The booming live-streaming commerce has significantly changed the traditional e-commerce model,thus attracting much attention from both industry and academia.In recent years,an increasing number of scholars have appli...The booming live-streaming commerce has significantly changed the traditional e-commerce model,thus attracting much attention from both industry and academia.In recent years,an increasing number of scholars have applied analytical models to explore live-streaming strategies for firms in different scenarios.However,the previous literature mainly considers monopolists,while in the real world,competition is not rare.To fill this gap between the literature and practical observations,this paper applies a game theoretical model to study live-streaming adoption and pricing strategy for firms under competitive environments.The results show that,for competitive firms,the equilibrium strategy depends on the relation between the commission rate and the intensity of the market expansion effect.Additionally,compared to the case in which no firm adopts live-streaming,competitive firms do not always benefit from the adoption of live-streaming selling.The paper also shows that competition plays a negative role in inducing a firm to adopt live-streaming.展开更多
This study considers an-particle jump-diffusion system with mean field interaction,where the coefficients are locally Lipschitz continuous.We address the convergence as n→∞of the empirical measure of the jump-diffus...This study considers an-particle jump-diffusion system with mean field interaction,where the coefficients are locally Lipschitz continuous.We address the convergence as n→∞of the empirical measure of the jump-diffusions to the solution of a deterministic McKean-Vlasov equation.The strong well-posedness of the associated McKean-Vlasov equation and a corresponding propagation of chaos result are proven.In particular,we also provide precise estimates of the convergence speed with respect to a Wasserstein-like metric.展开更多
In the era of network live broadcasting for everyone,the development of live broadcasting platforms is also more intelligent and diversified.However,in the face of a large group of elderly users,the interface interact...In the era of network live broadcasting for everyone,the development of live broadcasting platforms is also more intelligent and diversified.However,in the face of a large group of elderly users,the interface interaction design mode used is still mainly based on the interaction mode for young groups,and is not designed for elderly users.Therefore,a design method for optimizing the interaction interface of live broadcasting platform for elderly users was proposed in this study.Firstly,the case study method and Delphi expert survey method were used to determine the design needs of elderly users and the design mode was analysed.Secondly,the orthogonal design principle was used to design a test sample of the interactive interface of live broadcasting platform applicable for the elderly users,and then a user evaluation system was established to calculate the weights of the design elements using hierarchical analysis,and then the predictive relationship between the design mode of the interactive interface of live broadcasting platform and the elderly users was established by Quantitative Theory I.Finally,Genetic Algorithm was applied to generate the optimized design scheme.The results showed that the design method based on the Genetic Algorithm and the combination of Quantitative Theory can scientifically and effectively optimize the design of the interactive interface of the live broadcasting platform for the elderly users,and improve the experience of the elderly users.展开更多
The hot compression tests of 7Mo super austenitic stainless(SASS)were conducted to obtain flow curves at the temperature of 1000-1200℃and strain rate of 0.001 s^(-1)to 1 s^(-1).To predict the non-linear hot deformati...The hot compression tests of 7Mo super austenitic stainless(SASS)were conducted to obtain flow curves at the temperature of 1000-1200℃and strain rate of 0.001 s^(-1)to 1 s^(-1).To predict the non-linear hot deformation behaviors of the steel,back propagation-artificial neural network(BP-ANN)with 16×8×8 hidden layer neurons was proposed.The predictability of the ANN model is evaluated according to the distribution of mean absolute error(MAE)and relative error.The relative error of 85%data for the BP-ANN model is among±5%while only 42.5%data predicted by the Arrhenius constitutive equation is in this range.Especially,at high strain rate and low temperature,the MAE of the ANN model is 2.49%,which has decreases for 18.78%,compared with conventional Arrhenius constitutive equation.展开更多
As mobility and migration become the norm,citizens in modern cities live among people who remain strangers to each other.This creates new opportunities and challenges for urban social life.Public space is a critical f...As mobility and migration become the norm,citizens in modern cities live among people who remain strangers to each other.This creates new opportunities and challenges for urban social life.Public space is a critical forum in which strangers encounter each other and have the opportunity to develop social protocols for coexisting in diversity.New media technologies have huge impact on the form and quality of public space.Digital art can create experimental public spaces in which mediated connections and embodied presence are combined in new ways.Through the practice and research of digital art,we can imagine a communicative city in which urban digital media is less about spectacle,and more about promoting new forms of public speech and social encounter between people.展开更多
[Objective] This paper aimed to clarify the rice planting methods and its supporting technology to be developed in rice producing areas in China. [Method] Evolvement of rice planting methods in rice producing areas in...[Objective] This paper aimed to clarify the rice planting methods and its supporting technology to be developed in rice producing areas in China. [Method] Evolvement of rice planting methods in rice producing areas in China and in representative rice-growth countries abroad, its characteristics, adaptability and key issues were analyzed. [Result] The analysis of development of rice planting method in China and abroad indicated that rice planting method was adapted to rice-based cropping system and ecological environment, and its transition accompanied with social and economic development. With agricultural labor transfer from agriculture to other industries since 1990’s, rice seedling throwing was gradually applied and in recent decades, while direct seeding and machine transplanting were practiced. Now, hand transplanting is still the main rice planting method, adopted in 50% of national rice planting area; seedling throwing, direct seeding and machine transplanting are conducted in 25% , 12% and 13% of the national rice planting area. [Conclusion] Machine transplanting should be a leading rice planting method. Though area covered with machine direct seeding is still small up to now, it can be practiced in some rice growing area due to labor saving and low cost. Leading planting methods and its supporting key technologies are proposed in various rice producing areas in the future.展开更多
