Rice(Oryza sativa L.)is essential for global food security,but faces increasing threats from extreme weather.High temperatures during the grain-filling stage lower rice yields and quality(Wada et al.,2019).Studies hav...Rice(Oryza sativa L.)is essential for global food security,but faces increasing threats from extreme weather.High temperatures during the grain-filling stage lower rice yields and quality(Wada et al.,2019).Studies have revealed the mechanisms by which heat stress impairs rice quality during the grain-filling stage,including the involvement of factors such as DG1(Qin et al.,2021b),Oscp Hsp70-2(Tabassum et al.,2020),and Osb ZIP58Β(Xu et al.,2020).展开更多
绝对信号偏差(observable-specific signal bias,OSB)作为一种新的码偏差类型,对提高北斗卫星导航系统(BeiDou Navigation Satellite System,BDS)的定位精度具有重要意义.本文基于多模GNSS实验(Multi-GNSS Experiment,MGEX)测站北斗三号...绝对信号偏差(observable-specific signal bias,OSB)作为一种新的码偏差类型,对提高北斗卫星导航系统(BeiDou Navigation Satellite System,BDS)的定位精度具有重要意义.本文基于多模GNSS实验(Multi-GNSS Experiment,MGEX)测站北斗三号(BeiDou-3 Navigation Satellite System,BDS-3)新频点组合B1C/B2a,对中国科学院(Chinese Academy of Sciences,CAS)、武汉大学(Wuhan University,WHU)发布的OSB产品的稳定性和定位性能进行分析.研究发现,CAS的OSB产品稳定性普遍优于WHU产品,并会对定位性能产生影响.使用CAS产品的精密单点定位(precise point positioning, PPP)实验,其伪距、载波残差均优于WHU产品,并且其定位精度也略优于WHU产品.并且使用OSB产品可以提升PPP收敛时间,能够更快速得到较高的定位精度,而且分析了OSB产品波动对定位性能的影响,发现CAS产品波动期间,其伪距、载波残差和定位性能均有下降.展开更多
Despite its considerable potential,oil palm trunk(OPT)remains underutilized,largely owing to the cyclical replanting process that occurs every 25–30 years.This study aimed to address this issue by developing an ecofr...Despite its considerable potential,oil palm trunk(OPT)remains underutilized,largely owing to the cyclical replanting process that occurs every 25–30 years.This study aimed to address this issue by developing an ecofriendly oriented strand board(OSB)using vascular bundles(VBs)from oil palm,both in binderless form and with the incorporation of natural adhesives made from sucrose and ammonium dihydrogen phosphate(ADP).The VB was extracted from OPT using a pressure cooker and mixed with a sucrose-ADP solution at various ratios.The mixture was then pressed at temperatures of 180℃ and 200℃ for 10 min to form boards,which were evaluated based on the Japanese Industrial Standard(JIS)A 5908 for particleboards.Binderless OSB was also manufactured without the use of any adhesive components.Fourier-transform infrared(FTIR)spectroscopy was conducted to evaluate the VB and its board.The results indicated that the mechanical properties of the binderless OSB met the JIS A 5908 Type 8 requirements.Furthermore,the addition of sucrose-ADP improved the physical and mechanical properties of the board,with an optimal sucrose-to-ADP ratio of 85:15.The OSB with the best properties met the JIS A 5908 Type 13 requirements.The FTIR results indicated that carbonyl groups,furan rings,and lignin played important roles in the bonding properties of the OSB.In conclusion,this research demonstrated the potential of VBs as a raw material for producing environmentally friendly OSB,both in binderless form and with the use of sucrose-ADP.展开更多
Over the last decade,the oriented strand board(OSB)market presented meaningful growth.However,as a woodbased product,because of its anatomical structure and chemical composition,OSB can be damaged by biodeterioration ...Over the last decade,the oriented strand board(OSB)market presented meaningful growth.However,as a woodbased product,because of its anatomical structure and chemical composition,OSB can be damaged by biodeterioration agents.Given that,the biodeterioration of OSB panels must be investigated to improve its durability.In this way,this work analyses the biological resistance against termites(Cryptotermes brevis and Nasutitermes corniger)of heat-treated OSB panels made with Eucalyptus wood glued with vegetable-based polyurethane-an ecofriendly and sustainable adhesive derived from castor oil.Various panels were produced with different layers compositions(face:core:face of 25:50:25 and 30:40:30)in wood mass proportion and were submitted to postproduction heat treatment(at 175℃ and 200℃)replacing the use of chemical insecticides.The influence of the layers variation and heat treatment temperature were evaluated,and these results were compared with commercial panels(made from pinus wood with insecticide).The results showed that the heat treatment did not improve the resistance against termite attack.However,all the experimental panels presented a satisfactory performance that was compatible with the commercial panels produced with insecticide available in the Brazilian market.The combination of Eucalyptus wood and castor oil adhesive to produce OSB,in any variation of layer composition,demonstrated natural resistance against termite attack compatible with the commercial panels,even without using chemical additives to increase durability.展开更多
基金supported by the National Natural Science Foundation of China(32270250 and 32400202)National Science Foundation of Fujian Province of China(2022J02004)+1 种基金Fujian Provincial Science and Technology Key Project(2024NZ029027)China Postdoctoral Science Foundation(2022M712665)。
文摘Rice(Oryza sativa L.)is essential for global food security,but faces increasing threats from extreme weather.High temperatures during the grain-filling stage lower rice yields and quality(Wada et al.,2019).Studies have revealed the mechanisms by which heat stress impairs rice quality during the grain-filling stage,including the involvement of factors such as DG1(Qin et al.,2021b),Oscp Hsp70-2(Tabassum et al.,2020),and Osb ZIP58Β(Xu et al.,2020).
