A Comparative Study between Landmark Based and Real Time Ultrasound Guided Sub Arachnoid Block

Background: Sub arachnoid block (SAB) performed by traditional landmark palpation technique can be inaccurate. This problem is exacerbated by altered patient anatomy due to obesity and age-related changes. A pre-procedural ultrasound scan of the lumbar spine has been shown to be of benefit in guiding lumbar epidural insertion in obstetric patients. Information on the use of real-time ultrasound (RUS) guided SAB, to date, been limited. This study compared RUS guided SAB to traditional landmark guided technique in patients undergoing spinal anesthesia for different surgical procedures. Methods: This was a prospective, single center, comparative observational study conducted in the department of anesthesiology at our center. 560 patients who underwent spinal anesthesia either by landmark based technique or real-time ultrasound-guided methods. The primary outcome was the first attempt success rate of dural puncture when employing the two methods. Results: Baseline characteristics were similar in the two study groups. The first attempt success rate of dural puncture in landmark guided group was 64.3% compared to 72.6% in the ultrasound guided group. This difference was not statistically significant. The procedure performance time was significantly shorter with landmark palpation compared to use of real-time ultrasound guided method. Conclusion: Use of RUS-guided technique does not significantly improve the first attempt success rate of SAB dural puncture during spinal anesthesia compared to the traditional landmark-guided technique.

Finite-Time H∞ Control of Switched Nonlinear Systems under State-Dependent Switching

This paper investigates the finite-time H∞ control problem of switched nonlinear systems via state-dependent switching and state feedback control. Unlike the existing approach based on time-dependent switching strategy, in which the switching instants must be given in advance, the state-dependent switching strategy is used to design switching signals. Based on multiple Lyapunov-like functions method, several criteria for switched nonlinear systems to be finite-time H∞ control are derived. Finally, a numerical example with simulation results is provided to show the validity of the conclusions.

Neutronics Optimization of LiPb-He Dual-Cooled Fuel Breeding Blanket for the Fusion-Driven sub-critical System

The concept of the liquid Li17Pb83 and Helium gas dual-cooled Fuel Breeding Blanket (FBB) for the Fusion-Driven sub-critical System (FDS) is presented and analyzed. Taking self-sustaining tritium (TBR >1.05) and annual output of 100 kg or more fissile 239Pu (FBR > 0.238) as objective parameters, and based on the three-dimensional Monte Carlo neutron-photon transport code MCNP/4A, a neutronics-optimizated calculation of different cases was carried out and the concept is proved feasible. In addition, the total breeding ratio ( BR = TBR + FBR ) is listed corresponding to different cases.

On similitude law of sub-systems

Based on Buckingham＇s π-Theorem, dimensional analysis has achieved considerable success over the past near-century. Model testing has long been a powerful tool in both scientific studies and engineering applications. However, the prototype objects are becoming more and more complicated nowadays, and many of the prototype systems can contain several sub-systems. The conventional theories on model-prototype similarity and dimensional analysis have only limited application since the π-Theorem itself does not distinguish between the original system and subsystems. This is particularly true in the field of structural dynamics, where the structure is often modeled as a multi-degree-of-freedom system. In this paper, we attempt to show that, if a system can be decoupled into several nontrivial subsystems, then, in each subsystem, the number of π-terms will be reduced and therefore simplify the model testing. On the other hand, if a system cannot be decoupled into subsystems, then using model testing with reduced π-term analysis, both experimentally and theoretically, may introduce severe errors.

Autoantibodies in Systemic Lupus Erythematosus, on Black African Subject, in Abidjan

Aim: To determine the clinical and immunological characteristics of patients with systemic erythematosus lupus in Abidjan. Patients and Method: We studied 117 patients’ files with systemic lupus erythematosus aged 12 to 73 years old, who fulfilled the American College of Rheumatology (ACR)’s criteria. Antinuclear autoantibodies (ANA) were searched by indirect immunofluorescence. Anti-DNA native autoantibodies, extractable nuclear anti-antigens autoantibodies (anti-Sm, anti-SSA, anti-SSB and anti-RNP) and anti-phospholipids autoantibodies have been searched by ELISA technic. Results: The most frequent clinical manifestations were: articular damages (86.32%), cutaneous and mucosal lesions (71.79%) and fever (76.67%). Kidney damages have been noticed in 40.17%. Neurologic manifestations have been observed in 36.75%. Pericarditis and pleurisies have been noticed in 22.22% and 11.97% of cases, and anaemia in 86.32% of cases. ANA have been detected in 94.12% of cases, anti-DNA native’s autoantibodies in 73.53% and anti-Sm autoantibodies in 75% of cases. Anti-SSA and anti-SSB autoantibodies were respectively in 75% and 56.25% of cases. Anti-RNP autoantibodies were in all the patients, and anti-phospholipids autoantibodies were in 37.50% of cases. Conclusion: Systemic lupus erythematosus of Ivorian black subject is characterised by high prevalence of autoantibodies, mostly Anti-RNP.

