A new type of rice seedling carrier named seedling-growing bowl tray made of paddy straw(SGBTMPS)was developed in China.Traditional preparation process for SGBTMPS is complex and difficult to operate.Hence,a new SGBTM...A new type of rice seedling carrier named seedling-growing bowl tray made of paddy straw(SGBTMPS)was developed in China.Traditional preparation process for SGBTMPS is complex and difficult to operate.Hence,a new SGBTMPS preparation method has been developed by using straw powder as the main raw material.In this method,modified starch-based adhesive was replaced by the binder of thermosetting adhesive,and preparation constraints such as forming pressure,forming temperature,and dwell time were decreased.The effects of factors such as glue(modified starch-based adhesive),forming pressure,forming temperature and dwell time on SGBTMPS preparation were evaluated by single factor experiment.Orthogonal experiment and comprehensive weight analyses were adopted to optimize the parameters for SGBTMPS preparation.The results showed that optimized parameters were 125% glue and 1.2 kg mixed materials with the forming pressure,temperature,and dwell time of 30 MPa,140℃ and 330 seconds,respectively.Compared with traditional preparation process,the proportioning link,preparation link,and preparation time in the new preparation process were reduced by 66.7%,33.3%,and 17%,respectively;the pot-hole percentage and the expansion ratio were increased by 0.09% and 0.05%,respectively.This study indicated that the new preparation process for SGBTMPS was simpler and easier to operate and would provide a useful reference for further research and industrialization on SGBTMPS.展开更多
As open substructures of fullerenes,aromaticπ-bowls are promising candidates as new organic semiconductors,as well as attractive hosts for fullerenes.We demonstrate herein the synthesis and characterization of a nove...As open substructures of fullerenes,aromaticπ-bowls are promising candidates as new organic semiconductors,as well as attractive hosts for fullerenes.We demonstrate herein the synthesis and characterization of a novel C_(2v)symmetricπ-bowl,pyracyleno[6,5,4,3,2,1-pqrstuv]pentaphene(3).Bowl 3 was equipped with two distinctive reactive sites,allowing for bromination and cross-coupling reactions to readily yield functionalized bowls with two 2,4,6-trimethylphenyl(5)and triethylsilyl(TES)-ethynyl(6)substituents,respectively.Variable-temperature 1H NMR analysis and density functional theory(DFT)calculations indicated bowl-to-bowl inversions of 3,5,and 6 at room temperature.By alternating the substituents,the crystal structures of the threeπ-bowls 3,5,and 6 could be controlled from 1D linear to 1D slipped to 2D herringbone packing motifs,providing insight into the packing behavior ofπ-bowls.1H NMR titration study indicated that the TES-ethynyl substituent enhanced the ability ofπ-bowl to bind C_(70)with an association constant of 2485 M−1.The C_(70)molecules withπ-bowls 3 and 6 formed 1:1 complexes,in which C_(70)molecules aggregated into zig-zag and 1D linear arrays,respectively.The hole mobility of 2.3 cm^(2)V^(−1)^s(−1)and electron mobility of 0.16 cm^(2)V^(−1)^s(−1)ofπ-bowl 3 and its complex with C_(70)were demonstrated,respectively,which proved a great value for the development of aromaticπ-bowl semiconductors with tunable properties for organic electronic devices.展开更多
To improve the efficiency of fetching and transplanting seedlings for the mechanization of strawberry planting,an integrated transplanting mechanism was designed with protruding,fetching and planting performance to ac...To improve the efficiency of fetching and transplanting seedlings for the mechanization of strawberry planting,an integrated transplanting mechanism was designed with protruding,fetching and planting performance to achieve rapid fetching and pushing bowl movements.According to the working principle of the slewing mechanism,a kinematics model and the optimization goal were established,respectively.Based on visual auxiliary analysis software,optimal parameters were obtained.A three-dimensional model was established to obtain a simulation trajectory by means of a virtual simulation design analysis.Three-dimensional printing technology was used to manufacture the test prototype,and the actual working trajectories of the test prototype were extracted using high-speed photography technology,which verified the consistency of the actual trajectory with the theoretical and simulated trajectories.A prototype transplanting experiment was performed with the success rate of seedling extraction of 91.2%and excellent planting rate of 82.8%,which met the requirements for integrated strawberry harvesting,planting and transplanting.The experimental results verified the correctness and feasibility of the design of integrated transplanting mechanism.展开更多
Zhu Tong has never forgotten the mist that gushes out when the steamer opens.As the breakfast joint owncr scoops out glistening grains into a bowl,he tops it with sprinkles of fried dough and a gencrous ladle of broth...Zhu Tong has never forgotten the mist that gushes out when the steamer opens.As the breakfast joint owncr scoops out glistening grains into a bowl,he tops it with sprinkles of fried dough and a gencrous ladle of broth made with mushroom and minced pork.Zhu would use a stainless stecl spoon to thoroughly scrape down every inch of his bowl.展开更多
