80,500 research outputs found
Lu Yu and Tu Fu
No full textLu Yu 陸游 (1125-1209), the famous patriot poet of the Southern Sung, admired Tu Fu above all the poets of the past, and the deep influence which Tu Fu exercised on him may be seen throughout his work. In spite of this fact, however, there are many differences which mark the lives and works of the two men. As a first step towards a comparative study of the two poets, the author has attempted to discover how Lu Yu evaluated his predecessor, using evidence found in Lu Yu's poems themselves. By Lu Yu's time, Tu Fu was already widely recognized as the greatest Chinese poet. It had become a popular pastime to try to identify individual poems of Tu Fu on the basis of isolated phrases or couplets, or to compose poems made up of clever imitations of various couplets of Tu Fu. But Lu Yu, unlike most of his contemporaries, was less attracted by Tu Fu's poetic technique than by his poetic spirit, and regarded the latter as the most valuable lesson to be learned. He insisted that it was Tu Fu the man rather than Tu Fu the poet, Tu Fu the patriot rather than Tu Fu the artist, who deserved to be most highly admired. This was the foundation upon which Lu Yu's evaluation of Tu Fu rested, and the premise upon which he approached his work
Optimization of a Composite Wing Subject to Multi Constraints
No full textIn this thesis, an investigation has been carried out into a minimum weight optimization analysis of a composite wing with multi design constraints under both static and dynamic loadings. The study includes the influence of a morphing leading edge on the wing stiffness and gust load reduction by employing a passive gust alleviation device at the wing tip.
The design process started from a generic study of optimal structure against buckling for three typical types of reinforced skin panel structures including stiffener panel, sandwich and grid panel. The optimal design in terms of buckling performance and structural efficiency were compared. The study then focused on the optimal design of stiffened skin panels for a particular wing. Parametric studies on optimal design for isotropic stiffened panels were carried out in which practical design constraints were introduced. The optimal design method was further extended to composite stiffened skin panels. Optimal designs were obtained within a compression distributed load range from 500 N/mm to 5250 N/mm and a symmetric balanced layup with 0˚, 90˚, and ±45˚ plies. Based on the study, the modelling and optimal design method for composite stiffened panels was applied to a composite wing box for its upper surface panel design. The initial composite wing box was designed to achieve a minimum weight. Gradient based optimization method was applied in the analysis with practical design constraints. The results indicate that the effect of leading edge morphing on the overall wing structural stiffness is negligible. It has been shown that the weight of the upper surface of the wing box structure can be reduced by 19.8% from its initial design.
Optimal design of a passive gust alleviation device (PGAD) mounted at the wing tip was then investigated. Based on the dynamic analysis of the 3D wing FE model in different flight and payload cases, a method and program was developed to create a dynamically equivalent beam model. Gust response of the optimized wing model was computed for a wide range of frequencies in accordance with the CS-25. Next, a parametric study of the key design variables of the PGAD was carried out to determine the optimal design parameters for minimum gust loading. The results have shown that the gust response can be reduced by 15% by using a 1m long PGAD for a conventional aircraft wing and yet reduce 50% tip displacement with 37.2% bending moment at wing root for a flying wing concept aircraft wing with 1.6m long PGAD mounted at the wing tip.
The results of the investigation contribute to knowledge in the following aspects. It provides an evaluation of the structural efficiency of three typical types of stiffened panels against buckling prevention. The research also provided an optimal design method for composite stringer stiffened panels by combining theoretical and practical design constraints. It made possible for the first-time a numerical evaluation of the novel PGAD as applied to a large aircraft
Optimal design of a composite wing structure for a flying-wing aircraft subject to multi-constraint
No full textThis thesis presents a research project and results of design and optimization of a composite wing structure for a large aircraft in flying wing configuration. The design process started from conceptual design and preliminary design, which includes initial sizing and stressing followed by numerical modelling and analysis of the wing structure. The research was then focused on the minimum weight optimization of the /composite wing structure /subject to multiple design /constraints. The modelling, analysis and optimization process has been performed by using the NASTRAN code. The methodology and technique not only make the modelling in high accuracy, but also keep the whole process within one commercial package for practical application.
