AHEAD评分联合超声心动图在急性心肌梗死后行经皮冠状动脉介入治疗患者中的治疗效果及其对预后的影响

目的探究AHEAD评分联合超声心动图在急性心肌梗死后(AMI)行经皮冠状动脉介入治疗(PCI)患者中的治疗效果以及其对预后的影响。方法选取2021年3月至2022年2月江西省中西医结合医院收治的60例AMI后行PCI患者作为研究对象。比较患者治疗前后AHEAD评分和超声心动图结果,对超声心动图参数和AHEAD评分绘制ROC曲线,根据AUC探讨各参数的评估效能。结果治疗后1周、1个月、3个月、6个月,患者左心室舒张末期内径(LVEDD)、左心室收缩末期内径(LVESD)均短于前一时间点,左心室短轴缩短率(LVFS)均高于前一时间点,除治疗后3个月与治疗后1个月AHEAD评分比较,治疗后6个月和治疗后3个月左心室射血分数(LVEF)比较差异无统计学意义外,患者治疗前后各时间段LVEF、AHEAD评分两两比较差异均有统计学意义(P<0.05)。ROC曲线分析结果显示,LVESD的评估效能最高,AUC为0.926。结论AHEAD评分联合超声心动图可以较好地评估急性心肌梗死PCI治疗效果和预后。

血清RDW、脑钠肽、HIF-1α及AHEAD评分水平与慢性心力衰竭患者心功能分级、远期死亡结局的关系分析

目的 探讨红细胞分布宽度(RDW)、脑钠肽、缺氧诱导因子1α(HIF-1α)及AHEAD评分与慢性心力衰竭(CHF)患者心功能分级、远期死亡结局的关系。方法 采用前瞻性研究方法,选取2016年1月至2019年1月在海南医学院第一附属医院治疗的CHF患者114例作为观察组,选取同期心功能正常人群100例作为对照组。比较两组RDW、脑钠肽、HIF-1α和血脂水平差异。观察组按照美国纽约心脏病学会(NYHA)分级:Ⅱ级32例,Ⅲ级53例,Ⅳ级29例;随访22~49个月,按照死亡事件发生情况分为死亡患者19例,存活患者95例。同时分析观察组心功能不同NYHA分级、存活和死亡患者RDW、脑钠肽、HIF-1α及AHEAD评分差异。采用受试者工作特征(ROC)曲线分析RDW、脑钠肽、HIF-1α及AHEAD评分预测CHF患者死亡的价值。结果 观察组RDW、脑钠肽和HIF-1α分别为(15.69±1.88)%、544.54(310.54,840.65) ng/L和17.32(9.89,26.65) ng/L,均明显高于对照组,差异均有统计学意义(P<0.05)。随着患者心功能分级升高,患者RDW、脑钠肽、HIF-1α水平以及AHEAD评分≥3分比例升高,差异均有统计学意义(P<0.05),其中心功能分级Ⅳ级患者RDW、脑钠肽、HIF-1α水平以及AHEAD评分≥3分比例分别为(18.12±2.11)%、712.24(589.30,920.22) ng/L、22.54(17.30,30.21) ng/L和93.10%,均明显高于心功能分级Ⅱ级和Ⅲ级患者,差异均有统计学意义(P<0.05)。死亡患者RDW、脑钠肽、HIF-1α水平以及AHEAD评分≥3分比例分别为(17.11±1.92)%、756.03(603.34,1 002.22) g/L、24.40(18.82,33.40) ng/L和89.47%,明显高于存活患者,差异均有统计学意义(P<0.05)。RDW、脑钠肽、HIF-1α及AHEAD评分预测死亡的ROC曲线下面积分别为0.672、0.929、0.894和0.679,P<0.05。结论 随CHF患者心功能分级升高,RDW、脑钠肽、HIF-1α及AHEAD评分水平明显升高,同时在死亡患者中水平较高,其中脑钠肽和HIF-1α在预测远期死亡方面有一定应用价值。

Forecast Error and Predictability for the Warm-sector and the Frontal Rainstorm in South China

