The development of hydrogen-bonded organic frameworks(HOFs)faces significant constraints,primarily attributed to their fragile architectures and limited functionalization capabilities.To overcome these limitations,thi...The development of hydrogen-bonded organic frameworks(HOFs)faces significant constraints,primarily attributed to their fragile architectures and limited functionalization capabilities.To overcome these limitations,this work presents a new polymeron-HOF strategy by covalently tethering armor-like polymers onto the surface of HOFs.The application of this approach not only bolsters the stability of HOFs,but also facilitates the customization of their functional expansion in radionuclide sequestration.The optimized HOF-polymer materials display extraordinary ability in radionuclide sequestration,achieving uptake of I^(-)(0.699 g g^(-1)),IO_(3)^(-)(0.285 g g^(-1))and ReO_(4)^(-)(1.616 g g^(-1),setting a world record),fast adsorption kinetics(~100% removal within 45 s),and exceptional regeneration capability(>30 cycles)under continuous flow conditions.These outstanding performances benefit from the internal porous channels and surface imidazolium polymer coatings of HOFs,as proved by density functional theory calculation and molecular dynamics simulations.This work paves the way for the rational design of HOF-based hybrid materials tailored to versatile applications.展开更多
Although the construction of specific functional crystalline materials is still challenging,the multi-component molecular assembly has become a key solution for the design of functional materials.Here,we report a hydr...Although the construction of specific functional crystalline materials is still challenging,the multi-component molecular assembly has become a key solution for the design of functional materials.Here,we report a hydrogen-bonded organic framework(HOF)material FJU-360 constructed from disodium 6‑hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonate(SSY)and terephthalimidamide.The charge-assisted hydrogen bonding between amidinium and sulfonate makes FJU-360 produce much stronger fluorescence than SSY,and can be used as a luminescence sensor to rapidly quench aniline through luminescence quenching.FJU-360 is sensitive and highly selective for the detection of aniline,and the detection limit reached 3.2 nmol/L,which is the lowest value reported currently.The mechanism of aniline response was analyzed through the aniline@FJU-360 single crystal structure,and the luminescence mechanism was clarified through density function theory calculations.This work is an important step towards the rational synthesis and assembly of sensing materials.展开更多
A novel hydrogen-bonded organic frameworks(HOFs)FJU-200 has been constructed from N,N’-bis(5-isophthalic acid)naphthalimide(H_(4)L).FJU-200 has a good dual-function of aniline and ultraviolet detection.FJU-200 is the...A novel hydrogen-bonded organic frameworks(HOFs)FJU-200 has been constructed from N,N’-bis(5-isophthalic acid)naphthalimide(H_(4)L).FJU-200 has a good dual-function of aniline and ultraviolet detection.FJU-200 is the first case of HOF with dual sensing of visual color changes and photoluminescence quenching for aniline detection,and the detection limit of aniline can reach5.5 x 10^(-4)mol/L.Under ultraviolet FJU-200 will rapidly change from light yellow to rustic brown,which makes it possible to use FJU-200 to achieve minute-level ultraviolet detection.Moreover,for more convenient use,FJU-200 test papers are prepared.Using them,convenient and fast aniline or ultraviolet detection can be realized.The single-crystal X-ray structures show that compared with the original FJU-200,both PhNH_(2)@FJU-200 and UV-FJU-200 have larger pore sizes,and the dihedral angles of the H_(2)L^(2-)in framework has been changed.展开更多
A novel method based on interval temporal syntactic model was proposed to recognize human activities in video flow. The method is composed of two parts: feature extract and activities recognition. Trajectory shape des...A novel method based on interval temporal syntactic model was proposed to recognize human activities in video flow. The method is composed of two parts: feature extract and activities recognition. Trajectory shape descriptor, speeded up robust features(SURF) and histograms of optical flow(HOF) were proposed to represent human activities, which provide more exhaustive information to describe human activities on shape, structure and motion. In the process of recognition, a probabilistic latent semantic analysis model(PLSA) was used to recognize sample activities at the first step. Then, an interval temporal syntactic model, which combines the syntactic model with the interval algebra to model the temporal dependencies of activities explicitly, was introduced to recognize the complex activities with a time relationship. Experiments results show the effectiveness of the proposed method in comparison with other state-of-the-art methods on the public databases for the recognition of complex activities.展开更多
