BACKGROUND The incidence of prostate cancer(PCa)is on the rise in China.The risk level of patients with PCa is associated with disease-free survival rate at 10 years after radical prostatectomy.Predicting prognosis in...BACKGROUND The incidence of prostate cancer(PCa)is on the rise in China.The risk level of patients with PCa is associated with disease-free survival rate at 10 years after radical prostatectomy.Predicting prognosis in advance according to the degree of risk can provide a reference for patients,especially treatment options and postoperative adjuvant treatment measures for high-risk/extremely high-risk patients.AIM To explore the predictive value of the prognostic nutritional index(PNI)for biological recurrence in Chinese patients with high/extremely high-risk PCa after radical prostatectomy.METHODS The biochemical test results and clinical data of 193 patients who underwent radical prostatectomy for the first time from January 2015 to December 2020 were retrospectively collected.The PNI value of peripheral blood within 1 wk before surgery was calculated,and during the follow-up period,prostate-specific antigen≥0.2 ng/mL was considered to have biological recurrence.The receiver operating characteristic(ROC)curve was used to calculate the optimal critical value and area under the curve(AUC)of the patients.According to the critical value,the progression-free survival of the high PNI group and low PNI group was compared.The independent influencing factors of the patients’prognosis were obtained by the Cox proportional hazards regression model.RESULTS The non-biological recurrence rates at 1,3,and 5 years were 92.02%,84.05%,and 74.85%,respectively.The optimal critical value for PNI to predict biological recurrence was 46.23,and the AUC was 0.789(95%confidence interval:0.651-0.860;P<0.001).The sensitivity and specificity were 82.93%and 62.30%,respectively.In accordance with the optimal critical value of the ROC curve(46.23),193 patients were further divided into a high PNI group(PNI≤46.23,n=108)and low PNI group(PNI>46.23,n=85).The incidence of postoperative complications in the high PNI group was lower than that in the low PNI group(21.18%vs 38.96%).Kaplan-Meier survival analysis showed that the overall survival rate at 5 years in the low PNI group was 87.96%(13/108),which was lower than that in the high PNI group(61.18%,33/85;P<0.05).Low PNI[hazard ratio(HR)=1.74;P=0.003]and positive incisal margin status(HR=2.14;P=0.001)were independent predictors of biological recurrence in patients with high/extremely high-risk PCa.CONCLUSION The PNI has predictive value for the prognosis of patients with high/extremely high-risk PCa,and is an independent prognostic factor.Patients with low PNI value have a shorter time of nonbiological recurrence after prostatectomy.It is expected that the combined prediction of other clinicopathological data will further improve the accuracy and guide postoperative adjuvant therapy to improve the quality of prognosis.展开更多
Three extreme cold events occurred in eastern Asia in January 2016,January 2021,and December 2023.As important factors in atmospheric circulation anomalies,the Blocking High and East Asian Trough(BH-ET)structure playe...Three extreme cold events occurred in eastern Asia in January 2016,January 2021,and December 2023.As important factors in atmospheric circulation anomalies,the Blocking High and East Asian Trough(BH-ET)structure played key roles during these three extreme cold wave events.Among these two dynamic patterns,the BH affected the development of the cold waves in two different ways:(1)before the cold waves in 2016 and 2023,the BH pushed the cold air southward,resulting in a slow and gradual cooling,with a cooling rate(CR)in eastern Asia of 1.34℃d^(-1)and 1.2℃d^(-1),respectively,and(2)in January 2021,the sudden collapse of BH caused the cold air to rapidly attack mid-latitude regions,with a CR of 1.87℃d^(-1).In terms of the spatial CR,the temperature drop in 2021 occurred 38.8%and 55%faster than those in 2016 and 2023,respectively.At the same time,the ET influences the wind direction of cold waves by modulating the pressure gradient.Before the cold waves occurred,the meridional wind field near the ET showed negative values,forming northwesterly or northeasterly winds,which continued to affect the southern part of East Asia.The meridional wind in January 2021 was stronger than those in 2016 and 2023,which is thought to be the reason for the strength of the 2021 cold wave.Finally,results from the temperature Empirical Orthogonal Function(EOF)analysis from 1980-2023 verify an obvious BH-ET structure in the three cold wave events,which suggests that this particular climatological state provides a climatic background for the occurrence of cold waves.展开更多
Sodium-ion batteries have emerged as competitive substitutes for low-temperature applications due to severe capacity loss and safety concerns of lithium-ion batteries at−20°C or lower.However,the key capability o...Sodium-ion batteries have emerged as competitive substitutes for low-temperature applications due to severe capacity loss and safety concerns of lithium-ion batteries at−20°C or lower.However,the key capability of ultrafast charging at ultralow temperature for SIBs is rarely reported.Herein,a hybrid of Bi nanoparticles embedded in carbon nanorods is demonstrated as an ideal material to address this issue,which is synthesized via a high temperature shock method.Such a hybrid shows an unprecedented rate performance(237.9 mAh g^(−1) at 2 A g^(−1))at−60℃,outperforming all reported SIB anode materials.Coupled with a Na_(3)V_(2)(PO_(4))_(3)cathode,the energy density of the full cell can reach to 181.9 Wh kg^(−1) at−40°C.Based on this work,a novel strategy of high-rate activation is proposed to enhance performances of Bi-based materials in cryogenic conditions by creating new active sites for interfacial reaction under large current.展开更多
East Asia is a region characterized by a typical monsoon climate,which is accompanied by strong precipitation with complex spatiotemporal variability during summer.Previous works have emphasized the impact of tropical...East Asia is a region characterized by a typical monsoon climate,which is accompanied by strong precipitation with complex spatiotemporal variability during summer.Previous works have emphasized the impact of tropical signals on extreme summer precipitation over East Asia,but the roles of the mid-high latitude cyclones are still unclear.Using a reanalysis dataset,this study discloses the synergistic influences of anomalous signals from different latitudes on the extreme precipitation event in the Beijing-Tianjin-Hebei(BTH)region during the summer of 2023.The main conclusions are obtained as follows:the decreased sea ice density caused more Arctic cyclones to generate at positions further west in the Barents Sea and the west of the Kara Sea and then move southeast to East Asia in 2023.Furthermore,the synergistic influences of the outward Arctic cyclones and anomalous signals from middle and low latitudes are discussed.First,the significant northward jump of the Western Pacific Subtropical High(WPSH)provid-ed the favorable condition of large-scale background circulation for summer precipitation in the BTH region in 2023.In addition,the southward intrusion of the Arctic cyclones and the mid-latitude zonal wave trains transported massive cold air to the BTH region.Subsequently,the cold air masses met with the warm moist air carried by the landfall typhoon‘Doksuri’,which generated strong fronts and triggered the extreme precipitation on July 29.However,another severe typhoon,‘Kanu’,generated and moved northward from the tropical Pacific,which caused the further northward shift of the WPSH and the termination of this persistent extreme precipitation on August 1.展开更多
