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DPP);分布式功率转换器;开关电容转换器 1

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四元数傅里叶变换;四元数线性正则变换;采样定理;部分和总体四元数希尔伯特变换;部分和总体广义四元数希尔伯特变换;截断误差 1

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Optimal Su-Do-Ku based interconnection scheme for increased power output from PV array under partialshading conditions

P. SRINIVASA RAO,P. DINESH,G. SARAVANA ILANGO,C. NAGAMANI

《能源前沿(英文)》 2015年 第9卷 第2期   页码 199-210 doi: 10.1007/s11708-015-0350-1

摘要: Partial shading is a common phenomenon in PV arrays. They drastically reduce the power output because of mismatch losses, which are reliant on the shape of the shade as well as the locations of shaded panels in the array. The power output can be improved by distributing the shade over various rows to maximize the current entering the node. A Su-Do-Ku configuration can be used to rearrange the physical locations of the PV modules in a total cross tied PV array with the electrical connections left unchanged. However, this arrangement increases the length of the wire required to interconnect the panels thus increasing the line losses. In this paper, an improved Su-Do-Ku arrangement that reduces the length of the wire required for the connection is proposed. The system is designed and simulated in a Matlab/Simulink environment for various shading patterns and the efficacies of various arrangements are compared. The results prove that the power output is higher in the proposed improved Su-Do-Ku reconfiguration technique compared to the earlier proposed Su-Do-Ku technique.

关键词: array configuration     mismatch losses     partial shading     line losses     Su-Do-Ku arrangement    

Performance enhancement of partially shaded solar PV array using novel shade dispersion technique

Namani RAKESH,T. Venkata MADHAVARAM

《能源前沿(英文)》 2016年 第10卷 第2期   页码 227-239 doi: 10.1007/s11708-016-0405-y

摘要: Solar photo voltaic array (SPVA) generates a smaller amount of power than the standard rating of the panel due to the partial shading effect. Since the modules of the arrays receive different solar irradiations, the P-V characteristics of photovoltaic (PV) arrays contain multiple peaks or local peaks. This paper presents an innovative method (magic square) in order to increase the generated power by configuring the modules of a shaded photovoltaic array. In this approach, the physical location of the modules in the total cross tied (TCT) connected in the solar PV array is rearranged based on the magic square arrangement pattern. This connection is done without altering any electrical configurations of the modules in the PV array. This method can distribute the shading effect over the entire PV array, without concentrating on any row of modules and can achieve global peaks. For different types of shading patterns, the output power of the solar PV array with the proposed magic square configuration is compared with the traditional configurations and the performance is calculated. This paper presents a new reconfiguration technique for solar PV arrays, which increases the PV power under different shading conditions. The proposed technique facilitates the distribution of the effect of shading over the entire array, thereby, reducing the mismatch losses caused by partial shading. The theoretical calculations are tested through simulations in Matlab/Simulink to validate the results. A comparison of power loss for different types of topologies under different types of shading patterns for a 4 × 4 array is also explained.

关键词: photovoltaic cells     mismatch loss     shading patterns     partial shading     magic square     power enhancement     global peaks and total cross tied (TCT)    

Methanation and chemolitrophic nitrogen removal by an anaerobic membrane bioreactor coupled partial nitrification

《环境科学与工程前沿(英文)》 2023年 第17卷 第6期 doi: 10.1007/s11783-023-1668-2

摘要:

● Efficient carbon methanation and nitrogen removal was achieved in AnMBR-PN/A system.

关键词: Anaerobic membrane bioreactor     Partial nitrification/Anammox     Carbon separation     Chemolitrophic nitrogen removal    

Partial pressures” of humid air in wide pressure and temperature ranges

Zidong WANG, Hanping CHEN, Shilie WENG

《能源前沿(英文)》 2013年 第7卷 第4期   页码 511-517 doi: 10.1007/s11708-013-0281-7

摘要: “Partial pressure” in humid air is a question very much concerned by scientists and no satisfactory answer has been found to date. This paper proposes a novel method to obtain the “partial pressures” of the water vapor and dry air in humid air. The results obtained by the proposed method are quite different from that obtained by Dalton’s partial pressure law. The fundamental behaviors of water vapor and dry air are studied in depth in wide pressure and temperature ranges. Semi-permeable membrane models are proposed and applied for both saturated and unsaturated humid air. “Improvement factors” are developed to quantitatively describe the magnitude of the interaction between dissimilar molecules. One discovery is that the “partial pressure” of the water vapor in saturated humid air equals , rather than ( · ) which was formerly believed. The other is that the interaction between dissimilar molecules may be omitted when temperature is above “cutting-off temperature” for unsaturated humid air. This paper satisfactorily answers the quest of “partial pressures” in humid air from a new perspective.

