A{(3,4),4}-fullerene graph S is a 4-regular map on the sphere whose faces are of length 3 or 4.It follows from Euler s formula that the number of triangular faces is eight.A set H of disjoint quadrangular faces of S i...A{(3,4),4}-fullerene graph S is a 4-regular map on the sphere whose faces are of length 3 or 4.It follows from Euler s formula that the number of triangular faces is eight.A set H of disjoint quadrangular faces of S is called resonant pattern if S has a perfect matching M such that every quadrangular face in H is M-alternating.Let k be a positive integer,S is k-resonant if any i≤k disjoint quadrangular faces of S form a resonant pattern.Moreover,if graph S is k-resonant for any integer k,then S is called maximally resonant.In this paper,we show that the maximally resonant{(3,4),4}-fullerene graphs are S_6,S_8,S_(10)^(2),S_(12)^(2),S_(12)^(4),S_(12)^(5),S_(14)^(3),S_(14)^(5),S_(16)^(3),S_(18)^(5),S_(24)as shown in Fig.1.As a corollary,it is shown that if a{(3,4),4}-fullerene graph is 4-resonant,then it is also maximally resonant.展开更多
Based upon the new designed helical resonator,the resonant radio frequency(RF)for trapping ions can be consec-utively adjusted in a large range(about 12 MHz to 29 MHz)with high Q-factors(above 300).We analyze the heli...Based upon the new designed helical resonator,the resonant radio frequency(RF)for trapping ions can be consec-utively adjusted in a large range(about 12 MHz to 29 MHz)with high Q-factors(above 300).We analyze the helical resonator with a lumped element circuit model and find that the theoretical results fit well with the experimental data.With our resonator system,the resonant frequency near magic RF frequency(where the scalar Stark shift and the second-order Doppler shift due to excess micromotion cancel each other)can be continuously changed at kHz level.For ^(88)Sr^(+) ion,compared to earlier results,the measurement accuracy of magic RF frequency can be improved by an order of magnitude upon rough calculation,and therefore the net micromotion frequency shifts can be further reduced.Also,the differential static scalar polarizability △α0 of clock transition can be experimentally measured more accurately.展开更多
The hole-making process in stack materials consisting of carbon fiber reinforced plastics （CFRP） and Ti- 6Al-4V remains a critical challenge. In this paper, an experimental study on the helical milling of CFRP/Ti-6A...The hole-making process in stack materials consisting of carbon fiber reinforced plastics （CFRP） and Ti- 6Al-4V remains a critical challenge. In this paper, an experimental study on the helical milling of CFRP/Ti-6Al-4V stacks was conducted by using two different machining strategies. Helical milling strategy Ⅰ machines both materials with identical machining parameters, while machining strategy Ⅱ uses two sets of machining parameters to machine each material. Helical milling performance was evaluated by the following indicators： tool life, cutting forces, hole quality （including diameter deviation, roundness, roughness, and hole edge quality）. The results demonstrate that heli- cal milling strategy 11 outperformed strategy I, leading to longer tool life （up to 48 holes）, smaller cutting forces and better hole quality with higher geometric accuracy and smoother surface finish （Ra≤0.58 μm for Ti-6Al-4V and Ra ≤ 0.81 μm for CFRP）, eliminating the need for reaming or de-burring.展开更多