This paper presents a human action recognition method. It analyzes the spatio-temporal grids along the dense trajectories and generates the histogram of oriented gradients （HOG） and histogram of optical flow （HOF）...This paper presents a human action recognition method. It analyzes the spatio-temporal grids along the dense trajectories and generates the histogram of oriented gradients （HOG） and histogram of optical flow （HOF） to describe the appearance and motion of the human object. Then, HOG combined with HOF is converted to bag-of-words （BoWs） by the vocabulary tree. Finally, it applies random forest to recognize the type of human action. In the experiments, KTH database and URADL database are tested for the performance evaluation. Comparing with the other approaches, we show that our approach has a better performance for the action videos with high inter-class and low inter-class variabilities.展开更多
A kind of n-type HoF_3-doped zinc oxide-based transparent conductive film has been developed by electron beam evaporation and studied under thermal annealing in air and vacuum at temperatures 100–500℃.Effective subs...A kind of n-type HoF_3-doped zinc oxide-based transparent conductive film has been developed by electron beam evaporation and studied under thermal annealing in air and vacuum at temperatures 100–500℃.Effective substitutional dopings of F to O and Ho to Zn are realized for the films with smooth surface morphology and average grain size of about 50 nm.The hall mobility,electron concentration,resistivity and work function for the asdeposited films are 47.89 cm^2/Vs,1.39×10^(20)cm^(-3),9.37×10^(-4)Ω·cm and 5.069 eV,respectively.In addition,the average transmittance in the visible region(400–700 nm)approximates to 87%.The HoF_3:ZnO films annealed in air and vacuum can retain good optoelectronic properties under 300℃,thereinto,more stable electrical properties can be found in the air-annealed films than in the vacuum-annealed films,which is assumed to be a result of improved nano-crystalline lattice quality.The optimized films for most parameters can be obtained at 200℃ for the air-annealing case and at room temperature for the vacuum annealing case.The advisable optoelectronic properties imply that HoF_3:ZnO can facilitate carrier injection and has promising applications in energy and light sources as transparent electrodes.展开更多
The sendempirical method AM1 was used to calculate AHOF values ofperylenequinone (PQ), and HOF was used as a theoretical parameter to predict the scavengingability of Po hydroxyls. Owing to strong intramolecular hydro...The sendempirical method AM1 was used to calculate AHOF values ofperylenequinone (PQ), and HOF was used as a theoretical parameter to predict the scavengingability of Po hydroxyls. Owing to strong intramolecular hydrogen bonds and the electronattracting property of the keto-function, hydroxyls of PQ were so weak in scavenging free radicalsthat the its effect was negligible in photodynandc therapy. However, when Po was substitilted withstrong electron-donating groups, its scavenging activity was enhanced markedly.展开更多
SrS∶HoF 3 thin film was prepared by double source method with electron beam evaporation. The fine structure of electroluminescence (EL) spectrum is found for the symmetry of the SrS∶HoF 3 thin film to be lower. Th...SrS∶HoF 3 thin film was prepared by double source method with electron beam evaporation. The fine structure of electroluminescence (EL) spectrum is found for the symmetry of the SrS∶HoF 3 thin film to be lower. The broadness of red peak is wider than that of ZnS∶HoF 3 thin film. Red EL emission in the SrS∶HoF 3 thin film comes from 5F 3 5I 7+ 5F 5 5I 8 transition. The intensity of blue and red emission increases obviously in the SrS∶HoF 3 EL spectrum and white EL is obtained. The EL mechanism of the SrS∶HoF 3 thin film is dominantly the energy transfer from the crystal host to luminescent centers by 4f 95d electrons.展开更多
