Cuban President Fidel Castro highly praised the products of Zhangjiakou’s Xuanhua Building Machinery Plant at a national conference in 1990. On the president’s recommendations, the Cuban ambassador to China conducte...Cuban President Fidel Castro highly praised the products of Zhangjiakou’s Xuanhua Building Machinery Plant at a national conference in 1990. On the president’s recommendations, the Cuban ambassador to China conducted an on-the-spot investigation and expressed his appreciation of the plant’s products. Besides Cuba, the plant’s products also enjoy a high reputation among customers in Pakistan, Chile, Australia, Papua New Guinea, Ghana and Southeast Asia. Zhangjiakou had its展开更多
An automated method based on the curve chain was proposed for dimensioning of engineering drawings for the mechanical products.According to the internal relation between the features of 3D model feature and elements o...An automated method based on the curve chain was proposed for dimensioning of engineering drawings for the mechanical products.According to the internal relation between the features of 3D model feature and elements of 2D drawing,the curve chain was established to reflect the geometric topological structure between the elements.It divides the dimensions into the absolute dimensions within the cure chain and the relative dimensions between the curve chains.The parallel and lengthy relationship between the drawing elements of the constructed X and Y parallel matrix was solved to remove redundant elements in the curve chain and labeled the absolute dimensions of the remaining valid elements.The average minimum weight coefficient was introduced to judge the dependence on the relative dimensions between curve chains.Through the analysis of the overlap between the circular rectangular areas,including all the absolute dimensions of the curve chains,overlapping curve chains were merged,and their dimensions were rearranged to avoid the cross interference between them.The method was seamlessly integrated into the drafting module of product design software NX,and it developed an automated dimensioning system.The examples show that the system has excellent interactivity and robustness in the dimensioning of product engineering drawings.The dimension information is complete,accurate and reliable.展开更多
The model for forecasting the test data on mechanical products is established in the application of the grey system theories. A new formula of the background value is introduced into the model. The result of an exampl...The model for forecasting the test data on mechanical products is established in the application of the grey system theories. A new formula of the background value is introduced into the model. The result of an example shows the method can reduce test expense and enhance the precision of forecasting.展开更多
Since the launch of the economic reform and opening to the outside world, China has seen rapid growth in its export of mechanical and electrical products, with its export
Zhejiang’s machine-building industryhas made sustained efforts to increase itsexports through the combination ofindustry and trade. In the past decade,Zhejiang’s export volume of mechanicaland electrical products ha...Zhejiang’s machine-building industryhas made sustained efforts to increase itsexports through the combination ofindustry and trade. In the past decade,Zhejiang’s export volume of mechanicaland electrical products has increased over 10times, becoming the leading exports fromthe province. Zhejiang has thereforebecome an important province exportingmachinery in China.展开更多
The Measures for the Administration of the Import of Mechanical and Electronic' Products co-formulated by the Ministry of Commerce,the General Administration of Customs and the General Administration of Quality Su...The Measures for the Administration of the Import of Mechanical and Electronic' Products co-formulated by the Ministry of Commerce,the General Administration of Customs and the General Administration of Quality Supervision,Inspection and Quarantine,was hereby promul- gated,which entered into force as of May 1,2008.展开更多
Factors leading to rise of prices of agricultural products mainly include tension of supply-demand relationship,promotion of production cost and circulation cost,and speculation of Refugee Capital(Hot Money).Factors l...Factors leading to rise of prices of agricultural products mainly include tension of supply-demand relationship,promotion of production cost and circulation cost,and speculation of Refugee Capital(Hot Money).Factors leading to low price and difficult sales of agricultural products mainly include asymmetry of supply-demand information,lack of risk management tools for prices of agricultural products and decentralized and small-scaled operation of farmers.On the basis of these factors,this paper presents following countermeasures and suggestions for stabilizing prices of agricultural products:firstly,building long-effect mechanism for production and sales of agricultural products;secondly,expand the production and increase supply of agricultural products;thirdly,control the rising range of production cost for agricultural products;fourthly,enhance organization level of farmers;fifthly,promote innovation and development of risk management tools for prices of agricultural products.展开更多
