An overview on observational instruments and measuring methods for dewfall

This paper systematically summarizes previous measuring methods and observational instruments for the magnitude of dewfall on land surface, analyzes the characteristics of common observational instruments for land surface dewfall, and describes several basic dewfall measurement methods. Moreover, the basic principles of these methods and instruments are interpreted, and their advantages, disadvantages, and applicability are analyzed. Recommendations for the further improvement of these observational instruments and the development of dewfall measuring methods are presented, and new technologies and scientific proposals for exploiting dewfall are elucidated.

Measuring methods for three kinds of polyhydroxyalkanoates from activated sludge by gas chromatography

Gas chromatography determination of polyhydroxyalkanoates has been common;however,the pretreatment steps are often complex,and gas chromatography operation conditions are not given in detail.In this study,gas chromatography is used for analyzing PHB,PHV and PH2MV,three majors of PHAs in activated sludge.The sample was centrifuged at a speed of 4000 r/min for the separation of floc and supernatant,freezen,and dried for 12 h in vacuum freezing drier;and then transferred to the fridge for freezing to ice and drying for 12 h in vacuum freezing drier;then chloroform and a simple composition digestion solution including methanol,sulfuric acid and benzoic acid was added;digested at 105 ℃ for 6 h;cooled to room temperature,the lower solution of the result can be used for analyzing.Samples were analyzed by gas chromatography with FID detector and auto sampler;the standard curve of standard material shows an excellent linear relationship with correlation coefficients larger than 0.99;the relative standard deviation (RSD) of sludge samples is less than 1%.The recovery rates of each sample are between 95%-105%.The GC analysis time of each PHA sample is shorter than 10 minutes.

Drilling-based measuring method for the c-φ parameter of rock and its field application

The technology of drilling tests makes it possible to obtain the strength parameter of rock accurately in situ. In this paper, a new rock cutting analysis model that considers the influence of the rock crushing zone(RCZ) is built. The formula for an ultimate cutting force is established based on the limit equilibrium principle. The relationship between digital drilling parameters(DDP) and the c-φ parameter(DDP-cφ formula, where c refers to the cohesion and φ refers to the internal friction angle) is derived, and the response of drilling parameters and cutting ratio to the strength parameters is analyzed. The drillingbased measuring method for the c-φ parameter of rock is constructed. The laboratory verification test is then completed, and the difference in results between the drilling test and the compression test is less than 6%. On this basis, in-situ rock drilling tests in a traffic tunnel and a coal mine roadway are carried out, and the strength parameters of the surrounding rock are effectively tested. The average difference ratio of the results is less than 11%, which verifies the effectiveness of the proposed method for obtaining the strength parameters based on digital drilling. This study provides methodological support for field testing of rock strength parameters.

Re-measuring International Short-term Capital Flow into China with Varying Methods

This paper.fi＇rst conducts a systematic review of domestic and foreign scholars＇ approaches to predicting short-term capital flows, then employs a combination of both direct and indirect methods to carry out its analysis. Three kinds of indicators, both specific and general, are applied in both methods. Thorough consideration is given to short-term international capital inflow from trade, other current account items, capital account, and errors and omissions, as well as other channels through which short term capital might accrue to a nation＇s balance. Based on a comprehensive comparison of year-on-year data, this paper also estimates monthly data using a simplified, indirect calculation approach. Estimates show that, despite a degree of difference in results between methods, most estimates are highly consistent for a given period. Based on monthly estimates, we conclude that turbulence in international financial markets （i.e., the United States subprime mortgage crisis and the European sovereign debt crisis） has had a major impact on China ＇s short-term capital flow.

