Nondestructive method of measuring soluble solids content (SSC) of citrus fruits was developed using Fourier transform near infrared reflectance (FT-NIR) measurements collected through optics fiber. The models describ...Nondestructive method of measuring soluble solids content (SSC) of citrus fruits was developed using Fourier transform near infrared reflectance (FT-NIR) measurements collected through optics fiber. The models describing the relationship between SSC and the NIR spectra of citrus fruits were developed and evaluated. Different spectra correction algorithms (standard normal variate (SNV), multiplicative signal correction (MSC)) were used in this study. The relationship between laboratory SSC and FT-NIR spectra of citrus fruits was analyzed via principle component regression (PCR) and partial least squares (PLS) re- gression method. Models based on the different spectral ranges were compared in this research. The first derivative and second derivative were applied to all spectra to reduce the effects of sample size, light scattering, instrument noise, etc. Different baseline correction methods were applied to improve the spectral data quality. Among them the second derivative method after baseline correction produced best noise removing capability and yielded optimal calibration models. A total of 170 NIR spectra were acquired; 135 NIR spectra were used to develop the calibration model; the remaining spectra were used to validate the model. The developed PLS model describing the relationship between SSC and NIR reflectance spectra could predict SSC of 35 samples with correlation coefficient of 0.995 and RMSEP of 0.79 °Brix.展开更多
Watermelon is a popular fruit in the world with soluble solids content （SSC） being one of the major characteristics used for assessing its quality. This study was aimed at obtaining a method for nondestructive SSC d...Watermelon is a popular fruit in the world with soluble solids content （SSC） being one of the major characteristics used for assessing its quality. This study was aimed at obtaining a method for nondestructive SSC detection of watermelons by means of visible/near infrared （Vis/NIR） diffuse transmittance technique. Vis/NIR transmittance spectra of intact watermelons were acquired using a low-cost commercially available spectrometer operating over the range 350-1000 nm. Spectra data were analyzed by two multivariate calibration techniques： partial least squares （PLS） and principal component regression （PCR） methods. Two experiments were designed for two varieties of watermelons [Qilin （QL）, Zaochunhongyu （ZC）], which have different skin thickness range and shape dimensions. The influences of different data preprocessing and spectra treatments were also investigated. Performance of different models was assessed in terms of root mean square errors of calibration （RMSEC）, root mean square errors of prediction （RMSEP） and correlation coefficient （r） between the predicted and measured parameter values. Results showed that spectra data preprocessing influenced the performance of the calibration models. The first derivative spectra showed the best results with high correlation coefficient of determination [r=0.918 （QL）; r=0.954 （ZC）], low RMSEP [0.65 °Brix （QL）; 0.58 °Brix （ZC）], low RMSEC [0.48 °Brix （QL）; 0.34°Brix （ZC）] and small difference between the＇RMSEP and the RMSEC by PLS method. The nondestructive Vis/NIR measurements provided good estimates of SSC index of watermelon, and the predicted values were highly correlated with destructively measured values for SSC. The models based on smoothing spectra （Savitzky-Golay filter smoothing method） did not enhance the performance of calibration models obviously. The results indicated the feasibility of Vis/NIR diffuse transmittance spectral analysis for predicting watermelon SSC in a nondestructive way.展开更多
Visible and near infrared spectroscopy is a non-destructive,green,and rapid technology that can be utilized to estimate the components of interest without conditioning it,as compared with classical analytical methods....Visible and near infrared spectroscopy is a non-destructive,green,and rapid technology that can be utilized to estimate the components of interest without conditioning it,as compared with classical analytical methods.The objective of this paper is to compare the performance of artificial neural network(ANN)(a nonlinear model)and principal component regression(PCR)(a linear model)based on visible and shortwave near infrared(VIS-SWNIR)(400-1000 nm)spectra in the non-destructive soluble solids content measurement of an apple.First,we used multiplicative scattering correction to pre-process the spectral data.Second,PCR was applied to estimate the optimal number of input variables.Third,the input variables with an optimal amount were used as the inputs of both multiple linear regression and ANN models.The initial weights and the number of hidden neurons were adjusted to optimize the performance of ANN.Findings suggest that the predictive performance of ANN with two hidden neurons outperforms that of PCR.展开更多
Nondestructive evaluation of melon quality is in great need of comprehensive study.Soluble solids content(SSC)and firmness are the two indicators of melon internal quality that mostly a®ect consumer acceptance.To...Nondestructive evaluation of melon quality is in great need of comprehensive study.Soluble solids content(SSC)and firmness are the two indicators of melon internal quality that mostly a®ect consumer acceptance.To provide guidance for fruit classification,internal quality standards was preliminarily established through sensory test,as:Melon with SSC over 12Brix,firmness 4–5.5 kgf·cm^(-2)2 were considered as satisfactory class sample;and SSC over 10Brix,¯rmness 3.5–6.5 kgf·cm^(-2) as average class sample.The near infrared(NIR)nondestructive detection program was set as spectra collected from the stylar-end,Brix expressed by the average SSC of inner and outer mesocarp,each cultivar of melon was detected with its own optimum integration time,and the second derivative algorithm was used to equalize them.Using wavelength selected by genetic algorithms(GA),a robust SSC model of mix-cultivar melon was established,the root mean standard error of cross-validation(RMSECV)was 0.99 and the ratio performance deviation(RPD)nearly reached 3.0,which almost could meet the accuracy requirement of 1.5Brix.Firmness model of mix-cultivar melon was acceptable but inferior.展开更多
Variable selection is applied widely for visible-near infrared(Vis-NIR)spectroscopy analysis of internal quality in fruits.Different spectral variable selection methods were compared for online quantitative analysis o...Variable selection is applied widely for visible-near infrared(Vis-NIR)spectroscopy analysis of internal quality in fruits.Different spectral variable selection methods were compared for online quantitative analysis of soluble solids content(SSC)in navel oranges.Moving window partial least squares(MW-PLS),Monte Carlo uninformative variables elimination(MC-UVE)and wavelet transform(WT)combined with the MC-UVE method were used to select the spectral variables and develop the calibration models of online analysis of SSC in navel oranges.The performances of these methods were compared for modeling the Vis NIR data sets of navel orange samples.Results show that the WT-MC-UVE methods gave better calibration models with the higher correlation cofficient(r)of 0.89 and lower root mean square error of prediction(RMSEP)of 0.54 at 5 fruits per second.It concluded that Vis NIR spectroscopy coupled with WT-MC-UVE may be a fast and efective tool for online quantitative analysis of SSC in navel oranges.展开更多