3D traveltime calculation is widely used in seismic exploration technologies such as seismic migration and tomography. The fast marching method (FMM) is useful for calculating 3D traveltime and has proven to be effi...3D traveltime calculation is widely used in seismic exploration technologies such as seismic migration and tomography. The fast marching method (FMM) is useful for calculating 3D traveltime and has proven to be efficient and stable. However, it has low calculation accuracy near the source, which thus gives it low overall accuracy. This paper proposes a joint traveltime calculation method to solve this problem. The method firstly employs the wavefront construction method (WFC), which has a higher calculation accuracy than FMM in calculating traveltime in the small area near the source, and secondly adopts FMM to calculate traveltime for the remaining grid nodes. Due to the increase in calculation precision of grid nodes near the source, this new algorithm is shown to have good calculation precision while maintaining the high calculation efficiency of FMM, which is employed in most of the computational area. Results are verified using various numerical models.展开更多
[Objective] This study aimed to investigate the effect of direct-seeding with non-flooding and wheat residue returning patterns on greenhouse gas emission from rice paddy. [Method] Two rice cultivars currently used in...[Objective] This study aimed to investigate the effect of direct-seeding with non-flooding and wheat residue returning patterns on greenhouse gas emission from rice paddy. [Method] Two rice cultivars currently used in the production, Yangdao 6 (an indica) and Yangjing 4038 (a japonica), were field grown using a direct-seeding method, and four treatments, wheat straw incorporation into soil and traditional flooding (SlF), non-flooding and wheat straw mulching (NSM), non-flooding and wheat straw incorporation into soil (NSl) and traditional flooding (no straw returned, Control, TF), were imposed after sowing to maturity. Effects of direct-seeding with non-flooding and wheat residue returning patterns on CH4, N20 and CO2 emissions were investigated by using the method of static chamber-gas chromatographic tech- niques. [Result] Grain yield showed no significant difference between non-flooding and flooding treatments, but was significantly higher under the SlF than under any other treatments. The emission flux of CH4 and CO2 under TF and SlF exhibited a single peak curve, while changed little under the NSl and NSM The emission flux of N2Oshowed multiple perk curves for all the treatments. Compared with TF, SlF significantly increased mean emission flux of CH4 or N2O, decreased emission of N20, while NSl and NSM significantly decreased the mean emission flux of OH4, and increased emission flux of N2O and CO2. SIF also increased Green Warm Potential (GWP) of CH4, N2O and CO2 and the GWP per unit grain yield by 47.3%- 53.7% and 32.2%-39.4%, respectively. Both NSl and NSM decreased GWP by 24.2%-29.6% and 30.1%-35.5%, and the GWP per unit grain yield was decreased by 21.7-27.2% and 25.6%-31.1%, respectively. [Conelusion] both NSl and NSM could significantly reduce greenhouse effect of CH4, N2O and CO2 meanwhile maintain a high grain yield.展开更多
In order to study the effect of rice straw returning and seeding patterns on seedling emergence and grain yield, field experiment was conducted to investi- gate the effects of straw mechanized returning and different ...In order to study the effect of rice straw returning and seeding patterns on seedling emergence and grain yield, field experiment was conducted to investi- gate the effects of straw mechanized returning and different seeding patterns on e- mergence rate, emergence uniformity and yield traits of wheat after rice. The results were as follows: in rice straw removal treatments, the emergence rate of mechani- cal seeding in drill was lower than that of mechanical uniform planting and manual broadcast sowing, which were 51.84%, 90.89% and 88.87%, respectively; the emer- gence uniformity of manual broadcast sowing was inferior to mechanical seeding in drill and mechanical uniform planting, which were 0.49, 0.26 and 0.23, respectively. As for the treatments with rice straw returning to the field, the emergence rate and emergence uniformity all decreased in the three seeding patterns, of which mechan- ical seeding in drill dropped markedly with emergence rate decreased by 36.54%. The emergence rate and emergence uniformity affected grain yield by affecting pan- icle, grains per spike and 1 000-grain weight. The grain yield for the treatment with rice straw removal was 6 091.34 kg/hm2, while that with rice straw returning to field was 6 476.20 kg/hm2, and both were higher than the yields of the other two seed- ing patterns. Therefore, mechanical uniform planting was?recommended for its higher emergence rate, better emergence uniformity, which was conductive to increase grain yield in wheat after rice production with rice straw returning to field.展开更多
This study was conducted for the purposes of reducing consumption of wild resources of Paris polyphylla Smith, satisfying the market demand, saving the production cost, improving utilization rate of forest land, incre...This study was conducted for the purposes of reducing consumption of wild resources of Paris polyphylla Smith, satisfying the market demand, saving the production cost, improving utilization rate of forest land, increasing income of foresters and protecting ecological environment. Three types of fores{ land, i.e., the evergreen forest land (China fir forest), deciduous forest land (walnut forest) and shrub land (honey suckle forest.) were selected, and seeds and cut rhizomes of Paris polyphylla Smith produced in Bamian Mountain, Hunan, were used in the study on understory seedling raising and cultivation techniques. The results showed that: when using different propagation materials, seed propagation could be adopted to reduce the consumption of wild resources and provide a large number of seedlings, and was beneficial to large-scale planting; and when conducing seedling and plantlet raising followed by transplanting and direct seeding and planting using different propagation materials in large-scale understory cultivation, direct seeding/ planting was appropriate for saving save production cost with the advantage of early production. Among the 3 different types of forest land, the best choice was broad- leaved forest land, which could achieve better economic benefit because of con- forming with the ecological habit and growth and development law of Paris poly- phylla Smith.展开更多
