The carrier transport layer with reflection reduction morphology has attracted extensive attention for improving the utilization of light.Herein,we introduced single-layer hollow ZnO hemisphere arrays(ZHAs)behaving li...The carrier transport layer with reflection reduction morphology has attracted extensive attention for improving the utilization of light.Herein,we introduced single-layer hollow ZnO hemisphere arrays(ZHAs)behaving light trapping effect as the electron transport layer in perovskite photodetectors(PDs).The singlelayer hollow ZHAs can not only reduce the reflection,but also widen the angle of the effective incident light and especially transfer the distribution of the optical field from the ZnO/FTO interface to the perovskite active layer confirmed by the 3D finitedifference time-domain simulation.These merits benefit for the generation,transport and separation of carriers,improving the light utilization efficiency.Finally,our optimized FTO/ZHA/CsPbBr3/carbon structure PDs showed high self-powered performance with a linear dynamic range of 120.3 dB,a detectivity of 4.2×10^(12) Jones,rise/fall time of 13/28μs and the f_(−3) dB of up to 28 kHz.Benefiting from the high device performance,the PD was demonstrated to the application in the directional transmission of encrypted files as the signal receiving port with super high accuracy.This work uniquely utilizes the features of high-performance self-powered perovskite PDs in optical communication,paving the path to wide applications of all-inorganic perovskite PDs.展开更多
Cerebral ischemia not only causes pathological changes in the ischemic areas but also induces a series of secondary changes in more distal brain regions（such as the contralateral cerebral hemisphere）. The impact of ...Cerebral ischemia not only causes pathological changes in the ischemic areas but also induces a series of secondary changes in more distal brain regions（such as the contralateral cerebral hemisphere）. The impact of supratentorial lesions, which are the most common type of lesion, on the contralateral cerebellum has been studied in patients by positron emission tomography, single photon emission computed tomography, magnetic resonance imaging and diffusion tensor imaging. In the present study, we investigated metabolite changes in the contralateral cerebral hemisphere after supratentorial unilateral ischemia using nuclear magnetic resonance spectroscopy-based metabonomics. The permanent middle cerebral artery occlusion model of ischemic stroke was established in rats. Rats were randomly divided into the middle cerebral artery occlusion 1-, 3-, 9-and 24-hour groups and the sham group. ~1H nuclear magnetic resonance spectroscopy was used to detect metabolites in the left and right cerebral hemispheres. Compared with the sham group, the concentrations of lactate, alanine, γ-aminobutyric acid, choline and glycine in the ischemic cerebral hemisphere were increased in the acute stage, while the concentrations of N-acetyl aspartate, creatinine, glutamate and aspartate were decreased. This demonstrates that there is an upregulation of anaerobic glycolysis（shown by the increase in lactate）, a perturbation of choline metabolism（suggested by the increase in choline）, neuronal cell damage（shown by the decrease in N-acetyl aspartate） and neurotransmitter imbalance（evidenced by the increase in γ-aminobutyric acid and glycine and by the decrease in glutamate and aspartate） in the acute stage of cerebral ischemia. In the contralateral hemisphere, the concentrations of lactate, alanine, glycine, choline and aspartate were increased, while the concentrations of γ-aminobutyric acid, glutamate and creatinine were decreased. This suggests that there is a difference in the metabolite changes induced by ischemic injury in the contralateral and ipsilateral cerebral hemispheres. Our findings demonstrate the presence of characteristic changes in metabolites in the contralateral hemisphere and suggest that they are most likely caused by metabolic changes in the ischemic hemisphere.展开更多
