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All-fiber-based ultrastable laser with long-term frequency stability of 1.1×10^(-14) 被引量:4
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作者 黄亚峰 胡笛 +8 位作者 叶美凤 王亚婷 李彦黎 李明 陈胤男 屈求智 汪凌珂 刘亮 李唐 《Chinese Optics Letters》 SCIE EI CAS CSCD 2023年第3期84-89,共6页
We demonstrate an ultrastable miniaturized transportable laser system at 1550 nm by locking it to an optical fiber delay line[FDL].To achieve optimized long-term frequency stability,the FDL was placed into a vacuum ch... We demonstrate an ultrastable miniaturized transportable laser system at 1550 nm by locking it to an optical fiber delay line[FDL].To achieve optimized long-term frequency stability,the FDL was placed into a vacuum chamber with a five-layer thermal shield,and a delicate two-stage active temperature stabilization,an optical power stabilization,and an RF power stabilization were applied in the system.A fractional frequency stability of better than 3.2×10^[-15]at 1 s averaging time and1.1×10^[-14]at 1000 s averaging time was achieved,which is the best long-term frequency stability of an all-fiber-based ultrastable laser observed to date. 展开更多
关键词 fiber delay line frequency stability ultrastable laser
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A CMOS Fully Integrated Frequency Synthesizer with Stability Compensation 被引量:1
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作者 何捷 唐长文 +1 位作者 闵昊 洪志良 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2005年第8期1524-1531,共8页
A complete closed-loop third order s-domain model is analyzed for a frequency synthesizer. Based on the model and root-locus technique, the procedure for parameters design is described, and the relationship between th... A complete closed-loop third order s-domain model is analyzed for a frequency synthesizer. Based on the model and root-locus technique, the procedure for parameters design is described, and the relationship between the process,voltage,and temperature variation of parameters and the loop stability is quantitatively analyzed. A variation margin is proposed for stability compensation. Furthermore,a simple adjustable current cell in the charge pump is proposed for additional stability compensation and a novel VCO with linear gain is adopted to limit the total variation. A fully integrated frequency synthesizer from 1 to 1.05GHz with 250kHz channel resolution is implemented to verify the methods. 展开更多
关键词 frequency synthesizer closed-loop third-order s-domain loop parameters PVT variation stability variation margin
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Improving the operational stability of perovskite solar cells with cesium-doped graphene oxide interlayer
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作者 Masaud Almalki Katerina Anagnostou +15 位作者 Konstantinos Rogdakis Felix T.Eickemeyer Mostafa Othman Minas M.Stylianakis Dimitris Tsikritzis Anwar Q.Alanazi Nikolaos Tzoganakis Lukas Pfeifer Rita Therisod Xiaoliang Mo Christian M.Wolff Aïcha Hessler-Wyser Shaik M.Zakeeruddin Hong Zhang Emmanuel Kymakis Michael Grätzel 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第9期483-490,共8页
Perovskite solar cells(PSCs)have made great advances in terms of power conversion efficiency(PCE),yet their subpar stability continues to hinder their commercialization.The interface between the perovskite layer and t... Perovskite solar cells(PSCs)have made great advances in terms of power conversion efficiency(PCE),yet their subpar stability continues to hinder their commercialization.The interface between the perovskite layer and the charge-carrier transporting layers plays a crucial role in undermining the stability of PSCs.In this work,we propose a strategy to stabilize high-performance PSCs with PCE over 23%by introducing a cesium-doped graphene oxide(GO-Cs)as an interlayer between the perovskite and hole-transporting material.The GO-Cs treated PSCs exhibit excellent operational stability with a projected T80(the time where the device PCE reduces to 80%of its initial value)of 2143 h of operation at the maximum powering point under one sun illumination. 展开更多
关键词 Perovskite solar cells Doped graphene oxide Graphene related material long-term operational stability
