The influence of light and temperature conditions inside solar greenhouse of winter-spring and autumn-winter crop in northern China on uptake and distribution of nitrogen. phosphorus and potassium of cucumber was stud...The influence of light and temperature conditions inside solar greenhouse of winter-spring and autumn-winter crop in northern China on uptake and distribution of nitrogen. phosphorus and potassium of cucumber was studied. The results showed that plant root development and uptake and distribution of N, P and K benefited more from inside light and temperature changes in winter-spring crop. Root volume and root activity increased more rapidly in winter-spring than in autumn-winter. Uptake of total N, P2O5 and K2O increased with plant development in winter-spring, and declined in autumn-winter crop. Distribution of total N, P2O5 and K2O at different part of cucumber at fruit bearing stage was significantly influenced by inside light and temperature of solar greenhouse. Total N, P2O5 and K2O were mainly distributed to leaves and stems at early stage, and increasingly to fruits after fruit bearing.展开更多
In order to calculate the pressure distribution of radial grooved thrust bearing, analytical and numerical methods were applied respectively. Grooved region and land region were linked by u- sing the mass conservation...In order to calculate the pressure distribution of radial grooved thrust bearing, analytical and numerical methods were applied respectively. Grooved region and land region were linked by u- sing the mass conservations principle at the groove/land boundary in each method. The block-weight approach was implemented to deal with the non-coincidence of mesh and radial groove pattern in nu- merical method. It was observed that the numerical solutions had higher precision as mesh number exceed 70 x 70, and the relaxation iteration of differential scheme presented the fastest convergence speed when relaxation factor was close to 1.94.展开更多
In this paper, vibration analysis of irregular-closed-cell foam plates is per- formed. A cell volume distribution coefficient is introduced to modify the original Gibson- Ashby equations of effective Young's modulus ...In this paper, vibration analysis of irregular-closed-cell foam plates is per- formed. A cell volume distribution coefficient is introduced to modify the original Gibson- Ashby equations of effective Young's modulus of foam materials. A Burr distribution is imported to describe the cell volume distribution situation. Three Burr distribution pa- rameters are obtained and related to the cell volume range and the diversity. Based on the plate theory and the effective modulus theory, the natural frequency of foam plates is calculated with the change of the cell volume distribution parameters. The relationship between the frequencies and the cell volumes are derived. The scale factor of the average cell size is introduced and proved to be an important factor to the performance of the foam plate. The result is shown by the existing theory of size effects. It is determined that the cell volume distribution has an impact on the natural frequency of the plate structure based on the cell volume range, the diversity, and the average size, and the impact can lead to optimization of the synthesis procedure.展开更多
Using the Feynman's path integral with topological constraints arising from the presence of one singular line, we find the homotopic probability distribution PnL for the winding number n and the partition function...Using the Feynman's path integral with topological constraints arising from the presence of one singular line, we find the homotopic probability distribution PnL for the winding number n and the partition function PL of the entangled system around a ribbon segment chain. We find that when the width of the ribbon segment chain 2a increases,the partition function exponentially decreases, whereas the free energy increases an amount, which is proportional to the square of the width. When the width tends to zero we obtain the same results as those of a single chain with one singular point.展开更多
The formation mechanism of an EFP(explosively formed projectile)using a double curvature liner under the overpressure effect generated by a regular oblique reflection was investigated in this paper.Based on the detona...The formation mechanism of an EFP(explosively formed projectile)using a double curvature liner under the overpressure effect generated by a regular oblique reflection was investigated in this paper.Based on the detonation wave propagation theory,the change of the incident angle of the detonation wave collision at different positions and the distribution area of the overpressure on the surface of the liner were calculated.Three dimensional numerical simulations of the formation process of the EFP with tail.as well as the ability to penetrate 45#steel were performed using LS-DYNA software,and the EFP ve locity,the penetration ability,and the forming were assessed via experiments and x_ray photographs.The experimental results coincides with those of the simulations.Results indicate that the collision of the detonation wave was controlled to be a regular oblique reflection acting on the liner by setting the di-mensions of the unit charge and maintai ning the pressure at the collision point region at more than 2.4 times the CJ detonation when the incident angle approached the cnitical angle.The distance from the liner midline to the boundary of the area within which the pressure ratio of the regular oblique reflection pressure to the qJ detonation pressure was greater than 2.5,2,and 15was approximately 0.66 mm,132 mm,and 3.3 mm,respectively.Itis noted that pressure gradient caused the liner to turn inside out in the middle to form the head of the EFP and close the two tails of the EFP at approximately 120μs.The penetration depth of the EFP into a 45#steel target exceeded 30 mm,and there was radial expansion between the head and tail of the EFP,increasing the penetration resistance of the EFP.Therefore,the structural size of the unit charge and the liner can be further optimized to reduce resist ance to increase the penetration ability of the EFP.展开更多