Blast furnace(BF)burden surface contains the most abundant,intuitive and credible smelting information and acquiring high-definition and high-brightness optical images of which is essential to realize precise material...Blast furnace(BF)burden surface contains the most abundant,intuitive and credible smelting information and acquiring high-definition and high-brightness optical images of which is essential to realize precise material charging control,optimize gas flow distribution and improve ironmaking efficiency.It has been challengeable to obtain high-quality optical burden surface images under high-temperature,high-dust,and extremelydim(less than 0.001 Lux)environment.Based on a novel endoscopic sensing detection idea,a reverse telephoto structure starlight imaging system with large field of view and large aperture is designed.Combined with a water-air dual cooling intelligent self-maintenance protection device and the imaging system,a starlight high-temperature industrial endoscope is developed to obtain clear optical burden surface images stably under the harsh environment.Based on an endoscope imaging area model,a material flow trajectory model and a gas-dust coupling distribution model,an optimal installation position and posture configuration method for the endoscope is proposed,which maximizes the effective imaging area and ensures large-area,safe and stable imaging of the device in a confined space.Industrial experiments and applications indicate that the proposed method obtains clear and reliable large-area optical burden surface images and reveals new BF conditions,providing key data support for green iron smelting.展开更多
A nonlinear multi-scale interaction(NMI)model was proposed and developed by the first author for nearly 30 years to represent the evolution of atmospheric blocking.In this review paper,we first review the creation and...A nonlinear multi-scale interaction(NMI)model was proposed and developed by the first author for nearly 30 years to represent the evolution of atmospheric blocking.In this review paper,we first review the creation and development of the NMI model and then emphasize that the NMI model represents a new tool for identifying the basic physics of how climate change influences mid-to-high latitude weather extremes.The building of the NMI model took place over three main periods.In the 1990s,a nonlinear Schr?dinger(NLS)equation model was presented to describe atmospheric blocking as a wave packet;however,it could not depict the lifetime(10-20 days)of atmospheric blocking.In the 2000s,we proposed an NMI model of atmospheric blocking in a uniform basic flow by making a scale-separation assumption and deriving an eddyforced NLS equation.This model succeeded in describing the life cycle of atmospheric blocking.In the 2020s,the NMI model was extended to include the impact of a changing climate mainly by altering the basic zonal winds and the magnitude of the meridional background potential vorticity gradient(PVy).Model results show that when PVy is smaller,blocking has a weaker dispersion and a stronger nonlinearity,so blocking can be more persistent and have a larger zonal scale and weaker eastward movement,thus favoring stronger weather extremes.However,when PVy is much smaller and below a critical threshold under much stronger winter Arctic warming of global warming,atmospheric blocking becomes locally less persistent and shows a much stronger westward movement,which acts to inhibit local cold extremes.Such a case does not happen in summer under global warming because PVy fails to fall below the critical threshold.Thus,our theory indicates that global warming can render summer-blocking anticyclones and mid-to-high latitude heatwaves more persistent,intense,and widespread.展开更多
This paper expounds upon a novel target detection methodology distinguished by its elevated discriminatory efficacy,specifically tailored for environments characterized by markedly low luminance levels.Conventional me...This paper expounds upon a novel target detection methodology distinguished by its elevated discriminatory efficacy,specifically tailored for environments characterized by markedly low luminance levels.Conventional methodologies struggle with the challenges posed by luminosity fluctuations,especially in settings characterized by diminished radiance,further exacerbated by the utilization of suboptimal imaging instrumentation.The envisioned approach mandates a departure from the conventional YOLOX model,which exhibits inadequacies in mitigating these challenges.To enhance the efficacy of this approach in low-light conditions,the dehazing algorithm undergoes refinement,effecting a discerning regulation of the transmission rate at the pixel level,reducing it to values below 0.5,thereby resulting in an augmentation of image contrast.Subsequently,the coiflet wavelet transform is employed to discern and isolate high-discriminatory attributes by dismantling low-frequency image attributes and extracting high-frequency attributes across divergent axes.The utilization of CycleGAN serves to elevate the features of low-light imagery across an array of stylistic variances.Advanced computational methodologies are then employed to amalgamate and conflate intricate attributes originating from images characterized by distinct stylistic orientations,thereby augmenting the model’s erudition potential.Empirical validation conducted on the PASCAL VOC and MS COCO 2017 datasets substantiates pronounced advancements.The refined low-light enhancement algorithm yields a discernible 5.9%augmentation in the target detection evaluation index when compared to the original imagery.Mean Average Precision(mAP)undergoes enhancements of 9.45%and 0.052%in low-light visual renditions relative to conventional YOLOX outcomes.The envisaged approach presents a myriad of advantages over prevailing benchmark methodologies in the realm of target detection within environments marked by an acute scarcity of luminosity.展开更多
Magnetoresistance(MR)is a pivotal transport phenomenon within the realm of condensed matter physics.In recent years,materials exhibiting extremely large unsaturated magnetoresistance(XMR),which are often potential top...Magnetoresistance(MR)is a pivotal transport phenomenon within the realm of condensed matter physics.In recent years,materials exhibiting extremely large unsaturated magnetoresistance(XMR),which are often potential topological materials,have garnered significant attention.In this study,we synthesized single crystals of ZrBi_(2) and performed electrical and specific heat measurements on them.The resistivity of ZrBi_(2) displays metallic behavior with a high residual resistance ratio.Notably,the MR of ZrBi_(2) reaches approximately 2.0×10^(3)%at 2 K and 16 T without saturation.Weak Shubnikov-de Haas oscillations with two frequencies were observed above 13.5 T,which correspond to 237 T and 663 T.Hall effect fitting yields nearly equal concentrations of electron and hole carriers with concentrations of approximately 10^(21)cm^(-3)and mobilities of approximately 5000 cm^(2)·V^(-1)·s^(-1)at 2 K.The XMR could be attributed to the electron-hole compensation with high mobility.展开更多
The extreme removal of SiO2 and MnO inclusions in 304 stainless steel in supergravity fields was investigated using an inhouse high-temperature supergravity equipment.The influences of the gravity coefficient and sepa...The extreme removal of SiO2 and MnO inclusions in 304 stainless steel in supergravity fields was investigated using an inhouse high-temperature supergravity equipment.The influences of the gravity coefficient and separation time on the removal efficiency of the inclusions were studied.After supergravity treatment,the inclusions migrated to the top of the sample and formed large aggregates.Meanwhile,the lower part of the sample was purified considerably and appeared significantly cleaner than the raw material.At the gravity coefficient of 500 and separation time of 600 s,the total oxygen content at the bottom of the sample(position E)decreased from 240 to 28 ppm.This corresponded to a total oxygen removal rate of 88.33%.The volume fraction and number density of inclusions exhibited a gradient distribution along the supergravity direction,with values of 8.5%and 106 mm^(-2) at the top of the sample(position A)and 0.06%and 22 mm^(-2) at its bottom.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