Aiming at the four issues of underground storage state,exploitation mechanism,crude oil flow and efficient recovery,the key theoretical and technical issues and countermeasures for effective development of Gulong shal...Aiming at the four issues of underground storage state,exploitation mechanism,crude oil flow and efficient recovery,the key theoretical and technical issues and countermeasures for effective development of Gulong shale oil are put forward.Through key exploration and research on fluid occurrence,fluid phase change,exploitation mechanism,oil start-up mechanism,flow regime/pattern,exploitation mode and enhanced oil recovery(EOR)of shale reservoirs with different storage spaces,multi-scale occurrence states of shale oil and phase behavior of fluid in nano confined space were provided,the multi-phase,multi-scale flow mode and production mechanism with hydraulic fracture-shale bedding fracture-matrix infiltration as the core was clarified,and a multi-scale flow mathematical model and recoverable reserves evaluation method were preliminarily established.The feasibility of development mode with early energy replenishment and recovery factor of 3o%was discussed.Based on these,the researches of key theories and technologies for effective development of Gulong shale oil are proposed to focus on:(1)in-situ sampling and non-destructive testing of core and fluid;(2)high-temperature,high-pressure,nano-scale laboratory simulation experiment;(3)fusion of multi-scale multi-flow regime numerical simulation technology and large-scale application software;(4)waterless(CO_(2))fracturing technique and the fracturing technique for increasing the vertical fracture height;(5)early energy replenishment to enhance oil recovery;(6)lifecycle technical and economic evaluation.Moreover,a series of exploitation tests should be performed on site as soon as possible to verify the theoretical understanding,optimize the exploitation mode,form supporting technologies,and provide a generalizable development model,thereby supporting and guiding the effective development and production of Gulong shale oil.展开更多
Reservoirs characterized by high temperature,high-pressure,medium high cementation strength,low porosity,and low permeability,in general,are not affected by sand production issues.Since 2009,however,it is known that c...Reservoirs characterized by high temperature,high-pressure,medium high cementation strength,low porosity,and low permeability,in general,are not affected by sand production issues.Since 2009,however,it is known that cases exists where sand is present and may represent a significant technical problem(e.g.,the the Dina II condensate gas field).In the present study,the main factors affecting sand production in this type of reservoir are considered(mechanical properties,stress fields,production system,completion method and gas flow pattern changes during the production process).On this basis,a new liquid-solid coupled porous elasto-plastic 3D sand production model is introduced and validated through comparison with effective sand production data.The related prediction errors are found to be within 15%,which represents the necessary prerequisite for the utilization of such a model for the elaboration of sand prevention measures.展开更多
[Objectives]To study the breeding of a new sugarcane variety Yuetang 08776 suitable for mechanized production.[Methods]With Yuetang 96-86 as the female parent and Yuetang 99-66 as the male parent,Yuetang 08776 was bre...[Objectives]To study the breeding of a new sugarcane variety Yuetang 08776 suitable for mechanized production.[Methods]With Yuetang 96-86 as the female parent and Yuetang 99-66 as the male parent,Yuetang 08776 was bred by the Bioengineering Institute of Guangdong Academy of Sciences.It was approved as a non-major crop variety by the Ministry of Agriculture and Rural Affairs in December,2019.Through many years of multi-pilot trials,the characters,traits and disease resistance of Yuetang 08776 were investigated,and the key points of its cultivation technique were summarized.[Results]Yuetang 08776 is characterized by medium maturity,high sugar content,high and stable yield,strong cold and drought resistance,large number of effective stems,strong ratooning ability and lodging resistance.Yuetang 08776 has excellent agronomic traits,and has been identified as moderately resistant to smut and mosaic disease.The average cane yield of Yuetang 08776 was 119.89 t/ha,18.50 t/ha higher than that of CK,an increase of 18.25%.The average sugar yield was 17.15,2.11 t/ha higher than that of CK,an increase of 14.03%.The average sucrose content of Yuetang 08776 in the early period(November to December)was 13.20%,0.71 percentage points lower than that of CK;in the middle and late period(January to March of the following year),the average sucrose content was 15.23%,0.22 percentage points lower than that of CK;and the average sucrose content of the whole period was 14.21%,0.47 percentage points lower than that of CK.[Conclusions]Yuetang 08776 is a sugarcane variety with medium maturity,high sugar,high and stable yield,strong resistance and good ratooning.It is suitable for mechanized seeding,management and harvesting,and suitable for planting and popularizing in most sugarcane production areas of Guangdong,Guangxi and Yunnan.展开更多
