The connection of phytoplankton biomass in the Marguerite Bay polynya of the western Antarctic Peninsula to the Southern Annular Mode

Antarctic coastal polynyas are biological hotspots in the Southern Ocean that support the abundance of hightrophic-level predators and are important for carbon cycling in the high-latitude oceans.In this study,we examined the interannual variation of summertime phytoplankton biomass in the Marguerite Bay polynya(MBP)in the western Antarctic Peninsula area,and linked such variability to the Southern Annular Mode(SAM)that dominated the southern hemisphere extratropical climate variability.Combining satellite data,atmosphere reanalysis products and numerical simulations,we found that the interannual variation of summer chlorophyll-a(Chl-a)concentration in the MBP is significantly and negatively correlated with the spring SAM index,and weakly correlated with the summer SAM index.The negative relation between summer Chl-a and spring SAM is due to weaker spring vertical mixing under a more positive SAM condition,which would inhibit the supply of iron from deep layers into the surface euphotic layer.The negative relation between spring mixing and spring SAM results from greater precipitation rate over the MBP region in positive SAM phase,which leads to lower salinity in the ocean surface layer.The coupled physical-biological mechanisms between SAM and phytoplankton biomass revealed in this study is important for us to predict the future variations of phytoplankton biomasses in Antarctic polynyas under climate change.

Slowing down of the summer Southern Hemisphere Annular Mode trend against the background of ozone recovery

20世纪末期,南半球热带外地区经历了显著的气候变化,包括夏季南半球环状模(SAM)的显著上升趋势,伴随着南极半岛的增暖和别林斯高晋海的海冰融化.这些趋势主要是由20世纪末期南极平流层臭氧消耗所驱动的.本文发现,自2001年左右以来,在南极平流层臭氧恢复的背景下,观测到的夏季SAM的上升趋势已经趋于平缓,验证了前人利用数值模拟预测的夏季SAM上升趋势减缓现象,与SAM在臭氧恢复后趋势只减缓但没有逆转不同,南极地表气温和海冰的趋势发生了逆转.南极半岛由变暖趋势转为降温趋势,别林斯高晋海域的海冰由融化趋势转为增多趋势.

Mass transfer mechanism and relationship of gas–liquid annular flow in a microfluidic cross-junction device

Mass transfer performance of gas–liquid two-phase flow at microscale is the basis of application of microreactor in gas–liquid reaction systems.At present,few researches on the mass transfer property of annular flow have been reported.Therefore,the mass transfer mechanism and relationship of gas–liquid annular flow in a microfluidic cross-junction device are studied in the present study.We find that the main factors,i.e.,flow pattern,liquid film thickness,liquid hydraulic retention time,phase interface fluctuation,and gas flow vorticity,which influence the flow mass transfer property,are directly affected both by gas and liquid flow velocities.But the influences of gas and liquid velocities on different mass transfer influencing factors are different.Thereout,the fitting relationships between gas and liquid flow velocities and mass transfer influencing factors are established.By comparing the results from calculations using fitting equations and simulations,it shows that the fitting equations have relatively high degrees of accuracy.Finally,the Pareto front,namely the Pareto optimal solution set,of gas and liquid velocity conditions for the best flow mass transfer property is obtained using the method of multi-objective particle swarm optimization.It is proved that the mass transfer property of the gas–liquid two-phase flow can be obviously enhanced under the guidance of the obtained Pareto optimal solution set through experimental verification.

Optimal Design of Aperture Illuminations for Microwave Power Transmission with Annular Collection Areas

This work presents an optimal design method of antenna aperture illumination for microwave power transmission with an annular collection area.The objective is to maximize the ratio of the power radiated on the annular collection area to the total transmitted power.By formulating the aperture amplitude distribution through a summation of a special set of series,the optimal design problem can be reduced to finding the maximum ratio of two real quadratic forms.Based on the theory of matrices,the solution to the formulated optimization problem is to determine the largest characteristic value and its associated characteristic vector.To meet security requirements,the peak radiation levels outside the receiving area are considered to be extra constraints.A hybrid grey wolf optimizer and Nelder–Mead simplex method is developed to deal with this constrained optimization problem.In order to demonstrate the effectiveness of the proposed method,numerical experiments on continuous apertures are conducted;then,discrete arrays of isotropic elements are employed to validate the correctness of the optimized results.Finally,patch arrays are adopted to further verify the validity of the proposed method.

