A series of novel hexanuclear lanthanide dusters,namely,[Ln_(6)(HL)_(6)(NO_(3))_(6)]·3CH_(3)CN(Ln=Gd(1),Tb(2),Dy(3)and Er(4))was assembled using a multidentate ligand H3L(trolamine).The clusters 1-4 show a wheel-...A series of novel hexanuclear lanthanide dusters,namely,[Ln_(6)(HL)_(6)(NO_(3))_(6)]·3CH_(3)CN(Ln=Gd(1),Tb(2),Dy(3)and Er(4))was assembled using a multidentate ligand H3L(trolamine).The clusters 1-4 show a wheel-shaped Ln_(6)topology with the approximate diameter and thickness of 1.5 and 0.7 nm,respectively.All of them show high thermal stability.In the aspect of the catalytic capacities for the cycloaddition reactions of CO_(2)and epoxide,the reaction conditions,the substrate scope,and possible catalytic mechanism were investigated.The highest yield for clusters 1-4 is up to 99%at 333 K for 12 h.In particular,cluster 1 can be reused at least three times with no obvious loss of catalytic performance and keep the integrity of the crystal structure.Magnetic investigations reveal that cluster 1 exhibits a relatively large magnetocaloric effect with-ΔS_(m)=41.43 J/(kg·K)(T=3.0 K,7.0 T);while cluster 3 displays slow magnetic relaxation behavior under zero dc field with U_(eff)=0.51 K andτ_(0)=2.54×10^(-5)s.展开更多
A 6-pyridinium salt(2)was obtalned from 2',3',5'-tri-O-acetyhnosine by use of phosphoryl chloride as the condensmg agent.The conversion of salt(2)into 6-(2- methylphenoxy)-purinenucleoside(3)denvatives und...A 6-pyridinium salt(2)was obtalned from 2',3',5'-tri-O-acetyhnosine by use of phosphoryl chloride as the condensmg agent.The conversion of salt(2)into 6-(2- methylphenoxy)-purinenucleoside(3)denvatives under mild condition is also described.展开更多
The present study involves the enantioselective resolution of racemic Felodipine by using free and immobilized forms of microbial cultures as well as an enzyme (Lipase AP6). Among the microbial cultures employed in th...The present study involves the enantioselective resolution of racemic Felodipine by using free and immobilized forms of microbial cultures as well as an enzyme (Lipase AP6). Among the microbial cultures employed in the present study, Aspergillus niger, Sphingomonas paucimobilis, Cunninghamella elegans, Escherichia coli, Pseudomonas putida and Cunninghamella blakesleeana were found to possess capability of enantioselective resolution of racemic Felodipine. The enantiomeric excess (ee%) of Felodipine after reaction catalyzed by whole-cell A. niger and S. paucimobilis was found as 81.59 and 71.67%, respectively. Immobilization enhanced the enantioselectivity (enantiomeric ratio (E)) of the biocatalysts and hence this led to enhanced enantiomeric purity of the drug. The ee% values were found to be enhanced in reactions catalyzed by A. niger and S. paucimobilis cultures after immobilization as 98.27 and 93.56%, respectively. Enantiomeric ratio (E) of the reactions catalyzed by all the biocatalysts has been improved after immobilization. E value of the reaction catalyzed by immobilized A. niger was found to be excellent (E > 100) and hence the drug showed high enantiomeric purity. In lipase AP6 catalyzed study, the enantioselectivity was enhanced after immobilization with excellent E value, which led to enhanced enantiomeric purity of the drug (99.21% ee%).展开更多