Magnetic field regression using artificial neural networks for cold atom experiments

Accurately measuring magnetic fields is essential for magnetic-field sensitive experiments in areas like atomic,molecular,and optical physics,condensed matter experiments,and other areas.However,since many experiments are often conducted in an isolated environment that is inaccessible to experimentalists,it can be challenging to accurately determine the magnetic field at the target location.Here,we propose an efficient method for detecting magnetic fields with the assistance of an artificial neural network(NN).Instead of measuring the magnetic field directly at the desired location,we detect fields at several surrounding positions,and a trained NN can accurately predict the magnetic field at the target location.After training,we achieve a below 0.3%relative prediction error of magnetic field magnitude at the center of the vacuum chamber,and successfully apply this method to our erbium quantum gas apparatus for accurate calibration of magnetic field and long-term monitoring of environmental stray magnetic field.The demonstrated approach significantly simplifies the process of determining magnetic fields in isolated environments and can be applied to various research fields across a wide range of magnetic field magnitudes.

Study on Measurement Methods of Multi-Directional Waves—Wave Gauge Array Method

Measuring multi-directional waves with the wave gauge array is one of the fundamental and easily realised methods. In this paper, the wave gauge array is described and the effects of the gauge spacing, the array orientations, etc. of the three array arrangements, i. e., linear array, T-type array and pentagon array, on the resolution of the directional spreading of waves, are investigated experimentally. This study can be used as a reference in the experimental study and the field measurement of directional waves.

A review of welding residual stress test methods

Due to local uneven heating during the welding process,the residual stress of the structure after welding affects the reliability of it.In order to ensure the reliability,it is of great significance to test the residual stress distribution of the welded joint.It has always been the focus to find a simple and feasible method for residual stress testing to quickly and accurately obtain the residual stress distribution of welded joints.The mechanical measurement method has high measurement accuracy,convenient and easy operation,but it will cause certain damage to the components.Physical measurement method can avoid damage to components,but its test cost is usually high,and its measurement accuracy can also be affected by the material microstructure characteristics of welded components.Based on the advantages and disadvantages of these two residual stress test methods,a modal test method is proposed.This method is a non-destructive measurement method.Based on the mathematical relationship between the residual stress of the welded structure and the natural frequency(mathematical model),the natural frequency is measured through the modal test to calculate the residual stress quickly.However,it is difficult to establish a mathematical model with this method,and it is not suitable for realization.

Self-heating Probe Instrument and Method for Measuring High Temperature Melting Volume Change Rate of Material

The castings defects are affected by the melting volume change rate of material. The change rate has an important effect on running safety of the high temperature thermal storage chamber, too. But the characteristics of existing measuring installations are complex structure, troublesome operation and low precision. In order to measure the melting volume change rate of material accurately and conveniently, a self-designed measuring instrument, self-heating probe instrument, and measuring method are described. Temperature in heating cavity is controlled by PID temperature controller; melting volume change rate υ and molten density are calculated based on the melt volume which is measured by the instrument. Positive and negative υ represent expansion and shrinkage of the sample volume after melting, respectively. Taking eutectic LiF＋CaF2 for example, its melting volume change rate and melting density at 1 123 K are -20.6% and 2 651 kg/m–3 measured by this instrument, which is only 0.71% smaller than literature value. Density and melting volume change rate of industry pure aluminum at 973 K and analysis pure NaCl at 1 123 K are detected by the instrument too. The measure results are agreed with report values. Measuring error sources are analyzed and several improving measures are proposed. In theory, the measuring errors of the change rate and molten density which are measured by the self-designed instrument is nearly 1/20-1/50 of that measured by the refitted mandril thermal expansion instrument. The self-designed instrument and method have the advantages of simple structure, being easy to operate, extensive applicability for material, relatively high accuracy, and most importantly, temperature and sample vapor pressure have little effect on the measurement accuracy. The presented instrument and method solve the problems of complicated structure and procedures, and large measuring errors for the samples with high vapor pressure by existing installations.

Measurement methods and analysis tools for rail irregularities:a case study for urban tram track

Rail irregularities, in particular for urban rail- way infrastructures, are one of the main causes for the generation of noise and vibrations. In addition, repetitive loading may also lead to decay of the structural elements of the rolling stock. This further causes an increase in main- tenance costs and reduction of service life. Monitoring these defects on a periodic basis enables the network rail managers to apply proactive measures to limit further damage. This paper discusses the measurement methods for rail corrugation with particular regard to the analysis tools for evaluating the thresholds of acceptability in re- lation to the tramway Italian transport system. Further- more, a method of analysis has been proposed： an application of the methodology used for treating road profiles has been also utilized for the data processing of rail profilometric data.

