Deciphering the Origins of P1-Induced Power Losses in Cu(In_(x),Ga_(1–x))Se2(CIGS)Modules Through Hyperspectral Luminescence

In this report,we show that hyperspectral high-resolution photoluminescence mapping is a powerful tool for the selection and optimiz1ation of the laser ablation processes used for the patterning interconnections of subcells on Cu(Inx,Ga1-x)Se2(CIGS)modules.In this way,we show that in-depth monitoring of material degradation in the vicinity of the ablation region and the identification of the underlying mechanisms can be accomplished.Specifically,by analyzing the standard P1 patterning line ablated before the CIGS deposition,we reveal an anomalous emission-quenching effect that follows the edge of the molybdenum groove underneath.We further rationalize the origins of this effect by comparing the topography of the P1 edge through a scanning electron microscope(SEM)cross-section,where a reduction of the photoemission cannot be explained by a thickness variation.We also investigate the laser-induced damage on P1 patterning lines performed after the deposition of CIGS.We then document,for the first time,the existence of a short-range damaged area,which is independent of the application of an optical aperture on the laser path.Our findings pave the way for a better understanding of P1-induced power losses and introduce new insights into the improvement of current strategies for industry-relevant module interconnection schemes.

纵向车削有效加工小型精密工件

零件小型化的趋势仍在持续,高科技产品中的零件越来越小,越来越精致。恰恰是在零件用途更加专业化的同时,对精度和耐用性的要求也在不断提高。原来主要用于对精度要求甚高的钟表工业的自动纵向车床,现在也正在被许多其他行业所采用。

Determination of surface color of‘all yellow’mango cultivars using computer vision

Image processing techniques are increasingly applied in sorting applications of agricultural products.This work has assessed the use of image processing for inspecting surface color of two Thai mango cultivars.A computer vision system(CVS)was developed and experiments were conducted to monitor peel color change during the ripening process.Conversion of RGB to CIE-LAB values was done via image processing and prediction models were developed to estimate color parameters from CVS data.Performance evaluations showed insufficient prediction for L values(R2=0.42-0.58),but better results for A and B values(R2=0.90-0.95 and 0.80-0.82,respectively).Compared to the calculated color values hue angle and chroma,a yellowness index computed from intermediate XYZ values was found to be much more adept at accurately predicting peel color from CVS data.Correlations were strong for both cultivars(R2=0.93 for‘Nam Dokmai’and R2=0.95 for‘Maha Chanok’).Results from classification analysis indicated satisfactory results for classifying fruits according to ripeness based on yellowness.Success rates of true positives in the categories unripe,ripe and overripe ranged 72%-92%for‘Nam Dokmai’and 98%-100%for‘Maha Chanok’.Therefore,it was shown that the CVS was capable of producing accurate color values for the two mango cultivars investigated.The findings of this study can be incorporated for development of a robust system for quality prediction and establishment of a CVS for automatic grading and sorting of mangos.

Assessing crop water stress of winter wheat by thermography under different irrigation regimes in North China Plain

Thermal imaging can be used as an indicator of water stress due to the closure of stomatal aperture.In this paper,we analyzed the robustness and sensitivity of thermography of winter wheat in the North China Plain.The seasonal and diurnal variations of Crop Water Stress Index(CWSI)were evaluated.Five treatments were applied by means of irrigation,with plots receiving 100%of ETo(DI),50%(D50),16%(D16)and no irrigation(NI).A high correlation was found between stomatal conductance(gs)and CWSI,depending on the phenological stage of the crop with R2=0.44 at pre-heading stage and R2=0.77 at post-heading stage.In addition,a high correlation between yield and CWSI at different growth stages indicates that thermography can predict yield.Hourly measurements of canopy temperature were taken to study the effect of the time of day on image acquisition and it was found that midday was the most appropriate time.These results should assist in designing precision irrigation scheduling for setting the threshold values.

Monitoring physiological responses to water stress in two maize varieties by infrared thermography

Water stress is one of the main causes of yield reductions in crops,especially in arid and semi-arid regions where the water supply is limited.Plant water status is frequently assessed by pre-dawn leaf water potential(ΨPD)or leaf stomata conductance(gL)measurements,in support of advanced irrigation scheduling.However,both methods are time and labour consuming.A non-invasive approach to water status detection is the use of infrared thermography(IRT).This experiment was conducted in a greenhouse on two potted maize varieties under irrigated and non-irrigated conditions,and the measurements began when the crop had reached its twelve leaf stage.In order to establish the IRT measurements for detecting the water status of maize,an IRT-based crop water stress index(CWSI)was calculated and compared with simultaneously measuredΨPD and gL data.Good correlations were found between CWSI and gL data(r2=0.71&0.81),as well between CWSI andΨPD data(r2=0.53&0.81).These results highlight the appropriateness of infrared thermal imagery to detect and differentiate between the crop water statuses of different genotypes.