18Cr Ni Mo7-6作为海上风电机组、重型矿山装备、大型舰船、高铁等高端重载装备的主力齿轮材料,其弯曲疲劳性能是限制装备可靠性、疲劳寿命、功率密度进一步发展的重要瓶颈。然而磨削、喷丸等加工工艺对齿轮弯曲疲劳强度的具体影响尚不...18Cr Ni Mo7-6作为海上风电机组、重型矿山装备、大型舰船、高铁等高端重载装备的主力齿轮材料,其弯曲疲劳性能是限制装备可靠性、疲劳寿命、功率密度进一步发展的重要瓶颈。然而磨削、喷丸等加工工艺对齿轮弯曲疲劳强度的具体影响尚不清楚,不同可靠度的齿轮弯曲疲劳极限之间转化的问题也未见讨论,显著制约了高性能齿轮的精益设计。本文系统开展了渗碳磨削、离子注入、微粒喷丸、滚磨光整、常规喷丸、齿面+端面喷丸以及二次喷丸等系列工艺的18Cr Ni Mo7-6齿轮弯曲疲劳试验,获取有效弯曲疲劳试验点700余个,试验时长超过7000 h,并提出适用于该材料牌号的齿轮弯曲疲劳极限预测公式。结果表明,齿轮弯曲疲劳极限主要和加工工艺、模数大小、企业具体工艺环境等有关;在所研究的工艺和模数范围内,18Cr Ni Mo7-6齿轮弯曲疲劳极限范围为482~762MPa;50%可靠度与99%可靠度弯曲疲劳极限转换系数范围为0.841~0.965,推荐值为0.929;考虑表面完整性的齿轮弯曲疲劳极限预测公式的预测误差绝对值的均值为6.19%,满足工程设计需求,为高功率密度齿轮传动研发提供了研究方法与数据支撑。展开更多
为了克服人工计算方法耗时费工、计算量大、计算精度低的缺陷,实现屏蔽泵轴向力计算的快捷性和简便性,基于Visual C++ 6.0软件平台,考虑影响屏蔽泵轴向力的综合因素,编写出屏蔽泵轴向力计算程序,为屏蔽泵轴向力计算提供了便捷的工具.本...为了克服人工计算方法耗时费工、计算量大、计算精度低的缺陷,实现屏蔽泵轴向力计算的快捷性和简便性,基于Visual C++ 6.0软件平台,考虑影响屏蔽泵轴向力的综合因素,编写出屏蔽泵轴向力计算程序,为屏蔽泵轴向力计算提供了便捷的工具.本程序采用模块化的结构体系,每个模块对应界面,能灵活地实现人机对话,界面清晰,可以方便地进行参数优化设计计算.只要输入相应的设计参数,程序会自动显示出轴向力平衡的计算结果,简单快捷,与人工计算相比,大大提高了工作效率.通过真机轴向力实测与计算结果比对,计算结果与实验结果的相对误差在10%以内,证实程序计算结果具有良好的计算精度,实用性强.展开更多
合成了新化合物2,4,6-三(对甲氧基苯乙烯基)-1,3,5-均三嗪(TMST);利用红外光谱、元素分析和核磁共振(1 H NMR)分析了化合物的组成和结构,利用紫外和荧光光谱分析了其光谱特征.结果表明,在375nm的紫外光激发下,化合物在410～480nm区域发...合成了新化合物2,4,6-三(对甲氧基苯乙烯基)-1,3,5-均三嗪(TMST);利用红外光谱、元素分析和核磁共振(1 H NMR)分析了化合物的组成和结构,利用紫外和荧光光谱分析了其光谱特征.结果表明,在375nm的紫外光激发下,化合物在410～480nm区域发出较强的蓝光,对应于叶绿素a的主吸收峰;这表明其可望作为一种新的蓝光光转换剂而应用于农用薄膜.展开更多
The potent greenhouse gas SF_(6)is widely used in the field of high-voltage power insulation due to its excellent insulating properties.Currently,over 80%of the SF_(6)produced globally each year is applied in the powe...The potent greenhouse gas SF_(6)is widely used in the field of high-voltage power insulation due to its excellent insulating properties.Currently,over 80%of the SF_(6)produced globally each year is applied in the power industry,and thousands of tons of SF_(6)gas are decommissioned annually.Therefore,the treatment of SF_(6)waste gas has become an urgent issue that needs to be addressed.The harmless degradation of SF_(6)can fundamentally resolve the disposal issue of SF_(6)waste gas.This paper summarizes three primary degradation methods:thermal(catalytic)degradation,photocatalytic degradation,and plasma degradation,and reviews the research progress of emerging degradation and conversion technologies.In addition,this paper comprehensively discusses the advantages,disadvantages,and industrial application potential of various technologies from the perspectives of SF_(6)degradation efficiency and regulation of harmless product.It also analyzes the physical and chemical properties of various SF_(6)degradation products and their harmless treatment methods.A review of research shows that existing SF_(6)degradation technologies cannot meet the complex and diverse waste gas disposal needs in the power industry.There are still many challenges in balancing SF_(6)degradation indicators,differentiated response to degradation needs,recovery and economy of degradation products,treatment standards and evaluation mechanisms,and industry guidance policies.In the future,multi-means collaborative degradation methods,new reactor design and treatment process optimization,research on SF_(6)degradation reaction mechanism,and efficient catalyst design and development will serve as potential development directions.展开更多