Antarctic krill (Euphausia superba) were collected from the Prydz Bay region during the austral summer of 1999/2000. The sample - collection was made at 15 sites in 3 longitudinal transects. Although krill were encoun...Antarctic krill (Euphausia superba) were collected from the Prydz Bay region during the austral summer of 1999/2000. The sample - collection was made at 15 sites in 3 longitudinal transects. Although krill were encountered at 14 sites, the abundance was comparatively low in general. The main component of the krill population was of post -larval stages. The mean numerical and weight density of krill integrated for all sampling stations in the survey area were 16. 17 ind. 1000 m -3and 12.02 g 1000 m -3 , respectively. In the survey area, stations with larger krill density are mainly located in the slope zone, except that the largest sample was collected in the open sea zone. No krill occurred in the only station of the shelf zone during our investigation. Krill collected from the slope zone were under better growth condition than those from the open sea zone, but when the survey area is considered as a whole, the growth condition is normal. The results of the comprehensive analysis of the environmental factors show that the three large sample stations seem to be related with the cold water mass at 75 m depth and the confluence area between the high and low Chla centers at the depth of 25 m.展开更多
The global wall shear stress measurement tech- nique using shear-sensitive liquid crystal (SSLC) is extended to wind tunnel measurements. Simple and common every- day equipment is used in the measurement; in particu...The global wall shear stress measurement tech- nique using shear-sensitive liquid crystal (SSLC) is extended to wind tunnel measurements. Simple and common every- day equipment is used in the measurement; in particular a tungsten-halogen light bulb provides illumination and a saturation of SSLC coating color change with time is found. Spatial wall shear stress distributions of several typical flows are obtained using this technique, including wall-jet flow, vortex flow generated by a delta wing and junction flow behind a thin cylinder, although the magnitudes are not fully calibrated. The results demonstrate that SSLC technique can be extended to wind tunnel measurements with no complicated facilities used.展开更多
This paper presents an approach based on field data to model the spatial distribution of the site productivity index (SPI) of the diverse forest types in Jalisco, Mexico and the response in SPI to site and cli-matic...This paper presents an approach based on field data to model the spatial distribution of the site productivity index (SPI) of the diverse forest types in Jalisco, Mexico and the response in SPI to site and cli-matic conditions. A linear regression model was constructed to test the hypothesis that site and climate variables can be used to predict the SPI of the major forest types in Jalisco. SPI varied significantly with topog-raphy (elevation, aspect and slope), soil attributes (pH, sand and silt), climate (temperature and precipitation zones) and forest type. The most important variable in the model was forest type, which accounted for 35% of the variability in SPI. Temperature and precipitation accounted for 8 to 9% of the variability in SPI while the soil attributes accounted for less than 4% of the variability observed in SPI. No significant differences were detected between the observed and predicted SPI for the individual forest types. The linear regression model was used to develop maps of the spatial variability in predicted SPI for the individual forest types in the state. The spatial site productivity models developed in this study provides a basis for understanding the complex relationship that exists between forest productivity and site and climatic conditions in the state. Findings of this study will assist resource managers in making cost-effective decisions about the management of individual forest types in the state of Jalisco, Mexico.展开更多
Cyber losses in terms of number of records breached under cyber incidents commonly feature a significant portion of zeros, specific characteristics of mid-range losses and large losses, which make it hard to model the...Cyber losses in terms of number of records breached under cyber incidents commonly feature a significant portion of zeros, specific characteristics of mid-range losses and large losses, which make it hard to model the whole range of the losses using a standard loss distribution. We tackle this modeling problem by proposing a three-component spliced regression model that can simultaneously model zeros, moderate and large losses and consider heterogeneous effects in mixture components. To apply our proposed model to Privacy Right Clearinghouse (PRC) data breach chronology, we segment geographical groups using unsupervised cluster analysis, and utilize a covariate-dependent probability to model zero losses, finite mixture distributions for moderate body and an extreme value distribution for large losses capturing the heavy-tailed nature of the loss data. Parameters and coefficients are estimated using the Expectation-Maximization (EM) algorithm. Combining with our frequency model (generalized linear mixed model) for data breaches, aggregate loss distributions are investigated and applications on cyber insurance pricing and risk management are discussed.展开更多
