A novel and unusual sterol with unsaturation in the△^(5(14)) position,5α-cholesta-8(14),24(25)-diene-3β,6α-diol 1,was isolated from the South China Ses sponge Dysidea sp.The structure and relative stereochemistry ...A novel and unusual sterol with unsaturation in the△^(5(14)) position,5α-cholesta-8(14),24(25)-diene-3β,6α-diol 1,was isolated from the South China Ses sponge Dysidea sp.The structure and relative stereochemistry of 1 was established by spectral analysis and comparison to the spectral data of known sterols.展开更多
Removal of uranium(VI)from nuclear wastewater is urgent due to the global nuclear energy exploitation.This study synthesized novel sponge-like 3D porous materials for enhanced uranium adsorption by combining electrosp...Removal of uranium(VI)from nuclear wastewater is urgent due to the global nuclear energy exploitation.This study synthesized novel sponge-like 3D porous materials for enhanced uranium adsorption by combining electrospinning and fibrous freeze-shaping techniques.The materials possessed an organic-inorganic hybrid architecture based on the electrospun fibers of polyacrylonitrile(PAN)and SiO_(2).As a sup-porting material,the surface of fibrous SiO_(2) could be further functionalized by cyano groups via(3-cyanopropyl)triethoxysilane.All the cyano groups were turned into amidoxime(AO)groups to obtain a amidoxime-functionalized sponge(PAO/SiO_(2)-AO)through the subsequent ami-doximation process.The proposed sponge exhibited enhanced uranium adsorption performance with a high removal capacity of 367.12 mg/g,a large adsorption coefficient of 4.0×10^(4)mL/g,and a high removal efficiency of 97.59%.The UO_(2)^(2+)adsorption kinetics perfectly conformed to the pseudo-second-order reaction.The sorbent also exhibited an excellent selectivity for UO_(2)^(2+) with other interfering metal ions.2023 Hohai University.Production and hosting by Elsevier B.V.展开更多
针对能耗等资源受限环境对密码算法的需求,基于Sponge迭代结构,采用基于新加密结构(命名为MS结构)的CLEFIA-128*(轻量级分组密码国际标准的修订算法)作为压缩函数,设计了一个轻量级Hash函数CHF。效率测试和分析表明CHF算法的软件效率高...针对能耗等资源受限环境对密码算法的需求,基于Sponge迭代结构,采用基于新加密结构(命名为MS结构)的CLEFIA-128*(轻量级分组密码国际标准的修订算法)作为压缩函数,设计了一个轻量级Hash函数CHF。效率测试和分析表明CHF算法的软件效率高于常见轻量级Hash函数,并兼顾了硬件效率,既能满足射频识别(Radio frequency identification,RFID)等资源极端受限环境对硬件的使用需求,也可以满足其他一些诸如嵌入式系统和单片机等环境对软件实现的需求,适用范围更广。依赖性测试和安全分析表明,该算法能够满足轻量级Hash函数的安全需求,也从侧面论证了MS结构的安全性。展开更多
The crystal structure of the title compound (C8H7BrN2O2, Mr=243.07) was isolated from the marine sponge Phacellia fusca Schmidt collected from the South China Sea. Its crystal structure was determined by single-crysta...The crystal structure of the title compound (C8H7BrN2O2, Mr=243.07) was isolated from the marine sponge Phacellia fusca Schmidt collected from the South China Sea. Its crystal structure was determined by single-crystal X-ray diffraction. The crystal is orthorhombic with space group Pbca, a=12.9952(8), b=7.4479(5), c=18.598(1) ?, V=1800.1(2) ?3, Z=8, Dc=1.794g/cm3, (=0.71073 ?, ( (MoK()=4.533mm-1, F(000)=960. The structrue was refined to R=0.0349, wR(F2)=0.0925 for 1589 reflections with I > 2((I). X-ray diffraction analysis reveals that the title compound has one five-membered pyrrole ring and one seven-membered azepin ring. There are two intermolecular hydrogen bonds between two molecules.展开更多
Controllable synthesis of highly active micro/nanostructured metal electrocatalysts for oxygen evolution reaction(OER) is a particularly significant and challenging target.Herein,we report a 3D porous sponge-like Ni m...Controllable synthesis of highly active micro/nanostructured metal electrocatalysts for oxygen evolution reaction(OER) is a particularly significant and challenging target.Herein,we report a 3D porous sponge-like Ni material,prepared by a facile hydrothermal method and consisting of cross-linked micro/nanofibers,as an integrated binder-free OER electrocatalyst.To further enhance the electrocatalytic performance,an N-doping strategy is applied to obtain N-doped sponge Ni(N-SN) for the first time,via NH3 annealing.Due to the combination of the unique conductive sponge structure and N doping,the as-obtainedN-SN material shows improved conductivity and a higher number of active sites,resulting in enhanced OER performance and excellent stability.Remarkably,N-SN exhibits a low overpotential of 365 mV at 100 mA cm-2 and an extremely small Tafel slope of 33 mV dec-1,as well as superior long-term stability,outperforming unmodified sponge Ni.Importantly,the combination of X-ray photoelectron spectroscopy and near-edge X-ray adsorption fine structure analyses shows that γ-NiOOH is the surface-active phase for OER.Therefore,the combination of conductive sponge structure and N-doping modification opens a new avenue for fabricating new types of high-performance electrodes with application in electrochemical energy conversion devices.展开更多
