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Design and evaluation of control strategies in urban drainage systems in Kunming city

Xin Dong, Senchen Huang, Siyu Zeng

《环境科学与工程前沿（英文）》 2017年 第11卷 第4期 doi: 10.1007/s11783-017-0968-9

摘要： Real time control (RTC) of urban drainage systems (UDSs) is an important measure to reduce combined sewer overflow (CSO) and urban flooding, helping achieve the aims of ‘Sponge City’. Application of RTC requires three main steps: strategy design, simulation-based evaluation and field test. But many of published RTC studies are system-specific, lacking discussions on how to design a strategy step by step. In addition, the existing studies are prone to use hydrologic model to evaluated strategies, but a more precise and dynamic insight into strategy performance is needed. To fill these knowledge gaps, based on a case UDS in Kunming city, a study on RTC strategy design and simulation-based evaluation is performed. Two off-line volume-based RTC strategy design principles, and , are emphasized. Following these principles, a detailed design procedure is shown for the case UDS resulting in three RTC strategies: static, constant and equal filling. The proposed strategies are evaluated based on a hydrodynamic model- Storm Water Management Model (SWMM) - under four typical rainfall events characterized by different return periods (1-year or 0.5 year) and different spatial distributions (uniform or uneven). The equal filling strategy outperforms other two strategies and it can achieve 10% more CSO reduction and 5% more flooding reduction relative to the no-tank case.

关键词： Urban drainage system     Real time control     Static strategy     Constant strategy     Equal filling strategy    

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Research progress on low dielectric constant modification of cellulose insulating paper for power transformers

《化学科学与工程前沿（英文）》 2023年 第17卷 第8期   页码 991-1009 doi: 10.1007/s11705-022-2259-7

摘要： Because of the increase in the transmission voltage levels, the demand for insulation reliability of power transformers has increasingly become critical. Cellulose insulating paper is the main insulating component of power transformers. To improve the insulation level of ultrahigh voltage transformers and reduce their weight and size, reducing the dielectric constant of oil-immersed cellulose insulating paper is highly desired. Cellulose is used to produce power-transformer insulating papers owing to its excellent electrical properties, renewability, biodegradability and abundance. The dielectric constant of a cellulose insulating paper can be effectively reduced by chemical or physical modification. This study presents an overview of the foreign and domestic research status of the use of modification technology to reduce the dielectric constant of cellulose insulating papers. All the mentioned methods are analyzed in this study. Finally, some recommendations for future modified cellulose insulating paper research and applications are proposed. This paper can provide a reference for further research on low dielectric constant cellulose insulating paper in the future.

关键词： low dielectric constant     chemical and physical modification     cellulose insulating paper     transformer     nanomaterials.    

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Analysis and characterization of wind-solar-constant torque spring hybridized model

Shantanu ACHARYA,Subhadeep BHATTACHARJEE

《能源前沿（英文）》 2014年 第8卷 第3期   页码 279-289 doi: 10.1007/s11708-014-0312-z

摘要： Solar and wind are the most promising renewable energy resources. But their unpredictable and varying nature prevents them from being used as the sole resource for power generation. This paper presents a model of wind and solar thermal hybrid power plant with a spring storage system which is expected to play an efficient role in combating with the drawbacks related to renewable power generation. In the proposed scheme, wind energy is harnessed by a hybrid vertical axis wind turbine, solar energy is utilized by a Stirling engine, and the surplus energy is stored in a winding spring. The paper discusses the working methodologies and analyses the performance of such 2.6 kW hybrid power plant model. It has been observed that the plant is capable of consistently generating 50% of its rated capacity irrespective of limitations in solar and wind resources.