Objective:To evaluate the radiological features of IgG4-related disease(IgG4-RD)in the head and neck region.Methods:In this radiology-based study,radiological features,clinical,laboratory,pathological findings,and pro...Objective:To evaluate the radiological features of IgG4-related disease(IgG4-RD)in the head and neck region.Methods:In this radiology-based study,radiological features,clinical,laboratory,pathological findings,and prognosis of nine patients with head and neck involvement diagnosed with IgG4-RD were investigated retrospectively.Results:The median age of the patients was 38 years(range:2.5-79 years),and there were six males and three females.The most common symptoms and clinical findings of the patients were eyelid and lacrimal gland swelling,painless exophthalmos,and ophthalmoplegia.The most common site of involvement on MRI was the orbit.Orbital involvement was followed by branches of the trigeminal nerve,sinonasal cavity,cervical lymph nodes,and dural involvement.The most common and remarkable imaging features were T2 hypointensity and diffuse homogeneous contrast enhancement.Conclusions:Head and neck involvement of the IgG4-RD,has specific imaging features that can help with diagnosis.Thus,early diagnosis and better outcomes can be achieved with increasing awareness of these features of this relatively new pathology.展开更多
BACKGROUND Immunoglobulin G4-related disease(IgG4-RD)is a complex immune-mediated condition that causes fibrotic inflammation in several organs.A significant clinical feature of IgG4-RD is hypertrophic pachymeningitis...BACKGROUND Immunoglobulin G4-related disease(IgG4-RD)is a complex immune-mediated condition that causes fibrotic inflammation in several organs.A significant clinical feature of IgG4-RD is hypertrophic pachymeningitis,which manifests as inflammation of the dura mater in intracranial or spinal regions.Although IgG4-RD can affect multiple areas,the spine is a relatively rare site compared to the more frequent involvement of intracranial structures.CASE SUMMARY A 70-year-old male presented to our hospital with a two-day history of fever,altered mental status,and generalized weakness.The initial brain magnetic resonance imaging(MRI)revealed multiple small infarcts across various cerebral regions.On the second day after admission,a physical examination revealed motor weakness in both lower extremities and diminished sensation in the right lower extremity.Electromyographic evaluation revealed findings consistent with acute motor sensory neuropathy.Despite initial management with intravenous immunoglobulin for presumed Guillain-Barrésyndrome,the patient exhibited progressive worsening of motor deficits.On the 45th day of hospitalization,an enhanced MRI of the entire spine,focusing specifically on the thoracic 9 to lumbar 1 vertebral level,raised the suspicion of IgG4-related spinal pachymeningitis.Subsequently,the patient was administered oral prednisolone and participated in a comprehensive rehabilitation program that included gait training and lower extremity strengthening exercises.CONCLUSION IgG4-related spinal pachymeningitis,diagnosed on MRI,was treated with corticosteroids and a structured rehabilitation regimen,leading to significant improvement.展开更多
Photocatalytic H_(2) evolution from seawater splitting presents a promising approach to tackle the fossil energy crisis and mitigate carbon emission due to the abundant source of seawater and sunlight on the earth.How...Photocatalytic H_(2) evolution from seawater splitting presents a promising approach to tackle the fossil energy crisis and mitigate carbon emission due to the abundant source of seawater and sunlight on the earth.However,the development of efficient photocatalysts for seawater splitting remains a formidable challenge.Herein,a 2D/2D ZnIn_(2)S_(4)/WO_(3)(ZIS/WO_(3))heterojunction nanostructure is fabricated to efficiently separate the photoinduced carriers by steering electron transfer from the conduction band minimum of WO_(3) to the valence band maximum of ZIS via constructing internal electric field.Subsequently,plasmonic Au nanoparticles(NPs)as a novel photosensitizer and