To address the challenges posed by tunnel construction in the alpine region,silica fume mixed concrete is commonly used as a construction material.The correlation between silica fume content and the lining life requir...To address the challenges posed by tunnel construction in the alpine region,silica fume mixed concrete is commonly used as a construction material.The correlation between silica fume content and the lining life requires immediate investigation.In view of this phenomenon,the durability of unit lining concrete is predicted by analyzing three key indicators:carbonation depth,relative dynamic elastic modulus,and residual quality.This prediction is achieved by integrating the Entropy Weight Method,Grey theory life prediction model and BP artificial neural networks using data from tests and predictions of these indicators.Then,the Entropy Weight-Grey theory-BP Network Model is compared with other methods to analyze the predicted life.Finally,verify the sci-entificity of this model,and the optimum silica fume content of unit concrete lining is verified.The results showed,1)The addition of silica fume will accelerate the carbonization of unit concrete lining,and slow down the freeze-thaw cycle and sulfate erosion.2)The utilization of artificial neural networks is essential for enhancing the realism of the data,as it emphasizes the significance of silica fume content.3)Silica fume content of 10%results in the longest life and is the most suitable for lining construction.4)A comparison between single-factor and multi-factor predictions indicates that the multi-factor approach yields a longer maximum life.This improvement can be attributed to the inclusion of additional factors,such as freeze-thaw cycles and carbonation,which enhance the predicted life when employing these methods.In conclusion,the Entropy Weight-Grey Theory-BP Network life prediction Model is well-suited for tunnel lining in the alpine sulfate area of northwest China.展开更多
With the generation of both localised thermal and vibration in incremental sheet forming(ISF)by novel tool designs,rotational vibration assisted ISF(RV-ISF)can achieve significant force reduction and material softenin...With the generation of both localised thermal and vibration in incremental sheet forming(ISF)by novel tool designs,rotational vibration assisted ISF(RV-ISF)can achieve significant force reduction and material softening.However,the combined thermal and vibration softening in RV-ISF is unclear.By evaluating the similarities and differences of friction stir ISF(FS-ISF)and RV-ISF,this study develops a novel approach to decouple and quantify the thermal and vibration softening effects in RV-ISF of AZ31B-H24,providing new insights into underlying thermal and vibration softening mechanism.Experimental results reveal that in RV-ISF of AZ31B-H24 the thermal softening due to frictional heating dominates with 45∼65%of softening,while the vibration effect only contributes up to 15%of softening,from the conventional ISF,depending on the tool designs and tool rotational speed.The double-offset tool(T2)produces greater vibration softening than the three-groove tool(T3)owing to the higher vibration amplitude of the T2 tool.An increase in tool rotational speed primarily enhances thermal softening with only marginal changes to the vibration effect.Microstructural analysis suggests that with average grain size of 0.94μm at the top layer,RV-ISF with T3 and 3000 rpm is more effective for microstructure refinement than that by FS-ISF,especially on the tool-sheet contact surface,which confirms the occurrence of surface shearing.This refinement is a result of the reduced recrystallisation degree,71.8%at the top bottom layer.Compared with FS-ISF,RV-ISF can lead to not only higher geometrically necessary dislocation density,but also higher fraction of low-angle grain boundaries,indicating that softening mechanism due to localised vibration effect is resulted from the enhanced rearrangement and annihilation of dislocations.These findings contribute to new understanding of the thermal and vibration softening effects in RV-ISF of AZ31B-H24 and offer a theoretical foundation for the tool design and process optimisation.展开更多
