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2022 3

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2006 1

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同相/正交分量不平衡；正交频分复用；标准独立 1

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Unintended nutrient imbalance induced by wastewater effluent inputs to receiving water and its ecological

《环境科学与工程前沿（英文）》 2022年第16卷第11期 doi: 10.1007/s11783-022-1584-x

摘要： Eutrophication is the most widespread water quality issue globally. To date, most efforts to control eutrophication have focused on reductions of external nutrient inputs, yet importance of nutrient stoichiometry and subsequent shift in plankton composition in aquatic ecosystem has been largely neglected. To address eutrophication, improved sanitation is one of the United Nations Sustainable Development Goals, spurring the constructions of wastewater treatment facilities that have improved water quality in many lakes and rivers. However, control measures are often targeted at and effective in removing a single nutrient from sewage and thus are less effective in removing the others, resulting in the changes of nutrient stoichiometry. In general, more effective phosphorus removal relative to nitrogen has occurred in wastewater treatment leading to substantial increases in N/P ratios in effluent relative to the influent. Unfortunately, high N/P ratios in receiving waters can impose negative influences on ecosystems. Thus, long-term strategies for domestic wastewater management should not merely focus on the total reduction of nutrient discharge but also consider their stoichiometric balances in receiving waters.

关键词： Nutrient stoichiometry Wastewater treatment Ecosystem functioning Water quality management

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Cofactor engineering in cyanobacteria to overcome imbalance between NADPH and NADH: A mini review

Jongmoon Park,Yunnam Choi

《化学科学与工程前沿（英文）》 2017年第11卷第1期页码 66-71 doi: 10.1007/s11705-016-1591-1

摘要： Cyanobacteria can produce useful renewable fuels and high-value chemicals using sunlight and atmospheric carbon dioxide by photosynthesis. Genetic manipulation has increased the variety of chemicals that cyanobacteria can produce. However, their uniquely abundant NADPH-pool, in other words insufficient supply of NADH, tends to limit their production yields in case of utilizing NADH-dependent enzyme, which is quite common in heterotrophic microbes. To overcome this cofactor imbalance and enhance cyanobacterial fuel and chemical production, various approaches for cofactor engineering have been employed. In this review, we focus on three approaches: (1) utilization of NADPH-dependent enzymes, (2) increasing NADH production, and (3) changing cofactor specificity of NADH-dependent enzymes from NADH to NADPH.

关键词： NADH-dependent enzyme NADPH-dependent enzyme transhydrogenase site-directed mutagenesis enzyme engineering

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ECOLOGICAL EFFECTS OF NITROGEN DEPOSITION ON URBAN FORESTS: AN OVERVIEW

《农业科学与工程前沿（英文）》 2022年第9卷第3期页码 445-456 doi: 10.15302/J-FASE-2021429

摘要：

● Patterns and effects of N deposition on urban forests are reviewed.

关键词： biodiversity carbon sequestration nitrogen deposition nutrient imbalance soil acidification urban forest

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OFDM直接变频接收机中通用的I/Q不平衡估计与补偿方法 None

Fang-lin GU, Shan WANG, Wen-wu WANG

《信息与电子工程前沿（英文）》 2018年第19卷第3期页码 388-397 doi: 10.1631/FITEE.1700003

摘要：直接变频接收机由于具有低功耗的特点，受到广泛关注，但是它存在较严重的同相/正交（I/Q）分量不平衡问题：I/Q不平衡会恶化接收信号的信噪比，进而影响系统的传输容量和能够支持的调制方式。本文首先分析了I/Q不平衡对OFDM接收机接收信号的影响，在此基础上，定义了一个统计量用于刻画OFDM系统的I/Q不平衡特性，并提出一种实现I/Q不平衡参数估计与补偿的方法。特别地，进一步证明该统计量不受传输信道影响，因而该方法适用于高斯白噪声和多径衰落信道等不同场景。仿真结果表明，该方法可以实现对OFDM系统I/Q不平衡的准确估计与补偿，使补偿后系统的误比特率性能接近于不存在I/Q不平衡的情形。更重要的是，由于该方法不依赖于导频信号，因而可以应用于采用不同标准的OFDM系统。

关键词：同相/正交分量不平衡；正交频分复用；标准独立

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bioaccumulations based on a global data set and the implications for aquatic systems with aggravating nutrient imbalance

《环境科学与工程前沿（英文）》 2022年第16卷第3期 doi: 10.1007/s11783-021-1471-x

摘要：

• Hg bioaccumulation by phytoplankton varies among aquatic ecosystems.

关键词： Plankton Hg bioaccumulation Physiological characteristics A cross-system analysis Nutrient compositions Global data set

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Wavelet design for extracting weak fault feature based on lifting scheme

JIANG Hong-kai, WANG Zhong-sheng, HE Zheng-jia

《机械工程前沿（英文）》 2006年第1卷第2期页码 199-203 doi: 10.1007/s11465-006-0009-z

摘要： Weak fault features of mechanical signals are usually immersed in noisy signals. A new wavelet method based on lifting scheme to match weak fault characteristics is proposed. In this method, an initial set of finite biorthogonal filters is modified by a lifting and dual lifting procedure alternately, and different lifting operators and dual lifting operators are obtained. The properties of the initial wavelet is improved, and the new wavelet with particular properties is designed. Simulation and engineering results confirm that the proposed method is better than other wavelet methods for extracting weak fault feature. Modulus maxima of the detail signal in every operation cycle are extracted, the position and time that weak signal singularity occurs are clearly found, and slight rub-impact fault caused by axis misalignment and rotor imbalance of a heavy oil catalytic cracking set are desirably extracted. extracted.

关键词： misalignment imbalance particular position mechanical