BACKGROUND Immune checkpoint inhibitors(ICIs)have revolutionized cancer therapy but are associated with immune-related adverse events,including ICIs hepatitis.Mycophenolate mofetil(MMF)is often used as a second-line i...BACKGROUND Immune checkpoint inhibitors(ICIs)have revolutionized cancer therapy but are associated with immune-related adverse events,including ICIs hepatitis.Mycophenolate mofetil(MMF)is often used as a second-line immunosuppressive agent for steroid-refractory cases.However,there is no standardized approach to MMF tapering,leading to uncertainties regarding relapse risk,optimal tapering strategies,and long-term outcomes.AIM To evaluate current evidence on MMF tapering in ICI hepatitis,focusing on strategies,clinical outcomes,and the risk of hepatitis recurrence.Additionally,we explore the feasibility of reintroducing ICI therapy after immunosuppression withdrawal.METHODS A comprehensive literature search was conducted in PubMed,EMBASE,and clinical trial registries to identify studies reporting MMF use and tapering strategies in ICI hepatitis.We extracted data from manuscripts including patient characteristics,MMF dosing regimens,tapering duration,relapse rates,and oncologic outcomes.Risk factors for recurrence and successful tapering were analyzed.RESULTS There was significant heterogeneity in the duration of MMF taper,which ranged from 4 weeks to greater than 6 months.The tapering schedules presented were individualized based on the severity of liver injury,patient response to treatment,and risk factors for relapse.We summarize current tapering approaches,including rapid vs slow withdrawal,predictors of successful tapering,and alternative immunosuppressive strategies.The impact of MMF duration on liver recovery,relapse risk,and cancer prognosis will be discussed.Evidence on ICI rechallenge post-taper will also be reviewed.CONCLUSION While MMF is effective in managing ICI hepatitis,tapering remains a clinical challenge with potential risks of hepatitis flare and disease progression.Standardized tapering protocols are needed to optimize immunosuppression while preserving anticancer efficacy.Future studies should focus on biomarker-driven tapering strategies and prospective trials to establish best practices.展开更多
On the basis of crystallographic characteristics of ADP (ammonium dihydrogen phosphate) crystals and the selected growth conditions, the growth habit of ADP crystals was studied. In comparison with pyramidal planes, t...On the basis of crystallographic characteristics of ADP (ammonium dihydrogen phosphate) crystals and the selected growth conditions, the growth habit of ADP crystals was studied. In comparison with pyramidal planes, the growth rate of prismatic faces is slower and more sensitive to the additives and impurities for ADP crystals. When the supersaturation is low, the advance of growth steps on prismatic face can be blocked by ethanol or impurities, the crystal morphology is changed from the tetragonal prism to shuttle (i.e., the tapered shape). The tapering formation of ADP crystallites was structurally studied in a novel view.展开更多
We propose and experimentally demonstrate a broadband 1 × 3 adiabatic splitter based on the silicon-on-insulator technology, with simultaneous tapering of velocity and coupling. The designed structure becomes sim...We propose and experimentally demonstrate a broadband 1 × 3 adiabatic splitter based on the silicon-on-insulator technology, with simultaneous tapering of velocity and coupling. The designed structure becomes simulated transmission uniformity of three outputs better than 0.5dB in a broadband of 250nm, and a large simulated fabrication tolerance is obtained. A manufactured splitter whose parameters greatly diverge from the design acquires a measured result of the worst splitting ratio better than 1.5dB as well as an excess loss lower than 0.8 dB in a large wavelength range of 80nm. A post-simulation based on the tested splitter obtains a result that meets the actual transmission well.展开更多
The performance of the optical fiber coupler prepared with fused biconical taper method is determined by the quality of fused stretching. Besides, the stable high-temperature heat source is the essential guarantee for...The performance of the optical fiber coupler prepared with fused biconical taper method is determined by the quality of fused stretching. Besides, the stable high-temperature heat source is the essential guarantee for fused stretching process to go smoothly. The way of using AC （alternating current） arc as the heat source is proposed in this article. In addition, the paper also introduces high-frequency high-voltage power supply with the characteristics of constant current and restricted voltage, which is composed of preceding voltage regulation part and following inverter.展开更多
Rheumatoid arthritis(RA),as a chronic autoimmune disease,significantly impairs patients'quality of life.(1)Glucocorticoids(GC)remain crucial in RA management even in the biologics era,owing to their potent anti-in...Rheumatoid arthritis(RA),as a chronic autoimmune disease,significantly impairs patients'quality of life.(1)Glucocorticoids(GC)remain crucial in RA management even in the biologics era,owing to their potent anti-inflammatory and immunosuppressive properties.However,prolonged GC use carries significant safety risks,including infections,osteoporosis,and cardiovascular complications.Therefore,clinical guidelines advocate minimizing both the dose and duration of GC therapy.展开更多