The aim of this research was to determine the effect of three organic manures (vermicompost, simple compost, compost with gypsum) with four different levels, as sources of fertilization, and mixed with river sand, thi...The aim of this research was to determine the effect of three organic manures (vermicompost, simple compost, compost with gypsum) with four different levels, as sources of fertilization, and mixed with river sand, this was used as an inert material, on the phenolic content, antioxidant capacity and total soluble solids of bell peppers (Capsicum annuum L.). The 12 mixtures formulated, with eight replications, were distributed in a completely randomized design. Data were statistically analyzed by analysis of variance and means were compared by test Tukey<sub>5%</sub>. All variables were significantly affected (p ≤ 0.001). Fruits with highest phenolic content were developed in the mixtures M2, M5 and M6 with 538.76, 541.54 and 565.04 mg GAE·100 kg<sup>-1</sup> DW, respectively. Antioxidant capacity of fruits was increased with mixtures M2, M5, M6 and M7 with values of 934.48, 942.04, 921.69 and 924.17 μM TEAC·g<sup>-1</sup> DW, respectively. The soluble solids content was higher in mixtures M1 and M2 with values of 4.93 and 4.97 °Brix, respectively. It was concluded that the variables studied were favored when applying, as sources of fertilization, mixtures of these organic manures with river sand, which could represent a suitable alternative for food production with quality nutraceutical.展开更多
The temperature difference of fruit itself will affect its near infrared spectrum and the accuracy of its soluble solids content(SSC)prediction model.To eliminate the influence of apple temperature difference on the S...The temperature difference of fruit itself will affect its near infrared spectrum and the accuracy of its soluble solids content(SSC)prediction model.To eliminate the influence of apple temperature difference on the SSC model,a diffuse transmission dynamic online detection device was used to collect the spectral data of apples at different temperatures,and four methods were used to establish partial least squares correction models:global correction,orthogonal signal processing,generalized least squares weighting and external parameter orthogonal(EPO).The results show that the temperature has a strong influence on the diffuse transmission spectrum of apples.The 20ºC model can get a satisfactory prediction result when the temperature is constant,and there will be great errors when detecting samples at other temperatures.The effect of temperature must be corrected to establish a more general model.These methods all improve the accuracy of the model,with the EPO method giving the best results;the prediction set correlation coefficient is 0.947,the root mean square error of prediction is 0.489%,and the prediction bias is 0.009%.The research results are of great significance to the practical application of SSC prediction of fruits in sorting workshops or orchards.展开更多
Nondestructive determination the internal quality of thick-skin fruits has always been a challenge.In order to investigate the prediction ability of full transmittance mode on the soluble solid content(SSC)in thick-sk...Nondestructive determination the internal quality of thick-skin fruits has always been a challenge.In order to investigate the prediction ability of full transmittance mode on the soluble solid content(SSC)in thick-skin fruits,the full transmittance spectra of citrus were collected using a visible/near infrared(Vis/NIR)portable spectrograph(550–1100 nm).Three obvious absorption peakswere found at 710,810 and 915 nmin the original spectra curve.Four spectral preprocessing methods including Smoothing,multiplicative scatter correction(MSC),standard normal variate(SNV)and first derivativewere employed to improve the quality of the original spectra.Subsequently,the effective wavelengths of SSC were selected from the original and pretreated spectra with the algorithms of successive projections algorithm(SPA),competitive adaptive reweighted sampling(CARS)and genetic algorithm(GA).Finally,the prediction models of SSC were established based on the full wavelengths and effectivewavelengths.Results showed that SPA performed the best performance on eliminating the useless information variable and optimizing the number of effective variables.The optimal predictionmodel was established based on 10 characteristic variables selected from the spectra pretreated by SNV with the algorithmof SPA,with the correlation coefficient,root mean square error,and residual predictive deviation for prediction set being 0.9165,0.5684°Brix and 2.5120,respectively.Overall,the full transmittance mode was feasible to predict the internal quality of thick-skin fruits,like citrus.Additionally,the combination of spectral preprocessing with a variable selection algorithmwas effective for developing the reliable predictionmodel.The conclusions of this study also provide an alternative method for fast and real-time detection of the internal quality of thick-skin fruits using Vis/NIR spectroscopy.展开更多
The near infrared （NIR） spectroscopy technique has been applied in many fields because of its advantages of simple preparation, fast response, and non-destructiveness. We investigated the potential of NIR spectrosco...The near infrared （NIR） spectroscopy technique has been applied in many fields because of its advantages of simple preparation, fast response, and non-destructiveness. We investigated the potential of NIR spectroscopy in diffuse reflectance mode for determining the soluble solid content （SSC） and acidity （pH） of intact loquats. Two cultivars of loquats （Dahongpao and Jiajiaozhong） harvested from two orchards （Tangxi and Chun＇an, Zhejiang, China） were used for the measurement of NIR spectra between 800 and 2500 nm. A total of 400 loquats （100 samples of each cultivar from each orchard） were used in this study. Relationships between NIR spectra and SSC and acidity of loquats were evaluated using partial least square （PLS） method. Spectra preprocessing options included the first and second derivatives, multiple scatter correction （MSC）, and the standard normal variate （SNV）. Three separate spectral windows identified as full NIR （800-2500 nm）, short NIR （800-1100 rim）, and long NIR （1100-2500 nm） were studied in factorial combination with the preprocessing options. The models gave relatively good predictions of the SSC of loquats, with root mean square error of prediction （RMSEP） values of 1.21, 1.00, 0.965, and 1.16 °Brix for Tangxi-Dahongpao, Tangxi-Jiajiaozhong, Chun＇an-Dahongpao, and Chun＇an-Jiajiaozhong, respectively. The acidity prediction was not satisfactory, with the RMSEP of 0.382, 0.194, 0.388, and 0.361 for the above four loquats, respectively. The results indicate that NIR diffuse reflectance spectroscopy can be used to predict the SSC and acidity of loquat fruit.展开更多
