[Objective] The paper was to study the effect of tobacco blown spot on the yield and output value of tobacco leaf.[Method]The upper,middle and lower leaves in tobacco plant were selected during the harvest period of t...[Objective] The paper was to study the effect of tobacco blown spot on the yield and output value of tobacco leaf.[Method]The upper,middle and lower leaves in tobacco plant were selected during the harvest period of tobacco to carry out loss rate estimation of yield and output value of tobacco leaf caused by different disease levels of brown spot.Regression correlation analysis was also conducted.[Result]The disease levels of brown spot had extremely significant strong negative correlation with single leaf weight of tobacco leaf,and it had extremely significant strong positive correlation with the loss rate of single leaf weight.The increase speed of loss rate of single leaf weight of middle and upper leaves was obviously faster than that of lower leaves.The loss rates of single leaf weight of upper,middle and lower leaves were 3.18%-28.95%,3.43%-28.88% and 10.07%-26.90%,respectively.The higher the disease level of blown spot was,the lower the yield and output value of tobacco leaf was,and the corresponding loss rate was also higher.Correlation analysis showed that the disease level of blown spot had extremely significant strong negative correlation with the yield and output value of tobacco leaf,and it had extremely significant strong positive correlation with the loss rate of yield and output value.The negative impact of blown spot on the output value of tobacco leaf was far greater than that on the yield.The highest loss rate of the yield of tobacco leaf was 28.56%,while the highest loss rate of output value reached 89.67%.[Conclusion] The study provided theoretical basis for accurately holding the critical period for the control of blown spot,thus reducing the damage on tobacco leaf and improving the output value of tobacco leaf.展开更多
To better understand the physiological characteristics of the silky starling(Sturnus sericeus), its body temperature(Tb), basal metabolic rate(BMR), evaporative water loss(EWL) and thermal conductance(C) eli...To better understand the physiological characteristics of the silky starling(Sturnus sericeus), its body temperature(Tb), basal metabolic rate(BMR), evaporative water loss(EWL) and thermal conductance(C) elicited by different ambient temperatures(Ta)(5-30 ℃) were determined in the present study. Our results showed that they have a high Tb(41.6±0.1 ℃), a wide thermal neutral zone(TNZ)(20-27.5 ℃) and a relatively low BMR within the TNZ(3.37±0.17 mL O2/g·h). The EWL was nearly stable below the TNZ(0.91±0.07 mg H2O/g·h) but increased remarkably within and above the TNZ. The C was constant below the TNZ, with a minimum value of 0.14±0.01 mL O2/g·h·℃. These findings indicate that the BMR, Tb and EWL of the silky starling were all affected by Ta, especially when Ta was below 20℃ and the EWL plays an important role in thermal regulation.展开更多
In order to cope with drought and water shortages,the working people in the arid areas of Northwest China have developed a drought-resistant planting method,namely,gravel-sand mulching,after long-term agricultural pra...In order to cope with drought and water shortages,the working people in the arid areas of Northwest China have developed a drought-resistant planting method,namely,gravel-sand mulching,after long-term agricultural practices.To understand the effects of gravel-sand mulching on soil water evaporation,we selected Baifeng peach(Amygdalus persica L.)orchards in Northwest China as the experimental field in 2021.Based on continuously collected soil water stable isotopes data,we evaluated the soil evaporation loss rate in a gravel-sand mulching environment using the line-conditioned excess(lc-excess)coupled Rayleigh fractionation model and Craig-Gordon model.The results show that the average soil water content in the plots with gravel-sand mulching is 1.86%higher than that without gravel-sand mulching.The monthly variation of the soil water content is smaller in the plots with gravel-sand mulching than that without gravel-sand mulching.Moreover,the average lc-excess value in the plots without gravel-sand mulching is smaller.In addition,the soil evaporation loss rate in the plots with gravel-sand mulching is lower than that in the plots without gravel-sand mulching.The lc-excess value was negative for both the plots with and without gravel-sand mulching,and it has good correlation with relative humidity,average temperature,input water content,and soil water content.The effect of gravel-sand mulching on soil evaporation is most prominent in August.Compared with the evaporation data of similar environments in the literature,the lc-excess coupled Rayleigh fractionation model is better.Stable isotopes evidence shows that gravel-sand mulching can effectively reduce soil water evaporation,which provides a theoretical basis for agricultural water management and optimization of water-saving methods in arid areas.展开更多
<span style="font-family:Verdana;">The main reason for the early failure of radio-cephalic arteriovenous fistula (RCAVF) is non-maturity, which means that the blood flow rate in the fistula cannot incr...