Quantum cascade lasers(QCLs) have broad application potentials in infrared countermeasure system,free-space optical communication and trace gas detection.Compared with traditional Fabry-Pérot(FP) cavity and exter...Quantum cascade lasers(QCLs) have broad application potentials in infrared countermeasure system,free-space optical communication and trace gas detection.Compared with traditional Fabry-Pérot(FP) cavity and external cavity,distributed feedback quantum cascade lasers(DFB-QCLs) can obtain narrower laser linewidth and higher integration.In this paper,the structure design,numerical simulation and optimization of the Bragg grating of DFB-QCLs are carried out to obtain the transmission spectrum with central wavelength at 4.6 μm.We analyze the relationship among the structure parameters,the central wavelength shift and transmission efficiency using coupled-wave theory and finite-difference time-domain(FDTD) method.It is shown that the increase in the number of grating periods enhances the capabilities of mode selectivity,while the grating length of a single period adjustment directly determines the Bragg wavelength.Additionally,variations in etching depth and duty cycle lead to blue and red shifts in the central wavelength,respectively.Based on the numerical simulation results,the optimized design parameters for the upper buffer layer and the upper cladding grating are proposed,which gives an optional scheme for component fabrication and performance improvement in the future.展开更多
Titanium alloy has the advantages of high strength,strong corrosion resistance,excellent high and low temperature mechanical properties,etc.,and is widely used in aerospace,shipbuilding,weapons and equipment,and other...Titanium alloy has the advantages of high strength,strong corrosion resistance,excellent high and low temperature mechanical properties,etc.,and is widely used in aerospace,shipbuilding,weapons and equipment,and other fields.In recent years,with the continuous increase in demand for medium-thick plate titanium alloys,corresponding welding technologies have also continued to develop.Therefore,this article reviews the research progress of deep penetration welding technology for medium-thick plate titanium alloys,mainly covering traditional arc welding,high-energy beam welding,and other welding technologies.Among many methods,narrow gap welding,hybrid welding,and external energy field assistance welding all contribute to improving the welding efficiency and quality of medium-thick plate titanium alloys.Finally,the development trend of deep penetration welding technology for mediumthick plate titanium alloys is prospected.展开更多
BACKGROUND Early esophageal neuroendocrine carcinoma(E-NEC)is a rare but aggressive malignancy with poorly understood endoscopic features.Despite advancements in multi-model endoscopy,including white light endoscopy,m...BACKGROUND Early esophageal neuroendocrine carcinoma(E-NEC)is a rare but aggressive malignancy with poorly understood endoscopic features.Despite advancements in multi-model endoscopy,including white light endoscopy,magnifying end-oscopy narrow-band imaging(NBI),and endoscopic ultrasonography(EUS),the diagnostic characteristics of early E-NEC remain unclear.Comprehensive evalu-ation using these techniques can improve early detection and guide clinical management.This study aimed to investigate the endoscopic features of early E-NEC using multiple imaging modalities.We hypothesized that specific endos-copic patterns,such as irregular microvascular morphology or signs of submu-cosal invasion,could reliably distinguish early E-NEC from other esophageal lesions.AIM To characterize early E-NEC using multi-model endoscopy and identify diag-nostic endoscopic features.METHODS Clinical data of four patients with esophageal submucosal lesions identified by gastroscopy and pathologically diagnosed as E-NEC in the Department of Gastroenterology,The First Affiliated Hospital of Zhejiang University School of Medicine between January 2020 and August 2024 were retrospectively analyzed,and their manifestations under multi-model endoscopy were observed.Grayscale values of ultrasound images in three patients with E-NEC and eight with esophageal leiomyoma were calculated using Image J software and compared using the Mann-Whitney U test.Neuroendocrine neoplasms(NENs)are a rare heterogeneous group of epithelial tumors that originate from peptidergic neurons and neuroendocrine cells,and are characterized by neuroendocrine differentiation.NENs include well-differen-tiated neuroendocrine tumors(NETs),poorly differentiated neuroendocrine carcinomas(NECs),and mixed neuroen-docrine-non-NENs[1],which exhibit a wide range of biological behaviors,from indolent,slow-growing lesions to highly aggressive and metastatic malignancies[2].NENs have the capacity for whole-body distribution,with gastroenteropan-creatic NENs comprising approximately 60%-75%of cases,followed by those in the lungs and mediastinum[3].Eso-phageal NENs(E-NENs)are extremely rare,accounting for only approximately 1.6%of all NENs and occurring far less frequently than other gastrointestinal NENs[4].However,with advancements in early cancer screening and diagnostic techniques,the incidence of E-NENs has gradually increased in recent decades[5].Among E-NENs,<1%are well-differ-entiated NETs,with the vast majority being poorly differentiated small cell NECs[6,7].Nevertheless,esophageal NEC(E-NEC)accounts for only 0.05%-7.6%of all esophageal malignant tumors[8,9],and is characterized by aggressive behavior,rapid progression,and early metastasis.E-NEC primarily affects middle-aged and older individuals,with a higher prevalence in males[10].The tumor-node-metastasis staging system of E-NEC mirrors that of esophageal squamous cell carcinoma(ESCC)[11,12].Early E-NEC is defined as lesions limited to the mucosal or submucosal layer(stages T1a and T1b),with or without nodal metastasis.Clinically,we found that early E-NEC often presents with absent or non-specific symptoms,such as mild dysphagia or retrosternal discomfort,which are easily overlooked or mistaken for benign esophageal conditions such as leiomyoma.Conventional imaging and tumor markers frequently fail to detect early lesions,and endoscopic biopsy results may be inconclusive due to submucosal tumor growth and the overlying normal epithelium[13].As a result,E-NEC is frequently diagnosed at an advanced stage(31%-90%of cases)when regional lymph node or distant metastases have already occurred,contributing to its poor prognosis[2,13,14].Studies have reported a median survival of approximately 11 months and 5-year survival rate of<10%[14].Given these challenges,early detection using endoscopy is essential for improving patient outcomes.展开更多
Kitaev quantum spin liquids have attracted significant attention in condensed matter physics over the past decade.To understand their emergent quantum phenomena,high-quality single crystals of substantial size are ess...Kitaev quantum spin liquids have attracted significant attention in condensed matter physics over the past decade.To understand their emergent quantum phenomena,high-quality single crystals of substantial size are essential.Here,we report the synthesis of single crystals of the Kitaev quantum spin liquid candidate RuBr_(3),achieving millimeter-sized crystals through a self-flux method under high pressure and high temperature conditions.The crystals exhibit well-defined cleavage planes with a lustrous appearance.Transport characterizations exhibit a narrow band-gap semiconducting behavior with 0.13 eV and 0.11 eV band-gap in ab plane and along𝑐axis,respectively.Magnetic measurement shows a transition to antiferromagnetic(AFM)state at approximately 29K both in ab plane and along the c axis.Notably,the N′eel temperature increases to 34K with an applied magnetic field of up to 7T in the ab plane,but without any change along𝑐axis.The large size and high quality of RuBr3 single crystals provide a valuable platform for investigating various interactions,particularly the Kitaev interaction,and for elucidating the intrinsic physical properties of Kitaev quantum spin liquids.展开更多
