Hepatic encephalopathy complicated with hyponatremia and acid-base disturbance and its prognosis

Objective:To improve the diagnosis and therapeutic effect of occurrence and development of hyponatremia and disorder of acid-base balance among patients with hepatic encephalopathy(HE) by elucidating the regularity and mechanism,as well as its influence on prognosis.Methods:327 HE patients admitted to our hospital from January 1990 to June 2010 were enrolled.Meanwhile 316 patients hospitalized in the medical department of the same hospital were chosen as the control group.Patients in both groups were given the same methods to measure arterial blood gas parameters(pH value,PaCO2,[HCO3-],TCO2,BE and SaO2),blood biochemistry([Na+],[K+],[Cl-]),liver function,kidney function and blood glucose,serum sodium,and thereupon tocalculate the anion gap(AG) and the potential [HCO3-],and acid-base balance disorder.Results:Among the 327 HE patients,hyponatremia was found in 188 cases(57.4%),of whom 132 patients died(70.2%).While among the 316 patients in control group,68 presented with hyponatremia(21.5%),and 19 died(27.9%).The incidence and mortality were significantly different between the two groups(P<0.001).All the 327 patients presented with different degrees of acid-base balance disorder and 178 died(54.4%),in whom 164(50.2%) belonged to simple acid-base balance disorder and 74(45.1%) died,136(41.6%) were dual acid-base balance disorder and 80(58.8%) died,27(8.2%) were triple acid-base disturbance and 24(88.9%) died.Whereas in the control group only 83 patients(26.2%) were recognized as simple and dual acid-base balance disorder,and 18(21.7%) died.There was higher incidence of acid-base balance disorder and mortality rate in HE group than control one(P<0.001).Conclusion:Hyponatremia is valuable to judge HE patients' prognosis.The key parameters in the judgment and evaluation on acid-base balance disorder among HE patients are the change of pH values and serum electrolyte values.When pH value ≤ 7.30 or > 7.55,it generally suggests a poor prognosis.

Robust Tracking Control for Self-balancing Mobile Robots Using Disturbance Observer

In this paper,a robust tracking control scheme based on nonlinear disturbance observer is developed for the self-balancing mobile robot with external unknown disturbances.A desired velocity control law is firstly designed using the Lyapunov analysis method and the arctan function.To improve the tracking control performance,a nonlinear disturbance observer is developed to estimate the unknown disturbance of the self-balancing mobile robot.Using the output of the designed disturbance observer,the robust tracking control scheme is presented employing the sliding mode method for the selfbalancing mobile robot.Numerical simulation results further demonstrate the effectiveness of the proposed robust tracking control scheme for the self-balancing mobile robot subject to external unknown disturbances.

Knowledge Law and Attribute Disturbance of Law

By employing the knowledge（R-element equivalence class） in one direction S-rough sets and dual of one direction S-rough sets, the concept of knowledge law is given; the generation theorem of knowledge law, the excursion theorem of knowledge law, and the attribute disturbance discernible theorem of knowledge law are proposed. Knowledge law is a new characteristic of S-rough sets.

Study on acid-base disorders in patients with adult respiratory distress syndrome

Arterial blood gases and electrolytes were determined in 159 cases of adult respirato-ry distress syndrome(ARDS).It was found that disordered acid-base balance was a commonfinding in various kinds of ARDS.In mild ARDS,respiratory alkalosis and the combination ofrespiratory alkalosis plus metabolic alkalosis or metabolic acidosis were usually encounted,whilein moderate and severe cases of ARDS,triple acid-base disorders,respiratory acidosis,and thecombination of respiratory acidosis plus metabolic acidosis were commonly seen.Severe alkalosiswas one of the factors to result in death.

A STUDY ON ACID-BASE DISTURBANCE IN PATIENTS WITH POST-TRAUMATIC MULTIPLE ORGAN FAILURE

In order to diagnose accurately the type of acid梑ase disturbance (ABD) in patients with post梩raumatic multiple organ failure (PMOF), arterial blood gases and electrolytes were determined 645 times on 112 patients with PMOF and the data were analyzed with the pre-estimated compensatory formula of ABD and the calculations of anion gap, potential bicarbonate, and blood chlorides. Simple ABD was found in 381 times of determinations and double ABD in 239 when only the formula was used in the analysis, while 264 times of simple ABD, 260 times of double ABD and 96 times of triple ABD were found when the formula was employed in combination with the calculations of anion gap, potential bicarbonate and blood chloride. The mixed types of ABD were increased by 49% (117 times) from 239 to 356 times and triple ABD was increased from 0 to 96 times. The findings indicate that the employment of the combined formula and the calculations of anion gap, potential bicarbonate and blood chloride is of great significance to assess ABD especially its mixed and complicate types in patients with PMOF. It is emphasized that along with the monitoring of blood gases, the determination of blood electrolytes and the calculation of anion gap and potential bicarbonate should be performed to determine the correct type of ABD.