[Objective]The aim was to study the sensitive response characteristics of the main agronomic traits of somaclonal and the variation of sensitive response of the lines of somaclonal to sowing date. [Method]The RITSD ch...[Objective]The aim was to study the sensitive response characteristics of the main agronomic traits of somaclonal and the variation of sensitive response of the lines of somaclonal to sowing date. [Method]The RITSD changing of agronomic traits was studied by using 24 rice somaclonal and its donor parent under two sowing dates. [Result]The average values of RITSD were higher (over one) for the traits of pant height (PH),density of spikelets (DS),filled spikelets per panicle (FSP),spikelets per panicle (SP) and grain weight per plant (GWP),but lower for days of sowing to heading (DSH),effective panicles (EP),panicle length (PL),seed setting rate (SS) and 1 000-grain weight (1 000-GW). These showed that PH,DS,FSP,SP and GWP were easily affected by sowing date and tended to higher with the later sowing; the RITSD of somaclonal changed with the agronomic traits. The frequency of RITSD' variation of DSH and PH was higher than that of PL. The RITSD' value of EP,PL,DS,FSP,SP and SS became higher,and higher or lower for DSH and GWP in different somaclonal; compared with the donor,20 of 24 was significantly different,and the frequency of RITSD variation was over 83. 3%,however,RITSD of the most lines (75%) changed only for 1-2 characters; cluster analysis showed that the RITSD of agronomic traits belonged to different combinations of somaclonal in rice. [Conclusion]the study had provided a theoretical basis for the screening and using of the somaclonal.展开更多
In the research, four shading treatments were set, including the treatments with shading degrees at 0, 40%, 60% and 70%, in order to explore storage rate and seedling growth of annual Phoebe bournei. The results showe...In the research, four shading treatments were set, including the treatments with shading degrees at 0, 40%, 60% and 70%, in order to explore storage rate and seedling growth of annual Phoebe bournei. The results showed that the storage rate is growing upon shading degree. In the research, for example, storage rate reached the peak with the shading degree at 70%, and only 42.2% with shading degree at 0. In addition, seedling height and ground diameter showed extremely significant differences among treatments, and the treatment with shading degree at 60% was the best.展开更多
This study aimed to analyze the absorption, utilization and transfer char- acteristics of nitrogen in high-yield winter wheat (Triticum aestivum) cultivars at dif- ferent sowing dates, so as to determine the optimum...This study aimed to analyze the absorption, utilization and transfer char- acteristics of nitrogen in high-yield winter wheat (Triticum aestivum) cultivars at dif- ferent sowing dates, so as to determine the optimum sowing dates for different high-yield wheat cultivars. A field experiment was conducted in the Shajiang black soil of Anhui Province with Jimai 22, Wanrnai 52 and Zhoumai 22, and the effects of early sowing (October 3), optimum sowing (October 12) and late sowing (October 30) on wheat plant N content and accumulation, pre-and post-anthesis N accumula- tion (NA) of total plant, nitrogen remobUization to grain (NR), N remobilization effi- ciency (NRE), contribution of N remobilized to grain (NRC), grain yield, N use effi- ciency (NUE) and N harvest index (NHI) of different wheat cultivar were investigat- ed. The results showed that sowing date had an impact on N content, absorption and utilization in wheat plants at various growth stages. The NA, NR and NRC of aboveground vegetative organs of wheat before anthesis were higher than those af- ter anthesis. Under the condition of late sowing, the grain N accumulation mainly depended on the N absorption by vegetative organs before anthesis. Under the conditions of optimum and early sowing, the absorbed N after anthesis accounted for a large proportion in grain N accumulation. The N uptake intensity and relative cumulative rate differed greatly among different growth stages and different-genotype wheat cultivars, and the pre-anthesis NA, pre-anthesis NR, pre-anthesis NRE, post- anthesis N assimilation amount and post-anthesis NRC showed significant differ- ences among different wheat cultivars. The grain yields of different wheat cultivars under the early and optimum sowing were all higher than those under the late sowing. The NHI and grain N accumulation were highest under the optimum sow- ing, and the latter significantly decreased with the delay of sowing dates. In con- trast, the NUE was highest under the late sowing, reaching 35.95%-41.32%. It indi- cated that under the condition of late sowing, most of the nitrogen was not ab- sorbed by wheat, but the use efficiency of the absorbed nitrogen significantly in- creased. In overall, the three high-yield wheat cultivars were all suitable for early and optimum sowing. Under the condition of late sowing, the yield of Zhoumai 22 showed the smallest differences with those under early and optimum sowing, and its NUE was significantly improved. Therefore, among the three high-yield wheat culti- vars, Zhoumai 22 was most suitable for late sowing.展开更多
The authors had collected some cruciferous oil plants with high linolenic acid content in Sichuan Province. The result of fatty acid analysis had shown that Malcolmia africrma (L.) R. Br. and Arabis hirsuta (L.) Scop,...The authors had collected some cruciferous oil plants with high linolenic acid content in Sichuan Province. The result of fatty acid analysis had shown that Malcolmia africrma (L.) R. Br. and Arabis hirsuta (L.) Scop, have a higher linolenic acid content of 57.37% and 51.38% respectively . Thus they are worthy for further study. Descurainia sophia (L.) Webb. ex Prantl, especially that collected from Hongyuan County, has a high seed oil content of 44.17% , a linolenic acid content of 40.9 % and a high seed yield of 1 264.5 kg/hm2 . It is suggested that this oil plant species can be introduced for industrial utilization.展开更多