Subseasonal forecasting of extreme events is crucial for early warning systems.However,the forecast skills for extreme events are limited.Taking the extreme cold events in January 2018 as a specific example,and analyz...Subseasonal forecasting of extreme events is crucial for early warning systems.However,the forecast skills for extreme events are limited.Taking the extreme cold events in January 2018 as a specific example,and analyzing the 34 extreme cold events in East Asia from 1998 to 2020,the authors evaluated the forecast skills of the ECMWF model ensemble members on subseasonal time scales.The results show that while the ensemble mean has limited skills for forecasting extreme cold events at the 3-week lead time,some individual members demonstrate high forecast skills.For most extreme cold events,there are>10%of members among the total ensembles that can well predict the rapid temperature transitions at the 14-day lead time.This highlights the untapped potential of the ECMWF model to forecast extreme cold events on subseasonal time scales.High-skill ensemble members rely on accurate predictions of atmospheric circulation patterns(500-hPa geopotential height,mean sea level pressure)and key weather systems,including the Ural Blocking and Siberian High,that influence extreme cold events.展开更多
A numerical simulation was performed using the Thompson microphysics scheme to preliminarily investigate the features of the microphysical processes involved in the record-breaking rainfall event that occurred in Hena...A numerical simulation was performed using the Thompson microphysics scheme to preliminarily investigate the features of the microphysical processes involved in the record-breaking rainfall event that occurred in Henan Province,China,on 20 July 2021.The simulation results showed that a strong meso-𝛾-scale vortical updraft was concurrent with the torrential rainfall.The main finding is that this event was characterized by typical midlatitude warm-rain processes.The simulation with the Thompson microphysics scheme further indicated that highly efficient collision-coalescence of cloud water to rainwater resulted in a considerably active rain droplet growth,leading to this record-breaking rainfall event.展开更多
The Sichuan Basin(SCB),China has a high incidence of extremely persistent heavy rainfall(EPHR)events.The EPHR events from 2009 to 2019 in the SCB were mainly concentrated over the northern and northwestern windward sl...The Sichuan Basin(SCB),China has a high incidence of extremely persistent heavy rainfall(EPHR)events.The EPHR events from 2009 to 2019 in the SCB were mainly concentrated over the northern and northwestern windward slopes and the central basin.They occurred from June to September,but especially in July,and peaked at 0300 LST.ERA5 reanalysis data and objective classification were used to investigate the synoptic patterns and their effects.There were three synoptic patterns during EPHR events,all accompanied by a Southwest Vortex.The location and intensity of the Southwest Vortex,thermal forcing of the Tibetan Plateau(TP),and low-level winds can greatly affect the intensity and spatial distribution of EPHR.When the Southwest Vortex was located in the western SCB and there were southerly low-level jets(LLJs),convergence and upslope wind would lead to EPHR over the northwestern or northern windward slopes.If there was no LLJ and the whole SCB was under the center of the Southwest Vortex,nocturnal EPHR was controlled by the internal circulation of the Southwest Vortex and the updraft generated by the thermal forcing of the TP,and the rainfall was weaker.The southeastern entrance of the SCB was a key area where the low-level wind dominated the nocturnal peak of EPHR.The nocturnal strengthened southeasterly wind in the key area is attributable to inertial oscillation,and the topographic friction plays an essential role in transporting momentum and moisture into the basin by generating easterly and northeasterly ageostrophic winds.展开更多
In Xinjiang,China,Oil-immersed paper bushings used in reactors are highly susceptible to discharge breakdown faults due to drastic fluctuations in environmental and oil temperatures.To mitigate this problem,oil-free a...In Xinjiang,China,Oil-immersed paper bushings used in reactors are highly susceptible to discharge breakdown faults due to drastic fluctuations in environmental and oil temperatures.To mitigate this problem,oil-free and explosion-proof epoxy resin-impregnated paper(ERIP)bushings are recommended as replacements.This study develops a multi-physics(electric-thermal-fluid)coupling model for 750 kV high voltage reactors ERIP bushings.The model aims to comprehensively assess their thermal and electrical performance under extreme ambient temperatures ranging from−40℃ to 90℃ and oil temperatures varying from−10℃ to 90℃.The results demonstrate that the bushing temperature rises consistently with increases in ambient temperature.Additionally,the location of the hottest point on the conductive rod exhibits an upward shift as the ambient temperature climbs.Significantly,when a temperature difference exists between the oil and the external environment,this upward movement remains relatively constrained.Even when the external temperature increases from−40℃ to 80℃,the hottest point shifts upward only 2457 mm.Conversely,in the absence of a temperature difference between the oil and external environment,a modest 10℃ increase in ambient temperature(from 80℃ to 90℃)triggers a substantial 11,356 mm upward displacement of the hottest point.Moreover,this study reveals that the electric field distribution within the bushings remains largely unaffected by environmental temperature changes.展开更多
In the summer of 2024, following a strong El Ni?o event in the preceding winter, the tropical Indian Ocean and tropical North Atlantic recorded their highest SSTs since 1961, along with a significant westward shift an...In the summer of 2024, following a strong El Ni?o event in the preceding winter, the tropical Indian Ocean and tropical North Atlantic recorded their highest SSTs since 1961, along with a significant westward shift and intensification of the western Pacific subtropical high(WPSH). Under these conditions, China experienced its hottest summer since 1961,and was hit by a series of high-impact extreme weather and climate events. From 9 June to 2 July, southern China experienced an unprecedented extreme precipitation event that exceeded the well-known 1998 summer precipitation event in both duration and impact scope, resulting in devastating floods in the Yangtze River basin. Subsequently, in early to midJuly, the Huanghe-Huaihe Basin suffered from a severe drought–flood abrupt alternation event, heavily affecting Henan and Shandong. Meanwhile, southern China underwent a widespread heatwave event lasting 74 days, ranking as the second most intense since 1961. From late July to the end of August, northern China faced unusually frequent heavy precipitation events, with cumulative precipitation reaching the second highest for the same period since 1961, causing floods in many rivers of northern China. This study provides a timely summary and assessment of the characteristics and impacts of these extreme events. It serves as a reference for climate change research, including mechanism analysis, numerical simulation,and climate event attribution, and also offers valuable insights for improving meteorological disaster prevention and mitigation strategies.展开更多