The main technical content of full mechanized corn production in Daiyue District is explained,and the problems of disease and insect pest control in the middle and late growth stage of corn in full mechanized producti...The main technical content of full mechanized corn production in Daiyue District is explained,and the problems of disease and insect pest control in the middle and late growth stage of corn in full mechanized production are analyzed."One prevention double reduction"of corn performed by unmanned aerial vehicle(UAV)and self-propelled sprayer is compared and analyzed,and some suggestions are put forward for further popularization and application of full mechanized corn production.展开更多
[Objectives] This study was conducted to explore the effect of machine harvesting on ratooning ability of Guitang 47, and to provide basis for mechanized production of Guitang 47. [Methods] On the basis of mechanized ...[Objectives] This study was conducted to explore the effect of machine harvesting on ratooning ability of Guitang 47, and to provide basis for mechanized production of Guitang 47. [Methods] On the basis of mechanized planting and management of newly planted sugarcane Guitang 47, a comparative test of machine harvesting and manual harvesting was conducted, during which the plant generation rate, sugarcane yield, sucrose content and related agronomic traits of ratoon cane were continuously investigated in two years after machine harvesting of the newly planted sugarcane. [Results] There were no significant differences in the plant generation rate, plant height, stalk diameter, millable cane, sugarcane yield and sucrose content from manual harvesting of Guitang 47 in the first and second years after machine harvesting. In the second year after machine harvesting, the yields of ratoon cane and the sugar content reached 101.70 and 15.32 t/hm^2, respectively, which were equivalent to those of manual harvesting. [Conclusions] Guitang 47 has strong ratooning ability and lodging resistance and strong resistance to rolling and crushing, and is adaptive to full mechanized production. It should be promoted and accelerated in sugarcane areas lacking labor to reduce costs and increase benefits.展开更多
The intrinsic product polarization and intramolecular isotope effect of the S(~1D,~3P) + HD reaction have been investigated on both the lowest singlet state(1A) and the triplet state(3A and 3A) potential energy...The intrinsic product polarization and intramolecular isotope effect of the S(~1D,~3P) + HD reaction have been investigated on both the lowest singlet state(1A) and the triplet state(3A and 3A) potential energy surfaces by using quasi-classical trajectory and quantum mechanical methods.The calculations indicate that intramolecular isotope effects are different on the three electronic states.The stereodynamics study shows that the P(θr) distributions,P(φ r) distributions,and polarization-dependent differential cross sections(PDDCSs)(00) are sensitive to mass factor and the product angular momentum vectors are not only aligned but also oriented.展开更多
Poor bioavailability and undefined major/direct targets are two major obstacles for herbal medicines and natural products(NPs) to elucidate their precise mechanisms in vivo. Gut microbiota is an important bridge bet...Poor bioavailability and undefined major/direct targets are two major obstacles for herbal medicines and natural products(NPs) to elucidate their precise mechanisms in vivo. Gut microbiota is an important bridge between eukayotic body and environment, which can interact with a majority of medicines with poor bioavailability and mediate their in vivo pharmacological activities. There are two main modes through which gut microbiota may mediate the pharmacological effects of NPs. First, gut microbiota catabolizes the NPs in herbal medicines into secondary metabolites with higher bioavialability and/or higher activity, facilitating the NPs enter circulation and exert beneficial impact at the pathological spot. Second, herbal medicines and NPs can favorably shift the compositional structure of gut microbiota, thereby performing remote functions to diseased organs/tissues via the systemic impaction of gut microbiota. In this review, the potential pathways were summarized through which gut microbes facilitate the pharmacological functions of herbal medicines and NPs and highlight the significance of gut microbiota in clarifying the in vivo mechanisms of herbal medicines and NPs.展开更多
Nitrous oxide(N2O)is one of the significant greenhouse gases,and partial nitritation-anammox(PNA)process emits higher N2O than traditional nitrogen removal processes.N2O production in PNA mainly occurs in three differ...Nitrous oxide(N2O)is one of the significant greenhouse gases,and partial nitritation-anammox(PNA)process emits higher N2O than traditional nitrogen removal processes.N2O production in PNA mainly occurs in three different pathways,i.e.,the ammonia oxidizing bacteria(AOB)denitrification,the hydroxylamine(NH2 OH)oxidation and heterotrophic denitrifiers denitrification.N2O emission data vary significantly because of the different operational conditions,bioreactor configurations,monitoring systems and quantitative methods.Under the common operational parameter scopes of PNA,N2O emission via NH2 OH oxidation dominates at relatively low dissolved oxygen(DO),low inorganic carbon(IC),high pH or low N02-concentration,while N2O emission via AOB denitrification dominates at relative higher DO,higher IC.lower pH or higher N2O-concentration.AOB are highly enriched while nitriteoxidizing bacteria(NOB)are rarely found in partial nitritation process,and the order Nitrosomonadales of AOB is the dominant group and N2O producer.Anammox bacteria,AOB and certain amount of heterotrophic denitrifying bacteria are observed in the anammox process,the genus Denitratisoma and the heterotrophic denitrifying bacteria in the deep layer of anammox granules are the dominant N2O generation bacteria.In one-stage PNA reactors,anammox bacteria account for a large fraction of the biomass,AOB account for small portion,and NOB account for even less.The microbial community,diversity and N2O producers in one-stage PNA reactors are similar with those in two-stage PNA reactors.The dominant anammox bacteria,AOB and NOB in PNA are the species Candidatus Brocadia,the genera of Nitrotoga,Nitrospira and Nitrobacter,and the genus Nitrosomonas,respectively.The relations between N2O emission pathways and microbial communities need further study in the future.展开更多