Wheat stripe rust has become the most dangerous disease which threaten safe yield of wheat in Sichuan Province. It is meaningful to provide technique support for integrated disease control by exploring the effective c...Wheat stripe rust has become the most dangerous disease which threaten safe yield of wheat in Sichuan Province. It is meaningful to provide technique support for integrated disease control by exploring the effective control measures of wheat stripe rust. Wheat stripe rust dynamic developments of all-planting and mixed-planting have been systematically investigated in this study by taking different mixed-planting combinations among 6 wheat varieties with different resistance levels. The results of this experiment show that the mixed-plantings of 4 and 6 wheat varieties can delay the occurance of wheat stripe rust,slow the speed of disease and decline the damage of disease as well as stabilize yield of wheats.展开更多
[Objective] This study aimed to investigate the effects of different sowing dates and sites on starch RVA profile characteristics of different ecotypes of japonica rice. [Method] Five different ecotypes of japonica ri...[Objective] This study aimed to investigate the effects of different sowing dates and sites on starch RVA profile characteristics of different ecotypes of japonica rice. [Method] Five different ecotypes of japonica rice were sown at seven different dates in four rice planting regions in Jiangsu Province to analyze the differences in starch RVA profile parameters among different rice varieties. [Result] Among eight parameters of rice starch RVA profile, peak time exhibited no significant differences among different sites, while other seven parameters varied significantly or extremely significantly among different sites, sowing dates and varieties. Specifically, rice variety exerted the most significant effects on rice starch RVA profile parameters. Starch RVA profile characteristics varied significantly among different ecological conditions but exhibited no significant differences among different latitudes. To be specific, in different sites, peak viscosity (PKV), hot paste viscosity (HPV) and breakdown viscosity (BDV) demonstrated a descending order of Huai'an 〉 Suzhou 〉 Lianyungang 〉 Yangzhou. Cool paste viscosity (CPV) and consistence viscosity (CSV) were higher in the north than in the south; specifically, CPV and CSV were significantly higher in Lianyungang and Huai'an than in Yangzhou and Suzhou. Setback viscosity (SBV) showed an increasing trend with increasing latitude; specifically, SBV was significantly lower in Suzhou than in other three sites. Pasting temperature (PAT) and peak time (PET) changed slightly among different latitudes. With the postponing of sowing date, peak viscosity (PKV), hot paste viscosity (HPV), cool paste viscosity (CPV) and peak time (PET) showed a decreasing trend, setback viscosity (SBV) and consistence viscosity (CSV) increased, breakdown viscosity (BDV) increased first and then decreased, whereas pasting temperature (PAT) decreased first and then increased. Furthermore, rice starch RVA profile parameters showed the same variation trend with sowing date in different sites; early sowing within suitable sowing dates could effectively improve the parameters of rice starch RVA profile. However, different parameters exerted different variations among different sites and most parameters were higher in the north than in the south, which indicated that starch RVA profile parameters were significantly affected by sowing date in the north of Jiangsu Province. Among eight starch RVA profile parameters, setback viscosity exhibited the maximum variation coefficient, while peak time exhibited the minimum variation coefficient. Among five rice varieties, Nanjing 46 exhibited the highest peak viscosity and breakdown viscosity and the lowest setback viscosity and consistence viscosity, suggesting that Nanjing 46 had the most appropriate starch RVA profile characteristics and the best cooking and eating quality. Lianjing 4 exhibited relatively high peak viscosity and breakdown viscosity, and relatively low setback viscosity and consistence viscosity, suggesting that Lianjing 4 had good starch RVA profile characteristics. Different sowing dates and sites exerted significant effects on starch RVA profiles of different eco- types of japonica rice. Rice starch RVA profile characteristics varied significantly among different sites but exhibited no significant variations among different latitudes. In addition, starch RVA profile characteristics varied significantly among different sowing dates. Therefore, early sowing of the same variety was conducive to improving starch RVA profile characteristics in appropriate planting regions. [Conclusion] This study provided a theoretical basis for producing high-quality rice and improving the eating quality of rice in Jiangsu Province.展开更多
In order to investigate the effects of seed rate on root twining power and seedling quality of machine-transplanted super rice cultivars, Yongyou 12 and Zhongzheyou No.l, total 6 seed rates were arranged, and the grow...In order to investigate the effects of seed rate on root twining power and seedling quality of machine-transplanted super rice cultivars, Yongyou 12 and Zhongzheyou No.l, total 6 seed rates were arranged, and the growth characteris- tics, quality and root twining power of machine-transplanted rice seedlings were studied. The results showed that seed rate had great effects on root twining power and qualityof rice seedlings; with the increase of seed rate, the root twining power of rice seedlings was increased, but the quality of rice seedlings was significantly reduced; under the condition of high seed rate, rice seedlings were weak with less accumulate dry matter and nonuniform growth, and the proportion of weak seedlings was higher. When the seed rate of both rice cultivars was reduced by 10 g/tray, the average seedling height was increased by 0.5 cm, leaf age was increased by 0.1, stem base diameter was increased by 0.1 cm, and root number per plant was increased by 0.3. When the seed rate was increased by 10 g/tray, the accumulated dry matter per plant was reduced by 5.1 mg. With the increase of seed rate, the seedling quality of Zhongzheyou No.1 was decreased rapidly, and the proportion of weak seedlings was increased rapidly. However, Yongyou 12 has a larger elasticity in seed rate. When the seed rate reached to 50 g/tray, blanket seedlings of Yongy- ou 12 were nursed with uniform growth and higher quality, but the shoots were sparse with lower leaf area index. However, when the seed rate was up to 50 g/tray, blanket seedlings of Zhongzheyou No.1 were nursed with uniform growth and higher quality, as well as higher-density shoots. From a comprehensive point of view, the optimum seed rates of Yongyou 12 and Zhongzheyou No.1 were 65 and 50 g/tray, respectively.展开更多
基金supported by the National Natural Science Foundation of China(72171219,72201264,71921001,71801206,71971203)the Fundamental Research Funds for the Central Universities(WK2040000027)+1 种基金the New Liberal Arts Fund of USTC(FSSF-A-230104)the Four Batch Talent Programs of China.