Non-invasive water status detection in grapevine(Vitis vinifera L.)by thermography

Grapevines are preferentially grown under mild to moderate water stress conditions to achieve the best compromise between wine quality and quantity.Water status detection for advanced irrigation scheduling is frequently done by predawn leaf water potential(ΨPD)or leaf stomata conductance(gL)measurements.However,these measurements are time and labor consuming.Therefore,the use of infrared thermography(IRT)opens up the possibility to study large population of leaves and to give an overview on the stomatal variation and their dynamics.In the present study IRT was used to identify water stress of potted grapevines.In order to define the sensitivity of IRT measurements to water stress,the IRT-based water status information were compared with simultaneously measuredΨPD and gL data.Correlations between IRT-based CWSI data on the one hand and gL andΨPD on the other showed the potential of IRT for water stress detection.However,the CWSI calculation procedure is laborious and the sensitivity of CWSI for water stress detection still needs to be improved.Therefore,further improvements are necessary in order to apply remote IRT-based systems for irrigation scheduling in the field.

Development of an inflatable solar dryer for improved postharvest handling of paddy rice in humid climates

Rice is the staple food for more than three billion people worldwide.Although considerable progress has been made with respect to improved breeds and production practices,losses during postharvest handling remain considerable.Drying and storage of paddy are two key stages where management can be improved.For rice,grain moisture content of 14%prevents microbiological activity,while a level of about 12%minimizes quality losses over prolonged storage periods.Due to the need for simple and economical technologies,an inflatable solar dryer(ISD)was developed based on adaptations of the Hohenheim-type solar tunnel dryer.To form a drying tunnel,transparent polyethylene(PE)film attaches by zipper to a reinforced black polyvinyl chloride(PVC)film.To reduce heat loss,a flexible multilayer floor was used along the drying area.The tunnel does not need a substructure as it is stabilized adequately from pressure created by two axial flow ventilators.During experiments,paddy was spread on the floor and mixed with a special roller bar.The ISD has been evaluated for paddy in the Philippines during both rainy and dry seasons and was subsequently optimized.Sun drying and shade drying were carried out in parallel for comparison and product was evaluated for moisture content and quality in terms of milling recovery and head rice yield.Moisture content was reduced from 23%to 14%within 26-52 h of continuous operation during the rainy season and 16%to 14%within 4-26 h of drying during the dry season.In both seasons,the final moisture content of 12%was reached after prolonged drying periods.Quality was not found to be affected with respect to drying treatment.The ISD showed advantages over sun drying,despite longer drying periods.

Influence of colour changes and moisture content during banana drying on laser backscattering

Pre-drying treatments are frequently employed to preserve fruit quality.The objective of this research was to monitor colour changes of banana during drying by laser backscattering and to determine the influence of the fruit discolouration on the light distribution into banana tissue.Moreover,to examine the influence of drying on the laser backscatter,the relationship between moisture content and relative laser area of banana slices was analyzed with different degrees of colour degradation.The experiments were conducted at drying air temperature of 63℃with various pre-treatments like chilling,soaking in ascorbic/citric acid and dipping in distilled water.An untreated sample was used as a control.A laser diode emitting at 670 nm with 3 mW power was used as light source.The backscattering relative laser area was used as an indicator for the light absorption into the tissue.The high result achieved on coefficient of determination R^(2)(>0.93)confirmed linear relationship between relative laser area and moisture content.Treatment with ascorbic acid gave the best prediction of the moisture content with the standard error of 5.7 and 8.8 for the estimated intercept and slope.The results showed a significant difference of lightness(L*values)during drying according to the different treatments.As a result,colour degradation did not have a significant influence on the absorption of light at 670 nm wavelength.

Generalized single-layer model for drying kinetics of unpeeled-longan

Dried longan fruit has become an important export product of Thailand.Knowledge about drying kinetics is essential to optimize the drying process.In this study,drying kinetics of unpeeled longan fruits was investigated by varying the parameters as follows:air temperature 50~90℃,relative humidity 4%~20%,air velocity 0.2~0.5 m/s,and size of the fruits.The drying curves of longan fruit,dried in a single layer,were strongly affected by the temperature of the drying air and fruit size but less dependent on relative humidity and velocity of the drying air.Eight single-layer drying models were selected from literature to identify suitable ones for fitting moisture ratio curves to data obtained from the drying experiments.Both,the proportional and exponential coefficient of drying time in the‘Page’model could be given in a generalized function for each of the investigated drying parameters.Moreover,the two coefficients could be correlated to all drying parameters simultaneously.This allowed establishing a generalized‘Page’model for estimating drying curves for any value of temperature,fruit size,relative humidity and air velocity within the range of performed experiments.The analysis also revealed an inner correlation between the two‘Page’coefficients,which opens new doors for further research on the application of the‘Page’model for describing drying processes.