According to the existing research, the fault section location and fault location of passive distribution network and active distribution network are reviewed. Among them, fault location of passive distribution networ...According to the existing research, the fault section location and fault location of passive distribution network and active distribution network are reviewed. Among them, fault location of passive distribution network mainly introduces fault segment location based on transient state and steady state quantity and fault location based on transient quantity. The active distribution network mainly introduces the fault segment location based on the current amount and the switching capacity based on the distribution network topology. On this basis, the difficulties of fault location in the distribution network at present are analyzed, and the future development is prospected.展开更多
To improve the microcrystalline silicon thin film deposition in quality and to increase its microcrystalline silicon content,we numerically investigated the characteristics of homogeneous discharges in hydrogen dilute...To improve the microcrystalline silicon thin film deposition in quality and to increase its microcrystalline silicon content,we numerically investigated the characteristics of homogeneous discharges in hydrogen diluted silane and argon mixed gases at atmospheric pressure using a two-dimensional fluid model.The model takes into account the primary processes of excitation and ionization,sixteen reactions of radicals with radicals in silane/hydrogen/argon discharges,so this model can adequately describe the discharge plasma.The effects of very high frequency(VHF)excitation on the electron density in such discharges are analyzed.The simulation results show that the electron density does not linearly vary with the excitation frequency within from 90150 MHz.he maximum value occurs at an appropriate excitation frequency i.e.the transition frequency.Increasof the excitation frequency would effectively increase the electron density before the transition frequency,but decreases the density afterwards.is.Moreover,the densities of involved particle species,including H2+,H,Ar*,Ar+,SiH3+,SiH3,SiH3,SiH2are closely interrelated.展开更多
In order to discuss the mechanisms of permanent fixation of wood compression set , compressed wood of Chinese fir (Cunninghamia lanceolata) was irradiated by gamma rays from 60 Co. The irradiation doses wer...In order to discuss the mechanisms of permanent fixation of wood compression set , compressed wood of Chinese fir (Cunninghamia lanceolata) was irradiated by gamma rays from 60 Co. The irradiation doses were 0 (for match specim ens), 10 3, 5×10 3, 10 4, 5×10 4, 10 5, 5×10 5, 10 6, 5×10 6 Gy, res pectively. Then the weight loss, the equilibrium moisture content (EMC), the rec overy of wood compression set after adsorption (RSA) and the recovery after imme rsion in water (RSW), as well as the creep behaviour under a dry specimen condit ion and under an adsorption and subsequent desorption condition were measured an d discussed. This research proves that the doses of gamma irradiation have great effect on weight loss, EMC, RSA, RSW of irradiated compressed wood of Chinese f ir. The weight loss and the EMC increase, the RSA and the RSW fall drastically w hen the irradiation doses exceed 10 6 Gy. Both the instantaneous compliance and the creep compliance of the irradiated specimens under the two measurement cond itions show the general trend of increase with the increase of gamma irradiation doses. It can be deduced that decomposition or decrystallization reactions happ en in the wood cell wall at high gamma irradiation doses, especially at doses of around 5×10 6 Gy. In addition, this research proves that decomposition of mai n components of cell wall of compressed wood will lead to fixation of compressio n set of wood to a certain degree.展开更多
[Objective] This research aimed to establish an inductively coupled plasma mass spectrometry (ICP-MS) method for determination of five kinds of heavy metals (Pb, Cd, Cu, As and Hg) in Dendrobium candidium Wall. ex...[Objective] This research aimed to establish an inductively coupled plasma mass spectrometry (ICP-MS) method for determination of five kinds of heavy metals (Pb, Cd, Cu, As and Hg) in Dendrobium candidium Wall. ex Lindl. [Method] The samples were digested in HNO3-H202 acids system by closed vessel microwave di- gestion. At the same time, internal standard was added to avoid the matrix effect. [Result] The five kinds of heavy meals all showed good linear relationships, and the correlation coefficients ranged from 0.998 2 to 0.999 9. The detection limits of the five kinds of heavy metals were in the range of 0.008-0.750 μg/L, while the stan- dard recovery rates were in the range of 90.4%-96.9%. The relative standard devi- ations ranged from 1.6% to 8.2%. The heavy metals in the Ginseng and Astragalus national standard samples were determined by the established ICP-MS method, and the results were in conformity with the standard values. [Conclusion] The established method has simple and convenient operation and accurate and reliable results, and it meets the requirements by determination of heavy metals in Dendrobium candididium Wall. ex Lindl.展开更多
This standard operating procedure stipulated the natural condition of pro- ducing area, cultivation technique, disease and pest control, harvest, quality stan- dard, packaging, transportation and storage of H. cordata...This standard operating procedure stipulated the natural condition of pro- ducing area, cultivation technique, disease and pest control, harvest, quality stan- dard, packaging, transportation and storage of H. cordata, in order to provide a ba- sis for the standard cultivation of H. cordata.展开更多