We have demonstrated the highly efficient excitation of the linearly polarized mode(LP01)in ring-core fibers(RCFs)by tapering the spliced point between the RCF and the standard single-mode fiber(SMF)to optimize all-fi...We have demonstrated the highly efficient excitation of the linearly polarized mode(LP01)in ring-core fibers(RCFs)by tapering the spliced point between the RCF and the standard single-mode fiber(SMF)to optimize all-fiber orbital angular momentum(OAM)generation.The tapering technique has been investigated theoretically and experimentally.Before tapering,only 50%of light can be coupled from SMFs to RCFs.The modal interference spectrum with an extinction ratio(ER)of～9 dB is observed,showing that higher-order modes are excited in RCF.By tapering the spliced point,90%of light is coupled,and the ER is minimized to be～2 dB,indicating that the higher-order modes are effectively suppressed by tapering.Such tapered spliced points of RCF–SMF are further applied for all-fiber OAM generation.The efficiencies of OAM+1 and OAM?1 generation are found to be enhanced by approximately 11.66%and 12.41%,respectively,showing that the tapered spliced point of the RCF–SMF is a feasible way to optimize OAM generation.展开更多
Optical fibres with diameters at micro-or sub-micrometre scale are widely adopted as a convenient tool for studying light–matter interactions.To prepare such devices,two elements are indispensable:a heat source and a...Optical fibres with diameters at micro-or sub-micrometre scale are widely adopted as a convenient tool for studying light–matter interactions.To prepare such devices,two elements are indispensable:a heat source and a pulling force.In this paper,we report a novel fibre-tapering technique in which micro-sized plasmonic heaters and elaborately deformed optical fibres are compactly combined,free of flame and bulky pulling elements.Using this technique,micro-nano fibres with abrupt taper and ultra-short transition regions were successfully fabricated,which would otherwise be a challenge for traditional techniques.The compactness of the proposed system enabled it to be further transferred to a scanning electron microscope for in-situ monitoring of the tapering process.The essential dynamics of“heat and pull”was directly visualised with nanometre precision in real time and theoretically interpreted,thereby establishing an example for future in-situ observations of micro and nanoscale light-matter interactions.展开更多
A modal interferometer is experimentally demonstrated based on tapering a single-mode-multimode-single- mode （SMS） fiber structure heated by hydrogen flame. The interference fringe begins to form when tapering lengt...A modal interferometer is experimentally demonstrated based on tapering a single-mode-multimode-single- mode （SMS） fiber structure heated by hydrogen flame. The interference fringe begins to form when tapering length is 19.8 mm, and becomes regular and clear when the tapering length is longer and the tapered waist diameter is smaller. Annealing process is undertaken to achieve a high extension ratio of approximately 17 dB with free spectral range of 1.5 nm when the tapering length is 33 mm and the tapered waist diameter is approximately 5 μm. The temperature and axial strain dependences of the tapered SMS structure are characterized, and the measured temperature and strain coefficients are ＋7 pm/℃ and -9.536 pm/με, respectively.展开更多
One of the main issues in designing optimum tapered cascades for uranium enrichment for annual fuel production in a power reactor is whether to employ large(fat)or small(thin)cascades.What will be the permissible and ...One of the main issues in designing optimum tapered cascades for uranium enrichment for annual fuel production in a power reactor is whether to employ large(fat)or small(thin)cascades.What will be the permissible and optimal ranges of the number of machines that can be used in a cascade?For the first time,the permissible and optimal ranges of the number of gas centrifuges that can be utilized in a cascade were investigated using two types of centrifuges,and the performance of small and large tapered cascades was discussed.The particle swarm optimization algorithm(PSO)has been used to optimize tapered cascades.The results show:(1)For the first centrifuge,41 cascades(91≤n≤4897)and for the second centrifuge,49 cascades(18≤n≤3839)with small and large sizes can be used in enrichment facilities,and the best cascade for them has 530(with 23 stages)and 39(with 7 stages)centrifuges,respectively.(2)For both centrifuges,when 600≤n(number of centrifuges=n),the large cascade performance changes are relatively insignificant.(3)For both types of gas centrifuges,the annual los s of separation power in enrichment facilities is approximately 1.25%-4.82%of the total separation work required.展开更多
When making assessments of forest resources,there is nearly ubiquitous interest in quantifying current status and trends in tree biomass and carbon stocks.While important at various spatial scales,typical estimations ...When making assessments of forest resources,there is nearly ubiquitous interest in quantifying current status and trends in tree biomass and carbon stocks.While important at various spatial scales,typical estimations pertinent to broad forest management and policy issues are conducted for large areas such as state,regional,and national perspectives.These assessments are usually accomplished using large-area forest inventory data collected by National Forest Inventory(NFI)programs.While NFI efforts commonly collect size data for individual trees,there is often limited information for tree seedlings,e.g.,frequency by species.To fully describe the tree population across the entire range of sizes present,this study proposes methods to predict individual seedling groundline diameter and height using models developed from trees having a diameter at breast height(DBH)less than 7.62 cm.These attributes are subsequently used for the prediction of seedling stem volume,total aboveground biomass,and carbon content.The results suggest a smooth transition in tree attributes as size increases to where direct measurement of individual trees and prediction of their volume,biomass,and carbon are implemented as part of standard inventory protocols.Analyses including the full spectrum of tree sizes show that seedlings contribute roughly 0.6%–0.7%of the total tree volume/mass.This additional suite of information provides opportunities for more holistic assessments across the full spectrum of the tree resource or for specialized subdomains that include the seedling component.展开更多