In south China, warm-sector rainstorms are significantly different from the traditional frontal rainstorms due to complex mechanism, which brings great challenges to their forecast. In this study, based on ensemble forecasting, the high-resolution mesoscale numerical forecast model WRF was used to investigate the effect of initial errors on a warmsector rainstorm and a frontal rainstorm under the same circulation in south China, respectively. We analyzed the sensitivity of forecast errors to the initial errors and their evolution characteristics for the warm-sector and the frontal rainstorm. Additionally, the difference of the predictability was compared via adjusting the initial values of the GOOD member and the BAD member. Compared with the frontal rainstorm, the warm-sector rainstorm was more sensitive to initial error, which increased faster in the warm-sector. Furthermore, the magnitude of error in the warm-sector rainstorm was obviously larger than that of the frontal rainstorm, while the spatial scale of the error was smaller. Similarly, both types of the rainstorm were limited by practical predictability and inherent predictability, while the nonlinear increase characteristics occurred to be more distinct in the warm-sector rainstorm, resulting in the lower inherent predictability.The comparison between the warm-sector rainstorm and the frontal rainstorm revealed that the forecast field was closer to the real situation derived from more accurate initial errors, but only the increase rate in the frontal rainstorm was restrained evidently.

Observational and Mechanistic Analysis of a Nighttime Warm-Sector Heavy Rainfall Event Within the Subtropical High over the Southeastern Coast of China

In August 2021,a warm-sector heavy rainfall event under the control of the western Pacific subtropical high occurred over the southeastern coast of China.Induced by a linearly shaped mesoscale convective system(MCS),this heavy rainfall event was characterized by localized heavy rainfall,high cumulative rainfall,and extreme rainfall intensity.Using various observational data,this study first analyzed the precipitation features and radar reflectivity evolution.It then examined the role of environmental conditions and the relationship between the ambient wind field and convective initiation(CI).Furthermore,the dynamic lifting mechanism within the organization of the MCS was revealed by em-ploying multi-Doppler radar retrieval methods.Results demonstrated that the linearly shaped MCS,developed under the influence of the subtropical high,was the primary cause of the extreme rainfall event.High temperatures and humidity,coupled with the convergence of low-level southerly winds,established the environmental conditions for MCS develop-ment.The superposition of the convergence zone generated by the southerly winds in the boundary layer(925-1000 hPa)and the divergence zone in the lower layer(700-925 hPa)supplied dynamic lifting conditions for CI.Additionally,a long-term shear line(southerly southwesterly)offered favorable conditions for the organization of the linearly shaped MCS.The combined effects of strengthening low-level southerly winds and secondary circulation in mid-upper levels were influential factors in the development and maintenance of the linearly shaped MCS.

Comparison of Microphysical Characteristics of Warm-sector,Frontal and Shear-line Heavy Rainfall During the Pre-summer Rainy Season in South China

Warm-sector heavy rainfall(WR),shear-line heavy rainfall(SR),and frontal heavy rainfall(FR)are three types of rainfall that frequently occur during the pre-summer rainy season in south China.In this research,we investigated the differences in microphysical characteristics of heavy rainfall events during the period of 10-15 May 2022 based on the combined observations from 11 S-band polarimetric radars in south China.The conclusions are as follows:(1)WR has the highest radar echo top height,the strongest radar echo at all altitudes,the highest lightning density,and the most active ice-phase process,which suggests that the convection is the most vigorous in the WR,moderate in the FR,and the weakest in the SR.(2)Three types of rainfall are all marine-type precipitation,the massweighted mean diameter(Dm,mm)and the intercept parameter(Nw,mm^(-1) m^(-3))of the raindrops in the WR are the largest.(3)The WR possesses the highest proportion of graupel compared with the FR and SR,and stronger updrafts and more abundant water vapor supply may lead to larger raindrops during the melting and collision-coalescence processes.(4)Over all the heights,liquid and ice water content in the WR are higher than those in the SR and FR,the ratio of ice to liquid water content in the WR is as high as 27%when ZH exceeds 50 dBZ,definitely higher than that in the SR and FR,indicating that the active ice-phase process existing in the WR is conducive to the formation of heavy rainfall.

Comparison of Microphysical Characteristics Between Warm-sector and Frontal Heavy Rainfall in the South of China

During the April-June raining season,warm-sector heavy rainfall(WR) and frontal heavy rainfall(FR) often occur in the south of China,causing natural disasters.In this study,the microphysical characteristics of WR and FR events from 2016 to 2022 are analyzed by using 2-dimensional video disdrometer(2DVD) data in the south of China.The microphysical characteristics of WR and FR events are quite different.Compared with FR events,WR events have higher concentration of D<5.3 mm(especially D <1 mm),leading to higher rain rates.The mean values of Dmand lgNwof WR events are higher than that of FR events.The microphysical characteristics in different rain rate classes(C1:R~5-20 mm h-1,C2:R~20-50 mm h-1,C3:R~50-100 mm h^(-1),and C4:R> 100 mm h^(-1)) for WR and FR events are also different.Raindrops from C3 contribute the most to the precipitation of WR events,and raindrops from C2 contribute the most to the precipitation of FR events.For C2 and C3,compared with FR events,WR events have higher concentration of D <1 mm and D~3-4.5 mm.Moreover,the shape and slope(μ-A) relationships and the radar reflectivity and rain rate(Z-R) relationships of WR and FR events are quite different in each rain rate class.The investigation of the difference in microphysical characteristics between WR and FR events provide useful information for radar-based quantitative precipitation estimation and numerical prediction.

