Q. Li's research while affiliated with National Institute of Metrology and other places

Publications (14)

Article
To address the issues related to the excessive use of nitrogen fertilizer and the low transplanting density in rice, the effects of reduced or increased nitrogen density on rice yield and nitrogen use efficiency were investigated, so as to provide a scientific basis for optimizing the production of rice in the cold region of northeast China. A fiel...
Article
[Objectives] The effects of different amounts of potassium (K) fertilizer on rice yield, K utilization efficiency and the capacity of soil K supply under straw return in rice production region of northeast China were systematically studied, in order to provide scientific basis for rational K fertilizer application under straw return of rice. [Metho...
Article
To study the control and non-linear correction of a large-scale two-dimensional nanometer displacement stage, a micro-displacement measurement system which based on the measurement principle of a laser interferometer was setted up.The composition of the dual-frequency laser interferometer measurement system was introduced, the control program of na...
Article
A tungsten probe fabrication device is proposed based on electrochemical etching method and the parameter of fabricating tungsten probe is researched.The experimental part can be used to adjust the relative position and motion parameters of the probe and the electrolyzer.The control part can be used to control and record the state of electrochemica...
Article
Since the high precision performance index of micro/nano coordinate measuring machine cannot be calibrated accurately, an indirect calibration solution is proposed. The measurement indication error of the micro/nano coordinate measuring machine is measured by gauge blocks and ball plate with hemispheres; The probing error is measured by calibration...
Article
The shear piezoceramics stack micro-displacement measurement system is built. The second-order, third-order, forth-order least square fitting formulas of voltage with displacement are obtained by the micro-displacement measurement experiments of 5 different target voltage. The result of nonlinear correction used by the third-order least square fitt...
Article
In order to solve the deficiency in precise measurement of micro-nano geometry structure dimension under 100nm of scanning electron microscope(SEM) and realize the quantity transfer and traceability of measurement values, the control and measuring system of metrological SEM is developed. The system consists of the motion control module of positioni...
Article
The atomic force microscope (AFM) scanning head based on the qPlus technology is preliminarily designed and assembled. The silicon cantilever sensor is replaced by quartz tuning fork type force sensor. Preamplifier circuit is designed and frequency characteristic of this scanning head is also analyzed. Finally, the experimental device for this scan...
Article
A two-dimensional nanometer displacements of using piezoelectric ceramic (PZT) to drive overlay of flexure hinge mechanism is developed. The structure of displacement system is introduced and the job of displacement stiffness is analyzed. The theoretical and simulation result error is below 6.3%. Constructed a laser interferometer based on the prin...
Article
The micro-nano linewidth measurement technology on metrological ultraviolet microscope is use the photovoltaic effect of photomultiplier tubes to convert the optical signal to electric signal and extract the outline of linewidth by the subsequent signal acquisition circuit. Using some precision positioning device, such as laser interferometer, buil...
Article
According to the needs of calibrating the probing size error, a method based on the standard balls for the calibration of industrial CT probing size error is proposed and factors which cause the probing size error are detailly analyzed. Firstly, it calibrates the diameter by the length-measuring machine of National Institute of Metrology, then cali...
Conference Paper
The atomic force microscope (AFMs) is widely used in nanotechnology research and industry. To ensure the quantity consistency, the measurement precision of these machines must be calibrated and trace back to SI international unit. In the calibration process, first the standard grating pitch artifact is calibrated by metrological atomic force micros...
Article
A constant temperature control system is design based on the thermoelectric cooler. Thermocouple is used as a temperature measurement sensor, whose measurement uncertainty is 6.6mK used in narrow temperature interval. The main thermostat and auxiliary thermostat core is MAX1978.The design goal of the main thermostat is to provide ±0.01°C temperatur...

Citations

... However, compared with traditional CMMs, the ICT system includes not only the basic motion mechanism, but also X- ray source, detector, image reconstruction algorithms and other complex parts, which makes the measurement traceability become extremely hard. Researchers all around the world have made a lot of valuable research on the calibration methods and reference standards of ICT [2,3,4,5,6] . But currently there isn't any general consent resolution for the calibration of ICT. ...
... Straw deep-burying, a type of straw return approach, has already been widely used to reduce soil evaporation and benefit agriculture. In addition, straw buried in the soil can enrich soil organic matter and nutrient elements such as nitrogen, phosphorus, and potassium [11,12], which is important for coastal tidal soil by enhancing soil quality and increasing agricultural productivity. Wang et al. [13] also revealed that a buried straw layer changed the original soil physical structure, reduced the soil bulk density, enriched the soil pore structure, and enhanced the soil ventilation permeability. ...