73,138 research outputs found
Li han lin quan ji: si shi er juan, mu lu si juan, nian pu. v.1
No full text[李白].綫裝, 1函.框20.3x14.8公分, 9行18字, 小字雙行同. 白口, 左右雙邊, 單白魚尾. 版心中鐫"李集"及卷次, 下鐫葉次.書根印有"李翰林集"前有王樨登序, 李陽冰《李翰林詩序》, 樂史《別集序》, 宋敏求後序, 曾鞏後序, 毛漸題跋.書中樂史《別集序》載"李翰林歌詩李陽冰纂為草堂集十卷史又別收歌詩十卷與草堂集互有得失因校勘排為二十卷號曰李翰林集"With: 李翰林年譜 / 薛仲邕編 ; 舊唐書列傳 ; 新唐書列傳 ; 李翰林墓誌銘 / 李華 ; 碣記 / 劉全 ; 碑陰記 / 蘇軾.Xian zhuang, 1 han.Kuang 20.3 x 14.8 gong fen, 9 hang 18 zi, xiao zi shuang hang tong. Bai kou, zuo you shuang bian, dan bai yu wei. Ban xin zhong juan "Li ji"ji juan ci, xia juan ye ci.Shu gen yin you "Li han lin ji"Qian you Wang Xideng xu, Li Yangbing "Li han lin shi xu", Yue Shi "Bie ji xu", Song Minqiu hou xu, Zeng Gong hou xu, Mao Jian ti ba.Shu zhong Yue Shi "Bie ji xu" zai "Li han lin ge shi Li Yangbing zuan wei Cao tang ji shi juan shi you bie shou ge shi shi juan yu Cao tang ji hu you de shi yin jiao kan pai wei er shi juan hao yue Li han lin ji"[Li Bai].With: Li han lin nian pu / Xue Zhongyong bian ; Jiu Tang shu lie zhuan ; Xin Tang shu lie zhuan ; Li han lin mu zhi ming / Li Hua ; Jie ji / Liu Quan ; Bei yin ji / Su Shi
Model predictive control of NPC inverters for different scenarios
No full textMultilevel inverters have undergone a period of rapid development recently and, as a result of the progression of contemporary industry, a range of commercial applications have attained the megawatt standard, thereby meaning that there is a requirement for medium- or high-power conversion mechanisms. At the same time, several energygenerating technologies that can be renewed including solar power, bio-energy, tidal power, wind power, and geothermal power have emerged as critical areas of development in global energy production initiatives, hence creating a situation where the multilevel inverter is becoming increasingly investigated by scholars. It is possible to use multilevel inverters with renewable energy sources and, at the same time, these devices can contribute to high-power rating standards. In light of these considerations, the purpose of the present thesis is to address the control algorithms of multilevel inverters and, to be specific, the thesis will chiefly examine the neutral point clamped (NPC) inverters. The main challenge regarding the modulation and control of NPC inverters is that the entire system is nonlinear due to the utilisation of power switches. Conventional approaches are mainly based on the average state space modelling and related modulation techniques such as pulse width modulation (PWM) and sinusoidal pulse width modulation (SPWM). However, the limitations of these conventional methods are clear. The model must be linearised based on a specific operating point. The tuning procedure of the controller is complex, and this complexity increases yet further when the operating point is adjusted. Due to the development of the fast microprocessor and digital signal processors (DSP), some novel control methods such as hysteresis current control, sliding mode control and model predictive control (MPC) have been applied to NPC inverters. Among these methods, MPC stands out for its fast response and handling multiple constraints, and MPC has achieved great success in power electronics applications. Therefore, novel MPC algorithms for 3-level NPC inverters have been proposed to improve energy efficiency for different scenarios in this thesis. Firstly, an MPC algorithm with reduced switching frequency for 3-level NPC inverters is proposed. The proposed method can reduce the switching frequency through the optimisation of switching sequences while keeping the advantages of the conventional MPC method, such as its fast response and ability to handle multiple constraints. The performance of this proposed method is verified by simulation results with 3-level NPC inverters. Based on this MPC algorithm, two additional extended MPC algorithms are proposed to reduce computational burden, including a multistep model predictive control (MMPC) algorithm and a model predictive control algorithm for grid-connected NPC inverters. The effectiveness of the proposed MPC algorithms has been identified.Furthermore, an MPC algorithm for NPC grid-connected inverters is proposed with automatic selection of weighting factors. The main objective of this proposed algorithm is to reduce switching frequency and to provide for the automatic selection of weighting factors without the need for trial and-error across different working conditions. The algorithm can also achieve active power tracking and maintain neutral point balancing. These various objectives are achieved through the use of a modified three-part cost function and the adoption of a two-dimensional fuzzy logic control scheme. The effectiveness of the proposed algorithm is verified using the results of grid-connected NPC inverters simulations, which show that the switching frequency can be reduced by at least 30% when compared to conventional MPC methods. In addition, a new proposed current slope-related control objective is added to the cost function of the proposed MPC algorithm. This control objective aims to make predicted slope values approach slope reference values. By doing this, the proposed algorithm can reduce the total harmonic distortion (THD) of the output currents and, when compared to a conventional MPC algorithm, can reduce the switching frequency by more than 30%. A case study of a grid-connected NPC inverter system is used to assess the effectiveness of the proposed MPC algorithm under conditions of nominal operation and dynamic operation (with the active power reference, P∗, being stepped down from 31kW to 24kW at 0.3s, then increased to 41kW at 0.5s) and with different degrees of parameter sensitivity (at +25%, +50%, and −75% variation in inductance)
