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Chinese Physics Letters 2021年第9期38卷 38-42页

作者： Chuyi Huang Junpei Zhang Fan Ye Zecong Qin syed Mohd amir Zachary Norris Buck Ahmed Salman Wolfgang Kreuzpaintner Xin Qi Tianhao Wang Xin Tong Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China Spallation Neutron Source Science Center Dongguan 523803China

Polarized 3He neutron spin filters(NSFs)can be used as a vital tool for neutron polarization production and *** China Spallation Neutron Source(CSNS),as one of the major neutron facilities in China,has committed resources to the development of a polarized ^(3)He NSF program to support its growing polarized neutron research.A spin-exchange optical pumping(SEOP)-based polarized ^(3)He system and other necessary hardware for NSF transport has been recently *** performance of the system is benchmarked using an in-house developed cell named“Trident”.Neutron beam measurements yield a ^(3)He polarization of 77%with over 200 h of on-beam relaxation *** this newly developed SEOP system with the recently reported cell fabrication station,CSNS is now capable of the fully self-sustained production of ^(3)He NSFs that shall support its future neutron polarization research.

关键词： polarized system relaxation

Body Mass Index and Body Fat Percentage in Assessment of Obesity Prevalence in Saudi Adults

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Biomedical and Environmental Sciences 2013年第2期26卷 94-99页

作者： syed Shahid HABIB Department of Physiology College of Medicine&King Khalid University HospitalKing Saud University

Objective To assess the obesity prevalence in body mass index （BMI） and body fat percentage Saudi adults according to the international standards of （BF%）. Methods Five hundred and thirty healthy Saudi adults aged 18-72 years （mean 36.91＋15.22 years） were enrolled in this study. Their body composition was assessed by bioelectrical impendence analysis with a commercially available body composition analyzer. Standard BMI and BF% values were used to define obesity. Results The prevalence of underweight, normal underweight, overweight and obesity in Saudi adults according to the BMI criteria （〈18.5 kg/mz, 18.5-24.4 kg/m2, 25-29.9 kg/m2, 30 k＆/m2 and above, respectively） was 2.5%, 30.2%, 33.6%, and 33.8%, respectively, whereas the obesity prevalence was 60% （n=31g） in Saudi adults according to the BF% criteria （25% for males and 30% for females）, which was significantly higher than that according to BMI criteria. However, it was 50.6% （n=268） when the BMI cutoff point was 27.5 kg/m2, proposed by WHO for the Asian population. Kappa analysis showed that the obesity prevalence defined by BMI and BF% was higher in females than in males （k=0.530 vs k=0.418, P〈O.O001）. The sensitivity and specificity of BMI （30 kg/m2 and 27.5 kg/m2） were 54.1% and 96.7% and 76.4% and 88.2%, respectively, for obesity. A lower BMI cutoff point （26.60 kg/m2） was proposed in this study, which gave the maximum sensitivity （84.3%） and specificity （85.4%）, with a moderate kappa agreement （k=0.686）. Moreover, the obesity prevalence at this cutoff point （56.4%） was significantly higher than that recommended by WHO. Conclusion The specificity of BMI for obesity is high and its sensitivity is low in both sexes. Its sensitivity can be increased by changing BMI cutoff to a lower value. The choice of BF% reference is of great influence for the assessment of obesity prevalence according to the BMI.

关键词： Body composition Obesity Body mass index Body fat percentage Kappa analysis

COMPARISON OF TWO METHODS TO INCREASE TIP CLEARANCE AND ITS EFFECT ON PERFORMANCE OF TURBOCHARGER CENTRIFUGAL COMPRESSOR STAGE

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Chinese Journal of Mechanical Engineering 2007年第4期20卷 60-65页

作者： syed Noman Danish School of Mechanical and Vehicular Engineering Beijing Institute of TechnologyBeijing 100081China