BACKGROUND Intracranial blister-like microaneurysms are an extremely rare disease.Rupture of intracranial aneurysms can lead to subarachnoid hemorrhage(SAH).Patients with SAH may experience severe neurological symptom...BACKGROUND Intracranial blister-like microaneurysms are an extremely rare disease.Rupture of intracranial aneurysms can lead to subarachnoid hemorrhage(SAH).Patients with SAH may experience severe neurological symptoms,including severe headache,nausea,vomiting,transient or persistent loss of consciousness,limb weakness,and blurred vision.Ruptured aneurysms should be surgically treated as soon as possible.Intravascular electrocoagulation is becoming a promising treatment method for intracranial blister-like microaneurysms.The short-term follow-up results demonstrated that this method is safe and effective.This article presents a case of endovascular electrocoagulation for the treatment of a blisterlike microaneurysm.CASE SUMMARY This article reports the case of 71-year-old female patient with an intracranial aneurysm.The patient experienced a sudden headache with vomiting for 3 hours.Brain computed tomography(CT)scan showed a subarachnoid hemorrhage.She was diagnosed with rupture of an aneurysm and subarachnoid hemorrhage.The aneurysm was located in the choroidal segment of the right internal carotid artery.The size of the aneurysm was 2.00 mm×1.80 mm×1.97 mm,and the neck of the aneurysm was less than 0.5 mm wide.We successfully treated this aneurysm with endovascular electrocoagulation,and the patient was safely returned to the ward and discharged after subsequent supportive treatment.CT angiography reexamination 3 months after surgery revealed no contrast agent extravasation in the original lesion,with a good prognosis.CONCLUSION Endovascular electrocoagulation is an effective and safe method for the treatment of intracranial blister-like microaneurysms.展开更多
Narrow backfill earth pressure estimation is applied to study the stability of supporting structures in the vicinity of existing buildings.Previous narrow backfill earth pressure studies have neglected seismic-unsatur...Narrow backfill earth pressure estimation is applied to study the stability of supporting structures in the vicinity of existing buildings.Previous narrow backfill earth pressure studies have neglected seismic-unsaturated seepage multi-field coupling,resulting in inaccurate estimates.To address these deficiencies,this paper proposed a calculation method for seismic passive earth pressure in unsaturated narrow backfill,based on inclined thin-layer units.It considers the interlayer shear stress,arching effect,and the multi-field coupling of seismic-unsaturated seepage.Additionally,this paper includes a parametric sensitivity analysis.The outcomes indicate that the earthquake passive ground pressure of unsaturated narrow backfill can be reduced by increasing the aspect ratio,seismic acceleration coefficient,and unsaturation parameterα.It can also be reduced by decreasing the effective interior friction angle,soil cohesion,wallearth friction angle,and vertical discharge.Furthermore,for any width soil,lowering the elevation of the action point of passive thrust can be attained by raising the effective interior friction angle,wall-earth friction angle,and unsaturation parameterα.Reducing soil cohesion,seismic acceleration coefficient,and vertical discharge can also lower the height of the application point of passive thrust.展开更多
We present the first theoretical study on heavy-flavor jet angularities(λ_(α)^(κ))in Pb+Pb collisions at√SNN=5.02 Te V.The initial production of heavy-flavor jets was carried out using the POWHEG+PYTHIA8 prescript...We present the first theoretical study on heavy-flavor jet angularities(λ_(α)^(κ))in Pb+Pb collisions at√SNN=5.02 Te V.The initial production of heavy-flavor jets was carried out using the POWHEG+PYTHIA8 prescription.In contrast,the SHELL transport model describes jet evolution in the quark-gluon plasma(QGP).In p+p collisions,we observed narrower angularity distributions for D ^(0)-tagged jets than for inclusive jets,consistent with the ALICE preliminary results.We then demonstrate that jet quenching in the QGP slightly widens the angularity distribution of D ^(0)-tagged jets in Pb+Pb collisions relative to that in p+p collisions for a jet transverse momentum of 10<pch/T,jet<20 Ge V/c.In contrast,the angularity distributions of the inclusive and D ^(0)-tagged jets become narrower in Pb+Pb collisions relative to p+p atpch/T,jet>20 Ge V/c because of the strong influence of selection bias.Additionally,by comparing the average angularities<λ_(α)^(κ)>of the inclusive,D ^(0)-tagged,and B ^(0)-tagged jets with varyingαandκ,we show that the larger the quark mass,the lower the jet’s<λ_(α)^(κ)>values are.As a result of the slenderer initial distribution,we predict that compared with inclusive jets,heavy-flavor jets,especially B~0-tagged ones,will suffer stronger modifications of<λ_(α)^(κ)>in Pb+Pb relative to p+p at 10<pch/T,jet<20 Ge V/c.For a larger jet radius,a more significant broadening of the jet angularities was predicted because of the enhanced contribution of the wide-angle particles.展开更多
Organic-inorganic hybrid solar cells consisting of organic conjugated materials and inorganic quantum dots(QDs)have been of great interest during the past two decades.However,it is still challenging to select desired ...Organic-inorganic hybrid solar cells consisting of organic conjugated materials and inorganic quantum dots(QDs)have been of great interest during the past two decades.However,it is still challenging to select desired organic functional materials for fabricating hybrid films to maximize their photovoltaic performance.Herein,we report the synthesis of three narrow bandgap non-fullerene conjugated polymers and further demonstrate the importance and impact of polymer crystallinity in tuning the organic-inorganic hybrid interface towards improved photovoltaic performance.In specific,we develop an organic-inorganic hybrid active layer using a newly synthesized polymer with relatively weaker crystallinity and FAPbI_(3)QDs,enabling complementary absorption and favorable interface/morphology for efficient charge separation and transport.The champion PCDOT-T/FAPbI_(3)QD hybrid device achieves a record-high efficiency of 13.11%based on the one-step coating organic/QD hybrid bulk heterojunction blend,which is significantly improved relative to the semi-crystalline polymer PYIT-based hybrid device(11.23%)and pristine QD(10.51%).We believe these findings would provide new insight into the organic/QD interface to construct desired hybrid films for high-performing optoelectronic applications.展开更多
An alternating magnetic field(AMF)was introduced into the narrow gap laser-arc hybrid welding process for 2205 duplex stainless steel thick plates.The corrosion performance of the welded joints was evaluated through e...An alternating magnetic field(AMF)was introduced into the narrow gap laser-arc hybrid welding process for 2205 duplex stainless steel thick plates.The corrosion performance of the welded joints was evaluated through electrochemical studies.The results revealed that joints welded with the application of AMF had a lower corrosion current density compared to those welded without an external AMF.Additionally,these joints showed higher pitting potential and polarization resistance.Microscopic electrochemical analysis indicated that joints subjected to AMF exhibited minimal cathodic current in simulated seawater,with only slight fluctuations in the anodic current peak.Overall,the corrosion levels on the joint surfaces were relatively low.After 4 h of immersion in the corrosive medium,the average impedance of joints exposed to AMF increased by 60.7%compared to those not influenced by a magnetic field.These findings suggest that applying AMF during the narrow gap laser-arc hybrid welding process can significantly improve the corrosion resistance of duplex stainless steel welded joints,reducing their susceptibility to stress corrosion in seawater-like environments.展开更多