Analysis and Application of the Synthetic Relative Measuring Method in On-Line Monitoring for Capacitive Equipment in Power Systems

On-line measurement for dielectric loss angle can effectively monitor the insulation condition of capacitive equipment in power systems. Synthetic relative measuring methods not only markedly overcome the shortcomings of traditional absolute measuring methods but also greatly improve the accuracy of dielectric loss angle measurement. However, synthetic relative measuring methods based on two or three pieces of capacitive equipment do not have the characteristic of generality. In this paper, a principle of synthetic relative measuring method is presented. The example of application for synthetic relative methods based on three and four pieces of capacitive equipment running in the same phase is taken to present the failure judgment matrices for N pieces of equipment. According to these matrices, the fault condition of N pieces of capacitive equipment can be watched, which is more general. Then some problems needing to be concerned along with two diagnostic methods used in diagnostic system are introduced. Finally, two programmable flow charts for the two methods are given and corresponding examples demonstrate their feasibility in practice.

A New Method for Measuring the Wall Charge Waveforms of AC PDP

A new method is developed to measure the wall charge waveforms in coplanar alternating current plasma display panel (AC PDP). In the method, two groups of display electrodes are selected from a coplanar AC PDP and two capacitors are respectively connected with these two groups of display electrodes in series, and a measuring circuit and a reference circuit are thus constructed. With the help of special processing, discharge takes place in the cells included in the measuring circuit under a normal drive voltage but no discharge takes place in the cells included in the reference circuit under a normal drive voltage. The wall charge waveforms are obtained from the voltage difference between the two capacitors. Using the method, the wall charge waveforms are measured during resetting period, addressing period and sustaining period for the 304.8mm (12-inch) test PDP panel. The result shows that the wall voltage is about 96V during the sustaining period.

Thickness Method for Measuring Hair Density of Rex Rabbit

[Objective] The paper was to characterize hair density by changes in hair thickness under certain pressure.[Method] Tile effects of weight of thickness tester and wafer urea at the hottom of presser foot on measurement results were studied, and the optimal measuring weight and wafer diameter was determined. The measurement results of hair thickness under the ahove condition were compared with the results of manual counting. Meanwhile, the effects of hair length and hair fineness on hair density were analyzed.[Result] The hair density obtained by manual count- ing had consistent change trend with the hair thickness measured under certain conditions. If the length and fineness of hairs were introduced for modification, the correlation between hair thickness and hair density would be better. There were little changes in hair length and finelless of rex rabbit, and their effects on hair thickness could be ignored under general condition. [Conclusion] It is completely feasible to characterize hair den- sity of rex rabbit by hair thickness under pressure.

Application of a Soil Nutrient Measuring Instrument in Vegetable Seedling Substrate

[Objective] The aim was to find an efficient method to measure available nitrogen, phosphorus and potassium content in vegetable seedling substrate. [ Method] The suitable dosage of leaching agent, ratio of the substrate to water and leaching time for the detection of nutrient contents in the substrate by a soil nutrient measuring instrument were discussed firstly, and then the results of nutrient contents measured by the soil nutrient measuring instrument were compared with that by conventional approaches. [ Result] In compadson with the conventional methods, the av- erage content of available nitrogen measured by the soil nutrient measuring instrument was slightly higher, while the average content of available phosphorus measured by the instrument was lower; the average content of available potassium measured by the instrument was close to that by the conventional method. [ Conclusion] This study could provide us a new method to detect available nitrogen, phosphorus and potassium content in seedling substrate efficiently.

