Vertical human-induced vibration of pedestrian bridge

The double degrees-of-freedom（DOFs）parallel model is adopted to analyze static vertical human-induced vibration with the finite element analysis（FEA）method.In the first-order symmetric vibration mode,the periods of the spring-mass model gradually decrease with the increase in K1 and K2,but they are always greater than the period of the add-on mass model.Meanwhile,the periods of the spring-mass model decrease with the decrease in m1 and m2,but they are always greater than the period of the hollow bridge model.Since the human＇s two degrees-of-freedom vibrate in the same direction as that of the bridge mid-span,the existence of human＇s rigidity leads to the reduction in the rigidity of the spring-mass model.In the second-order symmetric vibration mode,the changes of rigidity K2 and mass m2 result in the disappearance or occurrence of some vibration modes.It can be concluded that compared with the spring-mass model,the results of the add-on mass model lean to lack of safety to the structure;besides,the DOF with a smaller ratio of mass to rigidity plays the chief role in the vibration of the structure.

Retrospect and Prospect of Excitation Systems of Large Size Turbogenerators

This paper briefs the developmental course, manufacturing and applications, as well as future prospect of excitation systems of large size turbogenerators in China, emphatically expounds the advantages of seif-excitation systems with potential source reetifiers and matters needing to be noted during dissemination and application of them.

Current Share Control IC Design for Paralleled DC/DC Converters

To keep even current distribution among DC/DC converters in a paralleled power system,an automatic master-slave control （AMSC） current sharing scheme is presented,which was implemented by a current share control IC. A current feedback loop for output voltage adjustment is proposed for low signal distortion. Moreover,a special startup control logic is designed to improve startup timing and to speed up the initial current sharing. It was completed in 1.5μm bipolar-CMOS-DMOS （BCD） technology with an area of 3.6mm^2 . Using it,a paralleled power system of two DC/DC converters capable of outputting 12V/3A was built. Experimental results show that the current sharing error at full load is kept within 1%.

Kinematics and dynamics analysis of a three-degree-of-freedom parallel manipulator

Kinematics and dynamics analyses were performed for a spatial 3-revolute joint-revolute joint-clylindric pair(3-RRC) parallel manipulator.This 3-RRC parallel manipulator is composed of a moving platform,a base platform,and three revolute joint-revolute joint-column pair chains which connect the moving platform and the base platform.Firstly,kinematics analysis for 3-RRC parallel manipulator was conducted.Next,on the basis of Lagrange formula,a simply-structured dynamic model of 3-RRC parallel manipulator was derived.Finally,through a calculation example,the variation of motorial parameters of this 3-RRC parallel manipulator,equivalent moment of inertia,driving force/torque and energy consumption was discussed.The research findings have important significance for research and engineering projects such as analyzing dynamic features,mechanism optimization design and control of 3-RRC parallel manipulator.

Synchronous tracking control of 6-DOF hydraulic parallel manipulator using cascade control method

The synchronous tracking control problem of a hydraulic parallel manipulator with six degrees of freedom (DOF) is complicated since the inclusion of hydraulic elements increases the order of the system.To solve this problem,cascade control method with an inner/outer-loop control structure is used,which masks the hydraulic dynamics with the inner-loop so that the designed controller takes into account of both the mechanical dynamics and the hydraulic dynamics of the manipulator.Furthermore,a cross-coupling control approach is introduced to the synchronous tracking control of the manipulator.The position synchronization error is developed by considering motion synchronization between each actuator joint and its adjacent ones based on the synchronous goal.Then,with the feedback of both position error and synchronization error,the tracking is proven to guarantee that both the position errors and synchronization errors asymptotically converge to zero.Moreover,the effectiveness of the proposed approach is verified by the experimental results performed with a 6-DOF hydraulic parallel manipulator.

Diagnosis and management of microscopic colitis

Microscopic colitis, comprising collagenous and lymphocytic colitis, is characterized clinically by chronic watery diarrhea, and a macroscopically normal colonic mucosa where diagnostic histopathological features are seen on microscoplc incidence of each disorder examination. The annual is 4-6/100000 inhabitants, with a peak incidence in 60-70-year-old individuals and a noticeable female predominance for collagenous colitis. The etiology is unknown. Chronic diarrhea, abdominal pain, weight loss, fatigue and fecal incontinence are common symptoms, which impair the health-related quality of life of the patient. There is an association with other autoimmune disorders such as celiac disease, diabetes mellitus, thyroid disorders and arthritis. Budesonide is the best-documented shortterm treatment, but the optimal long-term strategy needs further study. The long-term prognosis is good and the risk of complications including colonic cancer is low.