In the Retiro, ＂El Lucero＂ county, Maule, VII Region of Chile, an application of a marine algae extract known as Ascophilliurn nodosum, whose commercial name is Ekologik~, was evaluated by applying it to the whole f...In the Retiro, ＂El Lucero＂ county, Maule, VII Region of Chile, an application of a marine algae extract known as Ascophilliurn nodosum, whose commercial name is Ekologik~, was evaluated by applying it to the whole foliage in order to evaluate the impact on total weight, average weight, equatorial diameter and soluble solids in cv. O＇Neal blueberries harvested in a three-year old orchard having a plantation density of 3,333 plants hal. The marine algae extract was applied in three phenologic phases： full bloom, fruit set and fruit color break. Four treatments were conducted： To, application of pure water （without the product）; T1, a 280 mL ha1 dose per application; T2, a 140 mL ha^-1 dose, equivalent to 50% of the treatment dose T1; and T3, a 420 mL ha^-1 dose, equivalent to a 50% extra than the treatment dose T1. The experimental design comprised sutb-sampling blocks with three repetitions of three uniform and healthy plants per treatment. Regarding the total and average fruit weight, they did not show significant statistical differences, but an increase in the average weight of fruits treated with the aforementioned product was observed. For parameters such as equatorial diameter, caliper and soluble solids of harvested fruit, the product caused a statistically significant increase. T3 was found to be the best treatment with a 15% weight, increasing taste, sugar amount, size and weight of the harvested fruits.展开更多
Temperature integration where high day temperatures are compensated by lower night temperatures is one strategy that can be used to reduce energy consumption in greenhouses. Crop tolerance to temperature variation is ...Temperature integration where high day temperatures are compensated by lower night temperatures is one strategy that can be used to reduce energy consumption in greenhouses. Crop tolerance to temperature variation is a prerequisite for using such a strategy. Greenhouse experiments were conducted on tomatoes cvs, Capricia, Mecano and Cederico in order to investigate the effect of different day/night temperature regimes (24/17, 27/14 and 30/11℃) where the same mean temperature was maintained for the production and germination of pollen. In addition, fruit quality as determined by fruit firmness, dry matter content, soluble solids, titratable acids, and pH was examined at harvest and after seven and 14 days of storage. The 30/11℃ treatment significantly increased pollen production and germination compared to the 24/17℃ treatment, while the 27/14℃ treatment was generally in between the other two treatments. Fruits grown at the 27/14℃ treatment were significantly firmer, while fruits grown at 24/17℃ had higher dry matter content, soluble solids, and titratable acids compared to the other treatments. There were significant differences between cultivars with respect to firmness, dry matter, titratable acidity, and pH. The quality of the fruits changed during storage, but the storability of the tomatoes was not affected by preharvest temperature treatments. The overall conclusion was that the 27/14℃ treatment was superior to the other two temperature treatments with respect to the studied parameters.展开更多
Physico-chemical composition of sweet orange （Citrus sinensis L.） cv. blood red was determined in relation to different storage conditions and micronutrients application at department of horticulture, Agricultural U...Physico-chemical composition of sweet orange （Citrus sinensis L.） cv. blood red was determined in relation to different storage conditions and micronutrients application at department of horticulture, Agricultural University Peshawar, Pakistan during 2006-2007 and 2007-2008. The post-harvest quality of sweet orange was evaluated for 60 days storage with 20 days intervals. Fruit were harvested after the foliar application of zinc and boron in two consecutive seasons. The harvested fruits were stored at an ambient temperature （ATS） of 25 ＋ 2 ℃ and at low temperature storage （LTS） of 15 ± 2 ℃ with 60%-70% relative humidity （RH） for 60 days. Sweet oranges stored at LTS maintained better fruit quality than ATS. The foliar application of zinc and boron significantly enhanced fruit juice content, total soluble solids （TSS）, ascorbic acid （AA） and non-reducing sugar （NRS） of fruit. However, fruit juice content, TSS and AA were observed significantly higher, when the fruit was treated with high zinc （1%） and low boron （0.02%）. The percent of weight loss, disease incidence, TSS and reducing sugar （RS） increased with increasing the storage durations. A reduction was noted in fruit juice, AA and NRS with increasing the storage durations.展开更多
The aim of this research was to knowing if it would improve the shelf life of the lemons that were stored in hermetically polystyrene containers closed, as same that were placed in a refrigerated chamber with temperat...The aim of this research was to knowing if it would improve the shelf life of the lemons that were stored in hermetically polystyrene containers closed, as same that were placed in a refrigerated chamber with temperature of 10°C inside, high relative humidity (85%) and renovation of the air by action of the compressor of the chamber. Lemons cv “Lisboa” were cut directly from the orchard and washed with chlorinated water at 150 mg⋅L−1 sodium hypochlorite. The study variables were the color of the epicarp (shell) and the endocarp (pulp), polar and equatorial diameter, firmness of the pulp and total soluble solids concentration (°Brix) in the endocarp. The tone and purity of the yellow color of the shell (epicarp) and pulp or endocarp of the oranges increased significantly within polystyrene containers and, consequently, its quality was preserved and its shelf life was extended to more than 100 days without that they have symptoms of deterioration, by losses polar and equatorial diameter or decrease in total soluble solids. Inside closed containers polystyrene the temperature decreased to 2.0°C in the refrigerated chamber, so that the principle of thermal insulation polystyrene reaffirmed, and its functionality for packaging products, such as fruits, resolve some of their physiological problems themselves, to prolong its shelf life and improve its presentation.展开更多
Mg-6Li and Mg-6Li-1Y （wt.%） alloys were prepared using permanent model casting method, and microstructure and mechanical properties were investigated by means of X-ray diffraction （XRD）, scanning electron microsco...Mg-6Li and Mg-6Li-1Y （wt.%） alloys were prepared using permanent model casting method, and microstructure and mechanical properties were investigated by means of X-ray diffraction （XRD）, scanning electron microscopy （SEM）, optical microscopy （OM）, energy dis-persive spectrometry （EDS）, transmission electron microscopy （TEM）, etc. The results showed that α-Mg and ？-Li phases existed in both al-loys, and there was also Y-enriched phase in Mg-6Li-1Y alloy. The composition of Y-enriched phase was near to the maximal solid solubility of Y in α-Mg phase. The ultimate tensile strength and yield strength of Mg-6Li-1Y alloy were improved to 112 and 107 MPa, respectively. The elongation of Mg-6Li-1Y alloy was greatly enhanced to 32% at room temperature, which was about eight times as great as that of Mg-6Li alloy. The strengthening effects of Mg-6Li-1Y alloy were attributed to the solid solution effect and precipitates both introduced by Y.展开更多
