We investigated the impure phase problem and summarized its two formation mechanisms of YAG powders synthesized via the co-precipitation method.The ions loss problem caused by high concentration reaction solution in t...We investigated the impure phase problem and summarized its two formation mechanisms of YAG powders synthesized via the co-precipitation method.The ions loss problem caused by high concentration reaction solution in the titration process was emphatically studied,and the corresponding thermodynamic explanation was carried out.In addition,influence of powder crystallinity and its new qualitative and quantitative standards were studied.One reason of impure phase is the local nonuniform mixture of Y and Al elements in precursor,which easily causes intermediate phases during calcination and difficulty of high pure powders at low temperatures.The other reason is the precipitation dissolution during titration and then the Y^(3+)/Al^(3+) loss,caused by high concentration of reaction solution.The powder crystallinity can be promoted by increasing calcination temperature or holding time of precursor.Besides the routine XRD method,the TEM-EDX method should be also introduced to directly determine the quality of crystallinity.展开更多
Yb：YAG nanopowders were synthesized by the alcohol-water co-precipitatlon method adding MgO as sintering additives. Appropriate amount of MgO adding can restrict the agglomeration and reduce the particle size of Yb：...Yb：YAG nanopowders were synthesized by the alcohol-water co-precipitatlon method adding MgO as sintering additives. Appropriate amount of MgO adding can restrict the agglomeration and reduce the particle size of Yb：YAG powders. When the MgO content was 0.04wt%, well-dispersed Yb：YAG powders with ellipsoidal particles of less than 100 nm diameter were obtained. The experimental results showed the valence variation of doping ion Yb〉 would not appear when adding MgO as sintering additives, so ceramics showed colorless transparent instead of green due to Yb^2＋ color center using traditional SiO2 as additives. The transmission of the sintered Yb：YAG ceramics can reach 80.6% even without annealing. Ceramic morphology showed that the grains had uniform-distribution with the size of 10 iam or so, and no impurity and pore existed in the grain boundary and crystalline while using optimal sintering conditions.展开更多
Breeding sterile lines is the key to the development of hybrid rice with wide adaptability. However, at present, few wide-adaptability sterile lines have been applied in production practice. In this study, Yungu 3A, a...Breeding sterile lines is the key to the development of hybrid rice with wide adaptability. However, at present, few wide-adaptability sterile lines have been applied in production practice. In this study, Yungu 3A, a new WA-type Indica CMS line with good grain quality, was developed by hybridization between Yunfeng 66A with wide adaptability as female parent and F1 plants of Yunfeng 66B/D62B as male parent and continuous backcrossing. According to the results, the finally obtained lndica CMS line Yungu 3A has good plant type and leaf shape, strong tillering ability, excellent flowering habit, stable and complete male sterility with the sterile plant rate and pollen sterility rate of 100%, strong combining ability, high outcrossing rate, low sensitivity to light and temperature, and strong disease resistance, which was approved by Yunnan Provincial Crop Variety Appraisal Committee in 2013. Yungu 3A is conducive to the development of new hybrid rice combinations with good quality and wide adaptability, exhibiting a promising prospect of application.展开更多
In this study,records published by General Administration of Quality Supervision,Inspection and Quarantine of China and related literature on harmful organisms intercepted from imported seeds and seedlings during 2011...In this study,records published by General Administration of Quality Supervision,Inspection and Quarantine of China and related literature on harmful organisms intercepted from imported seeds and seedlings during 2011-2014 were investigated and analyzed.The results showed that the species and amount of harmful organisms intercepted from imported seeds and seedlings increased gradually during 2011-2014,which posed a realistic or potential threat to agriculture production in China.Based on the present situation,corresponding suggestions and countermeasures were proposed：1 strengthening the study on rapid detection technology of harmful organisms;2 improving the ability of animal and plant quarantine in China.展开更多
基金Funded by the Science Fund of Educational Department of Henan Province of China (No. 19A430002)。
文摘We investigated the impure phase problem and summarized its two formation mechanisms of YAG powders synthesized via the co-precipitation method.The ions loss problem caused by high concentration reaction solution in the titration process was emphatically studied,and the corresponding thermodynamic explanation was carried out.In addition,influence of powder crystallinity and its new qualitative and quantitative standards were studied.One reason of impure phase is the local nonuniform mixture of Y and Al elements in precursor,which easily causes intermediate phases during calcination and difficulty of high pure powders at low temperatures.The other reason is the precipitation dissolution during titration and then the Y^(3+)/Al^(3+) loss,caused by high concentration of reaction solution.The powder crystallinity can be promoted by increasing calcination temperature or holding time of precursor.Besides the routine XRD method,the TEM-EDX method should be also introduced to directly determine the quality of crystallinity.
