Effect of different cold air intensities and their lagged effects on outpatient visits for respiratory illnesses in Handan in different seasons

本文利用2016年到2019年邯郸市气象要素和呼吸系统疾病门诊数据,分析了不同季节不同强度的冷空气过程及其对呼吸系统疾病的影响,结果显示:尽管呼吸系统疾病在冬季高发,夏季最低,但冷空气对呼吸系统疾病的影响在夏,春季最大,就诊人数分别在冷空气日后两天和五天增加18.4%和13.3%,而冬季就诊人数在冷空气日后三天仅增加3.2%.冷空气对疾病影响的滞后时间在夏,秋和冬季随冷空气强度的增加而减少,而春季的滞后时间总是很长.这些发现可为科学应对气候异常导致的人群健康风险提供针对性依据.

Monitoring models for base flow effect and daily variation of dam seepage elements considering time lag effect

Affected by external environmental factors and evolution of dam performance, dam seepage behavior shows nonlinear time-varying characteristics. In this study, to predict and evaluate the long-term development trend and short-term fluctuation of the dam seepage behavior, two monitoring models were developed, one for the base flow effect and one for daily variation of dam seepage elements. In the first model, to avoid the influence of the time lag effect on the evaluation of seepage variation with the time effect component of seepage elements, the base values of the seepage element and the reservoir water level were extracted using the wavelet multi-resolution analysis method, and the time effect component was separated by the established base flow effect monitoring model. For the development of the daily variation monitoring model for dam seepage elements, all the previous factors, of which the measured time series prior to the dam seepage element monitoring time may have certain influence on the monitored results, were considered. Those factors that were positively correlated with the analyzed seepage element were initially considered to be the support vector machine(SVM) model input factors, and then the SVM kernel function-based sensitivity analysis was performed to optimize the input factor set and establish the optimized daily variation SVM model. The efficiency and rationality of the two models were verified by case studies of the water level of two piezometric tubes buried under the slope of a concrete gravity dam.Sensitivity analysis of the optimized SVM model shows that the influences of the daily variation of the upstream reservoir water level and rainfall on the daily variation of piezometric tube water level are processes subject to normal distribution.

Closed-form solution to thin-walled box girders considering effects of shear deformation and shear lag

Considering three longitudinal displacement functions and uniform axial displacement functions for shear lag effect and uniform axial deformation of thin-walled box girder with varying depths,a simple and efficient method with high precision to analyze the shear lag effect of thin-walled box girders was proposed.The governing differential equations and boundary conditions of the box girder under lateral loading were derived based on the energy-variational method,and closed-form solutions to stress and deflection corresponding to lateral loading were obtained.Analysis and calculations were carried out with respect to a trapezoidal box girder under concentrated loading or uniform loading and a rectangular box girder under concentrated loading.The analytical results were compared with numerical solutions derived according to the high order finite strip element method and the experimental results.The investigation shows that the closed-form solution is in good agreement with the numerical solutions derived according to the high order finite strip method and the experimental results,and has good stability.Because of the shear lag effect,the stress in cross-section centroid is no longer zero,thus it is not reasonable enough to assume that the strain in cross-section centroid is zero without considering uniform axial deformation.

Closed-form solution for shear lag effects of steel-concrete composite box beams considering shear deformation and slip

Based on the consideration of longitudinal warp caused by shear lag effects on concrete slabs and bottom plates of steel beams,shear deformation of steel beams and interface slip between steel beams and concrete slabs,the governing differential equations and boundary conditions of the steel-concrete composite box beams under lateral loading were derived using energy-variational method.The closed-form solutions for stress,deflection and slip of box beams under lateral loading were obtained,and the comparison of the analytical results and the experimental results for steel-concrete composite box beams under concentrated loading or uniform loading verifies the closed-form solution.The investigation of the parameters of load effects on composite box beams shows that:1) Slip stiffness has considerable impact on mid-span deflection and end slip when it is comparatively small;the mid-span deflection and end slip decrease significantly with the increase of slip stiffness,but when the slip stiffness reaches a certain value,its impact on mid-span deflection and end slip decreases to be negligible.2) The shear deformation has certain influence on mid-span deflection,and the larger the load is,the greater the influence is.3) The impact of shear deformation on end slip can be neglected.4) The strain of bottom plate of steel beam decreases with the increase of slip stiffness,while the shear lag effect becomes more significant.