The Cambrian Qiongzhusi Formation in the Sichuan Basin harbors significant potential for shale gas harvesting.However,systematic disparities in mineral composition and reservoir architecture have been observed between...The Cambrian Qiongzhusi Formation in the Sichuan Basin harbors significant potential for shale gas harvesting.However,systematic disparities in mineral composition and reservoir architecture have been observed between intra-and extra-trough reservoirs within the Deyang-Anyue Rift Trough.These variations were primarily determined by divergences in the sedimentary environments developed during the evolution of the rift trough,which were a main factor in fostering the heterogeneous distribution of shale gas enrichment found today.However,the genetic mechanisms that govern reservoir heterogeneity across distinct structural domains(intra-trough,trough margin,and extra-trough)remain poorly understood,particularly regarding the coupling relationships between depositional environments,reservoir characteristics,and gas-bearing properties.This study adopts a multidisciplinary approach to investigating this issue that integrates core analysis,well-log interpretations,and geochemical data.Through systematic comparisons conducted using X-ray diffraction mineralogy,organic carbon quantification,and spontaneous imbibition experiments,we characterize the mineral assemblages,organic geochemical signatures,and pore structures found across the three structural domains of the Deyang-Anyue Rift Trough.The key findings are as follows:(1)The depositional environment is the main influence on reservoir distribution and organic matter enrichment,with intra-trough shales exhibiting a higher abundance of organic matter than their trough-margin and extra-trough counterparts.(2)Enhanced brittleness in intra-trough zones correlates with the predominance of biogenic silica therein.(3)Synergistic organic-inorganic interactions govern pore system development.(4)Gas-bearing capacity is jointly determined by effective porosity and organic matter content.These findings establish the rift trough as a preferential exploration target,providing critical geological guidance for optimizing shale gas exploration strategies in the Cambrian Qiongzhusi Formation.展开更多
The prevalence of colorectal cancer (CRC) and type 2 diabetes mellitus (T2DM) isincreasing globally. It is rarely noticed that the incidence of CRC is higher inpatients with T2DM. What needs to be mentioned is that me...The prevalence of colorectal cancer (CRC) and type 2 diabetes mellitus (T2DM) isincreasing globally. It is rarely noticed that the incidence of CRC is higher inpatients with T2DM. What needs to be mentioned is that metformin, a commonlyused clinical drug for T2DM, attracts scholars’ attention because of its benefits inlowering the risk of developing CRC. Hence, we try to find the common groundsof initiation of T2DM and CRC and the reason why metformin reduces the risk ofCRC in patients with T2DM. We noticed consistent changes of gut microbiota,such as elevated Bacteroides, Prevotella and Bifidobacterium and depressedFirmicutes and Lactobacillus. Furthermore, many studies in recent years haveproved that the efficacy of metformin, such as improving blood glucose, dependson the gut microbiota. Coincidentally, the progression of CRC is inseparable fromthe contributions of gut microbiota. Therefore, we first proposed the concept ofthe metformin-gut microbiota–CRC (in T2DM) axis to explain the effect ofmetformin in reducing CRC in patients with T2DM. In this review, we elaboratedthe new concept and its potential clinical application value.展开更多
Phytochemical investigation of the aerial parts of Leonurus japonicus led to the isolation of one new labdane diterpenoid, leojaponin D （1） and two new ionone derivatives, leojaponones A and B （2 and 3）, together ...Phytochemical investigation of the aerial parts of Leonurus japonicus led to the isolation of one new labdane diterpenoid, leojaponin D （1） and two new ionone derivatives, leojaponones A and B （2 and 3）, together with seven known diterpenoids （4-10）. Their structures were elucidated by extensive 1D and 2D NMR spectroscopic data and by comparison with data reported in the literature. Selected isolates were evaluated their effects on lurkat IL2 secretino.展开更多
Objective: Meta-analysis was conducted to assess whether combination of traditional Chinese and western medicine could enhance clinical outcomes compared to single western medicine in the treatment of acute pancreatit...Objective: Meta-analysis was conducted to assess whether combination of traditional Chinese and western medicine could enhance clinical outcomes compared to single western medicine in the treatment of acute pancreatitis (AP). Methods: This systematic review will include prospective and retrospective comparative studies in all languages and evaluate the clinical efficacy of integrated traditional Chinese and western medicine versus single western medicine in treatment AP. Animal studies will not be considered. Published articles were acquired from Jan. 2001 to Dec. 2017 by a comprehensive search in Chinese National Knowledge Infrastructure database (CNKI), Chinese WANFANG database. Exclusion criteria were non-comparative studies, hybrid treatment. The main points include clinical efficacy;carefully evaluating and reviewing the literature and filtering the literature according to inclusion criteria and exclusion criteria. Statistical analyses were performed using software Review Manager (Version 5.0). Publication biases of main results were examined by Stata 12.0. Results: 1262 cases of 1342 cases were effective and the effective rate reaches 94.04% in the group of integrated traditional Chinese and western medicine, while 949 cases of 1223 cases were effective and its effective rate can be up to 77.60% in the group of single western medicine (P > 0.05%, I2 = 0%, Odds Ratio (OR) = 4.98, 95% CI = 3. 79 - 6.54, P Conclusion: These results suggest that the therapeutic effects of integrated traditional Chinese and Western medicine on AP are better in treatment of AP than that of western medicine alone.展开更多