[Objective] The Cu-tolerance and Cu enrichment capacity of TLSB2-K were investigated. [Method] The previously isolated TLSB2-K strain was identified though morphological observation, gram staining and 16S rDNA sequenc...[Objective] The Cu-tolerance and Cu enrichment capacity of TLSB2-K were investigated. [Method] The previously isolated TLSB2-K strain was identified though morphological observation, gram staining and 16S rDNA sequence alignment. In ad- dition, the effects of temperature, pH and osmotic pressure on the growth of strain were also investigated by using shaking culture. The Cu-tolerance and Cu enrich- ment capacity of TLSB2-K strain under Cu stress were also studied. [Result] The results showed TLSB2-K belongs to Bacillus spp., and its optimum growth conditions were as follows: temperature, 27 ~C; pH, 7.0; osmotic pressure, 1.1% NaCI. When the Cu concentration ranged from 100 mg/L to 500 mg/L, the strain grew well; when the Cu concentration ranged from 100 mg/L to 400 mg/L, the Cu content in bacteria was increased with the increase of Cu concentration; when the Cu con- centration was 400 mg/L and the incubation time was 30 h, the Cu content in bac- teria reached the peak (2 250 mg/kg); the highest tolerant concentration was 700 mg/L. [Conclusion] TLSB2-K strain had relatively high Cu tolerance and Cu enrich- ment capacity. They had important theoretical research and engineering application values.展开更多
In the research, changes of apple chemistry, and molecule, under stresses, are n terms of morphology, physiology, bio- illustrated and research and identifica- tion methods of apple resistance are explored involving ...In the research, changes of apple chemistry, and molecule, under stresses, are n terms of morphology, physiology, bio- illustrated and research and identifica- tion methods of apple resistance are explored involving drought-resistance, flood-re- sistance, salt-stress resistance, cold-hardiness and heat-resistance. In addition prospects of apple resistance research are proposed, as well.展开更多
[Objective] This study aimed to investigate the growth and development and dry matter production and allocation of greenhouse tomato in North China. [Method] With tomato cultivar 'Jinguo No.l' as the experimental ma...[Objective] This study aimed to investigate the growth and development and dry matter production and allocation of greenhouse tomato in North China. [Method] With tomato cultivar 'Jinguo No.l' as the experimental material, the ex- periments were conducted in a solar greenhouse located in Taigu, Shanxi (37o25' N, 112o25' E) from March to July, in 2014 and 2015. [Result] The plant height, leaf number, leaf area and dry matter production of greenhouse tomato increased lin- early with the increased days after transplantation, and their growth rates were 2.74 cm/d, 0.32 leaf/d, 70 cm2/d and 9.4 g/(m2.d), respectively. The fruit dry weight also showed a linear relationship with the plant dry weight. After fruit setting, the fruit dry weight was increased by about 0.69 g when the plant dry weight was increased by 1 g. The allocation proportions of dry matter in tomato roots, stems and leaves de- clined significantly from plant flowering to fruiting, while the proportion of fruit dry weight in plant dry weight increased significantly, exceeding 60%. There was a strong linear relationship between dry matter production of tomato and effective cu- mulative temperature (sum of temperature higher than 10 ^(3) in the solar green- house, and the dry matter production was increased by about 0.73 g/m2 when the effective cumulative temperature was increased by one unit. The dry matter produc- tion of tomato plant also showed a strong linear relationship with photosynthetic ac- tive radiation (PAR) in the greenhouse, and about 3.4 g of dry matter was synthe- sized per unit (M J) of PAR. [Conclusion] Extending the growing period and improv- ing the temperature and light conditions could increase the dry matter production of tomato.展开更多
[Objective] The aim of this study was to understand the difference of N fertilizer requirement between hybrid rapeseed and conventional rapeseed. [Method] Two hybrid cultivars, ZY5628 and ZY7819, and the conventional ...[Objective] The aim of this study was to understand the difference of N fertilizer requirement between hybrid rapeseed and conventional rapeseed. [Method] Two hybrid cultivars, ZY5628 and ZY7819, and the conventional cultivar ZS10, were compared through two field experiments. In Experiment 1, seed yield and optimum N application rate were assessed in the field with five N application treatments. In Expedment 2, N was applied uniformly at 180 kg/hm2, and plant biomass and N accumulation were measured at several developmental stages, while N use efficien- cy was calculated for rape at maturity. [Results] The experiment 1 results showed that seed yields of ZY5628 and ZY7819 were both significantly higher than that of ZS10, and compared to ZS10, optimum yield (plateau yield) was higher by 18.7% and 20.2%, while the recommended N application rate was lower by 9.5% and 9.6% for ZY5628 and ZY7819, respectively. The experiment 2 results showed that during vegetative development, all three cultivars exhibited similar accumulations of plant biomass and N, but through flowering and maturity ZY5628 and ZY7819 pro- duced more biomass, acquired more N, and utilized acquired N more efficiently to- wards seed production than ZS10. [Conclusion] With equivalent inputs, the hybrid rapeseed cultivars ZY5628 and ZY7819 tested herein yield more seed with higher N use efficiency than the conventional rapeseed ZS10. This information will be valu- able for growers seeking to improve efficiency while reducing costs of rape production in China.展开更多
基金the National Natural Science Foundation of China (39830230) Beijing Natural Science Foundation (6011002).