Mechanical properties and microstructural evolution of rheocast A356 semi-solid slurry prepared by annular electromagnetic stirring

Nowadays,having an effective technique in preparing semi-solid slurries for rheocasting process seems to be an essential requirement.In this study,semi-solid slurry of A356 aluminum alloy was prepared by three-phase annular electromagnetic stirring(A-EMS)technique under different conditions.The effects of stirring current,pouring temperature and stirring time on microstructural evolution,mean particle size,shape factor and solid fraction were investigated.The rheocasting process was carried out by using a drop weight setup and to inject the prepared semi-solid slurry in optimal conditions into the step-die cavity.The filling behavior and mechanical properties of parts were studied.Microstructural evolution showed that the best semi-solid slurry which had fine spherical particles with the average size of~27μm and a shape factor of~0.8 was achieved at the stirring current of 70 A,melt pouring temperature of 670℃,and stirring time of 30 s.Under these conditions,the step-die cavity was completely filled at die preheating temperature of 470℃.The hardness increases by decreasing step thickness as well as die preheating temperature.Moreover,the tensile properties are improved at lower die preheating temperatures.The fracture surface,which consists of a complex topography,indicates a typical ductile fracture.

Generalized granuloma annulare in an infant clinically manifested as papules and atrophic macules:A case report

BACKGROUND Granuloma annulare(GA)has diverse clinical manifestations including papules,plaques,and nodules on the extremities that are skin-colored,pink,or purple.Approximately 15%of all GA cases are considered generalized GA.CASE SUMMARY Herein,we describe the case of a pediatric patient who initially presented with papules and later developed generalized atrophic macules.Upon examination,two different morphologic lesions were histopathologically confirmed:Epithelioid nodular GA and scattered histiocytic infiltrative GA.This patient exhibited rare clinical manifestations that differed throughout the course of the disease.The varying histopathological types and clinical manifestations of GA may be linked to the different stages of the disease.CONCLUSION This rare case demonstrates the different histopathological features of different stages and clinical manifestations of granuloma annulare in an infant.

Elastic fiber degradation in the development of pediatric granuloma annulare:Report of 39 cases

BACKGROUND Granuloma annulare(GA)has diverse clinical manifestations,multiple subtypes,and unknown etiology and pathogenesis.Existing studies regarding GA in children are scarce.AIM To examine the correlation between clinical manifestation and histopathology of pediatric GA.METHODS A total of 39 patients under 18 years of age with both a clinical and pathological diagnosis of GA at Kunming Children's Hospital from 2017 to 2022 were retrieved.Their medical records were consulted,and clinical data of the children were recorded and summarized,including gender,age,disease site,etc.Existing wax blocks of skin lesion specimens of children and pathological films were retrieved for further study and relevant histology,including hematoxylin-eosin,Alcian blue,elastic fiber(Victoria blue-Lichon red method),and antacid staining.Finally,the children’s clinical manifestations,histopathological results,and special staining characteristics were analyzed.RESULTS The clinical manifestations of granuloma annulare in children were diverse:11 cases presented with a single lesion,25 with multiple lesions,and 3 with generalized lesions.The pathological typing comprised histiocytic infiltration,palisading granuloma,epithelioid nodular,and mixed types in 4,11,9,and 15 cases,respectively.Thirty-nine cases were negative for antacid staining.The positive rate of Alcian blue staining was 92.3%,and that of elastic fiber staining was 100%.The degree of elastic fiber dissolution and granuloma annulare histopathological typing were positively correlated(r=0.432,P<0.05).No correlation was found between clinical presentation and histopathological typing of the granuloma annulare in children.In the pathological diagnosis of granuloma annulare,the positive elastic fiber staining rate was higher than that of Alcian blue staining.A correlation was found between elastic fiber dissolution degree and histopathological staging.However,the differences in pathological staging may have been related to the pathological manifestation of granuloma annulare at different periods.CONCLUSION Elastic fiber degradation may be a critical step in the pathogenesis of pediatric granuloma annulare.This is also one of the first studies focused on granuloma annulare in children.