The emissions of biophotons have been considered a ubiquitous property of living systems and their components. We measured the “spontaneous” photon emissions from fixed whole and sectioned human brains within hyper-...The emissions of biophotons have been considered a ubiquitous property of living systems and their components. We measured the “spontaneous” photon emissions from fixed whole and sectioned human brains within hyper-dark settings. Significant differences in photon counts were measured from different spatial planes. The flux densities were in the order of 2 × 10<sup>-12</sup> W per m<sup>2</sup>. The right hemispheres but not the left hemispheres displayed more photon emissions whose spectral power density profiles exhibited a conspicuous amplitude peak between 7.9 and 8 Hz. Brains measured in the hyperdark (~10<sup>-12</sup> W·m<sup>2</sup>) after removal from the typical lighting of the laboratory emitted more photons than those that had been maintained in the hyperdark for one week. The significant correlation between the numbers of photons emitted from the left hemisphere (but not the right) and global geomagnetic activity also exhibited energy equivalence between the photon flux densities and the geomagnetic shift within the cerebral volumes. These results indicate that what has been assumed to be fixed unresponsive human brain tissue still emits small numbers of photons that may be residuals from ambient light and can potentially interact with global geomagnetic activity. The medical implications for post-mortem intrinsic photonic information based upon the anisotropic microstructures within the hemispheres of the human cerebrum are discussed.展开更多
Natural convection heat transfer in open or closed cavities takes place in different engineering areas. The hemispherical cavity is a part of basic geometries although it is not widely studied. The present paper repor...Natural convection heat transfer in open or closed cavities takes place in different engineering areas. The hemispherical cavity is a part of basic geometries although it is not widely studied. The present paper reports the numerical study of natural convection in a closed hemispherical annulus delimited by two vertically eccentric hemispheres filled with Newtonian fluid (air in this case with <em>Pr</em> = 0.7) is conducted. The inner hemisphere is heated by a heat flux of constant density and the outer one is maintained isothermal. Based on the Boussinesq assumptions, the governing equations are numerically studied using unsteady natural convection formulated with vorticity and stream-function variables. These equations are written by using bispherical coordinates system and solved by using a finite difference method. The effect of the control parameters such as the Rayleigh number (<span style="white-space:nowrap;">10<sup>3</sup> ≤ <em>Ra</em> ≤ 10<sup>6</sup></span>) or the eccentricity (<em>e</em> = ±0.2, ±0.5, 0) in the dynamic and thermal behaviours of the fluid is investigated.展开更多
This study aimed to restore the ultimate strength of dented stainless-steel hemispheres with a radius of 90 mm and a thickness of 0.86 mm.All of the hemispheres were subjected to external hydrostatic pressure.Small st...This study aimed to restore the ultimate strength of dented stainless-steel hemispheres with a radius of 90 mm and a thickness of 0.86 mm.All of the hemispheres were subjected to external hydrostatic pressure.Small stainless-steel stiffened caps were used to eliminate the effect of indention on the ultimate strength.These caps had a radius of 36 mm,a thickness of 0.76 mm,and a height of 10.44 mm.Six hemispherical samples,including two intact hemispheres,two dented hemispheres without stiffening,and two dented hemispheres with stiffening,were prepared.Each hemi-sphere was geometrically measured for shape and thickness,hydrostatically tested for destruction,and numerically evaluated for comparison.The experimental and numerical data agreed well with each other.As a result,a spherical cap can effectively restore the ultimate strength of dented hemispheres under external hydrostatic pressure.The proposed restoration approach can be used to strengthen underwater pressure hulls with large local geometric imperfections.