基金the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(2021L404)。
文摘A series of novel hexanuclear lanthanide dusters,namely,[Ln_(6)(HL)_(6)(NO_(3))_(6)]·3CH_(3)CN(Ln=Gd(1),Tb(2),Dy(3)and Er(4))was assembled using a multidentate ligand H3L(trolamine).The clusters 1-4 show a wheel-shaped Ln_(6)topology with the approximate diameter and thickness of 1.5 and 0.7 nm,respectively.All of them show high thermal stability.In the aspect of the catalytic capacities for the cycloaddition reactions of CO_(2)and epoxide,the reaction conditions,the substrate scope,and possible catalytic mechanism were investigated.The highest yield for clusters 1-4 is up to 99%at 333 K for 12 h.In particular,cluster 1 can be reused at least three times with no obvious loss of catalytic performance and keep the integrity of the crystal structure.Magnetic investigations reveal that cluster 1 exhibits a relatively large magnetocaloric effect with-ΔS_(m)=41.43 J/(kg·K)(T=3.0 K,7.0 T);while cluster 3 displays slow magnetic relaxation behavior under zero dc field with U_(eff)=0.51 K andτ_(0)=2.54×10^(-5)s.
文摘A 6-pyridinium salt(2)was obtalned from 2',3',5'-tri-O-acetyhnosine by use of phosphoryl chloride as the condensmg agent.The conversion of salt(2)into 6-(2- methylphenoxy)-purinenucleoside(3)denvatives under mild condition is also described.
文摘The present study involves the enantioselective resolution of racemic Felodipine by using free and immobilized forms of microbial cultures as well as an enzyme (Lipase AP6). Among the microbial cultures employed in the present study, Aspergillus niger, Sphingomonas paucimobilis, Cunninghamella elegans, Escherichia coli, Pseudomonas putida and Cunninghamella blakesleeana were found to possess capability of enantioselective resolution of racemic Felodipine. The enantiomeric excess (ee%) of Felodipine after reaction catalyzed by whole-cell A. niger and S. paucimobilis was found as 81.59 and 71.67%, respectively. Immobilization enhanced the enantioselectivity (enantiomeric ratio (E)) of the biocatalysts and hence this led to enhanced enantiomeric purity of the drug. The ee% values were found to be enhanced in reactions catalyzed by A. niger and S. paucimobilis cultures after immobilization as 98.27 and 93.56%, respectively. Enantiomeric ratio (E) of the reactions catalyzed by all the biocatalysts has been improved after immobilization. E value of the reaction catalyzed by immobilized A. niger was found to be excellent (E > 100) and hence the drug showed high enantiomeric purity. In lipase AP6 catalyzed study, the enantioselectivity was enhanced after immobilization with excellent E value, which led to enhanced enantiomeric purity of the drug (99.21% ee%).