Modeling continuous traffic flow with the average velocity effect of multiple vehicles ahead on gyroidal roads

In the future connected vehicle environment,the information of multiple vehicles ahead can be readily collected in real-time,such as the velocity or headway,which provides more opportunities for information exchange and cooperative control.Meanwhile,gyroidal roads are one of the fundamental road patterns prevalent in mountainous areas.To effectively control the system,it is therefore significant to explore the evolution mechanism of traffic flow on gyroidal roads under a connected vehicle environment.In this paper,we present a new continuum model with the average velocity of multiple vehicles ahead on gyroidal roads.The stability criterion and KdV-Burger equation are deduced via linear and nonlinear stability analysis,respectively.Solving the above KdV-Burger equation yields the density wave solution,which explores the formation and propagation property of traffic jams near the neutral stability curve.Simulation examples verify that the model can reproduce complex phenomena,such as shock waves and rarefaction waves.The analysis of the local cluster effect shows that the number of vehicles ahead and the radius information,and the slope information of gyroidal roads can exert a great influence on traffic jams.The effect of the first and second terms are positive,while the last term is negative.

基于IGDT的含广义储能的独立直流微网日前优化调度

微电网的能量管理与优化调度作为构建新型电力系统的重要环节,提高其可再生能源的消纳水平、降低源荷不确定性风险以及优化系统运行成本具有重要意义。因此,文中提出一种基于信息间隙决策理论(information gap decision theory,IGDT)的含广义储能的独立直流微电网日前优化调度模型。首先,构建含超级电容的混合储能系统,以降低蓄电池运行成本,将具备虚拟储能特性的柔性负荷与混合储能相结合,形成广义储能,充分发挥微电网系统内灵活性资源特性;其次,考虑系统风光荷不确定性,引入IGDT模型,在确定性模型基础上建立风险规避策略下的鲁棒模型和风险投机策略下的机会模型,从2种决策角度追求降低风险与最大化收益;最后,基于算例仿真分析,证明该调度策略在降低微电网运行成本的基础上可量化不确定性因素对系统调度决策的影响,验证了模型的有效性和可参考性。

考虑源-荷协同风险的水光互补系统日前优化调度

光电高比例渗透阶段会加剧水光互补系统的源-荷协同难度,并引发弃电风险。由此提出一种考虑源-荷协同日前优化调度方法。首先基于波形分段与出力分区提取光伏出力定性特征,引入耦合云生成光电不确定性场景;然后选取波动量、弃电量评价指标建立日前调度模型,采用波形分阶补偿策略保障负荷跟踪能力与控制弃电风险,并编制发电计划;最后根据实际案例的场景集合求解系统实时运行过程。结果表明:耦合云模型能够在波形与出力两个维度模拟不同鲁棒保守度下的光电不确定性;相对于常规确定性优化,考虑源-荷协同日前优化调度方法能够充分发挥水电与水库调节的灵活性,具有更强的风险承担能力,且输电形式满足源-荷协同要求,可以有效规避弃电风险。

计及负荷灵活特性的工业园区综合能源系统日前优化调度研究

研究工业灵活负荷可调特性是提升电网动态调节能力的有效途径。工业园区用户侧存在大量具备调节潜力的工业负荷资源,针对此特性,基于能源集线器构建包含分布式发电系统、储能电站、燃气轮机、燃气锅炉、灵活负荷等在内的工业园区综合能源系统数学模型,并提出一种考虑负荷灵活特性的园区能源系统日前优化调度方法。首先,考虑系统需求响应侧电解铝等灵活性负荷的可平移、可转移、可中断的负荷特性;其次,在计及生产运行要素的基础上,以购能成本、补偿成本以及运行和维护成本之和最小为目标函数,建立系统优化调度模型;最后,基于Matlab软件结合Cplex求解器,并通过3种不同典型场景对比分析,验证了所提模型的有效性。算例分析表明,考虑工业灵活电、热负荷耦合优化,成本最低,比没有灵活负荷参与时的成本降低了6.6%。研究分析表明,工业灵活负荷资源优化配置有助于促进新能源的消纳、减轻工业用电压力和提高工业园区系统运行的经济性。