文摘为了研究使用矩形钢管连接的新型全预制冷弯薄壁型钢复合墙体的抗侧性能,设计了6个足尺试件,并进行了水平低周往复加载试验,分析了龙骨间距、覆面板类型、单面或双面覆板等因素对新型复合墙体试件抗侧性能的影响.新型墙体的覆面板为OSB板与硅晶钙板.试验结果表明:使用矩形钢管连接的新型复合墙体具有良好的整体抗震性能;单面或双面覆板对墙体抗侧性能影响显著,双面覆板的新型复合墙体的屈服荷载约为单面覆板新型复合墙体的2倍;龙骨间距和覆面板材料对墙体抗侧性能的影响相对较小.在试验基础上,使用OpenSEES软件建立了试验墙体的有限元分析模型,并针对矩形钢管壁厚、周边螺钉间距取值进行了参数分析.参数分析结果表明,矩形钢管连接件壁厚取值推荐为2.5 mm,周边螺钉间距推荐取50~100 mm.
文摘绝对信号偏差(observable-specific signal bias,OSB)作为一种新的码偏差类型,对提高北斗卫星导航系统(BeiDou Navigation Satellite System,BDS)的定位精度具有重要意义.本文基于多模GNSS实验(Multi-GNSS Experiment,MGEX)测站北斗三号(BeiDou-3 Navigation Satellite System,BDS-3)新频点组合B1C/B2a,对中国科学院(Chinese Academy of Sciences,CAS)、武汉大学(Wuhan University,WHU)发布的OSB产品的稳定性和定位性能进行分析.研究发现,CAS的OSB产品稳定性普遍优于WHU产品,并会对定位性能产生影响.使用CAS产品的精密单点定位(precise point positioning, PPP)实验,其伪距、载波残差均优于WHU产品,并且其定位精度也略优于WHU产品.并且使用OSB产品可以提升PPP收敛时间,能够更快速得到较高的定位精度,而且分析了OSB产品波动对定位性能的影响,发现CAS产品波动期间,其伪距、载波残差和定位性能均有下降.
基金The authors are grateful to the Directorate General of Higher Education,Research,and Technology of Ministry of Education,Culture,Research,and Technology of the Republic of Indonesia and Universitas Gadjah Mada(Indonesian Collaborative Research Project-World Class University Program:No.1566/UN1/DITLIT/Dit-Lit/PT.01.03/2022).
文摘Despite its considerable potential,oil palm trunk(OPT)remains underutilized,largely owing to the cyclical replanting process that occurs every 25–30 years.This study aimed to address this issue by developing an ecofriendly oriented strand board(OSB)using vascular bundles(VBs)from oil palm,both in binderless form and with the incorporation of natural adhesives made from sucrose and ammonium dihydrogen phosphate(ADP).The VB was extracted from OPT using a pressure cooker and mixed with a sucrose-ADP solution at various ratios.The mixture was then pressed at temperatures of 180℃ and 200℃ for 10 min to form boards,which were evaluated based on the Japanese Industrial Standard(JIS)A 5908 for particleboards.Binderless OSB was also manufactured without the use of any adhesive components.Fourier-transform infrared(FTIR)spectroscopy was conducted to evaluate the VB and its board.The results indicated that the mechanical properties of the binderless OSB met the JIS A 5908 Type 8 requirements.Furthermore,the addition of sucrose-ADP improved the physical and mechanical properties of the board,with an optimal sucrose-to-ADP ratio of 85:15.The OSB with the best properties met the JIS A 5908 Type 13 requirements.The FTIR results indicated that carbonyl groups,furan rings,and lignin played important roles in the bonding properties of the OSB.In conclusion,this research demonstrated the potential of VBs as a raw material for producing environmentally friendly OSB,both in binderless form and with the use of sucrose-ADP.
基金financed by Coordination for the Improvement of Higher Education Personnel,Brazil(CAPES,https://www.gov.br/capes/pt-br)(accessed on 22 September 2024)Finance Code 001(ESS,FDM)+1 种基金Sao Paulo State Research Support Foundation(FAPESP,https://fapesp.br/)(accessed on 22 September 2024)(CIC,grant number 2015/04660-0)National Council for Scientific and Technological Development(CNPq,https://www.gov.br/cnpq/pt-br)(accessed on 22 September 2024)(grant numbers 308937/2021-0(CIC),306576/2020-1(ECB),and 303099/2022-4(JBP)).
文摘Over the last decade,the oriented strand board(OSB)market presented meaningful growth.However,as a woodbased product,because of its anatomical structure and chemical composition,OSB can be damaged by biodeterioration agents.Given that,the biodeterioration of OSB panels must be investigated to improve its durability.In this way,this work analyses the biological resistance against termites(Cryptotermes brevis and Nasutitermes corniger)of heat-treated OSB panels made with Eucalyptus wood glued with vegetable-based polyurethane-an ecofriendly and sustainable adhesive derived from castor oil.Various panels were produced with different layers compositions(face:core:face of 25:50:25 and 30:40:30)in wood mass proportion and were submitted to postproduction heat treatment(at 175℃ and 200℃)replacing the use of chemical insecticides.The influence of the layers variation and heat treatment temperature were evaluated,and these results were compared with commercial panels(made from pinus wood with insecticide).The results showed that the heat treatment did not improve the resistance against termite attack.However,all the experimental panels presented a satisfactory performance that was compatible with the commercial panels produced with insecticide available in the Brazilian market.The combination of Eucalyptus wood and castor oil adhesive to produce OSB,in any variation of layer composition,demonstrated natural resistance against termite attack compatible with the commercial panels,even without using chemical additives to increase durability.