Scanning transmission electron microscopy: A review of high angle annular dark field and annular bright field imaging and applications in lithium-ion batteries

Scanning transmission electron microscopy（STEM） has been shown as powerful tools for material characterization,especially after the appearance of aberration-corrector which greatly enhances the resolution of STEM. High angle annular dark field（HAADF） and annular bright field（ABF） imaging of the aberration-corrected STEM are widely used due to their high-resolution capabilities and easily interpretable image contrasts. However, HAADF mode of the STEM is still limited in detecting light elements due to the weak electron-scattering power. ABF mode of the STEM could detect light and heavy elements simultaneously, providing unprecedented opportunities for probing unknown structures of materials. Atomiclevel structure investigation of materials has been achieved by means of these imaging modes, which is invaluable in many fields for either improving properties of materials or developing new materials. This paper aims to provide a introduction of HAADF and ABF imaging techniques and reviews their applications in characterization of cathode materials, study of electrochemical reaction mechanisms, and exploring the effective design of lithium-ion batteries（LIBs）. The future prospects of the STEM are also discussed.

应用生物扰动实验系统(Annular Flux System)研究双壳类生物沉降作用

利用不锈钢环形采泥器 ,在胶州湾潮间带沿天然断面选取典型站位 ,现场采取无扰动沉积物样品 ,应用生物扰动实验系统 (Annular Flux System) ,选用菲律宾蛤仔 (Ruditapes philippinarum)和缢蛏 (Sinonovacula constricta) ,在实验室内进行实验。结果表明 :菲律宾蛤仔个体的生物沉降率平均为 0 .15g/ m2 · h· ind,平均净生物沉降率为自然颗粒沉降率的 3.0 5倍 ;缢蛏个体的生物沉降率平均为 0 .2 9g/ m2·h· ind,平均净生物沉降率为自然颗粒沉降率的 2 .6 3倍。

Distribution characteristics of dissolved organic carbon in annular wetland soil-water solutions through soil profiles in the Sanjiang Plain,Northeast China

Overwhelming evidence reveals that concentrations of dissolved organic carbon （DOC） have increased in streams which brings negative environmental impacts. DOC in stream flow is mainly originated from soil-water solutions of watershed. Wetlands prove to be the most sensitive areas as an important DOC reserve between terrestrial and fluvial biogeosystems. This reported study was focused on the distribution characteristics and the controlling factors of DOC in soil-water solutions of annular wetland, i.e., a dishing wetland and a forest wetland together, in the Sanjiang Plain, Northeast China. The results indicate that DOC concentrations in soilwater solutions decreased and then increased with increasing soil depth in the annular wetland. In the upper soil layers of 0-10 cm and 10-20 cm, DOC concentrations in soil-water solutions linearly increased from edge to center of the annular wetland （R^2 = 0.3122 and R^2 = 0.443）. The distribution variations were intimately linked to DOC production and utilization and DOC transport processes in annular wetland soil-water solutions. The concentrations of total organic carbon （TOC）, total carbon （TC） and Fe（II）, DOC mobility and continuous vertical and lateral flow affectext the distribution variations of DOC in soil-water solutions. The correlation coefficients between DOC concentrations and TOC, TC and Fe（II） were 0.974, 0.813 and 0.753 respectively. These distribution characteristics suggested a systematic response of the distribution variations of DOC in annular wetland soil-water solutions to the geometry of closed depressions on a scale of small catchments. However, the DOC in soil pore water of the annular wetland may be the potential source of DOC to stream flow on watershed scale. These observations also implied the fragmentation of wetland landscape could bring the spatial-temporal variations of DOC distribution and exports, which would bring negative environmental impacts in watersheds of the Sanjiang Plain.

Annular multiphase flow behavior during deep water drilling and the effect of hydrate phase transition

It is very important to understand the annular multiphase flow behavior and the effect of hydrate phase transition during deep water drilling. The basic hydrodynamic models, including mass, momentum, and energy conservation equations, were established for annular flow with gas hydrate phase transition during gas kick. The behavior of annular multiphase flow with hydrate phase transition was investigated by analyzing the hydrate-forming region, the gas fraction in the fluid flowing in the annulus, pit gain, bottom hole pressure, and shut-in casing pressure. The simulation shows that it is possible to move the hydrate-forming region away from sea floor by increasing the circulation rate. The decrease in gas volume fraction in the annulus due to hydrate formation reduces pit gain, which can delay the detection of well kick and increase the risk of hydrate plugging in lines. Caution is needed when a well is monitored for gas kick at a relatively low gas production rate, because the possibility of hydrate presence is much greater than that at a relatively high production rate. The shut-in casing pressure cannot reflect the gas kick due to hydrate formation, which increases with time.

