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Asymmetric copolyimide membranes fabricated by nonsolvent-induced phase separation for He/CH_(4) and He/N_(2) separation

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Frontiers of Chemical Science and Engineering 2024年第4期18卷 97-106页

作者： Ying li lu Wang Junyan Xie Yong Dai Xuehong gu Xuerui Wang State Key laboratory of Materials-Oriented Chemical Engineering College of Chemical EngineeringNanjing Tech UniversityNanjing 211816China Quzhou Membrane Material Innovation Institute Quzhou 324000China

Membrane gas separation is considered an energy-saving technique to extract He from natural gas due to no phase change and room temperature ***,the membrane performance was strongly limited by the trade-off between permeance and ***,novel 4,4′-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)-2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane(APAF)-5-amino-2-(4-aminobenzene)benzimidazole(BIA)asymmetric membranes with a thickness of 300 nm were successfully prepared by the non-solvent induced phase separation *** membrane performance was modulated by regulating dope solution compositions(e.g.,tetrahydrofuran and polymer concentration).The ideal He/CH_(4) selectivity was 124 and the optimized He permeance reached 87 GPU,beyond the current upper ***/CH_(4) selectivity was 75 and He permeance was 73 GPU for the binary mixture feed containing 0.2 mol%*** membrane showed good resistance to CO_(2) and C_(2)H_(6),which are the typical impurities in natural *** 6FDA-APAF-BIA membranes have good stability(>160 h),which can provide great potential in He extraction from natural gas.

关键词： He separation membrane natural gas copolyimide

An improved deviation model for transonic stages in axial compressors

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Chinese Journal of Aeronautics 2024年第7期37卷 93-108页

作者： Xiaochen WANG Xuesong lI Xiaodong REN Chunwei gu Xiaobin QUE guoyu ZHOU Department of Energy and Power Engineering Tsinghua UniversityBeijing 100084China China United Gas Turbine Technology Co.ltd. Beijing 102209China

Deviation model is an important model for through-flow analysis in axial *** analysis in classical deviation models is developed under the assumption of onedimensional flow,which is controlled by the continuity *** consider three-dimensional characteristics in transonic flow,this study proposes an improved theoretical analysis method combining force analysis of the blade-to-blade flow with conventional analysis of the continuity *** of shock structures on transverse force,streamwise velocity and streamline curvature in the blade-to-blade flow are analyzed,and support the analytical modelling of density flow ratio between inlet and outlet ***,a novel deviation model for transonic stages in axial compressors is proposed in this *** empirical coefficients are corrected based on the experimental data of a linear cascade,and the prediction accuracy is validated with the experimental data of a three-stage transonic *** novel model provides accurate predictions for meridional flow fields at the design point and performance curves at design speed,and shows obvious improvements on classical models by Carter and C¸etin.

关键词： Axial compressor Transonic flow Deviation model Through-flow method Aerodynamic performance

Torque limit-based Inertial Control Method Based on Delayed Support for Primary Frequency Control of Wind Turbines

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Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 561-570页

作者： Wei gu Zaiyu Chen Qun li Minghui Yin Qiang li Yun Zou School of Automation Nanjing University of Science and TechnologyNanjing 210094China State Grid Jiangsu Electric Power Co. Ltd.Research InstituteNanjing 211103China

To avoid the secondary frequency dip caused by the steep drop of the electrical power of wind turbines(WTs)at the end of frequency support stage,the torque limit-based iner-tial control(TlIC)method sets the power reference as a linear function of rotor speed,rather than the step form for the step-wise inertial ***,the compensation effect on the frequency nadir(FN)caused by the load surge is weakened as the TlIC power is no longer in the step ***,the maximum point of the frequency response component(FRC)contributed by TlIC occurs earlier than the minimum point of FRC corresponding to the load surge,so that the FN cannot be adequately ***,this paper first investigates the relation between the peak and nadir times of FRCs stimulated by the TlIC and load *** this basis,with the compensation principle of matching the peak and nadir times of FRCs,the improved TlIC method based on delayed support is ***,the effectiveness of the proposed method is validated via the experiments on the test bench of wind-integrated power system.

