筋膜扩张器联合空心金属探子治疗男性尿道狭窄16例

目的：探讨筋膜扩张器联合空心金属探子治疗男性尿道狭窄有效性、安全性。方法：16例金属尿道探子扩张失败的尿道狭窄患者，在尿道镜或输尿管镜直视下斑马导丝通过狭窄段，沿斑马导丝依次用筋膜扩张器（F6～F18）及空心尿道探子（F20～F24）递增扩张尿道，留置F20气囊尿管2～4周。拔除尿管后，定期尿道扩张6～18月。结果：16例均扩张成功，无尿道穿孔、撕裂及假道形成。14例经定期尿道扩张治愈，2例因未定期扩张复发，再次内切开后定期扩张治疗后治愈。随访8～16月，无复发病例。结论：筋膜扩张器联合空心尿道探子行尿道扩张术治疗尿道狭窄安全、有效，具有损伤小、疗效好、并发症少等优点。

皮肤组织扩张术治疗瘢痕性秃发27例

瘢痕性秃发在烧伤整形科较常见,对于瘢痕性脱发病人,传统上都是应用切除瘢痕后,设计较为隐蔽部的局部头皮皮瓣转移,或应用显微外科技术游离头皮皮瓣等方法来治疗。但这都是属于拆东墙补西墙的移位措施,当脱发面积过大（超过整个头皮区30%）时,这些方法就难以奏效。

Fuzzy disturbance rejection predictive control of ultra-supercritical once-through boiler-turbine unit

In order to overcome the wide-range load tracking and unknown disturbance issues of an ultra-supercritical boiler- turbine unit, a fuzzy disturbance rejection predictive control approach is proposed using the techniques of fuzzy scheduling, model predictive control and extended state observer. Local state-space models are established on the basis of nonlinearity analysis and subspace identification. To eiJiance thedisturbance rejection capability of the controller, a extended state observer is employed to estimate unnown disturbances and model mismatches. The disturbance estimation ennaced local predictive controllers ae subsequently devised based on the local models, the performance of which is further strengthened by incorporating the fuzzy scheduling technique. The simulation results verify the merits of the proposed strategy in achieving satisfactory wide-range load tracking ad disturbance rejection performance.

Hyperbaric oxygen therapy for skin flap blood flow disorder: a case report

A female patient at the age of 17 received dilator implant on the right part of her face to prepare skin flap for her facial scar.The skin flap was in good conditions before scar cutting,but showed poor blood circulation after being transferred.Hyperbaric oxygen therapy was given at 0.2 MPa(2ATA) in double pure oxygen cabins for 90 min every day for 10 d.The skin flap showed in sound viability and sound blood circulation after the treatment.Hyperbaric oxygen therapy can be used to treat blood circulation disorder in transferred skin flap.

Metal stenting to resolve post-photodynamic therapy stricture in early esophageal cancer

Photodynamic therapy (PDT) is an established endoscopic technique for ablating Barrett's esophagus with high-grade dysplasia or early-stage intraepithelial neoplasia. The most common clinically significant adverse effect of PDT is esophageal stricture formation. The strictures are usually superficial and might be dilated effectively with standard endoscopic accessories, such as endoscope balloon or Savary dilators. However, multiple dilations might be required to achieve stricture resolution in some cases. We report the case of stricture that recurred after dilation with a bougie, which was completely relieved by a self-expandable metal stent.

Simulation on model predictive control for PMSM drive system based on double extended state observer

A novel double extended state observer(DESO)based on model predictive torque control(MPTC)strategy is developed for three-phase permanent magnet synchronous motor(PMSM)drive system without current sensor.In general,to achieve high-precision control,two-phase current sensors are necessary for successful implementation of MPTC.For this purpose,two ESOs are used to estimate q-axis current and stator resistance respectively,and then based on this,d-axis current is estimated.Moreover,to reduce torque and flux ripple and to improve the performance of the torque and speed,MPTC strategy is designed.The simulation results validate the feasibility and effectiveness of the proposed scheme.

Time-domain CFD computation and analysis of acoustic attenuation performance of water-filled silencers

The multi-dimensional time-domain computational fluid dynamics(CFD) approach is extended to calculate the acoustic attenuation performance of water-filled piping silencers. Transmission loss predictions from the time-domain CFD approach and the frequency-domain finite element method(FEM) agree well with each other for the dual expansion chamber silencer, straight-through and cross-flow perforated tube silencers without flow. Then, the time-domain CFD approach is used to investigate the effect of flow on the acoustic attenuation characteristics of perforated tube silencers. The numerical predictions demonstrate that the mean flow increases the transmission loss, especially at higher frequencies, and shifts the transmission loss curve to lower frequencies.