考虑不确定性的综合能源供应商日前优化运行策略

综合能源供应商作为多能源供应主体,可以参与市场化交易。为探索综合能源供应商在电力市场环境下新的盈利点,构建了考虑需求响应的多主体互动机制,并充分考虑光伏出力、多元用能需求、市场电价以及需求响应资源潜力的不确定性,采用区间优化方法构建了表征综合能源供应商日前运行优化问题的混合整数线性规划模型,得到综合能源供应商的购能、设备运行以及需求响应资源调用等策略。算例验证结果表明,需求响应机制可以有效降低购电成本,增加综合能源供应商的运行收益。

考虑多前车位置及分位数速度差跟驰模型稳定性分析

为探究交通流特性对车辆跟驰行为的影响,基于分位数回归方法对跟驰模型进行改进,通过稳定性分析方法利用车头间距描述交通拥堵情况。根据分位数回归方法对模型中的优化速度函数进行改进,并将其应用于考虑多前车位置及速度差跟驰模型,使模型可以通过分位点的变换,在仿真过程中模拟不同驾驶风格的车辆。运用傅里叶变换理论推导出该模型的线性稳定性条件,并通过摄动法求得其修正Korteweg-de Vries(mKdV)方程的解,根据车头间距的扭结-反扭结解描述交通拥堵的变化情况。分析对比考虑不同因素的跟驰模型的稳定性临界曲线,为评估改进模型的有效性,搭建环形车道仿真平台并对改进模型进行数值实验。结果表明:在仿真实验中,随着分位点的增加,改进模型达到稳定状态的平均速度逐渐增加,车速分别为9.57、12.58、14.76 m/s;相比原模型,改进模型能够实现更少的位移波动,位移差最小为1.05 m;在混合模型实验中,随着激进驾驶风格车辆数量的增加,改进模型与多速度差模型相比,车队整体的平均速度达到12.42 m/s,位移波动能够达到稳定状态。

计及需求响应潜力的电动汽车聚合商多主体日前投标策略

针对电动汽车这一新型储能资源大规模接入后电力市场多主体竞争格局,提出一种计及需求响应潜力的电动汽车聚合商多主体日前投标策略。以实现削峰填谷、保障电网安全稳定运行等为目标,促使电网与聚合商等多方市场主体可持续发展,探索其未来商业模式。首先,根据电动汽车用户出行特性进行电动汽车集群分类,考虑出行时间、到达时间及荷电状态等因素,模拟集群内用户随机充放电选择。结合聚合商整体充电功率上限值与电能波动区间值等主要因素,基于历史数据评估聚合商需求响应潜力。然后,考虑多个聚合商投标问题,建立日前市场投标模型,以测算电动汽车聚合商日前市场效益。为探寻多元竞争格局下最优日前市场投标策略,以日前投标净利润最大为目标函数,考虑电量、功率上限及电池容量等约束条件,利用Gurobi对优化问题进行求解。最后,通过湖北省武汉市某区实际负荷算例验证了所提策略的先进性及可行性。

高比例新能源并网含抽蓄的联合系统变时段日前调度

为提高高比例新能源并网电力系统中火电机组的平稳运行,提出含抽蓄联合系统变时段日前调度策略。首先,根据抽蓄机组的最优调节区间进行净负荷频谱分析,得到其频域下的波动性质;其次,将波动量与高频分量的模糊熵共同作为评价指标,划分为不同调度模式;再次,以系统总成本最小为目标,建立考虑抽蓄最优调节的变时段日前调度模型,确定调度计划;最后,通过算例分析验证所提策略的有效性。

基于上下游市场联动的燃煤电厂两阶段决策模型

随着大宗能源价格大幅波动及新能源上网冲击,作为现阶段不可或缺的燃煤电厂经营举步艰难。对上游燃料采购及仓储成本进行优化管控的同时,对下游电力市场竞价上网进行联动决策,可在一定程度上提高双碳背景下火力发电企业的生存空间。针对上下游市场联动决策周期不一致以及固定发电成本二次曲线无法反映发电成本变动的问题,提出一种基于上下游市场联动的购煤与竞价燃煤电厂两阶段优化决策模型。首先提出燃煤电厂上下游市场的联动模型;其次建立购煤与竞价策略两阶段决策模型,并讨论条件风险价值对决策的影响;最后以燃煤电厂A进行算例分析和两阶段决策模型的有效性验证。算例结果表明,所提两阶段决策模型可以解决上述问题,实现利润最大化。

