共查询到20条相似文献，搜索用时 46 毫秒
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A new type of measuring instrument which is used to measure lead errors of ballscrews has been developed. The principle of the inStrument,the system strucrure,the computer inter-face. The analyses of the instrument error and the experimental results are presented, The principleof comparing synchronous displacement is used to achieve absolute measurement. The errors correc-tion technique is adopted to correct the errors of the instrument so that the high measuring accuracycan be botained. 相似文献
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YANG Hong-Tao 《保鲜与加工》2004,(3):122-124
This paper introduces the definition of the quasi-dunamic instrument, analyzes the measuring principle of the double-theodolite space coordinate quasi-dynamic measuring system, builds the experimental system with the currency theodolite and designing the accessorial driving and orientational framework, investigates the dynamic character under variant tracking velocity of this system by the experiments and gians some elementary conclusions. These conclusions play important roles in the compensating the measuring error and in the improving the measuring precision of the measuring system. 相似文献
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For the requirement of building up the battery management system (BMS) of hybrid vehicles(HEVs), the real time measurement and estimation of charge (SOC) of the Ni MH batteries are investigated, because the popular SOC definition is unsuitable under the condition of variable current discharge. The origin of this kind unsuitability are analyzed ,and the characteristics and existing problems of different kinds of SOC measuring methods are compared. On the basis of mentioned above, some corrections are given to the popular SOC definition, and the new conception of SOC is proposed. The corrected definition of SOC is suitable for the real time SOC estimation under the variable current condition of the batteries used in HEVs. Based on the corrected SOC definition, the computational model of the new SOC is built and simulated. Satisfactory result has been obtained from comparisons of the simulating results, which shows that the theoretical model provides a basis for optimizing the adaptation of power system to the hybrid vehicles (HEVs). 相似文献
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多糖的定义、构成及范围较复杂,其测定方法目前还没有国标,文献报道的方法基本上是苯酚—硫酸法和蒽酮—硫酸法,但是试验中存在重现性差的缺陷。根据"粗多糖=总糖-还原糖"的原理推导出"活性多糖=总糖-可溶糖-淀粉"新测定方法,解决了重现性差的问题。 相似文献
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Tang Chaowei Liang Xichang Zou Changping 《保鲜与加工》1993,(1):107-111
Traditionally, the surface contour instrument or three-coordinate machine was used in 3-D curued surfaces measuring system. Now triangle measuring device using laser is installed on the three-coordinate machine and replaces the contact pin. But this method is still limited by the three-coordinate machine itself. On the basis of studying the principle of trinagle the measuring method,this paper has put forward to the two-triangle measuring system and given out the designing method. 相似文献
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In practical application, plane measuring instrument is mainly used to test flatness of workpiece in micro level, so that people can check if the workpiece is qualified or not. High resolution and high stabilization are two key technologies. The method of resolution extension is presented for improving the resolution of workpiece,and a signal source with high stabilization, which is designed by microcontroller and Complex Programmable Logic Device(CPLD), improves the stabilization of the system. The paper propose work principle and test step, the design of hardware,and introduces the measure for improving precision. The system is consisted of a position transducer, a signal source with high stabilization, a microcontroller and a signal processing unit. It has many advantages such as high resolution, high stabilization, low cost and simple operation, It also has been formally put to use in Chongqing Actaris Measurement Instrument Co.Ltd. now. 相似文献
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冰点温度的准确测定是确定食品适宜贮藏温度的关键。针对当前冰点测定方法和设备存在着测定周期长、成本较高以及设备移动不便等缺陷,本研究优化设计出一种新型的半导体制冷测定装置。该制冷装置利用半导体制冷快速降温,通过记录仪中的样品降温曲线可以清楚看到被测定样品的降温过程和相应的过冷点、冰点及整个相变过程。采用该装置对猪肉、苹果、牛奶葡萄、黄瓜、牛奶多种典型食品的过冷点和冰点进行测定。结果表明,与现有过冷点、冰点测定技术和装置相比,该测定装置具有小巧灵活,操作便利,精确度高,测定周期短、成本低的优势,而且测定过程中噪音极小,适于在冰温贮藏领域广泛应用。 相似文献
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The concept of essential derivation refers to cases where a new variety is obtained from an initial variety (IV), of which it retains the expression of the essential characteristics resulting from the genotype or combination of genotypes of the IV. Protecting plant breeder's rights can be facilitated by identifying a species‐specific threshold level of similarity above which the new variety could be suspected as essentially derived (EDV). Amplified fragment length polymorphisms and simple sequence repeats proved suitable for measuring genetic similarity. Three approaches have been proposed for the definition of thresholds. According to the ‘calibration principle’, the critical level to discriminate EDVs is defined based on similarities among closely related genotypes. Adopting the ‘tail principle’, the threshold is placed at a given percentile of the distribution of the similarities within a reference population of independent genotypes. Finally, with the ‘pedigree principle’, the threshold is set starting from the a priori definition of breeding techniques that lead to EDVs. The tools and the approaches described in this review represent the basis for developing protocols useful in handling disputes of essential derivation. 相似文献
