Estimation of leaf chlorophyll content(LCC) by proximal sensing is an important tool for photosynthesis evaluation in high-throughput phenotyping. The temporal variability of crop biochemical properties and canopy str...Estimation of leaf chlorophyll content(LCC) by proximal sensing is an important tool for photosynthesis evaluation in high-throughput phenotyping. The temporal variability of crop biochemical properties and canopy structure across different growth stages has great impacts on wheat LCC estimation, known as growth stage effects. It will result in the heterogeneity of crop canopy at different growth stages, which would mask subtle spectral response of biochemistry variations. This study aims to explore spectral responses on the growth stage effects and establish LCC models suited for different growth stages. A total number of 864 pairwise samples of wheat canopy spectra and LCC values with 216 observations of each stage were sampled at the tillering, jointing, booting and heading stages in 2021. Firstly, statistical analysis of LCC and spectral response presented different distribution traits and typical spectral variations peak at 470, 520 and 680 nm. Correlation analysis between LCC and reflectance showed typical red edge shifts. Secondly, the testing model of partial least square(PLS) established by the entire datasets to validate the predictive performance at each stage yielded poor LCC estimation accuracy. The spectral wavelengths of red edge(RE) and blue edge(BE) shifts and the poor estimation capability motivated us to further explore the growth stage effects by establishing LCC models at respective growth periods.Finally, competitive adaptive reweighted sampling PLS(CARS-PLS), decision tree(DT) and random forest(RF) were used to select sensitive bands and establish LCC models at specific stages. Bayes optimisation was used to tune the hyperparameters of DT and RF regression. The modelling results indicated that CARS-PLS and DT did not extract specific wavelengths that could decrease the influences of growth stage effects. From the RF out-of-bag(OOB) evaluation, the sensitive wavelengths displayed consistent spectral shifts from BE to GP and from RE to RV from tillering to heading stages. Compared with CARS-PLS and DT,results of RF modelling yielded an estimation accuracy with deviation to performance(RPD) of 2.11, 2.02,3.21 and 3.02, which can accommodate the growth stage effects. Thus, this study explores spectral response on growth stage effects and provides models for chlorophyll content estimation to satisfy the requirement of high-throughput phenotyping.展开更多
Complex superimposed basins exhibit multi-stage tectonic events and multi-stage reservoir formation; hydrocarbon reservoirs formed in the early stage have generally late-stage genesis characteristics after undergoing ...Complex superimposed basins exhibit multi-stage tectonic events and multi-stage reservoir formation; hydrocarbon reservoirs formed in the early stage have generally late-stage genesis characteristics after undergoing adjustment, reconstruction and destruction of later-stage multiple tectonic events. In this paper, this phenomenon is called the late-stage reservoir formation effect. The late-stage reservoir formation effect is a basic feature of oil and gas-forming reservoirs in complex superimposed basins, revealing not only multi-stage character, relevance and complexity of oil and gas- forming reservoirs in superimposed basins but also the importance of late-stage reservoir formation. Late-stage reservoir formation is not a basic feature of oil and gas forming reservoir in superimposed basins. Multi-stage reservoir formation only characterizes one aspect of oil and gas-forming reservoir in superimposed basins and does not represent fully the complexity of oil and gas-forming reservoir in superimposed basins. We suggest using ＂late-stage reservoir formation effect＂ to replace the ＂late-stage reservoir formation＂ concept to guide the exploration of complex reservoirs in superimposed basins. Under current geologic conditions, the late-stage reservoir formation effect is represented mainly by four basic forms： phase transformation, scale reconstruction, component variation and trap adjustment. The late-stage reservoir formation effect is produced by two kinds of geologic processes： first, the oil