In order to eliminate the meshing interference between the flexspline and circular spline after the taper deformation of the flexspline,the radial deformation difference method,major and minor axis fitting method,and ...In order to eliminate the meshing interference between the flexspline and circular spline after the taper deformation of the flexspline,the radial deformation difference method,major and minor axis fitting method,and ellipse fitting method are used to modify the tooth thickness of the flexspline and analyze the performance indexes such as the assembly stress,transmission error,and fatigue life.Firstly,the conjugate tooth profile is solved based on the quadruple-circular-arc tooth profile and modified kinematic method.Then,based on the finite element radial deformation of the flexspline,the principle and characteristics of three modification methods are analyzed,and the modification amount of each section of the flexspline tooth is calculated.Finally,the influence of the three modification methods on the performance of the harmonic drive is compared.The results show that the radial deformation difference method can initially determine the modification amount.The minimum static assembly stress is 406.22 MPa by the major and minor axis fitting method.The ellipse fitting method has the best dynamic performance,small transmission error fluctuation,a peak-to-peak value of 3.060",and a maximum fatigue life of 10^(7.558)cycles.展开更多
Fabrication of optical fiber tapers is realized with a combination of plasmonic microheaters and specially designed structural bending of optical fibers,which provide the necessary elements of"heat and pull"...Fabrication of optical fiber tapers is realized with a combination of plasmonic microheaters and specially designed structural bending of optical fibers,which provide the necessary elements of"heat and pull".The resultant compactness and flame-free condition enable monitoring of the tapering process inside a scanning electron microscope.展开更多
Spiral bevel gears are critical transmission components,and are widely used in the aerospace field.This paper proposes a new multi-DOF envelope forming process for fabricating spiral bevel gears.Firstly,the multi-DOF ...Spiral bevel gears are critical transmission components,and are widely used in the aerospace field.This paper proposes a new multi-DOF envelope forming process for fabricating spiral bevel gears.Firstly,the multi-DOF envelope forming principle of spiral bevel gears is proposed.Secondly,the design methods for the envelope tool geometry and movement are proposed based on the envelope geometry and movement relationships.Thirdly,the metal flow and tooth filling laws are revealed through 3D FE simulation of the multi-DOF envelope forming process of a typical spiral bevel gear.Fourthly,a new method for separating the envelope tool and the formed spiral bevel gear with back taper tooth is proposed to avoid their interference.Finally,experiments on multi-DOF envelope forming of this typical spiral bevel gear are conducted using new heavy load multi-DOF envelope forming equipment.The simulation and experimental results show the feasibility of the proposed multi-DOF envelope forming process for fabricating spiral bevel gears with back taper tooth and the corresponding process design methods.展开更多
In this study,we developed a single-beam optical trap-based surface-enhanced Raman scattering(SERS)optofluidic molecular fingerprint spectroscopy detection system.This system utilizes a single-beam optical trap to con...In this study,we developed a single-beam optical trap-based surface-enhanced Raman scattering(SERS)optofluidic molecular fingerprint spectroscopy detection system.This system utilizes a single-beam optical trap to concentrate free silver nanoparticles(AgNPs)within an optofluidic chip,significantly enhancing SERS performance.We investigated the optical field distribution characteristics within the tapered fiber using COMSOL simulation software and established a MATLAB simulation model to validate the single-beam optical trap's effectiveness in capturing AgNPs,demonstrating the theoretical feasibility of our approach.To verify the particle capture efficacy of the system,we experimentally controlled the optical trap's on-off state to manage the capture and release of particles precisely.The experimental results indicated that the Raman signal intensity in the capture state was significantly higher than in the non-capture state,confirming that the single-beam optical trap effectively enhances the SERS detection capability of the optofluidic detection system.Furthermore,we employed Raman mapping techniques to investigate the impact of the capture area on the SERS effect,revealing that the spectral intensity of molecular fingerprints in the laser-trapping region is significantly improved.We successfully detected the Raman spectrum of crystal violet at a concentration of 10^(−9)mol/L and pesticide thiram at a concentration of 10^(−5)mol/L,further demonstrating the ability of the single-beam optical trap in enhancing the molecular fingerprint spectrum identification capability of the SERS optofluidic chips.The optical trapping SERS optofluidic detection system developed in this study,as a key component of an integrated optoelectronic sensing system,holds the potential for integration with portable high-power lasers and high-performance Raman spectrometers.This integration is expected to advance highly integrated technologies and significantly enhance the overall performance and portability of optoelectronic sensing systems.展开更多
