Elastomer blends,among which natural rubber(NR)and butadiene rubber(BR),are involved in many components of the automotive/tire industry.A comprehensive understanding of their mechanical behavior requires,among other f...Elastomer blends,among which natural rubber(NR)and butadiene rubber(BR),are involved in many components of the automotive/tire industry.A comprehensive understanding of their mechanical behavior requires,among other features,a detailed description of the crosslink density in these mixtures.In the case of vulcanized immiscible blends,the distribution of the cross-link density within each of the NR-and BR-rich domains is key information,but difficult to determine using the conventional approaches used for one-component crosslinked elastomers.In this study,the vulcanization within NR/BR blends is investigated using a robust^(1)H double-quantum(DQ)MAS recoupling experiment,BaBa-xy16.Two kinds of cross-linked NR/BR blends were considered with two different microstructures for the BR component.The bulk organization of the resulting blends was first probed by analyzing the^(1)H spin-lattice relaxation behavior.In a second step,BaBa-xy16 was used to investigate,in a selective way,the cross-link heterogeneities within NR/BR blends.In particular,for immiscible NR/BR mixtures,the distribution of the cross-link density between both phases was compared and the observed differences were discussed.展开更多
When two representations of the Lie algebra are coupled, the coupling integral kernels are presented to relate the coupled to uncoupled group-related coherent states. These kernels have a connection with usual couplin...When two representations of the Lie algebra are coupled, the coupling integral kernels are presented to relate the coupled to uncoupled group-related coherent states. These kernels have a connection with usual coupling coefficients. The explicit expressions of these kernels for and are given. When the direct product of three representations is formed in two ways, the recoupling integral kernels relating to the coupled group-related coherent states corresponding to two different schemes are introduced, and the relations between these kernels and the general recoupling coefficients are obtained. The properties of these kernels are discussed.展开更多
As the demand for livestock products continues to increase in China,so too does the challenge of managing increasing quantities of manure.Urgent action is needed to control point source(housing,storage and processing)...As the demand for livestock products continues to increase in China,so too does the challenge of managing increasing quantities of manure.Urgent action is needed to control point source(housing,storage and processing)and diffuse(field application)pollution and improve the utilization of manure nutrients and organic matter.Here,we review strategies to improve management at each stage of the manure management chain and at different scales.Many strategies require infrastructure investment,e.g.,for containment of all manure fractions.Engineering solutions are needed to develop advanced composting systems with lower environmental footprints and design more efficient nutrient stripping technologies.At the field-scale,there is an urgent need to develop a manure nutrient recommendation system that accounts for the range of manure types,cropping systems,soils and climates throughout China.At the regional scale,coordinated planning is necessary to promote recoupling of livestock and cropping systems,and reduce nutrient accumulation in regions with little available landbank,while minimizing the risk of pollution swapping from one region to another.A range of stakeholders are needed to support the step change and innovation required to improve manure management,reduce reliance on inorganic fertilizers,and generate new business opportunities.展开更多
基金financial support from the French National Research Agency(ANR)[grant number ANR-22-CE06-0031]。
文摘Elastomer blends,among which natural rubber(NR)and butadiene rubber(BR),are involved in many components of the automotive/tire industry.A comprehensive understanding of their mechanical behavior requires,among other features,a detailed description of the crosslink density in these mixtures.In the case of vulcanized immiscible blends,the distribution of the cross-link density within each of the NR-and BR-rich domains is key information,but difficult to determine using the conventional approaches used for one-component crosslinked elastomers.In this study,the vulcanization within NR/BR blends is investigated using a robust^(1)H double-quantum(DQ)MAS recoupling experiment,BaBa-xy16.Two kinds of cross-linked NR/BR blends were considered with two different microstructures for the BR component.The bulk organization of the resulting blends was first probed by analyzing the^(1)H spin-lattice relaxation behavior.In a second step,BaBa-xy16 was used to investigate,in a selective way,the cross-link heterogeneities within NR/BR blends.In particular,for immiscible NR/BR mixtures,the distribution of the cross-link density between both phases was compared and the observed differences were discussed.
文摘When two representations of the Lie algebra are coupled, the coupling integral kernels are presented to relate the coupled to uncoupled group-related coherent states. These kernels have a connection with usual coupling coefficients. The explicit expressions of these kernels for and are given. When the direct product of three representations is formed in two ways, the recoupling integral kernels relating to the coupled group-related coherent states corresponding to two different schemes are introduced, and the relations between these kernels and the general recoupling coefficients are obtained. The properties of these kernels are discussed.
基金support from the Academy for Agricultural Green Development,the UK-China Virtual Joint Centres on Nitrogen,N-Circle and CINAgfunded by the Newton Fund via UK BBSRC/NERC(BB/N013484/1 and BB/N013468/1,respectively)+1 种基金the Chinese Ministry of Science and Technology,and the Sustainable Agriculture Innovation Network(SAIN)financial support from the National Natural Science Foundation of China(31772393)for supporting Yong Hou。
文摘As the demand for livestock products continues to increase in China,so too does the challenge of managing increasing quantities of manure.Urgent action is needed to control point source(housing,storage and processing)and diffuse(field application)pollution and improve the utilization of manure nutrients and organic matter.Here,we review strategies to improve management at each stage of the manure management chain and at different scales.Many strategies require infrastructure investment,e.g.,for containment of all manure fractions.Engineering solutions are needed to develop advanced composting systems with lower environmental footprints and design more efficient nutrient stripping technologies.At the field-scale,there is an urgent need to develop a manure nutrient recommendation system that accounts for the range of manure types,cropping systems,soils and climates throughout China.At the regional scale,coordinated planning is necessary to promote recoupling of livestock and cropping systems,and reduce nutrient accumulation in regions with little available landbank,while minimizing the risk of pollution swapping from one region to another.A range of stakeholders are needed to support the step change and innovation required to improve manure management,reduce reliance on inorganic fertilizers,and generate new business opportunities.
