The influences of canopy temperature measuring on the derived crop water stress index

Crop water stress index(CWSI)is widely used for efficient irrigation management.Precise canopy temperature(T_(c))measurement is necessary to derive a reliable CWSI.The objective of this research was to investigate the influences of atmospheric conditions,settled height,view angle of infrared thermography,and investigating time of temperature measuring on the performance of the CWSI.Three irrigation treatments were used to create different soil water conditions during the 2020-2021 and 2021-2022 winter wheat-growing seasons.The CWSI was calculated using the CWSI-E(an empirical approach)and CWSI-T(a theoretical approach)based on the T_(c).Weather conditions were recorded continuously throughout the experimental period.The results showed that atmospheric conditions influenced the estimation of the CWSI;when the vapor pressure deficit(VPD)was>2000 Pa,the estimated CWSI was related to soil water conditions.The height of the installed infrared thermograph influenced the T_(c)values,and the differences among the T_(c)values measured at height of 3,5,and 10 m was smaller in the afternoon than in the morning.However,the lens of the thermometer facing south recorded a higher T_(c)than those facing east or north,especially at a low height,indicating that the direction of the thermometer had a significant influence on T_(c).There was a large variation in CWSI derived at different times of the day,and the midday measurements(12:00-15:00)were the most reliable for estimating CWSI.Negative linear relationships were found between the transpiration rate and CWSI-E(R^(2)of 0.3646-0.5725)and CWSI-T(R^(2)of 0.5407-0.7213).The relations between fraction of available soil water(FASW)with CWSI-T was higher than that with CWSI-E,indicating CWSI-T was more accurate for predicting crop water status.In addition,The R^(2)between CWSI-T and FASW at 14:00 was higher than that at other times,indicating that 14:00 was the optimal time for using the CWSI for crop water status monitoring.Relative higher yield of winter wheat was obtained with average seasonal values of CWSI-E and CWSI-T around 0.23 and 0.25-0.26,respectively.The CWSI-E values were more easily influenced by meteorological factors and the timing of the measurements,and using the theoretical approach to derive the CWSI was recommended for precise irrigation water management.

Diurnal Variation of Soil CO2 Efflux and Its Optimal Measuring Time-window of Temperate Meadow Steppes in Western Songnen Plain, China

In order to study the diurnal variation of soil CO2 effiux from temperate meadow steppes in Northeast China, and determine the best time for observation, a field experiment was conducted with a LI-6400 soil CO2 flux system under five typical plant communi- ties （Suaeda glauca （Sg）, Chloris virgata （Cv）, Puecinellia distans （Pd）, Leymus chinensis （Lc） and Phragmites australis （Pa）） and an alkali-spot land （As） at the meadow steppe of western Songnen Plain. The results showed that the diurnal variation of soil CO2 effiux exhibited a single peak curve in the growing season. Diurnal maximum soil respiration （Rs） often appeared between 1 1：00 and 13：00, while the minimum occurred at 21：00-23：00 or before dawn. Air temperature near the soil surface （Ta） and soil temperature at 10 cm depth （Tlo） exerted dominant control on the diurnal variations of soil respiration. The time-windows 7：00-9：00 could be used as the optimal measuring time to represent the daily mean soil CO2 effiux at the Cv, Pd, Lc and Pa sites. The daily mean soil CO2 effiux was close to the soil COz effiux from 15：00 to 17：00 and the mean of 2 individual soil CO2 effiux from 15：00 to 19：00 at the As and Sg sites, respectively. During nocturnal hours, negative soil CO2 fluxes （CO2 downwards into the soil） were frequently observed at the As and Sg sites, the magnitude of the negative CO2 fluxes were 0.10-1.55 gmol/（m2.s） and 0.10-0.69 gmol/（m2.s）at the two sites. The results im- plied that alkaline soils could absorb CO2 under natural condition, which might have significant implications to the global carbon budget accounting.

