共查询到20条相似文献，搜索用时 328 毫秒
1.
学习温度计以后，程实同学的课堂作业得了全优；唯独两道课外补充题做得一对一错，很不如意．他解析两道补充题的情况如下：１．将一支温度计放在冰水混合物中它显示０℃，放在一个大气压下的沸水中它显示出１０８℃．当用这支温度计测量一杯烫水的温度为８１℃时，试问这杯烫水的温度真有８１℃吗？解析这杯烫水的真实温度是：ｔ＝（１００／１０８）×８１=７５（℃）．答这杯烫水的温度没有８１℃，而是７５℃．２．一支不标准的温度计在０℃时显示零下５℃，而在８０℃时显示８５℃．用它测量一杯热水的温度为４９℃，试求这杯热水的实… 相似文献
2.
设计了一款基于单片机的十二路温度采集系统,每路温度测量范围为-55℃—125℃。系统主要包括单片机模块、十二路温度传感器模块、按键模块、LCD液晶显示模块及报警模块。十二路温度传感器将检测到的温度信号传送给单片机,单片机控制LCD显示屏依次循环显示每路温度值。按键模块可设定检测的温度范围,一旦超出范围区间,报警模块产生声光报警。仿真实验数据统计显示,本系统所检测的温度误差小于1%,验证了本系统具有较高的精度。 相似文献
3.
田宏乐 《中学物理教学参考》1999,(11)
在近三年的全国初中物理知识竞赛的复赛试题中有两年出现了有关“温度计”的计算题,那么这类计算题有那些解法？原理如何？笔者在这里用下面的例题作一浅析．题目 某支刻度、内管都均匀的温度计在零下５℃时,显示－１０℃,而在４５℃时显示５２．５℃,那么在气温为２５℃时,它将显示 ℃,而在 ℃时,它显示的温度跟标准温度相同．（答案为２７．５;１５）一、定义法此法是根据摄氏度的定义来分析计算的,解题时关键在于找准标准０℃和非标准０℃处的位置,然后利用这一差值以及标准摄氏度和非标准摄氏度之间的关系解题．１．根… 相似文献
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体温表由三部分组成:玻璃球——盛放显示剂;玻璃管——呈三棱柱形,中心是一根很细的真空管,与玻璃球中的显示剂相连。棱柱的一边有一条乳白色、不透明的带状物作背衬,另一边标有刻度,以此显示水银体积变化与温度的关系;显示剂——体温表用水银做显示剂。水银是一种金属,常温状态下呈液态,对温度变化反映很灵敏。 体温表大都采用摄氏温标。量程为35～42℃, 相似文献
6.
《实验室研究与探索》2017,(8):10-13
通过超高真空反应磁控共溅射方法制备了CoTiO_2薄膜样品,在退火过程中加入了紫外光照射,研究了退火温度在反应共溅法中对薄膜微结构和磁性能的影响。形貌和结构研究表明,随着退火温度的升高样品的表面颗粒尺度逐渐减小,温度越高越有利于磁性相的形成,且500℃退火温度下锐钛矿结构的衍射峰较明显,晶胞变大;磁滞回线显示出样品呈现铁磁性特征,并且随着退火温度的升高样品的磁化强度逐渐降低;热磁曲线测量显示有序温度高于120℃。退火过程中进行辐照干预的处理,发现在薄膜制备过程中对薄膜的结构及磁性有重要影响。铁磁性有可能是起源于在热处理过程中引起的磁性离子和氧空位导致的晶格缺陷。 相似文献
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温度是影响人体舒适与否的最直接的气象要素。为了保持自身温度与外界温度的平衡,人体必须通过热辐射和汗液蒸发等方式与环境温度协调体温恒定。温度高时,人汗流浃背,排放热量;温度低时,则要穿上厚厚的棉衣抵御寒冷,防止热量散失。有资料显示,为了用最少的能量消耗把体温保持在36．5℃左右,需要使身体周围的温度保持在31．7℃上下。 相似文献
8.