and gas retention function of various geologic thresholds （hydrocarbon expulsion threshold, hydrocarbon migration threshold, and hydrocarbon accumulating threshold） causes the actual time of oil and gas reservoir formation to be later than the time of generation of large amounts of hydrocarbon in a conventional sense, producing the late-stage reservoir formation effect; second, multiple types of tectonic events （continuously strong reconstruction, early-stage strong reconstruction, middle-stage strong reconstruction, late-stage strong reconstruction and long-term stable sedimentation） after oil and gas reservoir formation lead to adjustment, reconstruction and destruction of reservoirs formed earlier, and form new secondary hydrocarbon reservoirs due to the late-stage reservoir formation effect.展开更多
Natural secondary forest has a strong capacity to regrow naturally and recover biodiversity rapidly on abandoned lands.However,at the neighborhood scale,which can truly reflect the facilitative or competitive interact...Natural secondary forest has a strong capacity to regrow naturally and recover biodiversity rapidly on abandoned lands.However,at the neighborhood scale,which can truly reflect the facilitative or competitive interactions among individual plants,the local diversity spatial structure in secondary forest and the feedback effects of neighborhood diversity on natural regeneration remain unclear,and this may be the key to properly understand the mechanisms of natural secondary forest species diversity recovery.To this end,this study established a dynamic plot in a rehabilitated secondary forest after disturbance and conducted a comprehensive survey of 68,336 individual plants with repeated measurements at 5-year interval to assess the characteristics of neighborhood diversity structure across life history stages and link the neighborhood species richness(NSR)effect translated by species interactions at species diversity structure with individual trees recruitment/mortality in secondary forest regeneration.The results showed that,compared with tropical and temperate natural forests,a higher proportion of diversity accumulators and a lower proportion of repellers in subtropical secondary forests resulted in neighborhood diversity structures characterized by heterospecific or high-diversity patches,which are beneficial to the maintenance or restoration of biodiversity.As an important supplement to the research on the relationship between diversity and productivity,our findings show a positive diversity-survival relationship in subtropical secondary forests.Importantly,we observed that the neighborhood diversity structure exhibited a trend of accumulator-dominated to neutral-dominant changes with life stage from sapling to adult,which,in turn,determined the direction and strength of NSR effects on recruitment/mortality.Specifically,diverse local neighborhoods at a later successional stage characterized with‘neutral’species-species interactions can act as a‘welfare net’by offering favorable microhabitats for the most vulnerable recruitments or saplings,i.e.,the NSR effects that promoted individual recruitment/survival in our study.These results not only enrich our understanding of the biodiversity-productivity-survival relationship but also highlight the importance of retaining latesuccessional species of native trees in intensive forest production or in situ conservation policies.展开更多
Effects of river water from the Yangtze River （Nanjing section） on fish development, vitellogenin （VTG） induction, gonado-somatic index （GSI） and sex ratio were investigated by exposing goldfish （Carassius aura...Effects of river water from the Yangtze River （Nanjing section） on fish development, vitellogenin （VTG） induction, gonado-somatic index （GSI） and sex ratio were investigated by exposing goldfish （Carassius auratus） in the early life stage （from fertilization to 28 days post-hatch） to water samples （25%, 50% and 100%） collected from three representative sections. The results showed that there was no significant effect on hatching success for any of the exposure groups, but survival was significantly reduced when compared with the control （P 0.05）. Body lengths, weights of all treated fish did not differ significantly from those of the control. Condition factors （CF） of larval fish exposed to 50% and 