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Deriving the slope-mean shielded astronomical solar radiation spectrum and slope-mean possible sunshine duration spectrum over the Loess Plateau

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Journal of Mountain Science 2020年第1期17卷 133-146页

作者： chen nan Key Laboratory of Spatial Data Mining & Information Sharing Ministry of Education Fuzhou University Spatial Information Research Center of Fujian Province Fuzhou University

Solar radiation is often shielded by terrain relief, especially in mountainous areas, before reaching the surface of the Earth. The objective of this paper is to study the spatial structures of the shielded astronomical solar radiation(SASR) and the possible sunshine duration(PSD) over the Loess Plateau. To this end, we chose six test areas representing different landforms over the Loess Plateau and the software package of Matlab was used as the main computing platform. In each test area, 5-m-resolution digital elevation model established from 1:10,000 scale topographic maps was used to compute the corresponding slope, SASR and PSD. Then, we defined the concepts of the slope-mean SASR spectrum and the slope-mean PSD spectrum, and proposed a method to extract them from the computed slope, SASR and PSD over rectangular analysis windows. Using this method, we found both spectrums in a year or in a season for each of the four seasons in the six test areas. Each spectrum was found only when the area of the corresponding rectangular analysis window was greater than the corresponding stable area of the spectrum. The values of the two spectrums decreased when the slope ***, the values of the stable areas of the spectrums in a year or in a season were positively correlated with the variable coefficients of the slope or the profile curvature. The values of the stable areas of the two spectrums in a year or in a season may represent the minimum value of test areas for corresponding future research on the spatial structures of the SASR or PSD. All the findings herein suggest that the spatial structures of the PSD and the SASR are caused by the interactions between solar radiation and terrain relief and that the method for extracting either spectrum is effective for detecting their spatial structures. This study may deepen our understanding of the spatial structure of solar radiation and help us further explore the distribution of solar energy in mountainous re

关键词： Digital elevation model Shielded extraterrestrial solar radiation Spectrum Possible Sunshine duration Slope Loess Plateau

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Scale problem:Influence of grid spacing of digital elevation model on computed slope and shielded extra-terrestrial solar radiation

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Frontiers of Earth Science 2020年第1期14卷 171-187页

作者： nan chen Key Laboratory of Spatial Data Mining&Information Sharing(Ministry of Education) Fuzhou UniversityFuzhou 350108 China Spatial Information Research Center of Fujian Province Fuzhou UniversityFuzhou 350108 China

Solar radiation is the primary energy source that drives many of Earth’s physical and biological processes and determines the patterns of climate and productivity on the surface of the Earth.A fundamental proportion of solar radiation is composed of shielded extraterrestrial solar radiation(SESR),which can be computed using the slope and aspect derived from a digital elevation model(DEM).The objective of this paper is to determine the influence of the grid spacing of the DEM(the influence of the scale of the DEM)on the errors of slope,aspect and *** paper puts forward the concepts of slope representation error,aspect representation error,and SESR representation error and then studies the relations among these errors and the grid spacing of *** find that when the grid spacing of a DEM becomes coarser,the average SESR increases;the increase in SESR is dominated by the grid cells of the DEM with a negative slope representation error,whereas SESR generally decreases in the grid cells with a positive slope representation *** the grid spacing varies,the distribution of the percentages of positive SESR representation errors on the slope,which is classified into 11 slope intervals,is independent of the grid spacing;this distribution is concentrated across some slope ***,the average absolute value and mean square error of the SESR representation error are closely related to those of the slope representation error and the aspect representation *** findings in this study may be useful for predicting and reducing the errors in SESR measurements and may help to avoid mistakes in foture research and in practical applications in which SESR is the data of interest or plays a vital role in an analysis.