Northern pike is regarded as a specialist in swimming acceleration. The force production mechanism of northern pike, Esox lucius, during its predation S-starts was numerically studied in this article. The problem was ...Northern pike is regarded as a specialist in swimming acceleration. The force production mechanism of northern pike, Esox lucius, during its predation S-starts was numerically studied in this article. The problem was reasonably simplified to a loose-coupling problem of fish swimming dynamics and hydrodynamics just in the swimming direction. The approach involved the simulation of the flow by solving the two-dimensional unsteady incompressible Navier-Stokes equations and decribing the fish motion dynamics based on Newton's Second Law. Visualizations of flow fields and vortex structures were performed. The results show that the large acceleration is obtained mainly in the first undulatory cycle in which the amplitude increases. In the second cycle, a couple of vortices are generated and induce a jet. In the third cycle, the jet is strengthened by the mergence of the vortices in the same direction. Through discussing the effects of various controllable factors on the swimming performance, it is found that the actual locomotion mode of the northern pike in nature is just the best choice.展开更多
The surprising thing is that arising almost 50 years ago from the linear sigma model (LSM) with spontaneously broken chiral symmetry, the light scalar meson problem has become central in the nonperturbative quantum ...The surprising thing is that arising almost 50 years ago from the linear sigma model (LSM) with spontaneously broken chiral symmetry, the light scalar meson problem has become central in the nonperturbative quantum chromodynamics (QCD) for it has been made clear that LSM could be the low energy realization of QCD. First we review briefly signs of four-quark nature of light scalars. Then we show that the light scalars are produced in the two photon collisions via four-quark transitions in contrast to the classic P wave tensor qq mesons that are produced via two-quark transitions γγ→qq. Thus we get new evidence of the four-quark nature of these states.展开更多
As in the case of the expression for enstrophy (1/2ζ~2) and equations for barotropic and baroclinic enstrophy,this paper presents an expression of divergence assumed to have its quasi energy because of flows (DQE,or ...As in the case of the expression for enstrophy (1/2ζ~2) and equations for barotropic and baroclinic enstrophy,this paper presents an expression of divergence assumed to have its quasi energy because of flows (DQE,or 1/2 D^2) with which to establish the equations of barotropie and baroclinic DQE,each consisting of five factors responsible for changes in these equations:the terms of energy flux,production,conversion,geostrophic effect and dissipation,and also a case study of a blocking event over the Sea of Okhotsk whose development is characterized largely by changes in barotropic and baroclinic DQE's on the strength of upper-level strong divergence and low-level vigorous convergence.During the event's strengthening,the baroclinic net production (inclusive of geostrophie effect) mechanism acts as the dominant factor for the enhancement of the baroclinic DQE,with its net transport outward offsetting part of its growth but the conversion mechanism augmenting its growth,and during the weakening the outward net transport of baroclinic DQE is the predominant factor of its enfeebling,baroclinic net DQE production (inclusive of geostrophic effect) and the conversion mechanisms make the baroclinic DQE increased,thereby alleviating the weakening in intensity.展开更多
Applying the wavenumber frequency transfer function to describe the whole system including tht elastic cylindrical shell and the fluid loading, a general expression of the cross spectrum of the interior noise induced ...Applying the wavenumber frequency transfer function to describe the whole system including tht elastic cylindrical shell and the fluid loading, a general expression of the cross spectrum of the interior noise induced by the TBL (turbulent boundary layer) pressure fiuctuations is derived. There are two production mechanisms of the noise: one is direct transfer of the convective ridge of the pressure fluctuations through the shell, the other is the reradiation of resonance modes excited by the pressure fluctuations. At low frequencies the noise produced by the latter mechanism is dominant. Solving the frequency equation of the cylindrical shell with liquid loading, the two Stoneley-type poles in the complex K plane are presented. They are the major sources of the reradiation of shell at low frequencies. Finally, effects of the shell radius, shell thickness, absorption of material and the flow speeds on the noise reduction are computed by numerical iniegration.展开更多