100% river water from the Jiangxinzhou section and 100% river water from the Daqiao section were significantly lower than that of the control （P 0.05）. VTG inductions were significant in larval fish exposed to all the dilution series of river water. No significant difference in CF value was observed in any exposure group after 150 days of depuration. VTG was fully eliminated after 75 days of depuration. For both female and male, GSI did not significantly differ between exposure groups and the control after 150 days of convalescence. The highest female：male ratios were observed in response to the treatment with 50% or 100% river water from the Jiangxinzhou section and 100% river water from the Daqiao section （53：47, 56：44 and 54：46, respectively）, but no significant difference in sex ratio was observed in any treated group when compared to the control. The results showed that early life stage exposure of river water from the Yangtze River （Nanjing section） had adverse effects on goldfish development and reproductive health, and the effects on CF and VTG were reversible after depuration in clean water.展开更多
To screen new biological formulations, accurate and efficient application technology, field test was conducted with 72% Bacillus thuringiensis(Bt)·monosultap WP, 8% lambda-cyhalothrin·emamectin benzoate SA a...To screen new biological formulations, accurate and efficient application technology, field test was conducted with 72% Bacillus thuringiensis(Bt)·monosultap WP, 8% lambda-cyhalothrin·emamectin benzoate SA and 3.6% lambda-cyhalothrin·Bt SA through manual spraying and unmanned aerial vehicle spraying. Test results and comprehensive evaluation analysis demonstrated that 72% Bt·monosultap WP and 8%lambda-cyhalothrin·emamectin benzoate SA by manual spraying and unmanned aerial vehicle spraying had good prevention and control effect on strains and internodes damaged by Tryporyza intacta Snellen in middle and late stage, which were ideal new biological formulations with high effi-ciency and low risk for prevention and control of T. intacta in middle and late stage, and could be popularized in sugarcane area. 72% Bt·monosultap WP at the dose of 3 000 g/hectare and 8% lambda-cyhalothrin·emamectin benzoate SA at the dose of 750 mL/hectare could be sprayed in mid September at the peak occurrence period of the forth and fifth generations of T. intacta and Proceras venosatus. Agents were diluted with 900 kg water per hectare, and manually sprayed with electric knapsack sprayer; or agents were diluted with 15 kg of Haoyang aerial control special addi-tives and water per hectare, and sprayed with unmanned aerial vehicle. The control effect against borer-damaged strain rate was above 81.3% and that against borer-damaged internode rate was above 88.6%.展开更多
A delayed predator-prey model concerning impulsive spraying pesticides and releasing natural enemies is proposed and investigated,in which both the prey and the predator have a history that takes them through two stag...A delayed predator-prey model concerning impulsive spraying pesticides and releasing natural enemies is proposed and investigated,in which both the prey and the predator have a history that takes them through two stages:immature and mature.The global attractiveness of the pest-eradication periodic solution is discussed,and sufficient condition is obtained for the permanence of the system.Further,numerical simulations show that there is a characteristic sequence of bifurcations leading to a chaotic dynamics,which implies that the system with constant periodic impulsive perturbations admits rich and complex dynamics.展开更多
BACKGROUND： Central coordination disturbance is regarded as the early-stage symptom of brain injury-induced cerebral palsy. This disease manifests itself as motor disorder, abnormal attitudinal reflex and muscular te...BACKGROUND： Central coordination disturbance is regarded as the early-stage symptom of brain injury-induced cerebral palsy. This disease manifests itself as motor disorder, abnormal attitudinal reflex and muscular tension. Early intervention may improve its prognosis. OBJECTIVE： To observe the effects of intervention treatment from different stages on the prognosis of central coordination disturbance following brain injury in children patients. DESIGN： A contrast observation experiment SETTING： Department