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Numerical analysis of the hydraulic fracture communication modes in fracture-cavity reservoirs

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Petroleum Science 2022年第5期19卷 2227-2239页

作者： Jia-Wei kao Shi-Ming Wei Wen-Zhi Wang Yan Jin State Key Laboratory Petroleum Resources and Prospecting China University of PetroleumBeijing102249China Sinopec Research Institute of Petroleum Engineering Beijing102206China CNPC Engineering Technology R&D Company Limited Beijing102206China

The fracture-cavity carbonate reservoirs in the Tahe Oilfield in China are mainly exploited by *** need the hydraulic fractures to communicate with caves to create a flow ***,due to the existence of the fracture-cavity systems,the hydraulic fracture propagation morphology is complicated,while the propagation characteristics are not *** analyze the hydraulic fracture propagation in fracture-cavity carbonate formations,based on the discontinuous discrete fracture model,we developed a solid-seepage-freeflow coupled fracturing model for fracture-cavity formations,which can simulate the complex interaction behavior of fractures and *** on the simulation results,we found the interaction rule between hydraulic fractures and fracture-cavity systems:the stress concentration around caves is the main factor that determines the fracture propagation *** due to stress concentration is usually not conducive to communication,while natural fractures distributed around caves could break the rejection *** the hydraulic energy in the hydraulic fracture can make fracture propagate directly and reduce the influence of *** steering fracture formed by temporary plugging is beneficial to the communication of fracture-cavity systems in the non-principal stress *** to the simulation results of different fracture-cavity characteristics,we raised four optimization communication modes for fracture-cavity carbonate formation to provide references for fracturing optimization design and parameter optimization.

关键词： Fracture-cavity carbonate formation Hydraulic fracture propagation Numerical simulation Fracture-cave communication Discontinuous discrete fracture model

Decision making in right-sided diverticulitis

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World Journal of Gastroenterology 2003年第3期9卷 606-608页

作者： Li-Rung Shyung Shee-Chan Lin Shou-Chuan shih Chin-Roa kao Sun-Yen Chou Division of Gastroenterology Department of Internal MedicineMackay Memorial HospitalTaipeiTaiwanChina

AIM: To evaluate systematically our nine-year experience in treating right-sided diverticulitis of the colon, and to explore its clinical and radiological ***: The clinical and radiological data of 40 patients with colonic diverticulitis treated in Mackay Memorial Hospital,Taipei, from 1993 through 2002 were reviewed ***: The average age of the patients with right-sided diverticulitis was 53.1 years, which was 11.6 years younger than that of the patients with left-sided diverticulitis. The preoperative diagnosis of appendicitis was made in 8 of 13 right-sided diverticulitis patients. Nine (69 %) had right lower quadrant abdominal pain for more than 48 hours, and ten patients (77 %) presented with fever. CT findings suggesting acute right-sided diverticulitis including thickening of the intestinal wall and pericolonic inflammation were present in five ***: Right-sided diverticulitis is easily confused with acute appendicitis because it occurs at a somewhat younger age than that in left-sided diverticulitis. Barium enema and CT are helpful for the early diagnosis of rightsided diverticulitis. While clearly not required in the majority of patients with right lower quadrant abdominal pain, barium enema and CT may be helpful in making the decision with a clinical history or physical examinations atypical of acute appendicitis.

关键词：右结肠憩室炎放射影像学临床特点 CT表现诊断

Application of a screw conveyor with axial tilt blades on a shearer drum and investigation of conveying performance based on DEM

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Particuology 2022年第2期20卷 91-102页

作者： Liqing Sun Xiaodi Zhang Qingliang Zeng Kuidong Gao kao Jiang Jiawei Zhou College of Mechanical and Electronic Engineering Shandong University of Science and TechnologyQingdao 266590China Shandong Province Key Laboratory of Mine Mechanical Engineering Shandong University of Science and TechnologyQingdao 266590China School of Information Science and Engineering Shandong Normal UniversityJinan 250014China School of Mechanical Engineering North China University of Water Resources and Electric PowerZhengzhou 450045China

Screw conveyors are widely employed in industrial fields for conveying bulk *** shearer drum which uses the screw conveying principle is responsible for excavation and conveying coal particles onto the chain *** conveyor performance is affected by potential factors,such as the blade axial tilt angle and style,core shaft form and *** effect of blade axial tilt angle on the conveying performance was investigated with the help of *** the case of the screw conveyor,the mass flow rate,and particle axial velocity increased with increasing positive axial tilt angle,and declined with increasing negative axial tilt *** the case of the drum,the mass flow rate,particle axial velocity,and loading rate first increased and then decreased with increasing positive axial tilt angle,and decreased with increasing negative axial tilt *** results can be considered as a benchmark for screw conveyor and drum structural designs with axial tilt screw blades.