Thermo-Dynamical Analysis on Electricity-Generation Subsystem of CAES Power Plant

Besides pumped hydropower, Compressed Air Energy Storage (CAES) is the other solution for large energy storage capacity. It can balance fluctuations in supply and demand of electricity. CAES is essential part of smart power grids. Linked with the flow structure and dynamic characteristic of electricity generation subsystem and its components, a simulation model is proposed. Thermo-dynamical performance on off-design conditions have been analyzed with constant air mass flux and constant gas combustion temperature. Some simulation diagrams of curve are plotted too. The contrast of varied operation mode thermal performance is made between CAES power plant and simple gas turbine power plant.

Frequency of Cardiovascular Risk Factors in Systemic Lupus Erythematosus: A Case-Control Study in a Department of Internal Medicine in Sub-Saharan Africa

Background: The morbidity and mortality of systemic lupus erythematosus are largely due to accelerated atherosclerosis. This is partly related to the high prevalence of traditional cardiovascular risk factors. The aim of our study was to determine the frequency of these factors in lupus patients compared to a control population in a department of internal medicine. Methods: We realized a case-control study in patients with systemic lupus erythematosus according to ACR criteria in 1997. Patients were matched by age and gender with controls subjects without autoimmune disease. We studied the frequency of traditional cardiovascular risk factors in both populations. The study was done in the department of internal medicine of Aristide Le Dantec teaching Hospital, in Senegal, during the period from August 2017 to December 2018. The statistical analysis was performed with SPSS 23.0 software and the level of significance was retained for a p-value Results: We recruited 100 subjects including 50 patients and 50 controls. The mean age was 33.5 ± 11.3 years in cases and 33.3 ± 11.3 years in controls. Dyslipidemia was significantly associated with systemic lupus erythematosus (p = 0.009). Levels of triglycerides (p Conclusion: Traditional cardiovascular risk factors including dyslipidemia and hyperuricemia were more common in patients. Similarly, renal failure was associated with lupus.

Present status and one upgrading method with a cold compressor of the EAST sub-cooling helium cryogenic system

Since 2006, the superconducting toroidal field（TF） coils of the Experimental Advanced Superconducting Tokomak（EAST） have been successfully cooled by supercritical helium at a temperature of 4.5 K and a pressure of 4 bara in eleven experiments. To obtain higher operating currents and magnetic fields it is necessary to lower the operating temperature of the TF coils.The EAST sub-cooling helium cryogenic system, with a warm oil ring pump（ORP）, was tested twice in cool-down experiments, which made the TF coils operate at 3.8 K. However, the long term operational stability of the sub-cooling system cannot be guaranteed because of the ORP＇s poor mechanical and control performance. In this paper, the present status of the EAST subcooling helium cryogenic system is described, and then several cooling methods below 4.2 K and their merits are presented and analyzed. Finally, an upgrading method with a cold compressor for an EAST sub-cooling helium cryogenic system is proposed. The new process flow and thermodynamic calculation of the sub-cooling helium system, and the main parameters of the cold compressor, are also presented in detail. This work will provide a reference for the future upgrading of the sub-cooling helium system for higher operation parameters of the EAST device.

Effect of flow field distribution on the synthesis of sub-micron ZSM-5 molecular sieve in a quasi-solid system

Scale-up synthesis of sub-micron ZSM-5 molecular sieve in a quasi-solid system was investigated. Compared with traditional hydrothermal synthesis, the synthesis in a quasi-solid system has the advantages of high yield, short crystallization time, low energy consumption as well as low emissions. However, the high solid content in the quasi-solid system can cause the mass and heat transfer problems and make scalable production difficult. In order to solve the problem, we have developed a method for the optimization of the mass and heat transfer. By this method one can vary the flow field in the reactor by changing the stirrer speed. Scale-up synthesis of the sub-micron ZSM-5 molecular sieve in a quasi-solid system was carried out in a 5 L reactor with double propeller-type agitators. The process was investigated with product characterization using X-ray diffraction （XRD） and scanning electron microscopy （SEM） and the flow field information was collected using laser Doppler velocimetry （LDV）. The results showed that the flow field patterns can be tuned by using different stirrer speeds, the morphology and size of assynthesized of ZSM-5 can be effectively controlled.