Role of Parallel Tempering Monte Carlo Simulation in 2D Ising Spin Glass System with Distance Dependent Interaction

Spin glass system is a complex disordered system with a number of local minima separated by entropic barriers. Therefore, parallel tempering Monte Carlo simulation was used in order to get fast thermalisation （to minimize the relaxation time）. Distance dependent interaction coupling in 2D is studied in order to show how a spin glass phase transition occurs when couplings between far away spins are permitted by considering Edwards-Anderson Ising spin glass model. The interaction coupling is a quenched random variable whose probability of being non-zero decays with distance between two spin sites rij = ｜i-j｜mod（L/2）.The interaction coupling is random and its probability distribution is decaying with the distance between the spins （p（Jij） αrij^-ρ）. The model is studied by changing p among three different regimes （p 〉 2D, 4/3 D〈 p 〈 2D, p 〈 4/3D）. A phase transition temperature for p = 2, 3, 4 is obtained.

Autoimmune pancreatitis complicated by gastric varices:A report of 3 cases

We present three cases of autoimmune pancreatitis(AIP) complicated by gastric varices.Case 1:A 57-yearold man was diagnosed with AIP complicated by gastric varices and splenic vein obstruction.Splenomegaly was not detected at the time of the diagnosis.The AIP improved using steroid therapy,the splenic vein was reperfused,and the gastric varices disappeared;case 2:A 55-year-old man was diagnosed with AIP complicated by gastric varices,splenic vein obstruction,and splenomegaly.Although the AIP improved using steroid therapy,the gastric varices and splenic vein obstruction did not resolve;case 3:A 68-year-old man was diagnosed with AIP complicated by gastric varices,splenic vein obstruction,and splenomegaly.The gastric varices,splenic vein obstruction,and AIP did not improve using steroid therapy.These three cases suggest that gastric varices or splenic vein obstruction without splenomegaly may be an indication for steroid therapy in patients with AIP because the complications will likely become irreversible over time.

Natural orifice transluminal endoscopic surgeryvs laparoscopic ovariectomy:Complications and inflammatory response

AIM:To compare natural orifice transluminal endoscopic surgery (NOTES) vs standard laparoscopic ovariectomy in mini pigs with respect to technical aspects,complications and parameters of systemic inflammatory response.METHODS:This was a randomized,experimental,survival study.Ten female mini pigs underwent NOTES transgastric ovariectomy (NOTES group) and ten female mini pigs underwent laparoscopic ovariectomy (LAP group).A "percutaneous endoscopic gastrostomy" approach with guidewire and sphincterotome was used for gastrotomy creation.The ovary was resected using standard biopsy forceps and a snare.The access site was closed using a "KING" closure with a single endoloop and several clips.In the laparoscopic group,a three-port laparoscopy and an ovariectomy were performed with the use of standard laparoscopic devices.C-reactive protein (CRP),white blood count and interleukin (IL)-6 plasma levels were used as indicators of systemic inflammatory response.All animals were euthanized 28 d after surgery.RESULTS:All animals survived without complications.The mean procedure time was 41.3 min ± 17.6 min (NOTES group) and 25.7 min ± 5.25 min (LAP group,P < 0.02).Postmortem examinations demonstrated that 50% and 70% of animals were free of any complications in the NOTES and LAP groups,respectively.The remaining animals developed minor complications (adhesions) in a comparable frequency between the two groups.In the NOTES group,one animal developed a small intramural gastric abscess close to the gastrotomy site.A minor serous exudate that was present in 50% and 40% of the animals in the NOTES and laparoscopy groups,respectively,was not considered a complication.In both groups CRP levels increased significantly on the 2nd and 7th postoperative days (POD) and returned to normal after 28 d.On POD 2,an increase of CRP level was significantly higher in the NOTES group compared to the LAP group.Values of IL-6 did not differ from baseline values in either of the groups postoperatively.Interestingly,the platelet count decreased significantly on POD 2,but returned close to baseline values on POD 7 and PODs 28-30.CONCLUSION:Both NOTES and laparoscopic ovariectomies had a similar frequency of minor complications.However,the NOTES technique produced an increased systemic inflammatory response on POD 2.