Recent advances in selective C–C bond coupling for ethanol upgrading over balanced Lewis acid-base catalysts

Ethanol is a considerable platform molecule in biomass conversion,which could be acquired in quantity through acetone-butanol-ethanol(ABE)fermentation.People have been working on the upgrading of ethanol to value added chemicals for decades.In the meantime,1-butanol and a series of value added products have been selectively generated through C–C bond coupling.In this mini-review,we focus on the recent advances in selective C–C bond formation over balanced Lewis acid-base catalysts such as modified metal oxide,mixed metal oxide,hydroxyapatite and zeolite confined transition metal oxide catalysts.Among them,Pd-MgAlO_x and Sr-based hydroxyapatite exhibit>70%1-butanol selectivity,while Zn——xZr_yO_z and Ta-Si BEA zeolite achieve>80%of isobutene and butadiene selectivity respectively.The mechanism and reaction pathway of C–C bond formation in each reaction system are described in detail.The correlation between C–C bond coupling and the acidity/basicity of the Lewis acid-base pairs from the surface of the catalysts are also discussed.

Therapeutic Effect Observation on Treatment of Vestibular Central Balance Disturbance with Brain-Regulating Electroacupuncture

Objective.To investigate the therapeutic effect of electroacupuncture on vestibular central balance disturbance. Methods： Forty-six patients with vestibular central balance disturbance were randomly divided into a treatment group of 23 cases and a control group of 23 cases. After 4 weeks treatment, the effects were evaluated by Berg balance scale, Visual analog scale and a staticdynamic balance test. Results. The effective rate was 87.0% in the treatment group and 65.2% in the control group. There was a significant difference （P〈 0.05）. After treatment, Berg balance scale score, eye opening with two feet standing time and eye closure with two feet standing time were better in the treatment group than in the control group after treatment （P〈 0.05）. Conclusion. This therapy is effective for vestibular central balance disturbance.

背压扰动平衡盘对涡旋压缩机黏性内流压力影响研究

在变转速工况下,电动涡旋压缩机背压腔中润滑油产生的背压力无法准确平衡轴向气体力。针对这一问题,提出了一种带有扰动片的背压扰动平衡盘,研究了背压扰动平衡盘对涡旋压缩机黏性内流压力的影响。首先,对背压扰动平衡盘作用原理进行了分析,使用贝塞尔曲线构建了扰动片型线,对润滑油被扰动后的静压增量进行了公式推导,计算了扰动片出口安装角和扰动片数对润滑油静压的影响;然后,建立了含背压扰动平衡盘的背压腔模型,将流体域分为旋转域和静止域,采用旋转坐标系的方法进行了数值模拟,研究了背压腔内润滑油的压力场;最后,根据理论计算,模拟了润滑油在不同出口安装角和扰动片数下的润滑油静压,对润滑油静压与压缩机所需最佳背压进行了对比分析。研究结果表明:采用背压扰动平衡盘可以使润滑油静压增加21%,且静压增量随主轴转速的增加而增大,适当增大扰动片出口安装角可使润滑油静压增加0.032 MPa;对比最佳背压可知,扰动前润滑油静压与最佳背压相差26%,而合理设计扰动片后的润滑油静压与最佳背压相差仅为9%,极大改善了电动涡旋压缩机在变转速下的轴向平衡。

引入负载扰动观测的Boost变换器定频滑模控制

针对传统线性控制方法下Boost变换器存在系统动态性能差和对负载扰动鲁棒性不强的问题,从功率平衡的角度提出1种定频滑模电流控制方法。首先,利用负载电流观测值计算维持输出电压稳定所需的输入功率;其次,通过控制电感电流调整变换器输入功率,从而将系统的状态轨迹限制在对负载扰动具有不变性的滑模面上,保证系统大信号稳定并提升其动态性能;最后,基于等效控制原理,通过PWM技术实现等效滑模控制,避免了传统滑模控制中存在的抖振及开关频率不稳定问题。在Simulink中对Boost变换器负载阶跃变换的工况进行仿真,将所提方法与传统线性控制方法对比。结果表明,采用所提方法,系统的动态性能更好,且能保证系统在负载大范围扰动下的大信号稳定。