Magnesium matrix composites reinforced with AlN particles were fabricated by the powder metallurgy technique. The evolution of lattice constants and solid solubility levels of Al in α-Mg and the microstructure of Mg-...Magnesium matrix composites reinforced with AlN particles were fabricated by the powder metallurgy technique. The evolution of lattice constants and solid solubility levels of Al in α-Mg and the microstructure of Mg-Al/AlN composites were investigated in the present study. The results showed that the solid solubility of Al in α-Mg reached a relatively high level by the P/M process with a long time of milling. X-ray diffraction showed that the peaks of Mg phase clearly shifted to higher angles. The lattice constants and cell volume decreased significantly compared with those of standard Mg due to a significant amount of Al incorporated into α-Mg in the form of substitutional solid solution. The degree of lattice deformation decreased at a low sintering temperature and increased at higher sintering temperatures due to the presence of AlN. Microstructural characterization of the composites revealed a necklace distribution of AlN particles in the Mg matrix. Heat treatment led to precipitation of Mg17Al12 from the supersaturated α-Mg solid solution. The pre- cipitate exhibited granular and lath-shaped morphologies in Mg matrix and ftocculent precipitation around AlN particles.展开更多
To investigate the influence of high magnetic field (HMF) on the solidification microstructure of Cu-25wt.%Ag alloy, the Cu-25wt.%Ag alloy was prepared under HMF of 12 T, and for comparison, the alloy solidified witho...To investigate the influence of high magnetic field (HMF) on the solidification microstructure of Cu-25wt.%Ag alloy, the Cu-25wt.%Ag alloy was prepared under HMF of 12 T, and for comparison, the alloy solidified without HMF was also fabricated. Macro and microstructures of the alloys were observed using the stereomicroscope, and scanning electron microscope, field emission scanning electron microscopy. The weight percentages of the pro-eutectic and eutectic, Cu phase and Ag phase in eutectic, and precipitates of Ag phase in pro-eutectic were analyzed by using of IPP software. Results show that the morphology of the column dendrites changes into cellular dendrites and the grains are refined under HMF of 12 T. Meanwhile, the thickness of the eutectic wall increases, but the sizes of Cu phase and Ag phase and the eutectic lamellar spacings are decreased. The Ag precipitates in the Cu matrix become coarser and sparser. The weight percentage variation of the phases in the microstructure and the Cu-Ag binary phase diagram reveals that the eutectic point moves to the left of the eutectic point in the equilibrium condition and the supersaturated solid solubility of Ag decreases under HMF.展开更多
Nanocrystalline Cu-5 wt%Cr alloy powders were fabricated by mechanical alloying （MA）, The effects of MA processing parameters on the crystallite size, solid solubility, and microstructures of the Cu- 5 wt%Cr alloys ...Nanocrystalline Cu-5 wt%Cr alloy powders were fabricated by mechanical alloying （MA）, The effects of MA processing parameters on the crystallite size, solid solubility, and microstructures of the Cu- 5 wt%Cr alloys were investigated including type and size distribution of the grinding medium and ball-topowder weight ratio （BPR）. The results show that the crystallites were refined effectively and solid solubility of Cr in Cu was extended when heavier ball and higher BPR were adopted. The maximum solubility is extended up to 5.6 at% （namely 4.6 wt%） Cr in Cu by use of a combination of large and small size WC-Co balls with BPR of 30：1. A Cn-5 wt%Cr supersaturated solid solution alloy bulk is obtained by spark plasma sintering the as-milled powders at 900 ℃ for 5 min.展开更多
The solution behavior of a second element in the primary phase(α(Mg))is important in the design of high-performance alloys.In this work,three sets of features have been collected:a)interaction features of solutes and...The solution behavior of a second element in the primary phase(α(Mg))is important in the design of high-performance alloys.In this work,three sets of features have been collected:a)interaction features of solutes and Mg obtained from first-principles calculation,b)intrinsic physical properties of the pure elements and c)structural features.Based on the maximum solid solubility values,the solution behavior of elements inα(Mg)are classified into four types,e.g.,miscible,soluble,sparingly-soluble and slightly-soluble.The machine learning approach,including random forest and decision tree algorithm methods,is performed and it has been found that four features,e.g.,formation energy,electronegativity,non-bonded atomic radius,and work function,can together determine the classification of the solution behavior of an element inα(Mg).The mathematical correlations,as well as the physical relationships among the selected features have been analyzed.This model can also be applied to other systems following minor modifications of the defined features,if required.展开更多
The splat folis of Al-RE(RE=Y,La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Er and Yb) binary alloys of 0.04—0.06 mm thickness were made by are-melting and hammer-anvil technique,the.cooling rate is in 10~6 K/s order of magnitude.The m...The splat folis of Al-RE(RE=Y,La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Er and Yb) binary alloys of 0.04—0.06 mm thickness were made by are-melting and hammer-anvil technique,the.cooling rate is in 10~6 K/s order of magnitude.The metastable extended solid solubilities of these RE elements have been evaluated by measurements of the lattice spacings of the rapidly solidified(RS)Al-RE alloys,they are 0.4,0.15,0.21,0.21,0.3, 0.5,0.1,0.6,0.65,0.7,0.75,0.2 at.-% for above individual RE clements,respectively.The secondary phase in RS Al-RE alloys were identified to be Al_4RE for alloys containing light RE and Eu elements and Al_3 RE for alloys containing heavy RE and Y elements. Some factors influencing the extension of solid solubility of Al-RE alloy were discussed.展开更多