<span style="font-family:Verdana;">The main reason for the early failure of radio-cephalic arteriovenous fistula (RCAVF) is non-maturity, which means that the blood flow rate in the fistula cannot increase to the expected value for dialysis. From a mechanical perspective, the vascular resistance at the artificially designed anastomosis causes an energy loss that affects blood flow rate growth and leads to early failure. This research studied how to maximize the RCAVF maturity and primary patency by controlling the energy loss rate. We theoretically analyzed and derived a model that evaluates the energy loss rate <em>E</em><sub><em>avf</em></sub> in RCAVF as a function of its blood vessel geometric parameters (GPs) for given flow rates. There was an aggregate of five controllable GPs in RCAVF: radial artery diameter (<em>D</em><sub><em>ra</em></sub>), cephalic vein diameter (<em>D</em><sub><em>cv</em></sub>), blood vessel distance between artery and vein (<em>h</em>), anastomotic diameter (<em>D</em><sub><em>a</em></sub>), and anastomotic angle (<em>θ</em>). Through this analysis, it was found that <em>E</em><sub><em>avf</em></sub> was inversely proportional to <em>D</em><sub><em>ra</em></sub>, <em>D</em><sub><em>cv</em></sub>, <em>D</em><sub><em>a</em></sub>, and <em>θ</em>, whereas proportional to <em>h</em>. Therefore, we recommended surgeons choose the vessels with large diameters, close distance, and increase the diameter and angle of the anastomosis to decrease the early failure of RCAVF. Simultaneously, we could explain the results of many clinical empiricisms with our formula. We found that increasing <em>D</em><sub><em>cv</em></sub> and <em>θ</em> was more significant in reducing <em>E</em><sub><em>avf</em></sub> than increasing <em>D</em><sub><em>ra</em></sub> and <em>D</em><sub><em>a</em></sub>. Based on our model, we could define two critical energy loss rates (<em>CEL</em><sub><em>a</em></sub>, <em>CEL</em><sub><em>b</em></sub>) to help surgeons evaluate the blood vessels and choose the ideal range of <em>θ</em>, and help them design the preoperative RCAVF plan for each patient to increase the maturity and the primary patency of RCAVF.</span>展开更多
The analysis of cell loss rates in an ATM Mux with loss priorities is an important problem in the-study of traffic control in ATM networks. In this paper, the loss rates of the cells with different priorities in an AT...The analysis of cell loss rates in an ATM Mux with loss priorities is an important problem in the-study of traffic control in ATM networks. In this paper, the loss rates of the cells with different priorities in an ATM Mux are analyzed by approximating the actual input process with two-state MMDP and fluid flow technique, and the analytical expressions of the relation between the loss rates and the buffer size are obtained. Simulation shows that the approach is sulliciently accurate for applications.展开更多
A study was conducted with the objective of improvement of water use efficiency (WUE) and yield of winter wheat for Lowland Dryland Farming systems through a breeding approach. Various genotypes were screened in 1988 ...A study was conducted with the objective of improvement of water use efficiency (WUE) and yield of winter wheat for Lowland Dryland Farming systems through a breeding approach. Various genotypes were screened in 1988 for rate of water loss of excised leaves (RWL) , followed by inter-crossing of diverse parents in 1993. Analysis of the relationship between RWL and yield components and plant traits demonstrated significant differences in RWL among genotypes. Under most circumstances, RWL was correlated negatively with yield and grain weight, and positively with plant height. The results demonstrated a basis for simultaneous selection for high yield and low RWL. It was found that genotypic rank varied with the duration of water loss. Correlation between RWL and yield was reduced by extended water loss duration. Analysis of the genetic variation and segregation of RWL of progenies and the effect of simultaneous screening for RWL and agronomic traits showed that good lines with improved yield and water use performance could be obtained.展开更多
<b><span>Background:</span></b><span> The objective of this meta-analysis was to assess whether mini-</span><span>implants </span><span>have</span><span&g...<b><span>Background:</span></b><span> The objective of this meta-analysis was to assess whether mini-</span><span>implants </span><span>have</span><span> added benefit in terms of implants success rate and average bone loss over conventional-sized implants after one year of follow-up.</span><span> </span><b><span>Methods: </span></b><span>An electronic search of randomized clinical trials was conducted in MEDLINE (via PubMed), Cochrane Central Register of Clinical Trials (CENTRAL) and Web of Science for studies including complete or partial edentulous patients requiring two or four mini-implants or conventional/</span><span> </span><span>standard-sized implants in the maxilla or mandible for implant-supported removable prostheses who completed 12 months of follow-up. </span><b><span>Results:</span></b><span> The search provided 194 unique articles which were screened for title and abstract. Screening generated 12 articles which went through full-text analysis using eligibility criteria, and 4 articles were included for meta-analysis. Meta-analysis of these studies indicated a non-significant difference in the success rate between the two interventions (OR = 1.69 [0.74, 3.85;p = 0.21]). Bone loss estimates resulted in a significant bone reduction (Mean Difference = </span><span>-</span><span>0.74 [</span><span>-</span><span>0.95, </span><span>-</span><span>0.53;p < 0.05]) in favor of two mini-implants when compared with two conventional-sized implants, but when compared four mini</span><span>- </span><span> </span><span>with two conventional-sized implants</span><span>,</span><span> the estimates were non-significant </span><span>(Mean Difference = </span><span>-</span><span>0.24 [</span><span>-</span><span>0.69, 0.20;p = 0.29]). </span><b><span>Conclusion: </span></b><span>The current evidence does not provide solid evidence of the benefits of one intervention over the other. More studies with follow-up times of 10 and more years are needed as current studies have described the short-term outcomes.</span>展开更多
The size and allocation method of transmission network loss have major impact on particular users involved with the electricity market trading process, therefore, the accuracy of scheduled network loss rates will be v...The size and allocation method of transmission network loss have major impact on particular users involved with the electricity market trading process, therefore, the accuracy of scheduled network loss rates will be vital to the economic concerns from the stakeholders. In view of the shortcoming of existing loss rate scheme in 1,000 kV demonstration project, three scheduled loss rates applied to the UHV AC (ultra high voltage alternating current) transaction settlement are revised. By taking relationship between loss rate and power into consideration, the new segmented correction scheme greatly reduces the deviation between scheduled loss rates and actual loss rates, and is more accurate, flexible and expansible than the old one.展开更多