血尿酸、酸碱平衡紊乱及其交互作用在慢阻肺免疫功能下降中的作用研究

目的探讨血尿酸(Serum Uric Acid,SUA)、酸碱平衡紊乱及其交互作用对慢性阻塞性肺疾病(Chronic Obstructive Pulmonary Disease,COPD)患者免疫功能下降的影响。方法选取2022年10月—2023年10月钦州市第二人民医院收治的223例COPD患者为研究对象。根据患者是否出现免疫功能下降分为免疫功能下降组(n=67)和免疫功能正常组(n=156)。比较两组的SUA水平、血氧分压(Partial Pressure of Oxygen,PO_(2))、二氧化碳分压(Partial Pressure of Carbon Dioxide,PCO_(2))、碳酸氢根离子和碱剩余(Base Excess,BE),分析SUA和酸碱平衡指标之间的交互作用。结果两组PO_(2)、PCO_(2)、碳酸氢根离子和SUA水平比较,差异有统计学意义(P均<0.05)。PO_(2)、PCO_(2)、碳酸氢根离子、SUA均为COPD患者免疫功能下降的影响因素(OR=2.484、2.554、2.891、5.757,P均<0.05);碳酸氢根离子与SUA存在相加交互作用,但未发现存在相乘交互作用;PO_(2)、PCO_(2)与SUA均不存在相加、相乘交互作用。结论SUA、PO_(2)、PCO_(2)和碳酸氢根离子是COPD患者免疫功能下降的影响因素,并且SUA和HCO3存在相加交互作用,各因素之间无相乘交互作用。

基于自适应特性的直流微电网双因子下垂控制策略研究

分布式电源DG(distributed generator)出口线路参数不一致及其出力随机扰动引起了直流微电网负荷功率分配精度下降与网侧电压波动。针对上述问题,计及DG运行暂稳态工况,提出1种基于自适应特性的双因子下垂控制策略。首先,稳态运行时考虑线路阻抗的影响并引入电压调节系数,建立双因子下垂系数稳态分量,在阻抗值未知的情况下即可实现负荷功率的精确分配,同时抬升网侧电压,减小与额定电压的差值;其次,暂态过程中考虑DG出力随机扰动的影响并引入分布一致性迭代算法,建立双因子下垂系数自由分量,可在维持DG均衡出力的情况下快速抑制功率扰动与网侧电压波动,提高系统的稳定性;最后,在PSCAD中搭建直流微电网模型,仿真结果证明了所提策略的有效性。

考虑负载均衡的配电台区柔性互联系统大扰动稳定性分析

柔性互联系统具有潮流控制灵活、供电可靠性高等优点,已逐渐成为提升配电台区供电水平的解决方案。为应对当前配电台区难以扩容,无法有效利用台区容量等问题,提出了考虑负载均衡的直流电压-交流源功率(vdc-Pgrid)下垂控制策略,使正常运行时各台区交流源出力均衡。将台区等效为受控电流源,建立了系统的简化电路模型。基于混合势函数理论分析了直流母线接入恒功率负载时系统的大扰动稳定性,并得到系统的稳定判据。通过硬件在环实验,验证了所提控制策略的有效性和所得稳定判据的准确性。

基于干扰观测器的级联H桥STATCOM相间电压平衡控制

针对级联H桥STATCOM在复杂工况下电网电压跌落和不平衡引起的相间电容电压不平衡问题,提出了基于干扰观测器DOB的前馈控制。通过研究级联H桥STATCOM的功率分布状况,分析了级联H桥STATCOM相间不平衡原因,将负序功率视为扰动进行负序功率前馈,并考虑模型差异以及各种干扰引起的偏差影响,根据交流侧与直流侧有功功率交换情况,将直流功率经DOB观测后前馈至相间电压平衡控制的输出端,以零序功率注入实现级联H桥STATCOM相间电压平衡控制。最后在Matlab/Simulink建立了级联H桥STATCOM仿真模型,仿真结果验证了在复杂工况下,该控制策略能够提升系统相间电压平衡的快速性、跟随性和鲁棒性。

基于自抗扰解耦的电力电子牵引变压器整流级直接功率控制

【目的】为改善电力电子牵引变压器(PETT)整流级在传统dq电流解耦双闭环控制下抗干扰能力差、对参数变化敏感、谐波含量高等问题。【方法】通过对直接功率控制(DPC)的解耦方式进行改进,提出了一种无需系统角频率和电感参数基于自抗扰控制(ADRC)的功率解耦控制器。最后,在Matlab/Simulink中搭建模型进行不同工况的仿真分析。【结果】仿真结果表明新型控制策略较传统控制策略网侧电流THD值减少5.38%,等效电感突变时电压跌落值减少48 V,电压频率偏移时电压跌落值减少14 V,新型控制策略在负载突变和负载不平衡工况下具有较好的平衡控制效果。【结论】该控制器通过解耦实现了有功功率和无功功率精确且独立的控制。仿真结果验证了所提控制策略的合理性与有效性。