展开更多
By employing the singular value decomposition(SVD) analysis, we have investigated in the present paper the covariations between circulation changes in the Northern(NH) and Southern Hemispheres(SH) and their associatio...By employing the singular value decomposition(SVD) analysis, we have investigated in the present paper the covariations between circulation changes in the Northern(NH) and Southern Hemispheres(SH) and their associations with ENSO by using the NCEP/NCAR reanalysis, the reconstructed monthly NOAA SST, and CMAP precipitation along with NOAA Climate Prediction Center(CPC) ENSO indices. A bi-hemispheric covariation mode(hereafter BHCM) is explored, which is well represented by the first mode of the SVD analysis of sea surface pressure anomaly(SLPA-SVD1). This SVD mode can explain 57.36% of the total covariance of SLPA. BHCM varies in time with a long-term trend and periodicities of 3—5 years. The long term trend revealed by SVD1 shows that the SLP increases in the equatorial central and eastern Pacific but decreases in the western Pacific and tropical Indian Ocean, which facilitates easterlies in the lower troposphere to be intensified and El Ni觡o events to occur with lower frequency. The spatial pattern of the BHCM looks roughly symmetric about the equator in the tropics, whereas it is characterized by zonal disturbances in the mid-latitude of NH and is highly associated with AAO in the mid-latitude of SH. On inter-annual time scales, the BHCM is highly correlated with ENSO. The atmosphere in both the NH and SH responds to sea surface temperature anomalies in the equatorial region, while the contemporaneous circulation changes in the NH and SH in turn affect the occurrence of El Ni觡o/La Ni觡a. In boreal winter, significant temperature and precipitation anomalies associated with the BHCM are found worldwide. Specifically, in the positive phase of the BHCM,temperature and precipitation are anomalously low in eastern China and some other regions of East Asia. These results are helpful for us to better understand interactions between circulations in the NH and SH and the dynamical mechanisms behind these interactions.展开更多
BACKGROUND： Certain neural functions, such as peripheral reflexes, differ between genders, while higher brain functions, such as language, are asymmetrically distributed between the two hemispheres. The question rema...BACKGROUND： Certain neural functions, such as peripheral reflexes, differ between genders, while higher brain functions, such as language, are asymmetrically distributed between the two hemispheres. The question remains as to whether depth perception differs between hemispheric laterality and genders, and whether it is affected by eye dominance. OBJECTIVE： To determine whether depth perception is influenced by factors such as gender, eye dominance, and hemispheric lateralization by recording evoked potential associated with depth perception. DESIGN, TIME AND SETTING： A contrast observation based on neuroelectrophysiology was performed at the Department of Biophysics of Ege University Medical School between June 2006 and April 2007. PARTICIPANTS： A total of 34 subjects, 19 females and 15 males, were included in the study with a mean age of （31.0 ± 6.9） years. All subjects were free of neurological