关键词： hybrid vertical axis wind turbine     Stirling engine     solar-thermal energy     wind energy     constant torque spring    

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Development of a fan-stirred constant volume combustion chamber and turbulence measurement with PIV

《能源前沿（英文）》 2022年 第16卷 第6期   页码 973-987 doi: 10.1007/s11708-021-0762-z

摘要： A fan-stirred combustion chamber is deve-loped for spherically expanding flames, with P and T up to 10 bar and 473 K, respectively. Turbulence characteristics are estimated using particle image velocimetry (PIV) at different initial pressures (P = 0.5–5 bar), fan frequencies (ω = 0–2000 r/min), and impeller diameters (D = 100 and 114 mm). The flame propagation of methanol/air is investigated at different turbulence intensities (u′=0–1.77 m/s) and equivalence ratios (φ = 0.7–1.5). The results show that u′ is independent of P and proportional to ω, which can be up to 3.5 m/s at 2000 r/min. LT is independent of P and performs a power regression with ω approximately. The turbulent field is homogeneous and isotropic in the central region of the chamber while the inertial subrange of spatial energy spectrum is more collapsed to –5/3 law at a high ReT. Compared to laminar expanding flames, the morpho-logy of turbulent expanding flames is wrinkled and the wrinkles will be finer with the growth of turbulence intensity, consistent with the decline of the Taylor scale and the Kolmogorov scale. The determined SL in the present study is in good agreement with that of previous literature. The SL and ST of methanol/air have a non-monotonic trend with φ while peak ST is shifted to the richer side compared to SL. This indicates that the newly built turbulent combustion chamber is reliable for further experimental study.

关键词： fan-stirred combustion chamber     turbulence characteristics     particle image velocimetry (PIV)     methanol     turbulent expanding flames    

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Solar photovoltaic fed dual input LED lighting system with constant illumination control

Kinattingal SUNDARESWARAN,Kevin Ark KUMAR,Payyalore Raman VENKATESWARAN,Sankaran PALANI

《能源前沿（英文）》 2016年 第10卷 第4期   页码 473-478 doi: 10.1007/s11708-016-0420-z

摘要： A dual input LED lighting scheme with constant illumination is proposed in this paper. The scheme employs a photovoltaic array as the first input and a battery as the second one. A microcontroller is programmed to operate a changeover switch as well as a DC-DC converter for uninterrupted and constant illumination in work place. The scheme is suitable for conference halls, laboratories, clean rooms, marriage halls, theaters, etc. The complete modeling, design and experimentation of the proposed scheme are explained and the economic viability of the scheme is justified.

关键词： photovoltaic     LED light     dual input     P&O algorithm    

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The energy consumption in a batch stripper and a batch rectifier

Xianbao CUI, Tianyang FENG, Ying ZHANG, Zhicai YANG,

《化学科学与工程前沿（英文）》 2009年 第3卷 第4期   页码 443-452 doi: 10.1007/s11705-009-0266-6

摘要： The energy consumption in a batch rectifier and a batch stripper was investigated with a shortcut mathematical model. The minimum energy consumption of a batch stripper was compared to that of a batch rectifier under “general constant reflux” and “general constant distillate composition” with the ratio of minimum energy consumption /. When the feed contains a large amount of light component, the product purity specification is low and the relative volatility is small, the minimum energy consumption of a batch stripper is less than that of a batch rectifier under “general constant reflux” and “general constant distillate composition”. When the feed contains a small amount of light component, the product purity specification is very high and the relative volatility is low, a batch stripper can also consume less energy only in the “general constant distillate composition” operation mode. In other cases, a batch rectifier can consume less energy.

关键词： constant reflux     feed     energy consumption     general constant     product purity    

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用经典力学计算氢分子的键长键能及力常数

陈景

《中国工程科学》 2003年 第5卷 第6期   页码 39-43

摘要：

氢原子中1 s电子的电子云呈球形，电子的最大几率密度分布出现在玻尔半径a0的球壳内，认为几率密度分布及电子云属统计规律，意味着已经使用了宏观时标，这样就使氢分子体系中能量和时间的作用量远大于普郎克常数；根据电子云的交叠，用经典力学计算了基态氢分子的结构常数，获得键长、键能及力常数的表达式分别为Re = 〓a0，De = ze/4〓a0,k = ze/2〓，采用原子单位（a.u.）时z、e及a0均为1，获得Re=1.414 a.u.，De=0.177 a.u.，k=0.354 a.u.，这些数值与实验值的相对误差分别<1%，<2%和<4%；成键模型直观，物理意义明确，计算中不含任何人为性参数。

