨基苯并—12—冠—4)三嗪(以下简称双冠醚)作电活性物质,制成钠离子选择电极。其电极性能、线性范围:10°～5×10~(-5)M,斜率为55±1mv,对Li~+、NH_4~+、Mg~(2+)、Zn~(2+)和Ca~(2+)的选择系数分别为7.7×10~(-2)、1.1×10~(-2)、8.4×10~(-4)、4.0×10~(-4)和4.6×10~(-4)。     

新疆原油馏分油表面张力的实验测定与预测方法

实测新疆原油 18个宽、窄馏分油不同温度下的表面张力 10 2组 ,在所得数据的基础上 ,采用逐步回归方法处理实验数据 ,得到计算石油馏分表面张力的计算式 2个 ,其平均绝对偏差分别为 0 41× 10 -3N/m和 0 32×10 -3N/m ,,平均相对偏差分别为 1 82 %和 1 39%。考察两种常用计算方法对新疆油表面张力计算的适用性 ,其平均相对偏差分别为 15 6 %和 2 4 4%。通过对这两种方法进行修正 ,平均相对偏差分别降到 1 2 9%和 1 97% ,其准确性与所得关联式相当     

戊二醛偶联组氨酸修饰金电极测定铜离子的研究

本文主要研究了一种基于戊二醛偶联组氨酸修饰金电极的方法 ,并以该修饰电极为工作电极利用方波伏安法建立了一种检测痕量铜离子的新方法。在铜溶液中搅拌富集 ,铜离子与修饰电极表面的组氨酸形成配合物吸附在电极表面 ,在磷酸缓冲液 (pH 6 8)中 ,该配合物具有良好的电化学响应。在对不同浓度的铜离子进行检测时发现在 1× 10 - 1 2 ～ 1 8× 10 - 1 1 mol/L和 5× 10 - 7～ 2 1× 10 - 5mol/L之间方波伏安还原峰电流与铜离子浓度呈现良好的线性关系 ,其最低检测限可达 0 5× 10 - 1 2 mol/L ,并对可能的检测机理进行了探讨     

SnO_2-ZnO复合膜特性研究

用真空蒸发的方法,在1.33×10-3Pa的真空中,蒸发SnO2,ZnO获得超微粒结构的SnO2-ZnO复合膜。当复合膜中ZnO质量分数为20%时,SnO2-ZnO复合膜对乙醇气体的灵敏度为40,膜的方电阻值也较低,为0.01×103Ω/□。复合膜经热处理后,其电学性能也得到改善,当温度t=600℃时,ZnO质量分数为20%的SnO2-ZnO复合膜热处理后,其膜对乙醇气体有较高的选择性,灵敏度为60。当t=400℃时,对掺有Sb2O5质量分数为450×10-6,ZnO质量分数为20%的SnO2-ZnO复合膜进行热处理,其方电阻仅为0.003×103Ω/□,具有优良的导电性能。     

用于低温环境的铂电阻温度微传感器

目前,铂电阻温度传感器主要应用于73 K(-200℃)以上环境的温度检测。设计了可用于10 K(-263℃)～200 K(-73℃)低温区的铂电阻温度微传感器。铂电阻温度微传感器采用对称的折回型结构,这种结构有效地降低了交流感抗的影响。传感器的敏感薄膜是一层采用磁控直流溅射沉积厚度为200 nm的铂薄膜。采用QD PPMS仪器测试传感器的电阻与温度的变化关系,得出传感器的电阻温度系数(TCR):研制的温度传感器的电阻温度系数在温度高于30K(-243℃)时可达到9980×10-6/K,同时在低于30K(-243℃)的深低温区域TCR也可达到3730×10-6/K。     

高选择性常温NH_3传感器

采用MEMS技术,如KOH腐蚀、光刻、溅射金属等技术,在硅片、玻璃等材料上制得平面式微传感器管芯,此结构具有微型化、低功耗、一致性好、适宜大批量生产的优点。敏感材料的采用不同于传统无机物,而是以苯胺为原料,合成高分子聚合物———聚苯胺,此敏感材料不需要加热源,其电阻在室温下与NH3浓度成一定函数关系,可以测得空气中较低含量的NH3。聚苯胺的另一个显著优点是高选择性,实验表明,高达1000×10-6(气体体积分数)的H2,CH4,CO,C4H10,C2H5OH的灵敏度远低于50×10-6(NH3气体体积分数)的灵敏度。     

The effect of monomolecular surface films on the microwave brightness temperature of the sea surface

Abstract

Airborne microwave radiometer measurements at 1·43 and 2·65 GHz over a sea surface covered with a monomolecular oleyl alcohol surface film and over adjacent slick sea surfaces are presented. The measurements show that at 2·65 GHz the brightness temperature T _B is not affected by the slick, while at 1·43 GHz it drops from 93 K to a minimum value of almost O K. This implies that at 1·43 GHz the emissivity of the slick-covered sea surface is extremely small, similar to a metallic layer, and that this resonant-type phenomenon is confined to a narrow frequency band of width δ?/ ?<0·6.