The microstructures of Mg96.17Zn3.15Y0.50Zr0.18 alloys solidified under 2-6 GPa high pressure were investigated by employing SEM(EDS) and TEM.The strengthening mechanism of experimental alloy solidified under high pre...The microstructures of Mg96.17Zn3.15Y0.50Zr0.18 alloys solidified under 2-6 GPa high pressure were investigated by employing SEM(EDS) and TEM.The strengthening mechanism of experimental alloy solidified under high pressure is also discussed by analyzing the compressive properties and compression fracture morphology.The results show that the microstructure of experimental alloy becomes significantly fine-grained with increasing GPa level high pressure during solidification process,and the secondary dendrite arm spacing reduces from 40 μm at atmospheric pressure to 10 μm at 6 GPa pressure.The morphology of the second phases changes from the net structure by the lamellar-type eutectic structure at atmospheric pressure to discontinuous thin rods or particles at 6 GPa pressure.Besides,the solid solubility of Zn in the Mg matrix is improved with the increase of the solidification pressure.Compared with atmospheric-pressure solidification,high-pressure solidification can improve the strength of the experimental alloy.The compressive stre ngth is improved from 263 to 437 MPa at 6 GPa.The fracture mechanism of the experimental alloy changes from cleavage fracture at atmospheric pressure to quasi-cleavage fracture at high pressure.The main mechanism of the strength improvement of the experimental alloy includes the grain refinement strengthening caused by the refinement of the solidification microstructure,the second phase strengthening caused by the improvement of the morphology and distribution of the second phases,and solid solution strengthening caused by the increase of the solid solubility of Zn in the Mg matrix.展开更多
基金Project supported by New Century Excellent Talents in University(No. NCET-04-0524), and the Research Fund for the Doctoral Pro-gram of Higher Education (No. 20030335060) of China
文摘Nondestructive method of measuring soluble solids content (SSC) of citrus fruits was developed using Fourier transform near infrared reflectance (FT-NIR) measurements collected through optics fiber. The models describing the relationship between SSC and the NIR spectra of citrus fruits were developed and evaluated. Different spectra correction algorithms (standard normal variate (SNV), multiplicative signal correction (MSC)) were used in this study. The relationship between laboratory SSC and FT-NIR spectra of citrus fruits was analyzed via principle component regression (PCR) and partial least squares (PLS) re- gression method. Models based on the different spectral ranges were compared in this research. The first derivative and second derivative were applied to all spectra to reduce the effects of sample size, light scattering, instrument noise, etc. Different baseline correction methods were applied to improve the spectral data quality. Among them the second derivative method after baseline correction produced best noise removing capability and yielded optimal calibration models. A total of 170 NIR spectra were acquired; 135 NIR spectra were used to develop the calibration model; the remaining spectra were used to validate the model. The developed PLS model describing the relationship between SSC and NIR reflectance spectra could predict SSC of 35 samples with correlation coefficient of 0.995 and RMSEP of 0.79 °Brix.
基金Project supported by the National Natural Science Foundation of China (No. 30370371) and Program for New Century Excellent Talents in University (No. NCET-04-0524), China
文摘Watermelon is a popular fruit in the world with soluble solids content （SSC） being one of the major characteristics used for assessing its quality. This study was aimed at obtaining a method for nondestructive SSC detection of watermelons by means of visible/near infrared （Vis/NIR） diffuse transmittance technique. Vis/NIR transmittance spectra of intact watermelons were acquired using a low-cost commercially available spectrometer operating over the range 350-1000 nm. Spectra data were analyzed by two multivariate calibration techniques： partial least squares （PLS） and principal component regression （PCR） methods. Two experiments were designed for two varieties of watermelons [Qilin （QL）, Zaochunhongyu （ZC）], which have different skin thickness range and shape dimensions. The influences of different data preprocessing and spectra treatments were also investigated. Performance of different models was assessed in terms of root mean square errors of calibration （RMSEC）, root mean square errors of prediction （RMSEP） and correlation coefficient （r） between the predicted and measured parameter values. Results showed that spectra data preprocessing influenced the performance of the calibration models. The first derivative spectra showed the best results with high correlation coefficient of determination [r=0.918 （QL）; r=0.954 （ZC）], low RMSEP [0.65 °Brix （QL）; 0.58 °Brix （ZC）], low RMSEC [0.48 °Brix （QL）; 0.34°Brix （ZC）] and small difference between the＇RMSEP and the RMSEC by PLS method. The nondestructive Vis/NIR measurements provided good estimates of SSC index of watermelon, and the predicted values were highly correlated with destructively measured values for SSC. The models based on smoothing spectra （Savitzky-Golay filter smoothing method） did not enhance the performance of calibration models obviously. The results indicated the feasibility of Vis/NIR diffuse transmittance spectral analysis for predicting watermelon SSC in a nondestructive way.
基金Project(No.UTM.J.10.01/13.14/1/127/1 Jld 3(48))supported by the Zamalah Scholarship from the Universiti Teknologi Malaysia
文摘Visible and near infrared spectroscopy is a non-destructive,green,and rapid technology that can be utilized to estimate the components of interest without conditioning it,as compared with classical analytical methods.The objective of this paper is to compare the performance of artificial neural network(ANN)(a nonlinear model)and principal component regression(PCR)(a linear model)based on visible and shortwave near infrared(VIS-SWNIR)(400-1000 nm)spectra in the non-destructive soluble solids content measurement of an apple.First,we used multiplicative scattering correction to pre-process the spectral data.Second,PCR was applied to estimate the optimal number of input variables.Third,the input variables with an optimal amount were used as the inputs of both multiple linear regression and ANN models.The initial weights and the number of hidden neurons were adjusted to optimize the performance of ANN.Findings suggest that the predictive performance of ANN with two hidden neurons outperforms that of PCR.
基金This work was supported by the Special Fund for Agro-scientific Research in the Public Interest (Projected No.201303075)the Earmarked Fund for Modern Agro-industry Technology Research System (Projected No.CARS-26-22)。
文摘Nondestructive evaluation of melon quality is in great need of comprehensive study.Soluble solids content(SSC)and firmness are the two indicators of melon internal quality that mostly a®ect consumer acceptance.To provide guidance for fruit classification,internal quality standards was preliminarily established through sensory test,as:Melon with SSC over 12Brix,firmness 4–5.5 kgf·cm^(-2)2 were considered as satisfactory class sample;and SSC over 10Brix,¯rmness 3.5–6.5 kgf·cm^(-2) as average class sample.The near infrared(NIR)nondestructive detection program was set as spectra collected from the stylar-end,Brix expressed by the average SSC of inner and outer mesocarp,each cultivar of melon was detected with its own optimum integration time,and the second derivative algorithm was used to equalize them.Using wavelength selected by genetic algorithms(GA),a robust SSC model of mix-cultivar melon was established,the root mean standard error of cross-validation(RMSECV)was 0.99 and the ratio performance deviation(RPD)nearly reached 3.0,which almost could meet the accuracy requirement of 1.5Brix.Firmness model of mix-cultivar melon was acceptable but inferior.