Effects of time lag and stress loading rate on permeability in low permeability reservoirs

In order to study the effect of time lag and stress loading rates on rock deformation,the conventional stepped stress loading mode was changed into a continuous mode to investigate the effect of effective pressure on permeability and porosity.The time lag effect of rock deformation illustrating the relationship between changes in permeability and steady time was studied.Permeability reduction ratios were measured under different stress loading rates which were achieved by different pump rate settings.The results show that permeability and porosity gradually decrease with increases in effective pressure.Permeability at high effective pressure attains stability quickly.Steady times at low effective pressure are very long.Reduction in permeability at lower stress loading rates is small,while,in contrast,it is large at high stress loading rates.

Theoretical and experimental study on shear lag effect of partially cable-stayed bridge

In order to resolve the traffic congestion problem, many cable-stayed bridges are designed with a large width to span ratio. This results in significant shear lag effect to cause nonuniform stress distribution along the flanges of the beam of bridge. This paper reports study on the shear lag effect of the Lanzhou Xiaoxihu Yellow River Bridge. A 3D finite element model of the bridge was developed and finite element analysis (FEA) was done to obtain the theoretical results. To evaluate the theoretical results, a scaled model was made to conduct static test in laboratory. The experiment results accorded with the results obtained by FEA. It is proved that FEA is an effective method to predict shear lag effect of bridges of this type.

PERIODIC AND ALMOST PERIODIC SOLUTIONS FOR A NON-AUTONOMOUS RESPIRATORY DISEASE MODEL WITH A LAG EFFECT

This paper studies a kind of non-autonomous respiratory disease model with a lag effect.First of all,the permanence and extinction of the system are discussed by using the comparison principle and some differential inequality techniques.Second,it assumes that all coefficients of the system are periodic.The existence of positive periodic solutions of the system is proven,based on the continuation theorem in coincidence with the degree theory of Mawhin and Gaines.In the meantime,the global attractivity of positive periodic solutions of the system is obtained by constructing an appropriate Lyapunov functional and using the Razumikin theorem.In addition,the existence and uniform asymptotic stability of almost periodic solutions of the system are analyzed by assuming that all parameters in the model are almost periodic in time.Finally,the theoretical derivation is verified by a numerical simulation.

Experimental Study on Shear Lag Effect of Partial Cable-Stayed Bridge and Elasto-Plastic Seismic Analysis

The project of Xiaoxihu Yellow River Bridge in Lanzhou is chosen as partial cable-stayed bridge. To get the shear lag effect and anti-earthquake performance of the actual bridge under various loading conditions, organic glass scaled model was adopted to have an experiment and a theory research at one time. The experiment result is the basically same as the theory calculation which proves the FEA method can well calculate shear lag effect and dynamical performance. As a result, because the bridge is located in a seismic area of 8 degree, an elasto-plastic seismic checking is performed by customized FEA program in this paper.

固定宽度结构等离子体刻蚀中Lag效应的数值模拟

为了对传感器设计与制造中的刻蚀过程进行研究，本文利用等离子体～硅表面交互作用的动力学机制和算法的优化，建立了一种时空归一化的等离子体刻蚀硅片二维模型，并利用该模型，从固定结构尺寸的角度对等离子体刻蚀中的重要现象——Lag效应进行了揭示，证明在固定宽度结构的刻蚀中存在刻蚀速率随时间变小的现象。同时还对刻蚀算法中的时间步长选择问题进行了讨论，从数值计算的角度提出了最优时间步长的概念并加以验证。为工艺过程的数值模拟及实验提供参考和指导。

Analysis of free vibration characteristic of steel-concrete composite box-girder considering shear lag and slip