The travel time and amplitude of ground-penetrating radar （GPR） waves are closely related to medium parameters such as water content, porosity, and dielectric permittivity. However, conventional estimation methods, ...The travel time and amplitude of ground-penetrating radar （GPR） waves are closely related to medium parameters such as water content, porosity, and dielectric permittivity. However, conventional estimation methods, which are mostly based on wave velocity, are not suitable for real complex media because of limited resolution. Impedance inversion uses the reflection coefficient of radar waves to directly calculate GPR impedance and other parameters of subsurface media. We construct a 3D multiscale stochastic medium model and use the mixed Gaussian and exponential autocorrelation function to describe the distribution of parameters in real subsurface media. We introduce an elliptical Gaussian function to describe local random anomalies. The tapering function is also introduced to reduce calculation errors caused by the numerical simulation of discrete grids. We derive the impedance inversion workflow and test the calculation precision in complex media. Finally, we use impedance inversion to process GPR field data in a polluted site in Mongolia. The inversion results were constrained using borehole data and validated by resistivity data.展开更多
Stem volume estimation is crucial in forest ecology and management,particularly for timber harvesting strategies and carbon stock assessments.This study aimed to develop a variable-exponent taper equation specifically...Stem volume estimation is crucial in forest ecology and management,particularly for timber harvesting strategies and carbon stock assessments.This study aimed to develop a variable-exponent taper equation specifically tailored to savanna tree species using close-range photogrammetry(CRP)data and to evaluate its performance against conventional volume equations for stem volume estimation.A dataset of 30 trees across five dominant savanna species was used to fit the taper model,which was validated using a separate dataset of 322 trees from 14 species.The results demonstrated significant improvements in volume estimation accuracy when using the taper equation.At the tree level,the root mean square error(RMSE)decreased by 47%,from 598 to 319 dm^(3),and the mean absolute bias(MAB)by 48%,from 328 to 172 dm3,compared to volume equations.Similarly,at the plot level,RMSE was reduced by 42% and MAB by 40%.The model performed well for species with regular forms.However,species with irregular tapers exhibited higher errors,reflecting the challenges of modeling stem forms of mixed species.The use of CRP proved valuable,providing high-resolution diameter measurements that improved model parameterization.This study underscores the importance of advanced data collection methods for enhancing taper model accuracy and suggests that further species-specific adjustments are needed to improve performance for species with irregular forms.The findings support the broader application of taper equations for improving stem volume estimates in savanna ecosystems,contributing to better forest management and resource monitoring practices.展开更多
BACKGROUND Cardiac sarcoidosis(CS)is an infiltrative disease with manifestations such as nonsustained ventricular tachycardia(NSVT)and heart failure(HF).Antiphospholipid syndrome(APS)and antiphospholipid positivity(AP...BACKGROUND Cardiac sarcoidosis(CS)is an infiltrative disease with manifestations such as nonsustained ventricular tachycardia(NSVT)and heart failure(HF).Antiphospholipid syndrome(APS)and antiphospholipid positivity(APP)are prothrombotic phenomena which elevate risk for thromboembolism.CS with active systemic sarcoid and APS/APP is a rare combination of diseases.CASE SUMMARY A 54 year old male with HF presented with several cardiopulmonary symptoms.Chest imaging showed bilateral patchy and reticulonodular infiltrates.Subsequent lung biopsy confirmed pulmonary sarcoidosis.Positron emission tomography revealed active systemic sarcoidosis(SS)and fibrotic CS.Positive antiphospholipid antibodies without thromboembolism confirmed APP.HF and APP were managed with medical therapy.Fibrotic CS and NSVT required permanent cardiac device and antiarrhythmic therapy.SS was managed with early taper of steroids and transition to biologics.CONCLUSION Fibrotic CS with active SS and APS/APP has not been previously described in literature.This case utilized a modified approach for the management of this combination of diseases.As immunosuppressants such as steroids have limited utility in fibrotic sarcoidosis and a potential for thromboembolic complications in the presence of APP,an accelerated transition to non-thrombotic immunosuppressants can be advantageous in the long term treatment of this combination of diseases.展开更多
This paper presents a biosensor utilizing a whispering gallery mode(WGM)resonator characterized by azimuthal symmetry and crescent-shaped coatings of silver.The study investigates the impact of the coupling gap on the...This paper presents a biosensor utilizing a whispering gallery mode(WGM)resonator characterized by azimuthal symmetry and crescent-shaped coatings of silver.The study investigates the impact of the coupling gap on the extinction ratio and Q-factor of the setup.The resonator is coated with silver in crescent shapes,ranging from 40 nm to 65 nm in thickness.Coupling is achieved with a silica waveguide,simulating the tapered fiber coupling method.Notably,the resonator exhibits a maximum sensitivity of 220 nm/RIU when coated with 55-nm-thick silver in conjunction with a 4-nm-thick layer of thiol-tethered deoxyribonucleic acid(DNA).This biosensor holds promise for biomolecule detection applications.展开更多
