指压降压法在青光眼持续性高眼压手术时的疗效观察

对26例（31眼）术前用降眼压药不能控制的青光眼持续性高眼压患者，行抗青光眼手术时于球后麻醉后采用指压降压法。结果：眼压均可降至正常，并能顺利进行小梁切除或联合晶体摘除手术，术后并发症少。平均随访16．7个月，90％的患者眼压正常，80％的病人视力较术前提高。因此，对青光眼持续性高眼压用降眼压药效果不佳的患者，应尽早用此方法施行抗青光眼手术治疗。

福清核电厂1、2号机组安全壳整体泄漏率试验充压和降压速率优化的分析和研究

福清核电厂1、2号机组安全壳整体泄漏率试验在换料大修期间进行并作为大修关键路径的主线工作,而安全壳整体泄漏率试验的充压和降压速率是影响主线工作的重要因素。为提高机组的可利用率和经济性,基于法规和标准的要求,结合同类型机组的经验反馈对安全壳整体泄漏率试验进行优化,分析和研究试验中充压和降压速率提升的可行性。

SW-50型PSM短波广播发射机升降压控制原理及常见故障

SW-50型50kW短波广播发射机是PSM调制的发射机高末屏压控制涉及多个控制信号,和功能单元,控制架构比较复杂,出现故障不容易判断原因,给快速处理造成一定困难。本文从PSM调制原理角度,结合实际案例,解构屏压控制,分析其所涉及的功能单元,理清处理此类故障的思路,对于该设备的维护与营运管理具有一定的指导意义。

SW-50型PSM短波广播发射机升降压控制原理及常见故障

SW-50型50kW短波广播发射机是PSM调制的发射机高末屏压控制涉及多个控制信号,和功能单元,控制架构比较复杂,出现故障不容易判断原因,给快速处理造成一定困难。本文从PSM调制原理角度,结合实际案例,解构屏压控制,分析其所涉及的功能单元,理清处理此类故障的思路,对于该设备的维护与营运管理具有一定的指导意义。

深井开采水力压裂技术参数确定与应用

为了解决抽放钻孔施工过程中垮孔及瓦斯预抽困难的问题,以石壕煤矿为工程背景,采用现场实测、数值模拟、现场应用等手段,对水力压裂技术进行扩展应用,对于揭煤局部范围采取井组压裂技术,对于瓦斯重灾区采取拦截降压压裂技术。通过数值模拟不同水压下钻孔渗透率变化,确定井组压裂与拦截降压压裂施工参数,进行工程应用。研究结果表明,通过实施井组压裂技术,煤层渗透性增加,在抽采负压相同的情况下,单孔瓦斯浓度均较高,与未实施井组压裂的地点相比,压裂钻孔单孔初抽浓度高、瓦斯量多。通过实施拦截降压压裂技术,使压裂区域的瓦斯压力得到释放,垮孔现象降低,解决了喷孔造成瓦斯高浓度超限问题,该研究为深部矿井开采瓦斯防治提供了新途径。

细粉在锥形床中流态性能的研究

文中主要介绍Geldart-A颗粒在三种不同锥角的锥形流化床 ,随着气体表观速度的增加 ,呈现出两种不同的流化区域 ,即固定床和喷动床。由于部分流化床区域的消失 ,所以Gel dart-A流态化状态特征不同于Geldart-D颗粒的状态特征。

对于电缆接地故障定位方法的探讨

在南埔电厂二期600MW机组扩建工程循环水泵试运过程中,发生的循泵电缆低阻接地故障,通过对本次故障的处理所总结出来的简易快捷的探测及定位电缆接地故障的方法,为以后出现类似电缆故障提供了理论依据。

