高通量血液透析和低通量血液透析对慢性肾衰竭尿毒症的透析效果分析

目的探讨高通量血液透析和低通量血液透析对慢性肾衰竭尿毒症的透析效果。方法将2015年5月~2017年4月作为本次研究时间段,在该时间段内选择90例无典型特殊性的慢性肾衰竭尿毒症患者作为研究案例。根据随机数字法原则将90例患者划分为实验组与常规组。两组患者均应用相同的血液灌注治疗方案,常规组的血通量为200 ml/min,实验组血通量为250 ml/min。统计并对比两组患者的治疗效果以及透析器凝血状况。结果实验组患者的治疗总有效率(93.33%)与常规组患者的治疗总有效率(95.56%)相近,差异无统计学意义(P>0.05);实验组患者透析器凝血发生率显著低于常规组,差异有统计学意义(P<0.05)。结论不同血通量在治疗效果方面无明显差异,但是高通量可以有效降低透析器凝血问题,一定程度优化临床治疗效益,值得推广。

终端区进场流的路径选择研究

在实际运行中,通常依据管制员的经验对进场航班流的路径进行管理,缺乏科学性。针对终端区进场流的路径选择与进场排序的流量管理问题,以进场航班的总完成时间最短为目标,建立基于时间窗与位置约束的路径选择与排序的数学模型。采用先选择路径再排序的循环寻优的方法进行求解,将禁忌搜索(TS)与排序算法相结合,设计了TS-FCFS与TS-DP两种算法,着重建立了基于关键路径的邻域结构,并加入有效的重置(RESTAR)策略,使算法快速有效的收敛至最优解。最后借助SIMMOD仿真平台验证算法的可行性。以北京首都机场21架航班为例,仿真结果显示,TS-FCFS与TS-DP两种方法较原计划的进场路径总完成时间分别节约了149s与175s。该路径选择算法降低了进场时间,提高了终端区进场效率。通过合理优化进场航班流的路径选择与进场排序,平衡了跑道负荷,减少了航空器间潜在的冲突,同时为管制员调配进场航班流提供了合理有效的路径选择建议。

2021年5月甘肃白银一次强对流天气过程诊断分析

本文对2021年5月22日在甘肃省白银市一次强对流天气的进行分析,从强对流天气过程的形成和发展过程,实况、环流形势、水汽条件、动力条件以及不稳定能量方面进行分析,在700 hPa上有较为显著的冷平流,冷暖气团在甘肃省南部地区的交汇处较为显著,为不稳定天气的产生与发展提供了较好的热力条件;在此次强对流天气过程中产生的降水,是由中低层水汽的不断聚集,并与高空干冷空气交汇所造成的;在白银地区上空有着强烈的垂直运动,动量交换频繁,加之空中槽过境,为强对流天气的发生发展提供了较好的动力条件;西北向东南倒灌的湿冷空气加强了南北温差,冷暖空气的交汇进一步加剧,使得大气层结不稳定度也增大。同时随K指数的增加,温度差也增大,这表明在垂直方向上的湍流运动增强,为强对流天气的形成与发展提供了较为有利的热力不稳定条件。

高通量血液透析串联血液灌流联合重组人促红素对肾性贫血血液透析患者微炎症状态的影响

目的探讨高通量血液透析串联血液灌流联合重组人促红素对肾性贫血血液透析患者微炎症状态的影响。方法目的选取广东省江门市新会区人民医院于2023年3月—2024年3月收治的70例肾性贫血血液透析患者为研究对象。根据治疗方法不同分为观察组和对照组,各35例。对照组采用高通量血液透析联合重组人促红素进行治疗,观察组采用高通量血液透析串联血液灌流联合重组人促红素进行治疗。比较两组的疗效、贫血指标、肾功能指标、炎症因子水平、不良反应。结果观察组治疗总有效率为100.00%(35/35),高于对照组的80.00%(28/35),差异有统计学意义(χ^(2)=5.714,P<0.05);治疗后,观察组的贫血指标均高于对照组,差异有统计学意义(P均<0.05);治疗后,观察组的肾功能指标均低于对照组,差异有统计学意义(P均<0.05);治疗后,观察组的炎症因子水平均低于对照组,差异有统计学意义(P均<0.05)。观察组不良反应发生率高于对照组,但差异无统计学意义(P>0.05)。结论采用高通量血液透析串联血液灌流联合重组人促红素进行治疗肾性贫血血液透析患者,可改善患者炎症水平,具有较好的疗效,且安全性较高。