or psychological disorders, or problems such as strabismus or vision correction. METHODS： Random-dot stereograms were used to elicit brain activity. A specially designed signal acquisition system employing two computers was used to record evoked potentials from both hemispheres via two pairs of scalp electrodes placed over the occipitotemporal areas of both hemispheres at symmetrical locations. MAIN OUTCOME MEASURES： Negative potential with a mean latency of （211.21 ±25.55） ms and a mean amplitude of （6.05 ± 1.53） pV was recorded from both occipitotemporal areas in 30 out of 34 participants. This was termed ＂Nd＂ and represented the evoked potential associated with depth perception. RESULTS： There were no significant differences in Nd amplitude or latency between the two hemispheres, the two eyes, or genders （P 〉 0.05）. CONCLUSION： The evoked potential associated with depth perception was not influenced by gender, hemisphere, or eye dominance.展开更多
This paper focusses on steel-welded hemispherical shells subjected to external hydrostatic pressure.The experimental and numerical investigations were performed to study their failure behaviour.The model was fabricate...This paper focusses on steel-welded hemispherical shells subjected to external hydrostatic pressure.The experimental and numerical investigations were performed to study their failure behaviour.The model was fabricated from mild steel and made through press forming and welding.We therefore considered the effect of initial shape imperfection,variation of thickness and residual stress obtained from the actual structures.Four hemisphere models designed with R/t from 50 to 130 were tested until failure.Prior to the test,the actual geometric imperfection and shell thickness were carefully measured.The comparisons of available design codes(PD 5500,ABS,DNV-GL)in calculating the collapse pressure were also highlighted against the available published test data on steel-welded hemispheres.Furthermore,the nonlinear FE simulations were also conducted to substantiate the ultimate load capacity and plastic deformation of the models that were tested.Parametric dependence of the level of sphericity,varying thickness and residual welding stresses were also numerically considered in the benchmark studies.The structure behaviour from the experiments was used to verify the numerical analysis.In this work,both collapse pressure and failure mode in the numerical model were consistent with the experimental model.展开更多
The subject of natural convection heat transfer is motivated by a wide range of applications in engineering technology. The hemispherical cavity is a part of basic geometries although it is not widely studied. The eff...The subject of natural convection heat transfer is motivated by a wide range of applications in engineering technology. The hemispherical cavity is a part of basic geometries although it is not widely studied. The effect of inclinaison on natural convection fluid motions in the gap between two eccentric hemispheres is numerically studied. The inner hemisphere is subjected to a heat flux of a constant density and the outer one is maintened isothermal. The walls separating the two hemispheres are thermally adiabatic. Equations are formulated with vorticity and stream-functions variables. It is also assumed the fluid incompressible and obeys the approximation of Boussinesq. These equations are written by using bispherical coordinates system and solved by using a finite difference method. The results show the topology of flow is strongly dependent on the inclinaison because the flow can change from a unicellular regime to a multicellular regime by varying the inclination from 0 to π. By increasing the Rayleigh number (10<sup>3</sup><<i>Ra</i><10<sup>7</sup>), the flow intensifies. T<span style="letter-spacing:-0.05pt;">he results are shown in terms of streamlines and isotherms during th</span>eir transient evolution.展开更多