Based on Hamilton principle,the governing differential equations and the corresponding boundary conditions of steel-concrete composite box girder with consideration of the shear lag effect meeting self equilibrated stress,shear deformation,slip,as well as rotational inertia were induced.Therefore,natural frequency equations were obtained for the boundary types,such as simple support,cantilever,continuous girder and fixed support at two ends.The ANSYS finite element solutions were compared with the analytical solutions by calculation examples and the validity of the proposed approach was verified,which also shows the correctness of longitudinal warping displacement functions.Some meaningful conclusions for engineering design were obtained.The decrease extent of each order natural frequency of the steel-concrete composite box-girder is great under action of the shear lag effect.The shear-lag effect of steel-concrete composite box girder increases when frequency order rises,and increases while span-width ratio decreases.The proposed approach provides theoretical basis for further research of free vibration characteristics of steel-concrete composite box-girder.

Local inhibition of GABA affects precedence effect in the inferior colliculus

The precedence effect is a prerequisite for faithful sound localization in a complex auditory environment, and is a physiological phenomenon in which the auditory system selectively suppresses the directional information from echoes. Here we investigated how neurons in the inferior colliculus respond to the paired sounds that produce precedence-effect illusions, and whether their firing behavior can be modulated through inhibition with gamma-aminobutyric acid （GABA）. We recorded extracellularly from 36 neurons in rat inferior colliculus under three conditions： no injection, injection with saline, and injection with gamma-aminobutyric acid. The paired sounds that produced precedence effects were two identical 4-ms noise bursts, which were delivered contralaterally or ipsilaterally to the recording site. The normalized neural responses were measured as a function of different inter-stimulus delays and half-maximal interstimulus delays were acquired. Neuronal responses to the lagging sounds were weak when the inter-stimulus delay was short, but increased gradually as the delay was lengthened. Saline injection produced no changes in neural responses, but after local gamma-arninobutyric acid application, responses to the lagging stimulus were suppressed. Application of gamma-aminobutyric acid affected the normalized response to lagging sounds, independently of whether they or the paired sounds were contralateral or ipsilateral to the recording site. These observations suggest that local inhibition by gamma-aminobutyric acid in the rat inferior colliculus shapes the neural responses to lagging sounds, and modulates the precedence effect.

深槽刻蚀工艺中lag效应的研究(英文)

等离子体深刻蚀技术是MEMS制备的关键,利用该技术进行刻蚀时,会出现lag效应和反常lag效应,严重影响器件的性能。为了消除lag效应,建立刻蚀和钝化模型分析lag的产生,并利用ARDE表征lag。采用"四因子-三水平"的正交实验研究不同工艺参数对lag的影响,得到工艺参数影响lag的优先级:线圈功率和极板功率对lag产生影响最大,与此同时得到一组最优的实验参数。在低线圈功率和低极板功率条件下,研究了改变压强和气体流量对lag的影响,增加压强和气体流量都会减小lag。最终通过优化工艺参数得到了反常lag结构和lag消除的刻蚀结构。

Impact of the Urban Heat Island Effect on Ozone Pollution in Chengdu City,China

With the advancement of urbanization,the urban heat island effect and ozone pollution have become hot issues in urban research.The urban heat island effect can impact ozone conversion,but its mechanism of action is unclear.In this study,the effects of the urban heat island effect on ozone concentration in Chengdu City,China,were investigated by comparing the ozone concentration under different heat island levels with ozone data from March 2020 to February 2021 and the temperature and wind field data of ERA5-Land during the same period.The results showed that:1)regarding the distribution characteristics,the ozone concentration in Chengdu presented a‘high in summer and low in winter’distribution.The ozone concentration in summer(189.54µg/m^(3))was nearly twice that in winter(91.99µg/m^(3)),and the ozone diurnal variation presented a‘single peak and single valley’distribution,with a peak at 16:00.2)For the characteristics of the heat island effect,the heat island intensity in Chengdu was obviously higher in spring than in other seasons,and the diurnal variation showed a‘single peak and single valley’distribution,with the peak and trough values appearing at 9:00 and 17:00,respectively.Spatially,the eastern part of Chengdu was a heat island,while the western and northwestern parts were mostly cold island.3)The correlation analysis between heat island intensity and ozone concentration showed a significant positive correlation but with a 7–8 h time lag.Ambient air temperature was not the main factor affecting ozone concentration.The heat island effect impacts the ozone concentration in two ways:changing the local heat budget to promote ozone generation and forming local urban wind,which promotes ozone diffusion or accumulation and forms different areas of low and high ozone values.