关键词: partial pressure     Dalton’s partial pressure law     humid air     saturated     unsaturated    

Upper bound solution to seismic active earth pressure of submerged backfill subjected to partial drainage

《结构与土木工程前沿(英文)》 2021年 第15卷 第6期   页码 1480-1493 doi: 10.1007/s11709-021-0776-y

摘要: In waterfront geotechnical engineering, seismic and drainage conditions must be considered in the design of retaining structures. This paper proposes a general analytical method to evaluate the seismic active earth pressure on a retaining wall with backfill subjected to partial steady seepage flow under seismic conditions. The method comprises the following steps: i) determination of the total head, ii) upper bound solution of seismic active earth thrust, and iii) deduction for the earth pressure distribution. The determination of total head h(x,z) relies on the Fourier series expansions, and the expressions of the seismic active earth thrust and pressure are derived by using the upper bound theorem. Parametric studies reveal that insufficient drainage and earthquakes are crucial factors that cause unfavorable earth pressure. The numerical results confirm the validity of the total head distribution. Comparisons indicate that the proposed method is consistent with other relevant existing methods in terms of predicting seismic active earth pressure. The method can be applied to the seismic design of waterfront retaining walls.

关键词: seismic active earth pressure     partial seepage flow     pore pressure     anisotropy     upper bound theorem    

Methane partial oxidation over NiO-MgO/Ce

Piyawat PUE-ON, Vissanu MEEYOO, Thirasak RIRKSOMBOOON

《化学科学与工程前沿(英文)》 2013年 第7卷 第3期   页码 289-296 doi: 10.1007/s11705-013-1345-2

摘要: Methane partial oxidation (MPO) is considered as an alternative method to produce hydrogen because it is an exothermic reaction to afford a suitable H /CO ratio of 2. However, carbon deposition on a catalyst is observed as a major cause of catalyst deactivation in MPO. In order to find suitable catalysts that prevent the carbon deposition, NiO-MgO/Ce Zr O (CZO) supported catalysts were prepared via the co-impregnation (C) and sequential incipient wetness impregnation (S) methods. The amount of Ni loading was fixed at 15 wt-% whereas the amount of MgO loading was varied from 5 to 15 wt-%. The results revealed that the addition of MgO shifted the light-off temperatures to higher temperatures. This is because the Ni surface was partially covered with MgO, and the strong interaction between NiO and NiMgO over CZO support led to the difficulty in reducing NiO to active Ni and thus less catalytic activity. However, among the catalysts tested, the 15Ni5Mg/CZO (S) catalyst exhibited the best catalytic stability for MPO after 18 h on stream at 750°C. Moreover, this catalyst had a better resistance to carbon deposition due to its high metallic Ni dispersion at high temperature.

关键词: methane partial oxidation     NiO     ceria-zirconia     MgO     mixed oxide solid solution    

一种新型的部分遮挡和非匹配条件下最大功率点跟踪光伏子模块级功率平衡拓扑结构 Article

Mustafa GOKDAG,Mehmet AKBABA

《信息与电子工程前沿(英文)》 2016年 第17卷 第12期   页码 1388-1396 doi: 10.1631/FITEE.1500322

摘要: 部分遮挡和串联模块(或子模块)的非匹配条件可在整个光伏系统中导致功率曲线非凸且出现多个局部极值和峰值功率下降的现象。通过功率传输,可将各子模块的工作电压拉平;这样的功率收集操作可生成凸功率曲线,提升光伏系统的峰值功率。本文所述拓扑结构受益于开关电容(Switched capacitor, SC)转换器的概念,是一种子模块级功率平衡概念的具体应用。与现有研究成果相比,其创新点包含无遮挡时停止开关操作、串联线路级可拓展性以及减少功率电子元件使用量。功率电子元件使用量的减少是通过两个子模块共享一个SC转换器的方式实现的,这也能带来降低功率器件能量损耗、降低成本和电路体积的优势。本文给出了所述拓扑结构的插入损耗的理论式,并通过PSpice仿真和原型电路的实验评估,证明了损耗理论解的正确性。这也表明,通过使用所述拓扑结构,有可能提取出部分遮挡的光伏线路的几乎所有可用能量,并将其传输至负载端。

关键词: 子模块级最大功率点跟踪(Sub-module-level maximum power point tracking     MPPT);差分功率处理(Differential power processing     DPP);分布式功率转换器;开关电容转换器    