关键词： scale problem digital elevation model grid spacing slope shielded extra-terrestrial solar radiation

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On fractional control method for four-wheel-steering vehicle

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Science China(Technological Sciences) 2009年第3期52卷 603-609页

作者： chen Ning chen nan chen YanDong College of Mechanical Engineering Southeast UniversityNanjing 210096China College of Mechanical and Electronic Engineering Nanjing Forestry UniversityNanjing 210037China

Four-wheel-steering (4WS) system can enhance vehicle cornering ability by steering the rear wheels in accordance with the front wheels steering and vehicle status. With such steering control system, it becomes possible to improve the lateral stability and handling performance. In this paper, a new control method for 4WS vehicle is proposed, its rear wheels steering angle is in accordance with the angle of front wheels steering and vehicle yaw rate, and the effects of front wheels steering angle velocity are considered by adopting the fractional derivative theory. Some design specifications for control law are also given. The effects of the control method are verified by a kind of numerical scheme presented in this paper. The dynamic characteristics such as the side-slip angle and the yaw angle velocity of the vehicle gravity center are compared among three kinds of vehicles with different control methods. And the kinematics characteristics such as turning radius between 4WS and 2WS are also discussed. Nu- merical simulation shows that the control method presented can improve the transient response and reduce the turning radius of 4WS vehicle.

关键词： fractional derivative four-wheel-steering computation simulation chassis control system

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Photoinduced Weyl semimetal phase and anomalous Hall effect in a three-dimensional topological insulator

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Chinese Physics B 2021年第11期30卷 94-101页

作者： Meng-nan chen Wen-Chao chen School of Science Hangzhou Dianzi UniversityHangzhou 310018China Institute of Advanced Magnetic Materials College of Materials and Environmental EngineeringHangzhou Dianzi UniversityHangzhou 310018China

Motivated by the fact that Weyl fermions can emerge in a three-dimensional topological insulator on breaking either time-reversal or inversion symmetries,we propose that a topological quantum phase transition to a Weyl semimetal phase occurs under the off-resonant circularly polarized light,in a three-dimensional topological insulator,when the intensity of the incident light exceeds a critical *** circularly polarized light effectively generates a Zeeman exchange field and a renormalized Dirac mass,which are highly *** phase transition can be exactly characterized by the first Chern number.A tunable anomalous Hall conductivity emerges,which is fully determined by the location of the Weyl nodes in momentum space,even in the doping *** predictions are experimentally realizable through pump-probe angle-resolved photoemission spectroscopy and raise a new way for realizing Weyl semimetals and quantum anomalous Hall effects.

关键词： Floquet theory Weyl semimetal topological phase transition Hall conductivity

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THE ROLE OF HYDROGEN-BONDING INTERACTION IN POLY(VINYL ALCOHOL)/POLY(ACRYLIC ACID) BLENDING SOLUTIONS AND THEIR FILMS

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Chinese Journal of Polymer Science 2010年第6期28卷 903-911页

作者： nan-xi chen Jun-hua Zhang State Key Laboratory of Polymer Materials Engineering of China Sichuan UniversityChengdu 610065China

The aim of this work is to investigate the hydrogen-bonding interaction in poly(vinyl alcohol)(PVA)/poly(acrylic acid)(PAA) blending system and its influence on rheological properties in solution and the physical properties in solid state. Introducing PAA into PVA solutions resulted in a thickening behavior of blend *** viscosity of the solutions increased with PAA content increasing,and a maximum viscosity could be obtained when the ratio of PVA/PAA was 70/30. The intermolecular hydrogen-bonding and miscibility between PVA and PAA in solid state were investigated by differential scanning calorimetry(DSC),Fourier transform infrared spectroscopy(FTIR) and mechanical *** results displayed the great influence of introducing PAA on the properties of blending *** tensile strength increased from 89.31 MPa to 119.8 MPa and Young’s modulus improved by over 300%with increasing PAA concentration compared with those of pure PVA *** systematically studying the rheological behaviors of solutions and the physical properties of films,the influence of hydrogen-bonding in solutions and solid states were discussed.