基金Funded by the National Natural Science Foundation of China(Nos.50872083,51002098and11145006)the Doctoral Program of Higher Education(No.20090181120092)the National High Technology Research and Development Program(863)(JG2011094)
文摘Yb：YAG nanopowders were synthesized by the alcohol-water co-precipitatlon method adding MgO as sintering additives. Appropriate amount of MgO adding can restrict the agglomeration and reduce the particle size of Yb：YAG powders. When the MgO content was 0.04wt%, well-dispersed Yb：YAG powders with ellipsoidal particles of less than 100 nm diameter were obtained. The experimental results showed the valence variation of doping ion Yb〉 would not appear when adding MgO as sintering additives, so ceramics showed colorless transparent instead of green due to Yb^2＋ color center using traditional SiO2 as additives. The transmission of the sintered Yb：YAG ceramics can reach 80.6% even without annealing. Ceramic morphology showed that the grains had uniform-distribution with the size of 10 iam or so, and no impurity and pore existed in the grain boundary and crystalline while using optimal sintering conditions.
基金Supported by Project for Introduction and Training of High-Level Technological Talents of Yunnan Province(2009CI126)New Product Program of Yunnan Province(2011BB002)Project for Construction of Science and Technology Innovation Platform of Yunnan Province(2013DH006)
文摘Breeding sterile lines is the key to the development of hybrid rice with wide adaptability. However, at present, few wide-adaptability sterile lines have been applied in production practice. In this study, Yungu 3A, a new WA-type Indica CMS line with good grain quality, was developed by hybridization between Yunfeng 66A with wide adaptability as female parent and F1 plants of Yunfeng 66B/D62B as male parent and continuous backcrossing. According to the results, the finally obtained lndica CMS line Yungu 3A has good plant type and leaf shape, strong tillering ability, excellent flowering habit, stable and complete male sterility with the sterile plant rate and pollen sterility rate of 100%, strong combining ability, high outcrossing rate, low sensitivity to light and temperature, and strong disease resistance, which was approved by Yunnan Provincial Crop Variety Appraisal Committee in 2013. Yungu 3A is conducive to the development of new hybrid rice combinations with good quality and wide adaptability, exhibiting a promising prospect of application.
基金Supported by Plan for the Construction of Technological Innovation Platform of Yunnan Province(2013DH006)Key Project of New Product Development in Yunnan Province(Agriculture)(2013BB004)Science and Technology Cooperation Project between Yunnan Province and University(2014IB012)
文摘In this study,records published by General Administration of Quality Supervision,Inspection and Quarantine of China and related literature on harmful organisms intercepted from imported seeds and seedlings during 2011-2014 were investigated and analyzed.The results showed that the species and amount of harmful organisms intercepted from imported seeds and seedlings increased gradually during 2011-2014,which posed a realistic or potential threat to agriculture production in China.Based on the present situation,corresponding suggestions and countermeasures were proposed：1 strengthening the study on rapid detection technology of harmful organisms;2 improving the ability of animal and plant quarantine in China.