of Neurology and Rehabilitation, Urumqi Children＇s Hospital PARTICIPANTS ： Totally 151 children who were diagnosed as central coordination disturbance from January 2002 to December 2003 in the Department of Neurology and Rehabilitation of Urumqi Children＇s Hospital were recruited. All the children patients, including 101 male and 50 female, aged from 3 months to 1 year old, met the diagnosis criteria of central coordination disturbance from Vojta. They were divided into slight, moderate and severe abnormity according to Vojta attitudinal reflex. All 151 patients were divided into 2 groups according to their age at diagnosis： 3-6 months old group （n=74）, 62 severe, 10 moderate and 2 slight; 7-12 months old group （n=77）, 66 severe, 7 moderate and 4 slight. All the relatives of children patients were informed of the experiment. METHODS： ① Both groups received physical training （PT） as the main treatment; Hand training was given if necessary. All of the patients received additional hyperbaric oxygen therapy, bioelectric therapy, scalp acupuncture, drug treatment and family training. The importance of integration of hospital and family based rehabilitation was stressed. Those who did not catch up with the normal development or had abnormal reflexes continued to receive treatment. ② Around the age of 2 years old, all children did a final evaluation using Bayley Scales of Infant Development （BSID）. Mental development index （MDI） and physical development index （PDI） were taken as evaluative criteria. Children with scores 80 and above on MDI and PDI were considered to have normal motor and mental development; 79 and below were considered delayers. The Diagnostic Criteria of Cerebral Palsy and Infantecondary School Social Adaptation Scale were used in the final evaluation[scores ≤5 was extremely severe （extremely severe cerebral palsy）, 6 was severe（severe cerebral palsy）, 7 was moderate（moderate cerebral palsy）, 8 was slight（slight cerebral palsy）, 9 was borderline（slight cerebral palsy）, 10 was normal, 11 was above average, 12 was excellent and ≥13 was extremely excellent]. ③ Final evaluative results of 2 groups were compared. And u test was used for the comparison of Bayley development index and Chi-square test for the comparison of normalization rate. MAIN OUTCOME MEASURES： BSID MDI and PDI as well as the normalization rate of motor function and mental behavior of children patients at 2 years old. RESULTS： Totally 151 children patients entered the stage of result analysis. ①Two groups of children patients were given integrated rehabilitation therapy , and evaluated at 2 years old . The 3-6 months old group had higher MDI and PDI than the 7-12 months old group （91.81＋19.99 vs 71.93＋18.98;91.55＋23.61 vs 68.95＋23.51, u=6.265,5.894,P 〈 0.01 ）.②After being given integrated rehabilitation therapy, children patients of 3-6 months old group had significantly higher normalization rate of motor function and mental behavior than 7-12 months old group （73% ,27%,X2=29.723 9,P 〈 0.01 ）. ③Six slight and 17 moderate central coordination disturbance children of 2 groups all completely recovered; After intervention treatment, among 128 severe central coordination disturbance children, 52 recovered and 76 were still abnormal, in which, 43 slight cerebral palsy, 18 moderate cerebral palsy, 5 severe cerebral palsy and 10 extremely severe cerebral palsy. CONCLUSION： To perform integrated intervention treatment before 6 months old can better improve and promote mental and physical development levels of children patients with central coordination disturbance after brain injury than 6 months later.展开更多
In this paper, a predator -prey model with stage structure and double time delays in pollution environment is modeled. By using comparison theorem of impulsive differential equation, dynamics behaviors of the system i...In this paper, a predator -prey model with stage structure and double time delays in pollution environment is modeled. By using comparison theorem of impulsive differential equation, dynamics behaviors of the system is analysised. We prove that the pest-extinction solution of the system is the globally attractive for R 1 <1.展开更多
The definition of multi-stage decision dynamic system with after-effects is given.As a special case of it, the definition of dynamic economic system with after-effects is proposed.