Cardiac resynchronization therapy(CRT)reduces heart failure(HF)hospitaliz-ations and all-cause mortality in patients with HF with reduced ejection fraction with left bundle branch(LBB)block.Biventricular pacing(BVP)is...Cardiac resynchronization therapy(CRT)reduces heart failure(HF)hospitaliz-ations and all-cause mortality in patients with HF with reduced ejection fraction with left bundle branch(LBB)block.Biventricular pacing(BVP)is considered the gold standard for achieving CRT;however,approximately 30%–40%of patients do not respond to BVP-CRT.Recent studies have demonstrated that LBB pacing(LBBP)produces remarkable results in CRT.In this meta-analysis,LBBP-CRT showed better outcomes than conventional BVP-CRT,including greater QRS duration reduction and left ventricular ejection fraction improvement,along with consistently lower pacing thresholds on follow-up.Additionally,there was a grea-ter reduction in New York Heart Association class and brain natriuretic peptide levels.This study contributes to the growing body of encouraging data on LBBP-CRT from recent years.With ongoing technological advancements and increasing operator expertise,the day may not be far when LBBP-CRT becomes the standard of care rather than the exception.展开更多
High purity and ultrafine DAAF(u-DAAF)is an emerging insensitive charge in initiators.Although there are many ways to obtain u-DAAF,developing a preparation method with stable operation,accurate control,good quality c...High purity and ultrafine DAAF(u-DAAF)is an emerging insensitive charge in initiators.Although there are many ways to obtain u-DAAF,developing a preparation method with stable operation,accurate control,good quality consistency,equipment miniaturization,and minimum manpower is an inevitable requirement to adapt to the current social technology development trend.Here reported is the microfluidic preparation of u-DAAF with tunable particle size by a passive swirling microreactor.Under the guidance of recrystallization growth kinetics and mixing behavior of fluids in the swirling microreactor,the key parameters(liquid flow rate,explosive concentration and crystallization temperature)were screened and optimized through screening experiments.Under the condition that no surfactant is added and only experimental parameters are controlled,the particle size of recrystallized DAAF can be adjusted from 98 nm to 785 nm,and the corresponding specific surface area is 8.45 m^(2)·g^(-1)to 1.33 m^(2)·g^(-1).In addition,the preparation method has good batch stability,high yield(90.8%-92.6%)and high purity(99.0%-99.4%),indicating a high practical application potential.Electric explosion derived flyer initiation tests demonstrate that the u-DAAF shows an initiation sensitivity much lower than that of the raw DAAF,and comparable to that of the refined DAAF by conventional spraying crystallization method.This study provides an efficient method to fabricate u-DAAF with narrow particle size distribution and high reproducibility as well as a theoretical reference for fabrication of other ultrafine explosives.展开更多
Lessons learned from past experiences push for an alternate way of crop production.In India,adopting high density planting system(HDPS)to boost cotton yield is becoming a growing trend.HDPS has recently been considere...Lessons learned from past experiences push for an alternate way of crop production.In India,adopting high density planting system(HDPS)to boost cotton yield is becoming a growing trend.HDPS has recently been considered a replacement for the current Indian production system.It is also suitable for mechanical harvesting,which reducing labour costs,increasing input use efficiency,timely harvesting timely,maintaining cotton quality,and offering the potential to increase productivity and profitability.This technology has become widespread in globally cotton growing regions.Water management is critical for the success of high density cotton planting.Due to the problem of freshwater availability,more crops should be produced per drop of water.In the high-density planting system,optimum water application is essential to control excessive vegetative growth and improve the translocation of photoassimilates to reproductive organs.Deficit irrigation is a tool to save water without compromising yield.At the same time,it consumes less water than the normal evapotranspiration of crops.This review comprehensively documents the importance of growing cotton under a high-density planting system with deficit irrigation.Based on the current research and combined with cotton production reality,this review discusses the application and future development of deficit irrigation,which may provide theoretical guidance for the sustainable advancement of cotton planting systems.展开更多
High-performance carbon dots(CDs)allowing the application in high-end display devices are highly desirable and usually limited by the absence of simple and easy synthesis methods.In this work,we exploited an easy-to-i...High-performance carbon dots(CDs)allowing the application in high-end display devices are highly desirable and usually limited by the absence of simple and easy synthesis methods.In this work,we exploited an easy-to-implement strategy for the one-step synthesis of green-emitting CDs(G-CDs)with superb optical properties.The G-CDs were synthesized using m-phenylenediamine(m-PD)as a single precursor,and the reaction reacted at 180℃for 12 h The resultant G-CDs exhibit high-purity and excitationindependent green fluorescence with the photoluminescence(PL)peak located at 516 nm,full width at half maximum(FWHM)of 46 nm,and PL quantum yield(QY)of∼80%under the 470nm excitation light.The G-CDs and corresponding composite film prepared with polyvinyl butyral(G-CDs@PVB)exhibit good PL stability after undergoing long-time storage for one year and 360 h exposure under 460nm blue light.The G-CDs@PVB film was used as color-conversion materials in green-emitting light-emitting diode(LED)application,exhibiting a Commission internationale de l’Eclairage(CIE)chromaticity coordinate of(0.21,0.44).The film was also used in CD-based liquid crystal display(CD-LCD)application,achieving a color gamut value of 85%.This work will offer a working basis for the synthesis of high-performance CDs as well as their application in displays.展开更多
Leaf shape is a key trait for plant architecture relating to photosynthesis and transpiration in plants(Lawson et al.,2020).Erect leaves with proper leaf length and width,particularly the upper three leaves in cereal ...Leaf shape is a key trait for plant architecture relating to photosynthesis and transpiration in plants(Lawson et al.,2020).Erect leaves with proper leaf length and width,particularly the upper three leaves in cereal crops,could significantly improve light absorption efficiency in canopy and ultimately increase crop yield(Jiao et al.,2010).Rice leaves initiate at the peripheral zone of shoot apical meristem,then develop along the proximal-distal,adaxial-abaxial,and mediallateral axes to form a flat symmetric architecture(Du et al.,2018).展开更多