In this paper, the original process of vari-toned song in the Mmgming cicada is revealed, and the brand-new recognition for studies of the song mechanism in cicadas is opened up. Each vari-toned syllable 'Weiying&...In this paper, the original process of vari-toned song in the Mmgming cicada is revealed, and the brand-new recognition for studies of the song mechanism in cicadas is opened up. Each vari-toned syllable 'Weiying' is composed of 'Wei' with the basic sound (BS) as the dominant tone and 'ying' with the upper partials (UP2) as the dominant tone, and the upper partials (UP1) is a sound accompaniment of low intensity.The BS, UP1 and UP2 are produced by vibrations of the long ribs LR2,3 and LR1 in sounding membrane driven, separately, by two kinds of the twich in sounding muscle, 'Wei' and 'ying' are separately produced by the prin-subordinate vibrations of LR2,3 -LR1 and LR1-LR2,3. The LR1 and LR2,3 are analogous to a string tensioned two ends and a beam hinged two ends with a load in the middle respectively. Obtained the acoustic properties of sounding vibration are not only suited to the structural characteristics of LR1, 2, 3 but also consist basically with the acoustic properties of song.展开更多
文摘Cuban President Fidel Castro highly praised the products of Zhangjiakou’s Xuanhua Building Machinery Plant at a national conference in 1990. On the president’s recommendations, the Cuban ambassador to China conducted an on-the-spot investigation and expressed his appreciation of the plant’s products. Besides Cuba, the plant’s products also enjoy a high reputation among customers in Pakistan, Chile, Australia, Papua New Guinea, Ghana and Southeast Asia. Zhangjiakou had its
基金This work is supported by the Science and Technology Planning Project of Ronggui(grant number RGJF(2017)27H-8).
文摘An automated method based on the curve chain was proposed for dimensioning of engineering drawings for the mechanical products.According to the internal relation between the features of 3D model feature and elements of 2D drawing,the curve chain was established to reflect the geometric topological structure between the elements.It divides the dimensions into the absolute dimensions within the cure chain and the relative dimensions between the curve chains.The parallel and lengthy relationship between the drawing elements of the constructed X and Y parallel matrix was solved to remove redundant elements in the curve chain and labeled the absolute dimensions of the remaining valid elements.The average minimum weight coefficient was introduced to judge the dependence on the relative dimensions between curve chains.Through the analysis of the overlap between the circular rectangular areas,including all the absolute dimensions of the curve chains,overlapping curve chains were merged,and their dimensions were rearranged to avoid the cross interference between them.The method was seamlessly integrated into the drafting module of product design software NX,and it developed an automated dimensioning system.The examples show that the system has excellent interactivity and robustness in the dimensioning of product engineering drawings.The dimension information is complete,accurate and reliable.
文摘The model for forecasting the test data on mechanical products is established in the application of the grey system theories. A new formula of the background value is introduced into the model. The result of an example shows the method can reduce test expense and enhance the precision of forecasting.
文摘Since the launch of the economic reform and opening to the outside world, China has seen rapid growth in its export of mechanical and electrical products, with its export
文摘Zhejiang’s machine-building industryhas made sustained efforts to increase itsexports through the combination ofindustry and trade. In the past decade,Zhejiang’s export volume of mechanicaland electrical products has increased over 10times, becoming the leading exports fromthe province. Zhejiang has thereforebecome an important province exportingmachinery in China.
文摘The Measures for the Administration of the Import of Mechanical and Electronic' Products co-formulated by the Ministry of Commerce,the General Administration of Customs and the General Administration of Quality Supervision,Inspection and Quarantine,was hereby promul- gated,which entered into force as of May 1,2008.
文摘Factors leading to rise of prices of agricultural products mainly include tension of supply-demand relationship,promotion of production cost and circulation cost,and speculation of Refugee Capital(Hot Money).Factors leading to low price and difficult sales of agricultural products mainly include asymmetry of supply-demand information,lack of risk management tools for prices of agricultural products and decentralized and small-scaled operation of farmers.On the basis of these factors,this paper presents following countermeasures and suggestions for stabilizing prices of agricultural products:firstly,building long-effect mechanism for production and sales of agricultural products;secondly,expand the production and increase supply of agricultural products;thirdly,control the rising range of production cost for agricultural products;fourthly,enhance organization level of farmers;fifthly,promote innovation and development of risk management tools for prices of agricultural products.
基金Supported by the National Natural Science Foundation of China(U22B2075).