Annular electromagnetic stirring——a new method for the production of semi-solid A357 aluminum alloy slurry

A new method for producing semisolid slurry, annular electromagnetic stirring （AEMS）, to refine and spheroidize grains was exploited. Experimental work was undertaken to investigate the effects of cooling rate, stirring power and stirring time on the solidification behavior of A357 alloy using A-EMS. It was found that increasing the cooling rate and stirring power gave rise to substantial grain refinement, which could be attributed to the increase of effective nucleation rate caused by the extremely uniform temperature and composition fields in the bulk liquid during the initial stage of solidification. Results showed that a fully grain refined spherical structure could be obtained using proper processing conditions within 10 s.

The Springtime North Asia Cyclone Activity Index and the Southern Annular Mode

The relationship between the North Asia cyclone （NAC） activity and the Southern Annular Mode （SAM） is documented in this research. The definition of the NAC index （NACI） is based on the atmospheric relative vorticity in North Asia. The analysis yields a significant positive correlation between previous winter Southern Annular Mode index （SAMI） and spring NACI in the interannual variability, with a correlation coefficient of 0.51 during 1948-2000. Analysis of the NAC-related and SAM-related atmospheric general circulation variability demonstrates such a relationship. The study further reveals that when the winter SAM becomes strong, the springtime atmospheric convection in tropical western Pacific will intensify and the local Hadley circulation will be strengthened. As a result, the abnormal subsiding motion over South China makes the temperature gradient intensified in the low level and strengthens the jet in the high level, both of which are beneficial to the development of NAC activity.

Numerical Investigation on the Influence of Nozzle Lip Thickness on the Flow Field and Performance of an Annular Jet Pump

The performance of an annular jet pump( AJP) is determined by its area ratio A( ratio of cross sectional area of throat and annular nozzle) and flow rate ratio q( ratio of primary and secondary flow rate,Qs/Qj),while the nozzle lip thickness is neglected in the present studies. This paper presents a study on the effect of the thickness on the flow field and performance of an AJP with A = 1. 75. With the increasing flow rate ratio and nozzle lip thickness,a small vortex forms at the nozzle lip and keeps on growing. However,as the flow rate ratio or nozzle lip thickness is extremely low,the vortex at the lip vanishes thoroughly. Moreover,the recirculation width varies conversely with the nozzle lip thickness when the flow rate ratio q ≤ 0. 13. While the deviation of the recirculation width with different nozzle lip thickness is negligible with q ≥ 0. 13. Additionally the existence of nozzle lip hinders the momentum exchange between the primary and secondary flow and leads to a mutation of velocity gradient near the nozzle exit,which shift the recirculation downstream. Finally,based on the numerical results of the streamwise and spanwise vortex distributions in the suction chamber, the characteristics of the mixing process and the main factors accounting for the AJP performance are clarified.

Comparisons of microstructure homogeneity,texture and mechanical properties of AZ80 magnesium alloy fabricated by annular channel angular extrusion and backward extrusion

This paper provided an efficient single pass severe plastic deformation(SPD)method,annular channel angular extrusion(ACAE),for fabricating AZ80 magnesium alloy shell part.The effect of ACAE process on the microstructure homogeneity,texture,and mechanical properties of extruded part was experimentally investigated.For comparison,conventional backward extrusion(BE)was also conducted on processing AZ80 part with same specification.The results showed that ACAE process has a better capacity to refine the microstructure and dramatic improve the deformation homogeneity of the extruded part than BE process.Due to two strong shear deformations were implemented,ACAE process could also concurrently modify the basal texture more notably than BE process.In particular,a bimodal texture was found in ACAE extruded part,which was greatly related to the enhanced synergetic action of basal slip and secondary<c+a>slip caused by the effective shear stress.More uniform and superior hardness along the thickness and height of part were achieved via ACAE process.Further surveying of tensile tests also showed that the part fabricated by ACAE process exhibited significantly higher and far more homogeneous tensile properties with an excellent balance of strength and ductility.The remarkable enhanced tensile properties of ACAE extruded part could be primarily attributed to the significant grain refinement,which provided a powerful grain boundary strengthening effect and meaningfully suppressed the development of twin-sized cracks during tensile deformation.It was established that ACAE process seemed to be a very promising single pass SPD method for manufacturing Mg-based alloy shell parts with more homogeneous microstructure and superior performance.

