Abstract The carbon-carbon bond between two nearest-neighboring atoms is mod- eled as a beam and the single-walled carbon nanotubes are treated as the space frame structures in order to analyze the mechanical properti...Abstract The carbon-carbon bond between two nearest-neighboring atoms is mod- eled as a beam and the single-walled carbon nanotubes are treated as the space frame structures in order to analyze the mechanical properties of carbon nanotubes. Based on the theory of Tersof- Brenner force feld, the energy relationships between the carbon-carbon bond and the beam model are obtained, and the stifness parameters of the beam are determined. By applying the present model, the Young’s moduli of the single-walled carbon nanotubes with diferent tube diameters are determined. And the present results are compared with available data.展开更多
Based on the Computable General Equilibrium (CGE) model and scenario analysis, the impacts of the U.S. withdrawal from the Paris Agreement on the carbon emission space and mitigation cost in China, European Union (EU)...Based on the Computable General Equilibrium (CGE) model and scenario analysis, the impacts of the U.S. withdrawal from the Paris Agreement on the carbon emission space and mitigation cost in China, European Union (EU), and Japan are assessed under Nationally Determined Contributions (NDCs) and 2 C scenarios due to the changed emission pathway of the U.S. The results show that, under the condition of constant global cumulative carbon emissions and a fixed burden-sharing scheme among countries, the failure of the U.S. to honor its NDC commitment to different degrees will increase the U.S. carbon emission space and decrease its mitigation cost. However, the carbon emission space of other parties, including China, EU, and Japan, will be reduced and their mitigation costs will be increased. In 2030, under the 2 C target, the carbon price will increase by 4.4e14.6 US$ t1 in China, by 9.7e35.4 US$ t1 in the EU, and by 16.0e53.5 US$ t1 in Japan. In addition, China, EU, and Japan will incur additional Gross Domestic Production (GDP) loss. Under the 2 C target, the GDP loss of China would increase by US$22.0e71.1 billion (equivalent to 16.4e53.1 US$ per capita), the EU's GDP loss would increase by US$9.4e32.1 billion (equivalent to 20.7e71.1 US$ per capita), and Japan's GDP loss will increase by US$4.1e13.5 billion (equivalent to 34.3e111.6 US$ per capita).展开更多
针对如何根据微纳卫星的技术状态与测控需求特点,以建立对多目标、多体制下卫星的测控管理模式的问题,从系统规划、设备研制、测控网建设等方面进行了有益的研究与分析。主要从卫星使用频率、占用轨道等空间资源的合理分配方面着手,提...针对如何根据微纳卫星的技术状态与测控需求特点,以建立对多目标、多体制下卫星的测控管理模式的问题,从系统规划、设备研制、测控网建设等方面进行了有益的研究与分析。主要从卫星使用频率、占用轨道等空间资源的合理分配方面着手,提出了适宜微纳卫星应用与发展的频率和轨道选用建议。再根据微纳卫星的技术特点,提出了采用符合CCSDS(Consultative Committee for Space Data Systems,空间数据系统咨询委员会)规程的数据格式的建议。同时,针对在轨管理,还提出了利用国内外现有有效测控资源的联网合作与商业运作的管理方式。这些观点,有可能对我国微纳卫星进行高效、可靠的测控管理提供借鉴参考。展开更多
Objective: To assess current practices, attitudes, and perceived barriers toward pediatric vision screening. Patients and Methods: A link to a 9-question survey was electronically distributed to a national sample of 6...Objective: To assess current practices, attitudes, and perceived barriers toward pediatric vision screening. Patients and Methods: A link to a 9-question survey was electronically distributed to a national sample of 6000 pediatricians through Medical Marketing Services Inc. Data were collected using Survey Monkey. Results: Email open rate was 11%;37% of those who opened the email responded (225 respondents). Over ninety percent of respondents perform some type of vision screening at least yearly, although age at which screening began varied, with two thirds of respondents instituting formal vision screening after three years. Fifty eight percent of respondents were either extremely unsatisfied, unsatisfied or only somewhat satisfied with their current screening method. Preferred methods of screening and confidence of pediatricians in their ability to detect pathology varied for children under versus over age three. The least frequently used methods for all age groups were autorefraction and photoscreening. The most commonly reported barriers to screening were inadequate training (48%), time required for exam (42%), and inadequate reimbursement (32%). Conclusions: Perceived barriers to vision screening in the pediatrician office have been previously identified, and photoscreening and autorefraction have been identified as a possible means to circumvent them. In spite of the addition of new procedural codes, pediatricians continue to report similar barriers to screening.展开更多
We introduce the concept of a weakly G-quasiconvex map with respect to a map on generalized convex spaces and use the concept to prove coincidence point theorems and almost-like coincidence point theorems. As applicat...We introduce the concept of a weakly G-quasiconvex map with respect to a map on generalized convex spaces and use the concept to prove coincidence point theorems and almost-like coincidence point theorems. As applications of the above results, we derive almost fixed point theorems and fixed point theorem. These main results generalize and improve some known results in the literature.展开更多
文摘Abstract The carbon-carbon bond between two nearest-neighboring atoms is mod- eled as a beam and the single-walled carbon nanotubes are treated as the space frame structures in order to analyze the mechanical properties of carbon nanotubes. Based on the theory of Tersof- Brenner force feld, the energy relationships between the carbon-carbon bond and the beam model are obtained, and the stifness parameters of the beam are determined. By applying the present model, the Young’s moduli of the single-walled carbon nanotubes with diferent tube diameters are determined. And the present results are compared with available data.