The diprotonated perchlorate salt of 2,3-di-2-pyridyl-5-nitroquinoxaline [C18H13N5O2](ClO4)2·(CH3OH)·(C2H5OH) has been synthesized and characterized by elemental analysis, IR and NMR spectra. X-ray diffracti...The diprotonated perchlorate salt of 2,3-di-2-pyridyl-5-nitroquinoxaline [C18H13N5O2](ClO4)2·(CH3OH)·(C2H5OH) has been synthesized and characterized by elemental analysis, IR and NMR spectra. X-ray diffraction analysis at room temperature indicates that the title compound (C21H23N5O12Cl2, Mr = 608.34) crystallizes in triclinic, space group P 1 with a = 7.992(8), b = 12.82(1), c = 13.42(1) A, α = 104.77(2),β = 97.84(2), r= 95.48(2)°, V= 1305(2) A3, Z = 2,DC= 1.549 g/cm3, F(000) = 628 and μ(MoKα) = 0.317 mm-1. The final R and wR factors are 0.0566 and 0.1016, respectively with 4325 independent reflections. The quinoxaline ring makes the dihedral angles of 44.2(2) and 33.9(5)° with two protonated pyridine rings whose dihedral angle is 48.1(6)°. The favored orientation of two protonated pyridine rings is that thek N atoms are opposite to each other. There exist intra- and inter-molecular N-H…O hydrogen bonds and π…π interactions which stabilize the structure further.展开更多
The crystalline sponge method is a pragmatic and promising strategy for molecular structure determination.However,the dominant metal-organic framework crystal sponge platforms always face poor chemical stability,espec...The crystalline sponge method is a pragmatic and promising strategy for molecular structure determination.However,the dominant metal-organic framework crystal sponge platforms always face poor chemical stability,especially solvent instability,hampering their application in a vaster domain.Herein,we report an ultrastable π-π stacked porous organic molecular framework which exhibits permanent porosity,high thermal stability,and good chemical resistance.It can efficiently implement an approach to molecular structure determination via a single-crystal-to-single-crystal transformation.This is the first example utilizing π-π stacked porous organic molecular framework as“crystalline sponge”to determine a wide variety of guests,ranging from hydrophilic to hydrophobic,and from aliphatic to aromatic,which complements the crystalline sponges based on the famous metal-organic frameworks.More importantly,it can achieve rapid structure determination of small molecules within 3 h.展开更多
文摘A novel and unusual sterol with unsaturation in the△^(5(14)) position,5α-cholesta-8(14),24(25)-diene-3β,6α-diol 1,was isolated from the South China Ses sponge Dysidea sp.The structure and relative stereochemistry of 1 was established by spectral analysis and comparison to the spectral data of known sterols.
基金supported by the Opening Project of the Jiangsu Province Engineering Research Center of Agricultural Breeding Pollution Control and Resource(Grant No.2021ABPCR010)the Natural Science Research Project of Jiangsu Higher Education Institutions of China(Grants No.20KJB150035,21KJD610004,and 21KJA530004).
文摘Removal of uranium(VI)from nuclear wastewater is urgent due to the global nuclear energy exploitation.This study synthesized novel sponge-like 3D porous materials for enhanced uranium adsorption by combining electrospinning and fibrous freeze-shaping techniques.The materials possessed an organic-inorganic hybrid architecture based on the electrospun fibers of polyacrylonitrile(PAN)and SiO_(2).As a sup-porting material,the surface of fibrous SiO_(2) could be further functionalized by cyano groups via(3-cyanopropyl)triethoxysilane.All the cyano groups were turned into amidoxime(AO)groups to obtain a amidoxime-functionalized sponge(PAO/SiO_(2)-AO)through the subsequent ami-doximation process.The proposed sponge exhibited enhanced uranium adsorption performance with a high removal capacity of 367.12 mg/g,a large adsorption coefficient of 4.0×10^(4)mL/g,and a high removal efficiency of 97.59%.The UO_(2)^(2+)adsorption kinetics perfectly conformed to the pseudo-second-order reaction.The sorbent also exhibited an excellent selectivity for UO_(2)^(2+) with other interfering metal ions.2023 Hohai University.Production and hosting by Elsevier B.V.