Based on the asymmetric characteristic of skeleton curve obtained from dynamic tests on soils,a function with double asymptotes is proposed for describing the dynamic constitutive relations of soils.The hysteresis loo...Based on the asymmetric characteristic of skeleton curve obtained from dynamic tests on soils,a function with double asymptotes is proposed for describing the dynamic constitutive relations of soils.The hysteresis loops observed during unloading and reloading show the same form as the skeleton curve and are constructed by taking the ultimate stress as the corresponding asymptote.The coeffcient of initial unloading modulus is used to ensure that the constructed hysteresis loop fts well with the experimental data.Then,a new dynamic constitutive model considering the asymmetry of skeleton curve is elaborated.The verifcation tests on saturated Nanjing fne sand are performed using a hollow cylinder apparatus to verify the applicability of the UD model.It is found that the predicted curves by the UD model agree well with the test data.展开更多
BACKGROUND Eosinophilic granulomatosis with polyangiitis(EGPA),formerly known as Churg-Strauss syndrome,is a rare form of anti-neutrophil cytoplasmic antibodyassociated vasculitis characterized by asthma,vasculitis,an...BACKGROUND Eosinophilic granulomatosis with polyangiitis(EGPA),formerly known as Churg-Strauss syndrome,is a rare form of anti-neutrophil cytoplasmic antibodyassociated vasculitis characterized by asthma,vasculitis,and eosinophilia.CASE SUMMARY We report an atypical case of EGPA in a 20-year-old female patient.Unlike previously reported cases of EGPA,this patient’s initial symptom was asthma associated with a respiratory infection.This was followed by Loeffler endocarditis and cardiac insufficiency.She received treatment with methylprednisolone sodium succinate,low molecular weight heparin,recombinant human brain natriuretic peptide,furosemide,cefoperazone sodium/sulbactam sodium,and acyclovir.Despite prophylactic anticoagulation,she developed a large right ventricular thrombus.EGPA diagnosis was confirmed based on ancillary test results and specialty consultations.Subsequent treatment included mycophenolate mofetil.Her overall condition improved significantly after treatment,as evidenced by decreased peripheral blood eosinophils and cardiac markers.She was discharged after 17 d.Her most recent follow-up showed normal peripheral blood eosinophil levels,restored cardiac function,and a reduced cardiac mural thrombus size.CONCLUSION This case illustrates the swift progression of EGPA and underscores the significance of early detection and immediate intervention to ensure a favorable prognosis.展开更多
The novel vertically standing Pt Se2 film on transparent quartz was prepared by selenization of platinum film deposited by the magnetron sputtering method, and an Nd:Lu VO4 passively mode-locked solid-state laser was ...The novel vertically standing Pt Se2 film on transparent quartz was prepared by selenization of platinum film deposited by the magnetron sputtering method, and an Nd:Lu VO4 passively mode-locked solid-state laser was realized by using the fabricated Pt Se2 film as a saturable absorber. The X-ray diffraction pattern and Raman spectrum of the film indicate its good crystallinity with a layered structure. The thickness of Pt Se2 film is measured to be 24 nm according to the cross-section height profile of the atomic force microscope image. Highresolution transmission electron microscopy images clearly demonstrate its vertically standing structure with an interlayer distance of 0.54 nm along the c-axis direction. The modulation depth(ΔT) and saturation fluence(Φs)of Pt Se2 film are measured to be 12.6% and 17.1 μJ∕cm2, respectively. The obtained mode-locked laser spectrum has a central wavelength of 1066.573 nm, with a 3 d B bandwidth of 0.106 nm. The transform limited pulse width of the mode-locked laser was calculated to be 15.8 ps. A maximum average output power of 180 m W with a working repetition rate of 61.3 MHz is obtained. To the best of our knowledge, this is the first report of the generation of ultrafast mode-locked laser pulses by using layered Pt Se2 as a saturable absorber.展开更多
Dear Editor,There is a growing body of evidence that the human rhomboid family-1 gene(RHBDF1)plays an important role in the modulation of tumor inflammatory(Supplementary Fig.la)and hypoxic microenvironment.