a reduction cocatalyst are anchored on ZIS/WO_(3) surface to further enhance the optical absorption of ZIS/WO_(3) heterojunction and accelerate the catalytic conversion.The obtained Au/ZIS/WO_(3) photocatalyst exhibits an outstanding H_(2) evolution rate of 2610.6 or 3566.3μmol g^(-1)h~(-1)from seawater splitting under visible or full-spectrum light irradiation,respectively.These rates represent an impressive increase of approximately 7.3-and 6,6-fold compared to those of ZIS under the illumination of the same light source.The unique 2D/2D structure,internal electric field,and plasmonic metal modification together boost the photocatalytic H_(2) evolution rate of Au/ZIS/WO_(3),making it even comparable to H_(2) evolution from pure water splitting.The present work sheds light on the development of efficient photocatalysts for seawater splitting.展开更多
Antennas have come to play a significant role in the reception and transmission of electromagnetic radiation or signals which in turn have improved scientific research in the various areas where they have been used. A...Antennas have come to play a significant role in the reception and transmission of electromagnetic radiation or signals which in turn have improved scientific research in the various areas where they have been used. Astronomy is not left out;as a study of everything beyond earth’s atmosphere, useful signals have to travel great distances to reach us. Hence the need for equipment to detect such signals. The Helical Antenna is known to possess high gain (directivity) and can process signals with any type of orientation/polarization which implies high sensitivity hence the desire to use it. Simulation was done using the legacy 4NEC2 software. The purpose of this paper is to design a circularly polarized helical antenna operating in axial mode that is suitable for detection of neutral hydrogen line emission at the frequency of 1420 MHz and to show how it can be used as a feed for an off-set parabolic dish.展开更多
Compound Mn(N 3) 2(4, 4’ bipy) n having three dimensional structure was obtained with crystallographic data: C 10 H 8N 8Mn ( M r =295.16), tetragonal, space group P4 12 12 1(#99), a=8.220(2), c...Compound Mn(N 3) 2(4, 4’ bipy) n having three dimensional structure was obtained with crystallographic data: C 10 H 8N 8Mn ( M r =295.16), tetragonal, space group P4 12 12 1(#99), a=8.220(2), c=16.918(5) , V=1143.1(5) 3, Z=4, D c =1.715 g/cm -3 , μ =11.07 cm -1 , F(000)=596, R=0.042, R w =0.051, for 590 observable reflections. The special topology structure in the compound occurs from the helical chain consisting of the -Mn-N-N-N-Mn’ unit. The value of χ mT decreases with the decreasing of temperature展开更多
目的研究在没有对照品的情况下鉴定检材中1-(4-氟苯基)-2-(N-吡咯烷基)-1-戊酮[1-(4-fluorophenyl)-2-(1-pyrrolidinyl)pentan-1-one,4-F-α-PVP]类似物1-(4-氟-3甲基苯基)-2-(N-吡咯烷基)-1-戊酮[1-(4-fluoro-3-methyl phenyl)-2-(1-py...目的研究在没有对照品的情况下鉴定检材中1-(4-氟苯基)-2-(N-吡咯烷基)-1-戊酮[1-(4-fluorophenyl)-2-(1-pyrrolidinyl)pentan-1-one,4-F-α-PVP]类似物1-(4-氟-3甲基苯基)-2-(N-吡咯烷基)-1-戊酮[1-(4-fluoro-3-methyl phenyl)-2-(1-pyrrolidinyl)pentan-1-one,4-F-3-Methyl-α-PVP]盐酸盐的方法。方法综合利用直接进样电子电离-质谱(electron ionization-mass spectrometry,EI-MS)、GCMS、电喷雾离子化-高分辨质谱(electrospray ionization-high resolution mass spectrometry,ESI-HRMS)、超高效液相色谱-高分辨串联质谱(ultra-high performance liquid chromatography-high resolution tandem mass spectrometry,UPLC-HRMS/MS)、核磁共振(nuclear magnetic resonance,NMR)、离子色谱和傅里叶变换红外光谱法(Fourier transform infrared spectroscopy,FTIR),实现对检材中未知化合物的结构解析与表征,并对该化合物在EI-MS和UPLC-HRMS/MS两种质谱分析方式下生成碎片离子的裂解机制进行推导。结果通过对检材中化合物的直接进样EI-MS、GC-MS、ESI-HRMS和UPLC-HRMS/MS分析,推断出未知化合物为4-F-α-PVP的结构类似物,可能苯环中多了1个甲基。根据核磁共振氢谱(1H-nuclear magnetic reso⁃nance,1 H-NMR)、核磁共振碳谱(13C-nuclear magnetic resonance,13C-NMR)等分析结果,进一步证明了甲基的位置在苯环的3-位。由于1H-NMR分析中实际氢的个数比4-F-3-Methyl-α-PVP中性分子多1个,推断该化合物以盐形式存在。离子色谱法分析结果表明该化合物含氯离子(含量11.14%~11.16%),结合FTIR对主要官能团信息的结构分析,最终确定该未知化合物为4-F-3-Methyl-α-PVP盐酸盐。结论建立了综合利用EI-MS、GC-MS、ESI-HRMS、UPLC-HRMS/MS、NMR、离子色谱和FTIR鉴定检材中4-F-3-Methyl-α-PVP盐酸盐的方法,将有助于法庭科学实验室在案件中鉴定该物质或其他具有类似结构的化合物。展开更多