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Retrospective Case Series on The Enduring Rotational Stability of The AcrySof IQ Toric Intraocular Lens in Cataract Patients Suffering from Myopia
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作者 Jie Luo Yang Liu +2 位作者 Bing Wang Lei Li Junyu Yang 《Journal of Clinical and Nursing Research》 2024年第3期207-214,共8页
Objective:To analyze the enduring rotational steadiness of AcrySof IQ Toric intraocular lens(IOL)in cataract patients suffering from myopia in a long-term study.Methods:A retrospective study was conducted on a case se... Objective:To analyze the enduring rotational steadiness of AcrySof IQ Toric intraocular lens(IOL)in cataract patients suffering from myopia in a long-term study.Methods:A retrospective study was conducted on a case series involving 78 patients.A total of 120 eyes with an axial length(AL)ranging from 24-30 mm and corneal astigmatism≥1.50 D underwent implantation of AcrySof IQ Toric IOL guided by the version navigation system.The eyes were divided into two groups based on AL.Group A included 60 eyes with high myopia(AL≥26 mm),while Group B consisted of eyes with low to moderate myopia(24 mm≤AL<26 mm).Data on the preoperative AL were collected.Measurements were taken for residual astigmatism,the best corrected visual acuity(BCDVA),corneal astigmatism,and IOL rotation occurring between 24-and 48-months post-surgery.The percentage of eyes with an IOL rotation of under 5°and 10°was analyzed.Results:The mean length of follow-up times was recorded as 34.27±4.98,and the average rotation was 2.73±1.29°.Group A exhibited a slightly higher average rotation of 2.87±1.31°,compared to the rotation of 2.59±1.27°observed in Group B.At both the 24-36 month and 26-48 month post-operation marks,the degree of IOL rotation did not show a statistically significant difference between the two groups,with none of the patients experiencing a rotation exceeding 10°(P>0.05).The percentage of rotation degrees under 5°was recorded as 98.22%.After the procedure,the BCDVA was 0.1322±0.03 LogMAR.There was a substantial increase in theχvalue after the operation as compared to the pre-operativeχ^(2) value(χ^(2)=76.79).The standard deviation of preoperative corneal astigmatism was statistically significant(P<0.05)at 2.17±1.08 D.Following the surgical procedure,the remaining astigmatism was measured at 0.41±0.26 D.The data showed a notable gap in statistical significance(t=4.281,P<0.05).Conclusion:The AcrySof Toric IOL was a reliable solution for managing corneal astigmatism in cataract patients with myopia,demonstrating excellent long-term rotational stability. 展开更多
关键词 ASTIGMATISM long-term MYOPIA Rotational stability
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Identification of Stability Domains for Flow Parameters in Fused Filament Fabrication Using Acoustic Emission
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作者 Zhen Li Lei Fu +2 位作者 Xinfeng Zou Baoshan Huang Fengshou Gu 《Journal of Dynamics, Monitoring and Diagnostics》 2024年第3期225-235,共11页
In Fused Filament Fabrication(FFF),the state of material flow significantly influences printing outcomes.However,online monitoring of these micro-physical processes within the extruder remains challenging.The flow sta... In Fused Filament Fabrication(FFF),the state of material flow significantly influences printing outcomes.However,online monitoring of these micro-physical processes within the extruder remains challenging.The flow state is affected by multiple parameters,with temperature and volumetric flow rate(VFR)being the most critical.The study explores the stable extrusion of flow with a highly sensitive acoustic emission(AE)sensor so that AE signals generated by the friction in the annular region can reflect the flow state more effectively.Nevertheless,the large volume and broad frequency range of the data present processing challenges.This study proposes a method that initially selects short impact signals and then uses the Fast Kurtogram(FK)to identify the frequency with the highest kurtosis for signal filtration.The results indicate that this approach significantly enhances processing speed and improves feature extraction capabilities.By correlating AE characteristics under various parameters with the quality of extruded raster beads,AE can monitor the real-time state of material flow.This study offers a concise and efficient method for monitoring the state of raster beads and demonstrates the potential of online monitoring of the flow states. 展开更多