The increase in frequency and intensity of Extreme High-temperature Events(EHEs)over Central-Eastern China(CEC)in recent decades has severely impacted social development and livelihoods.Using observation and reanalysi...The increase in frequency and intensity of Extreme High-temperature Events(EHEs)over Central-Eastern China(CEC)in recent decades has severely impacted social development and livelihoods.Using observation and reanalysis datasets,this study explores the effect of the East Asian subtropical westerly jet stream(EAJ)on the CEC EHEs for the summers spanning 1979–2020.Considering its general relative location to the right side of the upper-level jet stream exit region,CEC would theoretically suffer more EHEs with a stronger and northwardly-shifted EAJ in summer due to the likelihood of abnormal subsidence induced by the EAJ.However,such an EAJ–EHE connection has been unstable over the past four decades but has displayed an evident interdecadal change.Before the late 1990s,the interannual variation of the EAJ was manifested mainly by its meridional displacement in the northeastern part of East Asia;thus,the atmospheric responses were essentially located to the east of CEC,exerting less of an influence on the CEC EHEs.However,since the late 1990s,the EAJ variation has featured an intensity change in its center over the northwest portion of the CEC,which has resulted in a westward shift in atmospheric responses to cover the CEC region.Therefore,the EAJ could potentially affect the summer CEC EHEs during 2000–21.Our findings offer support for an in-depth understanding of the formation mechanisms of extreme weather/climate events of this nature and thus provide a scientific reference for seasonal climate predictions.展开更多
The implementation of the ecological protection red line serves as a crucial protective barrier for the conservation of wild plants with extremely small populations by delineating specific geographical areas designate...The implementation of the ecological protection red line serves as a crucial protective barrier for the conservation of wild plants with extremely small populations by delineating specific geographical areas designated for their conservation.The implementation of a comprehensive set of conservation measures aimed at establishing a biodiversity conservation network for wild plants with extremely small populations has laid the foundation for the health and stability of ecosystems,as well as the harmonious coexistence of humans and the natural environment.Research on the conservation of wild plants with extremely small populations serves as a critical foundation for informing and enhancing the effective conservation of such populations.This paper provides a systematic examination of the theoretical and practical conservation status of certain wild plants with extremely small populations and discusses the conservation trends of these populations within the framework of ecological protection red line delineation.In the future,strategies for the conservation of wild plants with extremely small populations should be integrated with an analysis of the causes of endangerment.This approach will provide a robust foundation for applied research focused on the conservation of these vulnerable plant populations.展开更多
In extremely close-distance coal seam(ECDCS)mining,section coal pillars remain after upper coal seam(UCS)extraction.Thus,for layout and support design of lower coal seam(LCS)mining roadways,it is critical to account f...In extremely close-distance coal seam(ECDCS)mining,section coal pillars remain after upper coal seam(UCS)extraction.Thus,for layout and support design of lower coal seam(LCS)mining roadways,it is critical to account for UCS goaf deterioration and residual coal pillar(RCP)-induced stress disturbance.Taking the 6.4 m layer spacing of ECDCS mining in Nanyangpo Coal Mine as a case study,this research aimed to determine the optimal layout and surrounding rock control method for the 24202-ventilation roadway in the RCP area.First,the challenges of roadway layout and support under RCP were clarified:three layout methods face distinct RCPinduced stress disturbances and goaf-related roof damage.A finite element model was established;the second invariant of deviatoric stress(J_(2))and horizontal stress index were introduced to analyze plastic zone and stress evolution after UCS mining.Results show that J_(2)distributes symmetrically,with its peak diffusing downward and attenuating in a“/”-shaped pattern.Six schemes were simulated to compare plastic zone distributions at different positions,revealing that the optimal layout consists of a roadway alignment with the RCP center.Based on roadway layout and roof conditions,a cooperative control scheme was proposed:deep,strong anchorage with long cables across the RCP,and shallow stable support with short bolts in the ECDCS.This scheme secures roof cables anchored to the UCS RCP roof to achieve cross-seam anchorage.On-site borehole peeping and loose circle tests confirm smooth surrounding rock hole walls and limited failure range.Specifically,surrounding rock deformation and roof separation were controlled within 200 mm and 80 mm,respectively,with stable bolt/cable support resistance.These results offer an innovative solution for roadway layout design and support strategies under RCP in ECDCS,with significant engineering application value.展开更多
Extremely large-scale array(XL-array)communications can significantly improve the transmission rate,spectral efficiency,and spatial resolution,and has great potential in next-generation mobile communication networks.A...Extremely large-scale array(XL-array)communications can significantly improve the transmission rate,spectral efficiency,and spatial resolution,and has great potential in next-generation mobile communication networks.A crucial problem in XLarray communications is to determine the boundary of applicable regions of the plane wave model(PWM)and spherical wave model(SWM).In this paper,we propose new PWM/SWM demarcations for XL-arrays from the viewpoint of channel gain and rank.Four sets of results are derived for four different array setups.First,an equi-power line is derived for a point-touniform linear array(ULA)scenario,where an inflection point is found at±π6 central incident angles.Second,an equi-power surface is derived for a point-touniform planar array(UPA)scenario,and it is proved that cos2(ϕ)cos2(φ)=12 is a dividing curve,where ϕ andφdenote the elevation and azimuth angles,respectively.Third,an accurate and explicit expression of the equi-rank surface is obtained for a ULA-to-ULA scenario.Finally,an approximated expression of the equirank surface is obtained for a ULA-to-UPA scenario.With the obtained closed-form expressions,the equirank surface for any antenna structure and any angle can be well estimated.Furthermore,the effect of scatterers is also investigated,from which some insights are drawn.展开更多
This study focuses on steeply inclined and extremely thick coal seams(SIETCS)characterized by immense thickness,a steep inclination of coal seams(87°),and high horizontal stress.The geological conditions and mini...This study focuses on steeply inclined and extremely thick coal seams(SIETCS)characterized by immense thickness,a steep inclination of coal seams(87°),and high horizontal stress.The geological conditions and mining technology associated with SIETCS differ significantly from those of generally inclined coal seams,resulting in notable variations in roadway stress distributions.On SIETCS have predominantly examined the impact of rock layers flanking coal seams on rock bursts,with limited emphasis on SIETCS roadways.This study employs comprehensive methods,integrating numerical simulations,theoretical analyses,and field detections to investigate the stress distribution of SIETCS and the mechanisms of rock burst-induced vertical damage,subsequently validated in situ.The vertical stress in SIETCS is minimal,while horizontal stress is concentrated,leading to the formation of layered crack structures(LCS)that distribute above and below the roadways.Additionally,elastic energy significantly concentrates within the LCS.Axial dynamic compressive stress and vertical dynamic tensile stress along the LCS diminish its stability,readily triggering failure.During the LCS failure process,the stored energy is released,converting into kinetic energy required for coal body ejection after reaching the minimum energy for failure and dissipative energy,ultimately leading to rock burst-induced vertical damage in roadways.On-site detection and analysis within SIETCS,along with historical rock burst data,confirm the existence of LCS and its role in inducing vertical rock burst damage.This research establishes essential foundations for preventing rock bursts within SIETCS.展开更多