文摘The influence of light and temperature conditions inside solar greenhouse of winter-spring and autumn-winter crop in northern China on uptake and distribution of nitrogen. phosphorus and potassium of cucumber was studied. The results showed that plant root development and uptake and distribution of N, P and K benefited more from inside light and temperature changes in winter-spring crop. Root volume and root activity increased more rapidly in winter-spring than in autumn-winter. Uptake of total N, P2O5 and K2O increased with plant development in winter-spring, and declined in autumn-winter crop. Distribution of total N, P2O5 and K2O at different part of cucumber at fruit bearing stage was significantly influenced by inside light and temperature of solar greenhouse. Total N, P2O5 and K2O were mainly distributed to leaves and stems at early stage, and increasingly to fruits after fruit bearing.
基金Supported by the Ministerial Level Foundation(2220060029)
文摘In order to calculate the pressure distribution of radial grooved thrust bearing, analytical and numerical methods were applied respectively. Grooved region and land region were linked by u- sing the mass conservations principle at the groove/land boundary in each method. The block-weight approach was implemented to deal with the non-coincidence of mesh and radial groove pattern in nu- merical method. It was observed that the numerical solutions had higher precision as mesh number exceed 70 x 70, and the relaxation iteration of differential scheme presented the fastest convergence speed when relaxation factor was close to 1.94.
基金Project supported by the National Natural Science Foundation of China(No.90916007)
文摘In this paper, vibration analysis of irregular-closed-cell foam plates is per- formed. A cell volume distribution coefficient is introduced to modify the original Gibson- Ashby equations of effective Young's modulus of foam materials. A Burr distribution is imported to describe the cell volume distribution situation. Three Burr distribution pa- rameters are obtained and related to the cell volume range and the diversity. Based on the plate theory and the effective modulus theory, the natural frequency of foam plates is calculated with the change of the cell volume distribution parameters. The relationship between the frequencies and the cell volumes are derived. The scale factor of the average cell size is introduced and proved to be an important factor to the performance of the foam plate. The result is shown by the existing theory of size effects. It is determined that the cell volume distribution has an impact on the natural frequency of the plate structure based on the cell volume range, the diversity, and the average size, and the impact can lead to optimization of the synthesis procedure.
文摘Using the Feynman's path integral with topological constraints arising from the presence of one singular line, we find the homotopic probability distribution PnL for the winding number n and the partition function PL of the entangled system around a ribbon segment chain. We find that when the width of the ribbon segment chain 2a increases,the partition function exponentially decreases, whereas the free energy increases an amount, which is proportional to the square of the width. When the width tends to zero we obtain the same results as those of a single chain with one singular point.
基金The work presented in this paper has been supported by the science foundation(YT20-01-02)of Nanjing Vocational University of Industry Technology and the National Science Foundation of China under NO.11802141.
文摘The formation mechanism of an EFP(explosively formed projectile)using a double curvature liner under the overpressure effect generated by a regular oblique reflection was investigated in this paper.Based on the detonation wave propagation theory,the change of the incident angle of the detonation wave collision at different positions and the distribution area of the overpressure on the surface of the liner were calculated.Three dimensional numerical simulations of the formation process of the EFP with tail.as well as the ability to penetrate 45#steel were performed using LS-DYNA software,and the EFP ve locity,the penetration ability,and the forming were assessed via experiments and x_ray photographs.The experimental results coincides with those of the simulations.Results indicate that the collision of the detonation wave was controlled to be a regular oblique reflection acting on the liner by setting the di-mensions of the unit charge and maintai ning the pressure at the collision point region at more than 2.4 times the CJ detonation when the incident angle approached the cnitical angle.The distance from the liner midline to the boundary of the area within which the pressure ratio of the regular oblique reflection pressure to the qJ detonation pressure was greater than 2.5,2,and 15was approximately 0.66 mm,132 mm,and 3.3 mm,respectively.Itis noted that pressure gradient caused the liner to turn inside out in the middle to form the head of the EFP and close the two tails of the EFP at approximately 120μs.The penetration depth of the EFP into a 45#steel target exceeded 30 mm,and there was radial expansion between the head and tail of the EFP,increasing the penetration resistance of the EFP.Therefore,the structural size of the unit charge and the liner can be further optimized to reduce resist ance to increase the penetration ability of the EFP.