关键词 acoustic emission center frequency fast kurtogram fused filament fabrication stability domains
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Application of an amphipathic molecule at the NiO_(x)/perovskite interface for improving the efficiency and long-term stability of the inverted perovskite solar cells
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作者 Guibin Shen Hongye Dong +4 位作者 Fan Yang Xin Ren Ng Xin Li Fen Lin Cheng Mu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第3期454-462,I0013,共10页
The presence of defects and detrimental reactions at NiO_(x)/perovskite interface extremely limit the efficiency performance and long-term stability of the perovskite solar cells(PSCs) based on NiO_(x).Herein,an amphi... The presence of defects and detrimental reactions at NiO_(x)/perovskite interface extremely limit the efficiency performance and long-term stability of the perovskite solar cells(PSCs) based on NiO_(x).Herein,an amphipathic molecule Triton X100(Triton) is modified on the NiO_(x)surface.The hydrophilic chain of Triton as a Lewis base additive can coordinate with the Ni3+on the NiO_(x)surface which can passivate the interfacial defects and hinder the detrimental reactions at the NiO_(x)/perovskite interface.Additionally,the hydrophobic chain of Triton protrudes from the NiO_(x)surface to prevent moisture from penetrating into the NiO_(x)/perovskite interface.Consequently,the NiO_(x)/Triton-based devices(MAPbI3as absorbing layer) show superior moisture and thermal stability,retaining 88.4% and 64.3% of the initial power conversion efficiency after storage in air(40%-50% relative humidity(RH)) at 25 ℃ for 1070 h and in N2at 85℃ for 800 h,respectively.Moreover,the efficiency increases from 17.59% to 19.89% because of the passivation defect and enhanced hole-extraction capability.Besides,the NiO_(x)/Triton-based PSCs with Cs_(0.05)(MA_(0.15)FA_(0.85))_(0.95)Pb(I_(0.85)Br_(0.15))3perovskite as the light-absorbing layer also exhibits better moisture and thermal stability compared to the control devices,indicating the viability of our strategies.Of particular note,a champion PCE of 22.35% and 20.46% was achieved for small-area(0.1 cm^(2)) and large-area(1.2 cm^(2)) NiO_(x)/Triton-based devices,respectively. 展开更多
关键词 Perovskite solar cells NiO_(x) Defect passivation long-term stability Amphipathic molecule
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Non-Fullerene-Based Inverted Organic Photovoltaic Device with Long-Term Stability
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作者 Do Hui Kim Febrian T.A.Wibowo +4 位作者 Dongchan Lee Narra V.Krishna Sujung Park Shinuk Cho Sung-Yeon Jang 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2023年第3期214-221,共8页
In this work,we developed the PM6:Y6-based inverted structure organic photovoltaic(i-OPV)with improved power conversion efficiency(PCE)and long-term stability by resolving the origins of the performance deterioration.... In this work,we developed the PM6:Y6-based inverted structure organic photovoltaic(i-OPV)with improved power conversion efficiency(PCE)and long-term stability by resolving the origins of the performance deterioration.The deep defects between the metal oxide-based electron transport layer and bulk-heterojunction photoactive layer interface were responsible for suboptimal PCE and facilitated degradation of devices.While the density of deep traps is increased during the storage of i-OPV,the penetrative oxygen-containing defects additionally generated shallow traps below the band-edge of Y6,causing an additional loss in the open-circuit voltage.The suppression of interfacial defects by chemical modification effectively improved the PCE and long-term stability of i-OPV.The modified i-OPV(mi-OPV)achieved a PCE of 17.42%,which is the highest value among the reported PM6:Y6-based i-OPV devices.Moreover,long-term stability was significantly improved:~90%and~80%retention of its initial PCE after 1200 h of air storage and illumination,respectively. 展开更多
关键词 deep trap inverted structure long-term stability organic photovoltaic power conversion efficiency
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Could Long-Term Stability Last Forever?