Integrated method for measuring distance and time difference between small satellites

The advancement of small satellites is promoting the development of distributed satellite systems,and for the latter,it is essential to coordinate the spatial and temporal relations between mutually visible satellites.By now,dual one-way ranging(DOWR)and two-way time transfer(TWTT)are generally integrated in the same software and hardware system to meet the limitations of small satellites in terms of size,weight and power(SWaP)consumption.However,studies show that pseudo-noise regenerative ranging(PNRR)performs better than DOWR if some advanced implementation technologies are employed.Besides,PNRR has no requirement on time synchronization.To apply PNRR to small satellites,and meanwhile,meet the demand for time difference measurement,we propose the round-way time difference measurement,which can be combined with PNRR to form a new integrated system without exceeding the limits of SWaP.The new integrated system can provide distributed small satellite systems with on-orbit high-accuracy and high-precision distance measurement and time difference measurement in real time.Experimental results show that the precision of ranging is about 1.94 cm,and that of time difference measurement is about 78.4 ps,at the signal to noise ratio of 80 dBHz.

A time-dependent measuring system for welding deformation

In this paper the establishment and application of a time dependent measuring system for welding deformation are presented which is established with high quality sensors shielded from strong welding interference. By using this system, vertical and horizontal displacements of the high temperature area are surveyed at the same time. And this system is also used for monitoring and controlling the deformation of real welded structures.

Effect of Measurement Time on Emission Flux of CO_2 and N_2O in Black Soil Region

[Objective] The aim was to investigate and reveal effect of measurement time on emission flux of CO2 and N2O to ensure the optimum time of emission flux, in order to provide scientific reference for emission reduction of greenhouse gas in black soil region. [Method] Based on experiment of long-term fertilizer location in black soil region, the paper studied on daily dynamic variation of CO2 and N2O discharge in 3 key growth periods （booting stage, grain-filling stage and mature stage） to reveal differences of CO2 and N2O emission flux in different times. [Result] Daily variations of CO2 and N2O emission flux were large, from 205 mg/（m2·h） to 552 mg/（m2·h） for CO2 and from 51 h to 295 μg/（m2·h） for N2O. Trend of CO2 discharge in different growth times showed a unimodal curve, and the peak was at noon of 12：00 and the peak valley was at 3：00 am; discharge of N2O was small in day time at booting stage and large at night. Regardless of rice growth period effect on CO2 and N2O emission flux, representative time of CO2 discharge was 6：00-8：00 or 16：00-21：00; and time of N2O was 8：00-10：00 or 16：00-21：00; if CO2 and N2O emission fluxes were measured simultaneously, the optimum time was 16：00-18：00; if the measurement was started during 9：00-12：00, correction coefficients of CO2 and N2O were 0.81 and 0.90, respectively. [Conclusion] The result provided scientific reference for reduction of greenhouse gas emission in black soil region.

Approach to inter-satellite time synchronization for micro-satellite cluster

Micro-satellite cluster enables a whole new class of missions for communications, remote sensing, and scientific research for both civilian and military purposes. Synchronizing the time of the satellites in a cluster is important for both cluster sensing capabilities and its autonomous operating. However, the existing time synchronization methods are not suitable for microsatellite cluster, because it requires too many human interventions and occupies too much ground control resource. Although, data post-process may realize the equivalent time synchronization, it requires processing time and powerful computing ability on the ground, which cannot be implemented by cluster itself. In order to autonomously establish and maintain the time benchmark in a cluster, we propose a compact time difference compensation system（TDCS）, which is a kind of time control loop that dynamically adjusts the satellite reference frequency according to the time difference. Consequently, the time synchronization in the cluster can be autonomously achieved on-orbit by synchronizing the clock of other satellites to a chosen one＇s. The experimental result shows that the standard deviation of time synchronization is about 102 ps when the carrier to noise ratio（CNR） is 95 d BHz, and the standard deviation of corresponding frequency difference is approximately0.36 Hz.

ABSOLUTE CONTINUITIES OF EXIT MEASURES AND TOTAL WEIGHTED OCCUPATION TIME MEASURES FOR SUPER-α-STABLE PROCESSES

Suppose X is a super-α-stable process in R^d, （0 〈 α〈 2）, whose branching rate function is dr, and branching mechanism is of the form ψ（z） = z^1＋β （0 〈0 〈β ≤1）. Let Xγ and Yγ denote the exit measure and the total weighted occupation time measure of X in a bounded smooth domain D, respectively. The absolute continuities of Xγ and Yγ are discussed.