Enhanced nutrients removal from municipal wastewater through biological phosphorus removal followed by partial

Yandong Yang,Liang Zhang,Hedong Shao,Shujun Zhang,Pengchao Gu,Yongzhen Peng

《环境科学与工程前沿(英文)》 2017年 第11卷 第2期 doi: 10.1007/s11783-017-0911-0

摘要: EBPR and PN/A were combined to enhance nutrients removal from municipal wastewater. High effluent quality of 0.25 mg TP?L and 10.8 mg TN?L was obtained. Phosphorus and nitrogen removal was achieved in two separated units. A proper post-anoxic phase improved the nitrogen removal performance of PN/A unit. Conventional biological removal of nitrogen and phosphorus is usually limited due to the lack of biodegradable carbon source, therefore, new methods are needed. In this study, a new alternative consisting of enhanced biological phosphorus removal (EBPR) followed by partial nitritation-anammox (PN/A), is proposed to enhance nutrients removal from municipal wastewater. Research was carried out in a laboratory-scale system of combined two sequencing batch reactors (SBRs). In SBR1, phosphorus removal was achieved under an alternating anaerobic-aerobic condition and ammonium concentration stayed the same since nitrifiers were washed out from the reactor under short sludge retention time of 2–3 d. The remaining ammonium was further treated in SBR2 where PN/A was established by inoculation. A maximum of nitrogen removal rate of 0.12 kg N?m ?d was finally achieved. During the stable period, effluent concentrations of total phosphorus and total nitrogen were 0.25 and 10.8 mg?L , respectively. This study suggests EBPR-PN/A process is feasible to enhance nutrients removal from municipal wastewater of low influent carbon source.

关键词: Phosphorus removal     Partial nitrification     Anammox     Municipal wastewater    

Partial liver transplantation

null

《医学前沿(英文)》 2011年 第5卷 第1期   页码 1-7 doi: 10.1007/s11684-010-0105-7

摘要:

Partial liver transplantation, including reduced-size liver transplantation, split liver transplantation, and living donor liver transplantation, has been developed with several innovative techniques because of donor shortage. Reduced-size liver transplantation is based on Couinaud’s anatomical classification, benefiting children and small adult recipients but failing to relieve the overall donor shortage. Split liver transplantation provides chances to two or even more recipients when only one liver graft is available. The splitting technique must follow stricter anatomical and physiological criteria either ex situ or in situto ensure long-term quality. The first and most important issue involving living donor liver transplantation is donor safety. Before surgery, a series of donor evaluations—including anatomical, liver volume, and liver function evaluations—is indispensable, followed by ethnic agreement. At different recipient conditions, auxiliary liver transplantation and auxiliary partial orthotopic liver transplantation, which employ piggyback techniques, are good alternatives. Partial liver transplantation enriches the practice and knowledge of the transplant society.

关键词: partial liver transplantation     reduced-size liver transplantation     split liver transplantation     living donor liver transplantation    

Reduction kinetics of SrFeO/CaO∙MnO nanocomposite as effective oxygen carrier for chemical looping partial

《化学科学与工程前沿(英文)》 2022年 第16卷 第12期   页码 1726-1734 doi: 10.1007/s11705-022-2188-5

摘要: Chemical looping reforming of methane is a novel and effective approach to convert methane to syngas, in which oxygen transfer is achieved by a redox material. Although lots of efforts have been made to develop high-performance redox materials, a few studies have focused on the redox kinetics. In this work, the kinetics of SrFeO3−δ–CaO∙MnO nanocomposite reduction by methane was investigated both on a thermo-gravimetric analyzer and in a packed-bed microreactor. During the methane reduction, combustion occurs before the partial oxidation and there exists a transition between them. The weight loss due to combustion increases, but the transition region becomes less inconspicuous as the reduction temperature increased. The weight loss associated with the partial oxidation is much larger than that with combustion. The rate of weight loss related to the partial oxidation is well fitted by the Avrami–Erofeyev equation with n = 3 (A3 model) with an activation energy of 59.8 kJ∙mol‒1. The rate law for the partial oxidation includes a solid conversion term whose expression is given by the A3 model and a methane pressure-dependent term represented by a power law. The partial oxidation is half order with respect to methane pressure. The proposed rate law could well predict the reduction kinetics; thus, it may be used to design and/or analyze a chemical looping reforming reactor.