目前微机技术已广泛应用于自动控制、智能仪器仪表、数据采集和处理、家用电器等各个方面,同时也渗透到其它各个科学领域。本文介绍笔者设计的,应用INTEL8031微处理器设计的测量温度系统;这个系统测温范围为0.1℃～999.9℃(根据需要改变选材,可以任意改变),它具有自动定时测量,自动显示温度大小的功能。它适用于一些不允许直接测量温度的场合。 相似文献
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本文介绍了基于单片机AT89C51的水温控制系统的设计方案与软硬件实现.采用温度传感器DS18B20采集温度数据,共阴极LED显示温度数据,按键设置可设置预置水温温度,当采集的温度低于设定值时,单片机启动电炉加热器加热,当温度等于或高于设定值时,单片机停止电炉加热器加热.能够实现最小区分度为1℃的水温控制.给出了系统的总体框架、各部分电路设计、总电路设计、程序流程图. 相似文献
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朱华贵 《乐山师范学院学报》2004,19(12):25-27
本系统运用主从分布式和总线分布式多机通讯方式思想，设计了一种可大规模多点温度测量的巡回检测系统。利用RS-485进行串行通讯，通过PC机发出控制指示，对各单片机从机进行现场温度采集，由PC机进行数据处理和显示。系统检测温度范围为0℃～400℃，分辨率可达到0．01℃，并可由PC机统一设置系统时间和温度修正值和设置各从机的温度报警上下限，主机、从机均具有声光报警功能和数据更新与掉电保护功能、打印功能，人机界面友好。本系统具有巡检速度快，扩展性好、分辨率高等特点。 相似文献
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Theoretical and experimental analysis of a new refrigerant mixture BY-3 was conducted based on a single-stage vapor compression refrigeration system. The water-water heat pump system used BY-3 to produce hot water when the low temperature was 20 ℃. The following results were obtained: the highest temperature at the condenser outlet reached about 85 ℃; when the difference between the water temperatures at the condenser outlet and the evaporator inlet was less than 40 ℃, the coefficient of performance (COP) was larger than 4; when the difference reached 55 ℃, the COP still kept 3; the discharge temperature of BY-3 was lower than 100 ℃, and the refrigerant vapor pressure kept lower than 1.8 MPa. When the water temperature at the condenser outlet reached over 85 ℃, nearly a 5 ℃ superheating temperature was maintained. 相似文献
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采用C15、C30、C40、C60、C80混凝土配合X衍射试验、差热试验和热膨胀试验,对不同标号的混凝土在不同组分及中高温下所发生的一系列物理化学变化进行了研究与分析,从而探讨温度对混凝土影响的一些因素,以及在相同温度条件下,不同标号的混凝土所表现的一些性质的差异,从而为工程中使用混凝土提供一些参考。通过多项试验分析,混凝土在受到高温时,必然会发生一些物理化学变化,从而使其强度下降并发生性能的衰减。同时,通过数据的比较发现,高标号的混凝土在高温下发生物理化学变化时所需的温度比低标号的混凝土要高,因此发生破坏的最终时间要相对滞后。 相似文献
13.
The production of elastase by Bacillus sp. EL31410 at various temperatures was investigated. In order to study the effect of temperature on elastase fermentation,
different cultivation temperatures, ranging from 39 °C to 28 °C, were evaluated in shake flask. The result indicated that
37 °C was best for cell growth at earlier stage; while maximum elastase activity was obtained when the cells were cultivated
at 30 °C. This result was verified by batch fermentation in 5-L bioreactor under 37 °C and 30 °C temperature, respectively.
The specific cell growth rate at 37 °C was higher than that at 30 °C during earlier stage of cultivation. The maximum value
[5.5 U/(h·g DCW)] of elastase formation rate occurred at 24 h at 30 °C compared to 4.6 U/(h·g DCW) at 30 h at 37 °C. Based
on these results, two-stage temperature shift strategy and oscillatory temperature cultivation mode were evaluated in the
next study. When compared to single temperature of 37 °C or 30 °C, both two-stage temperature shift strategy and oscillatory
temperature strategy improved biomass but did not yield the same result as expected for elastase production. The maximum biomass
(both 8.6 g/L) was achieved at 30 h at 37 °C, but at 42 h using two-stage temperature cultivation strategy. The highest elastase
production (652 U/ml) was observed at 30 °C in batch process. It was concluded that cultivation at constant temperature of
30 °C was appropriate for elastase production by Bacillus sp. EL31410.
Project (No. 20276064) supported by the National Natural Science Foundation of China 相似文献
14.