多面体晶体从金属熔体中生长的形态分析

本文以MC碳化物在镍基高温合金熔体中的生长为研究模型,分析了多面体晶体在合金熔体中的生长过程。结果表明,晶体生长方式是向固液界面已形成的台阶上沉积,其机制属于体扩散生长。由八面体模型分析得出,枝臂的形成是由于多面体晶体各晶面上溶质通量流密度的分布不同所致。这与用球扰动分析所得到的多面体的晶面中心较稳定而顶角处稳定性较差的结论相符。从而解释了八面体顶角处容易长出枝臂的实验事实。对MC碳化物进行Auger表面成分的测试结果,支持了这一论点。

解三维扩散方程的积分内插法格式

研究三维扩散方程的数值模拟.在非正规六面体网格上,使用积分内插法建立扩散方程差分格式,涉及到27个相邻网格,适用于大变形网格上带间断系数的拟线性扩散方程的计算.叙述差分格式的建立,推导通量流和网格顶点温度的计算公式,给出了数值试验结果.

求解三维非正规六面体网格上抛物型方程的变分-差分格式

利用通量流函数解三维非正规六面体网格上抛物型方程的变分-差分格式。

Benzene and Toluene Levels Measured with DOAS During Vehicular Restrictions in Beijing

Measurements of atmospheric benzene and toluene were carried out continuously using dif- ferential optical absorption spectroscopy from August 7 to August 28 in Beijing during the period of vehicular restrictions. The correlations between traffic flows and totals of benzene and toluene were studied during the period of vehicular traffic restrictions from August 17 to August 20 and non-traffic restrictions on August 16 and August 21. The correlation coef- ficient was 0.8 between benzene and toluene. And the calculated daily mean value ratios of benzene to toluene were 0.43-0.50. During the period of vehicular restrictions, traffic flows were reduced about 11.8% and the levels of benzene and toluene were reduced by 11.4% and 12.8%, respectively. The vehicle emissions were recognized as the major sources for atmospheric benzene and toluene in Beijing.

Analysis of tidal and residual currents across semi-enclosed bay mouth based on shipboard ADCP measurements

Based on 25 hours shipboard ADCP measurements across semi-enclosed bay mouth（Kemen Channel）, time series of tidal currents over 12 sites, which distribute evenly along the transect, were constructed to improve our understanding of tidal characteristics and residuals in this region. The tidal currents in Kemen Channel were identified as the regular semidiurnal and reversing tidal flows, with its behaviour more like standing waves. Moreover, the flood currents in the lower layers were found to be ahead of that in the upper layers and vice versa for ebb tides. The major of tidal ellipse for M2 constituent was found to be larger close to the southern side of the channel, with its incline also increasing toward the south. The signs of M4 constituent were also found mainly nearby the end points of this transect, indicating the importance of nonlinearity in tidal dynamics due to the shallower topography. A two-layer structure was found for the residual currents in Kemen Channel, flowing northeastwardly out of the Bay in upper 20m and southwestwardly into the bay in the lowers. Besides approximate 4.81×10^8 m^3 water exchanges were determined between the Luoyuan Bay and outer seas by the calculation of tidal flux through Kemen Channel.

Analysis of heat pulse signals determination for sediment-water interface fluxes

The heat pulse signal is analyzed in a new way with the goals of clarifying the relationships between the variables in the heat transfer problem and simplifying the procedure for calculating sediment-water interface fluxes J. Only three parameters x0 λand pc l are needed to calculate J by the heat pulse data for this analysis method.The results show that there is a curvilinear relationship between the peak temperature arrival time and sediment-water interface fluxes and there exists a simple linear relationship between sediment-water interface fluxes and the natural log of the ratio of the temperature increase downstream from the line heat source to the temperature increase upstream from the heat source.The simplicity of this relationship makes the heat pulse sensors an attractive option for measuring soil water fluxes.