文摘针对能耗等资源受限环境对密码算法的需求,基于Sponge迭代结构,采用基于新加密结构(命名为MS结构)的CLEFIA-128*(轻量级分组密码国际标准的修订算法)作为压缩函数,设计了一个轻量级Hash函数CHF。效率测试和分析表明CHF算法的软件效率高于常见轻量级Hash函数,并兼顾了硬件效率,既能满足射频识别(Radio frequency identification,RFID)等资源极端受限环境对硬件的使用需求,也可以满足其他一些诸如嵌入式系统和单片机等环境对软件实现的需求,适用范围更广。依赖性测试和安全分析表明,该算法能够满足轻量级Hash函数的安全需求,也从侧面论证了MS结构的安全性。
文摘The crystal structure of the title compound (C8H7BrN2O2, Mr=243.07) was isolated from the marine sponge Phacellia fusca Schmidt collected from the South China Sea. Its crystal structure was determined by single-crystal X-ray diffraction. The crystal is orthorhombic with space group Pbca, a=12.9952(8), b=7.4479(5), c=18.598(1) ?, V=1800.1(2) ?3, Z=8, Dc=1.794g/cm3, (=0.71073 ?, ( (MoK()=4.533mm-1, F(000)=960. The structrue was refined to R=0.0349, wR(F2)=0.0925 for 1589 reflections with I > 2((I). X-ray diffraction analysis reveals that the title compound has one five-membered pyrrole ring and one seven-membered azepin ring. There are two intermolecular hydrogen bonds between two molecules.
基金supported by National Natural Science Foundation of China(Nos.51728204 and 51772272)Fundamental Research Funds for the Central Universities(2018QNA4011)+1 种基金Qianjiang Talents Plan D(QJD1602029)Startup Foundation for Hundred-Talent Program of Zhejiang University
文摘Controllable synthesis of highly active micro/nanostructured metal electrocatalysts for oxygen evolution reaction(OER) is a particularly significant and challenging target.Herein,we report a 3D porous sponge-like Ni material,prepared by a facile hydrothermal method and consisting of cross-linked micro/nanofibers,as an integrated binder-free OER electrocatalyst.To further enhance the electrocatalytic performance,an N-doping strategy is applied to obtain N-doped sponge Ni(N-SN) for the first time,via NH3 annealing.Due to the combination of the unique conductive sponge structure and N doping,the as-obtainedN-SN material shows improved conductivity and a higher number of active sites,resulting in enhanced OER performance and excellent stability.Remarkably,N-SN exhibits a low overpotential of 365 mV at 100 mA cm-2 and an extremely small Tafel slope of 33 mV dec-1,as well as superior long-term stability,outperforming unmodified sponge Ni.Importantly,the combination of X-ray photoelectron spectroscopy and near-edge X-ray adsorption fine structure analyses shows that γ-NiOOH is the surface-active phase for OER.Therefore,the combination of conductive sponge structure and N-doping modification opens a new avenue for fabricating new types of high-performance electrodes with application in electrochemical energy conversion devices.
基金This work was financially supported by NNSFC(No.29971019)
文摘The diprotonated perchlorate salt of 2,3-di-2-pyridyl-5-nitroquinoxaline [C18H13N5O2](ClO4)2·(CH3OH)·(C2H5OH) has been synthesized and characterized by elemental analysis, IR and NMR spectra. X-ray diffraction analysis at room temperature indicates that the title compound (C21H23N5O12Cl2, Mr = 608.34) crystallizes in triclinic, space group P 1 with a = 7.992(8), b = 12.82(1), c = 13.42(1) A, α = 104.77(2),β = 97.84(2), r= 95.48(2)°, V= 1305(2) A3, Z = 2,DC= 1.549 g/cm3, F(000) = 628 and μ(MoKα) = 0.317 mm-1. The final R and wR factors are 0.0566 and 0.1016, respectively with 4325 independent reflections. The quinoxaline ring makes the dihedral angles of 44.2(2) and 33.9(5)° with two protonated pyridine rings whose dihedral angle is 48.1(6)°. The favored orientation of two protonated pyridine rings is that thek N atoms are opposite to each other. There exist intra- and inter-molecular N-H…O hydrogen bonds and π…π interactions which stabilize the structure further.
基金supported by the National Nature Science Foundation of China(grant nos.21871266,21731006,and 21403241)the Strategic Priority Research Program of the Chinese Academy of Sciences(grant no.XDB20000000)+1 种基金Key Research Program of Frontier Science CAS(grant no.QYZDY-SSW-SLH025)Youth Innovation Promotion Association CAS.
文摘The crystalline sponge method is a pragmatic and promising strategy for molecular structure determination.However,the dominant metal-organic framework crystal sponge platforms always face poor chemical stability,especially solvent instability,hampering their application in a vaster domain.Herein,we report an ultrastable π-π stacked porous organic molecular framework which exhibits permanent porosity,high thermal stability,and good chemical resistance.It can efficiently implement an approach to molecular structure determination via a single-crystal-to-single-crystal transformation.This is the first example utilizing π-π stacked porous organic molecular framework as“crystalline sponge”to determine a wide variety of guests,ranging from hydrophilic to hydrophobic,and from aliphatic to aromatic,which complements the crystalline sponges based on the famous metal-organic frameworks.More importantly,it can achieve rapid structure determination of small molecules within 3 h.