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作者 Maria K. Koleva 《Journal of Modern Physics》 CAS 2023年第4期450-460,共11页
The subject of the present paper is to prove that the recently introduced conjecture of boundedness puts a ban over the view of stability as asymptotic property. This result comes in sharp contrast with the prescripti... The subject of the present paper is to prove that the recently introduced conjecture of boundedness puts a ban over the view of stability as asymptotic property. This result comes in sharp contrast with the prescription of the traditional thermodynamics and statistical physics which consider the existence of equilibrium as asymptotic property of all systems. The difference commences from the use of infinitesimal calculus as the basic implement for modelling by the latter while the primary premise of the conjecture of boundedness is sustaining the energy/matter/information permanently bounded and finite. The latter property overrules the infinitesimal calculus as the major implement of modelling because, among all, it is proven that the traditional one suffers unsoluble difficulties. 展开更多
关键词 long-term stability Equilibrium Infinitesimal Calculus BOUNDEDNESS Decomposition Theorem Certain Information Universal Mechanism for Collapse
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A long-term frequency-stabilized erbium-fiber-laser-based optical frequency comb with an intra-cavity electro-optic modulator 被引量:6
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作者 张颜艳 闫露露 +6 位作者 赵文宇 孟森 樊松涛 张龙 郭文阁 张首刚 姜海峰 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第6期366-370,共5页
We demonstrate an optical frequency comb based on an erbium-doped-fiber femtosecond laser with the nonlinear polarization evolution scheme. The repetition rate of the laser is about 209 MHz. By controlling an intra-ca... We demonstrate an optical frequency comb based on an erbium-doped-fiber femtosecond laser with the nonlinear polarization evolution scheme. The repetition rate of the laser is about 209 MHz. By controlling an intra-cavity electro- optic modulator and a piezo-transducer, the repetition rate can be stabilized with a high-bandwidth servo in a frequency range of 3 kHz, enabling long-term repetition rate phase-locking. The in-loop frequency stability of repetition rate is about 1.6× 10-13 in an integration time of 1 s, limited by the measurement system; and it is inversely proportional to integration time in the short term. Furthermore, using a common path f-2f interferometer, the carrier envelope offset frequency of the comb is obtained with a signal-to-noise ratio of 40 dB in a 3-MHz resolution bandwidth. Stabilized cartier envelope offset frequency exhibits a deviation of 0.6 mHz in an integration time of 1 s. 展开更多
关键词 optical frequency comb fiber laser frequency stabilization frequency instability
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Frequency domain stability criteria for fractional-order control systems 被引量:5
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作者 汪纪锋 《Journal of Chongqing University》 CAS 2006年第1期30-35,共6页
This paper concerns about the frequency domain stability criteria for fractional-order control systems. On the base of characteristics of the fractional-order equations solutions, we consider the Nyquist stability cri... This paper concerns about the frequency domain stability criteria for fractional-order control systems. On the base of characteristics of the fractional-order equations solutions, we consider the Nyquist stability criterion in a wider sense and obtain a more common means to analyze the stability of fractional-order systems conveniently. Finally, this paper illustrates the generalized stability criteria with an example to show the effect of the parameters variation on the fractional-order control systems. 展开更多
关键词 FRACTIONAL-ORDER control system frequency analysis stability criterion
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Tuning method for governor control parameters of hydropower generator in isolated grid considering primary frequency performance and small-signal stability 被引量:1
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作者 Zhenhua Xu 《Global Energy Interconnection》 2018年第5期568-575,共8页
This paper presents a method of tuning governor control parameters of an isolated hydropower generator considering the primary frequency performance and small-signal stability. First, generators that can be operated i... This paper presents a method of tuning governor control parameters of an isolated hydropower generator considering the primary frequency performance and small-signal stability. First, generators that can be operated in isolated state are identified. Second, different schemes are proposed for generator mode switching from on-grid to off-grid state through comparison and mechanism analysis. Third, the time domain model and frequency domain model of the isolated generator governor are constructed to respectively estimate the primary frequency performance and small signal stability. Parameter sets that satisfy the primary frequency performance and small signal stability are acquired as optimal values of governor control parameters. Finally, the measurement-based parameters of the governor are identified and validated using simulations to demonstrate the feasibility and effectiveness of the method. 展开更多
关键词 Isolated grid PRIMARY frequency regulation capability Small-signal stability LAPLACE transfer Parameter ADJUSTING