Fast radio bursts(FRBs)are short-duration radio transients with mysterious origins.Since their uncertainty,there are very few FRBs observed by different instruments simultaneously.This study presents a detailed analys...Fast radio bursts(FRBs)are short-duration radio transients with mysterious origins.Since their uncertainty,there are very few FRBs observed by different instruments simultaneously.This study presents a detailed analysis of a burst from FRB 20190520B observed by FAST and Parkes at the same time.The spectrum of this individual burst ended at the upper limit of the FAST frequency band and was simultaneously detected by the Parkes telescope in the 1.5–1.8GHz range.By employing spectral energy distribution(SED)and spectral sharpness methods,we confirmed the presence of narrow-band radiation in FRB 20190520B,which is crucial for understanding its radiation mechanisms.Our findings support the narrow-band characteristics that most repeaters exhibit.This work also highlights the necessity of continued multiband observations to explore its periodicity and frequency-dependent properties,contributing to an in-depth understanding of FRB phenomena.展开更多
A widely-wavelength-tunable Brillouin fiber laser(BFL)with improved optical signal-to-noise ratio(OSNR)based on parity-time(PT)symmetric and saturable absorption(SA)effect is present.This novel BFL realizes PT symmetr...A widely-wavelength-tunable Brillouin fiber laser(BFL)with improved optical signal-to-noise ratio(OSNR)based on parity-time(PT)symmetric and saturable absorption(SA)effect is present.This novel BFL realizes PT symmetry and SA effect through polarization-maintaining erbium-doped fiber(PM-EDF)Sagnac loop,which is composed of a PM-EDF,a coupler and two polarization controllers(PCs).By using the inherent birefringence characteristic of PM-EDF,two feedback loops in orthogonal polarization state are formed when the Strokes signal in injected.One of these loops provides gain in the clockwise direction with in the Sagnac loop,while the other loop generates loss in the counterclockwise direction.By adjusting the PCs to control the polarization state of the PM-EDF,a single-longitudinal-mode(SLM)BFL can be achieved,as the PT symmetry is broken when the SA participating stimulated Brillouin scattering(SBS)gain and loss are well-matched and the gain surpasses the coupling coefficient.Compared to previous BFLs,the proposed BFL has a more streamlined structure and a wider wavelength tunable range,at the same time,it is not being limited by the bandwidth of the erbium-doped fiber amplifier while still maintaining narrow linewidth SLM output.Additionally,thanks to SA effect of the PM-EDF,the PT symmetric SBS gain contract is enhanced,resulting in a higher optical signal-to-noise(OSNR).The experimental results show that the laser has a wide tunable range of 1526.088 nm to 1565.498 nm,an improved OSNR of 77 dB,and a fine linewidth as small as 140.5 Hz.展开更多
We report the growth of high-quality single crystals of RhP_(2),and systematically study its structure and physical properties by transport,magnetism,and heat capacity measurements.Single-crystal x-ray diffraction rev...We report the growth of high-quality single crystals of RhP_(2),and systematically study its structure and physical properties by transport,magnetism,and heat capacity measurements.Single-crystal x-ray diffraction reveals that RhP_(2) adopts a monoclinic structure with the cell parameters a=5.7347(10)A,b=5.7804(11)A,and c=5.8222(11)A,space group P2_(1)/c(No.14).The electrical resistivityρ(T)measurements indicate that RhP_(2) exhibits narrow-bandgap behavior with the activation energies of 223.1 meV and 27.4 meV for two distinct regions,respectively.The temperaturedependent Hall effect measurements show electron domain transport behavior with a low charge carrier concentration.We find that RhP_(2) has a high mobilityμ_(e)~210 cm^(2)·V^(-1)·s^(-1)with carrier concentrations n_(e)~3.3×10^(18)cm^(3) at 300 K with a narrow-bandgap feature.The high mobilityμ_(e) reaches the maximum of approximately 340 cm^(2)·V^(-1)·s^(-1)with carrier concentrations n_^(e)~2×10^(18)cm^(-3)at 100 K.No magnetic phase transitions are observed from the susceptibilityχ(T)and specific heat C_(p)(T)measurements of RhP_(2).Our results not only provide effective potential as a material platform for studying exotic physical properties and electron band structures but also motivate further exploration of their potential photovoltaic and optoelectronic applications.展开更多
Near-infrared(NIR)responsive compounds with narrow bandgaps play a crucial role in enhancing the photovoltaic efficiency of organic solar cells(OSCs)by effectively capturing high-energy NIR photons,as well as improvin...Near-infrared(NIR)responsive compounds with narrow bandgaps play a crucial role in enhancing the photovoltaic efficiency of organic solar cells(OSCs)by effectively capturing high-energy NIR photons,as well as improving the NIR sensitivity of organic photodetectors(OPDs)through NIR light detection[1,2].The design principle based on electron-donating and accepting(D−A)structures has led to the development of numerous A−D−A or A−DA’D−A type NIR responsive molecules,such as ITIC and Y6.展开更多
The research prepared two deep ultraviolet(DUV)AlGaN-based multiple quantum well(MQW)samples with the same Al content in the QWs but different well widths(3 nm for Sample A and 2 nm for Sample B).Photoluminescence(PL)...The research prepared two deep ultraviolet(DUV)AlGaN-based multiple quantum well(MQW)samples with the same Al content in the QWs but different well widths(3 nm for Sample A and 2 nm for Sample B).Photoluminescence(PL)measurements reveal that Sample A exhibits only one main PL peak across all measured temperatures,while Sample B displays one main PL peak at low temperatures and two distinct PL peaks at high temperatures.Furthermore,compared with Sample A,Sample B exhibits a more significant temperature-dependent PL peak wavelength blue shift relative to the Varshni curve,a more significant excitation power density-dependent PL peak blue shift accompanied by linewidth broadening,as well as a larger non-radiative recombination related activation energy and higher internal quantum efficiency(IQE).These findings can be explained by the observation that the narrower well width of Sample B induces a more pronounced effect of carrier localization than the wider well width of Sample A,due to the enhanced fluctuation in well width and reduced quantum-confined Stark effect(QCSE).展开更多
基金supported by the Scientific Research Project of Beijing Municipal Education Commission (No.KM202411232020)the Young Backbone Teacher Support Plan (No.YBT202408)the Scientific Researchof Beijing Information Science and Technology University (No.2023XJJ08)。
文摘Quantum cascade lasers(QCLs) have broad application potentials in infrared countermeasure system,free-space optical communication and trace gas detection.Compared with traditional Fabry-Pérot(FP) cavity and external cavity,distributed feedback quantum cascade lasers(DFB-QCLs) can obtain narrower laser linewidth and higher integration.In this paper,the structure design,numerical simulation and optimization of the Bragg grating of DFB-QCLs are carried out to obtain the transmission spectrum with central wavelength at 4.6 μm.We analyze the relationship among the structure parameters,the central wavelength shift and transmission efficiency using coupled-wave theory and finite-difference time-domain(FDTD) method.It is shown that the increase in the number of grating periods enhances the capabilities of mode selectivity,while the grating length of a single period adjustment directly determines the Bragg wavelength.Additionally,variations in etching depth and duty cycle lead to blue and red shifts in the central wavelength,respectively.Based on the numerical simulation results,the optimized design parameters for the upper buffer layer and the upper cladding grating are proposed,which gives an optional scheme for component fabrication and performance improvement in the future.