Improvement of Electrical Performance of SOI-LIGBT by Resistive Field Plate

The electrical performance including breakdown voltage and turn-off speed of SOI-LIGBT is improved by incorporating a resistive field plate (RFP) and a p-MOSFET.The p-MOSFET is controlled by a signal detected from a point of the RFP.During the turning-off of the IGBT,the p-MOSFET is turned on,which provides a channel for the excessive carriers to flow out of the drift region and prevents the carriers from being injected into the drift region.At the same time,the electric field affected by the RFP makes the excessive carriers flow through a wider region,which almost eliminates the second phase of the turning-off of the SOI-LIGBT caused by the substrate bias.Faster turn-off speed is achieved by above two factors.During the on state of the IGBT,the p-MOSFET is off,which leads to an on-state performance like normal one.At least,the increase of the breakdown voltage for 25% and the decrease of the turn-off time for 65% can be achieved by this structure as can be verified by the numerical simulation results.

The Effects of Acupuncture on Blood Pressure in Different Patients

Eighty-seven patients with different types of diseases were treated with acupuncture,and the changes of their blood pressure were investigated.The results showed that the total level of systolic pressure in the 87 cases decreased (P<0.05).Especially,the systolic pressure in patients accompanied with hypertension decreased significantly.It is suggested that when acupuncture is adopted to treat other diseases,it can decrease the systolic pressure to a certain extent in patients accompanied with hypertension,but it does not exert significant influence on both systolic and diastolic pressure in patients with normal blood pressure.

Analysis and Design of a High-Stability,High-Accuracy,Low-Dropout Voltage Regulator

A high-accuracy,low-dropout （LDO） voltage regulator is presented. Using the slow-rolloff frequency compensation scheme, the LDO effectively overcomes the stability problem, facilitates the use of a ceramic capacitor, and improves the output voltage accuracy, which is critical for powering high-performance analog circuitry. The slow-rolloff compensation scheme is realized by introducing three pole-zero pairs, including the proposed polezero pair and sense zero. The post-layout simulation results demonstrate that this LDO has robust system stability, a high open-loop gain, and a high unit-gain frequency,which lead to excellent regulation and transient response performance. The line and load regulation are 27μV/V and 3.78μV/mA, and the overshoots of the output voltage are less than 30mV,while the dropout voltage is 120mV for a 150mA load current.

A Clinical Study on Haunglian Fire-Purging Mixture In Treatment of 46 Cases of Primary Hypertension

In order to observe the therapeutic effects of Huanglian Fire-Purging Mixture (黄连清降合剂) on primary hypertension, 46 cases of primary hypertension in the treatment group were treated with Huanglian Fire-Purging Mixture to clear away heat from the liver, relieve mental stress, purge fire and remove toxin;and the other 26 cases of primary hypertension in the control group were treated with Niuhuang Bolus for Lowering Blood Pressure (牛黄降压丸). The effect in the treatment group was obviously superior to that in the control group (P＜0.05). The Huanglian Fire-Purging Mixture shows noticeable effects 3-6 hours after medication. The mixture can improve the clinical symptoms, the left ventricular diastolic function and myocardial ischemia, correct dyslipoproteinemia and dysglycemia, and reduce blood viscosity. And it is safe and with no obvious adverse reactions.

Studies on a New Random Packing—Plum Flower Mini Ring

The hydrodynamics and mass transfer of Plum Flower Mini Ring (PFMR), Pall Ring and Intalox Saddle were studied in a 600 mm diameter column with air-oxygen-water system over a wide range of liquid loads. It was shown from the experiments that PFMR had much lower resistance, larger throughput and higher mass transfer efficiency than Pall Ring and Intalox Saddle. It was clear from the comparison that existing equations could not predict the performance of packings very well at high liquid loads. Therefore, new semi-empirical equations of pressure drop, flooding gas velocity and height of transfer unit (HTU) were proposed based on the experimental data.