The objective of this study is to find a suitable method to overcome the pressure loss problem in the gas pipe during the gas exchange detection of medical masks.Based on the European Standards EN 14683,the parameters...The objective of this study is to find a suitable method to overcome the pressure loss problem in the gas pipe during the gas exchange detection of medical masks.Based on the European Standards EN 14683,the parameters of a medical mask differential pressure tester were selected,subsequently two schemes of gas pipe layouts were designed,including four kinds of pipe diameter which are 4,5,6.5,and 8mm respectively.Lastly,the models of each scheme were established and imported into Fluent,and the relevant parameters were set for simulation.After data analysis,the results showed that among the four different pipe diameters,the pressure loss of 8mm diameter of the pipe was lower in both the schemes,additionally the pressure loss of the second scheme(the gas pipe was short and smooth)was lower under the same pipe diameter.At the flow rate of v=8L/min,the pressure loss from the inlet to the measurement point is less than 200Pa,and the estimated measurement error is less than 1.5%.In conclusion,shortening the length of the pipe,and increasing the diameter of the pipe can reduce the gas pressure loss,subsequently improve the measurement accuracy of the medical mask differential pressure tester.展开更多
The aim of this study is to evaluate the uncertainty of 2πα and 2πβ surface emission rates using the windowless multiwire proportional counter method.This study used the Monte Carlo method (MCM) to validate the co...The aim of this study is to evaluate the uncertainty of 2πα and 2πβ surface emission rates using the windowless multiwire proportional counter method.This study used the Monte Carlo method (MCM) to validate the conventional Guide to the Expression of Uncertainty in Measurement (GUM) method.A dead time measurement model for the two-source method was established based on the characteristics of a single-channel measurement system,and the voltage threshold correction factor measurement function was indirectly obtained by fitting the threshold correction curve.The uncertainty in the surface emission rate was calculated using the GUM method and the law of propagation of uncertainty.The MCM provided clear definitions for each input quantity and its uncertainty distribution,and the simulation training was realized with a complete and complex mathematical model.The results of the surface emission rate uncertainty evaluation for four radioactive plane sources using both methods showed the uncertainty’s consistency E_(n)<0.070 for the comparison of each source,and the uncertainty results of the GUM were all lower than those of the MCM.However,the MCM has a more objective evaluation process and can serve as a validation tool for GUM results.展开更多
In this paper, we construct the EB estim ation for the parameter of the two-dimensional one side truncat ed distribution fam ilies using Linex loss. The convergence rate of EB estimation is given and it is shown tha...In this paper, we construct the EB estim ation for the parameter of the two-dimensional one side truncat ed distribution fam ilies using Linex loss. The convergence rate of EB estimation is given and it is shown that the proposed empirical Bayes estimaiton can be arbitrarily close to 1 under certain conditions.展开更多
In this paper we propose an absolute error loss EB estimator for parameter of one-side truncation distribution families. Under some conditions we have proved that the convergence rates of its Bayes risk is o, where 0&...In this paper we propose an absolute error loss EB estimator for parameter of one-side truncation distribution families. Under some conditions we have proved that the convergence rates of its Bayes risk is o, where 0<λ,r≤1,Mn≤lnln n (for large n),Mn→∞ as n→∞.展开更多
Although nitrogen (N) loss through runoff and leaching from croplands is suspected to contribute to the deterioration of surrounding water systems, there is no conclusive evidence for paddy soils to prove this hypot...Although nitrogen (N) loss through runoff and leaching from croplands is suspected to contribute to the deterioration of surrounding water systems, there is no conclusive evidence for paddy soils to prove this hypothesis. In this study, field plot experiments were conducted to investigate N losses through runoff and leaching for two consecutive years with 3 N fertilization rates in rice (Oryza sativa L.)-wheat (Triticum aestivum L.) rotations in the Taihu Lake region, China. A water collection system was designed to collect runoff and leachates for both the rice and wheat seasons. Results showed that dissolved N (DN), rather than particulate N (PN), was the main form of N loss by runoff. The NO3^--N concentration in runoff was between 0.1 and 43.7 mg L^-1, whereas the NH4^+-N concentration ranged from below detection limit to 8.5 mg L^-1. Total N (TN) loads by runoff were 1.0-17.9 and 5.2-38.6 kg ha^-1 during rice and wheat seasons, respectively, and the main loss occurred at the early growing stage of the crops. Nitrogen concentrations in leachates during the rice seasons were below 1.0 mg L^-1 and independent of the N application rate, whereas those during the wheat season increased to 8.2 mg L^-1 and were affected by the fertilizer rate. Annual losses of TN through runoff and leaching were 13.7-48.1 kg ha^-1 from the rice-wheat cropping system, accounting for 5.6%-8.3% of the total applied N. It was concluded that reduction in the N fertilization rate, especially when the crop was small in biomass, could lower the N pollution potential for water systems.展开更多