The example aircraft, called FW-11, is a 250-seat commercial airliner of flying wing configuration designed through our MSc students Group Design Project (GDP) in Cranfield University. Started from conceptual design in the GDP, a high-aspect-ratio and large sweepback angle flying wing configuration has been adopted. During the GDP, the author was responsible for the structural layout design and material selection. Composite material has been chosen as the preferable material for both the inner and outer wing components. Based on the derivation of structural design data in the conceptual phase, the author continued with the preliminary design of the outer wing airframe and then focused on the optimization of the composite wing structure. Cont/d
Jie dian cai liao jie mian fu jin de ju yu chang fen bu
No full textCheung Wing Yi = 介電材料界面附近的局域場分佈 / 張詠怡.Thesis submitted in: October 2004.Thesis (M.Phil.)--Chinese University of Hong Kong, 2005.Includes bibliographical references (leaves 81-85).Text in English; abstracts in English and Chinese.Cheung Wing Yi = Jie dian cai liao jie mian fu jin de ju yu chang fen bu / Zhang Yongyi.Chapter 1 --- Introduction --- p.2Chapter 2 --- Fundamentals --- p.10Chapter 2.1 --- Local Field --- p.10Chapter 2.2 --- Clausius-Mossotti Equation --- p.12Chapter 3 --- Multi-layer Formulation --- p.14Chapter 3.1 --- Developed Lekner Summation Method --- p.15Chapter 3.2 --- Formulation --- p.16Chapter 3.2.1 --- Interlayers --- p.16Chapter 3.2.2 --- Multi-layers --- p.22Chapter 3.3 --- Comparision with Ewald-Kornfeld Formulation --- p.26Chapter 3.4 --- Contact with macroscopic concepts --- p.30Chapter 4 --- Local Field Distribution near Sharp Interfaces --- p.32Chapter 4.1 --- Body-centered Tetragonal Lattices --- p.33Chapter 4.2 --- Simple Tetragonal and Body-centered Tetragonal Lattices --- p.39Chapter 4.3 --- Effects of Geometric Anisotropy --- p.43Chapter 5 --- Local Field Distribution for Graded Materials --- p.52Chapter 5.1 --- Bare Polarizability Gradient --- p.53Chapter 5.2 --- Temperature Gradient --- p.58Chapter 6 --- Optical Response for Drude Dielectric Gradation Profile --- p.63Chapter 7 --- Summary --- p.72Chapter A --- Lekner summation method --- p.74Chapter B --- Ewald-Kornfeld Formulation --- p.78Chapter C --- Langevin-Debye Equation --- p.8
Optimal design of a flying-wing aircraft inner wing structure configuration
No full textFlying-wing aircraft are considered to have great advantages and potentials in
aerodynamic performance and weight saving. However, they also have many
challenges in design. One of the biggest challenges is the structural design of
the inner wing (fuselage). Unlike the conventional fuselage of a tube
configuration, the flying-wing aircraft inner wing cross section is limited to a
noncircular shape, which is not structurally efficient to resist the internal
pressure load. In order to solve this problem, a number of configurations have
been proposed by other designers such as Multi Bubble Fuselage (MBF),
Vaulted Ribbed Shell (VLRS), Flat Ribbed Shell (FRS), Vaulted Shell
Honeycomb Core (VLHC), Flat Sandwich Shell Honeycomb Core (FLHC), Y
Braced Box Fuselage and the modified fuselage designed with Y brace
replaced by vaulted shell configurations. However all these configurations still
inevitably have structural weight penalty compared with optimal tube fuselage
layout. This current study intends to focus on finding an optimal configuration
with minimum structural weight penalty for a flying-wing concept in a preliminary
design stage.
A new possible inner wing configuration, in terms of aerodynamic shape and
structural layout, was proposed by the author, and it might be referred as
‘Wave-Section Configuration’. The methodologies of how to obtain a structurally
efficient curvature of the shape, as well as how to conduct the initial sizing were
incorporated.