基金financially supported by the Key Research and Development Program of Ningbo(Grant No.2023Z098)Natural Science Foundation of Inner Mongolia(Grant No.2023MS05040)+1 种基金Shenyang Collaborative Innovation Center Project for Multiple Energy Fields Composite Processing of Special Materials(Grant No.JG210027)Shenyang Key Technology Special Project of The Open Competition Mechanism to Select the Best Solution(Grant Nos.2022210101000827,2022-0-43-048).
文摘Titanium alloy has the advantages of high strength,strong corrosion resistance,excellent high and low temperature mechanical properties,etc.,and is widely used in aerospace,shipbuilding,weapons and equipment,and other fields.In recent years,with the continuous increase in demand for medium-thick plate titanium alloys,corresponding welding technologies have also continued to develop.Therefore,this article reviews the research progress of deep penetration welding technology for medium-thick plate titanium alloys,mainly covering traditional arc welding,high-energy beam welding,and other welding technologies.Among many methods,narrow gap welding,hybrid welding,and external energy field assistance welding all contribute to improving the welding efficiency and quality of medium-thick plate titanium alloys.Finally,the development trend of deep penetration welding technology for mediumthick plate titanium alloys is prospected.
基金Supported by National Natural Science Foundation of China,No.82370570.
文摘BACKGROUND Early esophageal neuroendocrine carcinoma(E-NEC)is a rare but aggressive malignancy with poorly understood endoscopic features.Despite advancements in multi-model endoscopy,including white light endoscopy,magnifying end-oscopy narrow-band imaging(NBI),and endoscopic ultrasonography(EUS),the diagnostic characteristics of early E-NEC remain unclear.Comprehensive evalu-ation using these techniques can improve early detection and guide clinical management.This study aimed to investigate the endoscopic features of early E-NEC using multiple imaging modalities.We hypothesized that specific endos-copic patterns,such as irregular microvascular morphology or signs of submu-cosal invasion,could reliably distinguish early E-NEC from other esophageal lesions.AIM To characterize early E-NEC using multi-model endoscopy and identify diag-nostic endoscopic features.METHODS Clinical data of four patients with esophageal submucosal lesions identified by gastroscopy and pathologically diagnosed as E-NEC in the Department of Gastroenterology,The First Affiliated Hospital of Zhejiang University School of Medicine between January 2020 and August 2024 were retrospectively analyzed,and their manifestations under multi-model endoscopy were observed.Grayscale values of ultrasound images in three patients with E-NEC and eight with esophageal leiomyoma were calculated using Image J software and compared using the Mann-Whitney U test.Neuroendocrine neoplasms(NENs)are a rare heterogeneous group of epithelial tumors that originate from peptidergic neurons and neuroendocrine cells,and are characterized by neuroendocrine differentiation.NENs include well-differen-tiated neuroendocrine tumors(NETs),poorly differentiated neuroendocrine carcinomas(NECs),and mixed neuroen-docrine-non-NENs[1],which exhibit a wide range of biological behaviors,from indolent,slow-growing lesions to highly aggressive and metastatic malignancies[2].NENs have the capacity for whole-body distribution,with gastroenteropan-creatic NENs comprising approximately 60%-75%of cases,followed by those in the lungs and mediastinum[3].Eso-phageal NENs(E-NENs)are extremely rare,accounting for only approximately 1.6%of all NENs and occurring far less frequently than other gastrointestinal NENs[4].However,with advancements in early cancer screening and diagnostic techniques,the incidence of E-NENs has gradually increased in recent decades[5].Among E-NENs,<1%are well-differ-entiated NETs,with the vast majority being poorly differentiated small cell NECs[6,7].Nevertheless,esophageal NEC(E-NEC)accounts for only 0.05%-7.6%of all esophageal malignant tumors[8,9],and is characterized by aggressive behavior,rapid progression,and early metastasis.E-NEC primarily affects middle-aged and older individuals,with a higher prevalence in males[10].The tumor-node-metastasis staging system of E-NEC mirrors that of esophageal squamous cell carcinoma(ESCC)[11,12].Early E-NEC is defined as lesions limited to the mucosal or submucosal layer(stages T1a and T1b),with or without nodal metastasis.Clinically,we found that early E-NEC often presents with absent or non-specific symptoms,such as mild dysphagia or retrosternal discomfort,which are easily overlooked or mistaken for benign esophageal conditions such as leiomyoma.Conventional imaging and tumor markers frequently fail to detect early lesions,and endoscopic biopsy results may be inconclusive due to submucosal tumor growth and the overlying normal epithelium[13].As a result,E-NEC is frequently diagnosed at an advanced stage(31%-90%of cases)when regional lymph node or distant metastases have already occurred,contributing to its poor prognosis[2,13,14].Studies have reported a median survival of approximately 11 months and 5-year survival rate of<10%[14].Given these challenges,early detection using endoscopy is essential for improving patient outcomes.
基金supported by the National Key Research and Development Program of China(Grant Nos.2023YFA1406000 and 2022YFA1403800)the National Natural Science Foundation of China(Grant Nos.12474002,22171283,22203031,12434005,12204515,and 12074175)support of the Young Elite Scientists Sponsorship Program by CAST(Grant No.2022QNRC001)。
文摘Kitaev quantum spin liquids have attracted significant attention in condensed matter physics over the past decade.To understand their emergent quantum phenomena,high-quality single crystals of substantial size are essential.Here,we report the synthesis of single crystals of the Kitaev quantum spin liquid candidate RuBr_(3),achieving millimeter-sized crystals through a self-flux method under high pressure and high temperature conditions.The crystals exhibit well-defined cleavage planes with a lustrous appearance.Transport characterizations exhibit a narrow band-gap semiconducting behavior with 0.13 eV and 0.11 eV band-gap in ab plane and along𝑐axis,respectively.Magnetic measurement shows a transition to antiferromagnetic(AFM)state at approximately 29K both in ab plane and along the c axis.Notably,the N′eel temperature increases to 34K with an applied magnetic field of up to 7T in the ab plane,but without any change along𝑐axis.The large size and high quality of RuBr3 single crystals provide a valuable platform for investigating various interactions,particularly the Kitaev interaction,and for elucidating the intrinsic physical properties of Kitaev quantum spin liquids.