We describe the fabrication of silicon micro-hemispheres by adopting the conventional laser ablation of single crystalline silicon in the vacuum condition without using any catalysts or additives. The highly oriented ...We describe the fabrication of silicon micro-hemispheres by adopting the conventional laser ablation of single crystalline silicon in the vacuum condition without using any catalysts or additives. The highly oriented structures of silicon micro-hemispheres exhibit many periodic nanoscale rings along their outer surfaces. We consider that the self-organized growth of silicon micro-structures is highly dependent on the laser intensity and background air medium. The difference between these surface modifications is attributed to the amount of laser energy deposited in the silicon material and the consequent cooling velocity.展开更多
报告以脑积水起病的晚发型戊二酸血症1型(glutaric acidemia type 1,GA1)1例。患者女性,21岁,以急性脑积水为主要临床表现,头颅MRI示脑内大范围脑白质、双侧基底节区及小脑半球蚓部异常信号,双侧脑室扩张,双侧颞极蛛网膜囊肿。血尿有机...报告以脑积水起病的晚发型戊二酸血症1型(glutaric acidemia type 1,GA1)1例。患者女性,21岁,以急性脑积水为主要临床表现,头颅MRI示脑内大范围脑白质、双侧基底节区及小脑半球蚓部异常信号,双侧脑室扩张,双侧颞极蛛网膜囊肿。血尿有机酸分析检出大量戊二酸和3-羟基戊二酸,GCDH基因检测发现为复合杂合性突变(S119L和R355H),确诊为戊二酸血症1型,给予相关治疗后,症状缓解。可见临床上如遇上难以解释的脑积水,头部MRI示典型对称性病灶,包括小脑损害,应进行血尿有机酸筛查以除外代谢性疾病。展开更多
陆气耦合是地表与大气之间物质能量交换的重要一环,深入研究陆气耦合的时空变化特征,对认识陆气耦合在全球气候变化中的作用有重要意义。基于1950—2020年全球陆面数据同化系统(Global Land Data Assimilation System,GLDAS)土壤湿度、...陆气耦合是地表与大气之间物质能量交换的重要一环,深入研究陆气耦合的时空变化特征,对认识陆气耦合在全球气候变化中的作用有重要意义。基于1950—2020年全球陆面数据同化系统(Global Land Data Assimilation System,GLDAS)土壤湿度、欧洲中期天气预报中心陆面再分析数据集(ERA5-Land)和全球降水气候中心(Global Precipitation Climatology Centre,GPCC)的降水数据,计算反映土壤水分对降水的反馈(λ)、潜热通量对土壤湿度的变化响应程度(ISM-LH)和降水对地表潜热通量变化响应程度(ILH-Pr)的3种陆气耦合指数,从不同角度分析北半球陆气耦合强度及其空间分布特征,确定北半球陆气耦合关键区。在此基础上,分析过去近70 a北半球陆气耦合的时空变化特征。结果表明,ISM-LH能较好地反映土壤湿度-蒸发耦合过程,对陆气耦合强度代表性最好。北半球有5个陆气耦合关键区,分别为北美耦合关键区(NA)、地中海耦合关键区(MS)、中亚-蒙古耦合关键区(CM)、非洲耦合关键区(AF)和南亚耦合关键区(SA)。夏季陆气耦合关键区的范围最广、耦合强度最强,春季次之。春夏之间的前后期耦合强度弱于春、夏季同期的耦合强度。1950—2020年陆气耦合关键区年耦合强度具有明显的线性变化趋势,NA、SA、AF关键区陆气耦合强度呈现减弱趋势,其中AF夏季减弱趋势最明显,气候倾向率为-3.61/10 a(p<0.01);MS和CM的陆气耦合强度呈现增强趋势,其中CM夏季的线性变化趋势最明显,气候倾向率为2.28/10 a(p<0.01)。在耦合关键区,陆气耦合强度和降水的线性变化趋势在NA和MS呈反相变化,在AF和SA为同相变化;同期的陆气耦合强度异常与降水异常呈显著负相关,春季的负相关在MS最显著(r=-0.469,p<0.01),夏季的负相关在AF最显著(r=-0.821,p<0.01)。展开更多
基金the National Natural Science Foundation of China(Nos.51972101,11874143)the Natural Science Foundation of Hubei Province(No.2019CFB508)the Application Fundamental Research Project of Wuhan Science and Technology Bureau(No.2019010701011396).
文摘The carrier transport layer with reflection reduction morphology has attracted extensive attention for improving the utilization of light.Herein,we introduced single-layer hollow ZnO hemisphere arrays(ZHAs)behaving light trapping effect as the electron transport layer in perovskite photodetectors(PDs).The singlelayer hollow ZHAs can not only reduce the reflection,but also widen the angle of the effective incident light and especially transfer the distribution of the optical field from the ZnO/FTO interface to the perovskite active layer confirmed by the 3D finitedifference time-domain simulation.These merits benefit for the generation,transport and separation of carriers,improving the light utilization efficiency.Finally,our optimized FTO/ZHA/CsPbBr3/carbon structure PDs showed high self-powered performance with a linear dynamic range of 120.3 dB,a detectivity of 4.2×10^(12) Jones,rise/fall time of 13/28μs and the f_(−3) dB of up to 28 kHz.Benefiting from the high device performance,the PD was demonstrated to the application in the directional transmission of encrypted files as the signal receiving port with super high accuracy.This work uniquely utilizes the features of high-performance self-powered perovskite PDs in optical communication,paving the path to wide applications of all-inorganic perovskite PDs.