Pressure Drop Measurements on Distillation Columns

Pressure drops are of major importance for distillation/absorption columns. This paper mainly discusses how to correctly measure, interpret and use pressure drop data. The possible causes of incorrect pressure drop measurements are studied including the effects of pressure tap dimensions, locations, and vapor condensation etc. The effect of the static head of vapor on the pressure drop data and column pressures is evaluated. Variations of sectional pressure drops along the column are investigated based on the experimental data obtained from commercial size distillation columns at Fractionation Research, Inc. （FRI）. For a packed column, it is found that the spacing between the liquid distributor and the top of the bed affects the overall pressure drop measurements, which is confirmed by a fundamental fluid dynamics analysis.

Effect of extrusion parameters on degradation of magnesium alloys for bioimplant applications:A review

Magnesium alloys,as a new generation temporary biomaterial,deserve the desirable biocompatibility and biodegradability,and also contribute to the repair of the damaged bone tissues.However,they do not possess the required corrosion resistance in human body fluid.Hot mechanical workings,such as extrusion,influence both the mechanical properties and bio-corrosion behavior of magnesium alloys.This review aims to gather information on how the extrusion parameters(extrusion ratio and temperature)influence the bio-corrosion performances of magnesium alloys.Their effects are mainly ascribed to the alteration of extruded alloy microstructure,including final grain size and uniformity of grains,texture,and the size,distribution and volume fraction of the second phases.Dynamic recrystallization and grain refinement during extrusion provide a more homogeneous microstructure and cause the formation of basal texture,resulting in improved strength and corrosion resistance of magnesium alloy.Extrusion temperature and extrusion ratio are reported as the influential factors in the degradation.The reports reveal that the increase in extrusion ratio and/or the reduction in extrusion temperature cause a decrease in the final grain size,leading to intensification of basal texture,in parallel side of the samples with extrusion line,and to lower volume fraction and size of precipitates in magnesium alloys.These all lead to improving the bio-corrosion resistance of the magnesium alloy implants.

Pressure-relief and permeability-increase technology of high liquid–solid coupling blast and its application

As for the coal seam with high stress,high gas and low permeability,a single technology cannot prevent the complex dynamic disasters.Because of this,the study proposes a new method of pressure-relief and permeability-increase technology of the high liquid–solid coupling blast.Through coal seam injection and charging structure change,the paper fully works out the dual functions of the water and explosion.Using the theoretical calculation,numerical simulation and physical experiments,we obtained that the initial blasting stress,displacement and overpressure of the liquid–solid coupling blast are much better than that of ordinary blasting.The technology has been used in the relative coal mine,and the application results show that the technique has effectively prevented the coal and gas outburst,which has a wide range of application.

Model-based trajectory tracking control for an electrohydraulic lifting system with valve compensation strategy

The natural frequency of the electrohydraulic system in mobile machinery is always very low,which brings difficulties to the controller design.To improve the tracking performance of the hydraulic system,mathematical modeling of the electrohydraulic lifting system and the rubber hose was accomplished according to an electrohydraulic lifting test rig built in the laboratory.Then,valve compensation strategy,including spool opening compensation (SOC) and dead zone compensation (DZC),was designed based on the flow-pressure characteristic of a closed-centered proportional valve.Comparative experiments on point-to-point trajectory tracking between a proportional controller with the proposed compensations and a traditional PI controller were conducted.Experiment results show that the maximal absolute values of the tracking error are reduced from 0.039 m to 0.019 m for the slow point-to-point motion trajectory and from 0.085 m to 0.054 m for the fast point-to-point motion trajectory with the proposed compensations.Moreover,tracking error of the proposed controller was analyzed and corresponding suggestions to reduce the tracking error were put forward.