关键词： 氢分子     键长     键能     力常数    

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新型双馈变速凸极同步电机

宁玉泉

《中国工程科学》 2004年 第6卷 第12期   页码 27-31

摘要：

提出一种新型双馈变速凸极同步电机，阐述了它的基本原理和结构，电机的转子采用分裂磁极和正交绕组, 结构简单、可靠。转子绕组由低频交流变频电源供电，使电机具有变速恒频的特性。通过原型样机的试验，验证了该项发明的正确性和实用性，它将在大型水电、风电中得到广泛应用。

关键词： 凸极同步电机 变速恒频 交流励磁 双馈    

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Constant temperature control of tundish induction heating power supply for metallurgical manufacturing

Yufei YUE, Qianming XU, Peng GUO, An LUO

《能源前沿（英文）》 2019年 第13卷 第1期   页码 16-26 doi: 10.1007/s11708-018-0572-0

摘要： The tundish induction heating power supply (TIHPS) is one of the most important equipment in the continuous casting process for metallurgical manufacturing. Specially, the constant temperature control is greatly significant for metallurgical manufacturing. In terms of the relationship between TIH load temperature and output power of TIHPS, the constant temperature control can be realized by power control. In this paper, a TIHPS structure with three-phase PWM rectifiers and full-bridge cascaded inverter is proposed. Besides, an input harmonic current blocking strategy and a load voltage feedforward control are also proposed to realize constant temperature control. To meet the requirement of the system, controller parameters are designed properly. Experiments are conducted to validate the feasibility and effectiveness of the proposed TIHPS topology and the control methods.

关键词： tundish induction heating power supply (TIHPS)     constant temperature control     input harmonic current blocking     load voltage feedforward    

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Seismic response of precast reinforced concrete wall subjected to cyclic in-plane and constant out-of-plane

《结构与土木工程前沿（英文）》 2021年 第15卷 第5期   页码 1128-1143 doi: 10.1007/s11709-021-0753-5

摘要： This paper provides insight into the seismic behavior of a full-scale precast reinforced concrete wall under in-plane cyclic loading combined with out-of-plane loading replicated by sand backfill to simulate the actual condition of basement walls. The tested wall exhibited flexural cracks, owing to the high aspect ratio and considerable out-of-plane movement due to lateral pressure from the backfill. The wall performed satisfactorily by exhibiting competent seismic parameters and deformation characteristics governed by its ductile response in the nonlinear phase during the test with smaller residual drift. Numerical analysis was conducted to validate experimental findings, which complied with each other. The numerical model was used to conduct parametric studies to study the effect of backfill density and aspect ratio on seismic response of the proposed precast wall system. The in-plane capacity of walls reduced, while deformation characteristics were unaffected by the increase in backfill density. An increase in aspect ratio leads to a reduction in in-plane capacity and an increase in drift. Curves between the ratio of in-plane yield capacity and design shear load of walls are proposed for the backfill density, which may be adopted to determine the in-plane yield capacity of the basement walls based on their design shear.

关键词： precast wall     basement wall     out-of-plane response     quasi-static test     sand backfill     seismic parameters    

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用于并网逆变器的改进三矢量无差拍模型预测直接功率控制策略 None

Chen-wen CHENG, Heng NIAN, Long-qi LI

《信息与电子工程前沿（英文）》 2018年 第19卷 第11期   页码 1420-1431 doi: 10.1631/FITEE.1601874

摘要： 用于并网逆变器的传统模型预测直接功率控制，在每个控制周期只使用一个逆变器电压矢量，导致并网电流和功率出现大量谐波分量，降低电能质量。为提高稳态性能，预测控制需要很高的采样频率，同时由于计算复杂，预测算法需要较长执行时间，二者存在矛盾。为解决这个问题，提出一种新的无差拍模型预测直接功率控制策略，在每个控制周期使用2个有效电压矢量和1个零电压矢量。采用三矢量策略保证开关频率恒定，提高电流和功率质量。不同于传统三矢量模型预测直接功率控制策略，该方法根据功率误差而非电网电压矢量位置选择三个矢量，保证矢量计算时间始终为正。同时，无需迭代计算，有利于在数字信号处理芯片上执行算法。最后，搭建1 kW逆变器实验平台，验证了该方法的有效性。

