Optical frequency combs,as powerful tools for precision spectroscopy and research into optical frequency standards,have driven continuous progress and significant breakthroughs in applications such as time-frequency t...Optical frequency combs,as powerful tools for precision spectroscopy and research into optical frequency standards,have driven continuous progress and significant breakthroughs in applications such as time-frequency transfer,measurement of fundamental physical constants,and high-precision ranging,achieving a series of milestone results in ground-based environments.With the continuous maturation and evolution of femtosecond lasers and related technologies,optical frequency combs are moving from ground-based applications to astronomical and space-based applications,playing an increasingly important role in atomic clocks,exoplanet observations,gravitational wave measurements,and other areas.This paper,focusing on astronomical and space-based applications,reviews research progress on astronomical frequency combs,optical clock time-frequency networks,gravitational waves,dark matter measurement,dual-comb large-scale absolute ranging,and high-resolution atmospheric spectroscopy.With enhanced performance and their gradual application in the field of space-based research,optical frequency combs will undoubtedly provide more powerful support for astronomical science and cosmic exploration in the future.展开更多
PPG-5-Ceteth-20 is a multifunction raw material.PPG-5-Ceteth-20 has a wide range of application in skin care and hair care products.The purpose of this study was to evaluate the performance of PPG-5-Ceteth-20.The resu...PPG-5-Ceteth-20 is a multifunction raw material.PPG-5-Ceteth-20 has a wide range of application in skin care and hair care products.The purpose of this study was to evaluate the performance of PPG-5-Ceteth-20.The results shown that PPG-5-Ceteth-20 can improve hair combing,softness and smoothing in the hair care product.In additional,it can improve foam stability and compactness,and it doesn’t affect the transparency of the hair care product.展开更多
We have proposed and constructed a few-mode fiber(FMF)-based comb filter realized by dislocation splicing a fewmode long-period fiber grating(FM-LPFG) with a single-mode fiber(SMF). From an all-fiber laser with a FMF-...We have proposed and constructed a few-mode fiber(FMF)-based comb filter realized by dislocation splicing a fewmode long-period fiber grating(FM-LPFG) with a single-mode fiber(SMF). From an all-fiber laser with a FMF-based comb filter, the generation of switchable single-, dual-, triple-, and quadruple-wavelength continuous light has been achieved.Moreover, wavelength switchable mode-locked pulses have been obtained with the increased pump power. In the experiment, the output wavelength of the mode-locked fiber laser was changed from 1567.72 nm to 1571.04 nm, while the signal-to-noise(SNR) ratio was maintained above 61 d B. The switchable multiwavelength continuous wave(CW) and mode-locked all-fiber lasers have potentially important applications for fiber sensing, wavelength-division multiplexing(WDM) and signal processing.展开更多
Frequency-comb emission via high-order harmonic generation(HHG)provides an alternative method for the coherent vacuum ultraviolet(VUV)and extreme ultraviolet(XUV)radiation at ultrahigh repetition rates.In particular,t...Frequency-comb emission via high-order harmonic generation(HHG)provides an alternative method for the coherent vacuum ultraviolet(VUV)and extreme ultraviolet(XUV)radiation at ultrahigh repetition rates.In particular,the temporal and spectral features of the HHG were shown to carry profound insight into frequency-comb emission dynamics.Here we present an ab initio investigation of the temporal and spectral coherence of the frequency comb emitted in HHG of He atom driven by few-cycle pulse trains.We find that the emission of frequency combs features a destructive and constructive coherences caused by the phase interference of HHG,leading to suppression and enhancement of frequency-comb emission.The results reveal intriguing and substantially different nonlinear optical response behaviors for frequency-comb emission via HHG.The dynamical origin of frequency-comb emission is clarified by analyzing the phase coherence in HHG processes in detail.Our results provide fresh insight into the experimental realization of selective enhancement of frequency comb in the VUV–XUV regimes.展开更多
The fire-bellied newt genus Cynops contains ten known species distributed in China and Japan in East Asia.In this work,two new Cynops species are described,namely Cynops jiaoren sp.nov.distributed in northern Guangdon...The fire-bellied newt genus Cynops contains ten known species distributed in China and Japan in East Asia.In this work,two new Cynops species are described,namely Cynops jiaoren sp.nov.distributed in northern Guangdong and Cynops maguae sp.nov.distributed in eastern Jiangxi.The two new species can be distinctly distinguished from their congeners by the independent phylogenetic placements and a combination of morphological characteristics.The discovery of these two new species in the Southeast Chinese Hilly Area,where half of congeners occur,increases the known diversity of Cynops,and indicates unresolved relationships among the species in southeastern China.Further discussions on the taxonomic status of Cynops cyanurus are also provided.展开更多