Spaceborne photon-counting LiDAR is significantly affected by noise,and existing denoising algorithms cannot be universally adapted to different surface types and topographies under all observation conditions.Accordin...Spaceborne photon-counting LiDAR is significantly affected by noise,and existing denoising algorithms cannot be universally adapted to different surface types and topographies under all observation conditions.Accordingly,a new denoising method is presented to extract signal photons adaptively.The method includes two steps.First,the local neighborhood radius is calculated according to photons’density,then thefirst-step denoising process is completed via photons’curvature feature based on KNN search and covariance matrix.Second,the local photonfiltering direction and threshold are obtained based on thefirst-step denoising results by RANSAC and elevation frequency histogram,and the local dense noise photons that thefirst-step cannot be identified are further eliminated.The following results are drawn:(1)experimental results on MATLAS with different topographies indicate that the average accuracy of second-step denoising exceeds 0.94,and the accuracy is effectively improves with the number of denoising times;(2)experiments on ICESat-2 under different observation conditions demonstrate that the algorithm can accurately identify signal photons in different surface types and topographies.Overall,the proposed algorithm has good adaptability and robustness for adaptive denoising of large-scale photons,and the denoising results can provide more reasonable and reliable data for sustainable urban development.展开更多
基金funded by the Technology Funding Scheme of China Construction Second Engineering Bureau LTD(2020ZX150002)the National Natural Science Foundation Project of China(12262018).
文摘To address the challenges posed by tunnel construction in the alpine region,silica fume mixed concrete is commonly used as a construction material.The correlation between silica fume content and the lining life requires immediate investigation.In view of this phenomenon,the durability of unit lining concrete is predicted by analyzing three key indicators:carbonation depth,relative dynamic elastic modulus,and residual quality.This prediction is achieved by integrating the Entropy Weight Method,Grey theory life prediction model and BP artificial neural networks using data from tests and predictions of these indicators.Then,the Entropy Weight-Grey theory-BP Network Model is compared with other methods to analyze the predicted life.Finally,verify the sci-entificity of this model,and the optimum silica fume content of unit concrete lining is verified.The results showed,1)The addition of silica fume will accelerate the carbonization of unit concrete lining,and slow down the freeze-thaw cycle and sulfate erosion.2)The utilization of artificial neural networks is essential for enhancing the realism of the data,as it emphasizes the significance of silica fume content.3)Silica fume content of 10%results in the longest life and is the most suitable for lining construction.4)A comparison between single-factor and multi-factor predictions indicates that the multi-factor approach yields a longer maximum life.This improvement can be attributed to the inclusion of additional factors,such as freeze-thaw cycles and carbonation,which enhance the predicted life when employing these methods.In conclusion,the Entropy Weight-Grey Theory-BP Network life prediction Model is well-suited for tunnel lining in the alpine sulfate area of northwest China.
基金the financial support received from the UK Engineering and Physical Sciences Research Council(EPSRC)through project grants EP/W010089/1 and EP/T005254/1.