文摘Aiming at the four issues of underground storage state,exploitation mechanism,crude oil flow and efficient recovery,the key theoretical and technical issues and countermeasures for effective development of Gulong shale oil are put forward.Through key exploration and research on fluid occurrence,fluid phase change,exploitation mechanism,oil start-up mechanism,flow regime/pattern,exploitation mode and enhanced oil recovery(EOR)of shale reservoirs with different storage spaces,multi-scale occurrence states of shale oil and phase behavior of fluid in nano confined space were provided,the multi-phase,multi-scale flow mode and production mechanism with hydraulic fracture-shale bedding fracture-matrix infiltration as the core was clarified,and a multi-scale flow mathematical model and recoverable reserves evaluation method were preliminarily established.The feasibility of development mode with early energy replenishment and recovery factor of 3o%was discussed.Based on these,the researches of key theories and technologies for effective development of Gulong shale oil are proposed to focus on:(1)in-situ sampling and non-destructive testing of core and fluid;(2)high-temperature,high-pressure,nano-scale laboratory simulation experiment;(3)fusion of multi-scale multi-flow regime numerical simulation technology and large-scale application software;(4)waterless(CO_(2))fracturing technique and the fracturing technique for increasing the vertical fracture height;(5)early energy replenishment to enhance oil recovery;(6)lifecycle technical and economic evaluation.Moreover,a series of exploitation tests should be performed on site as soon as possible to verify the theoretical understanding,optimize the exploitation mode,form supporting technologies,and provide a generalizable development model,thereby supporting and guiding the effective development and production of Gulong shale oil.
基金This study has been supported by the Major Science and Technology Project“Comprehensive Research of Exploration Matching and Application of New Technology”(2016ZX5051-3)of CNPC.
文摘Reservoirs characterized by high temperature,high-pressure,medium high cementation strength,low porosity,and low permeability,in general,are not affected by sand production issues.Since 2009,however,it is known that cases exists where sand is present and may represent a significant technical problem(e.g.,the the Dina II condensate gas field).In the present study,the main factors affecting sand production in this type of reservoir are considered(mechanical properties,stress fields,production system,completion method and gas flow pattern changes during the production process).On this basis,a new liquid-solid coupled porous elasto-plastic 3D sand production model is introduced and validated through comparison with effective sand production data.The related prediction errors are found to be within 15%,which represents the necessary prerequisite for the utilization of such a model for the elaboration of sand prevention measures.
基金National Key R&D Program of China(2020YFD1000600)Guangdong Provincial Team of Technical System Innovation for Sugarcane Sisal Hemp Industry(2019KJ104-15)Science and Technology Planning Project of Zhanjiang City(2019A01030).
文摘[Objectives]To study the breeding of a new sugarcane variety Yuetang 08776 suitable for mechanized production.[Methods]With Yuetang 96-86 as the female parent and Yuetang 99-66 as the male parent,Yuetang 08776 was bred by the Bioengineering Institute of Guangdong Academy of Sciences.It was approved as a non-major crop variety by the Ministry of Agriculture and Rural Affairs in December,2019.Through many years of multi-pilot trials,the characters,traits and disease resistance of Yuetang 08776 were investigated,and the key points of its cultivation technique were summarized.[Results]Yuetang 08776 is characterized by medium maturity,high sugar content,high and stable yield,strong cold and drought resistance,large number of effective stems,strong ratooning ability and lodging resistance.Yuetang 08776 has excellent agronomic traits,and has been identified as moderately resistant to smut and mosaic disease.The average cane yield of Yuetang 08776 was 119.89 t/ha,18.50 t/ha higher than that of CK,an increase of 18.25%.The average sugar yield was 17.15,2.11 t/ha higher than that of CK,an increase of 14.03%.The average sucrose content of Yuetang 08776 in the early period(November to December)was 13.20%,0.71 percentage points lower than that of CK;in the middle and late period(January to March of the following year),the average sucrose content was 15.23%,0.22 percentage points lower than that of CK;and the average sucrose content of the whole period was 14.21%,0.47 percentage points lower than that of CK.[Conclusions]Yuetang 08776 is a sugarcane variety with medium maturity,high sugar,high and stable yield,strong resistance and good ratooning.It is suitable for mechanized seeding,management and harvesting,and suitable for planting and popularizing in most sugarcane production areas of Guangdong,Guangxi and Yunnan.
文摘The main technical content of full mechanized corn production in Daiyue District is explained,and the problems of disease and insect pest control in the middle and late growth stage of corn in full mechanized production are analyzed."One prevention double reduction"of corn performed by unmanned aerial vehicle(UAV)and self-propelled sprayer is compared and analyzed,and some suggestions are put forward for further popularization and application of full mechanized corn production.