Tip clearance between the blade tip and casing of a centrifugal compressor can be varied through two methods： by changing the blade height （MI） or by changing the casing diameter （M2）. Numerical simulations are carried out to compare these two methods and their effect on the stage and impeller performance. The impeller and diffuser are connected through rotor stator boundary using frozen rotor approach. Overall stage performance and the flow configuration have been investigated for nine tip clearance levels from no gap to 1 mm. Impeller and diffuser performances are also presented separately. It has been found that the overall and impeller performance are comparatively better for MI below tip clearance of 0.5 mm whereas M2 is found advantageous above 0.5 mm of tip clearance. Both MI and M2 show performance degradation with the increase in tip clearance. Two models have been proposed for the stage total pressure ratio and efficiency, which are found to be in agreement with experimental results. The impeller efficiency and the pressure ratio are found to be maximum at tip clearance of 0.1 mm for both the cases however minimum diffuser effectiveness is also observed at the same clearance level. Diffuser effectiveness is found to be maximum at zero gap for both cases. As it is practically impossible to have zero gap for unshrouded impellers so it is concluded that the optimum thickness is 0.5 mm onwards for MI and 0.5 mm for M2 in terms of diffuser effectiveness. Mass averaged flow parameters, entropy, blade loading diagram and relative pressure fields are presented, showing the loss production within the impeller passage with tip clearance.

关键词： Centrifugal impeller Diffuser Stage Tip clearance Numerical simulation Entropy

Use of Impella cardiac axial flow pump for cardiogenic shock(A newer alternative)-How good is the evidence?

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BIOCELL 2022年第5期46卷 1139-1150页

作者： RAFIQ AHMED BHAT syed manzoor ALI YOOSUF ALI ASHRAF MUHAMMAD HUSSENBOCUS AKANKSHA RATHI JAVAID AKHTER BHAT ABDUL ALEEM KHAN syed MAQBOOL RAJA SAQIB IQBAL MD MONOWARUL ISLAM YONGSHENG QU YOU ZHANG YUXIAO SUN WENTAO XIAO ABHISHEK TIBREWAL CHUANYU GAO Zhengzhou University People’s Hospital Department of CardiologyFuwai Central China Cardiovascular HospitalZhengzhouChina Department of Cardiology Super Speciality DivisionGovernment Medical CollegeSrinagarIndia Department of Rheumatology and Immunology Nanjing Drum Tower Hospital Clinical College of Nanjing Medical UniversityNanjingChina Department of Community Medicine Vedanta Institute of Medical SciencesPalgharIndia State Key Laboratory of Crop Genetics and Germplasm Enhancement Nanjing Agricultural UniversityNanjingChina Department of Orthopaedics Nanjing First HospitalNanjing Medical UniversityNanjingChina Department of Paediatrics Batra Hospital and Medical Research CentreNew DelhiIndia Zhengzhou University First Affiliated Hospital ZhengzhouChina Department of Community Medicine Institute of Biostatistics and EpidemiologyGurgaonIndia

The adverse outcomes of a ventricular heart failure(left,right or biventricular)caused by cardiogenic shock are aggravated by lung oedema and organ mal *** advances in medical sciences,revascularisation and mechanical hemodynamic support have proved ineffective in reducing the mortality rate in such patients.A thorough study of the data available about cardio-vascular diseases reveals that the application of conventional methods of treatment are least helpful to practically restore normal functions of heart when it experiences end-stage systolic ventricular ***,to overcome the challenges and find alternatives to address this issue,percutaneous ventricular support devices/machines were designed and successfully *** devices have revolutionized the treatment of ventricular heart failures and are now in use all over the *** this review paper a newer mechanical circulatory support(MCS)device,Impella,has been discussed and compared with a few other devices like Intra-aortic Balloon Pump(IABP),Extracorporeal Circulation(ECLS)and Veno-arterial Extracorporeal Membrane Oxygenation(VA-ECMO).This article studies the challenges being faced during the treatment of cardiogenic shock,and thoroughly discusses the use and effectiveness of Impella Cardiac Axial Pump in each *** can be said that mechanical circulatory support(MCS)device use during percutaneous coronary intervention(PCI)should be individualized based on multiple factors with a recommended use in patients with the greatest potential benefit and a relatively low risk of device-related *** current literature suggests that the outcomes of use of Impella and other mechanical circulatory support devices like IABP and VA-ECMO are *** there seem to be a few advantages of Impella over the others,sufficiently powered,multi-centric,randomised control trials are needed to establish its superiority.