Assessing the Impact of the Lead/Lag Times on the Project Duration Estimates in Highway Construction

The literature mentions multiple factors that can affect the accuracy of estimating the project duration in highway construction,such as weather,location,and soil conditions.However,there are other factors that have not been explored,yet they can have significant impact on the accuracy of the project time estimate.Recently,TxDOT raised a concern regarding the importance of the proper estimating of the lead/lag times in project schedules.These lead/lag times are often determined based on the engineer’s experience.However,inaccurate estimates of the lead/lag time can result in unrealistic project durations.In order to investigate this claim,the study utilizes four time sensitivity measures(TSM),namely the Criticality Index(CI),Significance Index(SI),Cruciality Index(CRI),and the Schedule Sensitivity Index(SSI)to statistically analyze and draw conclusions regarding the impact of the lead/lag time estimates on the total duration in highway projects.An Excel-based scheduling software was developed with Monte Carlo simulation capabilities to calculate these TSM.The results from this paper show that the variability of some lead/lag times can significantly impact the accuracy of the estimated total project duration.It was concluded that the current practices used for estimating the lead/lag times are insufficient.As such,it is recommended to utilize more robust methods,such as the time sensitivity measures,to accurately estimate the lead/lad times in the projects scheduled.

Thermal Effect of the Cable-Stayed Bridge Tower

This paper studies the thermal effect of the cable-stayed bridge tower based on full time accurate measurement and finite element analysis on Xiantao Hanjiang River Highway Bridge. The measured results and the displacement variation of top tower show that the tower rotates periodically when it is exposed in sunshine. But the tower column will not decline when there is no sunshine. In spite of in winter or in summer, the period when the tower column changed smallest is from 0∶00 am to 5∶00 am. The time period when the tower column has maximum deviation lags behind the time when the tower column has maximum temperature difference, and this phenomenon is obvious in winter. The conclusions also have directive value in predicting the tower deformations and their directions in construction control of cable-stayed bridge, and in verifying the finite element program.

Prototype of the readout electronics for the RICH PID detector in the STCF

The ring imaging Cherenkov(RICH) detector for particle identification(PID) is being evaluated for the future super tau-charm facility(STCF) complex. In this work, the prototype readout electronics for the RICH PID detector is designed. The prototype RICH PID detector is based on a thick gas electron multiplier combined with a micromegas detector for Cherenkov light detection. Considering that there will be a large number(~ 690,000) of detector channels in future RICH detector, the readout electronics faces many challenges to precisely measuring time and charge information, such as reducing the noise,increasing density, and improving precision. The requirements of the readout electronics are explored, the downselection of the ASICs is made and thus a prototype readout electronics is designed and implemented. Tests are also conducted to evaluate the performance of the prototype readout electronics, and the results indicate that the time resolution is better than ~ 1 ns(RMS) when the input charge is greater than ~ 12 fC based on the APV25chip, while the time resolution is better than ~ 1 ns(RMS) at an input charge of over ~ 48 fC based on the AGET and STCF ASIC chips, and the equivalent noise charge is better than ~ 0.5 fC(RMS) @ 20 pF based on the three ASICs. The test results indicate that the prototype readout electronics design meets the requirement of the future RICH PID detector and thus provides a reference for future engineering.

Energy and flux measurements of laser-induced silver plasma ions by using Faraday cup

Silver(Ag)plasma has been generated by employing Nd:YAG laser(532 nm,6 ns)laser irradiation.The energy and flux of ions have been evaluated by using Faraday cup(FC)using time of flight(TOF)measurements.The dual peak signals of fast and slow Ag plasma ions have been identified.Both energy and flux of fast and slow ions tend to increase with increasing irradiance from 7 GW cm-2 to 17.9 GW cm-2 at all distances of FC from the target surface.Similarly a decreasing trend of energies and flux of ions has been observed with increasing distance of FC from the target.The maximum value of flux of the fast component is21.2×10^(10) cm^(-2),whereas for slow ions the maximum energy and flux values are 8.8 keV,8.2×10^(10) cm^(-2) respectively.For the analysis of plume expansion dynamics,the angular distribution of ion flux measurement has also been performed.The overall analysis of both spatial and angular distributions of Ag ions revealed that the maximum flux of Ag plasma ions has been observed at an optimal angle of~15°.In order to confirm the ion acceleration by ambipolar field,the self-generated electric field(SGEF)measurements have also been performed by electric probe;these SGEF measurements tend to increase by increasing laser irradiance.The maximum value of 232 V m^(-1) has been obtained at a maximum laser irradiance of 17.9 GW cm^(-2).