文摘With the generation of both localised thermal and vibration in incremental sheet forming(ISF)by novel tool designs,rotational vibration assisted ISF(RV-ISF)can achieve significant force reduction and material softening.However,the combined thermal and vibration softening in RV-ISF is unclear.By evaluating the similarities and differences of friction stir ISF(FS-ISF)and RV-ISF,this study develops a novel approach to decouple and quantify the thermal and vibration softening effects in RV-ISF of AZ31B-H24,providing new insights into underlying thermal and vibration softening mechanism.Experimental results reveal that in RV-ISF of AZ31B-H24 the thermal softening due to frictional heating dominates with 45∼65%of softening,while the vibration effect only contributes up to 15%of softening,from the conventional ISF,depending on the tool designs and tool rotational speed.The double-offset tool(T2)produces greater vibration softening than the three-groove tool(T3)owing to the higher vibration amplitude of the T2 tool.An increase in tool rotational speed primarily enhances thermal softening with only marginal changes to the vibration effect.Microstructural analysis suggests that with average grain size of 0.94μm at the top layer,RV-ISF with T3 and 3000 rpm is more effective for microstructure refinement than that by FS-ISF,especially on the tool-sheet contact surface,which confirms the occurrence of surface shearing.This refinement is a result of the reduced recrystallisation degree,71.8%at the top bottom layer.Compared with FS-ISF,RV-ISF can lead to not only higher geometrically necessary dislocation density,but also higher fraction of low-angle grain boundaries,indicating that softening mechanism due to localised vibration effect is resulted from the enhanced rearrangement and annihilation of dislocations.These findings contribute to new understanding of the thermal and vibration softening effects in RV-ISF of AZ31B-H24 and offer a theoretical foundation for the tool design and process optimisation.
基金supported by the National Natural Science Foundation of China(No.24A20592).
文摘The Cambrian Qiongzhusi Formation in the Sichuan Basin harbors significant potential for shale gas harvesting.However,systematic disparities in mineral composition and reservoir architecture have been observed between intra-and extra-trough reservoirs within the Deyang-Anyue Rift Trough.These variations were primarily determined by divergences in the sedimentary environments developed during the evolution of the rift trough,which were a main factor in fostering the heterogeneous distribution of shale gas enrichment found today.However,the genetic mechanisms that govern reservoir heterogeneity across distinct structural domains(intra-trough,trough margin,and extra-trough)remain poorly understood,particularly regarding the coupling relationships between depositional environments,reservoir characteristics,and gas-bearing properties.This study adopts a multidisciplinary approach to investigating this issue that integrates core analysis,well-log interpretations,and geochemical data.Through systematic comparisons conducted using X-ray diffraction mineralogy,organic carbon quantification,and spontaneous imbibition experiments,we characterize the mineral assemblages,organic geochemical signatures,and pore structures found across the three structural domains of the Deyang-Anyue Rift Trough.The key findings are as follows:(1)The depositional environment is the main influence on reservoir distribution and organic matter enrichment,with intra-trough shales exhibiting a higher abundance of organic matter than their trough-margin and extra-trough counterparts.(2)Enhanced brittleness in intra-trough zones correlates with the predominance of biogenic silica therein.(3)Synergistic organic-inorganic interactions govern pore system development.(4)Gas-bearing capacity is jointly determined by effective porosity and organic matter content.These findings establish the rift trough as a preferential exploration target,providing critical geological guidance for optimizing shale gas exploration strategies in the Cambrian Qiongzhusi Formation.
基金Supported by National NaturalScience Foundation of China, No.81573239.
文摘The prevalence of colorectal cancer (CRC) and type 2 diabetes mellitus (T2DM) isincreasing globally. It is rarely noticed that the incidence of CRC is higher inpatients with T2DM. What needs to be mentioned is that metformin, a commonlyused clinical drug for T2DM, attracts scholars’ attention because of its benefits inlowering the risk of developing CRC. Hence, we try to find the common groundsof initiation of T2DM and CRC and the reason why metformin reduces the risk ofCRC in patients with T2DM. We noticed consistent changes of gut microbiota,such as elevated Bacteroides, Prevotella and Bifidobacterium and depressedFirmicutes and Lactobacillus. Furthermore, many studies in recent years haveproved that the efficacy of metformin, such as improving blood glucose, dependson the gut microbiota. Coincidentally, the progression of CRC is inseparable fromthe contributions of gut microbiota. Therefore, we first proposed the concept ofthe metformin-gut microbiota–CRC (in T2DM) axis to explain the effect ofmetformin in reducing CRC in patients with T2DM. In this review, we elaboratedthe new concept and its potential clinical application value.