关键词： Cardiogenic shock Hemodynamic support Impella Cardiac Axial Pump IABP VA-ECMO

Prediction of pressure gradient and hold-up in horizontal liquid-liquid pipe flow

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Petroleum Science 2023年第6期20卷 3766-3782页

作者： syed Amjad Ahmed Bibin John School of Mechanical Engineering Vellore Institute of TechnologyIndia Department of Mechanical Engineering C Abdul Hakeem College of Engineering&TechnologyIndia

This paper aims to propose correlations to predict pressure gradient,friction factor and fluid phase hold-up in liquid-liquid horizontal pipe *** develop the correlations,experiments are conducted using high viscous oils(202 and 630 mPa⋅s)in a steel pipe of length 11.25 m and length-to-diameter ratio of *** addition,the experimental data from the literature comprising wide range of flow and fluid properties is *** the analysis,the liquid-liquid pipe flow data is categorized into two as:stratified and *** existing friction factor correlations are modified to incorporate the effects of viscosity of the oil phase,interfacial curvature(contact/wetting angle-in lieu of material of the pipe)and fluid phase *** the two-fluid model of stratified flow,the wall stress and interfacial stress correlations are substituted with superficial velocities of fluids and superficial Reynolds numbers of fluid phases replacing fluid phase velocities and fluid Reynolds ***,for dispersed flow,an effective Reynolds number is described as the sum of superficial Reynolds number of oil and water *** the generally employed mean or mixture Reynolds number with the effective Reynolds number into the existing single-phase turbulent flow friction factor correlation,an effective friction factor for oil-water flow is *** the proposed correlations,the pressure gradient across the oil-water flow and hold-up volume fraction are predicted with significant reduction in error compared with that of conventionally employed *** average error and standard deviation values of−7.06%,20.72%and 0.31%,18.79%are found for stratified flow and dispersed flow respectively.

关键词： oil-water flow two-fluid model pressure gradient stratified flow dispersed flow

Robust H_∞ control for uncertain Markovian jump systems with mixed delays

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Chinese Physics B 2016年第7期25卷 108-113页

作者： R Saravanakumar M syed Ali Department of Mathematics Thiruvalluvar University

We scrutinize the problem of robust H∞control for a class of Markovian jump uncertain systems with interval timevarying and distributed delays. The Markovian jumping parameters are modeled as a continuous-time finite-state Markov chain. The main aim is to design a delay-dependent robust H∞control synthesis which ensures the mean-square asymptotic stability of the equilibrium point. By constructing a suitable Lyapunov–Krasovskii functional（LKF）, sufficient conditions for delay-dependent robust H∞control criteria are obtained in terms of linear matrix inequalities（LMIs）. The advantage of the proposed method is illustrated by numerical examples. The results are also compared with the existing results to show the less conservativeness.

关键词： linear matrix inequality Lyapunov method Markovian jumping parameters robust H∞ control

MECHANICALLY AND THERMALLY STABLE BLENDS OF POLY(STYRENE-BUTADIENE-STYRENE) WITH CONDUCTING POLY(THIOUREA-AZO-NAPHTHYL)

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Chinese Journal of Polymer Science 2013年第12期31卷 1623-1631页

作者： Ayesha Kausar syed Tajammul Hussain Nanosciences and Catalysis Division National Centre for PhysicsQuaid-i-Azam University Campus