POTENT HYPOTENSIVE EFFECTS OF ORPHANIN FQ IN CONSCIOUS STROKE-PRONE SPONTANEOUSLY HYPERTENSIVE RATS

Orphanin FQ（OFQ） or nociceptin is a novel neuropeptide consisting of 17 amino acids. This peptide has a primary structure reminiscent of that of opioid peptide but exhibits an opposite effect to make animals hyperreactive. The effect of this new peptide on cardiovascular function are not completely known. The present study was conducted to investigate the effect of intravenous bolus injection of orphanin FQ on mean arterial blood presure （MABP） in conscious stroke-prone spontaneously hypertensive rats (SHRsp). Adult male SHRsp and Wistar normotensive rats （250～300 g body weight, 2. 5～3 months old） were used in this study. The MABP was measured in the conscious state by a tail-cuff method. In SHRsp model, intravenous bolus injection of orphanin FQ or Tyr1-orphanin FQ （0. 5 mg/kg） induced a prolonged and marked reduc- tion in MABP. The maximum changes in MABP were -30. 2±4. 2 mmHg by orphanin FQ and -28. 2± 4. 7 mmHg by Tyr1-orphanin FQ at 10 min after administration,and this effect lasted over 30 min. The Phe1→Tyr substitution in orphanin FQ was found to retain almost fully hypotensive activity. Pretreatment of SHRsp with naloxone-HCI（60 μg/kg）, 5 min before the injection of orphanin FQ, did not block the hy- potensive effect of orphanin FQ. Therefore, opioid receptors could not account for the hypotensive effect of orphanin FQ in SHRsp. In Wistar rats, intravenous bolus injection of the same dose of orphanin FQ did not cause a change in MABP. These observations suggest that orphanin FQ is a novel hypotensive peptide and may have some role in the regulation of blood pressure in SHRsp, rather than in normotensive rats. The ex-act underlying mechanisms are waiting to be clarified.

Integrated Multi-channel High Accuracy Current Control LED Driver with Low Dropout Regulator

This research describes an integrated multi-channel high accuracy current control LED （light emitting diode） driver with low dropout regulator implemented in a 0.35μm TSMC 2P4M CMOS process. With the new trend of backlighting applications for mobile electronics and portable devices requiring a smaller size, lower cost, lesser noise and accurate current control LED driver, it came up with the idea of integrating more than one design features within a single chip. The analysis of using a capacitor-less low dropout regulator to power the constant current source has been explored, with the implementation of wide range battery voltage of 3 V to 5 V. Possible load current variations were introduced and verified to output a fixed voltage of 2.8 V. A regulated cascode current mirror structure forms the multi-channel configuration string of LED＇s; the design ensures a current matching of less than 1% error and achieves a high accuracy current control of less than 1% error, regardless of the LED＇s forward voltage variation. Moreover, for high end portable device with multimedia applications, dimming frequency can be set to 10 MHz. In addition, a switching output is a better approach for managing LED＇s contrast and brightness adjustment as well as maximizing power consumption, ensuring longer life for driving string of LEDs.

矿用重型风镐推进机构控制系统研究

文章介绍了矿用全气动重型风镐破煤机推进机构的工作原理和控制方式的设计,为全气动重型风镐破煤装置提供了不同于气腿式凿岩机节流型调压的一种降压型调压方案,设计了一种杠杆直动式压力控制装置,并对其调压性能进行了AMESim仿真分析,为实物样机的设计制造提供了参考。对样机进行了测试,以检验设计的合理性。

Modelling and Predictive Control of a Buck-Boost DC-DC Converter

A predictive current control algorithm for the Buck-Boost DC-DC converter is presented in this paper. The continuous time model of the system is properly introduced, then, by imposing a proper PWM modulation pattern, its discrete time model is achieved. This last one is successfully employed in determining the steady state locus of the Buck-Boost converter, both in CCM （continuous conduction mode） and DCM （discontinuous conduction mode）. A novel continuous time equivalent circuit of the converter is introduced too, with the aim of determining a ripple free representation of the state variables of the system, over both transient and steady state operation. Then, a predictive current control algorithm, suitable in both CCM and DCM, is developed and properly checked by means of computer simulations. The corresponding results have highlighted the effectiveness of the proposed modelling and of the predictive control algorithm, both in CCM and DCM.