基金supported financially by National Natural Science Foundation of China(Nos.81422046 and 31300293)the National Science and Technology Support Program of China(No.2013BAI11B02)+1 种基金the Natural Science Foundation of Yunnan Province(No.2012FB178)the project sponsored by SRF for ROCS,SEM to W.L.Xiao
文摘Phytochemical investigation of the aerial parts of Leonurus japonicus led to the isolation of one new labdane diterpenoid, leojaponin D （1） and two new ionone derivatives, leojaponones A and B （2 and 3）, together with seven known diterpenoids （4-10）. Their structures were elucidated by extensive 1D and 2D NMR spectroscopic data and by comparison with data reported in the literature. Selected isolates were evaluated their effects on lurkat IL2 secretino.
文摘Objective: Meta-analysis was conducted to assess whether combination of traditional Chinese and western medicine could enhance clinical outcomes compared to single western medicine in the treatment of acute pancreatitis (AP). Methods: This systematic review will include prospective and retrospective comparative studies in all languages and evaluate the clinical efficacy of integrated traditional Chinese and western medicine versus single western medicine in treatment AP. Animal studies will not be considered. Published articles were acquired from Jan. 2001 to Dec. 2017 by a comprehensive search in Chinese National Knowledge Infrastructure database (CNKI), Chinese WANFANG database. Exclusion criteria were non-comparative studies, hybrid treatment. The main points include clinical efficacy;carefully evaluating and reviewing the literature and filtering the literature according to inclusion criteria and exclusion criteria. Statistical analyses were performed using software Review Manager (Version 5.0). Publication biases of main results were examined by Stata 12.0. Results: 1262 cases of 1342 cases were effective and the effective rate reaches 94.04% in the group of integrated traditional Chinese and western medicine, while 949 cases of 1223 cases were effective and its effective rate can be up to 77.60% in the group of single western medicine (P > 0.05%, I2 = 0%, Odds Ratio (OR) = 4.98, 95% CI = 3. 79 - 6.54, P Conclusion: These results suggest that the therapeutic effects of integrated traditional Chinese and Western medicine on AP are better in treatment of AP than that of western medicine alone.
基金the fnancial support by the Major Research Plan Integration Project of the National Natural Science Foundation of China under Grant No.91215301by the National Basic Research Program of China under Grant No.2011CB013601
文摘Based on the asymmetric characteristic of skeleton curve obtained from dynamic tests on soils,a function with double asymptotes is proposed for describing the dynamic constitutive relations of soils.The hysteresis loops observed during unloading and reloading show the same form as the skeleton curve and are constructed by taking the ultimate stress as the corresponding asymptote.The coeffcient of initial unloading modulus is used to ensure that the constructed hysteresis loop fts well with the experimental data.Then,a new dynamic constitutive model considering the asymmetry of skeleton curve is elaborated.The verifcation tests on saturated Nanjing fne sand are performed using a hollow cylinder apparatus to verify the applicability of the UD model.It is found that the predicted curves by the UD model agree well with the test data.
基金Supported by the 2020 National Natural Science Foundation Cultivation Project of Guizhou Medical University Affiliated Hospital,No.gyfynsfc[2020]-14.