A theoretical analysis of load transmission indicated that the Wave-Section
Configuration is feasible, and this was further proved as being practical by FE
analysis. Moreover, initial FE analysis and comparison of the Wave-Section
Configuration with two other typical configurations, Multi Bubble Fuselage and
Conventional Wing, suggested that the Wave-Section Configuration is an
optimal design in terms of weight saving. However, due to limitations of the
author’s research area, influences on aerodynamic performances have not yet
been taken into account
Influence of wing kinematics on aerodynamic performance in hovering insect flight
No full textThe influence of different wing kinematic models on the aerodynamic performance of a hovering insect is investigated by means of two-dimensional time-dependent Navier–Stokes simulations. For this, simplified models are compared with averaged representations of the hovering fruit fly wing kinematics. With increasing complexity, a harmonic model, a Robofly model and two more-realistic fruit fly models are considered, all dynamically scaled at Re = 110. To facilitate the comparison, the parameters of the models were selected such that their mean quasi-steady lift coefficients were matched. Details of the vortex dynamics, as well as the resulting lift and drag forces, were studied. The simulation results reveal that the fruit fly wing kinematics result in forces that differ significantly from those resulting from the simplified wing kinematic models. In addition, light is shed on the effect of different characteristic features of the insect wing motion. The angle of attack variation used by fruit flies increases aerodynamic performance, whereas the deviation is probably used for levelling the forces over the cycle.Aerospace Design, Integration and OperationsAerospace Engineerin
Table1_Prescription characteristics of Xue-Fu-Zhu-Yu-Tang in pain management: a population-based study using the National Health Insurance Research Database in Taiwan.DOCX
No full textObjective: To explore the prevalence and distinctive features of Xue-Fu-Zhu-Yu-Tang (XFZYT) prescriptions by analyzing the National Health Insurance Research Database (NHIRD) to identify the specific medical problems for which XFZYT is prescribed.Methods: This nationwide, population-based, cross-sectional study included 109,073 XFZYT users and 532,848 XFZYT non-users among Chinese herbal product (CHP) users in NHIRD. Chi-squared tests were used to analyze disparities between the XFZYT user and XFZYT non-user cohorts, and the mean age was evaluated using the Wilcoxon rank-sum test. Logistic regression was used to compute the odds ratios (ORs) and 95% confidence intervals (95% CIs).Results: XFZYT was frequently used to treat pain. The top five conditions for which the Taiwanese traditional Chinese medicine (TCM) practitioners would prescribe XFZYT were chest pain; headache; myalgia and myositis; lumbago; and neuralgia, neuritis, and radiculitis.Conclusion: This study represents an inaugural comprehensive survey conducted on the utilization of XFZYT prescriptions among patients with diverse diseases. XFZYT is mostly used to treat pain conditions in Taiwan. Combined with the combination use of other CHPs, XFZYT is used to treat symptoms of the chest and respiratory system, soft tissue conditions, menstruation disorders, and joint and back discomfort. These results suggest that further clinical trials are warranted to verify the effects of XFZYT in pain management.</p
Analysis of composite wing structures with a morphing leading edge
No full textOne of the main challenges for the civil aviation industry is the reduction of its environmental impact. Over the past years, improvements in performance efficiency have been achieved by simplifying the design of the structural components and using composite materials to reduce the overall weight. These approaches however, are not sufficient to meet the current demanding requirements set for a „greener‟ aircraft.
Significant changes in drag reduction and fuel consumption can be obtained by using new technologies, such as smart morphing structures. These concepts will in fact help flow laminarisation, which will increase the lift to drag ratio. Furthermore, the capability to adapt the wing shape will enable to optimise the aerodynamic performance not only for a single flight condition but during the entire mission. This will significantly improve the aircraft efficiency.
The current research work has been carried out as part of the European Commission founded Seventh Framework Program called „Smart High Lift Device for the Next Generation Wing‟ (SADE), which main aim is to develop and study morphing high lift devices. The author‟s investigation focused on developing a design concept for the actuation mechanism of a morphing leading edge device. A detailed structural analysis has been carried out in order to demonstrate its feasibility.In the first phase of the research the attention was directed on the preliminary design and analysis of the composite wing box. The parameters of the key structural components, such as skin, spars, ribs and stringers were set to satisfy the static stress and buckling requirements. Moreover, numerical and experimental studies were conducted to analyse the static failure and buckling behaviour of two typical composite wing structural components: a spar section and a web and base joint assembly.