关键词： Screw conveyor Drum Axial tilt angle Conveying performance DEM

Costal cartilage graft in Asian rhinoplasty: surgical techniques

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Plastic and Aesthetic Research 2019年第4期6卷 1-10页

作者： Sarina Rajbhandari Chuan-Hsiang kao Department of Otolaryngology-Head and Neck Surgery Himal HospitalKathmandu 44600Nepal Department of Otolaryngology-Head and Neck Surgery Tri-Service General HospitalTaipei 11490Taiwan.

Asian rhinoplasty is a very common cosmetic *** Asians desire a higher nasal bridge,for which they undergo several procedures,including filler injections,implantations and insertion of *** encounter many patients who have had several procedures done on them *** this paper,we introduce the use of autologous grafts for Asian rhinoplasty(primary and secondary),and discuss the rib carving techniques and difficulties encountered during harvesting,carving and placements of grafts and how to overcome these problems and prevent complications.

关键词： Rhinoplasty costal cartilage Asians warping

Numerical and experimental studies of hydrodynamics of flapping foils

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Journal of Hydrodynamics 2018年第2期30卷 258-266页

作者： Kai Zhou Jun-kao Liu Wei-shan Chen College of Mechanical and Electronic Engineering Shandong Agricultural University Taian 271018 China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin 150001 China

The flapping foil based on bionics is a sort of simplified models which imitate the motion of wings or fins of fish or birds. In this paper, a universal kinematic model with three degrees of freedom is adopted and the motion parallel to the flow direction is considered. The force coefficients, the torque coefficient, and the flow field characteristics are extracted and analyzed. Then the propulsive efficiency is calculated. The influence of the motion parameters on the hydrodynamic performance of the bionic foil is studied. The results show that the motion parameters play important roles in the hydrodynamic performance of the flapping foil. To validate the reliability of the numerical method used in this paper, an experiment platform is designed and verification experiments are carried out. Through the comparison, it is found that the numerical results compare well with the experimental results, to show that the adopted numerical method is reliable. The results of this paper provide a theoretical reference for the design of underwater vehicles based on the flapping propulsion.

关键词： Biological fluid dynamics flapping foil hydrodynamic performance numerical simulation

Nitrogen fertilization has minimal influence on rhizosphere effects of smooth crabgrass (Digitaria ischaemum) and bermudagrass (Cynodon dactylon)

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Journal of Plant Ecology 2015年第4期8卷 390-400页

作者： Biao Zhu Kevin Panke-Buisse Jenny kao-Kniffin Earth Sciences Division Lawrence Berkeley National LaboratoryCyclotron RoadBerkeleyCA 94720USA School of Integrative Plant Science Cornell University134 Plant Sciences BuildingIthacaNY 14853USA

Aims Plants generally respond to nitrogen(N)fertilization with increased growth,but N addition can also suppress rhizosphere effects,which consequently alters soil *** quantified the influence of N addition on rhizosphere effects of two C4 grasses:smooth crabgrass(Digitaria ischaemum)and bermudagrass(Cynodon dactylon).Methods Plants were grown in nutrient-poor soil for 80 days with either 20 or 120μg NH4No3-N g dry soil−1.N mineralization rates,microbial biomass,extracellular enzyme activities and bacterial community structure were measured on both rhizosphere and bulk(unplanted)soils after plant *** Findings Fertilization showed nominal differences in net N mineralization,extracellular enzyme activity and microbial biomass between the rhizosphere and bulk soils,indicating minimal influence of N on rhizosphere ***,the presence of plant roots showed the strongest impact(up to 80%)on rates of net N mineralization and activities of three soil enzymes indicative of N release from organic *** component analysis of terminal restriction fragment length polymorphism(t-rFlP)also reflected these trends by highlighting the importance of plant roots in structuring the soil bacterial community,followed by plant species and N fertilization(to a minor extent).overall,the results indicate minor contributions of short-term N fertilization to changes in the magnitude of rhizos-phere effects for both grass species.