基金This study was supported by the CAS know ledge innov ation program KZCX2-303.
文摘Antarctic krill (Euphausia superba) were collected from the Prydz Bay region during the austral summer of 1999/2000. The sample - collection was made at 15 sites in 3 longitudinal transects. Although krill were encountered at 14 sites, the abundance was comparatively low in general. The main component of the krill population was of post -larval stages. The mean numerical and weight density of krill integrated for all sampling stations in the survey area were 16. 17 ind. 1000 m -3and 12.02 g 1000 m -3 , respectively. In the survey area, stations with larger krill density are mainly located in the slope zone, except that the largest sample was collected in the open sea zone. No krill occurred in the only station of the shelf zone during our investigation. Krill collected from the slope zone were under better growth condition than those from the open sea zone, but when the survey area is considered as a whole, the growth condition is normal. The results of the comprehensive analysis of the environmental factors show that the three large sample stations seem to be related with the cold water mass at 75 m depth and the confluence area between the high and low Chla centers at the depth of 25 m.
基金the Doctorate Creation Foundation of Northwestern Polytechnical University (CX200902)
文摘The global wall shear stress measurement tech- nique using shear-sensitive liquid crystal (SSLC) is extended to wind tunnel measurements. Simple and common every- day equipment is used in the measurement; in particular a tungsten-halogen light bulb provides illumination and a saturation of SSLC coating color change with time is found. Spatial wall shear stress distributions of several typical flows are obtained using this technique, including wall-jet flow, vortex flow generated by a delta wing and junction flow behind a thin cylinder, although the magnitudes are not fully calibrated. The results demonstrate that SSLC technique can be extended to wind tunnel measurements with no complicated facilities used.
文摘This paper presents an approach based on field data to model the spatial distribution of the site productivity index (SPI) of the diverse forest types in Jalisco, Mexico and the response in SPI to site and cli-matic conditions. A linear regression model was constructed to test the hypothesis that site and climate variables can be used to predict the SPI of the major forest types in Jalisco. SPI varied significantly with topog-raphy (elevation, aspect and slope), soil attributes (pH, sand and silt), climate (temperature and precipitation zones) and forest type. The most important variable in the model was forest type, which accounted for 35% of the variability in SPI. Temperature and precipitation accounted for 8 to 9% of the variability in SPI while the soil attributes accounted for less than 4% of the variability observed in SPI. No significant differences were detected between the observed and predicted SPI for the individual forest types. The linear regression model was used to develop maps of the spatial variability in predicted SPI for the individual forest types in the state. The spatial site productivity models developed in this study provides a basis for understanding the complex relationship that exists between forest productivity and site and climatic conditions in the state. Findings of this study will assist resource managers in making cost-effective decisions about the management of individual forest types in the state of Jalisco, Mexico.
文摘Cyber losses in terms of number of records breached under cyber incidents commonly feature a significant portion of zeros, specific characteristics of mid-range losses and large losses, which make it hard to model the whole range of the losses using a standard loss distribution. We tackle this modeling problem by proposing a three-component spliced regression model that can simultaneously model zeros, moderate and large losses and consider heterogeneous effects in mixture components. To apply our proposed model to Privacy Right Clearinghouse (PRC) data breach chronology, we segment geographical groups using unsupervised cluster analysis, and utilize a covariate-dependent probability to model zero losses, finite mixture distributions for moderate body and an extreme value distribution for large losses capturing the heavy-tailed nature of the loss data. Parameters and coefficients are estimated using the Expectation-Maximization (EM) algorithm. Combining with our frequency model (generalized linear mixed model) for data breaches, aggregate loss distributions are investigated and applications on cyber insurance pricing and risk management are discussed.
文摘According to the existing research, the fault section location and fault location of passive distribution network and active distribution network are reviewed. Among them, fault location of passive distribution network mainly introduces fault segment location based on transient state and steady state quantity and fault location based on transient quantity. The active distribution network mainly introduces the fault segment location based on the current amount and the switching capacity based on the distribution network topology. On this basis, the difficulties of fault location in the distribution network at present are analyzed, and the future development is prospected.