FLIGHT CONFLICT DETECTION AND RESOLUTION

The air traffic control (ATC) systems are facing more and more serious congestive because of the increasing of air traffic flow in China. One of the most available ways to solve the problem is 'free flight' that the pilots may choose the air route and flight speed suitable for them. But this will lead to the difficulties for the controllers. This paper presents how ATC genetic algorithms can be used to detect and to solve air traffic control conflicts in free flight. And it also shows that this algorithm perfectly suits for solving flight conflicts resolution because of its short computing time.

Direct computing methods for turn flows in traffic assignment

Two methods based on a slight modification of the regular traffic assignmentalgorithms are proposed to directly compute turn flows instead of estimating them from link flows orobtaining them by expanding the networks. The first one is designed on the path-turn incidencerelationship, and it is similar to the computational procedure of link flows. It applies to thetraffic assignment algorithms that can provide detailed path structures. The second utilizes thelink-turn incidence relationship and the conservation of flow on links, a law deriving from thisrelationship. It is actually an improved version of Dial's logit assignment algorithm. The proposedapproaches can avoid the shortcomings both of the estimation methods, e. g. Furness's model andFrator's model, and of the network-expanding method in precision, stability and computation scale.Finally, they are validated by numerical examples.

Research on a non-linear chaotic prediction model for urban traffic flow

In order to solve serious urban transport problems, according to the proved chaotic characteristic of traffic flow, a non linear chaotic model to analyze the time series of traffic flow is proposed. This model reconstructs the time series of traffic flow in the phase space firstly, and the correlative information in the traffic flow is extracted richly, on the basis of it, a predicted equation for the reconstructed information is established by using chaotic theory, and for the purpose of obtaining the optimal predicted results, recognition and optimization to the model parameters are done by using genetic algorithm. Practical prediction research of urban traffic flow shows that this model has famous predicted precision, and it can provide exact reference for urban traffic programming and control.

Experimental and CFD Study on the Role of Fluid Flow Pattern on Membrane Permeate Flux

This paper reports a study on the role of fluid flow pattern and dynamic pressure on the permeate flux through a micro filtration membrane in laboratory scale.For this purpose,a dead-end membrane cell equipped with a marine type impeller was used.The impeller was set to rotate in the clockwise and counter clockwise directions with the same angular velocities in order to illustrate the effect of rotation direction on permeate flux.Consequently, permeate fluxes were measured at various impeller rotational speeds.The computational fluid dynamics（CFD）predicted dynamic pressure was related to the fluxes obtained in the experiments.Using the CFD modeling,it is proven that the change in dynamic pressure upon the membrane surface has direct effect on the permeate flux.

Terminal Traffic Flow Prediction Method Under Convective Weather Using Deep Learning Approaches

In order to improve the accuracy and stability of terminal traffic flow prediction in convective weather,a multi-input deep learning(MICL)model is proposed.On the basis of previous studies,this paper expands the set of weather characteristics affecting the traffic flow in the terminal area,including weather forecast data and Meteorological Report of Aerodrome Conditions(METAR)data.The terminal airspace is divided into smaller areas based on function and the weather severity index(WSI)characteristics extracted from weather forecast data are established to better quantify the impact of weather.MICL model preserves the advantages of the convolution neural network(CNN)and the long short-term memory(LSTM)model,and adopts two channels to input WSI and METAR information,respectively,which can fully reflect the temporal and spatial distribution characteristics of weather in the terminal area.Multi-scene experiments are designed based on the real historical data of Guangzhou Terminal Area operating in typical convective weather.The results show that the MICL model has excellent performance in mean squared error(MSE),root MSE(RMSE),mean absolute error(MAE)and other performance indicators compared with the existing machine learning models or deep learning models,such as Knearest neighbor(KNN),support vector regression(SVR),CNN and LSTM.In the forecast period ranging from 30 min to 6 h,the MICL model has the best prediction accuracy and stability.

An analytical model for local-nonequilibrium solute trapping during rapid solidification

Updated version of local non-equilibrium diffusion model （LNDM） for rapid solidification of binary alloys was considered. The LNDM takes into account deviation from local equilibrium of solute concentration and solute flux fields in bulk liquid. The exact solutions for solute concentration and flux in bulk liquid were obtained using hyperbolic diffusion equations. The results show the transition from diffusion-limited to purely thermally controlled solidification with effective diffusion coefficient →0 and complete solute trapping KLNDM（v）→1 at v→vDb for any kind of solid-liquid interface kinetics. Critical parameter for diffusionless solidification and complete solute trapping is the diffusion speed in bulk liquid vDb. Different models for solute trapping at the interface with different interface kinetic approaches were considered.