Surface-enhanced Raman scattering （SERS） and surface-enhanced resonance Raman scattering （SERRS） spectra of the 1,4-benzenedithiol molecule in the junction of two Au3 clusters have been calculated using density fu...Surface-enhanced Raman scattering （SERS） and surface-enhanced resonance Raman scattering （SERRS） spectra of the 1,4-benzenedithiol molecule in the junction of two Au3 clusters have been calculated using density functional theory （DFT） and time-dependent DFT method. In order to investigate the contribution of charge transfer （CT） enhancement, the wavelengths of incident light are chosen to be at resonance with four representative excited states, which correspond to CT in four different forms. Compared with SERS spectrum, SERRS spectra are enhanced enormously with distinct enhancement factors, which can be attributed to CT resonance in different forms.展开更多
To boost the performance of 4-ary pulse amplitude modulated(PAM) at low signal-to-noise ratio(SNR), bistable stochastic resonance(BSR) system is introduced into digital communications system and get a reliable signal ...To boost the performance of 4-ary pulse amplitude modulated(PAM) at low signal-to-noise ratio(SNR), bistable stochastic resonance(BSR) system is introduced into digital communications system and get a reliable signal detection scheme. In this paper, we first analyse BSR system for different amplitudes of 4-ary PAM signals. The steadystate of the bistable system will be statistically distinct, and the feasibility of the proposed detection scheme is confirmed. On this basis, we present a detailed study on steady-state transitions of the BSR system, and an explicit expression of the bistable system parameters is derived. By setting the bistable system parameters, bistable system, 4-ary PAM signal, and noise reach the resonance state, and the BSR-based detection scheme is implemented. Moreover, we derive an analytical expression to calculate the symbol error rate(SER) of 4-ary PAM signals with the BSR-based detection under additive white Gaussian noise(AWGN). Finally, the simulation results validate that BSR-based detection scheme can improve the detection performance while efficiently reducing the symbol error rate.展开更多
基金Supported by NSFC(Grant Nos.11801148 and 11626089)the Foundation for the Doctor of Henan Polytechnic University(Grant No.B2014-060)。
文摘A{(3,4),4}-fullerene graph S is a 4-regular map on the sphere whose faces are of length 3 or 4.It follows from Euler s formula that the number of triangular faces is eight.A set H of disjoint quadrangular faces of S is called resonant pattern if S has a perfect matching M such that every quadrangular face in H is M-alternating.Let k be a positive integer,S is k-resonant if any i≤k disjoint quadrangular faces of S form a resonant pattern.Moreover,if graph S is k-resonant for any integer k,then S is called maximally resonant.In this paper,we show that the maximally resonant{(3,4),4}-fullerene graphs are S_6,S_8,S_(10)^(2),S_(12)^(2),S_(12)^(4),S_(12)^(5),S_(14)^(3),S_(14)^(5),S_(16)^(3),S_(18)^(5),S_(24)as shown in Fig.1.As a corollary,it is shown that if a{(3,4),4}-fullerene graph is 4-resonant,then it is also maximally resonant.
基金Project supported by the Key-Area Research and Development Program of Guangdong Province,China(Grant No.2019B030330001)the National Natural ScienceFoundation of China(Grant Nos.12025509 and 11904418)+1 种基金the Science and Technology Program of Guangzhou,China(Grant No.201904020024)the Fundamental Research Funds for the Central Universities,China.