文摘BACKGROUND The incidence of prostate cancer(PCa)is on the rise in China.The risk level of patients with PCa is associated with disease-free survival rate at 10 years after radical prostatectomy.Predicting prognosis in advance according to the degree of risk can provide a reference for patients,especially treatment options and postoperative adjuvant treatment measures for high-risk/extremely high-risk patients.AIM To explore the predictive value of the prognostic nutritional index(PNI)for biological recurrence in Chinese patients with high/extremely high-risk PCa after radical prostatectomy.METHODS The biochemical test results and clinical data of 193 patients who underwent radical prostatectomy for the first time from January 2015 to December 2020 were retrospectively collected.The PNI value of peripheral blood within 1 wk before surgery was calculated,and during the follow-up period,prostate-specific antigen≥0.2 ng/mL was considered to have biological recurrence.The receiver operating characteristic(ROC)curve was used to calculate the optimal critical value and area under the curve(AUC)of the patients.According to the critical value,the progression-free survival of the high PNI group and low PNI group was compared.The independent influencing factors of the patients’prognosis were obtained by the Cox proportional hazards regression model.RESULTS The non-biological recurrence rates at 1,3,and 5 years were 92.02%,84.05%,and 74.85%,respectively.The optimal critical value for PNI to predict biological recurrence was 46.23,and the AUC was 0.789(95%confidence interval:0.651-0.860;P<0.001).The sensitivity and specificity were 82.93%and 62.30%,respectively.In accordance with the optimal critical value of the ROC curve(46.23),193 patients were further divided into a high PNI group(PNI≤46.23,n=108)and low PNI group(PNI>46.23,n=85).The incidence of postoperative complications in the high PNI group was lower than that in the low PNI group(21.18%vs 38.96%).Kaplan-Meier survival analysis showed that the overall survival rate at 5 years in the low PNI group was 87.96%(13/108),which was lower than that in the high PNI group(61.18%,33/85;P<0.05).Low PNI[hazard ratio(HR)=1.74;P=0.003]and positive incisal margin status(HR=2.14;P=0.001)were independent predictors of biological recurrence in patients with high/extremely high-risk PCa.CONCLUSION The PNI has predictive value for the prognosis of patients with high/extremely high-risk PCa,and is an independent prognostic factor.Patients with low PNI value have a shorter time of nonbiological recurrence after prostatectomy.It is expected that the combined prediction of other clinicopathological data will further improve the accuracy and guide postoperative adjuvant therapy to improve the quality of prognosis.
基金supported by the National Natural Science Foundation of China under Grant No.41821004,the National Key Research and Development Program of China under contract No.2022YFE0140500the National Key R&D Program of China under contract No.2022YFA1004403+2 种基金the Laoshan Laboratory Science and Technology Innovation Project No.LSKJ202202104the National Nature Science Foundation of China No.42130406the Project of Doctoral Found of Qingdao University of Science and Technology under contract No.210010022746.
文摘Three extreme cold events occurred in eastern Asia in January 2016,January 2021,and December 2023.As important factors in atmospheric circulation anomalies,the Blocking High and East Asian Trough(BH-ET)structure played key roles during these three extreme cold wave events.Among these two dynamic patterns,the BH affected the development of the cold waves in two different ways:(1)before the cold waves in 2016 and 2023,the BH pushed the cold air southward,resulting in a slow and gradual cooling,with a cooling rate(CR)in eastern Asia of 1.34℃d^(-1)and 1.2℃d^(-1),respectively,and(2)in January 2021,the sudden collapse of BH caused the cold air to rapidly attack mid-latitude regions,with a CR of 1.87℃d^(-1).In terms of the spatial CR,the temperature drop in 2021 occurred 38.8%and 55%faster than those in 2016 and 2023,respectively.At the same time,the ET influences the wind direction of cold waves by modulating the pressure gradient.Before the cold waves occurred,the meridional wind field near the ET showed negative values,forming northwesterly or northeasterly winds,which continued to affect the southern part of East Asia.The meridional wind in January 2021 was stronger than those in 2016 and 2023,which is thought to be the reason for the strength of the 2021 cold wave.Finally,results from the temperature Empirical Orthogonal Function(EOF)analysis from 1980-2023 verify an obvious BH-ET structure in the three cold wave events,which suggests that this particular climatological state provides a climatic background for the occurrence of cold waves.
基金supported from Science and Technology Development Program of Jilin Province(Nos.20240101128JC,20230402058GH)National Natural Science Foundation of China(No.52130101).
文摘Sodium-ion batteries have emerged as competitive substitutes for low-temperature applications due to severe capacity loss and safety concerns of lithium-ion batteries at−20°C or lower.However,the key capability of ultrafast charging at ultralow temperature for SIBs is rarely reported.Herein,a hybrid of Bi nanoparticles embedded in carbon nanorods is demonstrated as an ideal material to address this issue,which is synthesized via a high temperature shock method.Such a hybrid shows an unprecedented rate performance(237.9 mAh g^(−1) at 2 A g^(−1))at−60℃,outperforming all reported SIB anode materials.Coupled with a Na_(3)V_(2)(PO_(4))_(3)cathode,the energy density of the full cell can reach to 181.9 Wh kg^(−1) at−40°C.Based on this work,a novel strategy of high-rate activation is proposed to enhance performances of Bi-based materials in cryogenic conditions by creating new active sites for interfacial reaction under large current.
基金supported by the National Key Program for Developing Basic Science(Nos.2022YFE0106600 and 2022YFF0801702)the National Natural Science Foundation of China(No.42175060)+1 种基金the Jiangsu Province Science Foundation(No.BK20201259)the support of the Jiangsu Provincial Innovation Center for Climate Change.
文摘East Asia is a region characterized by a typical monsoon climate,which is accompanied by strong precipitation with complex spatiotemporal variability during summer.Previous works have emphasized the impact of tropical signals on extreme summer precipitation over East Asia,but the roles of the mid-high latitude cyclones are still unclear.Using a reanalysis dataset,this study discloses the synergistic influences of anomalous signals from different latitudes on the extreme precipitation event in the Beijing-Tianjin-Hebei(BTH)region during the summer of 2023.The main conclusions are obtained as follows:the decreased sea ice density caused more Arctic cyclones to generate at positions further west in the Barents Sea and the west of the Kara Sea and then move southeast to East Asia in 2023.Furthermore,the synergistic influences of the outward Arctic cyclones and anomalous signals from middle and low latitudes are discussed.First,the significant northward jump of the Western Pacific Subtropical High(WPSH)provid-ed the favorable condition of large-scale background circulation for summer precipitation in the BTH region in 2023.In addition,the southward intrusion of the Arctic cyclones and the mid-latitude zonal wave trains transported massive cold air to the BTH region.Subsequently,the cold air masses met with the warm moist air carried by the landfall typhoon‘Doksuri’,which generated strong fronts and triggered the extreme precipitation on July 29.However,another severe typhoon,‘Kanu’,generated and moved northward from the tropical Pacific,which caused the further northward shift of the WPSH and the termination of this persistent extreme precipitation on August 1.