The conjugated polycycles show excellent optical and electrical properties that are suitable for application in various organic electronics.While most of attentions have been paid to polycycles having planar π-conjug...The conjugated polycycles show excellent optical and electrical properties that are suitable for application in various organic electronics.While most of attentions have been paid to polycycles having planar π-conjugated system,the curved polycycles seem amazing due to their unique physical and chemical features.The non-planar conjugated polycycles have been created with the geometries of bracelet,saddle,bowl,Mobius band,helicenes,etc.Among them,the bowl-shaped one is of growing interest owing to the multidiscipline applications such as synthetic intermediates for end-cap of carbon nanotube,coordination with metal ions,encapsulation of fullerenes,and fabrication of electronic devices.In this paper,we summarize the recent advances on the chemistry of the bowl-shaped conjugated polycycles,particularly on their synthesis and the further chemical modifications toward organic functional materials.展开更多
The major advantages of homogeneous charge compression ignition （HCCI） are high efficiency in combination with low NOx-emissions. However, one of the major challenges with HCCI is the control of higher peak pressure...The major advantages of homogeneous charge compression ignition （HCCI） are high efficiency in combination with low NOx-emissions. However, one of the major challenges with HCCI is the control of higher peak pressures which may damage the engine, limiting the HCCI engine life period. In this paper, an attempt is made to analyze computationally the effect of induction swirl in controlling the peak pressures of an HCCI engine under various operating parameters. A single cylinder 1.6 L reentrant piston bowl diesel engine is chosen. For computational analysis, the ECFM-3Z model of STAR - CD is considered because it is suitable for analyzing the combustion processes in SI and CI engines. As an HCCI engine is a hybrid version of SI and CI engines, the ECFM- 3Z model with necessary modifications is used to analyze the peak pressures inside the combustion chamber. The ECFM-3Z model for HCCI mode of combustion is validated with the existing literature to make sure that the results obtained are accurate. Numerical experiments are performed to study the effect of varying properties like speed of the engine, piston bowl geometry, exhaust gas recirculation （EGR） and equivalence ratio under different swirl ratios in controlling the peak pressures inside the combustion chamber. The results show that the swirl ratio has a considerable impact on controlling the peak pressures of HCCI engine. A reduction in peak pressures are observed with a swirl ratio of 4 because of reduced in cylinder temperatures. The combined effect of four operating parameters, i.e., the speed of the engine, piston bowl geometry, EGR, and equivalence ratio with swirl ratios suggest that lower intake temperatures, reentrant piston bowl, higher engine speeds and higher swirl ratios are favorable in controlling the peak pressures.展开更多
基金the projects financially supported by National Agricultural Science and Technology Achievement Transformation Project(No.2009GB2B200101)2011 Specialized Research Fund for the Doctoral Program of Higher Education(No.20112305120003)+1 种基金2009 Specialized Research Fund for the Doctoral Program of Higher Education(No.20092305110002)Start-up Capital of Doctoral Research of Heilongjiang Bayi Agricultural University(No.2011YB-08).
文摘A new type of rice seedling carrier named seedling-growing bowl tray made of paddy straw(SGBTMPS)was developed in China.Traditional preparation process for SGBTMPS is complex and difficult to operate.Hence,a new SGBTMPS preparation method has been developed by using straw powder as the main raw material.In this method,modified starch-based adhesive was replaced by the binder of thermosetting adhesive,and preparation constraints such as forming pressure,forming temperature,and dwell time were decreased.The effects of factors such as glue(modified starch-based adhesive),forming pressure,forming temperature and dwell time on SGBTMPS preparation were evaluated by single factor experiment.Orthogonal experiment and comprehensive weight analyses were adopted to optimize the parameters for SGBTMPS preparation.The results showed that optimized parameters were 125% glue and 1.2 kg mixed materials with the forming pressure,temperature,and dwell time of 30 MPa,140℃ and 330 seconds,respectively.Compared with traditional preparation process,the proportioning link,preparation link,and preparation time in the new preparation process were reduced by 66.7%,33.3%,and 17%,respectively;the pot-hole percentage and the expansion ratio were increased by 0.09% and 0.05%,respectively.This study indicated that the new preparation process for SGBTMPS was simpler and easier to operate and would provide a useful reference for further research and industrialization on SGBTMPS.
基金support of the National Natural Science Foundation of China(NSFC)(grant nos.21871022,22005018,22175013)JSPS KAKENHI(grant nos.JP20H00379(H.Y.),JP20H05833(H.Y.),and JP20H02816(H.H.)).