关键词： rhizosphere effect N fertilization belowground carbon allocation microbial biomass extracellular enzyme net N mineralization microbial community composition

A novel structural modeling and analysis of VLSI interconnect with an RLC tree network system using a BG/SEBD approach

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Science China(Information Sciences) 2011年第9期54卷 1968-1985页

作者： CHANG RueyFong kao WenShiow TSENG KuoHsiung HUANG shihYing Department of Electrical Engineering National Taipei University of Technology Department of Environmental Resources Management Transworld Institute of Technology

A practical and effective novel graphical structural modeling and analysis approach is *** approach is used for solving the state interactions modeling problem caused by the model approximations in VLSI interconnect for RLC tree network *** bond graph (BG) energy model with a simulink energy-based block diagram (SEBD) algorithm is *** dynamic behaviors of an example of VLSI interconnect with a 20th-order RLC tree are *** of sequent structuring and the delineation of dynamic interactions can be provided for users applying the BG/SEBD algorithms in the development of structural *** is shown that the new BG/SEBD structural modeling approach requires neither mathematical higher-order reduction nor physically based model ***,useful information can be extracted from the BG/SEBD representation of physical RLC tree network *** time-domain and frequency-domain simulation results are applied to analyze the dynamic response of energy-storing elements using BG/SEBD algorithm combined with Matlab/Simulink ***,a causal analysis of the system zeros plot from the shortest causal path method is proposed,to predict the dynamic response of energy-storing elements and the system performance for design and verification *** dynamic response outputs from different node points were revealed,and the obtained physical information is significant which suggests feasible directions for design (re-design) improvement toward better overall system performance.

关键词： higher-order RLC tree interconnect network (RLC-TIN) bond graph (BG) structural modeling time-domain and frequency-domain analysis causality analysis

A rotary ultrasonic motor using radial bending mode of ring with nested PZT excitation

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2012年第3期13卷 189-196页

作者： Ying-xiang LIU Jun-kao LIU Wei-shan CHEN Xiao-hui YANG State Key Laboratory of Robotics and System Harbin Institute of Technology Horbin 150001 China

This study presents and verifies a new idea for constructing a rotary traveling wave ultrasonic motor （USM） that uses the radial bending mode of a ring. In the new design, 20 trapezoid cross section slots are cut symmetrically in the outer surface of a thick duralumin alloy ring, where 20 PZT stacks are nested. In each slot, two wedging blocks are set between the PZT stack and the two sides of the slot respectively to apply preloading on the PZT ceramics. Two radial bending modes of the stator that have a phase difference of a quarter wavelength on space are generated by using the d33 operating mode of the PZT elements, and then a flexural traveling wave is formed by the superimposing of two standing waves whose amplitudes are equal and phases are different by 90~ temporally. Two conical rotors are pressed to each end of the ring type stator by a coiled spring. The finite element method （FEM） simulation is developed to validate the feasibility of the proposed motor. The maximal speed and torque of the prototype are tested to be 126 r/rain and 0.8 N＇m, respectively.

关键词： Rotary ultrasonic motor Radial bending mode Traveling wave Wedging block clamped structure

A unified intrinsic functional expansion theory for solitary waves

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Acta Mechanica Sinica 2005年第1期21卷 1-15页

作者： Theodore Yaotsu Wu John kao Jin E.Zhang California Institute of Technology Pasadena.CA 91125U.S.A.FellowInstitute of MechanicsChinese Academy of SciencesBeijing 100080China Warner Brothers GlendaleCA 91203.U.S.A. The university of Hong Kong.Pokfulam Road.Hong Kong SAR.China

A new theory is developed here for evaluating solitary waves on water, with results of high accuracy uniformly valid for waves of all heights, from the highest wave with a corner crest of 120 down to very low ones of diminishing height. Solutions are sought for the Euler model by employing a unified expansion of the logarithmic hodograph in terms of a set of intrinsic component functions analytically determined to represent all the intrinsic properties of the wave entity from the wave crest to its outskirts. The unknown coefficients in the expansion are determined by minimization of the mean-square error of the solution, with the minimization optimized so as to take as few terms as needed to attain results as high in accuracy as attainable. In this regard, Stokess formula, F2= tan , relating the wave speed (the Froude number F) and the logarithmic decrement of its wave field in the outskirt, is generalized to establish a new criterion requiring (for minimizing solution error) the functional expansion to contain a finite power series in M terms of Stokess basic term (singular in ), such that 2M is just somewhat beyond unity, i.e. 2M1. This fundamental criterion is fully validated by solutions for waves of various amplitude-to-water depth ratio =a/h, especially about 0.01, at which M=10 by the criterion. In this pursuit, the class of dwarf solitary waves, defined for waves with 0.01, is discovered as a group of problems more challenging than even the highest wave. For the highest wave, a new solution is determined here to give the maximum height hst=0.8331990, and speed Fhst=1.290890, accurate to the last significant figure, which seems to be a new record.

关键词： Solitary waves on water Unified intrinsic functional expansion theory Exact solutions High-accuracy computation of waves of arbitrary height Mass and energy transfer