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Dynamic Stability Analysis of Caisson Breakwater in Lifetime Considering the Annual Frequency of Severe Storm
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作者 王禹迟 王元战 洪宁宁 《China Ocean Engineering》 SCIE EI CSCD 2015年第2期287-300,共14页
In the dynamic stability analysis of a caisson breakwater, most of current studies pay attention to the motion characteristics of caisson breakwaters under a single periodical breaking wave excitation. And in the life... In the dynamic stability analysis of a caisson breakwater, most of current studies pay attention to the motion characteristics of caisson breakwaters under a single periodical breaking wave excitation. And in the lifetime stability analysis of caisson breakwater, it is assumed that the caisson breakwater suffers storm wave excitation once annually in the design lifetime. However, the number of annual severe storm occurrence is a random variable. In this paper, a series of random waves are generated by the Wen Sheng-chang wave spectrum, and the histories of successive and long-term random wave forces are built up by using the improved Goda wave force model. It is assumed that the number of annual severe storm occurrence is in the Poisson distribution over the 50-year design lifetime, and the history of random wave excitation is generated for each storm by the wave spectrum. The response histories of the caisson breakwater to the random waves over 50-year design lifetime are calculated and taken as a set of samples. On the basis of the Monte Carlo simulation technique, a large number of samples can be obtained, and the probability assessment of the safety of the breakwater during the complete design lifetime is obtained by statistical analysis of a large number of samples. Finally, the procedure of probability assessment of the breakwater safety is illustrated by an example. 展开更多
关键词 caisson breakwater dynamic stability lifetime wave spectrum annual storm frequency
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Modelling and Simulation of Performance of the Microgrid Frequency Stability Control during Unplanned Islanding: The Case Study of Mwenga Hydropower
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作者 Eligard Kyaruzi Francis Arthur M. Omari John P. John 《Smart Grid and Renewable Energy》 CAS 2022年第7期160-171,共12页
A grid connected microgrid connects to the grid at a point of common coupling. Due to the great inertia of the grid which accelerates and decelerates the generator when its frequency tends to deviate, the grid connect... A grid connected microgrid connects to the grid at a point of common coupling. Due to the great inertia of the grid which accelerates and decelerates the generator when its frequency tends to deviate, the grid connected microgrid operates at a frequency of the infinity bus. Frequency instability is one of the major challenges facing the grid connected microgrid during islanding. The power demand variation causes the variation in rotor speed, resulting to frequency deviation. Frequency can be brought back to standard by varying the power generation to match with the varying load. The performance of the frequency stability control system at Mwenga hydroelectric microgrid has been studied. Through site visitation, the power demand and generation status data were collected and analysed for model preparation. The results of the study indicate that, during islanding, the Mwenga rural electrification project is observed to be subjected to power imbalance which leads to frequency instability. Although the frequency control system tries to keep the system at a nominal frequency by maintaining the continuous balance between generation and varying load demand, however the system still operates with large magnitude of overshoot, undershoot and longer settling time. 展开更多
关键词 MODELLING frequency stability Unplanned Islanding Mwenga
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Enhancing the stability of planar perovskite solar cells by green and inexpensive cellulose acetate butyrate 被引量:1
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作者 Bo Xiao Yongxin Qian +5 位作者 Xin Li Yang Tao Zijun Yi Qinghui Jiang Yubo Luo Junyou Yang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第1期259-265,I0007,共8页
Although the efficiency of organic–inorganic hybrid halide perovskite solar cells has been improved rapidly, the intrinsic instability of perovskite materials restricts their commercial application. Here, an eco-frie... Although the efficiency of organic–inorganic hybrid halide perovskite solar cells has been improved rapidly, the intrinsic instability of perovskite materials restricts their commercial application. Here, an eco-friendly and low-cost organic polymer, cellulose acetate butyrate(CAB), was introduced to the grain boundaries and surfaces of perovskite, resulting in a high-quality and low-defect perovskite film with a nearly tenfold improvement in carrier lifetime. More importantly, the CAB-treated perovskite films have a well-matched energy level with the charge transport layers, thus suppressing carrier nonradiative recombination and carrier accumulation. As a result, the optimized CAB-based device achieved a champion efficiency of 21.5% compared to the control device(18.2%). Since the ester group in CAB bonds with Pb in perovskite, and the H and O in the hydroxyl group bond with the I and organic cations in perovskite,respectively, it will contribute to superior stability under heat, high humidity, and light soaking conditions. After aging under 35% humidity(relative humidity, RH) for 3300 h, the optimized device can still maintain more than 90% of the initial efficiency;it can also retain more than 90% of the initial efficiency after aging at 65 ℃, 65% RH, or light(AM 1.5G) for 500 h. This simple optimization strategy for perovskite stability could facilitate the commercial application of perovskite solar cells. 展开更多