基金the National Natural Science Foundation of China(62273359)the General Project of Hunan Natural Science Foundation of China(2022JJ30748)the National Major Scientific Research Equipment of China(61927803)。
文摘Blast furnace(BF)burden surface contains the most abundant,intuitive and credible smelting information and acquiring high-definition and high-brightness optical images of which is essential to realize precise material charging control,optimize gas flow distribution and improve ironmaking efficiency.It has been challengeable to obtain high-quality optical burden surface images under high-temperature,high-dust,and extremelydim(less than 0.001 Lux)environment.Based on a novel endoscopic sensing detection idea,a reverse telephoto structure starlight imaging system with large field of view and large aperture is designed.Combined with a water-air dual cooling intelligent self-maintenance protection device and the imaging system,a starlight high-temperature industrial endoscope is developed to obtain clear optical burden surface images stably under the harsh environment.Based on an endoscope imaging area model,a material flow trajectory model and a gas-dust coupling distribution model,an optimal installation position and posture configuration method for the endoscope is proposed,which maximizes the effective imaging area and ensures large-area,safe and stable imaging of the device in a confined space.Industrial experiments and applications indicate that the proposed method obtains clear and reliable large-area optical burden surface images and reveals new BF conditions,providing key data support for green iron smelting.
基金supported by the National Natural Science Foundation of China(Grant Nos.42150204 and 2288101)supported by the China National Postdoctoral Program for Innovative Talents(BX20230045)the China Postdoctoral Science Foundation(2023M730279)。
文摘A nonlinear multi-scale interaction(NMI)model was proposed and developed by the first author for nearly 30 years to represent the evolution of atmospheric blocking.In this review paper,we first review the creation and development of the NMI model and then emphasize that the NMI model represents a new tool for identifying the basic physics of how climate change influences mid-to-high latitude weather extremes.The building of the NMI model took place over three main periods.In the 1990s,a nonlinear Schr?dinger(NLS)equation model was presented to describe atmospheric blocking as a wave packet;however,it could not depict the lifetime(10-20 days)of atmospheric blocking.In the 2000s,we proposed an NMI model of atmospheric blocking in a uniform basic flow by making a scale-separation assumption and deriving an eddyforced NLS equation.This model succeeded in describing the life cycle of atmospheric blocking.In the 2020s,the NMI model was extended to include the impact of a changing climate mainly by altering the basic zonal winds and the magnitude of the meridional background potential vorticity gradient(PVy).Model results show that when PVy is smaller,blocking has a weaker dispersion and a stronger nonlinearity,so blocking can be more persistent and have a larger zonal scale and weaker eastward movement,thus favoring stronger weather extremes.However,when PVy is much smaller and below a critical threshold under much stronger winter Arctic warming of global warming,atmospheric blocking becomes locally less persistent and shows a much stronger westward movement,which acts to inhibit local cold extremes.Such a case does not happen in summer under global warming because PVy fails to fall below the critical threshold.Thus,our theory indicates that global warming can render summer-blocking anticyclones and mid-to-high latitude heatwaves more persistent,intense,and widespread.
基金supported by National Sciences Foundation of China Grants(No.61902158).
文摘This paper expounds upon a novel target detection methodology distinguished by its elevated discriminatory efficacy,specifically tailored for environments characterized by markedly low luminance levels.Conventional methodologies struggle with the challenges posed by luminosity fluctuations,especially in settings characterized by diminished radiance,further exacerbated by the utilization of suboptimal imaging instrumentation.The envisioned approach mandates a departure from the conventional YOLOX model,which exhibits inadequacies in mitigating these challenges.To enhance the efficacy of this approach in low-light conditions,the dehazing algorithm undergoes refinement,effecting a discerning regulation of the transmission rate at the pixel level,reducing it to values below 0.5,thereby resulting in an augmentation of image contrast.Subsequently,the coiflet wavelet transform is employed to discern and isolate high-discriminatory attributes by dismantling low-frequency image attributes and extracting high-frequency attributes across divergent axes.The utilization of CycleGAN serves to elevate the features of low-light imagery across an array of stylistic variances.Advanced computational methodologies are then employed to amalgamate and conflate intricate attributes originating from images characterized by distinct stylistic orientations,thereby augmenting the model’s erudition potential.Empirical validation conducted on the PASCAL VOC and MS COCO 2017 datasets substantiates pronounced advancements.The refined low-light enhancement algorithm yields a discernible 5.9%augmentation in the target detection evaluation index when compared to the original imagery.Mean Average Precision(mAP)undergoes enhancements of 9.45%and 0.052%in low-light visual renditions relative to conventional YOLOX outcomes.The envisaged approach presents a myriad of advantages over prevailing benchmark methodologies in the realm of target detection within environments marked by an acute scarcity of luminosity.
基金Project supported by the National Natural Science Foundation of China(Grant No.12274440)the National Key R&D Program of China(Grant No.2022YFA1403903)the Synergetic Extreme Condition User Facility(SECUF)。
文摘Magnetoresistance(MR)is a pivotal transport phenomenon within the realm of condensed matter physics.In recent years,materials exhibiting extremely large unsaturated magnetoresistance(XMR),which are often potential topological materials,have garnered significant attention.In this study,we synthesized single crystals of ZrBi_(2) and performed electrical and specific heat measurements on them.The resistivity of ZrBi_(2) displays metallic behavior with a high residual resistance ratio.Notably,the MR of ZrBi_(2) reaches approximately 2.0×10^(3)%at 2 K and 16 T without saturation.Weak Shubnikov-de Haas oscillations with two frequencies were observed above 13.5 T,which correspond to 237 T and 663 T.Hall effect fitting yields nearly equal concentrations of electron and hole carriers with concentrations of approximately 10^(21)cm^(-3)and mobilities of approximately 5000 cm^(2)·V^(-1)·s^(-1)at 2 K.The XMR could be attributed to the electron-hole compensation with high mobility.
基金supported by the National Natural Science Foundation of China(No.52174275).
文摘The extreme removal of SiO2 and MnO inclusions in 304 stainless steel in supergravity fields was investigated using an inhouse high-temperature supergravity equipment.The influences of the gravity coefficient and separation time on the removal efficiency of the inclusions were studied.After supergravity treatment,the inclusions migrated to the top of the sample and formed large aggregates.Meanwhile,the lower part of the sample was purified considerably and appeared significantly cleaner than the raw material.At the gravity coefficient of 500 and separation time of 600 s,the total oxygen content at the bottom of the sample(position E)decreased from 240 to 28 ppm.This corresponded to a total oxygen removal rate of 88.33%.The volume fraction and number density of inclusions exhibited a gradient distribution along the supergravity direction,with values of 8.5%and 106 mm^(-2) at the top of the sample(position A)and 0.06%and 22 mm^(-2) at its bottom.