文摘Based upon the new designed helical resonator,the resonant radio frequency(RF)for trapping ions can be consec-utively adjusted in a large range(about 12 MHz to 29 MHz)with high Q-factors(above 300).We analyze the helical resonator with a lumped element circuit model and find that the theoretical results fit well with the experimental data.With our resonator system,the resonant frequency near magic RF frequency(where the scalar Stark shift and the second-order Doppler shift due to excess micromotion cancel each other)can be continuously changed at kHz level.For ^(88)Sr^(+) ion,compared to earlier results,the measurement accuracy of magic RF frequency can be improved by an order of magnitude upon rough calculation,and therefore the net micromotion frequency shifts can be further reduced.Also,the differential static scalar polarizability △α0 of clock transition can be experimentally measured more accurately.
基金Supported by Key Laboratory for Advanced Manufacturing Technology and Cutting Tools of the Education Department of Heilongjiang Province,National Natural Science Foundation of China(No.51275345)National NC Science and Technology Major Projects(No.2014ZX04001081)National Engineering and Research Center for Commercial Aircraft Manufacturing(No.SAMC13-JS-15-030)
文摘The hole-making process in stack materials consisting of carbon fiber reinforced plastics （CFRP） and Ti- 6Al-4V remains a critical challenge. In this paper, an experimental study on the helical milling of CFRP/Ti-6Al-4V stacks was conducted by using two different machining strategies. Helical milling strategy Ⅰ machines both materials with identical machining parameters, while machining strategy Ⅱ uses two sets of machining parameters to machine each material. Helical milling performance was evaluated by the following indicators： tool life, cutting forces, hole quality （including diameter deviation, roundness, roughness, and hole edge quality）. The results demonstrate that heli- cal milling strategy 11 outperformed strategy I, leading to longer tool life （up to 48 holes）, smaller cutting forces and better hole quality with higher geometric accuracy and smoother surface finish （Ra≤0.58 μm for Ti-6Al-4V and Ra ≤ 0.81 μm for CFRP）, eliminating the need for reaming or de-burring.
文摘Objective:To evaluate the radiological features of IgG4-related disease(IgG4-RD)in the head and neck region.Methods:In this radiology-based study,radiological features,clinical,laboratory,pathological findings,and prognosis of nine patients with head and neck involvement diagnosed with IgG4-RD were investigated retrospectively.Results:The median age of the patients was 38 years(range:2.5-79 years),and there were six males and three females.The most common symptoms and clinical findings of the patients were eyelid and lacrimal gland swelling,painless exophthalmos,and ophthalmoplegia.The most common site of involvement on MRI was the orbit.Orbital involvement was followed by branches of the trigeminal nerve,sinonasal cavity,cervical lymph nodes,and dural involvement.The most common and remarkable imaging features were T2 hypointensity and diffuse homogeneous contrast enhancement.Conclusions:Head and neck involvement of the IgG4-RD,has specific imaging features that can help with diagnosis.Thus,early diagnosis and better outcomes can be achieved with increasing awareness of these features of this relatively new pathology.
文摘BACKGROUND Immunoglobulin G4-related disease(IgG4-RD)is a complex immune-mediated condition that causes fibrotic inflammation in several organs.A significant clinical feature of IgG4-RD is hypertrophic pachymeningitis,which manifests as inflammation of the dura mater in intracranial or spinal regions.Although IgG4-RD can affect multiple areas,the spine is a relatively rare site compared to the more frequent involvement of intracranial structures.CASE SUMMARY A 70-year-old male presented to our hospital with a two-day history of fever,altered mental status,and generalized weakness.The initial brain magnetic resonance imaging(MRI)revealed multiple small infarcts across various cerebral regions.On the second day after admission,a physical examination revealed motor weakness in both lower extremities and diminished sensation in the right lower extremity.Electromyographic evaluation revealed findings consistent with acute motor sensory neuropathy.Despite initial management with intravenous immunoglobulin for presumed Guillain-Barrésyndrome,the patient exhibited progressive worsening of motor deficits.On the 45th day of hospitalization,an enhanced MRI of the entire spine,focusing specifically on the thoracic 9 to lumbar 1 vertebral level,raised the suspicion of IgG4-related spinal pachymeningitis.Subsequently,the patient was administered oral prednisolone and participated in a comprehensive rehabilitation program that included gait training and lower extremity strengthening exercises.CONCLUSION IgG4-related spinal pachymeningitis,diagnosed on MRI,was treated with corticosteroids and a structured rehabilitation regimen,leading to significant improvement.