Quantum photonic integrated circuits offer enhanced stability and scalability for quantum communications,sensing, and computing. Transverse modes in multimode waveguides enable high-dimensional scalability and versati...Quantum photonic integrated circuits offer enhanced stability and scalability for quantum communications,sensing, and computing. Transverse modes in multimode waveguides enable high-dimensional scalability and versatile photon manipulation, but practical adoption requires compact and fabrication-tolerant quantum interference devices. Here, we present an ultra-compact taper-stepped beamsplitter that enables quantum interference between photon pairs in different transverse modes, and cascade it to realize NOON state interferometry. We experimentally achieve high visibilities of 93.9% for HOM interference and 86.5% for NOON state interference,demonstrating that efficient mode interference with active tuning can be realized on this platform.展开更多
文摘BACKGROUND Immune checkpoint inhibitors(ICIs)have revolutionized cancer therapy but are associated with immune-related adverse events,including ICIs hepatitis.Mycophenolate mofetil(MMF)is often used as a second-line immunosuppressive agent for steroid-refractory cases.However,there is no standardized approach to MMF tapering,leading to uncertainties regarding relapse risk,optimal tapering strategies,and long-term outcomes.AIM To evaluate current evidence on MMF tapering in ICI hepatitis,focusing on strategies,clinical outcomes,and the risk of hepatitis recurrence.Additionally,we explore the feasibility of reintroducing ICI therapy after immunosuppression withdrawal.METHODS A comprehensive literature search was conducted in PubMed,EMBASE,and clinical trial registries to identify studies reporting MMF use and tapering strategies in ICI hepatitis.We extracted data from manuscripts including patient characteristics,MMF dosing regimens,tapering duration,relapse rates,and oncologic outcomes.Risk factors for recurrence and successful tapering were analyzed.RESULTS There was significant heterogeneity in the duration of MMF taper,which ranged from 4 weeks to greater than 6 months.The tapering schedules presented were individualized based on the severity of liver injury,patient response to treatment,and risk factors for relapse.We summarize current tapering approaches,including rapid vs slow withdrawal,predictors of successful tapering,and alternative immunosuppressive strategies.The impact of MMF duration on liver recovery,relapse risk,and cancer prognosis will be discussed.Evidence on ICI rechallenge post-taper will also be reviewed.CONCLUSION While MMF is effective in managing ICI hepatitis,tapering remains a clinical challenge with potential risks of hepatitis flare and disease progression.Standardized tapering protocols are needed to optimize immunosuppression while preserving anticancer efficacy.Future studies should focus on biomarker-driven tapering strategies and prospective trials to establish best practices.
基金Project supported by the National Natural Science Foundation of China (20471012), the Foundation for the Author of National Excellent Doctoral Dissertation of China (200322), the Research Fund for the Doctoral Program of Higher Education (20040141004) and the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry
文摘On the basis of crystallographic characteristics of ADP (ammonium dihydrogen phosphate) crystals and the selected growth conditions, the growth habit of ADP crystals was studied. In comparison with pyramidal planes, the growth rate of prismatic faces is slower and more sensitive to the additives and impurities for ADP crystals. When the supersaturation is low, the advance of growth steps on prismatic face can be blocked by ethanol or impurities, the crystal morphology is changed from the tetragonal prism to shuttle (i.e., the tapered shape). The tapering formation of ADP crystallites was structurally studied in a novel view.
基金Supported by the National High-Technology Research and Development Program of China under Grant Nos 2015AA016904and 2013AA014402the National Basic Research Program of China under Grant No 2011CB301701the National Natural Science Foundation of China under Grant No 61275065
文摘We propose and experimentally demonstrate a broadband 1 × 3 adiabatic splitter based on the silicon-on-insulator technology, with simultaneous tapering of velocity and coupling. The designed structure becomes simulated transmission uniformity of three outputs better than 0.5dB in a broadband of 250nm, and a large simulated fabrication tolerance is obtained. A manufactured splitter whose parameters greatly diverge from the design acquires a measured result of the worst splitting ratio better than 1.5dB as well as an excess loss lower than 0.8 dB in a large wavelength range of 80nm. A post-simulation based on the tested splitter obtains a result that meets the actual transmission well.
文摘The performance of the optical fiber coupler prepared with fused biconical taper method is determined by the quality of fused stretching. Besides, the stable high-temperature heat source is the essential guarantee for fused stretching process to go smoothly. The way of using AC （alternating current） arc as the heat source is proposed in this article. In addition, the paper also introduces high-frequency high-voltage power supply with the characteristics of constant current and restricted voltage, which is composed of preceding voltage regulation part and following inverter.
文摘Rheumatoid arthritis(RA),as a chronic autoimmune disease,significantly impairs patients'quality of life.(1)Glucocorticoids(GC)remain crucial in RA management even in the biologics era,owing to their potent anti-inflammatory and immunosuppressive properties.However,prolonged GC use carries significant safety risks,including infections,osteoporosis,and cardiovascular complications.Therefore,clinical guidelines advocate minimizing both the dose and duration of GC therapy.
基金supported by the National Natural Science Foundation of China(Nos.61635006,61975108,and 61605108)the Shuguang Program(No.16SG35).