Excessive nitrogen (N) fertilizer application to winter wheat is a common problem on the North China Plain. To determine the optimum fertilizer N rate for winter wheat production while minimizing N losses, field exper...Excessive nitrogen (N) fertilizer application to winter wheat is a common problem on the North China Plain. To determine the optimum fertilizer N rate for winter wheat production while minimizing N losses, field experiments were conducted for two growing seasons at eight sites, in Huimin County, Shandong Province, from 2001 to 2003. The optimum N rate for maximum grain yield was inversely related to the initial soil mineral N content (Nmin) in the top 90 cm of the soil profile before sowing. There was no yield response to the applied N at the three sites with high initial soil mineral N levels (average 212 kg N ha-1). The average optimum N rate was 96 kg N ha-1 for the five sites with low initial soil Nmin (average 155 kg N ha-1) before sowing. Residual nitrate N in the top 90 cm of the soil profile after harvest increased with increasing fertilizer N application rate. The apparent N losses during the wheat-growing season also increased with increasing N application rate. The average apparent N losses with the optimum N rates were less than 15 kg N ha-1, whereas the farmers' conventional N application rate resulted in losses of more than 100 kg N ha-1. Therefore, optimizing N use for winter wheat considerably reduced N losses to the environment without compromising crop yields.展开更多
On the basis of a general model of fuel cells, the entropy production rates of a fuel cell system under different conditions are derived by using theories of electrochemistry and thermodynamics. In order to analyze th...On the basis of a general model of fuel cells, the entropy production rates of a fuel cell system under different conditions are derived by using theories of electrochemistry and thermodynamics. In order to analyze the influence of the irreversible losses existing in an actual fuel cell, the equivalent circuit of the fuel cell is introduced, so that the irreversible factor of the fuel cell may be determined directly as a function of the internal, leak and load resistances. Moreover, the maximum power output and efficiency of the fuel cell are calculated, the optimal operation of the fuel cell is discussed, and the matching condition of the load resistance is determined.展开更多
Due to the meteorological factors, Henan Province had a large-scale outbreak of corn stalk rot in 2014, and the incidence status of 25 varieties was investigated. According to the relevant resistance identification st...Due to the meteorological factors, Henan Province had a large-scale outbreak of corn stalk rot in 2014, and the incidence status of 25 varieties was investigated. According to the relevant resistance identification standards, Xundan.509 was classified as resistance variety; Yudan606, Jinsai38 and Xundan3136 were classified as moderate resistance ones, while the other 21 varieties were highly susceptible varieties. Using the yield loss rate of 5% as the critical value of disease tolerance standard, XundanS09, Yudan606, Jinsai38, Xundan3136, Huaiyu5288, QiaoyuS, XY046, Zhengyu10, Lile66, WeikeT02 and Xundan29 were classified into tolerance varieties of corn stalk rot. The concept between disease resistance and disease tolerance was distinguished. The diseased plant rate was used as the classification basis of disease resistance and the yield loss rate was used as the evaluation standard of disease tolerance. The relationship between both was showed by a Venn diagram.展开更多
This paper considers a robust kernel regularized classification algorithm with a non-convex loss function which is proposed to alleviate the performance deterioration caused by the outliers.A comparison relationship b...This paper considers a robust kernel regularized classification algorithm with a non-convex loss function which is proposed to alleviate the performance deterioration caused by the outliers.A comparison relationship between the excess misclassification error and the excess generalization error is provided;from this,along with the convex analysis theory,a kind of learning rate is derived.The results show that the performance of the classifier is effected by the outliers,and the extent of impact can be controlled by choosing the homotopy parameters properly.展开更多
Flow against pipeline leakage and the pipe network sudden burst pipe to pipeline leakage flow for the application objects,network congestion avoidance strategy is designed in pipeline leak monitoring.Based on the prop...Flow against pipeline leakage and the pipe network sudden burst pipe to pipeline leakage flow for the application objects,network congestion avoidance strategy is designed in pipeline leak monitoring.Based on the property of Markov chain for network data,a new estimator with particle filter is proposed for congestion control in this paper.The proposed scheme can predict the traffic patterns by the decision-making model.To compare with previous scheme based on fuzzy neural network,the proposed scheme can adaptively adjust the network rate in real-time and reduce the cell loss rate,so that it can avoid the traffic congestion.Simulation results show that network congestion avoidance strategy with particle filter can improve the bandwidth utilization,Transmission Control Protocol (TCP) friendliness and reduce the packet drop rate in Pipeline Flux Leak Monitoring networks.展开更多
To improve the utilization efficiency of water the laying length of porous tubes was analyzed. Considering long porous tubes the irrigation uniformity of porous tubes was studied by analyzing the deviation rate of the...To improve the utilization efficiency of water the laying length of porous tubes was analyzed. Considering long porous tubes the irrigation uniformity of porous tubes was studied by analyzing the deviation rate of the working head of porous tubes and through an impact analysis of the deviation ratio of flow rate based on laying length slope pressure head and perforation spacing. Results showed that the deviation ratio of the flow rate could be reduced by decreasing the length of tubes and increasing the slope. The deviation ratio of flow rate was less influenced by pressure head and perforation spacing. A best laid slope resulted in a longer laying length of the porous tubes and they were not constant.展开更多