In this paper, an aeronautical thin-walled part with a complex geometry which has several sharp bends and curvatures in different directions was investigated. This kind of part is difficult to be manufactured only in ...In this paper, an aeronautical thin-walled part with a complex geometry which has several sharp bends and curvatures in different directions was investigated. This kind of part is difficult to be manufactured only in one stage. Therefore, an innovative multi-stage active hydroforming process assisted by the rigid forming method was designed. In addition, an optimized blank geometry is obtained. In fact, the main focused point of this paper is to propose a new small radius rounded corner forming technique and analyze the mechanism. Two kinds of forming modes of changing a big rounded corner into a small one, which are related to different tangential positions of the die in the process of calibration, are analyzed theoretically. Meanwhile, the stress and strain states of the deformation region are compared. The relationships between the minimum relative radii of rounded corners I and II in the first stage and the hydraulic pressure are calculated by the bending theory. Finally, the influences of the tensile-bulging effect and the interface condition of the double-layer sheet on the forming quality of the specimen are investigated. The achieved results can make a foundation for utilizing the proposed method in forming of thin-walled parts with very small radii.展开更多
基金supported by the National Key Research and Development Program (2019YFE0125500)University-Locality Integrative Development Project of Yantai (2020XDRHXMPT35)+1 种基金the National Natural Science Foundation of China (31971785 and41801245)the Graduate Training Project of China Agricultural University (JG2019004, JG202026, YW2020007, QYJC202101, and JG202102)。
文摘Estimation of leaf chlorophyll content(LCC) by proximal sensing is an important tool for photosynthesis evaluation in high-throughput phenotyping. The temporal variability of crop biochemical properties and canopy structure across different growth stages has great impacts on wheat LCC estimation, known as growth stage effects. It will result in the heterogeneity of crop canopy at different growth stages, which would mask subtle spectral response of biochemistry variations. This study aims to explore spectral responses on the growth stage effects and establish LCC models suited for different growth stages. A total number of 864 pairwise samples of wheat canopy spectra and LCC values with 216 observations of each stage were sampled at the tillering, jointing, booting and heading stages in 2021. Firstly, statistical analysis of LCC and spectral response presented different distribution traits and typical spectral variations peak at 470, 520 and 680 nm. Correlation analysis between LCC and reflectance showed typical red edge shifts. Secondly, the testing model of partial least square(PLS) established by the entire datasets to validate the predictive performance at each stage yielded poor LCC estimation accuracy. The spectral wavelengths of red edge(RE) and blue edge(BE) shifts and the poor estimation capability motivated us to further explore the growth stage effects by establishing LCC models at respective growth periods.Finally, competitive adaptive reweighted sampling PLS(CARS-PLS), decision tree(DT) and random forest(RF) were used to select sensitive bands and establish LCC models at specific stages. Bayes optimisation was used to tune the hyperparameters of DT and RF regression. The modelling results indicated that CARS-PLS and DT did not extract specific wavelengths that could decrease the influences of growth stage effects. From the RF out-of-bag(OOB) evaluation, the sensitive wavelengths displayed consistent spectral shifts from BE to GP and from RE to RV from tillering to heading stages. Compared with CARS-PLS and DT,results of RF modelling yielded an estimation accuracy with deviation to performance(RPD) of 2.11, 2.02,3.21 and 3.02, which can accommodate the growth stage effects. Thus, this study explores spectral response on growth stage effects and provides models for chlorophyll content estimation to satisfy the requirement of high-throughput phenotyping.
基金State Key Basic Research "973" Program (2006CB202308) for funding this research
文摘Complex superimposed basins exhibit multi-stage tectonic events and multi-stage reservoir formation; hydrocarbon reservoirs formed in the early stage have generally late-stage genesis characteristics after undergoing adjustment, reconstruction and destruction of later-stage multiple tectonic events. In this paper, this phenomenon is called the late-stage reservoir formation effect. The late-stage reservoir formation effect is a basic feature of oil and gas-forming reservoirs in complex superimposed basins, revealing not only multi-stage character, relevance and complexity of oil and gas- forming reservoirs in superimposed basins but also the importance of late-stage reservoir formation. Late-stage reservoir formation is not a basic feature of oil and gas forming reservoir in superimposed basins. Multi-stage reservoir formation only characterizes one aspect of oil and gas-forming reservoir in superimposed basins and does not represent fully the complexity of oil and gas-forming reservoir in superimposed basins. We suggest using ＂late-stage reservoir formation effect＂ to replace the ＂late-stage reservoir formation＂ concept to guide the exploration of complex reservoirs in superimposed basins. Under current geologic conditions, the late-stage reservoir formation effect is represented mainly by four basic forms： phase transformation, scale reconstruction, component variation and trap adjustment. The late-stage reservoir formation effect is produced by two kinds of geologic processes： first, the oil and gas retention function of various geologic thresholds （hydrocarbon expulsion threshold, hydrocarbon migration threshold, and hydrocarbon accumulating threshold） causes the actual time of oil and gas reservoir formation to be later than the time of generation of large amounts of hydrocarbon in a conventional sense, producing the late-stage reservoir formation effect; second, multiple types of tectonic events （continuously strong reconstruction, early-stage strong reconstruction, middle-stage strong reconstruction, late-stage strong reconstruction and long-term stable sedimentation） after oil and gas reservoir formation lead to adjustment, reconstruction and destruction of reservoirs formed earlier, and form new secondary hydrocarbon reservoirs due to the late-stage reservoir formation effect.