The theoretical implications of these experimental findings are discussed in the framework of the Debye relaxation theory of polar liquids. It is conjectured that a thin layer of water molecules polarized by the surface film gives rise to an anomalous dispersion, which causes the large decrease in brightness temperature at 1·43 GHz.

The modulus of the relative dielectric constant ε? is estimated to be ≥ 5·2 × 10^?4 and the thickness of the emitting layer ≤1·9 × 10^?4 m for 1·43 GHz. Furthermore, the film-induced surface activation energy is calculated to be 9·18 × 10^?21 J. These values seem reasonable in the light of the theories on the physicochemical structure of surface layers.     

石英晶体温度传感器的应用

介绍了石英晶体温度传感器的主要性能指标。分析了石英温度传感器非线性、频率不确定度、过热效应等因素对温度测量的影响。成功地研制了采用Y +5°切的石英晶体温度传感器的温度计 ,其温度分辨力达到 10 -4 ℃。     

The effects of variation in body temperature on the preferred water temperature and flow rate during showering

The purpose of this study was to investigate the effects of body temperature variations on subjects' preferred water temperature and flow rate during showers. Nine healthy women students took a shower before and after physical exercise (running on a treadmill for 30 min) and water immersion (immersing in the water of 25^°C temperature for 30?min). During each shower, the subject was instructed to adjust both the water temperature and flow rate of a shower to suit their comfort. Rectal temperature and skin temperatures of the subjects, water temperature, and flow rate of the shower were measured during the experiments. The means of preferred water temperature during showers were 40·2^°C and 43·8^°C before and after water immersion respectively, which were significantly different. On the other hand, there was little difference in the preferred water temperature between before and after the treadmill exercise. There were no significant differences in the flow rates between before and after both water immersion and the treadmill exercise. A significant negative relationship was observed between the mean body temperature (T¯_b) and the preferred water temperature during showers (r=?0·439). On the other hand, no significant relationship was found between T¯_b and the preferred flow rate. Moreover, a significant negative relationship was observed between the preferred water temperature and the flow rate during showers (r=?0·528).     

分布式光纤测温系统及高速数据采集与处理

分布式光纤测温系统是一种用于实时测量空间温度场分布的传感器系统。介绍了一种以数字信号处理器(DSP)为核心,以并行高速流水线式A/D转换器、先入先出队列芯片(FIFO)、可编程逻辑器件(CPLD)为主体的分布式光纤测温系统。其数据采集速率每秒可达10×107次,空间分辨力达1m,温度分辨力为1℃,并能直接在主机中解调出温度数据。     

气体流速流向传感器及其温度补偿的研究

设计了一种内燃机用气体流速、流向传感器,阐述了传感器的工作原理;介绍了应用单片机对传感器输出信号进行线性化和温度补偿处理的方法。试验结果表明:该传感器在-20~100℃温度范围内,温度稳定性高,零点温度漂移为4.0×10-3%FS/℃,准确度可达到±1.0%FS,性能指标达到了设计要求。     

高准确度宽温石英晶振热敏网络温度补偿

论述了热敏网络进行石英晶体温度补偿的基本方法,其中包括热敏电阻器的测量、非线性回归以及匹配算法,还介绍了补偿电路以及5种热敏网络的设计,并通过大量试验曲线讨论了在较宽温度范围内,当补偿准确度达到或超过1×10-6时应该考虑的各种因素。     

Effects of color temperature and luminance of LEDs on color judgments involving various printing materials

This study investigated errors in color judgment related to stimuli (cyan vs. magenta vs. yellow) printed on various materials (coated paper vs. cotton vs. polyester fiber) and occurring in a range of visual environments (color temperature × luminance: 4000 K × 1500 lx vs. 4000 K × 750 lx vs. 2700 K × 1500 lx vs. 2700 K × 750 lx) under illuminated light‐emitting diodes. Participants included 16 female and 14 male Taiwanese college students [age range, 20–26 years (M = 21.92, SD = 2.13)]. Subjects were instructed to perform a series of comparative judgments in which they carefully observed a standard stimulus color under illuminated LEDs and judged which of five simultaneously presented colors under illuminant D65 was the most similar to the standard color. Data analysis revealed that the effect of visual environment on accuracy of color judgments against the standard was significant. Additionally, the accuracy of color judgments against the standard was significantly better for polyester printing material than it was for coated paper. The color of the standard also significantly affected color judgment accuracy: cyan yielded significantly worse accuracy rates than did magenta or yellow. These results have implications for lighting design and interior design.