Thermal manikin plays important roles in simulating thethermal state of human bodies to facilitate the evaluationof thermal comfort properties of various clothing assem-blies.Based on the heat balance principle and an...Thermal manikin plays important roles in simulating thethermal state of human bodies to facilitate the evaluationof thermal comfort properties of various clothing assem-blies.Based on the heat balance principle and analysis ofrelated factors,the heat production rate of manikin isrecommended as an efficient evaluation index.Whereas,its inside heat production which occurs as a result of theexistence of temperature difference between its insidepart and outside surface,should not be ignored.Through a series of theoretical analysis and calculations,a compensative equation is deduced in this paper.展开更多
基金Supported by State Tobacco Monopoly Administration Project "National Survey of Pests in Tobacco" (110200902065)Yunnan Tobacco Monopoly Bureau Technology Project " Investigation of Tobacco Pests in Yunnan Province" (2010YN19)~~
文摘[Objective] The paper was to study the effect of tobacco blown spot on the yield and output value of tobacco leaf.[Method]The upper,middle and lower leaves in tobacco plant were selected during the harvest period of tobacco to carry out loss rate estimation of yield and output value of tobacco leaf caused by different disease levels of brown spot.Regression correlation analysis was also conducted.[Result]The disease levels of brown spot had extremely significant strong negative correlation with single leaf weight of tobacco leaf,and it had extremely significant strong positive correlation with the loss rate of single leaf weight.The increase speed of loss rate of single leaf weight of middle and upper leaves was obviously faster than that of lower leaves.The loss rates of single leaf weight of upper,middle and lower leaves were 3.18%-28.95%,3.43%-28.88% and 10.07%-26.90%,respectively.The higher the disease level of blown spot was,the lower the yield and output value of tobacco leaf was,and the corresponding loss rate was also higher.Correlation analysis showed that the disease level of blown spot had extremely significant strong negative correlation with the yield and output value of tobacco leaf,and it had extremely significant strong positive correlation with the loss rate of yield and output value.The negative impact of blown spot on the output value of tobacco leaf was far greater than that on the yield.The highest loss rate of the yield of tobacco leaf was 28.56%,while the highest loss rate of output value reached 89.67%.[Conclusion] The study provided theoretical basis for accurately holding the critical period for the control of blown spot,thus reducing the damage on tobacco leaf and improving the output value of tobacco leaf.
基金This study was financially supported the National Natural Science Foundation of China (31070366), the Natural Science Foundation (LY13C030005) in Zhejiang Province and the Zhejiang Province 'Xinmiao' Project.
文摘To better understand the physiological characteristics of the silky starling(Sturnus sericeus), its body temperature(Tb), basal metabolic rate(BMR), evaporative water loss(EWL) and thermal conductance(C) elicited by different ambient temperatures(Ta)(5-30 ℃) were determined in the present study. Our results showed that they have a high Tb(41.6±0.1 ℃), a wide thermal neutral zone(TNZ)(20-27.5 ℃) and a relatively low BMR within the TNZ(3.37±0.17 mL O2/g·h). The EWL was nearly stable below the TNZ(0.91±0.07 mg H2O/g·h) but increased remarkably within and above the TNZ. The C was constant below the TNZ, with a minimum value of 0.14±0.01 mL O2/g·h·℃. These findings indicate that the BMR, Tb and EWL of the silky starling were all affected by Ta, especially when Ta was below 20℃ and the EWL plays an important role in thermal regulation.
基金supportedby the National Natural Science Foundation of China(41771035,42071047)。
文摘In order to cope with drought and water shortages,the working people in the arid areas of Northwest China have developed a drought-resistant planting method,namely,gravel-sand mulching,after long-term agricultural practices.To understand the effects of gravel-sand mulching on soil water evaporation,we selected Baifeng peach(Amygdalus persica L.)orchards in Northwest China as the experimental field in 2021.Based on continuously collected soil water stable isotopes data,we evaluated the soil evaporation loss rate in a gravel-sand mulching environment using the line-conditioned excess(lc-excess)coupled Rayleigh fractionation model and Craig-Gordon model.The results show that the average soil water content in the plots with gravel-sand mulching is 1.86%higher than that without gravel-sand mulching.The monthly variation of the soil water content is smaller in the plots with gravel-sand mulching than that without gravel-sand mulching.Moreover,the average lc-excess value in the plots without gravel-sand mulching is smaller.In addition,the soil evaporation loss rate in the plots with gravel-sand mulching is lower than that in the plots without gravel-sand mulching.The lc-excess value was negative for both the plots with and without gravel-sand mulching,and it has good correlation with relative humidity,average temperature,input water content,and soil water content.The effect of gravel-sand mulching on soil evaporation is most prominent in August.Compared with the evaporation data of similar environments in the literature,the lc-excess coupled Rayleigh fractionation model is better.Stable isotopes evidence shows that gravel-sand mulching can effectively reduce soil water evaporation,which provides a theoretical basis for agricultural water management and optimization of water-saving methods in arid areas.