关键词 Planar perovskite solar cells long-term stability Organic polymer Well-matched energy level Charge transportation and extraction
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Wheat Grain Yield and Yield Stability in a Long-Term Fertilization Experiment on the Loess Plateau 被引量:28
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作者 HAO Ming-De FAN Jun +3 位作者 WANG Quan-Jiu DANG Ting-Hui GUO Sheng-Li WANG Ji-Jun 《Pedosphere》 SCIE CAS CSCD 2007年第2期257-264,共8页
To provide a scientific basis for sustainable land management, a 20-year fertility experiment was conducted in Changwu County, Shaanxi Province, China to investigate the effects of long-term application of chemical fe... To provide a scientific basis for sustainable land management, a 20-year fertility experiment was conducted in Changwu County, Shaanxi Province, China to investigate the effects of long-term application of chemical fertilizers on wheat grain yield and yield stability on the Loess Plateau using regression and stability analysis. The experiment consisted of 17 fertilizer treatments, containing the combinations of different N and P levels, with three replications arranged in a randomized complete block design. Nitrogen fertilizer was applied as urea, and P was applied as calcium superphosphate. Fertilizer rates had a large effect on the response of wheat yield to fertilization. Phosphorus, combined with N, increased yield significantly (P 〈 0.01). In the unfertilized control and the N or P sole application treatments, wheat yield had a declining trend although it was not statistically significant. Stability analysis combined with the trend analysis indicated that integrated use of fertilizer N and P was better than their sole application in increasing and sustaining the productivity of rainfed winter wheat. 展开更多
关键词 dryland wheat yield long-term fertilization nitrogen PHOSPHORUS yield stability
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Long-term inorganic plus organic fertilization increases yield and yield stability of winter wheat 被引量:6
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作者 Huan Chen Aixing Deng +6 位作者 Weijian Zhang Wei Li Yuqiang Qiao Taiming Yang Chengyan Zheng Chengfu Cao Fu Chen 《The Crop Journal》 SCIE CAS CSCD 2018年第6期589-599,共11页
An understanding of wheat yield and yield stability response to fertilization is important for sustainable wheat production. A 36-year long-term fertilization experiment was employed to evaluate the yield and yield st... An understanding of wheat yield and yield stability response to fertilization is important for sustainable wheat production. A 36-year long-term fertilization experiment was employed to evaluate the yield and yield stability of winter wheat. Five fertilization regimes were compared,including(1) CK, no fertilizer;(2) NPK, inorganic fertilizer only;(3) O, organic fertilizer only;(4)NPKO, 50% of NPK plus 50% of O, and(5) HNPKO, 80% of NPK plus 80% of O. The greatest yield increase was recorded in HNPKO, followed by NPKO, with O producing the lowest mean yield increase. Over the 36 years, the rate of wheat yield increase in fertilized plots ranged from95.31 kg ha-1 year-1 in the HNPKO to 138.65 kg ha-1 year-1 in the O. Yield stability analysis using the additive main effects and multiplicative interactions(AMMI) method assigned 62.3%, 26.3%,and 11.4% of sums of squares to fertilization effect, environmental effect, and fertilization ×environment interaction effect, respectively. The combination of inorganic and organic fertilization(NPKO and HNPKO) appeared to produce more stable yields than O or NPK, with lower coefficients of variation and AMMI stability value. However, wheat grown with O seemed to be the most susceptible to climate change and the least productive among the fertilized plots.Significant correlations of grain yield with soil properties and with mean air temperature were observed. These findings suggest that inorganic + organic fertilizer can increase wheat yield and its stability by improvement in soil fertility and reduction in variability to climate change. 展开更多
关键词 Winter wheat Grain YIELD YIELD stability AMMI analysis long-term FERTILIZATION
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Frequency stabilization of a 399-nm laser by modulation transfer spectroscopy in an ytterbium hollow cathode lamp 被引量:3
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作者 王文丽 叶捷 +3 位作者 蒋海灵 毕志毅 马龙生 徐信业 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第1期310-315,共6页
The modulation transfer spectroscopy in an ytterbium hollow cathode lamp at 399 nm is measured. The error signal for frequency locking is optimized by measuring the dependences of its slope, linewidth and magnitude on... The modulation transfer spectroscopy in an ytterbium hollow cathode lamp at 399 nm is measured. The error signal for frequency locking is optimized by measuring the dependences of its slope, linewidth and magnitude on various parameters. Under the optimum condition, the laser frequency at 399 nm can be stabilized. The long-term stability of laser frequency is measured by monitoring the fluorescence signal of the ytterbium atomic beam induced by the locked laser. The laser frequency is shown to be tightly locked, and the stabilized laser is successfully applied to the cooling of ytterbium atoms. 展开更多