文摘We have demonstrated the highly efficient excitation of the linearly polarized mode(LP01)in ring-core fibers(RCFs)by tapering the spliced point between the RCF and the standard single-mode fiber(SMF)to optimize all-fiber orbital angular momentum(OAM)generation.The tapering technique has been investigated theoretically and experimentally.Before tapering,only 50%of light can be coupled from SMFs to RCFs.The modal interference spectrum with an extinction ratio(ER)of～9 dB is observed,showing that higher-order modes are excited in RCF.By tapering the spliced point,90%of light is coupled,and the ER is minimized to be～2 dB,indicating that the higher-order modes are effectively suppressed by tapering.Such tapered spliced points of RCF–SMF are further applied for all-fiber OAM generation.The efficiencies of OAM+1 and OAM?1 generation are found to be enhanced by approximately 11.66%and 12.41%,respectively,showing that the tapered spliced point of the RCF–SMF is a feasible way to optimize OAM generation.
基金supported by the National Natural Science Foundation of China(Grant Nos.61927820,61905201,and 62275221).
文摘Optical fibres with diameters at micro-or sub-micrometre scale are widely adopted as a convenient tool for studying light–matter interactions.To prepare such devices,two elements are indispensable:a heat source and a pulling force.In this paper,we report a novel fibre-tapering technique in which micro-sized plasmonic heaters and elaborately deformed optical fibres are compactly combined,free of flame and bulky pulling elements.Using this technique,micro-nano fibres with abrupt taper and ultra-short transition regions were successfully fabricated,which would otherwise be a challenge for traditional techniques.The compactness of the proposed system enabled it to be further transferred to a scanning electron microscope for in-situ monitoring of the tapering process.The essential dynamics of“heat and pull”was directly visualised with nanometre precision in real time and theoretically interpreted,thereby establishing an example for future in-situ observations of micro and nanoscale light-matter interactions.
基金supported in part by the National "973" Program of China(No.2011CB301700)the National Natural Science Foundation of China(Nos.61007052, 61071011,61107041,61127016)+3 种基金the International Cooperation Project from the Ministry of Science and Technology of China(No.2011FDA11780)the STCSM Project(Nos.09JC1408100,10DJ1400402)the "SMC Young Star" Scientist Program of Shanghai Jiao Tong Universitythe National Key Lab Projects(No. GKZD030021)
文摘A modal interferometer is experimentally demonstrated based on tapering a single-mode-multimode-single- mode （SMS） fiber structure heated by hydrogen flame. The interference fringe begins to form when tapering length is 19.8 mm, and becomes regular and clear when the tapering length is longer and the tapered waist diameter is smaller. Annealing process is undertaken to achieve a high extension ratio of approximately 17 dB with free spectral range of 1.5 nm when the tapering length is 33 mm and the tapered waist diameter is approximately 5 μm. The temperature and axial strain dependences of the tapered SMS structure are characterized, and the measured temperature and strain coefficients are ＋7 pm/℃ and -9.536 pm/με, respectively.
文摘One of the main issues in designing optimum tapered cascades for uranium enrichment for annual fuel production in a power reactor is whether to employ large(fat)or small(thin)cascades.What will be the permissible and optimal ranges of the number of machines that can be used in a cascade?For the first time,the permissible and optimal ranges of the number of gas centrifuges that can be utilized in a cascade were investigated using two types of centrifuges,and the performance of small and large tapered cascades was discussed.The particle swarm optimization algorithm(PSO)has been used to optimize tapered cascades.The results show:(1)For the first centrifuge,41 cascades(91≤n≤4897)and for the second centrifuge,49 cascades(18≤n≤3839)with small and large sizes can be used in enrichment facilities,and the best cascade for them has 530(with 23 stages)and 39(with 7 stages)centrifuges,respectively.(2)For both centrifuges,when 600≤n(number of centrifuges=n),the large cascade performance changes are relatively insignificant.(3)For both types of gas centrifuges,the annual los s of separation power in enrichment facilities is approximately 1.25%-4.82%of the total separation work required.
文摘When making assessments of forest resources,there is nearly ubiquitous interest in quantifying current status and trends in tree biomass and carbon stocks.While important at various spatial scales,typical estimations pertinent to broad forest management and policy issues are conducted for large areas such as state,regional,and national perspectives.These assessments are usually accomplished using large-area forest inventory data collected by National Forest Inventory(NFI)programs.While NFI efforts commonly collect size data for individual trees,there is often limited information for tree seedlings,e.g.,frequency by species.To fully describe the tree population across the entire range of sizes present,this study proposes methods to predict individual seedling groundline diameter and height using models developed from trees having a diameter at breast height(DBH)less than 7.62 cm.These attributes are subsequently used for the prediction of seedling stem volume,total aboveground biomass,and carbon content.The results suggest a smooth transition in tree attributes as size increases to where direct measurement of individual trees and prediction of their volume,biomass,and carbon are implemented as part of standard inventory protocols.Analyses including the full spectrum of tree sizes show that seedlings contribute roughly 0.6%–0.7%of the total tree volume/mass.This additional suite of information provides opportunities for more holistic assessments across the full spectrum of the tree resource or for specialized subdomains that include the seedling component.