A new aromatic azo-polymer, poly（thiourea-azo-naphthyl）（PTAN）, has been synthesized using 1-（5- thiocarbamoylaminonaphthyl）thiourea and diazonium salt solution of 2,6-diaminopyridine. PTAN was easily processable using polar solvents and had high molar mass 57 × 10^3 g/mol. Electrically conducting, mechanically and thermally stable rubbery blends of poly（styrene-butadiene-styrene）（SBS） triblock copolymer and PTAN were produced by solution blending technique. FESEM of SBS/PTAN blends revealed nano-scale dispersion of the conducting filler showing good adhesion between the matrix and PTAN. Remarkable effects of azo-content on the conductivity of SBS-based blends have been observed. Accordingly, PTAN loading from 10 to 60 wt% increased the conductivity from 1.24 to 1.66 S/cm. Relationship between PTAN loading and thermal stability of the materials was also investigated. With increasing the PTAN content, 10% gravimetric loss was increased from 484 to 500 ℃, while glass transition was enhanced from 119 to 126 ℃. Thermal and conducting data of the blend showed better results relative to pure elastomer but were lower than those of the conducting filler. Similarly, the tensile strength （57.35-62.33 MPa） of SBS/PTAN was improved relative to there of SBS. Fine balance of properties renders new materials fairly better than the existing elastomeric blends used in a number of applications.

关键词： Poly(thiourea-azo-naphthyl) SBS Electrical conduction Thermal stability Tensile strength.

Potassium ferro-cyanide trihydrate complex catalyzed one-pot synthesis of 2-phenylimidazo[4,5-f][1,10] phenanthroline

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Chinese Chemical Letters 2011年第7期22卷 793-796页

作者： syed Shahed Ali Organic Laboratory Department of Sir Sayyed CollegeDr.Babasaheb Ambedkarb Marathwada UniversityAurangabad 431001India

Various 2-phenylimidazo [4,5-f] [1,10] phenanthrolines were synthesized from potassium ferro-cyanide trihydrate （KFCT） complex catalyzed three component reaction of 1,10-phenanthroline-5,6-dione, aromatic aldehydes and ammonium acetate at room temperature in excellent isolated yield. This is a simple and straight forward, high yielding, not involving any hazardous or expensive catalyst method.

关键词： 2-Phenylimidazo [4,5-f] phenanthrolines Aromatic aldehyde K4[Fe(CN)6]·3H2O Ammonium acetate

STOCHASTIC STABILITY OF UNCERTAIN RECURRENT NEURAL NETWORKS WITH MARKOVIAN JUMPING PARAMETERS

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Acta Mathematica Scientia 2015年第5期35卷 1122-1136页

作者： M.syed ALI Department of Mathematics Thiruval luvar University

In this paper, global robust stability of uncertain stochastic recurrent neural networks with Markovian jumping parameters is considered. A novel Linear matrix inequal- ity（LMI） based stability criterion is obtained to guarantee the asymptotic stability of uncertain stochastic recurrent neural networks with Markovian jumping parameters. The results are derived by using the Lyapunov functional technique, Lipchitz condition and S-procuture. Finally, numerical examples are given to demonstrate the correctness of the theoretical results. Our results are also compared with results discussed in [31] and [34] to show the effectiveness and conservativeness.

关键词： Lyapunov functional linear matrix inequality Markovian jumping parameters recurrent neural networks

Steady-state security in distribution networks with large wind farms

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Journal of Modern Power Systems and Clean Energy 2014年第2期2卷 134-142页

作者： Dilan JAYAWEERA syed ISLAM Curtin University PerthWA 6102Australia

Aging network assets,forced and unforced outages,and the way the networks are operated in a deregulated market are of significant concerns to integrate large wind farms in a distribution *** many cases,the constrained network capacity is a potential barrier to the large-scale integration of wind *** paper probabilistically assesses the steady-state security in a distribution network in the presence of large wind *** approach incorporates active distribution network operating conditions,including intermittent power outputs,random outages,demand fluctuations,and dynamic interactions and exchanges,and then assesses the steady state security using Monte Carlo simulation.A case study is performed by integrating large wind farms into a distribution *** results suggest that intermittent outputs of large wind farms in a distribution network can impact the steady-state security ***,the level of impact of wind farms does not necessarily correlate with the installed capacity of them.

关键词： Monte Carlo simulation Network integration capacity Random outages Security of supply Wind power generation