Damping characteristics of friction damped braced frame and its effectiveness in the mega-sub controlled structure system

Based on energy dissipation and structural control principle, a new structural configuration, called the megasub controlled structure （MSCS） with friction damped braces （FDBs）, is first presented. Meanwhile, to calculate the damping coefficient in the slipping state a new analytical method is proposed. The damping characteristics of one-storey friction damped braced frame （FDBF） are investigated, and the influence of the structural parameters on the energy dissipation and the practical engineering design are discussed. The nonlinear dynamic equations and the analytical model of the MSCS with FDBs are established. Three building structures with different structural configurations, which were designed with reference to the conventional mega-sub structures such as used in Tokyo City Hall, are comparatively investigated. The results illustrate that the structure presented in the paper has excellent dynamic properties and satisfactory control effectiveness.

Robust Finite-Time H∞ Filtering for ItôStochastic Systems

This paper investigates the problem of robust finite-time H∞ filter design for Itô stochastic systems. Based on linear matrix inequalities (LMIS) techniques and stability theory of stochastic differential equations, stochastic Lyapunov function method is adopted to design a finite-time H∞ filter such that, for all admissible uncertainties, the filtering error system is stochastic finite-time stable (SFTS). A sufficient condition for the existence of a finite-time H∞ filter for the stochastic system under consideration is achieved in terms of LMIS. Moreover, the explicit expression of the desired filter parameters is given. A numerical example is provided to illustrate the effectiveness of the proposed method.

Delay-Dependent Robust H∞ Control for Uncertain 2-D Discrete State Delay Systems Described by the General Model

This paper considers the problem of delay-dependent robust optimal H∞ control for a class of uncertain two-dimensional (2-D) discrete state delay systems described by the general model (GM). The parameter uncertainties are assumed to be norm-bounded. A linear matrix inequality (LMI)-based sufficient condition for the existence of delay-dependent g-suboptimal state feedback robust H∞ controllers which guarantees not only the asymptotic stability of the closed-loop system, but also the H∞ noise attenuation g over all admissible parameter uncertainties is established. Furthermore, a convex optimization problem is formulated to design a delay-dependent state feedback robust optimal H∞ controller which minimizes the H∞ noise attenuation g of the closed-loop system. Finally, an illustrative example is provided to demonstrate the effectiveness of the proposed method.

Robust Optimal H∞ Control for Uncertain 2-D Discrete State-Delayed Systems Described by the General Model

This paper investigates the problem of robust optimal H∞ control for uncertain two-dimensional (2-D) discrete state-delayed systems described by the general model (GM) with norm-bounded uncertainties. A sufficient condition for the existence of g-suboptimal robust H∞ state feedback controllers is established, based on linear matrix inequality (LMI) approach. Moreover, a convex optimization problem is developed to design a robust optimal state feedback controller which minimizes the H∞ noise attenuation level of the resulting closed-loop system. Finally, two illustrative examples are given to demonstrate the effectiveness of the proposed method.

考虑用电和馈电模式的变流器电驱系统建模与稳定性分析

由大量异步电机驱动设备构成的电力电子化交流配用电系统存在严重的次/超同步振荡问题。电驱系统正常工作时具有用电和馈电2种运行模式,现场振荡现象表明不同的运行模式对系统的稳定性影响也不同。建立了含机侧系统的电驱系统详细阻抗模型,利用阻抗分析法揭示了电驱系统接入电网的次/超同步振荡机理,分析了运行模式、电网强度、控制参数、交流电压幅值等因素对系统次/超同步稳定性的影响,并基于相位裕度灵敏度明确了主导影响因素。基于实际系统数据,搭建了时域仿真模型,仿真复现了振荡现象,并验证了理论分析的正确性。

一次冷涡背景下次天气尺度系统对强对流环境场的影响

在同一东北冷涡背景下,2016年6月12—13日山西境内连续2 d出现强对流天气,12日为分散性对流而13日为大范围强对流。基于多源资料通过对比探讨次天气尺度系统及其演变对风暴环境进而对风暴结构的影响,得出以下结论:(1)两日风暴强度和风暴结构差异显著。6月12日对流孤立分散且回波强度小于55 dBZ,而13日准线性风暴发展成尺度较大的弓形回波引发大范围强对流天气,回波强度达60 dBZ。(2)此次过程的关键影响系统为冷涡背景下的次天气尺度低涡。12日次天气尺度低压扰动开始出现,距离远而未影响山西;13日低压扰动东移发展为次天气尺度切断低涡,低涡相关的地面冷锋及850 hPa切变线触发山西上游对流。(3)12日低层水汽含量低,0~3 km垂直风切变弱,13日低涡前偏南水汽输送使低层显著增湿,叠加中层干冷空气形成不稳定层结,受低涡影响0~3 km风垂直切变增强至5.0×10-3s-1,冷锋触发的对流风暴在上述环境下强烈发展并产生阵风锋,阵风锋组织风暴形成飑线,冷池与0~3 km风切变相互作用使飑线维持。(4)13日有利于飑线发展的环境要素与东北冷涡西侧的次天气尺度切断低涡系统密切相关,次天气尺度低涡是飑线形成发展的关键系统。