基金Supported by Guangxi Scientific Research and Technology Development Program(GK AB 16380177)Project of Province and Ministry Co-sponsored Collaborative Innovation Center of Sugarcane IndustryGuangxi Special Finance Project
文摘[Objectives] This study was conducted to explore the effect of machine harvesting on ratooning ability of Guitang 47, and to provide basis for mechanized production of Guitang 47. [Methods] On the basis of mechanized planting and management of newly planted sugarcane Guitang 47, a comparative test of machine harvesting and manual harvesting was conducted, during which the plant generation rate, sugarcane yield, sucrose content and related agronomic traits of ratoon cane were continuously investigated in two years after machine harvesting of the newly planted sugarcane. [Results] There were no significant differences in the plant generation rate, plant height, stalk diameter, millable cane, sugarcane yield and sucrose content from manual harvesting of Guitang 47 in the first and second years after machine harvesting. In the second year after machine harvesting, the yields of ratoon cane and the sugar content reached 101.70 and 15.32 t/hm^2, respectively, which were equivalent to those of manual harvesting. [Conclusions] Guitang 47 has strong ratooning ability and lodging resistance and strong resistance to rolling and crushing, and is adaptive to full mechanized production. It should be promoted and accelerated in sugarcane areas lacking labor to reduce costs and increase benefits.
文摘The intrinsic product polarization and intramolecular isotope effect of the S(~1D,~3P) + HD reaction have been investigated on both the lowest singlet state(1A) and the triplet state(3A and 3A) potential energy surfaces by using quasi-classical trajectory and quantum mechanical methods.The calculations indicate that intramolecular isotope effects are different on the three electronic states.The stereodynamics study shows that the P(θr) distributions,P(φ r) distributions,and polarization-dependent differential cross sections(PDDCSs)(00) are sensitive to mass factor and the product angular momentum vectors are not only aligned but also oriented.
基金National Natural Science Foundation of China(No.81673663)CAMS Innovation Fund for Medical Sciences(CIFMS 2016-I2M-3-015)
文摘Poor bioavailability and undefined major/direct targets are two major obstacles for herbal medicines and natural products(NPs) to elucidate their precise mechanisms in vivo. Gut microbiota is an important bridge between eukayotic body and environment, which can interact with a majority of medicines with poor bioavailability and mediate their in vivo pharmacological activities. There are two main modes through which gut microbiota may mediate the pharmacological effects of NPs. First, gut microbiota catabolizes the NPs in herbal medicines into secondary metabolites with higher bioavialability and/or higher activity, facilitating the NPs enter circulation and exert beneficial impact at the pathological spot. Second, herbal medicines and NPs can favorably shift the compositional structure of gut microbiota, thereby performing remote functions to diseased organs/tissues via the systemic impaction of gut microbiota. In this review, the potential pathways were summarized through which gut microbes facilitate the pharmacological functions of herbal medicines and NPs and highlight the significance of gut microbiota in clarifying the in vivo mechanisms of herbal medicines and NPs.
基金supported by the National Major Science and Technology Program for Water Pollution Control and Treatment (Nos. 2017ZX07401003-05-01, 2014ZX07216-001)China Scholarship Council Foundation (No. 2011911098)
文摘Nitrous oxide(N2O)is one of the significant greenhouse gases,and partial nitritation-anammox(PNA)process emits higher N2O than traditional nitrogen removal processes.N2O production in PNA mainly occurs in three different pathways,i.e.,the ammonia oxidizing bacteria(AOB)denitrification,the hydroxylamine(NH2 OH)oxidation and heterotrophic denitrifiers denitrification.N2O emission data vary significantly because of the different operational conditions,bioreactor configurations,monitoring systems and quantitative methods.Under the common operational parameter scopes of PNA,N2O emission via NH2 OH oxidation dominates at relatively low dissolved oxygen(DO),low inorganic carbon(IC),high pH or low N02-concentration,while N2O emission via AOB denitrification dominates at relative higher DO,higher IC.lower pH or higher N2O-concentration.AOB are highly enriched while nitriteoxidizing bacteria(NOB)are rarely found in partial nitritation process,and the order Nitrosomonadales of AOB is the dominant group and N2O producer.Anammox bacteria,AOB and certain amount of heterotrophic denitrifying bacteria are observed in the anammox process,the genus Denitratisoma and the heterotrophic denitrifying bacteria in the deep layer of anammox granules are the dominant N2O generation bacteria.In one-stage PNA reactors,anammox bacteria account for a large fraction of the biomass,AOB account for small portion,and NOB account for even less.The microbial community,diversity and N2O producers in one-stage PNA reactors are similar with those in two-stage PNA reactors.The dominant anammox bacteria,AOB and NOB in PNA are the species Candidatus Brocadia,the genera of Nitrotoga,Nitrospira and Nitrobacter,and the genus Nitrosomonas,respectively.The relations between N2O emission pathways and microbial communities need further study in the future.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.10332040, 10502033)the Innovation Project of the Chinese Academy of Sciences (Grant No. KJCX-SW-L04).