Application Study on Correction Method for Lag of Water Level Response to Earth Tide and Atmospheric Pressure

The water level in a deep well instantly responds to the earth’s tide and atmospheric pressure, and varies accordingly, not only in terms of amplitude but also in the phase lag. Therefore, phase lag correction is used in analyzing digital groundwater observation data in eastern China. Calculation results presented by the authors in this paper show that the correction method is effective in the identification of anomalous changes for short-term seismic precursors. The correction method can also be applied to the processing of observed deformation and tilt data.

数字普惠金融的民生福祉效应:“红利”与“鸿沟”

数字普惠金融比传统金融具有更好的地理穿透性,为增进民生福祉,破解“胡焕庸线魔咒”提供了可能,但较少有文献对此进行系统研究。论文基于中国民生发展指数和数字普惠金融指数,利用空间统计与计量方法,从市级层面系统考察了数字普惠金融的民生福祉效应,并分析了以胡焕庸线为界的区域异质性特征。研究发现:数字普惠金融指数和民生福祉指数具有明显的空间分布异质性特点,呈现“高值向东南集聚、低值向西北集聚”的趋势。数字普惠金融与民生福祉皆存在显著的空间关联性,空间集聚特征明显且呈两极分化格局,胡焕庸线仍是两者的重要空间分界线;高-高集聚主要分布在胡焕庸线东南侧的沿海城市,低-低集聚主要分布在靠近胡焕庸线两侧的城市。数字普惠金融显著增进了民生福祉,发挥出“数字红利”的普惠作用;该作用在胡焕庸线东南侧城市显著高于西北侧城市,但两侧差距在缩小,这说明区域“鸿沟”在缩小,“胡焕庸线魔咒”有望破解。此外,研究还显示数字普惠金融的覆盖广度和使用深度是增进民生福祉的主要驱动力,而且后者的作用大于前者。因此,要加快西部地区数字基础设施与相关技术发展,提升胡焕庸线西北侧城市数字普惠金融的覆盖广度与使用深度,以增进区域民生福祉均衡性和可及性。

环境补贴能提升企业碳绩效吗--基于A股上市公司实证分析

环境补贴既是国家实现“双碳”目标的宏观调控手段,也是减轻企业环保负担、引导企业节能减排的推动力。选取2014~2019年接受环境补贴的1094家A股上市公司3735个观测值作为研究样本,采用双向固定效应模型,实证探究环境补贴对企业碳绩效的影响。研究表明,环境补贴与企业碳绩效显著正相关且具有滞后性特征,异质性检验发现,成立时间长的企业、国有企业、东部地区与中低污染企业环境补贴作用效果显著;进一步研究发现,环境补贴中的节能减排补贴与企业碳绩效显著正相关,环境治理补贴对企业碳绩效起负向作用。据此,提出环境补贴应以降碳为重点、减污降碳协同增效为目的等建议。

偏载作用下薄壁箱梁空间整体效应的综合分析

为了研究斜腹板箱梁在竖向偏心荷载作用下的受力性能,在合理构造各翘曲位移函数的基础上,用能量变分法建立全面反映竖向弯曲变形以及剪力滞、约束扭转、畸变等翘曲变形的控制微分方程,通过对既有文献中的模型梁进行计算分析,明确剪力滞、约束扭转及畸变翘曲应力在竖向弯曲应力中的占比情况,并揭示各翘曲广义内力的分布规律。结果表明:按文章解析法求得的模型梁应力理论值与实测值吻合良好,从而验证文章方法的合理性;在偏载作用下箱梁的约束扭转微分方程与畸变微分方程是相互耦联的,这在已有文献中往往被忽略;在剪力滞、约束扭转及畸变翘曲应力中,畸变翘曲应力占据主导地位,剪力滞和约束扭转翘曲应力相对较小,但仍不可忽略,在控制截面上因各种翘曲变形引起的应力放大系数达到1.362;偏心集中荷载引起的各翘曲广义内力均具有快速衰减的分布规律,剪力滞和约束扭转广义内力分布范围很小,而畸变广义内力分布范围广阔。建议在桥梁设计规范相关条文及实际箱梁桥设计中,对畸变效应给予充分重视。