文摘BACKGROUND Intracranial blister-like microaneurysms are an extremely rare disease.Rupture of intracranial aneurysms can lead to subarachnoid hemorrhage(SAH).Patients with SAH may experience severe neurological symptoms,including severe headache,nausea,vomiting,transient or persistent loss of consciousness,limb weakness,and blurred vision.Ruptured aneurysms should be surgically treated as soon as possible.Intravascular electrocoagulation is becoming a promising treatment method for intracranial blister-like microaneurysms.The short-term follow-up results demonstrated that this method is safe and effective.This article presents a case of endovascular electrocoagulation for the treatment of a blisterlike microaneurysm.CASE SUMMARY This article reports the case of 71-year-old female patient with an intracranial aneurysm.The patient experienced a sudden headache with vomiting for 3 hours.Brain computed tomography(CT)scan showed a subarachnoid hemorrhage.She was diagnosed with rupture of an aneurysm and subarachnoid hemorrhage.The aneurysm was located in the choroidal segment of the right internal carotid artery.The size of the aneurysm was 2.00 mm×1.80 mm×1.97 mm,and the neck of the aneurysm was less than 0.5 mm wide.We successfully treated this aneurysm with endovascular electrocoagulation,and the patient was safely returned to the ward and discharged after subsequent supportive treatment.CT angiography reexamination 3 months after surgery revealed no contrast agent extravasation in the original lesion,with a good prognosis.CONCLUSION Endovascular electrocoagulation is an effective and safe method for the treatment of intracranial blister-like microaneurysms.
基金Project(42277175)supported by the National Natural Science Foundation of ChinaProject(NRMSSHR-2022-Z08)supported by the Key Laboratory of Natural Resources Monitoring and Supervision in Southern Hilly Region,Ministry of Natural Resources,China。
文摘Narrow backfill earth pressure estimation is applied to study the stability of supporting structures in the vicinity of existing buildings.Previous narrow backfill earth pressure studies have neglected seismic-unsaturated seepage multi-field coupling,resulting in inaccurate estimates.To address these deficiencies,this paper proposed a calculation method for seismic passive earth pressure in unsaturated narrow backfill,based on inclined thin-layer units.It considers the interlayer shear stress,arching effect,and the multi-field coupling of seismic-unsaturated seepage.Additionally,this paper includes a parametric sensitivity analysis.The outcomes indicate that the earthquake passive ground pressure of unsaturated narrow backfill can be reduced by increasing the aspect ratio,seismic acceleration coefficient,and unsaturation parameterα.It can also be reduced by decreasing the effective interior friction angle,soil cohesion,wallearth friction angle,and vertical discharge.Furthermore,for any width soil,lowering the elevation of the action point of passive thrust can be attained by raising the effective interior friction angle,wall-earth friction angle,and unsaturation parameterα.Reducing soil cohesion,seismic acceleration coefficient,and vertical discharge can also lower the height of the application point of passive thrust.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030008)the National Natural Science Foundation of China(Grant Nos.11935007 and 12035007)+1 种基金supported by the Open Foundation of the Key Laboratory of Quark and Lepton Physics(MOE)(Grant No.QLPL2023P01)the Talent Scientific Star-up Foundation of the China Three Gorges University(CTGU)(Grant No.2024RCKJ013)。
文摘We present the first theoretical study on heavy-flavor jet angularities(λ_(α)^(κ))in Pb+Pb collisions at√SNN=5.02 Te V.The initial production of heavy-flavor jets was carried out using the POWHEG+PYTHIA8 prescription.In contrast,the SHELL transport model describes jet evolution in the quark-gluon plasma(QGP).In p+p collisions,we observed narrower angularity distributions for D ^(0)-tagged jets than for inclusive jets,consistent with the ALICE preliminary results.We then demonstrate that jet quenching in the QGP slightly widens the angularity distribution of D ^(0)-tagged jets in Pb+Pb collisions relative to that in p+p collisions for a jet transverse momentum of 10<pch/T,jet<20 Ge V/c.In contrast,the angularity distributions of the inclusive and D ^(0)-tagged jets become narrower in Pb+Pb collisions relative to p+p atpch/T,jet>20 Ge V/c because of the strong influence of selection bias.Additionally,by comparing the average angularities<λ_(α)^(κ)>of the inclusive,D ^(0)-tagged,and B ^(0)-tagged jets with varyingαandκ,we show that the larger the quark mass,the lower the jet’s<λ_(α)^(κ)>values are.As a result of the slenderer initial distribution,we predict that compared with inclusive jets,heavy-flavor jets,especially B~0-tagged ones,will suffer stronger modifications of<λ_(α)^(κ)>in Pb+Pb relative to p+p at 10<pch/T,jet<20 Ge V/c.For a larger jet radius,a more significant broadening of the jet angularities was predicted because of the enhanced contribution of the wide-angle particles.
基金financially supported by the National Key Research and Development Program of China(2022YFE0110300)the National Natural Science Foundation of China(52261145696 and 52473187)+1 种基金the“111”Projectthe Collaborative Innovation Center of Suzhou Nano Science and Technology,Soochow University。
文摘Organic-inorganic hybrid solar cells consisting of organic conjugated materials and inorganic quantum dots(QDs)have been of great interest during the past two decades.However,it is still challenging to select desired organic functional materials for fabricating hybrid films to maximize their photovoltaic performance.Herein,we report the synthesis of three narrow bandgap non-fullerene conjugated polymers and further demonstrate the importance and impact of polymer crystallinity in tuning the organic-inorganic hybrid interface towards improved photovoltaic performance.In specific,we develop an organic-inorganic hybrid active layer using a newly synthesized polymer with relatively weaker crystallinity and FAPbI_(3)QDs,enabling complementary absorption and favorable interface/morphology for efficient charge separation and transport.The champion PCDOT-T/FAPbI_(3)QD hybrid device achieves a record-high efficiency of 13.11%based on the one-step coating organic/QD hybrid bulk heterojunction blend,which is significantly improved relative to the semi-crystalline polymer PYIT-based hybrid device(11.23%)and pristine QD(10.51%).We believe these findings would provide new insight into the organic/QD interface to construct desired hybrid films for high-performing optoelectronic applications.
基金supported by the National Natural Science Foundation of China(No.52265054)the Inner Mongolia Autonomous Region Natural Science Foundation Project(No.2022ZD03)+3 种基金the Inner Mongolia Autonomous Region Science and Technology Plan Project(No.2020GG0313)the Inner Mongolia Autonomous Region Natural Science Foundation Doctoral Fund Project,(No.2021BS05016)the Construction project of integrated research and development platform for key technologies in the development and processing of new nonferrous metal materials(No.RZ2300001971)the Basic Research Business Fee Project for Autonomous Region Directly Affiliated Universities(Nos.JY20220199 and JY20220028).