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supported by the National Key Research and Development Program[grant number 2022YFC3004203]the S&T Development Fund of CAMS(Chinese Academy of Meteorological Sciences)[grant numbers 2023KJ040 and 2024KJ013].
文摘Subseasonal forecasting of extreme events is crucial for early warning systems.However,the forecast skills for extreme events are limited.Taking the extreme cold events in January 2018 as a specific example,and analyzing the 34 extreme cold events in East Asia from 1998 to 2020,the authors evaluated the forecast skills of the ECMWF model ensemble members on subseasonal time scales.The results show that while the ensemble mean has limited skills for forecasting extreme cold events at the 3-week lead time,some individual members demonstrate high forecast skills.For most extreme cold events,there are>10%of members among the total ensembles that can well predict the rapid temperature transitions at the 14-day lead time.This highlights the untapped potential of the ECMWF model to forecast extreme cold events on subseasonal time scales.High-skill ensemble members rely on accurate predictions of atmospheric circulation patterns(500-hPa geopotential height,mean sea level pressure)and key weather systems,including the Ural Blocking and Siberian High,that influence extreme cold events.
基金jointly supported by the National Natural Science Foundation of China[grant numbers U2342202 and 42175005]the Qing Lan Project[grant number R2023Q06]。
文摘A numerical simulation was performed using the Thompson microphysics scheme to preliminarily investigate the features of the microphysical processes involved in the record-breaking rainfall event that occurred in Henan Province,China,on 20 July 2021.The simulation results showed that a strong meso-𝛾-scale vortical updraft was concurrent with the torrential rainfall.The main finding is that this event was characterized by typical midlatitude warm-rain processes.The simulation with the Thompson microphysics scheme further indicated that highly efficient collision-coalescence of cloud water to rainwater resulted in a considerably active rain droplet growth,leading to this record-breaking rainfall event.
基金supported by the National Natural Science Foundation of China(Grant Nos.42330610 and 42075010)。
文摘The Sichuan Basin(SCB),China has a high incidence of extremely persistent heavy rainfall(EPHR)events.The EPHR events from 2009 to 2019 in the SCB were mainly concentrated over the northern and northwestern windward slopes and the central basin.They occurred from June to September,but especially in July,and peaked at 0300 LST.ERA5 reanalysis data and objective classification were used to investigate the synoptic patterns and their effects.There were three synoptic patterns during EPHR events,all accompanied by a Southwest Vortex.The location and intensity of the Southwest Vortex,thermal forcing of the Tibetan Plateau(TP),and low-level winds can greatly affect the intensity and spatial distribution of EPHR.When the Southwest Vortex was located in the western SCB and there were southerly low-level jets(LLJs),convergence and upslope wind would lead to EPHR over the northwestern or northern windward slopes.If there was no LLJ and the whole SCB was under the center of the Southwest Vortex,nocturnal EPHR was controlled by the internal circulation of the Southwest Vortex and the updraft generated by the thermal forcing of the TP,and the rainfall was weaker.The southeastern entrance of the SCB was a key area where the low-level wind dominated the nocturnal peak of EPHR.The nocturnal strengthened southeasterly wind in the key area is attributable to inertial oscillation,and the topographic friction plays an essential role in transporting momentum and moisture into the basin by generating easterly and northeasterly ageostrophic winds.
基金supported by the Reliability Improvement Technology and Application of Epoxy Impregnated Paper Bushing in Extreme Environments under granted DQ30DK24001P.
文摘In Xinjiang,China,Oil-immersed paper bushings used in reactors are highly susceptible to discharge breakdown faults due to drastic fluctuations in environmental and oil temperatures.To mitigate this problem,oil-free and explosion-proof epoxy resin-impregnated paper(ERIP)bushings are recommended as replacements.This study develops a multi-physics(electric-thermal-fluid)coupling model for 750 kV high voltage reactors ERIP bushings.The model aims to comprehensively assess their thermal and electrical performance under extreme ambient temperatures ranging from−40℃ to 90℃ and oil temperatures varying from−10℃ to 90℃.The results demonstrate that the bushing temperature rises consistently with increases in ambient temperature.Additionally,the location of the hottest point on the conductive rod exhibits an upward shift as the ambient temperature climbs.Significantly,when a temperature difference exists between the oil and the external environment,this upward movement remains relatively constrained.Even when the external temperature increases from−40℃ to 80℃,the hottest point shifts upward only 2457 mm.Conversely,in the absence of a temperature difference between the oil and external environment,a modest 10℃ increase in ambient temperature(from 80℃ to 90℃)triggers a substantial 11,356 mm upward displacement of the hottest point.Moreover,this study reveals that the electric field distribution within the bushings remains largely unaffected by environmental temperature changes.
基金supported by the National Natural Science Foundation of China (Grant Nos.42005029 and 41701103)the China Meteorological Administration Special Foundation for Innovation and Development (Grant No.CXFZ2024Q007)。
文摘In the summer of 2024, following a strong El Ni?o event in the preceding winter, the tropical Indian Ocean and tropical North Atlantic recorded their highest SSTs since 1961, along with a significant westward shift and intensification of the western Pacific subtropical high(WPSH). Under these conditions, China experienced its hottest summer since 1961,and was hit by a series of high-impact extreme weather and climate events. From 9 June to 2 July, southern China experienced an unprecedented extreme precipitation event that exceeded the well-known 1998 summer precipitation event in both duration and impact scope, resulting in devastating floods in the Yangtze River basin. Subsequently, in early to midJuly, the Huanghe-Huaihe Basin suffered from a severe drought–flood abrupt alternation event, heavily affecting Henan and Shandong. Meanwhile, southern China underwent a widespread heatwave event lasting 74 days, ranking as the second most intense since 1961. From late July to the end of August, northern China faced unusually frequent heavy precipitation events, with cumulative precipitation reaching the second highest for the same period since 1961, causing floods in many rivers of northern China. This study provides a timely summary and assessment of the characteristics and impacts of these extreme events. It serves as a reference for climate change research, including mechanism analysis, numerical simulation,and climate event attribution, and also offers valuable insights for improving meteorological disaster prevention and mitigation strategies.