红锥树干径向水分亏缺对饱和水汽压差的时滞响应

【目的】探索作为树干水分变化状况指标的树木水分亏缺(TWD)变化特征及其与饱和水汽压差(VPD)的关系,揭示径向变化对环境水分胁迫的响应特征,为合理指导红锥人工林经营提供科学依据和数据支持。【方法】利用径向变化记录仪记录不同分化等级红锥树干径向变化过程,同步监测环境因子,分析TWD对VPD的响应特征。【结果】不同分化等级红锥的TWD波动趋势相似,TWD随着VPD的变化而变化,但并不同步。小时尺度上,TWD和VPD显著正相关(r=0.488,r=0.489,r=0.512,P<0.01),划分失水期和复水期后,两个时期的TWD和VPD也显著正相关,且失水期的相关性增强(r=0.623,r=0.667,r=0.593,P<0.01)。日尺度上,无论是否划分失水期和复水期,二者均显著正相关,但相关性减弱。前后1天内的时滞响应分析结果显示,无论分化等级,TWD与VPD显著正相关(P<0.01);划分失水期和复水期后,在任何时间段考虑时滞响应时也均达到显著正相关,失水期的相关性强于复水期的相关性。未划分失水期和复水期时,不同分化等级红锥TWD对VPD响应滞后时间均为3 h。划分失水期和复水期后,失水期TWD对VPD响应滞后时间缩短,复水期TWD对VPD响应滞后时间延长。优势木、中等木和被压木复水期的滞后时间比失水期分别长3、4和5 h。VPD大幅度波动条件(VPD_(L))下,随着VPD的反复升降,TWD表现为失水-复水交替出现,变化的总体趋势是上升的;VPD小幅度波动条件(VPDs)下,TWD变化趋势较平缓,两种条件下TWD对VPD的响应均存在时滞。无论分化等级,VPD_(L)条件下TWD与VPD之间的相关性(r=0.550,r=0.553,r=0.584,P<0.01)均强于VPDs下的相关性(r=0.256,r=0.260,r=0.281,P<0.01)。VPDL条件下,考虑滞后时间后,无论是否划分失水期和复水期,不同分化等级红锥TWD与VPD之间的相关性均增强。VPDs条件下,复水期的相关性低于忽略时滞效应时的相关性。【结论】TWD对VPD的响应存在时滞效应,在失水期和复水期,TWD对VPD的响应特征不同,且在不同分化等级间存在差异;失水期和复水期的划分有助于研究TWD与VPD的相关性。

从同步数据分析乔木树干液流与气象因子的关系

[目的]树干液流是研究植物蒸腾耗水的重要生理指标,树种和气象因子均是其关键影响因素。本文旨在消除树种因素限制,探讨树干液流与气象因子之间的关系。[方法]以哈尼梯田水源区3种林分中10种乔木树种为研究对象,采用Granier热扩散探针技术测定其树干液流速率,将其同步数据与气象因子进行关联分析。[结果]从次生落叶阔叶林和原生常绿阔叶林的7779条乔木树干液流速率数据中发现7条异常数据,且这些异常数据在各个树种中都表现出同步一致性;进一步关联分析表明,太阳辐射的突然增加是产生乔木树干液流数据同步上升的主要原因,而降雨则是产生树干液流数据同步下降的主要原因,两者的变化可导致其他气象因子发生变化,从而影响树干液流速率;树干液流与气象因子存在一定的时滞效应,在发生同步异常数据的气候条件下,树干液流滞后太阳辐射0~30 min,提前于饱和水汽压差、气温和湿度0~60 min,滞后或提前时间远小于正常气候条件下各树种的时滞时间。[结论]乔木树干液流受到太阳辐射和降雨等气象因子的综合调节,其中太阳辐射的影响最为显著。研究结果可为从生理生态角度探究乔木的蒸腾作用与气象因子的关系提供科学依据。