基金support provided by National Natural Science Foundation of China (60844007,61178036,21265006)National Science and Technology Support Plan (2008BAD96B04)+1 种基金Special Science and Technology Support Program for Foreign Science and Technology Cooperation Plan (2009BHB15200)Technological expertise and academic leaders training plan of Jiangxi Province (2009DD00700)。
文摘Variable selection is applied widely for visible-near infrared(Vis-NIR)spectroscopy analysis of internal quality in fruits.Different spectral variable selection methods were compared for online quantitative analysis of soluble solids content(SSC)in navel oranges.Moving window partial least squares(MW-PLS),Monte Carlo uninformative variables elimination(MC-UVE)and wavelet transform(WT)combined with the MC-UVE method were used to select the spectral variables and develop the calibration models of online analysis of SSC in navel oranges.The performances of these methods were compared for modeling the Vis NIR data sets of navel orange samples.Results show that the WT-MC-UVE methods gave better calibration models with the higher correlation cofficient(r)of 0.89 and lower root mean square error of prediction(RMSEP)of 0.54 at 5 fruits per second.It concluded that Vis NIR spectroscopy coupled with WT-MC-UVE may be a fast and efective tool for online quantitative analysis of SSC in navel oranges.
文摘The aim of this research was to determine the effect of three organic manures (vermicompost, simple compost, compost with gypsum) with four different levels, as sources of fertilization, and mixed with river sand, this was used as an inert material, on the phenolic content, antioxidant capacity and total soluble solids of bell peppers (Capsicum annuum L.). The 12 mixtures formulated, with eight replications, were distributed in a completely randomized design. Data were statistically analyzed by analysis of variance and means were compared by test Tukey<sub>5%</sub>. All variables were significantly affected (p ≤ 0.001). Fruits with highest phenolic content were developed in the mixtures M2, M5 and M6 with 538.76, 541.54 and 565.04 mg GAE·100 kg<sup>-1</sup> DW, respectively. Antioxidant capacity of fruits was increased with mixtures M2, M5, M6 and M7 with values of 934.48, 942.04, 921.69 and 924.17 μM TEAC·g<sup>-1</sup> DW, respectively. The soluble solids content was higher in mixtures M1 and M2 with values of 4.93 and 4.97 °Brix, respectively. It was concluded that the variables studied were favored when applying, as sources of fertilization, mixtures of these organic manures with river sand, which could represent a suitable alternative for food production with quality nutraceutical.
基金the National Natural Science Foundation of China(No.31760344)the Science and Technology Research Project of Education Department of Jiangxi Province(No.GJJ200615),China。
文摘The temperature difference of fruit itself will affect its near infrared spectrum and the accuracy of its soluble solids content(SSC)prediction model.To eliminate the influence of apple temperature difference on the SSC model,a diffuse transmission dynamic online detection device was used to collect the spectral data of apples at different temperatures,and four methods were used to establish partial least squares correction models:global correction,orthogonal signal processing,generalized least squares weighting and external parameter orthogonal(EPO).The results show that the temperature has a strong influence on the diffuse transmission spectrum of apples.The 20ºC model can get a satisfactory prediction result when the temperature is constant,and there will be great errors when detecting samples at other temperatures.The effect of temperature must be corrected to establish a more general model.These methods all improve the accuracy of the model,with the EPO method giving the best results;the prediction set correlation coefficient is 0.947,the root mean square error of prediction is 0.489%,and the prediction bias is 0.009%.The research results are of great significance to the practical application of SSC prediction of fruits in sorting workshops or orchards.
基金This study was supported by National Key Research and Development Program(2016YFD0200104)Beijing Talents Foundation(2018000021223ZK06)National Natural Science Foundation of China(Grant No.31671927).
文摘Nondestructive determination the internal quality of thick-skin fruits has always been a challenge.In order to investigate the prediction ability of full transmittance mode on the soluble solid content(SSC)in thick-skin fruits,the full transmittance spectra of citrus were collected using a visible/near infrared(Vis/NIR)portable spectrograph(550–1100 nm).Three obvious absorption peakswere found at 710,810 and 915 nmin the original spectra curve.Four spectral preprocessing methods including Smoothing,multiplicative scatter correction(MSC),standard normal variate(SNV)and first derivativewere employed to improve the quality of the original spectra.Subsequently,the effective wavelengths of SSC were selected from the original and pretreated spectra with the algorithms of successive projections algorithm(SPA),competitive adaptive reweighted sampling(CARS)and genetic algorithm(GA).Finally,the prediction models of SSC were established based on the full wavelengths and effectivewavelengths.Results showed that SPA performed the best performance on eliminating the useless information variable and optimizing the number of effective variables.The optimal predictionmodel was established based on 10 characteristic variables selected from the spectra pretreated by SNV with the algorithmof SPA,with the correlation coefficient,root mean square error,and residual predictive deviation for prediction set being 0.9165,0.5684°Brix and 2.5120,respectively.Overall,the full transmittance mode was feasible to predict the internal quality of thick-skin fruits,like citrus.Additionally,the combination of spectral preprocessing with a variable selection algorithmwas effective for developing the reliable predictionmodel.The conclusions of this study also provide an alternative method for fast and real-time detection of the internal quality of thick-skin fruits using Vis/NIR spectroscopy.
基金Project supported by the National Natural Science Foundation of China(No.30825027)the National Key Technology R&D Program of China(No.2006BAD11A12)
文摘The near infrared （NIR） spectroscopy technique has been applied in many fields because of its advantages of simple preparation, fast response, and non-destructiveness. We investigated the potential of NIR spectroscopy in diffuse reflectance mode for determining the soluble solid content （SSC） and acidity （pH） of intact loquats. Two cultivars of loquats （Dahongpao and Jiajiaozhong） harvested from two orchards （Tangxi and Chun＇an, Zhejiang, China） were used for the measurement of NIR spectra between 800 and 2500 nm. A total of 400 loquats （100 samples of each cultivar from each orchard） were used in this study. Relationships between NIR spectra and SSC and acidity of loquats were evaluated using partial least square （PLS） method. Spectra preprocessing options included the first and second derivatives, multiple scatter correction （MSC）, and the standard normal variate （SNV）. Three separate spectral windows identified as full NIR （800-2500 nm）, short NIR （800-1100 rim）, and long NIR （1100-2500 nm） were studied in factorial combination with the preprocessing options. The models gave relatively good predictions of the SSC of loquats, with root mean square error of prediction （RMSEP） values of 1.21, 1.00, 0.965, and 1.16 °Brix for Tangxi-Dahongpao, Tangxi-Jiajiaozhong, Chun＇an-Dahongpao, and Chun＇an-Jiajiaozhong, respectively. The acidity prediction was not satisfactory, with the RMSEP of 0.382, 0.194, 0.388, and 0.361 for the above four loquats, respectively. The results indicate that NIR diffuse reflectance spectroscopy can be used to predict the SSC and acidity of loquat fruit.