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Erythrocyte is cardinal component in blood, the membrane viscoelastic properties of which plays an important role for the blood streaming movement. This article makes a review on the factors upon the membrane viscoelastic properties of erythrocyte as well as its measuring methods, and indicates the purpose of the researches on the membrane viscoelastic properties of erythrocyte to improve the blood streaming movement properties and new drug designing. 相似文献
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DAI Gao-fei~ 《保鲜与加工》2004,(2):132-135166
It is important that monitor measuring is applied in tunnel in regard to NATM. The monitor measuring of NATM was studied in the Fengmeiya Tunnel in Chongzun Express. Based on the regularity and conditions of the surrounding rock deformation of monitor measuring in site, the optimum time for primary and permanent support are obtained which averting successfully accidents in construction, enhancing the construction qualities and guidance to tunnel construction in Karst areas. 相似文献
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为了验证AutoCAD在测量苹果砧木枝条解剖结构中的应用,以2年生Y-1苹果矮化砧木植株为试材,实例介绍了用AutoCAD软件测量解剖结构组织长度及面积的方法,通过分别用IPE法和AutoCAD法测量了精确1mm和1mm2台尺的长度,苹果砧木Y-1 1年生枝各组织厚度、不同部位导管及筛管面积,比较了2种方法的精确度及对苹果砧木枝条解剖结构各组织测量值的差异显著性。结果表明,和IPE法相比,AutoCAD法测量精确度较高,且用2种方法测量苹果砧木Y-1 1年生枝横断面各组织厚度及面积的测量值差异不显著。得出,用AutoCAD软件对苹果砧木1年生枝横断面各组织厚度和面积进行测量比用IPE软件更精确、便捷,功能强大,提出用AutoCAD软件测量苹果砧木枝条解剖结构各组织长度与面积是一种值得推荐的方法,可在其他植物组织解剖结构的显微测量中推广应用。 相似文献
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Several methods of measuring surface vescosity are discussed. An appropriate method for measuring surface viscosity of melting slag- the laser method is proposed as well as an experimental device is set. With the device the surface viscosities of some aqueors liguids are measured. The results verify that the device is feasible and lays a good foundation for measuring the surface viscosity of melting slag. 相似文献
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This paper described the methods of measuring the powder concentration with scattering theory. We mainly discussed and compared the measuring methods with the extinction theory and Mie theory. Compared with the result which was worked out with the powder particles whose size are single, we analyzed the result worked out with the powder particles whose size obey some function. The Rosin-Rammler function is introduced to describe concentration and mean diameter. The difference between these two results was disussed. Then we simulated the result about coom by computer. The result is shown by the chart given. 相似文献
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When measuring, virtual instruments are inevitable to cause error damaging the precision of measuring resuits. It presents error constitution, methods of error transfer and synthesis of virtual measuring instrument. Based on the analysis of error transfer and synthesis of virtual measuring tual measuring instrument and gets the method of dealing instrument, it generalizes the error constitution formula of virwith errors. Then, errors can be modifyed. 相似文献
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酶联免疫吸附法测定黄曲霉毒素B_1不确定度的评定 总被引：2，自引：0，他引：2
王天西 《农产品加工．学刊》2008,(12)
采用ELISA方法测定黄曲霉毒素B1,结合分析测试中测量不确定度及评定的方法程序,对测定过程中重复测量、工作曲线拟合、电子天平、酶标仪等引入的不确定度分量进行评定,计算出黄曲霉毒素B1的合成不确定度为8.57×10-2,有效自由度为5,扩展不确定度为0.22。结果表示为(9.69±0.22)ng/g。 相似文献
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The traditional Automobile-inertia -brake-testing-system adopts the Mechanical Inertia pan to imitate automobile the Moving Inertia. This kind of system volume is bigger than new one, more difficult in inertia adjusting, and lower in automation degree. Aiming at the problems, this paper puts forward the innovative design of Automobile-inertia-brake-testing-system based on electrical inertia. The mathematic model of the Mechanical Inertia is analyzed. To use the algorithm to control motor, the authors make the output inertia generated by the controlled motor can imitate the Mechanical Inertia, then apply electrical inertia to replace Mechanical Inertia .The simulation result shows that the design idea is correct and feasible, stronger in system rubustness, lower in cost, more accurate in control quality, and higher in automation level. 相似文献
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Liao Ruijin Sun Caixin Gu Leguan Lu Shenghe 《保鲜与加工》1998,(4):44-48
The problem that the internal electrical interference is nuavoidable for differential coil in measuring fast high current impulse is discussed.The shielded differential coil which has a chink in the middle of its shield can reduce this interference,and that the signal to noise ratio of the differential measurement is 27 shows the anti interference efficiency of this coil.Furthermore,the double differential coil which use the differential balanced technique to resisting the interference make the signal to noise ratio of the differential mearsurement be 57. 相似文献
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为了使土壤硝化强度的测定条件更加统一,结果更加准确,本研究针对土壤硝化强度测定时广泛采用的悬液法,研究了其最佳培养条件：反应体系pH 7.5,底物NH4+-N浓度为100 mg/L,培养温度为30℃,培养时间为5 h,风干土样预培养72 h后才可进行硝化强度的测定。还针对NO3--N生成法的不足,探讨了通过NO2--N生成法评价硝化强度的途径：通过向反应体系中添加1 mol/L的氯酸钠0.2 mL,有效抑制NO2-向NO3-的氧化。不同检测方法对硝化强度测定对比的结果发现,NO2--N生成法确是评价土壤硝化强度的最佳方法。 相似文献