In the second stage of the research, a design for the morphing leading edge actuation mechanism was developed. The actuation system was designed in such a way that the target shape was reached with minimum actuation force demand. A geometrical nonlinear FE analysis was conducted to simulate the leading edge morphing deflection and ensure that structural strength requirements were satisfied. Furthermore, the behaviour of the skin integrated with the internal actuation mechanism was modelled under the aerodynamic pressure, at different flight conditions and gust loads, in order to prove that the proposed actuation system can compete with the conventional rigid rib.
This study demonstrated that a feasible morphing leading edge design for a next generation large aircraft wing can be achieved. Developing the readiness of this technology will have a significant impact on aircraft efficiency and considerable contribution towards a more environmental friendly aviation
Zheng Xuan-Fu Editions of Yu Tai Xin Yong
No full textThe Yu Tai Xin Yong (玉臺新詠) edition printed by Zheng Xuan-Fu (鄭玄撫) in the Jiajing period (嘉靖) in the 19th year of the Ming Dynasty (明代) is the foundational edition in Zheng Xuan-Fu editions (鄭玄撫系統), one of the two major editions of Yu Tai Xin Yong. Zheng’s edition of the Yu Tai Xin Yong was compiled and edited by Zheng Xuan-Fu based on an incomplete edition and a handwritten copy, differing from the other major editions of Yu Tai Xin Yong, Chen Yu-Fu editions (陳玉父系統), therefore contains information not present in the Chen editions and holds unique textual value. Another significant aspect of Zheng’s edition is that it reintroduced Yu Tai Xin Yong to the public eye, greatly influencing its transmission. The editions circulated during the Ming Dynasty primarily belong to Zheng’s editions. However, there is considerable confusion and error in the current records of ancient books that the supposedly Jiajing period Xu Xue-Mo (徐學謨)’s Hai Shu Lou (海曙樓) edition is actually a Wanli (萬曆) period reprint that omits information about Zheng’s original carving, which does not affect Zheng’s edition’s status as the original and authoritative Ming edition. Additionally, the so-called Jiajing 22nd year Yang Shi-Kai (楊士開)’s edition, claiming to be based on a Song Dynasty edition (宋本), is actually a recarved (挖改) print derived from Xu’s edition, with no genuine connection to the Song source. (Article content in Chinese with English extended abstract
Zhu pi shang yu
No full text[雍正批 ; 鄂爾泰等輯].綫裝, 16函.框21x16.2公分, 10行21字, 小字雙行, 無界行. 白口, 四周雙邊, 單黑魚尾. 版心上鐫"硃批諭旨", 中鐫葉次, 下記上奏臣工姓名. 行間有朱墨批點.題名據版心.內府活字硃墨套印本.前有雍正十年御製序.見《香港中文大學圖書館古籍善本書錄》(2001, p. 62)鈐"朝徹書屋", "南海劉氏", "劉安溥湖涵之章", "蓄素守巾"等印.Xian zhuang, 16 han.Kuang 21 x 16.2 gong fen, 10 hang 21 zi, xiao zi shuang hang, wu jie hang. Bai kou, si zhou shuang bian, dan hei yu wei. Ban xin shang juan "Zhu pi yu zhi", zhong juan ye ci, xia ji shang zou chen gong xing ming. Hang jian you zhu mo pi dian.Ti ming ju ban xin.Nei fu huo zi zhu mo tao yin ben.Qian you Yongzheng shi nian yu zhi xu.Jian "Xianggang Zhong wen da xue tu shu guan gu ji shan ben shu lu" (2001, p. 62)[Yongzheng pi ; E'ertai deng ji].Qian "Zhao che shu wu", "Nan hai Liu shi", "Liu Anpu hu han zhi zhang", "Xu su shou jin" deng yin
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