Li shi yin jian : [6 juan /
No full textLi shi yin jian shu mu Hong Diyuan bian: ℓ. 1-13 at end of v. 4.Mode of access: Internet
Sen-Lab-LMS/Senescence_nuclear_features: Publication_version_2.0
No full text<p>Author checklist.</p>
Estimation of evapotranspiration in the Mu Us Sandland of China
No full textEvapotranspiration (ET) was estimated from 1981–2005 over Wushen County located in the Mu Us Sandland, China, by applying the Advection-Aridity model, which is based on the complementary relationship hypothesis. We used National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR), Moderate Resolution Imaging Spectroradiometer (MODIS), and meteorological data. Our results show that the estimated daily ET was about 4.5% higher than measurements using an Eddy Covariance (EC) system after forcing energy balance closure over an alfalfa field from 22 July 2004 to 23 August 2004. At a regional scale, the estimated monthly ET was about 8.7% lower than measurements using the EC system after forcing energy balance closure over an alfalfa field in August 2004. These results were about 3.0% higher than ET measurements by microlysimeter over sand dunes during June 1988. From 1981 to 2005, the average annual ET and precipitation levels were 287 mm and 336 mm, respectively, in Wushen County. The average annual ET varied from 230 mm in western parts of Wushen County to 350 mm in eastern parts of the county. Both inter-annual and seasonal variations in ET were substantial in Wushen County. The annual ET was 200–400 mm from 1981–2005, and the seasonal pattern of ET showed a single peak distribution. The cumulative ET during the June–September 2004 period was 250 mm, which was 87% of the total annual ET. The annual ET, precipitation, and the maximum Normalized Difference Vegetation Index (NDVI<sub>max</sub>) showed positive correlations temporally and spatially
NOMA-Aided Joint Radar and Multicast-Unicast Communication Systems
No full textThe novel concept of non-orthogonal multiple access (NOMA) aided joint radar
and multicast-unicast communication (Rad-MU-Com) is investigated. Employing the
same spectrum resource, a multi-input-multi-output (MIMO) dual-functional
radar-communication (DFRC) base station detects the radar-centric users
(R-user), while transmitting mixed multicast-unicast messages both to the
R-user and to the communication-centric user (C-user). In particular, the
multicast information is intended for both the R- and C-users, whereas the
unicast information is only intended for the C-user. More explicitly, NOMA is
employed to facilitate this double spectrum sharing, where the multicast and
unicast signals are superimposed in the power domain and the superimposed
communication signals are also exploited as radar probing waveforms. First, a
beamformer-based NOMA-aided joint Rad-MU-Com framework is proposed for the
system having a single R-user and a single C-user. Based on this framework, the
unicast rate maximization problem is formulated by optimizing the beamformers
employed, while satisfying the rate requirement of multicast and the predefined
accuracy of the radar beam pattern. The resultant non-convex optimization
problem is solved by a penalty-based iterative algorithm to find a high-quality
near-optimal solution. Next, the system is extended to the scenario of multiple
pairs of R- and C-users, where a cluster-based NOMA-aided joint Rad-MU-Com
framework is proposed. A joint beamformer design and power allocation
optimization problem is formulated for the maximization of the sum of the
unicast rate at each C-user, subject to the constraints on both the minimum
multicast rate for each R&C pair and on accuracy of the radar beam pattern for
detecting multiple R-users. The resultant joint optimization problem is
efficiently solved by another penalty-based iterative algorithm developed.Comment: 14 pages, 12 figures, this work is accepeted for the publication in
IEEE Journal on Selected Areas in Communication
Xilithus xiaojing Liu & Li 2022
No full textXilithus xiaojing Liu & Li, 2022 (ṁĦẇdzff) Figs 85–86 Acrolithus xiaojing Liu & Li, 2022: 354, Suppl. 2: 15, figs 14A–F, 15A–H, 16A–D, 20E. Xilithus xiaojing Lin, Li & Pham, 2023: 57. Material examined. 1 ♁ 2♀, CHINA: Hunan Province: Chenzhou City, Rucheng County, Jiulongjiang National Forest Park, Qinglong Gorge Scenic Spot (25.394029°N, 113.785765°E, 300 m a.s.l.), 12 May 2018, leg. Yannan Mu. Diagnosis. See Liu et al. 2022a. Description. See Liu et al. 2022a. Habitus and genitalia in Figs 85–86. Distribution. China (Hunan and Jiangxi provinces). Remark. This species is recorded from Hunan Province for the first time.Published as part of Mu, Yannan & Zhang, Feng, 2023, 5338, pp. 1-104 in Zootaxa 5338 (1) on pages 100-101, DOI: 10.11646/zootaxa.5338.1.1, http://zenodo.org/record/828373
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