基金supported by the Natural Science Foundation of China(Grant No:42105025,42075189,42275036,and 42430610)the National Key R&D Program of China under Grant 2021YFA0718000+3 种基金the China Meteorological Administration Youth Innovation Team(CMA2023QN15)China Meteorological Administration Key Innovation Team(CMA2024ZD07)the development fund of South China Sea Institute of Oceanology of the Chinese Academy of Sciences(SCSIO202203 and SCSIO202208)the Open Research Fund of the State Key Laboratory of Tropical Oceanography(South China Sea Institute of Oceanology,Chinese Academy of Sciences)(LTO2110)。
文摘The increase in frequency and intensity of Extreme High-temperature Events(EHEs)over Central-Eastern China(CEC)in recent decades has severely impacted social development and livelihoods.Using observation and reanalysis datasets,this study explores the effect of the East Asian subtropical westerly jet stream(EAJ)on the CEC EHEs for the summers spanning 1979–2020.Considering its general relative location to the right side of the upper-level jet stream exit region,CEC would theoretically suffer more EHEs with a stronger and northwardly-shifted EAJ in summer due to the likelihood of abnormal subsidence induced by the EAJ.However,such an EAJ–EHE connection has been unstable over the past four decades but has displayed an evident interdecadal change.Before the late 1990s,the interannual variation of the EAJ was manifested mainly by its meridional displacement in the northeastern part of East Asia;thus,the atmospheric responses were essentially located to the east of CEC,exerting less of an influence on the CEC EHEs.However,since the late 1990s,the EAJ variation has featured an intensity change in its center over the northwest portion of the CEC,which has resulted in a westward shift in atmospheric responses to cover the CEC region.Therefore,the EAJ could potentially affect the summer CEC EHEs during 2000–21.Our findings offer support for an in-depth understanding of the formation mechanisms of extreme weather/climate events of this nature and thus provide a scientific reference for seasonal climate predictions.
基金Supported by 2024 Central Financial Comprehensive Protection Project for Abies chensiensis(610000242000000026647)2024 Provincial Forestry and Grassland Reform and Development Fund for the National Key Wild Plant Protection Project(610000242000000028574)2024 Biodiversity Conservation Project(610000242000000024911).
文摘The implementation of the ecological protection red line serves as a crucial protective barrier for the conservation of wild plants with extremely small populations by delineating specific geographical areas designated for their conservation.The implementation of a comprehensive set of conservation measures aimed at establishing a biodiversity conservation network for wild plants with extremely small populations has laid the foundation for the health and stability of ecosystems,as well as the harmonious coexistence of humans and the natural environment.Research on the conservation of wild plants with extremely small populations serves as a critical foundation for informing and enhancing the effective conservation of such populations.This paper provides a systematic examination of the theoretical and practical conservation status of certain wild plants with extremely small populations and discusses the conservation trends of these populations within the framework of ecological protection red line delineation.In the future,strategies for the conservation of wild plants with extremely small populations should be integrated with an analysis of the causes of endangerment.This approach will provide a robust foundation for applied research focused on the conservation of these vulnerable plant populations.
基金supported by the National Natural Science Foundation of China(No.52074296)。
文摘In extremely close-distance coal seam(ECDCS)mining,section coal pillars remain after upper coal seam(UCS)extraction.Thus,for layout and support design of lower coal seam(LCS)mining roadways,it is critical to account for UCS goaf deterioration and residual coal pillar(RCP)-induced stress disturbance.Taking the 6.4 m layer spacing of ECDCS mining in Nanyangpo Coal Mine as a case study,this research aimed to determine the optimal layout and surrounding rock control method for the 24202-ventilation roadway in the RCP area.First,the challenges of roadway layout and support under RCP were clarified:three layout methods face distinct RCPinduced stress disturbances and goaf-related roof damage.A finite element model was established;the second invariant of deviatoric stress(J_(2))and horizontal stress index were introduced to analyze plastic zone and stress evolution after UCS mining.Results show that J_(2)distributes symmetrically,with its peak diffusing downward and attenuating in a“/”-shaped pattern.Six schemes were simulated to compare plastic zone distributions at different positions,revealing that the optimal layout consists of a roadway alignment with the RCP center.Based on roadway layout and roof conditions,a cooperative control scheme was proposed:deep,strong anchorage with long cables across the RCP,and shallow stable support with short bolts in the ECDCS.This scheme secures roof cables anchored to the UCS RCP roof to achieve cross-seam anchorage.On-site borehole peeping and loose circle tests confirm smooth surrounding rock hole walls and limited failure range.Specifically,surrounding rock deformation and roof separation were controlled within 200 mm and 80 mm,respectively,with stable bolt/cable support resistance.These results offer an innovative solution for roadway layout design and support strategies under RCP in ECDCS,with significant engineering application value.
基金supported in part by the National Natural Science Foundation of China (NSFC) under Grants 62271310 and 62125108in part by the Fundamental Research Funds for the Central Universities of Chinain part by the NSFC under Grant 62431014
文摘Extremely large-scale array(XL-array)communications can significantly improve the transmission rate,spectral efficiency,and spatial resolution,and has great potential in next-generation mobile communication networks.A crucial problem in XLarray communications is to determine the boundary of applicable regions of the plane wave model(PWM)and spherical wave model(SWM).In this paper,we propose new PWM/SWM demarcations for XL-arrays from the viewpoint of channel gain and rank.Four sets of results are derived for four different array setups.First,an equi-power line is derived for a point-touniform linear array(ULA)scenario,where an inflection point is found at±π6 central incident angles.Second,an equi-power surface is derived for a point-touniform planar array(UPA)scenario,and it is proved that cos2(ϕ)cos2(φ)=12 is a dividing curve,where ϕ andφdenote the elevation and azimuth angles,respectively.Third,an accurate and explicit expression of the equi-rank surface is obtained for a ULA-to-ULA scenario.Finally,an approximated expression of the equirank surface is obtained for a ULA-to-UPA scenario.With the obtained closed-form expressions,the equirank surface for any antenna structure and any angle can be well estimated.Furthermore,the effect of scatterers is also investigated,from which some insights are drawn.
基金support of the National Natural Science Foundation of China(52374180,52327804).
文摘This study focuses on steeply inclined and extremely thick coal seams(SIETCS)characterized by immense thickness,a steep inclination of coal seams(87°),and high horizontal stress.The geological conditions and mining technology associated with SIETCS differ significantly from those of generally inclined coal seams,resulting in notable variations in roadway stress distributions.On SIETCS have predominantly examined the impact of rock layers flanking coal seams on rock bursts,with limited emphasis on SIETCS roadways.This study employs comprehensive methods,integrating numerical simulations,theoretical analyses,and field detections to investigate the stress distribution of SIETCS and the mechanisms of rock burst-induced vertical damage,subsequently validated in situ.The vertical stress in SIETCS is minimal,while horizontal stress is concentrated,leading to the formation of layered crack structures(LCS)that distribute above and below the roadways.Additionally,elastic energy significantly concentrates within the LCS.Axial dynamic compressive stress and vertical dynamic tensile stress along the LCS diminish its stability,readily triggering failure.During the LCS failure process,the stored energy is released,converting into kinetic energy required for coal body ejection after reaching the minimum energy for failure and dissipative energy,ultimately leading to rock burst-induced vertical damage in roadways.On-site detection and analysis within SIETCS,along with historical rock burst data,confirm the existence of LCS and its role in inducing vertical rock burst damage.This research establishes essential foundations for preventing rock bursts within SIETCS.