文摘The booming live-streaming commerce has significantly changed the traditional e-commerce model,thus attracting much attention from both industry and academia.In recent years,an increasing number of scholars have applied analytical models to explore live-streaming strategies for firms in different scenarios.However,the previous literature mainly considers monopolists,while in the real world,competition is not rare.To fill this gap between the literature and practical observations,this paper applies a game theoretical model to study live-streaming adoption and pricing strategy for firms under competitive environments.The results show that,for competitive firms,the equilibrium strategy depends on the relation between the commission rate and the intensity of the market expansion effect.Additionally,compared to the case in which no firm adopts live-streaming,competitive firms do not always benefit from the adoption of live-streaming selling.The paper also shows that competition plays a negative role in inducing a firm to adopt live-streaming.
文摘This study considers an-particle jump-diffusion system with mean field interaction,where the coefficients are locally Lipschitz continuous.We address the convergence as n→∞of the empirical measure of the jump-diffusions to the solution of a deterministic McKean-Vlasov equation.The strong well-posedness of the associated McKean-Vlasov equation and a corresponding propagation of chaos result are proven.In particular,we also provide precise estimates of the convergence speed with respect to a Wasserstein-like metric.
文摘In the era of network live broadcasting for everyone,the development of live broadcasting platforms is also more intelligent and diversified.However,in the face of a large group of elderly users,the interface interaction design mode used is still mainly based on the interaction mode for young groups,and is not designed for elderly users.Therefore,a design method for optimizing the interaction interface of live broadcasting platform for elderly users was proposed in this study.Firstly,the case study method and Delphi expert survey method were used to determine the design needs of elderly users and the design mode was analysed.Secondly,the orthogonal design principle was used to design a test sample of the interactive interface of live broadcasting platform applicable for the elderly users,and then a user evaluation system was established to calculate the weights of the design elements using hierarchical analysis,and then the predictive relationship between the design mode of the interactive interface of live broadcasting platform and the elderly users was established by Quantitative Theory I.Finally,Genetic Algorithm was applied to generate the optimized design scheme.The results showed that the design method based on the Genetic Algorithm and the combination of Quantitative Theory can scientifically and effectively optimize the design of the interactive interface of the live broadcasting platform for the elderly users,and improve the experience of the elderly users.
文摘The hot compression tests of 7Mo super austenitic stainless(SASS)were conducted to obtain flow curves at the temperature of 1000-1200℃and strain rate of 0.001 s^(-1)to 1 s^(-1).To predict the non-linear hot deformation behaviors of the steel,back propagation-artificial neural network(BP-ANN)with 16×8×8 hidden layer neurons was proposed.The predictability of the ANN model is evaluated according to the distribution of mean absolute error(MAE)and relative error.The relative error of 85%data for the BP-ANN model is among±5%while only 42.5%data predicted by the Arrhenius constitutive equation is in this range.Especially,at high strain rate and low temperature,the MAE of the ANN model is 2.49%,which has decreases for 18.78%,compared with conventional Arrhenius constitutive equation.
文摘As mobility and migration become the norm,citizens in modern cities live among people who remain strangers to each other.This creates new opportunities and challenges for urban social life.Public space is a critical forum in which strangers encounter each other and have the opportunity to develop social protocols for coexisting in diversity.New media technologies have huge impact on the form and quality of public space.Digital art can create experimental public spaces in which mediated connections and embodied presence are combined in new ways.Through the practice and research of digital art,we can imagine a communicative city in which urban digital media is less about spectacle,and more about promoting new forms of public speech and social encounter between people.
基金Supported by the Special Funds for Agro-scientific Research in the Public Interest (201003016 201203029)Special Fund for the Industrial Technology System Construction of Modern Agriculture (CARS-01-04A)~~
文摘[Objective] This paper aimed to clarify the rice planting methods and its supporting technology to be developed in rice producing areas in China. [Method] Evolvement of rice planting methods in rice producing areas in China and in representative rice-growth countries abroad, its characteristics, adaptability and key issues were analyzed. [Result] The analysis of development of rice planting method in China and abroad indicated that rice planting method was adapted to rice-based cropping system and ecological environment, and its transition accompanied with social and economic development. With agricultural labor transfer from agriculture to other industries since 1990’s, rice seedling throwing was gradually applied and in recent decades, while direct seeding and machine transplanting were practiced. Now, hand transplanting is still the main rice planting method, adopted in 50% of national rice planting area; seedling throwing, direct seeding and machine transplanting are conducted in 25% , 12% and 13% of the national rice planting area. [Conclusion] Machine transplanting should be a leading rice planting method. Though area covered with machine direct seeding is still small up to now, it can be practiced in some rice growing area due to labor saving and low cost. Leading planting methods and its supporting key technologies are proposed in various rice producing areas in the future.