Singularity-free path planning for parallel manipulator

Given a start pose and a goal pose, a large number of singularity-free poses are created randomly in the 6 dimensional task space, a short line segment is used to create a feasible path between two singularity-free poses. A well connected roadmap can be obtained and stored in the 6 dimension task space for a specific 6 DOF parallel manipulator in this way and a singularity-free path is queried to connect the start pose and the goal pose. So the singularity-free path planning between any two given poses for this parallel manipulator can be performed very efficiently. This singularity-free path planning method can be used with any type of parallel manipulator only if the matrix used can be given to define singularities.

On the Ground State of Spin Systems with Orbital Degeneracy

In order to understand the properties of the spin system with orbital degeneracy, we first study the ground state of the SU(4) spin-orbital model on a square lattice. The mean-field results suggest that for a small Hund's interaction, the flavor liquid state is stable against the solid state, but with sufficient deviation from the SU(4) limit the long-range order may be attained in 2D system. Furthermore, we employ a variational approach to calculate the phase diagram of the ground state and the temperature-dependent susceptibility by taking into account the Hund's interaction and the anisotropy in orbital wavefunctions. Finally, the implications for the experimental observations on the material, , are discussed.

Diagnosis and management of late hepatic allograft dysfunction

Late hepatic allograft dysfunction (LHAD) is common after liver transplantation (LT) and can cause graft failure,retransplantation,or even death.A variety of etiologies including rejection,vascular complications,bile duct complications,recurrent diseases,infections,de novo diseases,neoplasms and drug toxicity can result in LHAD.The recurrent diseases have the potential to become the most serious problems facing LT in the future.It is difficult to differentiate late acute rejection from recurrent viral or autoimmune hepatitis.Accurate diagnosis of the cause of LHAD has therapeutic importance.

Research on Optimizing Numerical Calculation of Posture Equations based on Six DOF Stewart Platform

The paper study position positive solution method based on 6-TPS parallel mechanism, and establish general kinematics model of 6-TPS parallel mechanism, gives the numerical method of positive solution based on a kind of position, deduced the forward position solution iteration format, and use MATLAB for the 6-TPS parallel mechanism kinematics to simulation, results show that solving program has stability, fast. effective.

Efficacy and safety of limited endoscopic sphincterotomy before self-expandable metal stent insertion for malignant biliary obstruction

To evaluate the safety and efficacy of limited endoscopic sphincterotomy (ES) before placement of self-expandable metal stent (SEMS).METHODSThis was a retrospective analysis of 244 consecutive patients with unresectable malignant biliary obstruction, who underwent placement of SEMSs following limited ES from December 2008 to February 2015. The diagnosis of malignant biliary obstruction and assessment of patient eligibility for the study was established by a combination of clinical findings, laboratory investigations, imaging and pathological results. All patients were monitored in the hospital for at least 24 h following endoscopic retrograde cholangio pancreatography (ERCP). The incidence of immediate or early post-ERCP complications such as post-ERCP pancreatitis (PEP) and bleeding related to limited ES were considered as primary outcomes. Also, characteristics and complications according to the cancer type were classified.RESULTSAmong the 244 patients included, the underlying diagnosis was cholangiocarcinoma in 118 patients, pancreatic cancer in 79, and non-pancreatic or non-biliary malignancies in the remaining 47 patients. Early post-ERCP complications occurred in 9 patients (3.7%), with PEP in 7 patients (2.9%; mild, 6; moderate, 1) and mild bleeding in 2 patients (0.8%). There was no significant association between the incidence of post-ERCP complications and the type of malignancy (cholangiocarcinoma vs pancreatic cancer vs others, P = 0.696) or the type of SEMS used (uncovered vs covered, P = 1.000). Patients who had more than one SEMS placed at the first instance were at a significantly higher risk of post-ERCP complications (one SEMS vs two SEMS, P = 0.031). No other factors were predictive of post-ERCP complications.CONCLUSIONLimited ES is feasible and safe, and effectively facilitates the placement of SEMS, without any significant risk of PEP or severe bleeding.

Structural Synthesis, Dynamic Modeling and Analysis of a 3-DOF Asymmetric Parallel Mechanism

Most research papers about parallel kinematic chainmechanisms investigate symmetric robot manipulators, in which all the limbs connecting the end-effector to the fixed based are composed by the same sequence of links and joints. Contrarily, in some manipulation tasks the velocity and stiffness requirements are anisotropic. In such cases, the asymmetric parallel kinematic chain mechanisms may offer advantages. This work objective is to present the synthesis, dynamic modeling and analysis of a 3-dof asymmetric parallel chain mechanism, conceived as a robot manipulator for pick-and-place operations. Firs＇t, a structural synthesis, resulting in a three translations end-effector, and a kinematic modeling are carried out. Then, the inverse dynamic modeling is developed by employing the virtual work principle. Based on the model equations and on the saturation of the mechanism actuators, a maximum acceleration analysis is performed and shows that although the mechanism has a parallel architecture its actuators influences on the 3-dof are quite decoupled.