基金supported by grants from the Health Innovation Talents Project of Zhejiang Province of China,No.2016the National Natural Science Foundation of China,No.81571626,U1404823+2 种基金the Natural Science Foundation of Zhejiang Province of China,No.LY15H220001the Medical and Health Research Project of Zhejiang Province of China,No.2014KYA134the Wenzhou Bureau of Science and Technology of China,No.Y20140731,Y20150087
文摘Cerebral ischemia not only causes pathological changes in the ischemic areas but also induces a series of secondary changes in more distal brain regions（such as the contralateral cerebral hemisphere）. The impact of supratentorial lesions, which are the most common type of lesion, on the contralateral cerebellum has been studied in patients by positron emission tomography, single photon emission computed tomography, magnetic resonance imaging and diffusion tensor imaging. In the present study, we investigated metabolite changes in the contralateral cerebral hemisphere after supratentorial unilateral ischemia using nuclear magnetic resonance spectroscopy-based metabonomics. The permanent middle cerebral artery occlusion model of ischemic stroke was established in rats. Rats were randomly divided into the middle cerebral artery occlusion 1-, 3-, 9-and 24-hour groups and the sham group. ~1H nuclear magnetic resonance spectroscopy was used to detect metabolites in the left and right cerebral hemispheres. Compared with the sham group, the concentrations of lactate, alanine, γ-aminobutyric acid, choline and glycine in the ischemic cerebral hemisphere were increased in the acute stage, while the concentrations of N-acetyl aspartate, creatinine, glutamate and aspartate were decreased. This demonstrates that there is an upregulation of anaerobic glycolysis（shown by the increase in lactate）, a perturbation of choline metabolism（suggested by the increase in choline）, neuronal cell damage（shown by the decrease in N-acetyl aspartate） and neurotransmitter imbalance（evidenced by the increase in γ-aminobutyric acid and glycine and by the decrease in glutamate and aspartate） in the acute stage of cerebral ischemia. In the contralateral hemisphere, the concentrations of lactate, alanine, glycine, choline and aspartate were increased, while the concentrations of γ-aminobutyric acid, glutamate and creatinine were decreased. This suggests that there is a difference in the metabolite changes induced by ischemic injury in the contralateral and ipsilateral cerebral hemispheres. Our findings demonstrate the presence of characteristic changes in metabolites in the contralateral hemisphere and suggest that they are most likely caused by metabolic changes in the ischemic hemisphere.
文摘The emissions of biophotons have been considered a ubiquitous property of living systems and their components. We measured the “spontaneous” photon emissions from fixed whole and sectioned human brains within hyper-dark settings. Significant differences in photon counts were measured from different spatial planes. The flux densities were in the order of 2 × 10<sup>-12</sup> W per m<sup>2</sup>. The right hemispheres but not the left hemispheres displayed more photon emissions whose spectral power density profiles exhibited a conspicuous amplitude peak between 7.9 and 8 Hz. Brains measured in the hyperdark (~10<sup>-12</sup> W·m<sup>2</sup>) after removal from the typical lighting of the laboratory emitted more photons than those that had been maintained in the hyperdark for one week. The significant correlation between the numbers of photons emitted from the left hemisphere (but not the right) and global geomagnetic activity also exhibited energy equivalence between the photon flux densities and the geomagnetic shift within the cerebral volumes. These results indicate that what has been assumed to be fixed unresponsive human brain tissue still emits small numbers of photons that may be residuals from ambient light and can potentially interact with global geomagnetic activity. The medical implications for post-mortem intrinsic photonic information based upon the anisotropic microstructures within the hemispheres of the human cerebrum are discussed.
文摘Natural convection heat transfer in open or closed cavities takes place in different engineering areas. The hemispherical cavity is a part of basic geometries although it is not widely studied. The present paper reports the numerical study of natural convection in a closed hemispherical annulus delimited by two vertically eccentric hemispheres filled with Newtonian fluid (air in this case with <em>Pr</em> = 0.7) is conducted. The inner hemisphere is heated by a heat flux of constant density and the outer one is maintained isothermal. Based on the Boussinesq assumptions, the governing equations are numerically studied using unsteady natural convection formulated with vorticity and stream-function variables. These equations are written by using bispherical coordinates system and solved by using a finite difference method. The effect of the control parameters such as the Rayleigh number (<span style="white-space:nowrap;">10<sup>3</sup> ≤ <em>Ra</em> ≤ 10<sup>6</sup></span>) or the eccentricity (<em>e</em> = ±0.2, ±0.5, 0) in the dynamic and thermal behaviours of the fluid is investigated.
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.52071160 and 52071203)the National Natural Science Foundation of Jiangsu Province(Grant Nos.BK20190103 and BK20190964)the Six Talent Peaks Project of Jiangsu Province(Grant No.KTHY-068).