文摘BACKGROUND Eosinophilic granulomatosis with polyangiitis(EGPA),formerly known as Churg-Strauss syndrome,is a rare form of anti-neutrophil cytoplasmic antibodyassociated vasculitis characterized by asthma,vasculitis,and eosinophilia.CASE SUMMARY We report an atypical case of EGPA in a 20-year-old female patient.Unlike previously reported cases of EGPA,this patient’s initial symptom was asthma associated with a respiratory infection.This was followed by Loeffler endocarditis and cardiac insufficiency.She received treatment with methylprednisolone sodium succinate,low molecular weight heparin,recombinant human brain natriuretic peptide,furosemide,cefoperazone sodium/sulbactam sodium,and acyclovir.Despite prophylactic anticoagulation,she developed a large right ventricular thrombus.EGPA diagnosis was confirmed based on ancillary test results and specialty consultations.Subsequent treatment included mycophenolate mofetil.Her overall condition improved significantly after treatment,as evidenced by decreased peripheral blood eosinophils and cardiac markers.She was discharged after 17 d.Her most recent follow-up showed normal peripheral blood eosinophil levels,restored cardiac function,and a reduced cardiac mural thrombus size.CONCLUSION This case illustrates the swift progression of EGPA and underscores the significance of early detection and immediate intervention to ensure a favorable prognosis.
基金National Natural Science Foundation of China(NSFC)(61705044)One-Hundred Young Talents Program of Guangdong University of Technology(GDUT)(220413145)+1 种基金Research Grants Council,University Grants Committee(RGC,UGC)(GRF 152109/16E Poly U B-Q52T)Hong Kong Polytechnic University(Poly U)(G-YBVG)
文摘The novel vertically standing Pt Se2 film on transparent quartz was prepared by selenization of platinum film deposited by the magnetron sputtering method, and an Nd:Lu VO4 passively mode-locked solid-state laser was realized by using the fabricated Pt Se2 film as a saturable absorber. The X-ray diffraction pattern and Raman spectrum of the film indicate its good crystallinity with a layered structure. The thickness of Pt Se2 film is measured to be 24 nm according to the cross-section height profile of the atomic force microscope image. Highresolution transmission electron microscopy images clearly demonstrate its vertically standing structure with an interlayer distance of 0.54 nm along the c-axis direction. The modulation depth(ΔT) and saturation fluence(Φs)of Pt Se2 film are measured to be 12.6% and 17.1 μJ∕cm2, respectively. The obtained mode-locked laser spectrum has a central wavelength of 1066.573 nm, with a 3 d B bandwidth of 0.106 nm. The transform limited pulse width of the mode-locked laser was calculated to be 15.8 ps. A maximum average output power of 180 m W with a working repetition rate of 61.3 MHz is obtained. To the best of our knowledge, this is the first report of the generation of ultrafast mode-locked laser pulses by using layered Pt Se2 as a saturable absorber.
基金We are grateful for the funding provided by grants from the National Natural Science Foundation of China(NSFC)projects(Grant nos.81972687,82073064,and 81874167).
文摘Dear Editor,There is a growing body of evidence that the human rhomboid family-1 gene(RHBDF1)plays an important role in the modulation of tumor inflammatory(Supplementary Fig.la)and hypoxic microenvironment.
基金supported by the National Key R&D Program of China under[grant number 2021YFF0704600]the National Natural Science Foundation of China under[grant number 42171352,42271365,U22A20566]the High-Level Talent Aggregation Project in Hunan Province,China-Innovation Team under[grant number 2019RS1060].
文摘Spaceborne photon-counting LiDAR is significantly affected by noise,and existing denoising algorithms cannot be universally adapted to different surface types and topographies under all observation conditions.Accordingly,a new denoising method is presented to extract signal photons adaptively.The method includes two steps.First,the local neighborhood radius is calculated according to photons’density,then thefirst-step denoising process is completed via photons’curvature feature based on KNN search and covariance matrix.Second,the local photonfiltering direction and threshold are obtained based on thefirst-step denoising results by RANSAC and elevation frequency histogram,and the local dense noise photons that thefirst-step cannot be identified are further eliminated.The following results are drawn:(1)experimental results on MATLAS with different topographies indicate that the average accuracy of second-step denoising exceeds 0.94,and the accuracy is effectively improves with the number of denoising times;(2)experiments on ICESat-2 under different observation conditions demonstrate that the algorithm can accurately identify signal photons in different surface types and topographies.Overall,the proposed algorithm has good adaptability and robustness for adaptive denoising of large-scale photons,and the denoising results can provide more reasonable and reliable data for sustainable urban development.