关键词： Wind turbine frequency response component torque limit inertial control delayed support

Regulation effect of the grille spacing of a funnel-type grating water–sediment separation structure on the debris flow performance

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Journal of Mountain Science 2024年第7期21卷 2283-2304页

作者： lI Shuai gu Tianfeng WANG Jiading WANG Fei lI Pu State Key laboratory of Continental Dynamics/Department of Geology Northwest UniversityXi’an 710069China Chengdu Institute of Mountain Hazards and Environment Ministry of Water Resources&Chinese Academy of SciencesChengdu 610299China

The size of pores or the grille spacing of water–sediment separation structures directly affects their regulation effect on the debris flow performance.A suitable pore size or grille spacing can effectively improve the water–sediment separation ability of the *** new funnel-type grating water–sediment separation structure(FGWSS)combines vertical and horizontal structures and provides a satisfactory water–sediment separation ***,the regulation effect of the grille spacing of the structure on the debris flow performance has not been *** regulation effect of the structure grille spacing on the debris flow performance is studied through a flume test,and the optimal structure grille spacing is *** empirical equation of the relationship between the relative grille spacing of the structure and the sediment separation rate is ***,the influence of the water–sediment separation structure on the regulation effect of debris flows is examined from two aspects:external factors(properties of debris flows)and internal factors(structural factors).The experimental results show that the gradation characteristics of solid particles in debris flows constitute a key factor affecting the regulation effect of the structure on the debris flow *** optimum grille spacing of the FGWSS matches the particle size corresponding to the material distribution curves d85~d90 of the debris *** total separation rate of debris flow particles is related to the grille spacing of the structure and the content of coarse and fine particles in the debris flow.

关键词： Debris flow Water–sediment separation structure Grille spacing Performance regulation effect

Turbo-shaft engine adaptive neural network control based on nonlinear state space equation

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Chinese Journal of Aeronautics 2024年第4期37卷 493-507页

作者： Ziyu gu Qiuhong lI Shuwei PANG Wenxiang ZHOU Jichang WU Chenyang ZHANG Jiangsu Province Key laboratory of Aerospace Power System Nanjing University of Aeronautics and AstronauticsNanjing 210016China AECC Hunan Aviation Powerplant Research Institute Zhuzhou 412002China

Intelligent Adaptive Control(AC) has remarkable advantages in the control system design of aero-engine which has strong nonlinearity and uncertainty. Inspired by the Nonlinear Autoregressive Moving Average(NARMA)-l2 adaptive control, a novel Nonlinear State Space Equation(NSSE) based Adaptive neural network Control(NSSE-AC) method is proposed for the turbo-shaft engine control system design. The proposed NSSE model is derived from a special neural network with an extra layer, and the rotor speed of the gas turbine is taken as the main state variable which makes the NSSE model be able to capture the system dynamic better than the NARMA-l2 model. A hybrid Recursive least-Square and levenberg-Marquardt(RlS-lM) algorithm is advanced to perform the online learning of the neural network, which further enhances both the accuracy of the NSSE model and the performance of the adaptive controller. The feedback correction is also utilized in the NSSE-AC system to eliminate the steady-state tracking error. Simulation results show that, compared with the NARMA-l2 model, the NSSE model of the turboshaft engine is more accurate. The maximum modeling error is decreased from 5.92% to 0.97%when the lM algorithm is introduced to optimize the neural network parameters. The NSSE-AC method can not only achieve a better main control loop performance than the traditional controller but also limit all the constraint parameters efficiently with quick and accurate switching responses even if component degradation exists. Thus, the effectiveness of the NSSE-AC method is validated.

关键词： Adaptive control systems Turbo-shaft engine Neural network Nonlinear state space equation NARMA-l2

Assessment of International GNSS Service Global Ionosphere Map products over China region based on measurements from the Crustal Movement Observation Network of China

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Earth and Planetary Physics 2024年第2期8卷 400-407页

作者： Jin Hu HaiBing Ruan FuQing Huang ShengYang gu XianKang Dou Institute of Space Weather Nanjing University of Information Science and TechnologyNanjing 210044China State Key laboratory of Space Weather Chinese Academy of Sciences(CAS)Beijing 100190China School of Electronic Information Wuhan UniversityWuhan 430072China Wuxi Research Institute Nanjing University of Information Science and TechnologyWuxi Jiangsu 214000China CAS Key laboratory of Geospace Environment School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China

The global ionosphere maps(GIM)provided by the International GNSS Service(IGS)are extensively utilized for ionospheric morphology monitoring,scientific research,and practical *** the credibility of GIM products in data-sparse regions is of paramount *** this study,measurements from the Crustal Movement Observation Network of China(CMONOC)are leveraged to evaluate the suitability of IGS-GIM products over China region in *** indices of mean error(ME),root mean square error(RMSE),and normalized RMSE(NRMSE)are then utilized to quantify the accuracy of IGS-GIM *** revealed distinct local time and latitudinal dependencies in IGS-GIM errors,with substantially high errors at nighttime(NRMSE:39%)and above 40°latitude(NRMSE:49%).Seasonal differences also emerged,with larger equinoctial deviations(NRMSE:33.5%)compared with summer(20%).A preliminary analysis implied that the irregular assimilation of sparse IGS observations,compounded by China’s distinct geomagnetic topology,may manifest as error *** results suggest that modeling based solely on IGS-GIM observations engenders inadequate representations across China and that a thorough examination would proffer the necessary foundation for advancing regional total electron content(TEC)constructions.