BACKGROUND Systemic lupus erythematosus(SLE)is a multisystem autoimmune disease that can affect the gastrointestinal tract.Most cases of lupus enteritis(LE)involve the small intestine,while the involvement of the whol...BACKGROUND Systemic lupus erythematosus(SLE)is a multisystem autoimmune disease that can affect the gastrointestinal tract.Most cases of lupus enteritis(LE)involve the small intestine,while the involvement of the whole colon and rectum without the small intestine being affected is extremely rare.CASE SUMMARY A 35-year-old woman was diagnosed with colorectal LE after initially presenting with intermittent abdominal pain and vomiting for two months.She had a regular medication history for five years following the diagnosis of SLE but had been irregular in taking medications,which may have contributed to the onset of LE and led to her current hospital admission.According to the 2019 Classification criteria for SLE of the European League Against Rheumatism/American College of Rheumatology,this case scored 14.Additionally,abdominal computed tomography revealed significant wall edema of the colon and rectum,ischemia and hyperemia of the ascending colon intestinal wall,mesenteric vessel engorgement,increased mesangial fat attenuation,ascites,and bilateral ureter-hydronephrosis,all indicative of colon and rectum LE.Laboratory tests also showed lower levels of complement C3 and C4,with an antinuclear antibody titer of 1:100.Overall,it was clear that this case involved the colon and rectum without affecting the small intestine,representing a rare manifestation of SLE.The patient received treatment with 10 mg of methylprednisolone sodium succinate,100 mL of 0.9%sodium chloride,hydroxychloroquine(100 mg),and nutrition support.After one week of methylprednisolone and hydroxychloroquine therapy,her SLE symptoms and disease activity improved significantly.CONCLUSION Although colorectal LE without small intestine involvement is very rare,early diagnosis and excellent management with corticosteroids prevented the need for surgical intervention.Physicians should be aware of colorectal LE without small intestine involvement as a manifestation of lupus flare.展开更多
This paper presents a novel approach to improve aliasing rejection in comb-based decimation filters. The method is established on certain palindromic polynomials with all zeros on the unit circle and the sharpening te...This paper presents a novel approach to improve aliasing rejection in comb-based decimation filters. The method is established on certain palindromic polynomials with all zeros on the unit circle and the sharpening technique. As a result, aliasing rejection and the passband characteristic are improved. The method is illustrated with various examples and compared with the methods from the literature. .展开更多
A new well test model is developed for the hydraulic fractured well in coalbed by considering the following aspects： methane desorption phenomena, finite conductivity vertical fractures, and asymmetry of the fracture...A new well test model is developed for the hydraulic fractured well in coalbed by considering the following aspects： methane desorption phenomena, finite conductivity vertical fractures, and asymmetry of the fracture about the well. A new parameter is introduced to describe the storage of the fracture, which is named as a combined fracture storage. Another new concept called the fracture asymmetry coefficient is used to define the asymmetry of the fracture about the well. Finite element method （FEM） is used to solve the new mathematical model. The well test type curves and pressure fields are obtained and analyzed. The effects of the combined fracture storage, desorption factor, fracture conductivity, and fracture asymmetry coefficient on the well test type curves are discussed in detail. In order to verify the new model, a set of field well test data is analyzed.展开更多
基金support of the National Natural Sci-ence Foundation of China(NSFC)(62305373)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA1502040404,XDB2101040004).
文摘Optical frequency combs,as powerful tools for precision spectroscopy and research into optical frequency standards,have driven continuous progress and significant breakthroughs in applications such as time-frequency transfer,measurement of fundamental physical constants,and high-precision ranging,achieving a series of milestone results in ground-based environments.With the continuous maturation and evolution of femtosecond lasers and related technologies,optical frequency combs are moving from ground-based applications to astronomical and space-based applications,playing an increasingly important role in atomic clocks,exoplanet observations,gravitational wave measurements,and other areas.This paper,focusing on astronomical and space-based applications,reviews research progress on astronomical frequency combs,optical clock time-frequency networks,gravitational waves,dark matter measurement,dual-comb large-scale absolute ranging,and high-resolution atmospheric spectroscopy.With enhanced performance and their gradual application in the field of space-based research,optical frequency combs will undoubtedly provide more powerful support for astronomical science and cosmic exploration in the future.
文摘PPG-5-Ceteth-20 is a multifunction raw material.PPG-5-Ceteth-20 has a wide range of application in skin care and hair care products.The purpose of this study was to evaluate the performance of PPG-5-Ceteth-20.The results shown that PPG-5-Ceteth-20 can improve hair combing,softness and smoothing in the hair care product.In additional,it can improve foam stability and compactness,and it doesn’t affect the transparency of the hair care product.
基金supported by the National Natural Science Foundation of China (Grant Nos. 91950105 and 62175116)the 1311 talent plan of Nanjing University of Posts and Telecommunications。
文摘We have proposed and constructed a few-mode fiber(FMF)-based comb filter realized by dislocation splicing a fewmode long-period fiber grating(FM-LPFG) with a single-mode fiber(SMF). From an all-fiber laser with a FMF-based comb filter, the generation of switchable single-, dual-, triple-, and quadruple-wavelength continuous light has been achieved.Moreover, wavelength switchable mode-locked pulses have been obtained with the increased pump power. In the experiment, the output wavelength of the mode-locked fiber laser was changed from 1567.72 nm to 1571.04 nm, while the signal-to-noise(SNR) ratio was maintained above 61 d B. The switchable multiwavelength continuous wave(CW) and mode-locked all-fiber lasers have potentially important applications for fiber sensing, wavelength-division multiplexing(WDM) and signal processing.