The SrS∶HoF 3 Electroluminescent (EL) thin films are prepared at the different substrate temperature by electron beam evaporation. The crystallinity and EL characteristics of the samples are analyzed. It is found th...The SrS∶HoF 3 Electroluminescent (EL) thin films are prepared at the different substrate temperature by electron beam evaporation. The crystallinity and EL characteristics of the samples are analyzed. It is found that the main diffraction peak is (200) at the higher substrate temperature and the main diffraction peak is (111) at the lower substrate temperature. The blue emission intensity and EL brightness of the SrS∶HoF 3 thin films increase with the increase of the substrate temperature. Annealing the samples can change the cyrstal phase and strengthen the blue emission of EL thin film.展开更多
基金supported by the National Natural Science Foundation of China(22171210,21771139,U20A20141,U23A20119)CAS Project for Young Scientists in Basic Research(YSBR-039)+1 种基金Tianjin Research Innovation Project for Postgraduate Students(2022BKY200)C?EM,School of Physical Sciences and Technology,Shanghai Tech University(#EM02161943)for the scientific and financial support of EM facilities。
文摘The development of hydrogen-bonded organic frameworks(HOFs)faces significant constraints,primarily attributed to their fragile architectures and limited functionalization capabilities.To overcome these limitations,this work presents a new polymeron-HOF strategy by covalently tethering armor-like polymers onto the surface of HOFs.The application of this approach not only bolsters the stability of HOFs,but also facilitates the customization of their functional expansion in radionuclide sequestration.The optimized HOF-polymer materials display extraordinary ability in radionuclide sequestration,achieving uptake of I^(-)(0.699 g g^(-1)),IO_(3)^(-)(0.285 g g^(-1))and ReO_(4)^(-)(1.616 g g^(-1),setting a world record),fast adsorption kinetics(~100% removal within 45 s),and exceptional regeneration capability(>30 cycles)under continuous flow conditions.These outstanding performances benefit from the internal porous channels and surface imidazolium polymer coatings of HOFs,as proved by density functional theory calculation and molecular dynamics simulations.This work paves the way for the rational design of HOF-based hybrid materials tailored to versatile applications.
基金supported by the National Natural Science Foundation of China(Nos.21673039,21573042.21805039,21975044,21971038 and 21922810)the Fujian Provincial Department of Education(No.JAT200077).
文摘Although the construction of specific functional crystalline materials is still challenging,the multi-component molecular assembly has become a key solution for the design of functional materials.Here,we report a hydrogen-bonded organic framework(HOF)material FJU-360 constructed from disodium 6‑hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonate(SSY)and terephthalimidamide.The charge-assisted hydrogen bonding between amidinium and sulfonate makes FJU-360 produce much stronger fluorescence than SSY,and can be used as a luminescence sensor to rapidly quench aniline through luminescence quenching.FJU-360 is sensitive and highly selective for the detection of aniline,and the detection limit reached 3.2 nmol/L,which is the lowest value reported currently.The mechanism of aniline response was analyzed through the aniline@FJU-360 single crystal structure,and the luminescence mechanism was clarified through density function theory calculations.This work is an important step towards the rational synthesis and assembly of sensing materials.
基金supported by the National Natural Science Foundation of China(Nos.21673039,21573042,21805039,21975044,21971038 and 21922810)the Fujian Provincial Department of Science and Technology(Nos.2018J07001 and2019H6012)。
文摘A novel hydrogen-bonded organic frameworks(HOFs)FJU-200 has been constructed from N,N’-bis(5-isophthalic acid)naphthalimide(H_(4)L).FJU-200 has a good dual-function of aniline and ultraviolet detection.FJU-200 is the first case of HOF with dual sensing of visual color changes and photoluminescence quenching for aniline detection,and the detection limit of aniline can reach5.5 x 10^(-4)mol/L.Under ultraviolet FJU-200 will rapidly change from light yellow to rustic brown,which makes it possible to use FJU-200 to achieve minute-level ultraviolet detection.Moreover,for more convenient use,FJU-200 test papers are prepared.Using them,convenient and fast aniline or ultraviolet detection can be realized.The single-crystal X-ray structures show that compared with the original FJU-200,both PhNH_(2)@FJU-200 and UV-FJU-200 have larger pore sizes,and the dihedral angles of the H_(2)L^(2-)in framework has been changed.