AXISYMMETRIC BENDING OF TWO-DIRECTIONAL FUNCTIONALLY GRADED CIRCULAR AND ANNULAR PLATES

Assuming the material properties varying with an exponential law both in the thick- ness and radial directions, axisymmetric bending of two-directional functionally graded circular and annular plates is studied using the semi-analytical numerical method in this paper. The deflections and stresses of the plates are presented. Numerical results show the well accuracy and convergence of the method. Compared with the finite element method, the semi-analytical nu- merical method is with great advantage in the computational efficiency. Moreover, study on ax- isymmetric bending of two-directional functionally graded annular plate shows that such plates have better performance than those made of isotropic homogeneous materials or one-directional functionally graded materials. Two-directional functionally graded material is a potential alternative to the one-directional functionally graded material. And the integrated design of materials and structures can really be achieved in two-directional functionally graded materials.

Numerical and experimental research on annular crossed cable-truss structure under cable rupture

The Annular Crossed Cable-Truss Structure（ACCTS） is a new type of Tensile Spatial Structure with a configuration suitable to cover large-span stadiums. Its configuration has potential to perform well in resisting disproportionate collapse. However, its disproportionate collapse resistance hasn＇t yet been analyzed in depth. In this study, numerical and experimental research was carried out to investigate the performance of ACCTS under cable rupture. The numerical analysis was done for ten cable-rupture plans using LS-DYNA（explicit method） and the experimental test on an ACCTS with a diameter of 17.15 m was performed for three cable-rupture plans. It is concluded that, while deflections increase with the number of removed cables, an ACCTS does not undergo a disproportionate collapse and it provides a promising structural concept for tensile spatial structures.

Hydrodynamic characteristics of 30%TBP/kerosene-HNO3 solution system in an annular centrifugal contactor

Annular centrifugal contactors (ACCs) have many advantages and are recognized as key solvent-extraction equipment for the future reprocessing of spent nuclear fuel (RSNF). To successfully design and operate ACCs for RSNF, it is necessary to understand the hydrodynamic characteristics of the extraction systems in ACCs. The phase ratio (R = Vaq/Vorg, A/O) and liquid holdup volume (V) of the ACC are important hydrodynamic characteristics. In this study, a liquid-fast-separation method was used to systematically investigate the effects of the operational and structural parameters on the V and R (A/O) of a φ20 ACC by using a 30%TBP/kerosene- HNO3 solution system. The results showed that the operational and structural parameters had different effects on the V and R (A/O) of the mixing and separating zones of the ACC, respectively. For the most frequently used structural parameters of the φ20 ACC, when the rotor speed was 3500 r/min, the total flow rate was 2.0 L/h, and the flow ratio (A/O) was 1, the liquid holdup volumes in the mixing zone and rotor were 8.03 and 14.0 mL, respectively, and the phase ratios (A/O) of the mixing zone and separating zone were 0.96 and 1.43, respectively.

Influence of the Preceding Austral Summer Southern Hemisphere Annular Mode on the Amplitude of ENSO Decay

There is increasing evidence of the possible role of extratropical forcing in the evolution of ENSO. The Southern Hemi- sphere Annular Mode （SAM） is the dominant mode of atmospheric circulation in the Southern Hemisphere extratropics. This study shows that the austral summer （December-January-February; DJF） SAM may also influence the amplitude of ENSO decay during austral autumn （March-April-May; MAM）. The mechanisms associated with this SAM-ENSO relationship can be briefly summarized as follows： The SAM is positively （negatively） correlated with SST in the Southern Hemisphere middle （high） latitudes. This dipole-like SST anomaly pattern is referred to as the Southern Ocean Dipole （SOD）. The DJF SOD, caused by the DJF SAM, could persist until MAM and then influence atmospheric circulation, including trade winds, over the Nifio3.4 area. Anomalous trade winds and SST anomalies over the Nifio3.4 area related to the DJF SAM are further developed through the Bjerkness feedback, which eventually results in a cooling （warming） over the Nifio3.4 area followed by the positive （negative） DJF SAM.

Annular pancreas associated with duodenal carcinoma

Annular pancreas (AP) is a rare congenital anomaly. Coexisting malignancy has been reported only in a few cases. We report what is, to the best of our knowledge, the first case in the English literature of duodenal adenocarcinoma in a patient with AP. In a 55-year old woman with duodenal outlet stenosis magnetic resonance cholangiopancreatography showed an aberrant pancreatic duct encircling the duodenum. Duodenojejunostomy was performed. Eight weeks later she presented with painless jaundice. Duodenopancreatectomy revealed a duodenal adenocarcinoma, surrounded by an incomplete AP. Thus, co-existent malignancy with AP can be present without obstructive jaundice and without being visible through preoperative diagnostics.