基金supported by the Innovative Team Project of Nanjing Institute of Environmental Sciences,MEECentral Public Welfare Scientific Institution Basal Research Fund,Ministry of Finance and Ministry of Ecology and Environment of China(Nos.GYZX210302,GYZX200203):Biodiversity Survey,Observation and Assessment Program of Ministry of Ecology and Environment of China+2 种基金The National Environmental Protection Public Welfare Industry Targeted Research Fund:Research and demonstration of key technologies for dynamic supervision of nature reserves(No.201509042)The Special Foundation for National Science and Technology Basic Resources Investigation of China(No.2019FY202300)The Jiangsu Postdoctoral Research Funding Program(No.2021K038A)。
文摘Natural secondary forest has a strong capacity to regrow naturally and recover biodiversity rapidly on abandoned lands.However,at the neighborhood scale,which can truly reflect the facilitative or competitive interactions among individual plants,the local diversity spatial structure in secondary forest and the feedback effects of neighborhood diversity on natural regeneration remain unclear,and this may be the key to properly understand the mechanisms of natural secondary forest species diversity recovery.To this end,this study established a dynamic plot in a rehabilitated secondary forest after disturbance and conducted a comprehensive survey of 68,336 individual plants with repeated measurements at 5-year interval to assess the characteristics of neighborhood diversity structure across life history stages and link the neighborhood species richness(NSR)effect translated by species interactions at species diversity structure with individual trees recruitment/mortality in secondary forest regeneration.The results showed that,compared with tropical and temperate natural forests,a higher proportion of diversity accumulators and a lower proportion of repellers in subtropical secondary forests resulted in neighborhood diversity structures characterized by heterospecific or high-diversity patches,which are beneficial to the maintenance or restoration of biodiversity.As an important supplement to the research on the relationship between diversity and productivity,our findings show a positive diversity-survival relationship in subtropical secondary forests.Importantly,we observed that the neighborhood diversity structure exhibited a trend of accumulator-dominated to neutral-dominant changes with life stage from sapling to adult,which,in turn,determined the direction and strength of NSR effects on recruitment/mortality.Specifically,diverse local neighborhoods at a later successional stage characterized with‘neutral’species-species interactions can act as a‘welfare net’by offering favorable microhabitats for the most vulnerable recruitments or saplings,i.e.,the NSR effects that promoted individual recruitment/survival in our study.These results not only enrich our understanding of the biodiversity-productivity-survival relationship but also highlight the importance of retaining latesuccessional species of native trees in intensive forest production or in situ conservation policies.
基金supported by the National Natural Science Foundation of China (No. 51079049)the National Basic Research Program (973) of China (No. 2010CB429006)
文摘Effects of river water from the Yangtze River （Nanjing section） on fish development, vitellogenin （VTG） induction, gonado-somatic index （GSI） and sex ratio were investigated by exposing goldfish （Carassius auratus） in the early life stage （from fertilization to 28 days post-hatch） to water samples （25%, 50% and 100%） collected from three representative sections. The results showed that there was no significant effect on hatching success for any of the exposure groups, but survival was significantly reduced when compared with the control （P 0.05）. Body lengths, weights of all treated fish did not differ significantly from those of the control. Condition factors （CF） of larval fish exposed to 50% and 100% river water from the Jiangxinzhou section and 100% river water from the Daqiao section were significantly lower than that of the control （P 0.05）. VTG inductions were significant in larval fish exposed to all the dilution series of river water. No significant difference in CF value was observed in any exposure group after 150 days of depuration. VTG was fully eliminated after 75 days of depuration. For both female and male, GSI did not significantly differ between exposure groups and the control after 150 days of convalescence. The highest female：male ratios were observed in response to the treatment with 50% or 100% river water from the Jiangxinzhou section and 100% river water from the Daqiao section （53：47, 56：44 and 54：46, respectively）, but no significant difference in sex ratio was observed in any treated group when compared to the control. The results showed that early life stage exposure of river water from the Yangtze River （Nanjing section） had adverse effects on goldfish development and reproductive health, and the effects on CF and VTG were reversible after depuration in clean water.