文摘An alternating magnetic field(AMF)was introduced into the narrow gap laser-arc hybrid welding process for 2205 duplex stainless steel thick plates.The corrosion performance of the welded joints was evaluated through electrochemical studies.The results revealed that joints welded with the application of AMF had a lower corrosion current density compared to those welded without an external AMF.Additionally,these joints showed higher pitting potential and polarization resistance.Microscopic electrochemical analysis indicated that joints subjected to AMF exhibited minimal cathodic current in simulated seawater,with only slight fluctuations in the anodic current peak.Overall,the corrosion levels on the joint surfaces were relatively low.After 4 h of immersion in the corrosive medium,the average impedance of joints exposed to AMF increased by 60.7%compared to those not influenced by a magnetic field.These findings suggest that applying AMF during the narrow gap laser-arc hybrid welding process can significantly improve the corrosion resistance of duplex stainless steel welded joints,reducing their susceptibility to stress corrosion in seawater-like environments.
文摘Cardiac resynchronization therapy(CRT)reduces heart failure(HF)hospitaliz-ations and all-cause mortality in patients with HF with reduced ejection fraction with left bundle branch(LBB)block.Biventricular pacing(BVP)is considered the gold standard for achieving CRT;however,approximately 30%–40%of patients do not respond to BVP-CRT.Recent studies have demonstrated that LBB pacing(LBBP)produces remarkable results in CRT.In this meta-analysis,LBBP-CRT showed better outcomes than conventional BVP-CRT,including greater QRS duration reduction and left ventricular ejection fraction improvement,along with consistently lower pacing thresholds on follow-up.Additionally,there was a grea-ter reduction in New York Heart Association class and brain natriuretic peptide levels.This study contributes to the growing body of encouraging data on LBBP-CRT from recent years.With ongoing technological advancements and increasing operator expertise,the day may not be far when LBBP-CRT becomes the standard of care rather than the exception.
基金the National Natural Science Foundation of China (Grant No.22105184)Research Fund of SWUST for PhD (Grant No.22zx7175)+1 种基金Sichuan Science and Technology Program (Grant No.2019ZDZX0013)Institute of Chemical Materials Program (Grant No.SXK-2022-03)for financial support。
文摘High purity and ultrafine DAAF(u-DAAF)is an emerging insensitive charge in initiators.Although there are many ways to obtain u-DAAF,developing a preparation method with stable operation,accurate control,good quality consistency,equipment miniaturization,and minimum manpower is an inevitable requirement to adapt to the current social technology development trend.Here reported is the microfluidic preparation of u-DAAF with tunable particle size by a passive swirling microreactor.Under the guidance of recrystallization growth kinetics and mixing behavior of fluids in the swirling microreactor,the key parameters(liquid flow rate,explosive concentration and crystallization temperature)were screened and optimized through screening experiments.Under the condition that no surfactant is added and only experimental parameters are controlled,the particle size of recrystallized DAAF can be adjusted from 98 nm to 785 nm,and the corresponding specific surface area is 8.45 m^(2)·g^(-1)to 1.33 m^(2)·g^(-1).In addition,the preparation method has good batch stability,high yield(90.8%-92.6%)and high purity(99.0%-99.4%),indicating a high practical application potential.Electric explosion derived flyer initiation tests demonstrate that the u-DAAF shows an initiation sensitivity much lower than that of the raw DAAF,and comparable to that of the refined DAAF by conventional spraying crystallization method.This study provides an efficient method to fabricate u-DAAF with narrow particle size distribution and high reproducibility as well as a theoretical reference for fabrication of other ultrafine explosives.
文摘Lessons learned from past experiences push for an alternate way of crop production.In India,adopting high density planting system(HDPS)to boost cotton yield is becoming a growing trend.HDPS has recently been considered a replacement for the current Indian production system.It is also suitable for mechanical harvesting,which reducing labour costs,increasing input use efficiency,timely harvesting timely,maintaining cotton quality,and offering the potential to increase productivity and profitability.This technology has become widespread in globally cotton growing regions.Water management is critical for the success of high density cotton planting.Due to the problem of freshwater availability,more crops should be produced per drop of water.In the high-density planting system,optimum water application is essential to control excessive vegetative growth and improve the translocation of photoassimilates to reproductive organs.Deficit irrigation is a tool to save water without compromising yield.At the same time,it consumes less water than the normal evapotranspiration of crops.This review comprehensively documents the importance of growing cotton under a high-density planting system with deficit irrigation.Based on the current research and combined with cotton production reality,this review discusses the application and future development of deficit irrigation,which may provide theoretical guidance for the sustainable advancement of cotton planting systems.
基金supported by the Jiangsu Funding Program for Excellent Postdoctoral Talent(No.2022ZB369)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘High-performance carbon dots(CDs)allowing the application in high-end display devices are highly desirable and usually limited by the absence of simple and easy synthesis methods.In this work,we exploited an easy-to-implement strategy for the one-step synthesis of green-emitting CDs(G-CDs)with superb optical properties.The G-CDs were synthesized using m-phenylenediamine(m-PD)as a single precursor,and the reaction reacted at 180℃for 12 h The resultant G-CDs exhibit high-purity and excitationindependent green fluorescence with the photoluminescence(PL)peak located at 516 nm,full width at half maximum(FWHM)of 46 nm,and PL quantum yield(QY)of∼80%under the 470nm excitation light.The G-CDs and corresponding composite film prepared with polyvinyl butyral(G-CDs@PVB)exhibit good PL stability after undergoing long-time storage for one year and 360 h exposure under 460nm blue light.The G-CDs@PVB film was used as color-conversion materials in green-emitting light-emitting diode(LED)application,exhibiting a Commission internationale de l’Eclairage(CIE)chromaticity coordinate of(0.21,0.44).The film was also used in CD-based liquid crystal display(CD-LCD)application,achieving a color gamut value of 85%.This work will offer a working basis for the synthesis of high-performance CDs as well as their application in displays.
基金supported by the Open Competition Program of the Top Ten Critical Priorities of Agricultural Science and Technology Innovation for the 14th Five-Year Plan of Guangdong Province(No.2022SDZG05)to Letian Chenthe Major Program of Guangdong Basic and Applied Research(2019B030302006)+3 种基金Laboratory of Lingnan Modern Agriculture Project(NT2021002)to Yaoguang Liuthe Foundation of Hainan Yazhou Bay Seed Laboratory(B23YQ1515,B23CQ15FP)to Rongxin Shenthe National Natural Science Foundation of China(32270698)the Elite Rice Plan of GDRRI(2022YG01)to Qi Liu.
文摘Leaf shape is a key trait for plant architecture relating to photosynthesis and transpiration in plants(Lawson et al.,2020).Erect leaves with proper leaf length and width,particularly the upper three leaves in cereal crops,could significantly improve light absorption efficiency in canopy and ultimately increase crop yield(Jiao et al.,2010).Rice leaves initiate at the peripheral zone of shoot apical meristem,then develop along the proximal-distal,adaxial-abaxial,and mediallateral axes to form a flat symmetric architecture(Du et al.,2018).