Single-borehole measuring method for broken rock zone in gently inclined thin layer weakness structure

According to the structural characteristics of gently inclined thin layer rock mass in which lots of weak interlayer existed,the concept of gently inclined thin layer weakness structure was proposed.If single-borehole measuring method of the acoustic along the conventional arrangement mode was used in measuring the broken rock zone in this structure,the change of the relationship curves (Vp-L) between acoustic p-wave velocity (Vp) and borehole depth (L) would present the irregular feature due to the mechanical characteristics of layered rock mass and harmful effects of weak interlayers,and the scope of broken rock zone couldn't be defined quickly.Based on the analysis of the me- chanical characteristics of layered rock mass,the propagation rule of acoustic and distri- butions characteristics of plastic zone and slip zone in layered rock mass,new arrange- ment mode of acoustic measuring boreholes for broken rock zone in gently inclined thin layer weakness structure was proposed.Namely,the measuring boreholes in two sides were parallel to the strata,the measuring boreholes in the roof and floor perpendicular to the strata.Besides the controlling depth of the measuring boreholes in the scope of the large plastic zones or the large slip zones should be increased.Engineering example showed that new acoustic measuring boreholes arrangement mode had the better appli- cability and could determine the scope of the broken rock zone in the gently inclined thin layer weakness structure quickly.

Three Measurement Methods of Two-photon Absorption Cross-section

Through the experimental design and theoretical analysis, three technologies used for characterizing the two-photon absorption(TPA) properties, such as nonlinear transmission experiment and theory, Z-scan technology and two-photon induced fluorescence method, are introduced. The properties of the three experiments to be utilizable and realizable under desirable limitation are simply analyzed. The advantages of the measurements for TPA characterization are also analyzed.

Measuring Method for Shunt Resistance of Solar Cell

Shunt resistance of solar cell must be monitored for large area solar cell manufactured with conventional process.A measuring method for the shunt resistance is derived from direct-current model.The shunt resistance of solar cell is obtained only by treating a part of I-V data.

Recent progress in research and design concepts for the characterization,testing,and photocatalysts for nitrogen reduction reaction

The reduction of molecular nitrogen(N_(2))to ammonia(NH_(3))under mild conditions is one of the most promising studies in the energy field due to the important role of NH_(3)in modern industry,production,and life.The photocatalytic reduction of N_(2)is expected to achieve clean and sustainable NH_(3)production by using clean solar energy.To date,the new photocatalysts for photocatalytic reduction of N_(2)to NH_(3)at room temperature and atmospheric pressure have not been fully developed.The major challenge is to achieve high light-absorption efficiency,conversion efficiency,and stability of photocatalysts.Herein,the methods for measuring produced NH_(3)are compared,and the problems related to possible NH_(3)pollution in photocatalytic systems are mentioned to provide accurate ideas for measuring photocatalytic efficiency.The recent progress of nitrogen reduction reaction(NRR)photocatalysts at ambient temperature and pressure is summarized by introducing charge transfer,migration,and separation in photocatalytic NRR,which provides a guidance for the selection of future photocatalyst.More importantly,we introduce the latest research strategies of photocatalysts in detail,which can guide the preparation and design of photocatalysts with high NRR activity.

Express Methods for Measurement of Electroconductivity of Semiconductor Layered Crystal

We describe theoretically the grounded method of measuring the conductivity of anisotropic layered semiconductor materials. The suggested method implies the use of a four-probe testing device with a linear arrangement of probes. The final expressions for identifying the electrical conductivity are presented in the form of a series of analytic functions. The suggested method is experimentally verified, and practical recommendations of how to apply it are also provided.

A review on stress determination and control in metal-based additive manufacturing

Metal additive manufacturing(MAM)is an emerging and disruptive technology that builds three-dimensional(3D)components by adding layer-upon-layer of metallic materials.The complex cyclic thermal history and highly localized energy can produce large temperature gradients,which will,in turn,lead to compressive and tensile stress during the MAM process and eventually result in residual stress.Being an issue of great concern,residual stress,which can cause distortion,delamination,cracking,etc.,is considered a key mechanical quantity that affects the manufacturing quality and service performance of MAM parts.In this review paper,the ongoing work in the field of residual stress determination and control for MAM is described with a particular emphasis on the experimental measurement/control methods and numerical models.We also provide insight on what still requires to be achieved and the research opportunities and challenges.