Differential geometric guidance command with finite time convergence using extended state observer

For improving the performance of differential geometric guidance command(DGGC), a new formation of this guidance law is proposed, which can guarantee the finite time convergence(FTC) of the line of sight(LOS) rate to zero or its neighborhood against maneuvering targets in three-dimensional(3D) space. The extended state observer(ESO) is employed to estimate the target acceleration, which makes the new DGGC more applicable to practical interception scenarios. Finally, the effectiveness of this newly proposed guidance command is demonstrated by the numerical simulation results.

Double ESOs-based field-oriented control for PMSM drive system with current sensorless

A novel double extended state observers(ESOs)-based field-oriented control(FOC)strategy is developed for three-phase permanent magnet synchronous motor(PMSM)drive systems without any phase current sensor.In principle,two current sensors are essential parts of the drive system for implementation of the feedback to achieve high accuracy control.For this purpose,the double ESOs are created to provide feedback stator currents instead of actual current sensors.The first one of the double ESOs is designed to estimate the benchmark value of q-axis stator current,which is a primary premise;While the second is designed to estimate real-time stator currents of d-axis and q-axis simultaneously.The resultant double ESOs can rapidly and accurately give estimation of the actual currents of a-axis,b-axis and c-axis,and the synthesized double ESOs-based FOC strategy for PMSM drive system without any current sensors has satisfactory control performance and strong robustness.Numerical experiments validate the feasibility and effectiveness of the proposed scheme.

Dynamic Positioning System Based on Active Disturbance Rejection Technology

A dynamically positioned vessel, by the International Maritime Organization （IMO） and the certifying class societies （DNV, ABS, LR, etc.）, is defined as a vessel that maintains its position and heading （fixed location or pre-determined track） exclu- sively by means of active thrusters. The development of control technology promotes the upgrading of dynamic positioning （DP） systems. Today there are two different DP systems solutions available on the market： DP system based on PID regulator and that based on model-based control. Both systems have limited disturbance rejection capability due to their design principle. In this paper, a new DP system solution is proposed based on Active Dis^n＇bance Rejection Control （ADRC） technology. This technology is com- posed of Tracking-Differentiator （TD）, Extended State Observer （ESO） and Nonlinear Feedback Combination. On one hand, both TD and ESO can act as filters and can be used in place of conventional filters; on the other hand, the total disturbance of the system can be estimated and compensated by ESO, which therefore enhances the system＇s disturbance rejection capability. This technology＇s advantages over other methods lie in two aspects： 1） This method itself can not only achieve control objectives but also filter noisy measurements without other specialized filters; 2） This method offers a new useful approach to suppress the ocean disturbance. The simulation results demonstrate the effectiveness of the proposed method.

Research on improved active disturbance rejection control of continuous rotary motor electro-hydraulic servo system

In order to meet the precision requirements and tracking performance of the continuous rotary motor electro-hydraulic servo system under unknown strong non-linear and uncertain strong disturbance factors,such as dynamic uncertainty and parameter perturbation,an improved active disturbance rejection control(ADRC)strategy was proposed.The state space model of the fifth order closed-loop system was established based on the principle of valve-controlled hydraulic motor.Then the three parts of ADRC were improved by parameter perturbation and external disturbance;the fast tracking differentiator was introduced into linear and non-linear combinations;the nonlinear state error feedback was proposed using synovial control;the extended state observer was determined by nonlinear compensation.In addition,the grey wolf algorithm was used to set the parameters of the three parts.The simulation and experimental results show that the improved ADRC can realize the system frequency 12 Hz when the tracking accuracy and response speed meet the requirements of double ten indexes,which lay foundation for the motor application.

Active disturbance rejection control FCS-MPC strategy based on ESO of PMSM system

In order to improve the control performance of three-phase permanent magnet synchronous motor(PMSM)system,an active disturbance rejection finite control set-mode predictive control(FCS-MPC)strategy based on improved extended state observer(ESO)is proposed in this paper.ESO is designed based on the arc-hyperbolic sine function to obtain estimations of rotating speed and back electromotive force(EMF)term of motor speed.Active disturbance rejection control(ADRC)is applied as speed controller.The proposed FCS-MPC strategy aims to reduce the electromagnetic torque ripple and the complexity and calculation of the algorithm.Compared with the FCS-MPC strategy based on PI controller,the constructed control strategy can guarantee the reliable and stable operation of PMSM system,and has good speed tracking,anti-interference ability and robustness.

Compound control for speed and tension multivariable coupling system of reversible cold strip mill

To weaken the nonlinear coupling influence among the variables in the speed and tension system of reversible cold strip mill, a compound control(CC) strategy based on invariance principle was proposed. Firstly, invariance principle was used to realize static decoupling between the speed and tension of reversible cold strip mill. Then, considering the influence caused by the time variation of steel coil radius and rotational inertia of the left and right coilers, as well as the uncertainties, a CC strategy that is composed of extended state observer(ESO) and global sliding mode control(GSMC) with backstepping adaptive was proposed,which further realized dynamic decoupling and coordination control for the speed and tension system. Theoretical analysis shows that the resulting closed-loop system is global bounded stable. Finally, the simulation was carried out on the speed and tension system of a 1422 mm reversible cold strip mill by using the actual data, and through the comparison of the other control strategies, validity of the proposed CC strategy was shown by the results.