关键词 laser frequency stabilization modulation transfer spectroscopy YTTERBIUM hollow cathode lamp
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Arbitrary frequency stabilization of a diode laser based on visual Labview PID VI and sound card output 被引量:2
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作者 冯国胜 武寄洲 +5 位作者 王晓锋 郑宁宣 李玉清 马杰 肖连团 贾锁堂 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第10期248-251,共4页
We report a robust method of directly stabilizing a grating feedback diode laser to an arbitrary frequency in a large range. The error signal, induced from the difference between the frequency measured by a wavelength... We report a robust method of directly stabilizing a grating feedback diode laser to an arbitrary frequency in a large range. The error signal, induced from the difference between the frequency measured by a wavelength meter and the preset target frequency, is fed back to the piezoelectric transducer module of the diode laser via a sound card in the computer. A visual Labview procedure is developed to realize a feedback system. In our experiment the frequency drift of the diode laser is reduced to 8 MHz within 25 min. The robust scheme can be adapted to realize the arbitrary frequency stabilization for many other kinds of lasers. 展开更多
关键词 frequency stabilization Labview PID VI diode laser target frequency
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Long-term straw incorporation increases rice yield stability under high fertilization level conditions in the rice–wheat system 被引量:4
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作者 Jianwei Zhang Weiwei Li +4 位作者 Yan Zhou Yanfeng Ding Lei Xu Yu Jiang Ganghua Li 《The Crop Journal》 SCIE CSCD 2021年第5期1191-1197,共7页
Straw incorporation is a global common practice to improve soil fertility and rice yield.However,the effect of straw incorporation on rice yield stability is still unknown,especially under high fertilization level con... Straw incorporation is a global common practice to improve soil fertility and rice yield.However,the effect of straw incorporation on rice yield stability is still unknown,especially under high fertilization level conditions.Here,we reported the effect of straw returning on rice yield and yield stability under high fertilization levels in the rice–wheat system over nine years.The results showed that straw incorporation did not significantly affect the average rice yield of nine years.Straw incorporation reduced the coefficient of variation of rice yield by 25.8%and increased the sustainable yield index by 8.2%.The rice yield positively correlated with mean photosynthetically active radiation (PAR) of rice growth season and the effects of straw incorporation on rice yield depended on the PAR.Straw incorporation increased the rice yield by 5.4%in the low PAR years,whereas it did not affect the rice yield in the high PAR years.Long-term straw incorporation lowered soil bulk density but improved the soil organic matter,total N,available N,available P,and available K more strongly than straw removal.Our findings suggest that straw incorporation can increase rice yield stability through improving the resistance of rice plant growth to low PAR. 展开更多
关键词 long-term straw incorporation Rice yield stability Rice-wheat system PAR
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Dimensionality regulation in tin halide perovskite solar cells: Toward high performance and stability
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作者 Huanhuan Yao Shurong Wang +2 位作者 Zhiwen Jin Liming Ding Feng Hao 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第2期144-156,I0005,共14页
Tin halide perovskites(THPs)have received extensive attention due to their low toxicity and excellent optoelectronic properties,and are considered to be the most promising alternatives to develop efficient lead-free p... Tin halide perovskites(THPs)have received extensive attention due to their low toxicity and excellent optoelectronic properties,and are considered to be the most promising alternatives to develop efficient lead-free perovskite solar cells.However,due to the unique and inherent characteristics of Sn^(2+)being easily oxidized to Sn^(4+)and fast crystallization,tin perovskite solar cells(TPSCs)show relatively poor performance and stability,compared to the lead counterparts.Recently,the introduction of bulky organic spacers into three-dimensional(3D)THPs for dimensional regulation can not only prevent the intrusion of water and oxygen,but also inhibit the self-doping effect and ion migration.In this review,we will detail how dimensional regulation enables TPSCs with high performance and superior stability.First,we summarize the intrinsic properties of THPs and analyze the root causes of their poor performance and instability.Next,we discuss the specific structure and types of the dimensional regulation strategy.Then,the mechanism of dimensional regulation is discussed in detail,mainly from inhibiting the Sn^(2+)oxidation,optimizing crystallization,passivating defects,and improving energy level alignment.Finally,future challenges and prospects for dimensional regulation are elaborated to help researchers develop more efficient and stable TPSCs. 展开更多
关键词 Organic spacers Dimensional regulation long-term stability Performance Photovoltaics
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