Success and Incoherence of Orthodox Quantum Mechanics

Orthodox quantum mechanics is a highly successful theory despite its serious conceptual flaws. It renounces realism, implies a kind of action-at-a-distance and is incompatible with determinism. Orthodox quantum mechanics states that Schr&oumldinger’s equation (a deterministic law) governs spontaneous processes while measurement processes are ruled by probability laws. It is well established that time dependent perturbation theory must be used for solving problems involving time. In order to account for spontaneous processes, this last theory makes use of laws valid only when measurements are performed. This incoherence seems absent from the literature.

Data-driven Detection and Identification of Line Parameters with PMU and Unsynchronized SCADA Measurements in Distribution Grids

Line parameters play an important role in the control and management of distribution systems.Currently,phasor measurement unit(PMU)systems and supervisory control and data acquisition(SCADA)systems coexist in distribution systems.Unfortunately,SCADA and PMU measurements usually do not match each other,resulting in inaccurate detection and identification of line parameters based on measurements.To solve this problem,a data-driven method is proposed.SCADA measurements are taken as samples and PMU measurements as the population.A probability parameter identification index(PPII)is derived to detect the whole line parameter based on the probability density function(PDF)parameters of the measurements.For parameter identification,a power-loss PDF with the PMU time stamps and a power-loss chronological PDF are derived via kernel density estimation(KDE)and a conditional PDF.Then,the power-loss samples with the PMU time stamps and chronological correlations are generated by the two PDFs of the power loss via the Metropolis-Hastings(MH)algorithm.Finally,using the power-loss samples and PMU current measurements,the line parameters are identified using the total least squares(TLS)algorithm.Hardware simulations demonstrate the effectiveness of the proposed method for distribution network line parameter detection and identification.

A non-contact real-time measurement of lamp dimension based on machine vision

In order to realize the online measurement of lamp dimension,the bulb image dimension measurement based on vision(BIDMV)is proposed.The image of lamp is obtained by camera.After image processing,such as Otsu algorithm,median filter,ellipse fitting and envelope rectangle fitting,the dimension of lamp can be calculated.Based on this method,a non-contact real-time measurement system of the lamp’s dimension is developed.The precision of the proposed method is 0.07 mm,and it can satisfy the tolerance of the National Standard GB15766.1-2008.The experiment results show that the proposed method has a faster measuring speed and a higher precision compared with other measurement methods.

Precise time scales and navigation systems:mutual benefits of timekeeping and positioning

The relationship and the mutual benefits of timekeeping and Global Navigation Satellite Systems(GNSS)are reviewed,showing how each field has been enriched and will continue to progress,based on the progress of the other field.The role of GNSSs in the calculation of Coordinated Universal Time(UTC),as well as the capacity of GNSSs to provide UTC time dissemination services are described,leading now to a time transfer accuracy of the order of 1-2 ns.In addition,the fundamental role of atomic clocks in the GNSS positioning is illustrated.The paper presents a review of the current use of GNSS in the international timekeeping system,as well as illustrating the role of GNSS in disseminating time,and use the time and frequency metrology as fundamentals in the navigation service.

Apparent dissociation of photoperiodic time measurement between vernal migration and breeding under dim green light conditions in Gambel＇s white-crowned sparrow Zonotrichia leucophrys gambelii

In seasonally breeding birds, the annual cycle of photoperiod is a principal environmental cue for temporal arrange- ment of different life-history stages, such as migration and breeding. In the past, most research has focused on the mechanisms of photoperiodic control of breeding with less attention paid to migration. In Gambel＇s white-crowned sparrow Zonotrichia leuco- phrys gambelii （GWCS）, photoreceptors for induction of breeding are known to reside in the basal hypothalamus. However, it is unknown whether the sites of photoperiodic reception for vernal migration are the same as those for breeding. Therefore, we hy- pothesized that they may be controlled separately. In this study, we exposed photosensitive GWCSs to low-penetration green light （wavelength at 510 nm） under a regime of 1 lux during the day and 〈0.1 lux at night, and switched the photoperiodic conditions from short day （10 h daytime） to long day （18 h daytime）. The results showed that the experimental birds developed traits associ- ated with vernal migration including mass increase, fat deposition and migratory restlessness behavior when transferred from short day to long day green light cycles, while control birds maintained continuously on short day green light conditions did not ex- press any migration related characteristics. Neither experimental nor control groups showed gonadal recrudescence trader either green light cycles. In support of our hypothesis, we were able to apparently dissociate the photoperiodic responses regulating vernal migra- tion and breeding, which suggests separate mechanisms of photoperiodic time measurement. Such distinct photoperiodic mechanisms may drive the free-tuned temporal arrangement of the two life history stages.