基金Project supported by Liaoning Provincial Natural Science Foundation of China (201202037).
文摘To improve the microcrystalline silicon thin film deposition in quality and to increase its microcrystalline silicon content,we numerically investigated the characteristics of homogeneous discharges in hydrogen diluted silane and argon mixed gases at atmospheric pressure using a two-dimensional fluid model.The model takes into account the primary processes of excitation and ionization,sixteen reactions of radicals with radicals in silane/hydrogen/argon discharges,so this model can adequately describe the discharge plasma.The effects of very high frequency(VHF)excitation on the electron density in such discharges are analyzed.The simulation results show that the electron density does not linearly vary with the excitation frequency within from 90150 MHz.he maximum value occurs at an appropriate excitation frequency i.e.the transition frequency.Increasof the excitation frequency would effectively increase the electron density before the transition frequency,but decreases the density afterwards.is.Moreover,the densities of involved particle species,including H2+,H,Ar*,Ar+,SiH3+,SiH3,SiH3,SiH2are closely interrelated.
文摘In order to discuss the mechanisms of permanent fixation of wood compression set , compressed wood of Chinese fir (Cunninghamia lanceolata) was irradiated by gamma rays from 60 Co. The irradiation doses were 0 (for match specim ens), 10 3, 5×10 3, 10 4, 5×10 4, 10 5, 5×10 5, 10 6, 5×10 6 Gy, res pectively. Then the weight loss, the equilibrium moisture content (EMC), the rec overy of wood compression set after adsorption (RSA) and the recovery after imme rsion in water (RSW), as well as the creep behaviour under a dry specimen condit ion and under an adsorption and subsequent desorption condition were measured an d discussed. This research proves that the doses of gamma irradiation have great effect on weight loss, EMC, RSA, RSW of irradiated compressed wood of Chinese f ir. The weight loss and the EMC increase, the RSA and the RSW fall drastically w hen the irradiation doses exceed 10 6 Gy. Both the instantaneous compliance and the creep compliance of the irradiated specimens under the two measurement cond itions show the general trend of increase with the increase of gamma irradiation doses. It can be deduced that decomposition or decrystallization reactions happ en in the wood cell wall at high gamma irradiation doses, especially at doses of around 5×10 6 Gy. In addition, this research proves that decomposition of mai n components of cell wall of compressed wood will lead to fixation of compressio n set of wood to a certain degree.
文摘[Objective] This research aimed to establish an inductively coupled plasma mass spectrometry (ICP-MS) method for determination of five kinds of heavy metals (Pb, Cd, Cu, As and Hg) in Dendrobium candidium Wall. ex Lindl. [Method] The samples were digested in HNO3-H202 acids system by closed vessel microwave di- gestion. At the same time, internal standard was added to avoid the matrix effect. [Result] The five kinds of heavy meals all showed good linear relationships, and the correlation coefficients ranged from 0.998 2 to 0.999 9. The detection limits of the five kinds of heavy metals were in the range of 0.008-0.750 μg/L, while the stan- dard recovery rates were in the range of 90.4%-96.9%. The relative standard devi- ations ranged from 1.6% to 8.2%. The heavy metals in the Ginseng and Astragalus national standard samples were determined by the established ICP-MS method, and the results were in conformity with the standard values. [Conclusion] The established method has simple and convenient operation and accurate and reliable results, and it meets the requirements by determination of heavy metals in Dendrobium candididium Wall. ex Lindl.
基金Supported by Key Research and Development Plan(Agricultural Support Field)of Hunan Province in 2015(2015NK3016)
文摘This standard operating procedure stipulated the natural condition of pro- ducing area, cultivation technique, disease and pest control, harvest, quality stan- dard, packaging, transportation and storage of H. cordata, in order to provide a ba- sis for the standard cultivation of H. cordata.