自行车机器人滑模变结构控制器设计与实现

协调的运动控制方案对于智能无人机器人精确稳定的运动至关重要。针对反作用力轮无人自行车的独立平衡问题,提出一种固定时间收敛结合自适应干扰补偿的高阶滑模控制方案。该方案可普遍应用于考虑了幅度和速率约束的执行器等一类问题。首先,出于整体设计考虑,采用固定时间快速收敛的滑模控制器进行反作用力轮无人自行车功率驱动,同时设计一个高阶滑模干扰观测器补偿未建模参数项和外部干扰的影响;其次,基于Lyapunov函数给出闭环控制系统的稳定性证明。在实际场景中进行验证实验,所提方案相较其他滑模控制方法有5%~30%幅度的性能提升,特别是在动态行驶误差RMSE方面达到了0.003 1 rad,说明控制器在行驶过程中稳定有效。

半圈闭深循环基岩热储开采扰动分析及回灌方案研究

聊城东热田奥陶系热储为山东省基岩热储勘探开发优选区,本文通过分析区内盖储源通等地热特征建立了区域半圈闭深循环裂隙-岩溶基岩热储模型,分析认为其半圈闭深循环赋存特征在提升热水矿化度及微量元素的同时,导致了储层封闭性较强、开采扰动大、难以可持续利用等问题。基于区内观测井多年实测数据建立了开采降深经验公式,采用变异系数法及综合指数法对区内热储开采扰动性进行评价,认为区内基岩热储开采导致了水位下降、水量减少、储层压力、温度及使用寿命降低等不利影响,对水质的扰动性及地面沉降、热污染、环境污染、串层水源污染等开采次生问题较少;结合区内回灌试验,探讨了适宜本地的开采回灌方案:集中开采、梯度利用、同层回灌、采灌均衡,区内基岩热储回灌井宜设置在开采井周边300-500 m范围内,尾水温度以35-40℃为宜。本次研究为区内基岩热储的可持续利用提供了理论依据。

引入自抗扰控制的MMC均压环流简化控制策略

针对模块化多电平换流器(MMC)正常工作时,子模块电容电压不平衡和三相桥臂间存在环流分量的问题,通过引入自抗扰控制,提出一种新的均压环流控制策略。分析子模块电容电压波动以及环流机理,提出基于自抗扰控制的单环子模块均压控制;结合二阶广义积分器滤波环节提取交流分量,使用准PR控制对环流二倍频分量进行抑制。在稳态、动态条件下进行实验,结果表明:在稳态条件下,基于ADRC的单环控制波动系数降低0.5%,环流抑制降低19%,输出电流畸变率降低0.46%;在动态条件下,可以快速达到新的稳定状态,对电容电压脉动有良好的抑制作用。

基于线性自抗扰控制的单相电力电子变压器整流级控制策略

针对电力电子变压器的非线性特性,传统PI控制的单相电力电子变压器整流级具有对参数变化敏感,响应速度慢,抗扰性能差的特点。提出了一种基于线性自抗扰控制(line active disturbance rejection control,LADRC)的电压环控制策略,该控制策略具有响应速度快、超调量小、鲁棒性强的特点。在仿真软件MATLAB/Simulink中通过搭建三级联H桥整流器模型进行仿真,并与传统PI控制器相比较,仿真结果表明所采用控制策略的优越性、有效性。

基于滚球倒立摆模型对新型自平衡车载人研究

针对自平衡车制动性能差、抗干扰能力弱等问题,设计了一种新型自平衡车,利用滚球倒立摆模型研究新型自平衡车载人运动过程。构建动力学模型,基于PID控制方法论证了设计方案的可行性;基于自抗扰控制技术改进控制系统,使用Simulink进行仿真并与实验数据对比分析。结果表明,新型自平衡车在较大加速度(15 m/s^(2))时仍能保持稳定,动态品质较高。

双极性直流微电网中多电压平衡器协调控制

针对应用电压平衡器来解决双极性直流微电网正、负极对中线电压的平衡控制问题,提出一种基于下垂控制和干扰观测器相结合的多电压平衡器并联运行与协调控制方法。应用干扰观测器,能在不需要增加额外电流传感器的情况下,利用本地测量信息即可实现对电压平衡器输出电流的快速跟踪;采用基于干扰观测器输出结果的外环直流电压下垂控制和内环输出电流前馈控制,不仅能实现在无互联通信情况下的多电压平衡器并联运行和即插即用,还能有效提高直流电压平衡控制系统的动态响应,抑制双极性直流微电网内负荷突变、间隙性分布式电源出力波动等暂态对直流母线正、负极对中线电压的冲击。最后,在包含直流模拟电源、两台电压平衡器以及相应阻性负荷、恒功率负载等构成的双极性直流微电网实验平台中验证了所提方法的有效性。