文摘In order to eliminate the meshing interference between the flexspline and circular spline after the taper deformation of the flexspline,the radial deformation difference method,major and minor axis fitting method,and ellipse fitting method are used to modify the tooth thickness of the flexspline and analyze the performance indexes such as the assembly stress,transmission error,and fatigue life.Firstly,the conjugate tooth profile is solved based on the quadruple-circular-arc tooth profile and modified kinematic method.Then,based on the finite element radial deformation of the flexspline,the principle and characteristics of three modification methods are analyzed,and the modification amount of each section of the flexspline tooth is calculated.Finally,the influence of the three modification methods on the performance of the harmonic drive is compared.The results show that the radial deformation difference method can initially determine the modification amount.The minimum static assembly stress is 406.22 MPa by the major and minor axis fitting method.The ellipse fitting method has the best dynamic performance,small transmission error fluctuation,a peak-to-peak value of 3.060",and a maximum fatigue life of 10^(7.558)cycles.
文摘Fabrication of optical fiber tapers is realized with a combination of plasmonic microheaters and specially designed structural bending of optical fibers,which provide the necessary elements of"heat and pull".The resultant compactness and flame-free condition enable monitoring of the tapering process inside a scanning electron microscope.
基金the National Science and Technology Major Project of China(No.2019-VII0017e0158)the National Natural Science Foundation of China(No.U21A20131)+1 种基金the Industry-University Research Cooperation Project,China(No.HFZL2020CXY025)the National Key Laboratory of Science and Technology on Helicopter Transmission,China(No.HTL-O-21G05).
文摘Spiral bevel gears are critical transmission components,and are widely used in the aerospace field.This paper proposes a new multi-DOF envelope forming process for fabricating spiral bevel gears.Firstly,the multi-DOF envelope forming principle of spiral bevel gears is proposed.Secondly,the design methods for the envelope tool geometry and movement are proposed based on the envelope geometry and movement relationships.Thirdly,the metal flow and tooth filling laws are revealed through 3D FE simulation of the multi-DOF envelope forming process of a typical spiral bevel gear.Fourthly,a new method for separating the envelope tool and the formed spiral bevel gear with back taper tooth is proposed to avoid their interference.Finally,experiments on multi-DOF envelope forming of this typical spiral bevel gear are conducted using new heavy load multi-DOF envelope forming equipment.The simulation and experimental results show the feasibility of the proposed multi-DOF envelope forming process for fabricating spiral bevel gears with back taper tooth and the corresponding process design methods.
基金financial supports from National Natural Science Foundation of China(62175023).
文摘In this study,we developed a single-beam optical trap-based surface-enhanced Raman scattering(SERS)optofluidic molecular fingerprint spectroscopy detection system.This system utilizes a single-beam optical trap to concentrate free silver nanoparticles(AgNPs)within an optofluidic chip,significantly enhancing SERS performance.We investigated the optical field distribution characteristics within the tapered fiber using COMSOL simulation software and established a MATLAB simulation model to validate the single-beam optical trap's effectiveness in capturing AgNPs,demonstrating the theoretical feasibility of our approach.To verify the particle capture efficacy of the system,we experimentally controlled the optical trap's on-off state to manage the capture and release of particles precisely.The experimental results indicated that the Raman signal intensity in the capture state was significantly higher than in the non-capture state,confirming that the single-beam optical trap effectively enhances the SERS detection capability of the optofluidic detection system.Furthermore,we employed Raman mapping techniques to investigate the impact of the capture area on the SERS effect,revealing that the spectral intensity of molecular fingerprints in the laser-trapping region is significantly improved.We successfully detected the Raman spectrum of crystal violet at a concentration of 10^(−9)mol/L and pesticide thiram at a concentration of 10^(−5)mol/L,further demonstrating the ability of the single-beam optical trap in enhancing the molecular fingerprint spectrum identification capability of the SERS optofluidic chips.The optical trapping SERS optofluidic detection system developed in this study,as a key component of an integrated optoelectronic sensing system,holds the potential for integration with portable high-power lasers and high-performance Raman spectrometers.This integration is expected to advance highly integrated technologies and significantly enhance the overall performance and portability of optoelectronic sensing systems.
基金supported by the Doctoral Fund Project of the Ministry of Education(No.20130061110060 class tutors)the Post-Doctoral Fund Project(No.2015M571366)+1 种基金the National Natural Science Foundation of China(No.41174097)US DoD ARO Project"Advanced Mathematical Algorithm"(No.W911NF-11-2-0046)
文摘The travel time and amplitude of ground-penetrating radar （GPR） waves are closely related to medium parameters such as water content, porosity, and dielectric permittivity. However, conventional estimation methods, which are mostly based on wave velocity, are not suitable for real complex media because of limited resolution. Impedance inversion uses the reflection coefficient of radar waves to directly calculate GPR impedance and other parameters of subsurface media. We construct a 3D multiscale stochastic medium model and use the mixed Gaussian and exponential autocorrelation function to describe the distribution of parameters in real subsurface media. We introduce an elliptical Gaussian function to describe local random anomalies. The tapering function is also introduced to reduce calculation errors caused by the numerical simulation of discrete grids. We derive the impedance inversion workflow and test the calculation precision in complex media. Finally, we use impedance inversion to process GPR field data in a polluted site in Mongolia. The inversion results were constrained using borehole data and validated by resistivity data.