Subvolcanic Rock Petroleum System Potential in the South Malang Region, East Java, Indonesia

The South Malang Region is located in the south-eastern part of the Southern Mountain Volcanic Arc;it presents different opportunities for hydrocarbon exploration. The stratigraphy of the study area from old to young consists of Oligocene Volcanic rocks (Mandalika, Watupatok, and Arjosari Formation), Early Miocene Carbonates (Campurdarat and Jaten Formation), Middle Miocene Volcanic (Wuni Formation), Late Miocene-Pliocene Carbonates (Nampol, Oyo, and Wonosari Formation), and Holocene alluvial deposits (Kalipucang Formation). The dominance of volcanic rocks makes this area considered an area without hydrocarbon play prospects. Petroleum system potential is revealed by evaluating and analyzing potential source rock and reservoir rock outcrop samples. The study shows that the Nampol Formation can be considered as a gas-prone source rock, with type III kerogen, total organic content ranging from 3.48 - 26.18 wt%, and possess the potential to produce good to very good hydrocarbons and a hydrogen index ranging from 43 to 86 mgHC/g TOC. Furthermore, rock core analysis and petrographic studies were carried out on the Nampol sandstone where the rock samples showed good reservoir properties. However, the Nampol and Wonosari limestone that was considered as the secondary target for reservoir possesses a low quality of reservoir properties. This study shows that there is a potential for petroleum system existence in the Southern Mountain subvolcanic arc, which is indicated by the presence of source rock and potential reservoir rock as one of the various elements and processes present in a petroleum system.

省以下财政收入体制与财政收入质量:针对非税收入的研究

提高财政收入质量是健全现代预算制度的重要组成部分。理论研究表明,税收分成比例下降会提高非税收入相对规模、降低财政收入质量,且总量费非税收入有一定扭曲效应。经验研究发现,税收分成每下降1个百分点,地方非税收入规模约增加1.27%,财政收入质量约降低2.02%,这表明财政收入分配体制是影响非税收入规模的重要制度要素。异质性分析表明,国有化程度低和非税收入管理规范的地区非税收入规模变化较小,而提高财政资金审计质量和强化法制化建设有利于提高财政收入质量。本文为提高财政收入质量、建设现代财政制度提供了一定参考。

新型冠状病毒感染呼吸亚重症病房建设及运行模式探讨

随着我国新型冠状病毒感染防控措施的不断优化和调整,临床医疗工作重心逐步向“保健康、防重症”转移。为了提升危重症患者的救治能力,北京大学第三医院改造了21个亚重症病房,打破科室、专业壁垒,进行统筹协调。文章介绍了呼吸亚重症病房的实施路径和制度建设,总结了相关经验和成效,对平战结合联合病房管理模式进行了思考。

多频段共口径遥感信号接收天伺馈系统设计

针对多频段遥感信号接收系统对S/C/X/Ku/Ka五频段信号共口径接收、高精度指向和全空域过顶稳定跟踪需求,研制了一种多频段遥感信号接收天伺馈系统,解决了天线多频段共口径接收和波束窄、信号难捕获跟踪的技术难题。提出并采用“频率选择副面+旋转”换馈方式、高精度筋开槽微应力胶粘面板、时间最优的非线性多模自适应跟踪控制技术,实现了多频段信号高可靠共口径接收和高精度指向及稳定过顶跟踪。对塔测试结果表明,所设计的多频段共口径接收天伺馈系统具有优良的性能,天线增益、第一旁瓣电平、差波束零深、跟踪精度和指向精度等各项指标均满足指标要求;对星动态跟踪测试表明,Ka频段指向均方根误差优于0.0136°,Ka频段跟踪方位均方根误差优于0.0056°,俯仰均方根误差优于0.0045°。验证了所提天伺馈系统设计的有效性,可用于指导多频段大口径遥感接收天伺馈系统设计。

Application of the Sub-Model Method in the Engine Strength Analysis

On the basis of introducing the fundamental theory and the basic analysis steps of the sub model method, the strength of the new engine complex assembly structure was analyzed according to the properties of the engine structures, some of the key parts of the engine were analyzed with refined mesh by sub model method and the error of the FEM solution was estimated by the extrapolation method. The example showed that the sub model can not only analyze the comlex structures without the restriction of the software and hardware of the computers, but get the more precise analysis result also. This method is more suitable for the strength analysis of the complex assembly structure.