基金supported by NSFC(Nos.41274120,41404085,and 41504084)
文摘3D traveltime calculation is widely used in seismic exploration technologies such as seismic migration and tomography. The fast marching method (FMM) is useful for calculating 3D traveltime and has proven to be efficient and stable. However, it has low calculation accuracy near the source, which thus gives it low overall accuracy. This paper proposes a joint traveltime calculation method to solve this problem. The method firstly employs the wavefront construction method (WFC), which has a higher calculation accuracy than FMM in calculating traveltime in the small area near the source, and secondly adopts FMM to calculate traveltime for the remaining grid nodes. Due to the increase in calculation precision of grid nodes near the source, this new algorithm is shown to have good calculation precision while maintaining the high calculation efficiency of FMM, which is employed in most of the computational area. Results are verified using various numerical models.
基金Supported by National Natural Science Foundation of China(31371562,31301276)Special Fund for Fundamental Scientific Research Business of Central Public Research Institutes(Agriculture)(201103003+2 种基金201203079)Key Projects in the National Science&Technology Pillar Program during the 12thFive-year Plan Period(2012BAD04B08)Fund for Independent Innovation of Agricultural Sciences in Jiangsu Province(CX(14)5021)~~
文摘[Objective] This study aimed to investigate the effect of direct-seeding with non-flooding and wheat residue returning patterns on greenhouse gas emission from rice paddy. [Method] Two rice cultivars currently used in the production, Yangdao 6 (an indica) and Yangjing 4038 (a japonica), were field grown using a direct-seeding method, and four treatments, wheat straw incorporation into soil and traditional flooding (SlF), non-flooding and wheat straw mulching (NSM), non-flooding and wheat straw incorporation into soil (NSl) and traditional flooding (no straw returned, Control, TF), were imposed after sowing to maturity. Effects of direct-seeding with non-flooding and wheat residue returning patterns on CH4, N20 and CO2 emissions were investigated by using the method of static chamber-gas chromatographic tech- niques. [Result] Grain yield showed no significant difference between non-flooding and flooding treatments, but was significantly higher under the SlF than under any other treatments. The emission flux of CH4 and CO2 under TF and SlF exhibited a single peak curve, while changed little under the NSl and NSM The emission flux of N2Oshowed multiple perk curves for all the treatments. Compared with TF, SlF significantly increased mean emission flux of CH4 or N2O, decreased emission of N20, while NSl and NSM significantly decreased the mean emission flux of OH4, and increased emission flux of N2O and CO2. SIF also increased Green Warm Potential (GWP) of CH4, N2O and CO2 and the GWP per unit grain yield by 47.3%- 53.7% and 32.2%-39.4%, respectively. Both NSl and NSM decreased GWP by 24.2%-29.6% and 30.1%-35.5%, and the GWP per unit grain yield was decreased by 21.7-27.2% and 25.6%-31.1%, respectively. [Conelusion] both NSl and NSM could significantly reduce greenhouse effect of CH4, N2O and CO2 meanwhile maintain a high grain yield.
文摘In order to study the effect of rice straw returning and seeding patterns on seedling emergence and grain yield, field experiment was conducted to investi- gate the effects of straw mechanized returning and different seeding patterns on e- mergence rate, emergence uniformity and yield traits of wheat after rice. The results were as follows: in rice straw removal treatments, the emergence rate of mechani- cal seeding in drill was lower than that of mechanical uniform planting and manual broadcast sowing, which were 51.84%, 90.89% and 88.87%, respectively; the emer- gence uniformity of manual broadcast sowing was inferior to mechanical seeding in drill and mechanical uniform planting, which were 0.49, 0.26 and 0.23, respectively. As for the treatments with rice straw returning to the field, the emergence rate and emergence uniformity all decreased in the three seeding patterns, of which mechan- ical seeding in drill dropped markedly with emergence rate decreased by 36.54%. The emergence rate and emergence uniformity affected grain yield by affecting pan- icle, grains per spike and 1 000-grain weight. The grain yield for the treatment with rice straw removal was 6 091.34 kg/hm2, while that with rice straw returning to field was 6 476.20 kg/hm2, and both were higher than the yields of the other two seed- ing patterns. Therefore, mechanical uniform planting was?recommended for its higher emergence rate, better emergence uniformity, which was conductive to increase grain yield in wheat after rice production with rice straw returning to field.
基金Supported by Central Financial Forestry Science and Technology Promotion project([2014]XT003)~~
文摘This study was conducted for the purposes of reducing consumption of wild resources of Paris polyphylla Smith, satisfying the market demand, saving the production cost, improving utilization rate of forest land, increasing income of foresters and protecting ecological environment. Three types of fores{ land, i.e., the evergreen forest land (China fir forest), deciduous forest land (walnut forest) and shrub land (honey suckle forest.) were selected, and seeds and cut rhizomes of Paris polyphylla Smith produced in Bamian Mountain, Hunan, were used in the study on understory seedling raising and cultivation techniques. The results showed that: when using different propagation materials, seed propagation could be adopted to reduce the consumption of wild resources and provide a large number of seedlings, and was beneficial to large-scale planting; and when conducing seedling and plantlet raising followed by transplanting and direct seeding and planting using different propagation materials in large-scale understory cultivation, direct seeding/ planting was appropriate for saving save production cost with the advantage of early production. Among the 3 different types of forest land, the best choice was broad- leaved forest land, which could achieve better economic benefit because of con- forming with the ecological habit and growth and development law of Paris poly- phylla Smith.