文摘<span style="font-family:Verdana;">The main reason for the early failure of radio-cephalic arteriovenous fistula (RCAVF) is non-maturity, which means that the blood flow rate in the fistula cannot increase to the expected value for dialysis. From a mechanical perspective, the vascular resistance at the artificially designed anastomosis causes an energy loss that affects blood flow rate growth and leads to early failure. This research studied how to maximize the RCAVF maturity and primary patency by controlling the energy loss rate. We theoretically analyzed and derived a model that evaluates the energy loss rate <em>E</em><sub><em>avf</em></sub> in RCAVF as a function of its blood vessel geometric parameters (GPs) for given flow rates. There was an aggregate of five controllable GPs in RCAVF: radial artery diameter (<em>D</em><sub><em>ra</em></sub>), cephalic vein diameter (<em>D</em><sub><em>cv</em></sub>), blood vessel distance between artery and vein (<em>h</em>), anastomotic diameter (<em>D</em><sub><em>a</em></sub>), and anastomotic angle (<em>θ</em>). Through this analysis, it was found that <em>E</em><sub><em>avf</em></sub> was inversely proportional to <em>D</em><sub><em>ra</em></sub>, <em>D</em><sub><em>cv</em></sub>, <em>D</em><sub><em>a</em></sub>, and <em>θ</em>, whereas proportional to <em>h</em>. Therefore, we recommended surgeons choose the vessels with large diameters, close distance, and increase the diameter and angle of the anastomosis to decrease the early failure of RCAVF. Simultaneously, we could explain the results of many clinical empiricisms with our formula. We found that increasing <em>D</em><sub><em>cv</em></sub> and <em>θ</em> was more significant in reducing <em>E</em><sub><em>avf</em></sub> than increasing <em>D</em><sub><em>ra</em></sub> and <em>D</em><sub><em>a</em></sub>. Based on our model, we could define two critical energy loss rates (<em>CEL</em><sub><em>a</em></sub>, <em>CEL</em><sub><em>b</em></sub>) to help surgeons evaluate the blood vessels and choose the ideal range of <em>θ</em>, and help them design the preoperative RCAVF plan for each patient to increase the maturity and the primary patency of RCAVF.</span>
文摘The analysis of cell loss rates in an ATM Mux with loss priorities is an important problem in the-study of traffic control in ATM networks. In this paper, the loss rates of the cells with different priorities in an ATM Mux are analyzed by approximating the actual input process with two-state MMDP and fluid flow technique, and the analytical expressions of the relation between the loss rates and the buffer size are obtained. Simulation shows that the approach is sulliciently accurate for applications.
文摘A study was conducted with the objective of improvement of water use efficiency (WUE) and yield of winter wheat for Lowland Dryland Farming systems through a breeding approach. Various genotypes were screened in 1988 for rate of water loss of excised leaves (RWL) , followed by inter-crossing of diverse parents in 1993. Analysis of the relationship between RWL and yield components and plant traits demonstrated significant differences in RWL among genotypes. Under most circumstances, RWL was correlated negatively with yield and grain weight, and positively with plant height. The results demonstrated a basis for simultaneous selection for high yield and low RWL. It was found that genotypic rank varied with the duration of water loss. Correlation between RWL and yield was reduced by extended water loss duration. Analysis of the genetic variation and segregation of RWL of progenies and the effect of simultaneous screening for RWL and agronomic traits showed that good lines with improved yield and water use performance could be obtained.
文摘<b><span>Background:</span></b><span> The objective of this meta-analysis was to assess whether mini-</span><span>implants </span><span>have</span><span> added benefit in terms of implants success rate and average bone loss over conventional-sized implants after one year of follow-up.</span><span> </span><b><span>Methods: </span></b><span>An electronic search of randomized clinical trials was conducted in MEDLINE (via PubMed), Cochrane Central Register of Clinical Trials (CENTRAL) and Web of Science for studies including complete or partial edentulous patients requiring two or four mini-implants or conventional/</span><span> </span><span>standard-sized implants in the maxilla or mandible for implant-supported removable prostheses who completed 12 months of follow-up. </span><b><span>Results:</span></b><span> The search provided 194 unique articles which were screened for title and abstract. Screening generated 12 articles which went through full-text analysis using eligibility criteria, and 4 articles were included for meta-analysis. Meta-analysis of these studies indicated a non-significant difference in the success rate between the two interventions (OR = 1.69 [0.74, 3.85;p = 0.21]). Bone loss estimates resulted in a significant bone reduction (Mean Difference = </span><span>-</span><span>0.74 [</span><span>-</span><span>0.95, </span><span>-</span><span>0.53;p < 0.05]) in favor of two mini-implants when compared with two conventional-sized implants, but when compared four mini</span><span>- </span><span> </span><span>with two conventional-sized implants</span><span>,</span><span> the estimates were non-significant </span><span>(Mean Difference = </span><span>-</span><span>0.24 [</span><span>-</span><span>0.69, 0.20;p = 0.29]). </span><b><span>Conclusion: </span></b><span>The current evidence does not provide solid evidence of the benefits of one intervention over the other. More studies with follow-up times of 10 and more years are needed as current studies have described the short-term outcomes.</span>
文摘The size and allocation method of transmission network loss have major impact on particular users involved with the electricity market trading process, therefore, the accuracy of scheduled network loss rates will be vital to the economic concerns from the stakeholders. In view of the shortcoming of existing loss rate scheme in 1,000 kV demonstration project, three scheduled loss rates applied to the UHV AC (ultra high voltage alternating current) transaction settlement are revised. By taking relationship between loss rate and power into consideration, the new segmented correction scheme greatly reduces the deviation between scheduled loss rates and actual loss rates, and is more accurate, flexible and expansible than the old one.