文摘As open substructures of fullerenes,aromaticπ-bowls are promising candidates as new organic semiconductors,as well as attractive hosts for fullerenes.We demonstrate herein the synthesis and characterization of a novel C_(2v)symmetricπ-bowl,pyracyleno[6,5,4,3,2,1-pqrstuv]pentaphene(3).Bowl 3 was equipped with two distinctive reactive sites,allowing for bromination and cross-coupling reactions to readily yield functionalized bowls with two 2,4,6-trimethylphenyl(5)and triethylsilyl(TES)-ethynyl(6)substituents,respectively.Variable-temperature 1H NMR analysis and density functional theory(DFT)calculations indicated bowl-to-bowl inversions of 3,5,and 6 at room temperature.By alternating the substituents,the crystal structures of the threeπ-bowls 3,5,and 6 could be controlled from 1D linear to 1D slipped to 2D herringbone packing motifs,providing insight into the packing behavior ofπ-bowls.1H NMR titration study indicated that the TES-ethynyl substituent enhanced the ability ofπ-bowl to bind C_(70)with an association constant of 2485 M−1.The C_(70)molecules withπ-bowls 3 and 6 formed 1:1 complexes,in which C_(70)molecules aggregated into zig-zag and 1D linear arrays,respectively.The hole mobility of 2.3 cm^(2)V^(−1)^s(−1)and electron mobility of 0.16 cm^(2)V^(−1)^s(−1)ofπ-bowl 3 and its complex with C_(70)were demonstrated,respectively,which proved a great value for the development of aromaticπ-bowl semiconductors with tunable properties for organic electronic devices.
基金Supported by the National Natural Science Foundation of China Youth Fund Project(52005221)"the 13th Five-Year"National Key Research and Development Program:High-speed Planting Technology and Equipment Research and Development(2017YFD0700800)。
文摘To improve the efficiency of fetching and transplanting seedlings for the mechanization of strawberry planting,an integrated transplanting mechanism was designed with protruding,fetching and planting performance to achieve rapid fetching and pushing bowl movements.According to the working principle of the slewing mechanism,a kinematics model and the optimization goal were established,respectively.Based on visual auxiliary analysis software,optimal parameters were obtained.A three-dimensional model was established to obtain a simulation trajectory by means of a virtual simulation design analysis.Three-dimensional printing technology was used to manufacture the test prototype,and the actual working trajectories of the test prototype were extracted using high-speed photography technology,which verified the consistency of the actual trajectory with the theoretical and simulated trajectories.A prototype transplanting experiment was performed with the success rate of seedling extraction of 91.2%and excellent planting rate of 82.8%,which met the requirements for integrated strawberry harvesting,planting and transplanting.The experimental results verified the correctness and feasibility of the design of integrated transplanting mechanism.
文摘Zhu Tong has never forgotten the mist that gushes out when the steamer opens.As the breakfast joint owncr scoops out glistening grains into a bowl,he tops it with sprinkles of fried dough and a gencrous ladle of broth made with mushroom and minced pork.Zhu would use a stainless stecl spoon to thoroughly scrape down every inch of his bowl.
基金the National Natural Science Foundation of China(Nos.21522203,21372111,and 21190034)State Key Laboratory of Applied Organic Chemistry for the financial support
文摘The conjugated polycycles show excellent optical and electrical properties that are suitable for application in various organic electronics.While most of attentions have been paid to polycycles having planar π-conjugated system,the curved polycycles seem amazing due to their unique physical and chemical features.The non-planar conjugated polycycles have been created with the geometries of bracelet,saddle,bowl,Mobius band,helicenes,etc.Among them,the bowl-shaped one is of growing interest owing to the multidiscipline applications such as synthetic intermediates for end-cap of carbon nanotube,coordination with metal ions,encapsulation of fullerenes,and fabrication of electronic devices.In this paper,we summarize the recent advances on the chemistry of the bowl-shaped conjugated polycycles,particularly on their synthesis and the further chemical modifications toward organic functional materials.
文摘The major advantages of homogeneous charge compression ignition （HCCI） are high efficiency in combination with low NOx-emissions. However, one of the major challenges with HCCI is the control of higher peak pressures which may damage the engine, limiting the HCCI engine life period. In this paper, an attempt is made to analyze computationally the effect of induction swirl in controlling the peak pressures of an HCCI engine under various operating parameters. A single cylinder 1.6 L reentrant piston bowl diesel engine is chosen. For computational analysis, the ECFM-3Z model of STAR - CD is considered because it is suitable for analyzing the combustion processes in SI and CI engines. As an HCCI engine is a hybrid version of SI and CI engines, the ECFM- 3Z model with necessary modifications is used to analyze the peak pressures inside the combustion chamber. The ECFM-3Z model for HCCI mode of combustion is validated with the existing literature to make sure that the results obtained are accurate. Numerical experiments are performed to study the effect of varying properties like speed of the engine, piston bowl geometry, exhaust gas recirculation （EGR） and equivalence ratio under different swirl ratios in controlling the peak pressures inside the combustion chamber. The results show that the swirl ratio has a considerable impact on controlling the peak pressures of HCCI engine. A reduction in peak pressures are observed with a swirl ratio of 4 because of reduced in cylinder temperatures. The combined effect of four operating parameters, i.e., the speed of the engine, piston bowl geometry, EGR, and equivalence ratio with swirl ratios suggest that lower intake temperatures, reentrant piston bowl, higher engine speeds and higher swirl ratios are favorable in controlling the peak pressures.