基金This study was supported by the 2017 National Natural Science Foundation Project “The Impacts of U.S. Withdrawal from Paris Agreement on Global Climate Governance and China's Response”.
文摘Based on the Computable General Equilibrium (CGE) model and scenario analysis, the impacts of the U.S. withdrawal from the Paris Agreement on the carbon emission space and mitigation cost in China, European Union (EU), and Japan are assessed under Nationally Determined Contributions (NDCs) and 2 C scenarios due to the changed emission pathway of the U.S. The results show that, under the condition of constant global cumulative carbon emissions and a fixed burden-sharing scheme among countries, the failure of the U.S. to honor its NDC commitment to different degrees will increase the U.S. carbon emission space and decrease its mitigation cost. However, the carbon emission space of other parties, including China, EU, and Japan, will be reduced and their mitigation costs will be increased. In 2030, under the 2 C target, the carbon price will increase by 4.4e14.6 US$ t1 in China, by 9.7e35.4 US$ t1 in the EU, and by 16.0e53.5 US$ t1 in Japan. In addition, China, EU, and Japan will incur additional Gross Domestic Production (GDP) loss. Under the 2 C target, the GDP loss of China would increase by US$22.0e71.1 billion (equivalent to 16.4e53.1 US$ per capita), the EU's GDP loss would increase by US$9.4e32.1 billion (equivalent to 20.7e71.1 US$ per capita), and Japan's GDP loss will increase by US$4.1e13.5 billion (equivalent to 34.3e111.6 US$ per capita).
文摘针对如何根据微纳卫星的技术状态与测控需求特点,以建立对多目标、多体制下卫星的测控管理模式的问题,从系统规划、设备研制、测控网建设等方面进行了有益的研究与分析。主要从卫星使用频率、占用轨道等空间资源的合理分配方面着手,提出了适宜微纳卫星应用与发展的频率和轨道选用建议。再根据微纳卫星的技术特点,提出了采用符合CCSDS(Consultative Committee for Space Data Systems,空间数据系统咨询委员会)规程的数据格式的建议。同时,针对在轨管理,还提出了利用国内外现有有效测控资源的联网合作与商业运作的管理方式。这些观点,有可能对我国微纳卫星进行高效、可靠的测控管理提供借鉴参考。
文摘Objective: To assess current practices, attitudes, and perceived barriers toward pediatric vision screening. Patients and Methods: A link to a 9-question survey was electronically distributed to a national sample of 6000 pediatricians through Medical Marketing Services Inc. Data were collected using Survey Monkey. Results: Email open rate was 11%;37% of those who opened the email responded (225 respondents). Over ninety percent of respondents perform some type of vision screening at least yearly, although age at which screening began varied, with two thirds of respondents instituting formal vision screening after three years. Fifty eight percent of respondents were either extremely unsatisfied, unsatisfied or only somewhat satisfied with their current screening method. Preferred methods of screening and confidence of pediatricians in their ability to detect pathology varied for children under versus over age three. The least frequently used methods for all age groups were autorefraction and photoscreening. The most commonly reported barriers to screening were inadequate training (48%), time required for exam (42%), and inadequate reimbursement (32%). Conclusions: Perceived barriers to vision screening in the pediatrician office have been previously identified, and photoscreening and autorefraction have been identified as a possible means to circumvent them. In spite of the addition of new procedural codes, pediatricians continue to report similar barriers to screening.
基金Supported by the Science Foundation of Education Committee of Jilin Province （20111434]）
文摘We introduce the concept of a weakly G-quasiconvex map with respect to a map on generalized convex spaces and use the concept to prove coincidence point theorems and almost-like coincidence point theorems. As applications of the above results, we derive almost fixed point theorems and fixed point theorem. These main results generalize and improve some known results in the literature.