Research on traffic flow forecasting model based on cusp catastrophe theory

This paper intends to describe the relationship between traffic parameters by using cusp catastrophe theory and to deduce highway capacity and corresponding speed forecasting value through suitable transformation of catastrophe model. The five properties of a catastrophe system are outlined briefly, and then the data collected on freeways of Zhujiang River Delta, Guangdong province, China are examined to ascertain whether they exhibit qualitative properties and attributes of the catastrophe model. The forecasting value of speed and capacity for freeway segments are given based on the catastrophe model. Furthermore, speed-flow curve on freeway is drawn by plotting out congested and uncongested traffic flow and the capacity value for the same freeway segment is also obtained from speed-flow curve to test the feasibility of the application of cusp catastrophe theory in traffic flow analysis. The calculating results of catastrophe model coincide with those of traditional traffic flow models regressed from field observed data, which indicates that the deficiency of traditional analysis of relationship between speed, flow and occupancy in two-dimension can be compensated by analysis of the relationship among speed, flow and occupancy based on catastrophe model in three-dimension. Finally, the prospects and problems of its application in traffic flow research in China are discussed.

Hybrid Detection and Tracking of Fast-Flux Botnet on Domain Name System Traffic

Fast-flux is a Domain Name System(DNS)technique used by botnets to organise compromised hosts into a high-availability,loadbalancing network that is similar to Content Delivery Networks(CDNs).Fast-Flux Service Networks(FFSNs)are usually used as proxies of phishing websites and malwares,and hide upstream servers that host actual content.In this paper,by analysing recursive DNS traffic,we develop a fast-flux domain detection method which combines both real-time detection and long-term monitoring.Experimental results demonstrate that our solution can achieve significantly higher detection accuracy values than previous flux-score based algorithms,and is light-weight in terms of resource consumption.We evaluate the performance of the proposed fast-flux detection and tracking solution during a 180-day period of deployment on our university’s DNS servers.Based on the tracking results,we successfully identify the changes in the distribution of FFSN and their roles in recent Internet attacks.

Car-following models of vehicular traffic

The Car-following models is a kind of microscopic simulation model for vehicular traffic, which describe the one-by-one following behaviors of vehicles in the same traffic lane. As a common traffic phenomenon, following behavior is of great importance in the micro-study of intelligent traffic control. Compared with other traffic-flow models, car-following model embodies the human factors and reflects the real traffic situation in a better way. This paper gives a systematic review of the development and actuality of car-following models by introducing and analyzing in detail the advantages and disadvantages of GHR model, OV model, CA model and fuzzy-logic model. In addition, local stability and asymptotic stability of car-following models are discussed in this paper.

Influence of solar wind energy flux on the interannual variability of ENSO in the subsequent year

Previous studies have tended to adopt the quasi-decadal variability of the solar cycle （e.g.sunspot number （SSN） or solar radio flux at 10.7 cm （F10.7） to investigate the effect of solar activity on El Ni（n）o-Southern Oscillation （ENSO）.As one of the major terrestrial energy sources,the effect of solar wind energy flux in Earth＇s magnetosphere （Ein） on the climate has not drawn much attention,due to the big challenge associated with its quantitative estimation.Based on a new Ein index estimated by three-dimensional magnetohydrodynamic simulations from a previous study,this study reveals that Ein exhibits both quasi-decadal variability （periodic 11-year） and interannual （2-4 years） variability,which has rarely before been detected by SSN and F10.7.A significant interannual relationship between the annual mean Ein and subsequent early-winter ENSO is further revealed.Following high Ein,the sea level pressure in the subsequent early winter shows significant positive anomalies from Asia southward to the Maritime Continent,and significant negative anomalies over the Southeast and Northeast Pacific,resembling the Southern Oscillation.Meanwhile,significant upper-level anomalous convergence and divergence winds appear over the western and eastern Pacific,which is configured with significant lower-level anomalous divergence and convergence,indicating a weakening of the Walker circulation.Consequently,notable surface easterly wind anomalies prevail over the eastern tropical Pacific,leading to El Ni（n