A novel voltage output integrated circuit temperature sensor 总被引：1，自引：0，他引：1
The novel integrated circuit (IC) temperature sensor presented in this paper works similarly as a two-terminal Zener, has breakdown voltage directly proportional to Kelvin temperature at 10 mV/℃, with typical error of less than ±1.0℃ over a temperature range from -50℃ to +125℃. In addition to all the features that conventional IC temperature sensors have, the new device also has very low static power dissipation ( 0.5 mW ) , low output impedance ( less than 1Ω), excellent stability, high reproducibility, and high precision. The sensor's circuit design and layout are discussed in detail. Applications of the sensor include almost any type of temperature sensing over the range of -50℃-+125℃. The low impedance and linear output of the device make interfacing the readout or control circuitry especially easy. Due to the excellent performance and low cost of this sensor, more applications of the sensor over wide temperature range are expected. 相似文献
15.
基于单片机AT89C52的智能温控箱采用温度传感器DS18B20采集温度数据,1602C型字符型液晶显示模块显示温度数据,按键设置温度上下限,并可改变加热元件的温控状态. 相似文献
16.
In this paper, a new ternary non-azeotropic mixture of HFC-161/125/143a (0.15/0.45/0.40 in mass fraction), as a promising
mixed refrigerant to R404A, is presented. The ozone depletion potential (ODP) of the new refrigerant is zero and its basic
thermodynamic properties are similar to those of R404A, but its global warming potential (GWP) is much smaller than those
of R507A and R404A. Meanwhile, theoretical calculations show that, under the working condition I (the average evaporation
temperature: −23 °C, the average condensing temperature: 43 °C, the superheat temperature: 28 °C, the subcooling temperature:
5 °C), the volumetric refrigerating effect and specific refrigerating effect of the new mixture are 2.33% and 15.48% higher,
respectively, than those of R404A. The coefficient of performance (COP) of the new mixture is 5.19% higher than that of R404A
and the pressure ratio of the new mixture is 0.82% lower than that of R404A. Equally, under the working condition II (the
average evaporation temperature: −40 °C, the average condensing temperature: 35 °C, the superheating temperature: 30 °C, the
subcooling temperature: 5 °C), the volumetric refrigerating effect and specific refrigerating effect of the new mixture are
2.24% and 20.58% higher, respectively, than those of R404A. The COP of the new mixture is 4.60% higher than that of R404A
and the pressure ratio of the new mixture is similar to that of R404A. The performances of the new mixture and R404A are compared
in a vapor compressor refrigeration apparatus originally designed for R404A under several working conditions (condensing temperatures:
35–45 °C, evaporation temperatures: −40–−20 °C). Experimental results show that the new mixture can obtain a higher COP, by
6.3% to 12.1%, and a lower pressure ratio, by 1.8% to 6.6%, compared to R404A; although the discharge temperature of the new
mixture is slightly higher than that of R404A. The advantages of the new mixture will be further verified in the actual system. 相似文献
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A temperature sensor is demonstrated and fabricated by coating the single-mode tapered optical fiber with temperature-sensitive silicone rubber. It works on the change of the evanescent fields in the tapered optical fiber. Small changes in the refractive index of coating film greatly influence the power of evanescent fields, which modulate the transmission optical power in the waist region. The range of temperature measured is from 20°C to 70°C. The results show that the temperature sensor has high temperat... 相似文献
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In order to select the appropriate working fluids and optimize parameters for medium-temperature geothermally-powered organic Rankine cycle(ORC), R245 fa is mixed with R601 a at geothermal water temperature of 110 ℃. Based on thermodynamics, the characteristics of mixture and its influence on the performance of ORC under different evaporating temperatures and composition proportions are analyzed. Results show that the zeotropic mixture R245fa/R601a(0.4/0.6) has the highest performance. When the evaporating temperature reaches 67 ℃, the outlet temperature of geothermal water is 61 ℃, the net power output is the highest and the thermal efficiency is about 9%. 相似文献
20.
Appropriate addition of CuO/V2O5 and the reduction of the granularity of the raw materials particle decrease the sintering temperature ofNiZn ferrite from 1200℃ to 930 ℃. Furthermore, the magnetic properties of the NiZn ferrite prepared at low temperature of 930℃ is superior to that of the NiZn ferrite prepared by sintering at high temperature of 1200 ℃ because the microstructure of the NiZn ferrite sintered at 930℃ is more uniform and compact than that of the NiZn ferrite sintered at 1200℃. The high permeability of 1700 and relative loss coefficient tanδ/μi of 9.0-10^-6 at 100 kHz was achieved in the (Ni0.17Zn0.63Cu0.20)Fe 1.915O4 ferrite. 相似文献