基金supported by the National Natural Science Foundation of China(21872104,21501131,21978216 and 22272082)the Natural Science Foundation of Tianjin for Distinguished Young Scholar(20JCJQJC00150)the Analytical&Testing Center of Tiangong University for PL work。
文摘Photocatalytic H_(2) evolution from seawater splitting presents a promising approach to tackle the fossil energy crisis and mitigate carbon emission due to the abundant source of seawater and sunlight on the earth.However,the development of efficient photocatalysts for seawater splitting remains a formidable challenge.Herein,a 2D/2D ZnIn_(2)S_(4)/WO_(3)(ZIS/WO_(3))heterojunction nanostructure is fabricated to efficiently separate the photoinduced carriers by steering electron transfer from the conduction band minimum of WO_(3) to the valence band maximum of ZIS via constructing internal electric field.Subsequently,plasmonic Au nanoparticles(NPs)as a novel photosensitizer and a reduction cocatalyst are anchored on ZIS/WO_(3) surface to further enhance the optical absorption of ZIS/WO_(3) heterojunction and accelerate the catalytic conversion.The obtained Au/ZIS/WO_(3) photocatalyst exhibits an outstanding H_(2) evolution rate of 2610.6 or 3566.3μmol g^(-1)h~(-1)from seawater splitting under visible or full-spectrum light irradiation,respectively.These rates represent an impressive increase of approximately 7.3-and 6,6-fold compared to those of ZIS under the illumination of the same light source.The unique 2D/2D structure,internal electric field,and plasmonic metal modification together boost the photocatalytic H_(2) evolution rate of Au/ZIS/WO_(3),making it even comparable to H_(2) evolution from pure water splitting.The present work sheds light on the development of efficient photocatalysts for seawater splitting.
文摘Antennas have come to play a significant role in the reception and transmission of electromagnetic radiation or signals which in turn have improved scientific research in the various areas where they have been used. Astronomy is not left out;as a study of everything beyond earth’s atmosphere, useful signals have to travel great distances to reach us. Hence the need for equipment to detect such signals. The Helical Antenna is known to possess high gain (directivity) and can process signals with any type of orientation/polarization which implies high sensitivity hence the desire to use it. Simulation was done using the legacy 4NEC2 software. The purpose of this paper is to design a circularly polarized helical antenna operating in axial mode that is suitable for detection of neutral hydrogen line emission at the frequency of 1420 MHz and to show how it can be used as a feed for an off-set parabolic dish.
文摘Compound Mn(N 3) 2(4, 4’ bipy) n having three dimensional structure was obtained with crystallographic data: C 10 H 8N 8Mn ( M r =295.16), tetragonal, space group P4 12 12 1(#99), a=8.220(2), c=16.918(5) , V=1143.1(5) 3, Z=4, D c =1.715 g/cm -3 , μ =11.07 cm -1 , F(000)=596, R=0.042, R w =0.051, for 590 observable reflections. The special topology structure in the compound occurs from the helical chain consisting of the -Mn-N-N-N-Mn’ unit. The value of χ mT decreases with the decreasing of temperature