基于无线传感器网络定位技术的图书馆智能管理创新

"互联网+"时代,信息技术的发展对图书馆的智能化管理工作提出了更高的要求。文章概述了无线传感器网络与定位技术,重点讨论了如何将WSN定位技术运用到图书智能管理,通过定位技术与大数据、云计算等信息技术的结合,推动图书馆智能系统建设和智能化发展。

Type synthesis of the rotational decoupled parallel mechanism based on screw theory

With the gradual deepening of study on the parallel mechanism,the difficulty brought by the existence of coupling to the theoretical analysis and practical application of parallel mechanisms is becoming increasingly apparent.The research on the decoupled parallel mechanism is currently one of the hot fields.Though most of the rotational parallel mechanisms,which has been widely used in spatial orientation fields,are not decoupled.It is comparative difficult for the synthesis of fully decoupled rotational parallel mechanisms,and the number of the existing parallel mechanisms which can realize rotational decoupling is limited.In addition,most of the existing rotational decoupled parallel mechanism are obtained depending on the experience of the researcher,and don't possess the general theoretical significance.Based on the screw theory,this paper presents the rotational conditions of the parallel mechanism through the analysis of the relationship between the degree of freedom of the parallel mechanism and its limbs.The synthesis rule of the limbs for decoupled rotational parallel mechanism is established according to the twist screw system of the limbs,which assures the decoupling of the rotations in each limb.The selection principle of the input pairs for the rotation driven limbs is proposed,then the type synthesis method for rotational decoupled parallel mechanisms is formed.With this type synthesis method,synthesis of the rotational decoupled parallel mechanisms is performed,which can provide a reference for the development of the novel type parallel mechanisms with independent intellectual property rights.

Implementation of the moving particle semi-implicit method on GPU

The Moving Particle Semi-implicit (MPS) method performs well in simulating violent free surface flow and hence becomes popular in the area of fluid flow simulation. However, the implementations of searching neighbouring particles and solving the large sparse matrix equations (Poisson-type equation) are very time-consuming. In order to utilize the tremendous power of parallel computation of Graphics Processing Units (GPU), this study has developed a GPU-based MPS model employing the Compute Unified Device Architecture (CUDA) on NVIDIA GTX 280. The efficient neighbourhood particle searching is done through an indirect method and the Poisson-type pressure equation is solved by the Bi-Conjugate Gradient (BiCG) method. Four different optimization levels for the present general parallel GPU-based MPS model are demonstrated. In addition, the elaborate optimization of GPU code is also discussed. A benchmark problem of dam-breaking flow is simulated using both codes of the present GPU-based MPS and the original CPU-based MPS. The comparisons between them show that the GPU-based MPS model outperforms 26 times the traditional CPU model.

Hochschild cohomology of Beilinson algebra of exterior algebra

Let An be the Beilinson algebra of exterior algebra of an n-dimensional vector space, which is derived equivalent to the endomorphism algebra Endox （T） of a tilting complex T = II^ni=0^Ox （i） of coherent COx-modules over a projective scheme X = P^nk. In this paper we first construct a minimal projective bimodule resolution of An, and then apply it to calculate k-dimensions of the Hochsehild cohomology groups of An in terms of parallel paths. Finally, we give an explicit description of the cup product and obtain a Gabriel presentation of Hochschild cohomology ring of An. As a consequence, we provide a class of algebras of finite global dimension whose Hochschild cohomology rings have non-trivial multiplicative structures.

Parallel processing architecture of H.264 adaptive deblocking filters

In H.264,computational complexity and memory access of deblocking filters are variable,dependent on video contents.This paper proposes a VLSI architecture of deblocking filters with adaptive dynamic power,which avoids redundant computations and memory accesses by precluding the blocks that can be skipped.The vertical and horizontal edges are simulta-neously processed in an advanced scan order to speed up the decoder.As a result,dynamic power of the proposed architecture can be reduced adaptively(up to about 89%) for different videos,and the off-chip memory access is improved when compared to previous designs.Moreover,the processing capability of the proposed architecture is in particular appropriate for real-time deblocking of high-definition television(HDTV,1920×1080 pixels/frame,60 frames/s video signals) video operation at 62 MHz.Using the proposed architecture,power can be reduced by up to about 89% and processing time by from 25% to 81% compared with previous designs.