文摘In the Retiro, ＂El Lucero＂ county, Maule, VII Region of Chile, an application of a marine algae extract known as Ascophilliurn nodosum, whose commercial name is Ekologik~, was evaluated by applying it to the whole foliage in order to evaluate the impact on total weight, average weight, equatorial diameter and soluble solids in cv. O＇Neal blueberries harvested in a three-year old orchard having a plantation density of 3,333 plants hal. The marine algae extract was applied in three phenologic phases： full bloom, fruit set and fruit color break. Four treatments were conducted： To, application of pure water （without the product）; T1, a 280 mL ha1 dose per application; T2, a 140 mL ha^-1 dose, equivalent to 50% of the treatment dose T1; and T3, a 420 mL ha^-1 dose, equivalent to a 50% extra than the treatment dose T1. The experimental design comprised sutb-sampling blocks with three repetitions of three uniform and healthy plants per treatment. Regarding the total and average fruit weight, they did not show significant statistical differences, but an increase in the average weight of fruits treated with the aforementioned product was observed. For parameters such as equatorial diameter, caliper and soluble solids of harvested fruit, the product caused a statistically significant increase. T3 was found to be the best treatment with a 15% weight, increasing taste, sugar amount, size and weight of the harvested fruits.
文摘Temperature integration where high day temperatures are compensated by lower night temperatures is one strategy that can be used to reduce energy consumption in greenhouses. Crop tolerance to temperature variation is a prerequisite for using such a strategy. Greenhouse experiments were conducted on tomatoes cvs, Capricia, Mecano and Cederico in order to investigate the effect of different day/night temperature regimes (24/17, 27/14 and 30/11℃) where the same mean temperature was maintained for the production and germination of pollen. In addition, fruit quality as determined by fruit firmness, dry matter content, soluble solids, titratable acids, and pH was examined at harvest and after seven and 14 days of storage. The 30/11℃ treatment significantly increased pollen production and germination compared to the 24/17℃ treatment, while the 27/14℃ treatment was generally in between the other two treatments. Fruits grown at the 27/14℃ treatment were significantly firmer, while fruits grown at 24/17℃ had higher dry matter content, soluble solids, and titratable acids compared to the other treatments. There were significant differences between cultivars with respect to firmness, dry matter, titratable acidity, and pH. The quality of the fruits changed during storage, but the storability of the tomatoes was not affected by preharvest temperature treatments. The overall conclusion was that the 27/14℃ treatment was superior to the other two temperature treatments with respect to the studied parameters.
文摘Physico-chemical composition of sweet orange （Citrus sinensis L.） cv. blood red was determined in relation to different storage conditions and micronutrients application at department of horticulture, Agricultural University Peshawar, Pakistan during 2006-2007 and 2007-2008. The post-harvest quality of sweet orange was evaluated for 60 days storage with 20 days intervals. Fruit were harvested after the foliar application of zinc and boron in two consecutive seasons. The harvested fruits were stored at an ambient temperature （ATS） of 25 ＋ 2 ℃ and at low temperature storage （LTS） of 15 ± 2 ℃ with 60%-70% relative humidity （RH） for 60 days. Sweet oranges stored at LTS maintained better fruit quality than ATS. The foliar application of zinc and boron significantly enhanced fruit juice content, total soluble solids （TSS）, ascorbic acid （AA） and non-reducing sugar （NRS） of fruit. However, fruit juice content, TSS and AA were observed significantly higher, when the fruit was treated with high zinc （1%） and low boron （0.02%）. The percent of weight loss, disease incidence, TSS and reducing sugar （RS） increased with increasing the storage durations. A reduction was noted in fruit juice, AA and NRS with increasing the storage durations.
文摘The aim of this research was to knowing if it would improve the shelf life of the lemons that were stored in hermetically polystyrene containers closed, as same that were placed in a refrigerated chamber with temperature of 10°C inside, high relative humidity (85%) and renovation of the air by action of the compressor of the chamber. Lemons cv “Lisboa” were cut directly from the orchard and washed with chlorinated water at 150 mg⋅L−1 sodium hypochlorite. The study variables were the color of the epicarp (shell) and the endocarp (pulp), polar and equatorial diameter, firmness of the pulp and total soluble solids concentration (°Brix) in the endocarp. The tone and purity of the yellow color of the shell (epicarp) and pulp or endocarp of the oranges increased significantly within polystyrene containers and, consequently, its quality was preserved and its shelf life was extended to more than 100 days without that they have symptoms of deterioration, by losses polar and equatorial diameter or decrease in total soluble solids. Inside closed containers polystyrene the temperature decreased to 2.0°C in the refrigerated chamber, so that the principle of thermal insulation polystyrene reaffirmed, and its functionality for packaging products, such as fruits, resolve some of their physiological problems themselves, to prolong its shelf life and improve its presentation.
基金supported by the National Natural Science Foundation of China for Creative Research Group (20921002)the Foundation for Science Program of Changchun City (08YJ09)
文摘Mg-6Li and Mg-6Li-1Y （wt.%） alloys were prepared using permanent model casting method, and microstructure and mechanical properties were investigated by means of X-ray diffraction （XRD）, scanning electron microscopy （SEM）, optical microscopy （OM）, energy dis-persive spectrometry （EDS）, transmission electron microscopy （TEM）, etc. The results showed that α-Mg and ？-Li phases existed in both al-loys, and there was also Y-enriched phase in Mg-6Li-1Y alloy. The composition of Y-enriched phase was near to the maximal solid solubility of Y in α-Mg phase. The ultimate tensile strength and yield strength of Mg-6Li-1Y alloy were improved to 112 and 107 MPa, respectively. The elongation of Mg-6Li-1Y alloy was greatly enhanced to 32% at room temperature, which was about eight times as great as that of Mg-6Li alloy. The strengthening effects of Mg-6Li-1Y alloy were attributed to the solid solution effect and precipitates both introduced by Y.