文摘The objective of this study is to find a suitable method to overcome the pressure loss problem in the gas pipe during the gas exchange detection of medical masks.Based on the European Standards EN 14683,the parameters of a medical mask differential pressure tester were selected,subsequently two schemes of gas pipe layouts were designed,including four kinds of pipe diameter which are 4,5,6.5,and 8mm respectively.Lastly,the models of each scheme were established and imported into Fluent,and the relevant parameters were set for simulation.After data analysis,the results showed that among the four different pipe diameters,the pressure loss of 8mm diameter of the pipe was lower in both the schemes,additionally the pressure loss of the second scheme(the gas pipe was short and smooth)was lower under the same pipe diameter.At the flow rate of v=8L/min,the pressure loss from the inlet to the measurement point is less than 200Pa,and the estimated measurement error is less than 1.5%.In conclusion,shortening the length of the pipe,and increasing the diameter of the pipe can reduce the gas pressure loss,subsequently improve the measurement accuracy of the medical mask differential pressure tester.
文摘The aim of this study is to evaluate the uncertainty of 2πα and 2πβ surface emission rates using the windowless multiwire proportional counter method.This study used the Monte Carlo method (MCM) to validate the conventional Guide to the Expression of Uncertainty in Measurement (GUM) method.A dead time measurement model for the two-source method was established based on the characteristics of a single-channel measurement system,and the voltage threshold correction factor measurement function was indirectly obtained by fitting the threshold correction curve.The uncertainty in the surface emission rate was calculated using the GUM method and the law of propagation of uncertainty.The MCM provided clear definitions for each input quantity and its uncertainty distribution,and the simulation training was realized with a complete and complex mathematical model.The results of the surface emission rate uncertainty evaluation for four radioactive plane sources using both methods showed the uncertainty’s consistency E_(n)<0.070 for the comparison of each source,and the uncertainty results of the GUM were all lower than those of the MCM.However,the MCM has a more objective evaluation process and can serve as a validation tool for GUM results.
文摘In this paper, we construct the EB estim ation for the parameter of the two-dimensional one side truncat ed distribution fam ilies using Linex loss. The convergence rate of EB estimation is given and it is shown that the proposed empirical Bayes estimaiton can be arbitrarily close to 1 under certain conditions.
文摘In this paper we propose an absolute error loss EB estimator for parameter of one-side truncation distribution families. Under some conditions we have proved that the convergence rates of its Bayes risk is o, where 0<λ,r≤1,Mn≤lnln n (for large n),Mn→∞ as n→∞.
基金the National Natural Science Foundation of China (Nos.40571077 and 30390080)and the Knowledge Innovation Project of the Chinese Academy of Sciences (No.KZCX2-413).
文摘Although nitrogen (N) loss through runoff and leaching from croplands is suspected to contribute to the deterioration of surrounding water systems, there is no conclusive evidence for paddy soils to prove this hypothesis. In this study, field plot experiments were conducted to investigate N losses through runoff and leaching for two consecutive years with 3 N fertilization rates in rice (Oryza sativa L.)-wheat (Triticum aestivum L.) rotations in the Taihu Lake region, China. A water collection system was designed to collect runoff and leachates for both the rice and wheat seasons. Results showed that dissolved N (DN), rather than particulate N (PN), was the main form of N loss by runoff. The NO3^--N concentration in runoff was between 0.1 and 43.7 mg L^-1, whereas the NH4^+-N concentration ranged from below detection limit to 8.5 mg L^-1. Total N (TN) loads by runoff were 1.0-17.9 and 5.2-38.6 kg ha^-1 during rice and wheat seasons, respectively, and the main loss occurred at the early growing stage of the crops. Nitrogen concentrations in leachates during the rice seasons were below 1.0 mg L^-1 and independent of the N application rate, whereas those during the wheat season increased to 8.2 mg L^-1 and were affected by the fertilizer rate. Annual losses of TN through runoff and leaching were 13.7-48.1 kg ha^-1 from the rice-wheat cropping system, accounting for 5.6%-8.3% of the total applied N. It was concluded that reduction in the N fertilization rate, especially when the crop was small in biomass, could lower the N pollution potential for water systems.