基金Supported by Hubei Provincial Department of Education Youth Found(Q2014402)Key Project of Natural Science Foundation of Hubei Province(2011CDA037)+2 种基金Special Fund for Agro-scientific Research in the Public Interest of Hubei Province(2012DCA23)Hubei Provincial Key Laboratory of Mining Environmental Pollution Control and Remediation Open Foundation(2012106)Project of Outstanding Yong and Middleaged Scientific and Technological Innovation Team of Colleges and Universities in Hubei Province(T201223)~~
文摘[Objective] The Cu-tolerance and Cu enrichment capacity of TLSB2-K were investigated. [Method] The previously isolated TLSB2-K strain was identified though morphological observation, gram staining and 16S rDNA sequence alignment. In ad- dition, the effects of temperature, pH and osmotic pressure on the growth of strain were also investigated by using shaking culture. The Cu-tolerance and Cu enrich- ment capacity of TLSB2-K strain under Cu stress were also studied. [Result] The results showed TLSB2-K belongs to Bacillus spp., and its optimum growth conditions were as follows: temperature, 27 ~C; pH, 7.0; osmotic pressure, 1.1% NaCI. When the Cu concentration ranged from 100 mg/L to 500 mg/L, the strain grew well; when the Cu concentration ranged from 100 mg/L to 400 mg/L, the Cu content in bacteria was increased with the increase of Cu concentration; when the Cu con- centration was 400 mg/L and the incubation time was 30 h, the Cu content in bac- teria reached the peak (2 250 mg/kg); the highest tolerant concentration was 700 mg/L. [Conclusion] TLSB2-K strain had relatively high Cu tolerance and Cu enrich- ment capacity. They had important theoretical research and engineering application values.
基金Supported by Shandong Provincial Natural Science Foundation in China(ZR2011CM034)~~
文摘In the research, changes of apple chemistry, and molecule, under stresses, are n terms of morphology, physiology, bio- illustrated and research and identifica- tion methods of apple resistance are explored involving drought-resistance, flood-re- sistance, salt-stress resistance, cold-hardiness and heat-resistance. In addition prospects of apple resistance research are proposed, as well.
基金Supported by Key Program of the National Natural Science Foundation of China(61233006)Key Science and Technology Program of Shanxi Province(20130311010-1)
文摘[Objective] This study aimed to investigate the growth and development and dry matter production and allocation of greenhouse tomato in North China. [Method] With tomato cultivar 'Jinguo No.l' as the experimental material, the ex- periments were conducted in a solar greenhouse located in Taigu, Shanxi (37o25' N, 112o25' E) from March to July, in 2014 and 2015. [Result] The plant height, leaf number, leaf area and dry matter production of greenhouse tomato increased lin- early with the increased days after transplantation, and their growth rates were 2.74 cm/d, 0.32 leaf/d, 70 cm2/d and 9.4 g/(m2.d), respectively. The fruit dry weight also showed a linear relationship with the plant dry weight. After fruit setting, the fruit dry weight was increased by about 0.69 g when the plant dry weight was increased by 1 g. The allocation proportions of dry matter in tomato roots, stems and leaves de- clined significantly from plant flowering to fruiting, while the proportion of fruit dry weight in plant dry weight increased significantly, exceeding 60%. There was a strong linear relationship between dry matter production of tomato and effective cu- mulative temperature (sum of temperature higher than 10 ^(3) in the solar green- house, and the dry matter production was increased by about 0.73 g/m2 when the effective cumulative temperature was increased by one unit. The dry matter produc- tion of tomato plant also showed a strong linear relationship with photosynthetic ac- tive radiation (PAR) in the greenhouse, and about 3.4 g of dry matter was synthe- sized per unit (M J) of PAR. [Conclusion] Extending the growing period and improv- ing the temperature and light conditions could increase the dry matter production of tomato.
基金Supported by the Central Public Interest Scientific Institution Basal Research Fund(1610172009003)the National Scientific Support Program of China(2010BAD01B05)~~
文摘[Objective] The aim of this study was to understand the difference of N fertilizer requirement between hybrid rapeseed and conventional rapeseed. [Method] Two hybrid cultivars, ZY5628 and ZY7819, and the conventional cultivar ZS10, were compared through two field experiments. In Experiment 1, seed yield and optimum N application rate were assessed in the field with five N application treatments. In Expedment 2, N was applied uniformly at 180 kg/hm2, and plant biomass and N accumulation were measured at several developmental stages, while N use efficien- cy was calculated for rape at maturity. [Results] The experiment 1 results showed that seed yields of ZY5628 and ZY7819 were both significantly higher than that of ZS10, and compared to ZS10, optimum yield (plateau yield) was higher by 18.7% and 20.2%, while the recommended N application rate was lower by 9.5% and 9.6% for ZY5628 and ZY7819, respectively. The experiment 2 results showed that during vegetative development, all three cultivars exhibited similar accumulations of plant biomass and N, but through flowering and maturity ZY5628 and ZY7819 pro- duced more biomass, acquired more N, and utilized acquired N more efficiently to- wards seed production than ZS10. [Conclusion] With equivalent inputs, the hybrid rapeseed cultivars ZY5628 and ZY7819 tested herein yield more seed with higher N use efficiency than the conventional rapeseed ZS10. This information will be valu- able for growers seeking to improve efficiency while reducing costs of rape production in China.