文摘This study aimed to restore the ultimate strength of dented stainless-steel hemispheres with a radius of 90 mm and a thickness of 0.86 mm.All of the hemispheres were subjected to external hydrostatic pressure.Small stainless-steel stiffened caps were used to eliminate the effect of indention on the ultimate strength.These caps had a radius of 36 mm,a thickness of 0.76 mm,and a height of 10.44 mm.Six hemispherical samples,including two intact hemispheres,two dented hemispheres without stiffening,and two dented hemispheres with stiffening,were prepared.Each hemi-sphere was geometrically measured for shape and thickness,hydrostatically tested for destruction,and numerically evaluated for comparison.The experimental and numerical data agreed well with each other.As a result,a spherical cap can effectively restore the ultimate strength of dented hemispheres under external hydrostatic pressure.The proposed restoration approach can be used to strengthen underwater pressure hulls with large local geometric imperfections.
基金National Natural Science Foundation of China(4133042541175062)
文摘By employing the singular value decomposition(SVD) analysis, we have investigated in the present paper the covariations between circulation changes in the Northern(NH) and Southern Hemispheres(SH) and their associations with ENSO by using the NCEP/NCAR reanalysis, the reconstructed monthly NOAA SST, and CMAP precipitation along with NOAA Climate Prediction Center(CPC) ENSO indices. A bi-hemispheric covariation mode(hereafter BHCM) is explored, which is well represented by the first mode of the SVD analysis of sea surface pressure anomaly(SLPA-SVD1). This SVD mode can explain 57.36% of the total covariance of SLPA. BHCM varies in time with a long-term trend and periodicities of 3—5 years. The long term trend revealed by SVD1 shows that the SLP increases in the equatorial central and eastern Pacific but decreases in the western Pacific and tropical Indian Ocean, which facilitates easterlies in the lower troposphere to be intensified and El Ni觡o events to occur with lower frequency. The spatial pattern of the BHCM looks roughly symmetric about the equator in the tropics, whereas it is characterized by zonal disturbances in the mid-latitude of NH and is highly associated with AAO in the mid-latitude of SH. On inter-annual time scales, the BHCM is highly correlated with ENSO. The atmosphere in both the NH and SH responds to sea surface temperature anomalies in the equatorial region, while the contemporaneous circulation changes in the NH and SH in turn affect the occurrence of El Ni觡o/La Ni觡a. In boreal winter, significant temperature and precipitation anomalies associated with the BHCM are found worldwide. Specifically, in the positive phase of the BHCM,temperature and precipitation are anomalously low in eastern China and some other regions of East Asia. These results are helpful for us to better understand interactions between circulations in the NH and SH and the dynamical mechanisms behind these interactions.
文摘BACKGROUND： Certain neural functions, such as peripheral reflexes, differ between genders, while higher brain functions, such as language, are asymmetrically distributed between the two hemispheres. The question remains as to whether depth perception differs between hemispheric laterality and genders, and whether it is affected by eye dominance. OBJECTIVE： To determine whether depth perception is influenced by factors such as gender, eye dominance, and hemispheric lateralization by recording evoked potential associated with depth perception. DESIGN, TIME AND SETTING： A contrast observation based on neuroelectrophysiology was performed at the Department of Biophysics of Ege University Medical School between June 2006 and April 2007. PARTICIPANTS： A total of 34 subjects, 19 females and 15 males, were included in the study with a mean age of （31.0 ± 6.9） years. All subjects were free of neurological or psychological disorders, or problems such as strabismus or vision correction. METHODS： Random-dot stereograms were used to elicit brain activity. A specially designed signal acquisition system employing two computers was used to record evoked potentials from both hemispheres via two pairs of scalp electrodes placed over the occipitotemporal areas of both hemispheres at symmetrical locations. MAIN OUTCOME MEASURES： Negative potential with a mean latency of （211.21 ±25.55） ms and a mean amplitude of （6.05 ± 1.53） pV was recorded from both occipitotemporal areas in 30 out of 34 participants. This was termed ＂Nd＂ and represented the evoked potential associated with depth perception. RESULTS： There were no significant differences in Nd amplitude or latency between the two hemispheres, the two eyes, or genders （P 〉 0.05）. CONCLUSION： The evoked potential associated with depth perception was not influenced by gender, hemisphere, or eye dominance.