基金Supported by Chongqing Major Research Project "Innovation in Hybrid Rice Breeding and New Materials" ( CSTC, 2007, AA1019 )Sichuan Province Breeding Research Project (06yzgg-01)~~
文摘[Objective]The aim was to study the sensitive response characteristics of the main agronomic traits of somaclonal and the variation of sensitive response of the lines of somaclonal to sowing date. [Method]The RITSD changing of agronomic traits was studied by using 24 rice somaclonal and its donor parent under two sowing dates. [Result]The average values of RITSD were higher (over one) for the traits of pant height (PH),density of spikelets (DS),filled spikelets per panicle (FSP),spikelets per panicle (SP) and grain weight per plant (GWP),but lower for days of sowing to heading (DSH),effective panicles (EP),panicle length (PL),seed setting rate (SS) and 1 000-grain weight (1 000-GW). These showed that PH,DS,FSP,SP and GWP were easily affected by sowing date and tended to higher with the later sowing; the RITSD of somaclonal changed with the agronomic traits. The frequency of RITSD' variation of DSH and PH was higher than that of PL. The RITSD' value of EP,PL,DS,FSP,SP and SS became higher,and higher or lower for DSH and GWP in different somaclonal; compared with the donor,20 of 24 was significantly different,and the frequency of RITSD variation was over 83. 3%,however,RITSD of the most lines (75%) changed only for 1-2 characters; cluster analysis showed that the RITSD of agronomic traits belonged to different combinations of somaclonal in rice. [Conclusion]the study had provided a theoretical basis for the screening and using of the somaclonal.
基金Supported by Forestry Science and Technology Project of Hunan Province(XLK201406)~~
文摘In the research, four shading treatments were set, including the treatments with shading degrees at 0, 40%, 60% and 70%, in order to explore storage rate and seedling growth of annual Phoebe bournei. The results showed that the storage rate is growing upon shading degree. In the research, for example, storage rate reached the peak with the shading degree at 70%, and only 42.2% with shading degree at 0. In addition, seedling height and ground diameter showed extremely significant differences among treatments, and the treatment with shading degree at 60% was the best.
基金Supported by National Key Technology Research and Development Program(2012BAD04B09,2013BAD07B08)
文摘This study aimed to analyze the absorption, utilization and transfer char- acteristics of nitrogen in high-yield winter wheat (Triticum aestivum) cultivars at dif- ferent sowing dates, so as to determine the optimum sowing dates for different high-yield wheat cultivars. A field experiment was conducted in the Shajiang black soil of Anhui Province with Jimai 22, Wanrnai 52 and Zhoumai 22, and the effects of early sowing (October 3), optimum sowing (October 12) and late sowing (October 30) on wheat plant N content and accumulation, pre-and post-anthesis N accumula- tion (NA) of total plant, nitrogen remobUization to grain (NR), N remobilization effi- ciency (NRE), contribution of N remobilized to grain (NRC), grain yield, N use effi- ciency (NUE) and N harvest index (NHI) of different wheat cultivar were investigat- ed. The results showed that sowing date had an impact on N content, absorption and utilization in wheat plants at various growth stages. The NA, NR and NRC of aboveground vegetative organs of wheat before anthesis were higher than those af- ter anthesis. Under the condition of late sowing, the grain N accumulation mainly depended on the N absorption by vegetative organs before anthesis. Under the conditions of optimum and early sowing, the absorbed N after anthesis accounted for a large proportion in grain N accumulation. The N uptake intensity and relative cumulative rate differed greatly among different growth stages and different-genotype wheat cultivars, and the pre-anthesis NA, pre-anthesis NR, pre-anthesis NRE, post- anthesis N assimilation amount and post-anthesis NRC showed significant differ- ences among different wheat cultivars. The grain yields of different wheat cultivars under the early and optimum sowing were all higher than those under the late sowing. The NHI and grain N accumulation were highest under the optimum sow- ing, and the latter significantly decreased with the delay of sowing dates. In con- trast, the NUE was highest under the late sowing, reaching 35.95%-41.32%. It indi- cated that under the condition of late sowing, most of the nitrogen was not ab- sorbed by wheat, but the use efficiency of the absorbed nitrogen significantly in- creased. In overall, the three high-yield wheat cultivars were all suitable for early and optimum sowing. Under the condition of late sowing, the yield of Zhoumai 22 showed the smallest differences with those under early and optimum sowing, and its NUE was significantly improved. Therefore, among the three high-yield wheat culti- vars, Zhoumai 22 was most suitable for late sowing.
文摘The authors had collected some cruciferous oil plants with high linolenic acid content in Sichuan Province. The result of fatty acid analysis had shown that Malcolmia africrma (L.) R. Br. and Arabis hirsuta (L.) Scop, have a higher linolenic acid content of 57.37% and 51.38% respectively . Thus they are worthy for further study. Descurainia sophia (L.) Webb. ex Prantl, especially that collected from Hongyuan County, has a high seed oil content of 44.17% , a linolenic acid content of 40.9 % and a high seed yield of 1 264.5 kg/hm2 . It is suggested that this oil plant species can be introduced for industrial utilization.