基金Project supported by the National Natural Science Foundation of China (Nos. 30390084 and 30270772)the Natural Science Foundation of Beijing (No. 6010001)
文摘Excessive nitrogen (N) fertilizer application to winter wheat is a common problem on the North China Plain. To determine the optimum fertilizer N rate for winter wheat production while minimizing N losses, field experiments were conducted for two growing seasons at eight sites, in Huimin County, Shandong Province, from 2001 to 2003. The optimum N rate for maximum grain yield was inversely related to the initial soil mineral N content (Nmin) in the top 90 cm of the soil profile before sowing. There was no yield response to the applied N at the three sites with high initial soil mineral N levels (average 212 kg N ha-1). The average optimum N rate was 96 kg N ha-1 for the five sites with low initial soil Nmin (average 155 kg N ha-1) before sowing. Residual nitrate N in the top 90 cm of the soil profile after harvest increased with increasing fertilizer N application rate. The apparent N losses during the wheat-growing season also increased with increasing N application rate. The average apparent N losses with the optimum N rates were less than 15 kg N ha-1, whereas the farmers' conventional N application rate resulted in losses of more than 100 kg N ha-1. Therefore, optimizing N use for winter wheat considerably reduced N losses to the environment without compromising crop yields.
文摘On the basis of a general model of fuel cells, the entropy production rates of a fuel cell system under different conditions are derived by using theories of electrochemistry and thermodynamics. In order to analyze the influence of the irreversible losses existing in an actual fuel cell, the equivalent circuit of the fuel cell is introduced, so that the irreversible factor of the fuel cell may be determined directly as a function of the internal, leak and load resistances. Moreover, the maximum power output and efficiency of the fuel cell are calculated, the optimal operation of the fuel cell is discussed, and the matching condition of the load resistance is determined.
基金Supported by Major Science and Technology Project of Henan Province"Gene Mining of Important Agronomic Traits in Major Crops and Breeding of New Corn Varieties"(161100110500-0104)
文摘Due to the meteorological factors, Henan Province had a large-scale outbreak of corn stalk rot in 2014, and the incidence status of 25 varieties was investigated. According to the relevant resistance identification standards, Xundan.509 was classified as resistance variety; Yudan606, Jinsai38 and Xundan3136 were classified as moderate resistance ones, while the other 21 varieties were highly susceptible varieties. Using the yield loss rate of 5% as the critical value of disease tolerance standard, XundanS09, Yudan606, Jinsai38, Xundan3136, Huaiyu5288, QiaoyuS, XY046, Zhengyu10, Lile66, WeikeT02 and Xundan29 were classified into tolerance varieties of corn stalk rot. The concept between disease resistance and disease tolerance was distinguished. The diseased plant rate was used as the classification basis of disease resistance and the yield loss rate was used as the evaluation standard of disease tolerance. The relationship between both was showed by a Venn diagram.
基金supported by the NSF(61877039)the NSFC/RGC Joint Research Scheme(12061160462 and N City U 102/20)of China+2 种基金the NSF(LY19F020013)of Zhejiang Provincethe Special Project for Scientific and Technological Cooperation(20212BDH80021)of Jiangxi Provincethe Science and Technology Project in Jiangxi Province Department of Education(GJJ211334)。
文摘This paper considers a robust kernel regularized classification algorithm with a non-convex loss function which is proposed to alleviate the performance deterioration caused by the outliers.A comparison relationship between the excess misclassification error and the excess generalization error is provided;from this,along with the convex analysis theory,a kind of learning rate is derived.The results show that the performance of the classifier is effected by the outliers,and the extent of impact can be controlled by choosing the homotopy parameters properly.
基金Xinjiang Production and Construction Corps Reforms Project Courses,China(No.200905)Tarim University Principal Youth Fund, China(No.TDZKQN05002)Tarim University Quality of Higher Education Courses and Research Funding,China(No.TDGJ0914)
文摘Flow against pipeline leakage and the pipe network sudden burst pipe to pipeline leakage flow for the application objects,network congestion avoidance strategy is designed in pipeline leak monitoring.Based on the property of Markov chain for network data,a new estimator with particle filter is proposed for congestion control in this paper.The proposed scheme can predict the traffic patterns by the decision-making model.To compare with previous scheme based on fuzzy neural network,the proposed scheme can adaptively adjust the network rate in real-time and reduce the cell loss rate,so that it can avoid the traffic congestion.Simulation results show that network congestion avoidance strategy with particle filter can improve the bandwidth utilization,Transmission Control Protocol (TCP) friendliness and reduce the packet drop rate in Pipeline Flux Leak Monitoring networks.
基金Sponsored by the National Natural Science Foundation of China(Grant Nos.11362019 and 11562018)
文摘To improve the utilization efficiency of water the laying length of porous tubes was analyzed. Considering long porous tubes the irrigation uniformity of porous tubes was studied by analyzing the deviation rate of the working head of porous tubes and through an impact analysis of the deviation ratio of flow rate based on laying length slope pressure head and perforation spacing. Results showed that the deviation ratio of the flow rate could be reduced by decreasing the length of tubes and increasing the slope. The deviation ratio of flow rate was less influenced by pressure head and perforation spacing. A best laid slope resulted in a longer laying length of the porous tubes and they were not constant.
文摘Thermal manikin plays important roles in simulating thethermal state of human bodies to facilitate the evaluationof thermal comfort properties of various clothing assem-blies.Based on the heat balance principle and analysis ofrelated factors,the heat production rate of manikin isrecommended as an efficient evaluation index.Whereas,its inside heat production which occurs as a result of theexistence of temperature difference between its insidepart and outside surface,should not be ignored.Through a series of theoretical analysis and calculations,a compensative equation is deduced in this paper.