关键词: chemical looping reforming     SrFeO3−δ/CaO·MnO nanocomposite     reduction kinetics     Avrami–Erofeyev model     pressure-dependent term    

Tests on impact effect of partial fracture at steel frame connections

CHEN Yiyi, BIAN Ruoning

《结构与土木工程前沿(英文)》 2008年 第2卷 第4期   页码 295-301 doi: 10.1007/s11709-008-0049-z

摘要: Impact effect of sudden fracture at steel frame connections under severe earthquake or other extreme loads is presented in this paper. The relation of impulse caused by structural fracture to the release of inner force at the cracked location, the magnitude of the response to impact on the basis of one degree of freedom model, and the ratio of the peak value of response to natural period of the system are investigated. Two types of fracture tests were designed and carried out both on uniaxial steel bar tensioned and moment resistant steel frame model. It is proven that the response during the fracture process can be measured quite well using high-frequency data processing system. It is also revealed that the instant fracture of structural connection is characterized by progressive and partial fracture. Numerical evaluation of the impact effect of connection fracture is carried out.

关键词: structural fracture     natural     fracture     progressive     high-frequency    

Prospective research on the efficacy and safety of oxcarbazepine as monotherapy and add-on therapy for partial

Huicong KANG, Xiaoyan LIU, Hu QI, Feng XU, Xiang LI, Yuan WANG, Zhiguang LIU, Suiqiang ZHU

《医学前沿(英文)》 2009年 第3卷 第2期   页码 181-186 doi: 10.1007/s11684-009-0025-6

摘要: The purpose of our research was to evaluate the efficacy, tolerance, and safety of oxcarbazepine (OXC) as monotherapy and add-on therapy for partial epilepsy. We carried out a prospective clinical follow-up trial at the Epilepsy Center of Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology. Sixty-seven patients with partial epilepsy received OXC therapy. The patients were randomly divided into a monotherapy group and an add-on therapy group. We observed the efficacy and safety in the first three months and the following three months respectively, and compared them with each other. There was a significant difference in the decrease of seizure frequency between the two groups ( = 0.002). There was a significant difference in the percentage of seizure-free between the monotherapy and the add-on therapy groups in the first three months ( = 0.02), and there were also statistical differences in the 50% response rate ( = 0.017) and the percentage of seizure-free in the following three months ( = 0.019). No difference was found in the 50% response rate, the 75% response rate, and the percentage of seizure-free between the first three months and the following three months in the whole group and the two subgroups ( > 0.05). The incidence rate of side effects due to the therapy was 19.40% (13 of 67). The side effects were mainly found in the first three months. It is concluded that OXC is the first-line anti-epileptic drug (AED) for partial seizures, and could be used as the monotherapy and add-on therapy for newly diagnosed patients and patients that failed to tolerate or benefit from other AEDs.

关键词: oxcarbazepine     partial epilepsy    

Unveiling the interaction mechanisms of key functional microorganisms in the partial denitrification-anammox

《环境科学与工程前沿(英文)》 2023年 第17卷 第8期 doi: 10.1007/s11783-023-1703-3

摘要:

● The availability of PD-anammox was investigated with higher NO3–N concentration.

关键词: PD-anammox process     Nitrite accumulation     COD     Microbial interaction    

Crystal-to-crystal transformation from the triclinic to the cubic crystal system by partial desolvation

Qianqian Guo, Irmgard Kalf, Ulli Englert

《化学科学与工程前沿(英文)》 2018年 第12卷 第3期   页码 433-439 doi: 10.1007/s11705-018-1743-6

摘要:

Diffusion reaction of the labile building block Mg(acacCN)2 (acacCN= 3-cyanoacetylacetonate) with silver salts leads to a series of solvated Mg/Ag bimetallic coordination polymers with composition [Mg(acacCN)3Ag]·solvent. Despite their common stoichiometry, the topology of these polymers depends on the solvent of crystallization. The two-dimensional coordination compound [Mg(acacCN)3Ag]·4CHCl3 in space group P1‾ is obtained as platelet-shaped crystals from a mixture of methanol and chloroform. When kept in the reaction mixture, these thin plates within one week convert to isometric tetrahedral crystals of the 3D network [Mg(acacCN)3Ag]·2CHCl3 in the cubic space group P213. The transformation reaction proceeds via dissolution and recrystallization. The co-crystallized solvent molecules play an important role for stabilizing the target structure: They subtend Cl···Cl contacts and interact via non-classical C–H···O hydrogen bonds with the coordination framework. In the new cubic coordination network, both Mg(II) and Ag(I) adopt octahedral coordination, with unprecedented face-sharing by bridging O atoms of three acetylacetonato moieties. Prolonged standing of [Mg(acacCN)3Ag]·2CHCl3 in the reaction medium leads to further degradation, under formation of [Ag(acacCN)].