关键词： 并网逆变器；模型预测控制；直接功率控制；三矢量；恒定开关频率；功率误差    

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Convective heat transfer in helical coils for constant-property and variable-property flows with high

Yufei MAO, Liejin GUO, Bofeng BAI, Ximin ZHANG

《能源前沿（英文）》 2010年 第4卷 第4期   页码 546-552 doi: 10.1007/s11708-010-0116-8

摘要： Forced convection heat transfer of single-phase water in helical coils was experimentally studied. The testing section was constructed from a stainless steel round tube with an inner diameter of 10 mm, coil diameter of 300 mm, and pitch of 50 mm. The experiments were conducted over a wide Reynolds number range of 40000 to 500000. Both constant-property flows at normal pressure and variable-property flows at supercritical pressure were investigated. The contribution of secondary flow in the helical coil to heat transfer was gradually suppressed with increasing Reynolds number. Hence, heat transfer coefficients of the helical tube were close to those of the straight tube under the same flow conditions when the Reynolds number is large enough. Based on the experimental data, heat transfer correlations for both incompressible flows and supercritical fluid flows through helical coils were proposed.

关键词： convective heat transfer     helical coils     high Reynolds number     supercritical pressure     variable property    

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Deep eutectic solvent inclusions for high- composite dielectric elastomers

《化学科学与工程前沿（英文）》 2022年 第16卷 第6期   页码 996-1002 doi: 10.1007/s11705-022-2138-2

摘要： Recent advances in novel electroactive devices have placed new requirements on material development. High-performance dielectric elastomers with good mechanical stretchability and high dielectric constant are under high demand. However, the current strategy for fabricating these materials suffers from high cost or low thermal stability, which greatly hinders large-scale industrial production. Herein, we have successfully developed a novel strategy for improving the dielectric constant of polymeric elastomers via deep eutectic solvent inclusion by taking advantage of the low cost, convenient and environmentally benign synthesis process and high ionic conductivity from deep eutectic solvents. The as-prepared composite elastomers showed good stretchability and a greatly enhanced dielectric constant with a negligible increase in dielectric dissipation. Moreover, we have proven the universality of our strategy by using different types of deep eutectic solvents. It is believed that low-cost, easy-synthesis and environmentally friendly deep eutectic solvents including composite elastomers are highly suitable for large-scale industrial production and can greatly broaden the application fields of dielectric elastomers.

关键词： composite materials     deep eutectic solvent     dielectric elastomer     high dielectric constant    

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Removing ammonia from air with a constant pH, slightly acidic water　spray wet scrubber using recycled

Ahmad Kalbasi Ashtari, Amir M. Samani Majd, Gerald L. Riskowski, Saqib Mukhtar, Lingying Zhao

《环境科学与工程前沿（英文）》 2016年 第10卷 第6期 doi: 10.1007/s11783-016-0869-3

摘要： Slightly acidic solutions are a practical means of removing ammonia from air Scrubbed NH accumulates in solution as NH and should be an excellent fertilizer Increased air velocity decreased NH removal and increased NH collection Previous research on wet scrubbers has only studied highly acidic scrubbing solutions because of their high ammonia capture efficiencies; however, the high acidity created practical problems. Lower acidity solutions would reduce corrosion, maintenance, and cost; however, designers may need to use strategies for increasing scrubber effectiveness, such as using lower air velocities. The objective of this study was to determine if a spray scrubber with slightly acidic and higher pH scrubbing solution (pH from 2 to 8) could effectively remove NH from NH laden air (such as animal building exhaust air), and also collect this valuable resource for later use as a fertilizer. A bench-scale spray wet scrubber treated 20 ppmv NH /air mixture in a countercurrent contact chamber. First, the solution pH was varied from 2 to 8 while maintaining constant air velocity at 1.3 m·s . Next, air velocity was increased (2 and 3 m·s ) while solution pH remained constant at pH6. At 1.3 m·s , NH removal efficiencies ranged between 49.0% (pH8) and 84.3% (pH2). This study has shown that slightly acidic scrubbing solutions are a practical means of removing ammonia from air especially if the scrubber is designed to increase collisions between solution droplets and NH molecules. The NH removed from the air was held in solution as NH and accumulates over time so the solution should be an excellent fertilizer.