基金partially funded by the International Foundation for Science(Grant No:I-1-D-6066-1).
文摘Stem volume estimation is crucial in forest ecology and management,particularly for timber harvesting strategies and carbon stock assessments.This study aimed to develop a variable-exponent taper equation specifically tailored to savanna tree species using close-range photogrammetry(CRP)data and to evaluate its performance against conventional volume equations for stem volume estimation.A dataset of 30 trees across five dominant savanna species was used to fit the taper model,which was validated using a separate dataset of 322 trees from 14 species.The results demonstrated significant improvements in volume estimation accuracy when using the taper equation.At the tree level,the root mean square error(RMSE)decreased by 47%,from 598 to 319 dm^(3),and the mean absolute bias(MAB)by 48%,from 328 to 172 dm3,compared to volume equations.Similarly,at the plot level,RMSE was reduced by 42% and MAB by 40%.The model performed well for species with regular forms.However,species with irregular tapers exhibited higher errors,reflecting the challenges of modeling stem forms of mixed species.The use of CRP proved valuable,providing high-resolution diameter measurements that improved model parameterization.This study underscores the importance of advanced data collection methods for enhancing taper model accuracy and suggests that further species-specific adjustments are needed to improve performance for species with irregular forms.The findings support the broader application of taper equations for improving stem volume estimates in savanna ecosystems,contributing to better forest management and resource monitoring practices.
文摘BACKGROUND Cardiac sarcoidosis(CS)is an infiltrative disease with manifestations such as nonsustained ventricular tachycardia(NSVT)and heart failure(HF).Antiphospholipid syndrome(APS)and antiphospholipid positivity(APP)are prothrombotic phenomena which elevate risk for thromboembolism.CS with active systemic sarcoid and APS/APP is a rare combination of diseases.CASE SUMMARY A 54 year old male with HF presented with several cardiopulmonary symptoms.Chest imaging showed bilateral patchy and reticulonodular infiltrates.Subsequent lung biopsy confirmed pulmonary sarcoidosis.Positron emission tomography revealed active systemic sarcoidosis(SS)and fibrotic CS.Positive antiphospholipid antibodies without thromboembolism confirmed APP.HF and APP were managed with medical therapy.Fibrotic CS and NSVT required permanent cardiac device and antiarrhythmic therapy.SS was managed with early taper of steroids and transition to biologics.CONCLUSION Fibrotic CS with active SS and APS/APP has not been previously described in literature.This case utilized a modified approach for the management of this combination of diseases.As immunosuppressants such as steroids have limited utility in fibrotic sarcoidosis and a potential for thromboembolic complications in the presence of APP,an accelerated transition to non-thrombotic immunosuppressants can be advantageous in the long term treatment of this combination of diseases.
基金supported by the Airlangga University through Mandate Research Grant(Nos.216/UN3.15/PT/2022 and 217/UN3.15/PT/2022)。
文摘This paper presents a biosensor utilizing a whispering gallery mode(WGM)resonator characterized by azimuthal symmetry and crescent-shaped coatings of silver.The study investigates the impact of the coupling gap on the extinction ratio and Q-factor of the setup.The resonator is coated with silver in crescent shapes,ranging from 40 nm to 65 nm in thickness.Coupling is achieved with a silica waveguide,simulating the tapered fiber coupling method.Notably,the resonator exhibits a maximum sensitivity of 220 nm/RIU when coated with 55-nm-thick silver in conjunction with a 4-nm-thick layer of thiol-tethered deoxyribonucleic acid(DNA).This biosensor holds promise for biomolecule detection applications.
基金supported by the National Key Research and Development Program of China (Grant No.2022YFB2803100)the National Major Scientific Research Instrument Development Project(Grant No.22127901)+6 种基金the National Natural Science Foundation of China (Grant No.62305367)the Shanghai Natural Science Foundation (Grant No.25ZR1401379)the Natural Science Foundation of Zhejiang Province,China (Grant No.LZ24F050001)the Innovation Program for Quantum Science and Technology (Grant Nos.2021ZD0301500 and 2021ZD0303200)the National Natural Science Foundation of China (Grant Nos.T2325022,U23A2074,62061160487,and 62275240)the CAS Project for Young Scientists in Basic Research(Grant No.YSBR-049)the Fundamental Research Funds for the Central Universities。
文摘Quantum photonic integrated circuits offer enhanced stability and scalability for quantum communications,sensing, and computing. Transverse modes in multimode waveguides enable high-dimensional scalability and versatile photon manipulation, but practical adoption requires compact and fabrication-tolerant quantum interference devices. Here, we present an ultra-compact taper-stepped beamsplitter that enables quantum interference between photon pairs in different transverse modes, and cascade it to realize NOON state interferometry. We experimentally achieve high visibilities of 93.9% for HOM interference and 86.5% for NOON state interference,demonstrating that efficient mode interference with active tuning can be realized on this platform.