文摘Wheat stripe rust has become the most dangerous disease which threaten safe yield of wheat in Sichuan Province. It is meaningful to provide technique support for integrated disease control by exploring the effective control measures of wheat stripe rust. Wheat stripe rust dynamic developments of all-planting and mixed-planting have been systematically investigated in this study by taking different mixed-planting combinations among 6 wheat varieties with different resistance levels. The results of this experiment show that the mixed-plantings of 4 and 6 wheat varieties can delay the occurance of wheat stripe rust,slow the speed of disease and decline the damage of disease as well as stabilize yield of wheats.
文摘[Objective] This study aimed to investigate the effects of different sowing dates and sites on starch RVA profile characteristics of different ecotypes of japonica rice. [Method] Five different ecotypes of japonica rice were sown at seven different dates in four rice planting regions in Jiangsu Province to analyze the differences in starch RVA profile parameters among different rice varieties. [Result] Among eight parameters of rice starch RVA profile, peak time exhibited no significant differences among different sites, while other seven parameters varied significantly or extremely significantly among different sites, sowing dates and varieties. Specifically, rice variety exerted the most significant effects on rice starch RVA profile parameters. Starch RVA profile characteristics varied significantly among different ecological conditions but exhibited no significant differences among different latitudes. To be specific, in different sites, peak viscosity (PKV), hot paste viscosity (HPV) and breakdown viscosity (BDV) demonstrated a descending order of Huai'an 〉 Suzhou 〉 Lianyungang 〉 Yangzhou. Cool paste viscosity (CPV) and consistence viscosity (CSV) were higher in the north than in the south; specifically, CPV and CSV were significantly higher in Lianyungang and Huai'an than in Yangzhou and Suzhou. Setback viscosity (SBV) showed an increasing trend with increasing latitude; specifically, SBV was significantly lower in Suzhou than in other three sites. Pasting temperature (PAT) and peak time (PET) changed slightly among different latitudes. With the postponing of sowing date, peak viscosity (PKV), hot paste viscosity (HPV), cool paste viscosity (CPV) and peak time (PET) showed a decreasing trend, setback viscosity (SBV) and consistence viscosity (CSV) increased, breakdown viscosity (BDV) increased first and then decreased, whereas pasting temperature (PAT) decreased first and then increased. Furthermore, rice starch RVA profile parameters showed the same variation trend with sowing date in different sites; early sowing within suitable sowing dates could effectively improve the parameters of rice starch RVA profile. However, different parameters exerted different variations among different sites and most parameters were higher in the north than in the south, which indicated that starch RVA profile parameters were significantly affected by sowing date in the north of Jiangsu Province. Among eight starch RVA profile parameters, setback viscosity exhibited the maximum variation coefficient, while peak time exhibited the minimum variation coefficient. Among five rice varieties, Nanjing 46 exhibited the highest peak viscosity and breakdown viscosity and the lowest setback viscosity and consistence viscosity, suggesting that Nanjing 46 had the most appropriate starch RVA profile characteristics and the best cooking and eating quality. Lianjing 4 exhibited relatively high peak viscosity and breakdown viscosity, and relatively low setback viscosity and consistence viscosity, suggesting that Lianjing 4 had good starch RVA profile characteristics. Different sowing dates and sites exerted significant effects on starch RVA profiles of different eco- types of japonica rice. Rice starch RVA profile characteristics varied significantly among different sites but exhibited no significant variations among different latitudes. In addition, starch RVA profile characteristics varied significantly among different sowing dates. Therefore, early sowing of the same variety was conducive to improving starch RVA profile characteristics in appropriate planting regions. [Conclusion] This study provided a theoretical basis for producing high-quality rice and improving the eating quality of rice in Jiangsu Province.
基金Supported by National Rice Industry Technology System(CARS-01-04A)National Key Technology Research and Development Program(2012BAD07B02)+1 种基金Ministry of Science and Technology’s Special Fund for Technology Development and Research of Research Institutes(2013EG134237)National Nonprofit Institute Research Grant of CATAS-TCGRI(2012RG005-3)~~
文摘In order to investigate the effects of seed rate on root twining power and seedling quality of machine-transplanted super rice cultivars, Yongyou 12 and Zhongzheyou No.l, total 6 seed rates were arranged, and the growth characteris- tics, quality and root twining power of machine-transplanted rice seedlings were studied. The results showed that seed rate had great effects on root twining power and qualityof rice seedlings; with the increase of seed rate, the root twining power of rice seedlings was increased, but the quality of rice seedlings was significantly reduced; under the condition of high seed rate, rice seedlings were weak with less accumulate dry matter and nonuniform growth, and the proportion of weak seedlings was higher. When the seed rate of both rice cultivars was reduced by 10 g/tray, the average seedling height was increased by 0.5 cm, leaf age was increased by 0.1, stem base diameter was increased by 0.1 cm, and root number per plant was increased by 0.3. When the seed rate was increased by 10 g/tray, the accumulated dry matter per plant was reduced by 5.1 mg. With the increase of seed rate, the seedling quality of Zhongzheyou No.1 was decreased rapidly, and the proportion of weak seedlings was increased rapidly. However, Yongyou 12 has a larger elasticity in seed rate. When the seed rate reached to 50 g/tray, blanket seedlings of Yongy- ou 12 were nursed with uniform growth and higher quality, but the shoots were sparse with lower leaf area index. However, when the seed rate was up to 50 g/tray, blanket seedlings of Zhongzheyou No.1 were nursed with uniform growth and higher quality, as well as higher-density shoots. From a comprehensive point of view, the optimum seed rates of Yongyou 12 and Zhongzheyou No.1 were 65 and 50 g/tray, respectively.