基金The corresponding author would like to acknowledge the Research Grant of Pukyong National University(2019).
文摘This paper focusses on steel-welded hemispherical shells subjected to external hydrostatic pressure.The experimental and numerical investigations were performed to study their failure behaviour.The model was fabricated from mild steel and made through press forming and welding.We therefore considered the effect of initial shape imperfection,variation of thickness and residual stress obtained from the actual structures.Four hemisphere models designed with R/t from 50 to 130 were tested until failure.Prior to the test,the actual geometric imperfection and shell thickness were carefully measured.The comparisons of available design codes(PD 5500,ABS,DNV-GL)in calculating the collapse pressure were also highlighted against the available published test data on steel-welded hemispheres.Furthermore,the nonlinear FE simulations were also conducted to substantiate the ultimate load capacity and plastic deformation of the models that were tested.Parametric dependence of the level of sphericity,varying thickness and residual welding stresses were also numerically considered in the benchmark studies.The structure behaviour from the experiments was used to verify the numerical analysis.In this work,both collapse pressure and failure mode in the numerical model were consistent with the experimental model.
文摘The subject of natural convection heat transfer is motivated by a wide range of applications in engineering technology. The hemispherical cavity is a part of basic geometries although it is not widely studied. The effect of inclinaison on natural convection fluid motions in the gap between two eccentric hemispheres is numerically studied. The inner hemisphere is subjected to a heat flux of a constant density and the outer one is maintened isothermal. The walls separating the two hemispheres are thermally adiabatic. Equations are formulated with vorticity and stream-functions variables. It is also assumed the fluid incompressible and obeys the approximation of Boussinesq. These equations are written by using bispherical coordinates system and solved by using a finite difference method. The results show the topology of flow is strongly dependent on the inclinaison because the flow can change from a unicellular regime to a multicellular regime by varying the inclination from 0 to π. By increasing the Rayleigh number (10<sup>3</sup><<i>Ra</i><10<sup>7</sup>), the flow intensifies. T<span style="letter-spacing:-0.05pt;">he results are shown in terms of streamlines and isotherms during th</span>eir transient evolution.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11105085 and 11075097)the Excellent Youth and Middle Age Scientists Fund of Shandong Province,China (Grant No.BS2012CL024)the Project of Higher Educational Science and Technology Program of Shandong Province,China (Grant No.J12LA51)
文摘We describe the fabrication of silicon micro-hemispheres by adopting the conventional laser ablation of single crystalline silicon in the vacuum condition without using any catalysts or additives. The highly oriented structures of silicon micro-hemispheres exhibit many periodic nanoscale rings along their outer surfaces. We consider that the self-organized growth of silicon micro-structures is highly dependent on the laser intensity and background air medium. The difference between these surface modifications is attributed to the amount of laser energy deposited in the silicon material and the consequent cooling velocity.
文摘报告以脑积水起病的晚发型戊二酸血症1型(glutaric acidemia type 1,GA1)1例。患者女性,21岁,以急性脑积水为主要临床表现,头颅MRI示脑内大范围脑白质、双侧基底节区及小脑半球蚓部异常信号,双侧脑室扩张,双侧颞极蛛网膜囊肿。血尿有机酸分析检出大量戊二酸和3-羟基戊二酸,GCDH基因检测发现为复合杂合性突变(S119L和R355H),确诊为戊二酸血症1型,给予相关治疗后,症状缓解。可见临床上如遇上难以解释的脑积水,头部MRI示典型对称性病灶,包括小脑损害,应进行血尿有机酸筛查以除外代谢性疾病。