考虑电动汽车的售电公司日前-日内调度

为充分发挥电动汽车的调度潜力、提高售电公司参与电力市场的竞争力,提出一种考虑电动汽车的售电公司日前-日内优化调度模型。在日前阶段,考虑价格型需求响应方式,售电公司通过购售电价促进电动汽车进行有序充放。售电公司和电动汽车之间构成主从博弈关系。在日内阶段,售电公司采用日内滚动优化方式,对日前计划进行修正,考虑激励型需求响应方式调动电动汽车的灵活性。同时,该模型采用多场景分析法,以考虑风电和负荷预测的不确定性。算例分析结果表明,采用所提出的方法能有效降低售电公司购电成本及电动汽车用电成本,充分发挥电动汽车的调度潜力,降低不平衡成本、弃风率和可中断负荷调用,实现售电公司和电动汽车用户的“双赢”。

基于变时段设计改进多目标差分进化算法的风/光/火/储日前优化调度

在高比例新能源馈入的新型电力系统中,新能源出力的不确定性导致火电难以满足调度计划的精度需求,风/光/火/储系统的经济调度求解算法面临严峻挑战。为此,提出一种基于变时段设计的多目标差分进化算法。首先按各时段负荷特征构建风/光/火/储系统的变时段日前调度规则。进而以系统运行经济成本与污染排放量为目标,基于多目标差分进化算法求解变时段系统日前调度模型的Pareto解集。最后,用IEEE 39节点系统进行测试。结果表明在风、光、储与火电的约束条件均符合校验的情形下,相较于其他算法,该方法使计算结果更加优化,火电机组出力跟踪调度计划效果显著提高,验证了所提方法的有效性。

计及工况预测误差的主动配电网日前无功优化调度策略

为解决工况预测误差较大时,日前无功优化调度方案优化效果不佳的问题,提出了计及工况预测误差的主动配电网日前无功优化调度策略。首先,使用轻量级梯度提升机算法建立日前工况功率预测模型;其次,考虑大规模高比例分布式电源接入主动配电网,以调度时段内所有时间断面的多目标加权累加和为目标函数建立日前无功优化调度模型;最后,设计了一种变寻优粒子空间的改进引力搜索算法对日前无功优化调度模型进行求解,该算法根据历史工况预测误差评价指标调整寻优粒子空间各维度的上下限矩阵,从而抑制了当无功区域内工况预测误差较大时可控设备调度异常的缺陷。最后采用拓展的IEEE 33节点系统算例进行有效性验证。

大倾角钢箱提篮拱桥总体设计

考虑施工技术、经济性和景观效果等方面,陕西蔡家坡渭河特大桥主桥采用(35+210+35) m大倾角钢箱提篮拱桥。该桥采用摩擦摆和环向钢丝绳阻尼支座综合减隔震约束体系,以降低结构的地震响应。拱肋为单室等宽钢箱截面,采用主、副拱肋2条悬链线,主、副拱肋共面,设计为横向内倾20°的大倾角,在提高桥梁景观效果的同时,又有效提高了结构的整体稳定性;拱肋设钢-混结合段连接拱脚与混凝土拱座。桥面系采用自重较轻的正交异性钢桥面板结构。吊杆采用抗拉强度1 860 MPa的环氧柔性钢绞线。基础采用Φ2.5 m的钻孔灌注群桩,以抵抗软弱地质条件下荷载的竖向及水平作用力。该桥总体采用先梁后拱的施工方案。整体及局部有限元分析结果表明,桥梁结构力学性能均满足规范要求,设计安全可靠。

二代高温超导带材失超特性研究

高温超导带材失超会降低其通流能力,从而影响高温超导装置的运行稳定性。目前,高温超导带材失超仿真模型多为二维计算模型,无法准确模拟其失超过程中的电磁热行为。该文采用有限元方法对二代高温超导带材失超特性进行多物理场耦合分析。在三维直角坐标系下,以磁场强度矢量为求解变量,建立了二代高温超导带材失超演化电磁热仿真模型,研究了二代高温超导带材长度方向与宽度方向在不同热扰动工况下的电磁热特性及其演化过程,分析了高温超导带材过电流失超过程中的各层分流状况与超导层电阻率变化行为,区分了不同类型的过电流失超行为,并提出了高温超导带材过电流冲击失超的电阻率判据。