文摘Magnesium matrix composites reinforced with AlN particles were fabricated by the powder metallurgy technique. The evolution of lattice constants and solid solubility levels of Al in α-Mg and the microstructure of Mg-Al/AlN composites were investigated in the present study. The results showed that the solid solubility of Al in α-Mg reached a relatively high level by the P/M process with a long time of milling. X-ray diffraction showed that the peaks of Mg phase clearly shifted to higher angles. The lattice constants and cell volume decreased significantly compared with those of standard Mg due to a significant amount of Al incorporated into α-Mg in the form of substitutional solid solution. The degree of lattice deformation decreased at a low sintering temperature and increased at higher sintering temperatures due to the presence of AlN. Microstructural characterization of the composites revealed a necklace distribution of AlN particles in the Mg matrix. Heat treatment led to precipitation of Mg17Al12 from the supersaturated α-Mg solid solution. The pre- cipitate exhibited granular and lath-shaped morphologies in Mg matrix and ftocculent precipitation around AlN particles.
基金supported by the National High-Tech Research and Development Program of China(No.2007AA03Z519)the Talents Introduction and Discipline Innovation Program for Higher Education(No.B07015)the Program of "High Grade Numerical Control Machine Tool and Basic Equipment" Major Science and Technology Project(No.2012ZX04010031)
文摘To investigate the influence of high magnetic field (HMF) on the solidification microstructure of Cu-25wt.%Ag alloy, the Cu-25wt.%Ag alloy was prepared under HMF of 12 T, and for comparison, the alloy solidified without HMF was also fabricated. Macro and microstructures of the alloys were observed using the stereomicroscope, and scanning electron microscope, field emission scanning electron microscopy. The weight percentages of the pro-eutectic and eutectic, Cu phase and Ag phase in eutectic, and precipitates of Ag phase in pro-eutectic were analyzed by using of IPP software. Results show that the morphology of the column dendrites changes into cellular dendrites and the grains are refined under HMF of 12 T. Meanwhile, the thickness of the eutectic wall increases, but the sizes of Cu phase and Ag phase and the eutectic lamellar spacings are decreased. The Ag precipitates in the Cu matrix become coarser and sparser. The weight percentage variation of the phases in the microstructure and the Cu-Ag binary phase diagram reveals that the eutectic point moves to the left of the eutectic point in the equilibrium condition and the supersaturated solid solubility of Ag decreases under HMF.
基金Funded by Alstom Grid China Technology Centre and the National Basic Research Program of China (973 Program)(No.2012CB619600)
文摘Nanocrystalline Cu-5 wt%Cr alloy powders were fabricated by mechanical alloying （MA）, The effects of MA processing parameters on the crystallite size, solid solubility, and microstructures of the Cu- 5 wt%Cr alloys were investigated including type and size distribution of the grinding medium and ball-topowder weight ratio （BPR）. The results show that the crystallites were refined effectively and solid solubility of Cr in Cu was extended when heavier ball and higher BPR were adopted. The maximum solubility is extended up to 5.6 at% （namely 4.6 wt%） Cr in Cu by use of a combination of large and small size WC-Co balls with BPR of 30：1. A Cn-5 wt%Cr supersaturated solid solution alloy bulk is obtained by spark plasma sintering the as-milled powders at 900 ℃ for 5 min.
基金the financial support from the National Natural Science Foundation of China(51971044 and U1910213)Natural Science Foundation of Chongqing(cstc2019yszx-jcyj X0004)Fundamental Research Funds for the Central Universities(2020CDJDPT001)。
文摘The solution behavior of a second element in the primary phase(α(Mg))is important in the design of high-performance alloys.In this work,three sets of features have been collected:a)interaction features of solutes and Mg obtained from first-principles calculation,b)intrinsic physical properties of the pure elements and c)structural features.Based on the maximum solid solubility values,the solution behavior of elements inα(Mg)are classified into four types,e.g.,miscible,soluble,sparingly-soluble and slightly-soluble.The machine learning approach,including random forest and decision tree algorithm methods,is performed and it has been found that four features,e.g.,formation energy,electronegativity,non-bonded atomic radius,and work function,can together determine the classification of the solution behavior of an element inα(Mg).The mathematical correlations,as well as the physical relationships among the selected features have been analyzed.This model can also be applied to other systems following minor modifications of the defined features,if required.
文摘The splat folis of Al-RE(RE=Y,La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Er and Yb) binary alloys of 0.04—0.06 mm thickness were made by are-melting and hammer-anvil technique,the.cooling rate is in 10~6 K/s order of magnitude.The metastable extended solid solubilities of these RE elements have been evaluated by measurements of the lattice spacings of the rapidly solidified(RS)Al-RE alloys,they are 0.4,0.15,0.21,0.21,0.3, 0.5,0.1,0.6,0.65,0.7,0.75,0.2 at.-% for above individual RE clements,respectively.The secondary phase in RS Al-RE alloys were identified to be Al_4RE for alloys containing light RE and Eu elements and Al_3 RE for alloys containing heavy RE and Y elements. Some factors influencing the extension of solid solubility of Al-RE alloy were discussed.
基金the National Natural Science Foundation of China(51675092,51775099)the Natural Science Foundation of Hebei Province(E2018501032,E2018501033)。
文摘The microstructures of Mg96.17Zn3.15Y0.50Zr0.18 alloys solidified under 2-6 GPa high pressure were investigated by employing SEM(EDS) and TEM.The strengthening mechanism of experimental alloy solidified under high pressure is also discussed by analyzing the compressive properties and compression fracture morphology.The results show that the microstructure of experimental alloy becomes significantly fine-grained with increasing GPa level high pressure during solidification process,and the secondary dendrite arm spacing reduces from 40 μm at atmospheric pressure to 10 μm at 6 GPa pressure.The morphology of the second phases changes from the net structure by the lamellar-type eutectic structure at atmospheric pressure to discontinuous thin rods or particles at 6 GPa pressure.Besides,the solid solubility of Zn in the Mg matrix is improved with the increase of the solidification pressure.Compared with atmospheric-pressure solidification,high-pressure solidification can improve the strength of the experimental alloy.The compressive stre ngth is improved from 263 to 437 MPa at 6 GPa.The fracture mechanism of the experimental alloy changes from cleavage fracture at atmospheric pressure to quasi-cleavage fracture at high pressure.The main mechanism of the strength improvement of the experimental alloy includes the grain refinement strengthening caused by the refinement of the solidification microstructure,the second phase strengthening caused by the improvement of the morphology and distribution of the second phases,and solid solution strengthening caused by the increase of the solid solubility of Zn in the Mg matrix.