基金Supported by Special Fund of China Agricultural (Sugar) Industry Research System(CARS-170303)Training Project of Yunling Industry and Technology Leading Talents "Control of Sugarcane Harm-ful Organisms"(2018LJRC56)Special Fund of Agricultural Industry Research System in Yunnan Province
文摘To screen new biological formulations, accurate and efficient application technology, field test was conducted with 72% Bacillus thuringiensis(Bt)·monosultap WP, 8% lambda-cyhalothrin·emamectin benzoate SA and 3.6% lambda-cyhalothrin·Bt SA through manual spraying and unmanned aerial vehicle spraying. Test results and comprehensive evaluation analysis demonstrated that 72% Bt·monosultap WP and 8%lambda-cyhalothrin·emamectin benzoate SA by manual spraying and unmanned aerial vehicle spraying had good prevention and control effect on strains and internodes damaged by Tryporyza intacta Snellen in middle and late stage, which were ideal new biological formulations with high effi-ciency and low risk for prevention and control of T. intacta in middle and late stage, and could be popularized in sugarcane area. 72% Bt·monosultap WP at the dose of 3 000 g/hectare and 8% lambda-cyhalothrin·emamectin benzoate SA at the dose of 750 mL/hectare could be sprayed in mid September at the peak occurrence period of the forth and fifth generations of T. intacta and Proceras venosatus. Agents were diluted with 900 kg water per hectare, and manually sprayed with electric knapsack sprayer; or agents were diluted with 15 kg of Haoyang aerial control special addi-tives and water per hectare, and sprayed with unmanned aerial vehicle. The control effect against borer-damaged strain rate was above 81.3% and that against borer-damaged internode rate was above 88.6%.
基金Foundation item： Supported by the NNSF of China（11071254） Supported by the Science Foundation of Mechanical Engineering College（YJJXMll004）
文摘A delayed predator-prey model concerning impulsive spraying pesticides and releasing natural enemies is proposed and investigated,in which both the prey and the predator have a history that takes them through two stages:immature and mature.The global attractiveness of the pest-eradication periodic solution is discussed,and sufficient condition is obtained for the permanence of the system.Further,numerical simulations show that there is a characteristic sequence of bifurcations leading to a chaotic dynamics,which implies that the system with constant periodic impulsive perturbations admits rich and complex dynamics.