关键词： Ammonia     Spray wet scrubber     Slightly acidic scrubbing solution     Controlled pH     Removal efficiency    

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Pre-chamber turbulent jet ignition of methane/air mixtures with multiple orifices in a large bore constant

Xiang LI, Wenzheng ZHANG, Zhong HUANG, Dehao JU, Li HUANG, Mingzhi FENG, Xingcai LU, Zhen HUANG

《能源前沿（英文）》 2019年 第13卷 第3期   页码 483-493 doi: 10.1007/s11708-019-0631-1

摘要： Liquefied natural gas (LNG), mainly composed of methane, is in progress to substitute diesel fuel in heavy-duty marine engine for practical, economic, and environmental considerations. However, natural gas is relatively difficult to be ignited in a large bore combustion chamber. A combustion enhancement technique called pre-chamber turbulent jet ignition (TJI) can permit combustion and flame propagation in a large-bore volume. To investigate the effect of air-fuel equivalence ratio and pre-mixed pressure on pre-chamber TJI of methane/air mixtures with multiple orifices in a large bore volume, experimental tests and computational simulations were implemented to study the discharge of hot turbulent jets from six orifices of the pre-chamber. Different initial pressures and air-fuel equivalence ratios were considered to analyze the characteristics of TJI. The asymmetry of the turbulent jet actuated from six different orifices were found due to the asymmetric orientation of the spark plug, resulting in the inhomogeneous distribution of combustion in the constant volume chamber, which should be considered seriously in the marine engine design. Besides, as the premixed pressure increases, it has more effect on the flame propagation and plays a more important role, as it further increases.

关键词： marine engine     natural gas     methane     turbulent jet ignition (TJI)     pre-chamber    

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标题 作者 时间 类型 操作

Design and evaluation of control strategies in urban drainage systems in Kunming city

Xin Dong, Senchen Huang, Siyu Zeng

期刊论文

Research progress on low dielectric constant modification of cellulose insulating paper for power transformers

期刊论文

Analysis and characterization of wind-solar-constant torque spring hybridized model

Shantanu ACHARYA,Subhadeep BHATTACHARJEE

期刊论文

Development of a fan-stirred constant volume combustion chamber and turbulence measurement with PIV

期刊论文

Solar photovoltaic fed dual input LED lighting system with constant illumination control

Kinattingal SUNDARESWARAN,Kevin Ark KUMAR,Payyalore Raman VENKATESWARAN,Sankaran PALANI

期刊论文

The energy consumption in a batch stripper and a batch rectifier

Xianbao CUI, Tianyang FENG, Ying ZHANG, Zhicai YANG,

期刊论文

用经典力学计算氢分子的键长键能及力常数

陈景

期刊论文

新型双馈变速凸极同步电机

宁玉泉

期刊论文

Constant temperature control of tundish induction heating power supply for metallurgical manufacturing

Yufei YUE, Qianming XU, Peng GUO, An LUO

期刊论文

Seismic response of precast reinforced concrete wall subjected to cyclic in-plane and constant out-of-plane

期刊论文

用于并网逆变器的改进三矢量无差拍模型预测直接功率控制策略

Chen-wen CHENG, Heng NIAN, Long-qi LI

期刊论文

Convective heat transfer in helical coils for constant-property and variable-property flows with high

Yufei MAO, Liejin GUO, Bofeng BAI, Ximin ZHANG

期刊论文

Deep eutectic solvent inclusions for high- composite dielectric elastomers

期刊论文

Removing ammonia from air with a constant pH, slightly acidic water　spray wet scrubber using recycled

Ahmad Kalbasi Ashtari, Amir M. Samani Majd, Gerald L. Riskowski, Saqib Mukhtar, Lingying Zhao

期刊论文

Pre-chamber turbulent jet ignition of methane/air mixtures with multiple orifices in a large bore constant

Xiang LI, Wenzheng ZHANG, Zhong HUANG, Dehao JU, Li HUANG, Mingzhi FENG, Xingcai LU, Zhen HUANG

期刊论文