文摘18Cr Ni Mo7-6作为海上风电机组、重型矿山装备、大型舰船、高铁等高端重载装备的主力齿轮材料,其弯曲疲劳性能是限制装备可靠性、疲劳寿命、功率密度进一步发展的重要瓶颈。然而磨削、喷丸等加工工艺对齿轮弯曲疲劳强度的具体影响尚不清楚,不同可靠度的齿轮弯曲疲劳极限之间转化的问题也未见讨论,显著制约了高性能齿轮的精益设计。本文系统开展了渗碳磨削、离子注入、微粒喷丸、滚磨光整、常规喷丸、齿面+端面喷丸以及二次喷丸等系列工艺的18Cr Ni Mo7-6齿轮弯曲疲劳试验,获取有效弯曲疲劳试验点700余个,试验时长超过7000 h,并提出适用于该材料牌号的齿轮弯曲疲劳极限预测公式。结果表明,齿轮弯曲疲劳极限主要和加工工艺、模数大小、企业具体工艺环境等有关;在所研究的工艺和模数范围内,18Cr Ni Mo7-6齿轮弯曲疲劳极限范围为482~762MPa;50%可靠度与99%可靠度弯曲疲劳极限转换系数范围为0.841~0.965,推荐值为0.929;考虑表面完整性的齿轮弯曲疲劳极限预测公式的预测误差绝对值的均值为6.19%,满足工程设计需求,为高功率密度齿轮传动研发提供了研究方法与数据支撑。
文摘为了克服人工计算方法耗时费工、计算量大、计算精度低的缺陷,实现屏蔽泵轴向力计算的快捷性和简便性,基于Visual C++ 6.0软件平台,考虑影响屏蔽泵轴向力的综合因素,编写出屏蔽泵轴向力计算程序,为屏蔽泵轴向力计算提供了便捷的工具.本程序采用模块化的结构体系,每个模块对应界面,能灵活地实现人机对话,界面清晰,可以方便地进行参数优化设计计算.只要输入相应的设计参数,程序会自动显示出轴向力平衡的计算结果,简单快捷,与人工计算相比,大大提高了工作效率.通过真机轴向力实测与计算结果比对,计算结果与实验结果的相对误差在10%以内,证实程序计算结果具有良好的计算精度,实用性强.
文摘合成了新化合物2,4,6-三(对甲氧基苯乙烯基)-1,3,5-均三嗪(TMST);利用红外光谱、元素分析和核磁共振(1 H NMR)分析了化合物的组成和结构,利用紫外和荧光光谱分析了其光谱特征.结果表明,在375nm的紫外光激发下,化合物在410～480nm区域发出较强的蓝光,对应于叶绿素a的主吸收峰;这表明其可望作为一种新的蓝光光转换剂而应用于农用薄膜.
基金supported by National Natural Science Foundation of China Joint Fund(U24B2096)National Natural Science Foundation of China(52307170)Natural Science Foundation of Hubei Province,China(No.2023AFB382).
文摘The potent greenhouse gas SF_(6)is widely used in the field of high-voltage power insulation due to its excellent insulating properties.Currently,over 80%of the SF_(6)produced globally each year is applied in the power industry,and thousands of tons of SF_(6)gas are decommissioned annually.Therefore,the treatment of SF_(6)waste gas has become an urgent issue that needs to be addressed.The harmless degradation of SF_(6)can fundamentally resolve the disposal issue of SF_(6)waste gas.This paper summarizes three primary degradation methods:thermal(catalytic)degradation,photocatalytic degradation,and plasma degradation,and reviews the research progress of emerging degradation and conversion technologies.In addition,this paper comprehensively discusses the advantages,disadvantages,and industrial application potential of various technologies from the perspectives of SF_(6)degradation efficiency and regulation of harmless product.It also analyzes the physical and chemical properties of various SF_(6)degradation products and their harmless treatment methods.A review of research shows that existing SF_(6)degradation technologies cannot meet the complex and diverse waste gas disposal needs in the power industry.There are still many challenges in balancing SF_(6)degradation indicators,differentiated response to degradation needs,recovery and economy of degradation products,treatment standards and evaluation mechanisms,and industry guidance policies.In the future,multi-means collaborative degradation methods,new reactor design and treatment process optimization,research on SF_(6)degradation reaction mechanism,and efficient catalyst design and development will serve as potential development directions.