关键词： International GNSS Service(IGS)Global Ionosphere Maps(GIM) Crustal Movement Observation Network of China(CMONOC) total electron content(TEC) data assessment

Added value of ratio of cross diameters of the appendix in ultrasound diagnosis of acute appendicitis

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World Journal of Gastrointestinal Surgery 2024年第1期16卷 21-28页

作者： Feng-Wa gu Si-Ze Wu Department of Ultrasound The First Affiliated Hospital of Hainan Medical UniversityHaikou 570102Hainan ProvinceChina

BACKGROUND The maximum outer diameter(MOD)of the appendix is an essential parameter for diagnosing acute appendicitis,but there is space for improvement in ultrasound(US)diagnostic *** To investigate whether combining the ratio of the cross diameters(RATIO)of the appendix with MOD of the appendix can enhance the diagnostic performance of acute *** A retrospective study was conducted,and medical records of 233 patients with acute appendicitis and 112 patients with a normal appendix were *** MOD and RATIO of the appendix were calculated and tested for their diagnostic performance of acute appendicitis,both individually and in *** The RATIO for a normal appendix was 1.32±0.16,while for acute appendicitis it was 1.09±*** cut-off value for RATIO was determined to be≤*** area under the receiver operating characteristic curve(AUC)for diagnosing acute appendicitis using RATIO≤1.18 and MOD>6 mm was 0.870 and 0.652,*** was a significant difference in AUC between RATIO≤1.18 and MOD>6 mm(P6 mm with MOD>6 mm alone,the combination showed increased specificity,positive predictive value(PPV),and ***,the sensitivity and negative predictive value *** Combining RATIO of the appendix≤1.18 and MOD>6 mm can significantly improve the specificity,PPV,and AUC in the US diagnosis of acute appendicitis.

关键词： Acute appendicitis Diameter Ratio Diagnosis Ultrasound

The impact of supply chain resilience on customer satisfaction and financial performance:A combination of contingency and configuration approaches

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Journal of Management Science and Engineering 2024年第1期9卷 38-52页

作者： Baofeng Huo Dan li Minhao gu College of Management and Economics Tianjin UniversityTianjin300072China

Supply chain resilience(SCR)refers to a supply chain's(SC's)ability to recover from disruptions timely and *** study uses a combination of contingency and configuration approaches to examine the direct and contingent relationships between SCR dimensions(i.e.,internal,supplier,and customer resilience)and *** analyzes survey data collected from 206 Chinese *** results show that the three SCR dimensions are positively related to customer satisfaction,whereas customer resilience has no direct contribution to financial *** resilience moderates the relationship between supplier resilience and performance(negative for customer satisfaction and positive for financial performance).A taxonomy for SCR was developed based on internal,supplier,and customer resilience,providing a holistic perspective for examining the performance discrepancies among four different SCR patterns:high externalleaning,high uniform,medium uniform,and low *** findings offer insights for managers in building SCR from the crisis-management process.

关键词： Supply chain resilience Risk management Taxonomy Performance China

Phase separation and transcriptional regulation in cancer development

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Journal of Biomedical Research 2024年第4期38卷 307-321页

作者： Yan gu Ke Wei Jun Wang Department of Thoracic Surgery Jiangsu Province Hospitalthe First Affiliated Hospital of Nanjing Medical UniversityNanjingJiangsu 210029China

liquid-liquid phase separation,a novel biochemical phenomenon,has been increasingly studied for its medical *** underlies the formation of membrane-less organelles and is involved in many cellular and biological *** transcriptional regulation,dynamic condensates are formed through interactions between transcriptional elements,such as transcription factors,coactivators,and *** is a disease characterized by uncontrolled cell proliferation,but the precise mechanisms underlying tumorigenesis often remain to be *** evidence has linked abnormal transcriptional condensates to several diseases,especially cancer,implying that phase separation plays an important role in *** formed by phase separation may have an effect on gene transcription in *** the present review,we focus on the correlation between phase separation and transcriptional regulation,as well as how this phenomenon contributes to cancer development.

关键词： phase separation transcription regulation cancer super-enhancer condensates