文摘目的研究在没有对照品的情况下鉴定检材中1-(4-氟苯基)-2-(N-吡咯烷基)-1-戊酮[1-(4-fluorophenyl)-2-(1-pyrrolidinyl)pentan-1-one,4-F-α-PVP]类似物1-(4-氟-3甲基苯基)-2-(N-吡咯烷基)-1-戊酮[1-(4-fluoro-3-methyl phenyl)-2-(1-pyrrolidinyl)pentan-1-one,4-F-3-Methyl-α-PVP]盐酸盐的方法。方法综合利用直接进样电子电离-质谱(electron ionization-mass spectrometry,EI-MS)、GCMS、电喷雾离子化-高分辨质谱(electrospray ionization-high resolution mass spectrometry,ESI-HRMS)、超高效液相色谱-高分辨串联质谱(ultra-high performance liquid chromatography-high resolution tandem mass spectrometry,UPLC-HRMS/MS)、核磁共振(nuclear magnetic resonance,NMR)、离子色谱和傅里叶变换红外光谱法(Fourier transform infrared spectroscopy,FTIR),实现对检材中未知化合物的结构解析与表征,并对该化合物在EI-MS和UPLC-HRMS/MS两种质谱分析方式下生成碎片离子的裂解机制进行推导。结果通过对检材中化合物的直接进样EI-MS、GC-MS、ESI-HRMS和UPLC-HRMS/MS分析,推断出未知化合物为4-F-α-PVP的结构类似物,可能苯环中多了1个甲基。根据核磁共振氢谱(1H-nuclear magnetic reso⁃nance,1 H-NMR)、核磁共振碳谱(13C-nuclear magnetic resonance,13C-NMR)等分析结果,进一步证明了甲基的位置在苯环的3-位。由于1H-NMR分析中实际氢的个数比4-F-3-Methyl-α-PVP中性分子多1个,推断该化合物以盐形式存在。离子色谱法分析结果表明该化合物含氯离子(含量11.14%~11.16%),结合FTIR对主要官能团信息的结构分析,最终确定该未知化合物为4-F-3-Methyl-α-PVP盐酸盐。结论建立了综合利用EI-MS、GC-MS、ESI-HRMS、UPLC-HRMS/MS、NMR、离子色谱和FTIR鉴定检材中4-F-3-Methyl-α-PVP盐酸盐的方法,将有助于法庭科学实验室在案件中鉴定该物质或其他具有类似结构的化合物。
基金This work was supported by the National Natural Science Foundation of China （No.10604012, No.10974023, No.10874234, No.20703064, No.90923003）, the National Basic Research Project of China （No.2009CB930Y01）, and the Fundamental Research Funds for the Central Universities （No.DUT10LK03）.
文摘Surface-enhanced Raman scattering （SERS） and surface-enhanced resonance Raman scattering （SERRS） spectra of the 1,4-benzenedithiol molecule in the junction of two Au3 clusters have been calculated using density functional theory （DFT） and time-dependent DFT method. In order to investigate the contribution of charge transfer （CT） enhancement, the wavelengths of incident light are chosen to be at resonance with four representative excited states, which correspond to CT in four different forms. Compared with SERS spectrum, SERRS spectra are enhanced enormously with distinct enhancement factors, which can be attributed to CT resonance in different forms.
基金supported by the National Natural Science Foundation of China (61631015, 61501354, 61501356, and 61573202)the Fundamental Research Funds of the Ministry of Education (7215433803)+5 种基金the Foundation of State Key Laboratory of Integrated Services Networks (ISN1101002)Higher School Subject Innovation Engineering Plan (B08038)Science and Technology Innovation Team Key Plan of Shaanxi Province (2016KCT-01)The Fundamental Research Funds of the Ministry of Education, China (Grant No. JB160101)The Key Laboratory Foundation of Ministry of Industry and Information Technology (KF20181912)China Postdoctoral Science Foundation (2018M631122)
文摘To boost the performance of 4-ary pulse amplitude modulated(PAM) at low signal-to-noise ratio(SNR), bistable stochastic resonance(BSR) system is introduced into digital communications system and get a reliable signal detection scheme. In this paper, we first analyse BSR system for different amplitudes of 4-ary PAM signals. The steadystate of the bistable system will be statistically distinct, and the feasibility of the proposed detection scheme is confirmed. On this basis, we present a detailed study on steady-state transitions of the BSR system, and an explicit expression of the bistable system parameters is derived. By setting the bistable system parameters, bistable system, 4-ary PAM signal, and noise reach the resonance state, and the BSR-based detection scheme is implemented. Moreover, we derive an analytical expression to calculate the symbol error rate(SER) of 4-ary PAM signals with the BSR-based detection under additive white Gaussian noise(AWGN). Finally, the simulation results validate that BSR-based detection scheme can improve the detection performance while efficiently reducing the symbol error rate.