Influence of Precipitation on the Determination of Proper Time for Soil Resistivity Measurement

In order to obtain reliable and effective upland soil resistivity measurements,it is necessary to know how much time after the rain stops is required before making soil resistivity observations so that the influence of precipitation on the measurements can be eliminated.Based on the soil resistivity monitoring data at different depths obtained from the soil conductance automatic monitoring system using the triple-electrode method,and the precipitation data from the synchronous and automatic observing system in Hechuan County of Chongqing,this paper analyzed the effect of rain on the determination of upland soil resistivity measurement time.The results showed that the required interval time between the measurement and the termination of rain should be as follows：if the rainfall was less than 0.1 mm,the interval time was zero;the interval time was 24 h if the precipitation time was less than 1 h or the rainfall was 0.1-2.0 mm;the interval time was 72 h if the precipitation time was 2-10 h or the rainfall was within 2.1-5.0 mm;and the interval time of 72-232 h was observed when the precipitation time was 10-25 h or longer or the rainfall was 5.0-10.1 mm or larger.Relevant observations showed that the above conclusions were on the whole valid for different soil depths.On the other hand,the results indicated that the maximum variance ratio for the influence of precipitation on resistivity measurement was about 28.9%,and the average variance was about 3.9%.Moreover,a preliminary analysis also showed that the precipitation process time might play a more crucial role in the resistivity recovery time than the precipitation amount.It is also found that it is practically better to use the rank correlation method than the numerical correlation analysis method to determine the time break between the stop of rain and the time to carry out the soil resistivity measurement.

Prototype of time digitizing system for BESⅢ endcap TOF upgrade

The prototype of a time digitizing system for the BESⅢ endcap TOF （ETOF） upgrade is introduced in this paper, The ETOF readout electronics has a distributed architecture. Hit signals from the multi-gap resistive plate chamber （MRPC） are signaled as LVDS by front-end electronics （FEE） and are then sent to the back-end time digitizing system via long shield differential twisted pair cables. The ETOF digitizing system consists of two VME crates, each of which contains modules for time digitization, clock, trigger, fast control, etc. The time digitizing module （TDIG） of this prototype can support up to 72 electrical channels for hit information measurement. The fast control （FCTL） module can operate in barrel or endcap mode. The barrel FCTL fans out fast control signals from the trigger system to the endcap FCTLs, merges data from the endcaps and then transfers to the trigger system. Without modifying the barrel TOF （BTOF） structure, this time digitizing architecture benefits from improved ETOF performance without degrading the BTOF performance. Lab experiments show that the time resolution of this digitizing system can be lower than 20 ps, and the data throughput to the DAQ can be about 92 Mbps. Beam experiments show that the total time resolution can be lower than 45 ps.

Delay Time Measurement and Comparison of Protection Strategies with One-Link Failed Domestic Optical Fiber Networks in Taiwan

In this paper, we study the protection strategies of domestic optical fiber networks in Taiwan. Delay time experiment of two one-link failed cases are also reported and compared. We can get best protection strategy and bypass the optical transmission signal at shortest delay time.

Real-time measurement of retardation of eighth-wave plate independent of fast-axis direction

A real-time measurement method for the retardation of an eighth-wave plate is proposed. The collimated laser beam is split using a Clan Taylor polarizer with two side escape windows. The reflected sub-beam is detected using a detector, whereas the transmitted sub-beam passes through the quarter-wave plate and the eighth-wave plate of interest. Then, it is reflected by the mirror and passes reversely through the eighth- and quarter-wave plates. Finally, it is analyzed using the Clan Taylor polarizer and detected using another detector. With two detection signals, the retardation is resolved and found to be independent of the fast-axis direction, initial intensity, and circuit parameters. In the experiment, a crystal quartz sample is measured at different fast-axis angles. The standard deviation of the retardation is 0.9°. The usefulness of the method is verified.