文摘BACKGROUND： Central coordination disturbance is regarded as the early-stage symptom of brain injury-induced cerebral palsy. This disease manifests itself as motor disorder, abnormal attitudinal reflex and muscular tension. Early intervention may improve its prognosis. OBJECTIVE： To observe the effects of intervention treatment from different stages on the prognosis of central coordination disturbance following brain injury in children patients. DESIGN： A contrast observation experiment SETTING： Department of Neurology and Rehabilitation, Urumqi Children＇s Hospital PARTICIPANTS ： Totally 151 children who were diagnosed as central coordination disturbance from January 2002 to December 2003 in the Department of Neurology and Rehabilitation of Urumqi Children＇s Hospital were recruited. All the children patients, including 101 male and 50 female, aged from 3 months to 1 year old, met the diagnosis criteria of central coordination disturbance from Vojta. They were divided into slight, moderate and severe abnormity according to Vojta attitudinal reflex. All 151 patients were divided into 2 groups according to their age at diagnosis： 3-6 months old group （n=74）, 62 severe, 10 moderate and 2 slight; 7-12 months old group （n=77）, 66 severe, 7 moderate and 4 slight. All the relatives of children patients were informed of the experiment. METHODS： ① Both groups received physical training （PT） as the main treatment; Hand training was given if necessary. All of the patients received additional hyperbaric oxygen therapy, bioelectric therapy, scalp acupuncture, drug treatment and family training. The importance of integration of hospital and family based rehabilitation was stressed. Those who did not catch up with the normal development or had abnormal reflexes continued to receive treatment. ② Around the age of 2 years old, all children did a final evaluation using Bayley Scales of Infant Development （BSID）. Mental development index （MDI） and physical development index （PDI） were taken as evaluative criteria. Children with scores 80 and above on MDI and PDI were considered to have normal motor and mental development; 79 and below were considered delayers. The Diagnostic Criteria of Cerebral Palsy and Infantecondary School Social Adaptation Scale were used in the final evaluation[scores ≤5 was extremely severe （extremely severe cerebral palsy）, 6 was severe（severe cerebral palsy）, 7 was moderate（moderate cerebral palsy）, 8 was slight（slight cerebral palsy）, 9 was borderline（slight cerebral palsy）, 10 was normal, 11 was above average, 12 was excellent and ≥13 was extremely excellent]. ③ Final evaluative results of 2 groups were compared. And u test was used for the comparison of Bayley development index and Chi-square test for the comparison of normalization rate. MAIN OUTCOME MEASURES： BSID MDI and PDI as well as the normalization rate of motor function and mental behavior of children patients at 2 years old. RESULTS： Totally 151 children patients entered the stage of result analysis. ①Two groups of children patients were given integrated rehabilitation therapy , and evaluated at 2 years old . The 3-6 months old group had higher MDI and PDI than the 7-12 months old group （91.81＋19.99 vs 71.93＋18.98;91.55＋23.61 vs 68.95＋23.51, u=6.265,5.894,P 〈 0.01 ）.②After being given integrated rehabilitation therapy, children patients of 3-6 months old group had significantly higher normalization rate of motor function and mental behavior than 7-12 months old group （73% ,27%,X2=29.723 9,P 〈 0.01 ）. ③Six slight and 17 moderate central coordination disturbance children of 2 groups all completely recovered; After intervention treatment, among 128 severe central coordination disturbance children, 52 recovered and 76 were still abnormal, in which, 43 slight cerebral palsy, 18 moderate cerebral palsy, 5 severe cerebral palsy and 10 extremely severe cerebral palsy. CONCLUSION： To perform integrated intervention treatment before 6 months old can better improve and promote mental and physical development levels of children patients with central coordination disturbance after brain injury than 6 months later.
文摘In this paper, a predator -prey model with stage structure and double time delays in pollution environment is modeled. By using comparison theorem of impulsive differential equation, dynamics behaviors of the system is analysised. We prove that the pest-extinction solution of the system is the globally attractive for R 1 <1.
文摘The definition of multi-stage decision dynamic system with after-effects is given.As a special case of it, the definition of dynamic economic system with after-effects is proposed.
基金supported by the National Science and Technology Major Project of China (No. 2014ZX04002041)
文摘In this paper, an aeronautical thin-walled part with a complex geometry which has several sharp bends and curvatures in different directions was investigated. This kind of part is difficult to be manufactured only in one stage. Therefore, an innovative multi-stage active hydroforming process assisted by the rigid forming method was designed. In addition, an optimized blank geometry is obtained. In fact, the main focused point of this paper is to propose a new small radius rounded corner forming technique and analyze the mechanism. Two kinds of forming modes of changing a big rounded corner into a small one, which are related to different tangential positions of the die in the process of calibration, are analyzed theoretically. Meanwhile, the stress and strain states of the deformation region are compared. The relationships between the minimum relative radii of rounded corners I and II in the first stage and the hydraulic pressure are calculated by the bending theory. Finally, the influences of the tensile-bulging effect and the interface condition of the double-layer sheet on the forming quality of the specimen are investigated. The achieved results can make a foundation for utilizing the proposed method in forming of thin-walled parts with very small radii.