基金supported by the National Natural Science Foundation of China(Grant Nos.11988101,12203069,12041302,and 12203045)the National SKA Program of China(Grant No.2022SKA0130100)+8 种基金the Office of the Leading Group for Cyberspace Affairs,CAS(Grant No.CAS-WX2023PY0102)the CAS Youth Interdisciplinary Team and the Foundation of Guizhou Provincial Education Department(Grant No.KY(2023)059)support from the National Natural Science Foundation of China(Grant Nos.11988101 and 12041303)the CAS Youth Interdisciplinary Team,the Youth Innovation Promotion Association CAS(Grant No.2021055)the Cultivation Project for FAST Scientific Payoff and Research Achievement of CAMS-CASsupported by the National Natural Science Foundation of China(Grant No.12203045)the Leading Innovation and Entrepreneurship Team of Zhejiang Province of China(Grant No.2023R01008)the Key R&D Program of Zhejiang(Grant No.2024SSYS0012)supported by the China Scholarship Council(Grant No.202304910441)。
文摘Fast radio bursts(FRBs)are short-duration radio transients with mysterious origins.Since their uncertainty,there are very few FRBs observed by different instruments simultaneously.This study presents a detailed analysis of a burst from FRB 20190520B observed by FAST and Parkes at the same time.The spectrum of this individual burst ended at the upper limit of the FAST frequency band and was simultaneously detected by the Parkes telescope in the 1.5–1.8GHz range.By employing spectral energy distribution(SED)and spectral sharpness methods,we confirmed the presence of narrow-band radiation in FRB 20190520B,which is crucial for understanding its radiation mechanisms.Our findings support the narrow-band characteristics that most repeaters exhibit.This work also highlights the necessity of continued multiband observations to explore its periodicity and frequency-dependent properties,contributing to an in-depth understanding of FRB phenomena.
文摘A widely-wavelength-tunable Brillouin fiber laser(BFL)with improved optical signal-to-noise ratio(OSNR)based on parity-time(PT)symmetric and saturable absorption(SA)effect is present.This novel BFL realizes PT symmetry and SA effect through polarization-maintaining erbium-doped fiber(PM-EDF)Sagnac loop,which is composed of a PM-EDF,a coupler and two polarization controllers(PCs).By using the inherent birefringence characteristic of PM-EDF,two feedback loops in orthogonal polarization state are formed when the Strokes signal in injected.One of these loops provides gain in the clockwise direction with in the Sagnac loop,while the other loop generates loss in the counterclockwise direction.By adjusting the PCs to control the polarization state of the PM-EDF,a single-longitudinal-mode(SLM)BFL can be achieved,as the PT symmetry is broken when the SA participating stimulated Brillouin scattering(SBS)gain and loss are well-matched and the gain surpasses the coupling coefficient.Compared to previous BFLs,the proposed BFL has a more streamlined structure and a wider wavelength tunable range,at the same time,it is not being limited by the bandwidth of the erbium-doped fiber amplifier while still maintaining narrow linewidth SLM output.Additionally,thanks to SA effect of the PM-EDF,the PT symmetric SBS gain contract is enhanced,resulting in a higher optical signal-to-noise(OSNR).The experimental results show that the laser has a wide tunable range of 1526.088 nm to 1565.498 nm,an improved OSNR of 77 dB,and a fine linewidth as small as 140.5 Hz.
基金supported by the National Key Research and Development Program of China (Grant No.2017YFA0302901)the Strategic Priority Research Program,the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences (Grant No.XDB33010100)+3 种基金the National Natural Science Foundation of China (Grant Nos.12134018,11921004,and 11634015)the Foundation of Quantum Science Center of Guangdong–Hong Kong–Macao Greater Bay Area,China (Grant No.QD2301005)the Postdoctoral Science Foundation of China (Grant No.2021M693370)the Synergetic Extreme Condition User Facility (SECUF)。
文摘We report the growth of high-quality single crystals of RhP_(2),and systematically study its structure and physical properties by transport,magnetism,and heat capacity measurements.Single-crystal x-ray diffraction reveals that RhP_(2) adopts a monoclinic structure with the cell parameters a=5.7347(10)A,b=5.7804(11)A,and c=5.8222(11)A,space group P2_(1)/c(No.14).The electrical resistivityρ(T)measurements indicate that RhP_(2) exhibits narrow-bandgap behavior with the activation energies of 223.1 meV and 27.4 meV for two distinct regions,respectively.The temperaturedependent Hall effect measurements show electron domain transport behavior with a low charge carrier concentration.We find that RhP_(2) has a high mobilityμ_(e)~210 cm^(2)·V^(-1)·s^(-1)with carrier concentrations n_(e)~3.3×10^(18)cm^(3) at 300 K with a narrow-bandgap feature.The high mobilityμ_(e) reaches the maximum of approximately 340 cm^(2)·V^(-1)·s^(-1)with carrier concentrations n_^(e)~2×10^(18)cm^(-3)at 100 K.No magnetic phase transitions are observed from the susceptibilityχ(T)and specific heat C_(p)(T)measurements of RhP_(2).Our results not only provide effective potential as a material platform for studying exotic physical properties and electron band structures but also motivate further exploration of their potential photovoltaic and optoelectronic applications.
基金supported by the National Natural Science Foundation of China (52263019)the Yunnan Fundamental Research Projects (202301AT070313).
文摘Near-infrared(NIR)responsive compounds with narrow bandgaps play a crucial role in enhancing the photovoltaic efficiency of organic solar cells(OSCs)by effectively capturing high-energy NIR photons,as well as improving the NIR sensitivity of organic photodetectors(OPDs)through NIR light detection[1,2].The design principle based on electron-donating and accepting(D−A)structures has led to the development of numerous A−D−A or A−DA’D−A type NIR responsive molecules,such as ITIC and Y6.
基金supported by the National Natural Science Foundation of China(Nos.62135013,62274163 and 52272157)the Wuxi Innovation and Entrepreneurship Fund“Taihu Light”Science and Technology(Fundamental Research)Project(No.K20231002)。
文摘The research prepared two deep ultraviolet(DUV)AlGaN-based multiple quantum well(MQW)samples with the same Al content in the QWs but different well widths(3 nm for Sample A and 2 nm for Sample B).Photoluminescence(PL)measurements reveal that Sample A exhibits only one main PL peak across all measured temperatures,while Sample B displays one main PL peak at low temperatures and two distinct PL peaks at high temperatures.Furthermore,compared with Sample A,Sample B exhibits a more significant temperature-dependent PL peak wavelength blue shift relative to the Varshni curve,a more significant excitation power density-dependent PL peak blue shift accompanied by linewidth broadening,as well as a larger non-radiative recombination related activation energy and higher internal quantum efficiency(IQE).These findings can be explained by the observation that the narrower well width of Sample B induces a more pronounced effect of carrier localization than the wider well width of Sample A,due to the enhanced fluctuation in well width and reduced quantum-confined Stark effect(QCSE).