关键词: ditopic ligand     substituted acetylacetone     desolvation     diffraction    

nitrogen removal in low C/N ratio municipal wastewater through short-cut nitrification-denitrification and partial

Shengjie Qiu, Jinjin Liu, Liang Zhang, Qiong Zhang, Yongzhen Peng

《环境科学与工程前沿(英文)》 2021年 第15卷 第2期 doi: 10.1007/s11783-020-1318-x

摘要: Abstract • Sludge fermentation liquid addition resulted in a high NAR of 97.4%. • Extra NH4+-N from SFL was removed by anammox in anoxic phase. • Nitrogen removal efficiency of 92.51% was achieved in municipal wastewater. • The novel system could efficiently treat low COD/N municipal wastewater. Biological nitrogen removal of wastewater with low COD/N ratio could be enhanced by the addition of wasted sludge fermentation liquid (SFL), but the performance is usually limited by the introducing ammonium. In this study, the process of using SFL was successfully improved by involving anammox process. Real municipal wastewater with a low C/N ratio of 2.8–3.4 was treated in a sequencing batch reactor (SBR). The SBR was operated under anaerobic-aerobic-anoxic (AOA) mode and excess SFL was added into the anoxic phase. Stable short-cut nitrification was achieved after 46d and then anammox sludge was inoculated. In the stable period, effluent total inorganic nitrogen (TIN) was less than 4.3 mg/L with removal efficiency of 92.3%. Further analysis suggests that anammox bacteria, mainly affiliated with Candidatus_Kuenenia, successfully reduced the external ammonia from the SFL and contributed approximately 28%–43% to TIN removal. Overall, this study suggests anammox could be combined with SFL addition, resulting in a stable enhanced nitrogen biological removal.

关键词: Sludge fermentation liquid     Municipal wastewater     Advanced nitrogen removal     Short-cut nitrification     Partial anammox    

标题 作者 时间 类型 操作

Optimal Su-Do-Ku based interconnection scheme for increased power output from PV array under partialshading conditions

P. SRINIVASA RAO,P. DINESH,G. SARAVANA ILANGO,C. NAGAMANI

期刊论文

Performance enhancement of partially shaded solar PV array using novel shade dispersion technique

Namani RAKESH,T. Venkata MADHAVARAM

期刊论文

Methanation and chemolitrophic nitrogen removal by an anaerobic membrane bioreactor coupled partial nitrification

期刊论文

Partial pressures” of humid air in wide pressure and temperature ranges

Zidong WANG, Hanping CHEN, Shilie WENG

期刊论文

Upper bound solution to seismic active earth pressure of submerged backfill subjected to partial drainage

期刊论文

Methane partial oxidation over NiO-MgO/Ce

Piyawat PUE-ON, Vissanu MEEYOO, Thirasak RIRKSOMBOOON

期刊论文

一种新型的部分遮挡和非匹配条件下最大功率点跟踪光伏子模块级功率平衡拓扑结构

Mustafa GOKDAG,Mehmet AKBABA

期刊论文

Enhanced nutrients removal from municipal wastewater through biological phosphorus removal followed by partial

Yandong Yang,Liang Zhang,Hedong Shao,Shujun Zhang,Pengchao Gu,Yongzhen Peng

期刊论文

Partial liver transplantation

null

期刊论文

Reduction kinetics of SrFeO/CaO∙MnO nanocomposite as effective oxygen carrier for chemical looping partial

期刊论文

Tests on impact effect of partial fracture at steel frame connections

CHEN Yiyi, BIAN Ruoning

期刊论文

Prospective research on the efficacy and safety of oxcarbazepine as monotherapy and add-on therapy for partial

Huicong KANG, Xiaoyan LIU, Hu QI, Feng XU, Xiang LI, Yuan WANG, Zhiguang LIU, Suiqiang ZHU

期刊论文

Unveiling the interaction mechanisms of key functional microorganisms in the partial denitrification-anammox

期刊论文

Crystal-to-crystal transformation from the triclinic to the cubic crystal system by partial desolvation

Qianqian Guo, Irmgard Kalf, Ulli Englert

期刊论文

nitrogen removal in low C/N ratio municipal wastewater through short-cut nitrification-denitrification and partial

Shengjie Qiu, Jinjin Liu, Liang Zhang, Qiong Zhang, Yongzhen Peng

期刊论文