文摘Northern pike is regarded as a specialist in swimming acceleration. The force production mechanism of northern pike, Esox lucius, during its predation S-starts was numerically studied in this article. The problem was reasonably simplified to a loose-coupling problem of fish swimming dynamics and hydrodynamics just in the swimming direction. The approach involved the simulation of the flow by solving the two-dimensional unsteady incompressible Navier-Stokes equations and decribing the fish motion dynamics based on Newton's Second Law. Visualizations of flow fields and vortex structures were performed. The results show that the large acceleration is obtained mainly in the first undulatory cycle in which the amplitude increases. In the second cycle, a couple of vortices are generated and induce a jet. In the third cycle, the jet is strengthened by the mergence of the vortices in the same direction. Through discussing the effects of various controllable factors on the swimming performance, it is found that the actual locomotion mode of the northern pike in nature is just the best choice.
基金Supported by RFFI Grant No.07-02-00093 from the Russian Foundation for Basic ResearchPresidential Grant No.NSh-1027.2008.2 for Leading Scientific Schools
文摘The surprising thing is that arising almost 50 years ago from the linear sigma model (LSM) with spontaneously broken chiral symmetry, the light scalar meson problem has become central in the nonperturbative quantum chromodynamics (QCD) for it has been made clear that LSM could be the low energy realization of QCD. First we review briefly signs of four-quark nature of light scalars. Then we show that the light scalars are produced in the two photon collisions via four-quark transitions in contrast to the classic P wave tensor qq mesons that are produced via two-quark transitions γγ→qq. Thus we get new evidence of the four-quark nature of these states.
基金supported by the National Natural Science Foundation of China(49975015)
文摘As in the case of the expression for enstrophy (1/2ζ~2) and equations for barotropic and baroclinic enstrophy,this paper presents an expression of divergence assumed to have its quasi energy because of flows (DQE,or 1/2 D^2) with which to establish the equations of barotropie and baroclinic DQE,each consisting of five factors responsible for changes in these equations:the terms of energy flux,production,conversion,geostrophic effect and dissipation,and also a case study of a blocking event over the Sea of Okhotsk whose development is characterized largely by changes in barotropic and baroclinic DQE's on the strength of upper-level strong divergence and low-level vigorous convergence.During the event's strengthening,the baroclinic net production (inclusive of geostrophie effect) mechanism acts as the dominant factor for the enhancement of the baroclinic DQE,with its net transport outward offsetting part of its growth but the conversion mechanism augmenting its growth,and during the weakening the outward net transport of baroclinic DQE is the predominant factor of its enfeebling,baroclinic net DQE production (inclusive of geostrophic effect) and the conversion mechanisms make the baroclinic DQE increased,thereby alleviating the weakening in intensity.
文摘Applying the wavenumber frequency transfer function to describe the whole system including tht elastic cylindrical shell and the fluid loading, a general expression of the cross spectrum of the interior noise induced by the TBL (turbulent boundary layer) pressure fiuctuations is derived. There are two production mechanisms of the noise: one is direct transfer of the convective ridge of the pressure fluctuations through the shell, the other is the reradiation of resonance modes excited by the pressure fluctuations. At low frequencies the noise produced by the latter mechanism is dominant. Solving the frequency equation of the cylindrical shell with liquid loading, the two Stoneley-type poles in the complex K plane are presented. They are the major sources of the reradiation of shell at low frequencies. Finally, effects of the shell radius, shell thickness, absorption of material and the flow speeds on the noise reduction are computed by numerical iniegration.
文摘In this paper, the original process of vari-toned song in the Mmgming cicada is revealed, and the brand-new recognition for studies of the song mechanism in cicadas is opened up. Each vari-toned syllable 'Weiying' is composed of 'Wei' with the basic sound (BS) as the dominant tone and 'ying' with the upper partials (UP2) as the dominant tone, and the upper partials (UP1) is a sound accompaniment of low intensity.The BS, UP1 and UP2 are produced by vibrations of the long ribs LR2,3 and LR1 in sounding membrane driven, separately, by two kinds of the twich in sounding muscle, 'Wei' and 'ying' are separately produced by the prin-subordinate vibrations of LR2,3 -LR1 and LR1-LR2,3. The LR1 and LR2,3 are analogous to a string tensioned two ends and a beam hinged two ends with a load in the middle respectively. Obtained the acoustic properties of sounding vibration are not only suited to the structural characteristics of LR1, 2, 3 but also consist basically with the acoustic properties of song.