基金Project(50808025)supported by the National Natural Science Foundation of ChinaProject(20090162110057)supported by the Doctoral Fund of Ministry of Education,China
文摘A novel method based on interval temporal syntactic model was proposed to recognize human activities in video flow. The method is composed of two parts: feature extract and activities recognition. Trajectory shape descriptor, speeded up robust features(SURF) and histograms of optical flow(HOF) were proposed to represent human activities, which provide more exhaustive information to describe human activities on shape, structure and motion. In the process of recognition, a probabilistic latent semantic analysis model(PLSA) was used to recognize sample activities at the first step. Then, an interval temporal syntactic model, which combines the syntactic model with the interval algebra to model the temporal dependencies of activities explicitly, was introduced to recognize the complex activities with a time relationship. Experiments results show the effectiveness of the proposed method in comparison with other state-of-the-art methods on the public databases for the recognition of complex activities.
基金supported by the MOST,Taiwan under Grant No.102-2221-E-468-013
文摘This paper presents a human action recognition method. It analyzes the spatio-temporal grids along the dense trajectories and generates the histogram of oriented gradients （HOG） and histogram of optical flow （HOF） to describe the appearance and motion of the human object. Then, HOG combined with HOF is converted to bag-of-words （BoWs） by the vocabulary tree. Finally, it applies random forest to recognize the type of human action. In the experiments, KTH database and URADL database are tested for the performance evaluation. Comparing with the other approaches, we show that our approach has a better performance for the action videos with high inter-class and low inter-class variabilities.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61774154 and 51503196
文摘A kind of n-type HoF_3-doped zinc oxide-based transparent conductive film has been developed by electron beam evaporation and studied under thermal annealing in air and vacuum at temperatures 100–500℃.Effective substitutional dopings of F to O and Ho to Zn are realized for the films with smooth surface morphology and average grain size of about 50 nm.The hall mobility,electron concentration,resistivity and work function for the asdeposited films are 47.89 cm^2/Vs,1.39×10^(20)cm^(-3),9.37×10^(-4)Ω·cm and 5.069 eV,respectively.In addition,the average transmittance in the visible region(400–700 nm)approximates to 87%.The HoF_3:ZnO films annealed in air and vacuum can retain good optoelectronic properties under 300℃,thereinto,more stable electrical properties can be found in the air-annealed films than in the vacuum-annealed films,which is assumed to be a result of improved nano-crystalline lattice quality.The optimized films for most parameters can be obtained at 200℃ for the air-annealing case and at room temperature for the vacuum annealing case.The advisable optoelectronic properties imply that HoF_3:ZnO can facilitate carrier injection and has promising applications in energy and light sources as transparent electrodes.
文摘The sendempirical method AM1 was used to calculate AHOF values ofperylenequinone (PQ), and HOF was used as a theoretical parameter to predict the scavengingability of Po hydroxyls. Owing to strong intramolecular hydrogen bonds and the electronattracting property of the keto-function, hydroxyls of PQ were so weak in scavenging free radicalsthat the its effect was negligible in photodynandc therapy. However, when Po was substitilted withstrong electron-donating groups, its scavenging activity was enhanced markedly.
文摘SrS∶HoF 3 thin film was prepared by double source method with electron beam evaporation. The fine structure of electroluminescence (EL) spectrum is found for the symmetry of the SrS∶HoF 3 thin film to be lower. The broadness of red peak is wider than that of ZnS∶HoF 3 thin film. Red EL emission in the SrS∶HoF 3 thin film comes from 5F 3 5I 7+ 5F 5 5I 8 transition. The intensity of blue and red emission increases obviously in the SrS∶HoF 3 EL spectrum and white EL is obtained. The EL mechanism of the SrS∶HoF 3 thin film is dominantly the energy transfer from the crystal host to luminescent centers by 4f 95d electrons.
文摘The SrS∶HoF 3 Electroluminescent (EL) thin films are prepared at the different substrate temperature by electron beam evaporation. The crystallinity and EL characteristics of the samples are analyzed. It is found that the main diffraction peak is (200) at the higher substrate temperature and the main diffraction peak is (111) at the lower substrate temperature. The blue emission intensity and EL brightness of the SrS∶HoF 3 thin films increase with the increase of the substrate temperature. Annealing the samples can change the cyrstal phase and strengthen the blue emission of EL thin film.