基金the National Natural Science Foundation of China(Grant Nos.12074239 and 91850209)the Natural Science Foundation of Guangdong Province,China(Grant Nos.2020A1515010927 and 2020ST084)+1 种基金the Fund from the Department of Education of Guangdong Province,China(Grant Nos.2019KTSCX038 and 2020KCXTD012)the Fund from Shantou University(Grant No.NTF18030).
文摘Frequency-comb emission via high-order harmonic generation(HHG)provides an alternative method for the coherent vacuum ultraviolet(VUV)and extreme ultraviolet(XUV)radiation at ultrahigh repetition rates.In particular,the temporal and spectral features of the HHG were shown to carry profound insight into frequency-comb emission dynamics.Here we present an ab initio investigation of the temporal and spectral coherence of the frequency comb emitted in HHG of He atom driven by few-cycle pulse trains.We find that the emission of frequency combs features a destructive and constructive coherences caused by the phase interference of HHG,leading to suppression and enhancement of frequency-comb emission.The results reveal intriguing and substantially different nonlinear optical response behaviors for frequency-comb emission via HHG.The dynamical origin of frequency-comb emission is clarified by analyzing the phase coherence in HHG processes in detail.Our results provide fresh insight into the experimental realization of selective enhancement of frequency comb in the VUV–XUV regimes.
基金supported by DFGP Project of Fauna of Guangdong-202115Nanling National Park Construction Project(No.ZD22-ZC016AG)+1 种基金2022 Wildlife Monitoring Projects of the Guangdong Forestry Bureauthe National Animal Collection Resource Center,China。
文摘The fire-bellied newt genus Cynops contains ten known species distributed in China and Japan in East Asia.In this work,two new Cynops species are described,namely Cynops jiaoren sp.nov.distributed in northern Guangdong and Cynops maguae sp.nov.distributed in eastern Jiangxi.The two new species can be distinctly distinguished from their congeners by the independent phylogenetic placements and a combination of morphological characteristics.The discovery of these two new species in the Southeast Chinese Hilly Area,where half of congeners occur,increases the known diversity of Cynops,and indicates unresolved relationships among the species in southeastern China.Further discussions on the taxonomic status of Cynops cyanurus are also provided.
文摘BACKGROUND Systemic lupus erythematosus(SLE)is a multisystem autoimmune disease that can affect the gastrointestinal tract.Most cases of lupus enteritis(LE)involve the small intestine,while the involvement of the whole colon and rectum without the small intestine being affected is extremely rare.CASE SUMMARY A 35-year-old woman was diagnosed with colorectal LE after initially presenting with intermittent abdominal pain and vomiting for two months.She had a regular medication history for five years following the diagnosis of SLE but had been irregular in taking medications,which may have contributed to the onset of LE and led to her current hospital admission.According to the 2019 Classification criteria for SLE of the European League Against Rheumatism/American College of Rheumatology,this case scored 14.Additionally,abdominal computed tomography revealed significant wall edema of the colon and rectum,ischemia and hyperemia of the ascending colon intestinal wall,mesenteric vessel engorgement,increased mesangial fat attenuation,ascites,and bilateral ureter-hydronephrosis,all indicative of colon and rectum LE.Laboratory tests also showed lower levels of complement C3 and C4,with an antinuclear antibody titer of 1:100.Overall,it was clear that this case involved the colon and rectum without affecting the small intestine,representing a rare manifestation of SLE.The patient received treatment with 10 mg of methylprednisolone sodium succinate,100 mL of 0.9%sodium chloride,hydroxychloroquine(100 mg),and nutrition support.After one week of methylprednisolone and hydroxychloroquine therapy,her SLE symptoms and disease activity improved significantly.CONCLUSION Although colorectal LE without small intestine involvement is very rare,early diagnosis and excellent management with corticosteroids prevented the need for surgical intervention.Physicians should be aware of colorectal LE without small intestine involvement as a manifestation of lupus flare.
文摘This paper presents a novel approach to improve aliasing rejection in comb-based decimation filters. The method is established on certain palindromic polynomials with all zeros on the unit circle and the sharpening technique. As a result, aliasing rejection and the passband characteristic are improved. The method is illustrated with various examples and compared with the methods from the literature. .
基金Project supported by the National Science and Technology Major Project of China(No.2011ZX05038003)the Science and Technology Project of PetroChina Company Limited(No.2010E-2205)
文摘A new well test model is developed for the hydraulic fractured well in coalbed by considering the following aspects： methane desorption phenomena, finite conductivity vertical fractures, and asymmetry of the fracture about the well. A new parameter is introduced to describe the storage of the fracture, which is named as a combined fracture storage. Another new concept called the fracture asymmetry coefficient is used to define the asymmetry of the fracture about the well. Finite element method （FEM） is used to solve the new mathematical model. The well test type curves and pressure fields are obtained and analyzed. The effects of the combined fracture storage, desorption factor, fracture conductivity, and fracture asymmetry coefficient on the well test type curves are discussed in detail. In order to verify the new model, a set of field well test data is analyzed.