A novel MPTC sensorless control strategy for ANFTSMC with ESO to control PMSM

Aiming at the problem that the traditional control strategy of permanent magnet synchronous motor(PMSM)for electric vehicles has low control performance,a novel adaptive non-singular fast terminal sliding mode control(ANFTSMC)model predictive torque control(MPTC)strategy is proposed.A new adaptive exponential approach rate is designed,and the traditional switching function sgn()is replaced by the hyperbolic tangent function tanh().A new ANFTSMC with extended state observer(ESO)is constructed as the speed regulator of the system,and ESO can observe disturbances.This improved method weakens chattering and improves the robustness of the system.To realize sensorless control of the speed control system,an ESO speed observer based on tanh(Fal)is constructed.Compared with the traditional ESO based on Fal function,the observation error is smaller,and the observation accuracy is higher.Finally,aiming at the model predictive torque control strategy used,a new objective function construction method is proposed,which avoids the design of weight coefficient,and the traditional voltage vector selection method is improved and optimized,which reduces the calculation amount of the algorithm.

Tension Active Disturbance Rejection Control of Automatic Yarn Splicing Robots for Ring Spinning

Automatic splicing of interrupted yarns in ring spinning has always been a problem in the industry.Factors such as low yarn strengths and environmental influence on yarn tensions make it difficult to control the yarn tension during the robotic splicing process.The purpose of this research is to design active disturbance rejection control(ADRC)for a third-order nonlinear tension system subject to external disturbances.Firstly,a third-order extended state observer(ESO)is designed to achieve the suppression and the compensation of the internal modeling error and the external disturbances of the system.Secondly,the adaptive gain error feedback control and the filtering process are designed to reduce the influence of sensor noise on the disturbance observation.Finally,the tension control during the splicing process is simulated and experimented,and the experiments show that the method has good robustness in the tension tracking task under a dynamic environment,which verifies the effectiveness of the method.

Treatment of osteoporotic compression fracture of thoracic/lumbar vertebrae by kyphoplasty with SKY bone expander system

Objective： To investigate prospectively the effectiveness ofkyphoplasty with SKY bone expander system in treatment of compression fracture of thoracic/ lumbar vertebrae and correction of the deformity. Methods： Twenty-five patients with thoracic/lumbar vertebral osteoporotic compression fracture were admitted to our hospital between March 2007 and March 2008, and treated by kyphoplasty with SKY bone expander system. Patient＇s pain status was rated with Visual Analogue Scale （VAS） score system 1 day before and 1 hour, 48 hours, 6 months, 12 months after surgery. In addition, Rolland-Mor- ris and Oswestry disability questionnaires （RDQ and ODI） were used for survey 1 day before and 1, 6, 12 months after surgery. Pre- and post-operative vertebral heights and Cobb＇s angles were measured based on the X-ray films and statistically analyzed. Results： There were 27 fractured vertebrae in these 25 patients. After SKY kyphoplasty, the Cobb＇s angles （9.8°±9.76°） were significantly reduced compared with preoperative angles （17.18°±9.35°, P〈0.05）, and the average improve- ment rate was 39%. Patients＇ pain VAS scores were also greatly improved after operation （P〈0.05）. Moreover, postoperative RDQ and ODI scores were significantly smaller than preoperative values （P〈0.05）. Conclusions： Kyphoplasty with SKY bone expander system provides an effective method for treating thoracic/ lumbar vertebral osteoporotic compression fracture, with the advantages of small surgical wound and short duration. It can effectively recover the anterior and medial heights of fractured vertebrae （33% and 50%, respectively）, reduce the Cobb＇s angle, quickly alleviate pain and improve patients＇ quality of life in a relatively short time period.

The Effect of Spherical Surface on Noise Suppression of a Supersonic Jet

Experiments were carried out to eliminate the screech tone generated from a supersonic jet. Compressed air was passed through a circular convergent nozzle preceded by a straight tube of same diameter. In order to reduce the jet screech a spherical reflector was used and placed at the nozzle exit. The placement of the spherical reflector at the nozzle exit controlled the location of the image source as well as minimized the sound pressure at the nozzle exit. The weak sound pressure did not excite the unstable disturbance at the exit. Thus the loop of the feedback mechanism could not be accomplished and the jet screech was eliminated. The technique of screech reduction with a flat plate was also examined and compared with the present method. A good and effective performance in canceling the screech component by the new method was found by the investigation. Experimental results indicate that the new system suppresses not only the screech tones but also the broadband noise components and reduces the overall noise of the jet flow. The spherical reflector was found very effective in reducing overall sound pressure level in the upstream region of the nozzle compared to a flat plate. The proposed spherical reflector can, accordingly, protect the upstream noise propagation.