关键词： Polymer blending Rheology Hydrogen-bonding Molecular network Miscibility

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Growth and Photoluminescence Properties of Tetrapod-Shaped ZnO Microcrystals-Whiskers and Microrods

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Journal of Materials Science & Technology 2009年第3期25卷 427-432页

作者： Xiaojun Liang Bingfa Liu nan chen Laboratory for Basic Physics Nanchang University Jiangxi 330031 China School of Materials Science and Engineering Nanchang University Jiangxi 330031 China

Tetrapod-shaped ZnO microcrystals in forms of whiskers and microrods have been grown in the same crucible by thermal evaporation of Zn/C mixtures at a temperature of 930℃ in air without using any catalyst. The tetrapod-shaped ZnO microrods were capped by hexagonal pyramids. It is for the first time observed that the tetrapod-shaped ZnO whiskers and microrods have quite different morphologies, and this is believed to be a result of different growth behaviors associated with these two forms of ZnO microcrystals. The octa-twin model has been used to discuss their growth behaviors. Photoluminescence properties of these two forms of tetrapod-shaped ZnO microcrystals have been investigated using different excitation wavelengths. Both of the two forms of ZnO microcrystals showed strong green emission and weak ultraviolet emission behaviors. The excitation spectrum of the tetrapod-shaped ZnO whiskers showed a strong excitation peak at 395 nm, which was not observed for the tetrapod-shaped ZnO microrods.

关键词： ZnO Tetrapod-shaped whiskers Tetrapod-shaped mirorods Growth behaviors

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OPTIMAL AND INCENTIVE COMPATIBLE PRICING FOR HETEROGENEOUS PERIODS

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Journal of Systems Science and Systems Engineering 2008年第1期17卷 50-65页

作者： Jian chen nan ZHANG Shuo HUANG Research Center for Contemporary Management Key Research Institute of Humanities and Social Sciences at Universities School of Economics and Management Tsinghua University Beijing 100084 China

This paper studies a service firm whose business time can be divided into several periods, each providing different value to customers. Heterogeneous service is a major reason resulting in imbalances between supply and demand. Since customers differ in their degree of impatience, firrns can use differential pricing mechanisms to optimize their objectives and match supply with demand in each period, by inducing customers to choose different periods. We study two types of firrns, an internal firm, the objective of which is to maximize the system＇s （including the f＇nan and all the customers） total net value, and a commercial firm, which aims to optimize its own profit. Though impatience factors are customers＇ private information, for each type of firm, we derive the optimal incentive compatible pricing policy, under which all the coming customers will follow the firm＇s assignment, that is, patient customers will buy the service in high-value periods, but their waiting time will be longer, while impatient customers will enter into the low-value periods, but they will be compensated by shorter waiting times. Furthermore, in the internal firm, we also prove that this mechanism enables the decentralization of decisions, while maintaining centralized system-wide optimality. Numerical analysis shows that when there is sufficient capacity, the internal firm does not always need to set lower prices than the commercial firm in every period.

关键词： Delay cost queuing differential pricing information asymmetry incentive compatibility

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Observations of nitrous acid and its relative humidity dependence in Shanghai

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Journal of Environmental Sciences 2006年第5期18卷 910-915页

作者： HAO nan ZHOU Bin chen Dan chen Li-min Department of Environmental Science and Engineering Fudan University Shanghai 200433 China

Nitrous acid, HNO2, is an important precursor of OH radicals in the troposphere. Measurements of HNO2 and NO2, using differential optical absorption spectroscopy （DOAS）, were performed in Shanghai, China for a period from October 22, 2004 to January 4, 2005. The mean （and median） hourly concentrations of HNO2 and NO2 during this period were 1.1 （0.7） ppb and 24 （21.4） ppb respectively. A correlation between HNO2/NO2 and PM10 mass concentrations was obtained. This correlation suggests that significant heterogeneous chemical production of HNO2 may occur through NO2 reactions on aerosol surfaces. This hypothesis was further supported by detailed analysis of selected pollution episodes in this study. At the same time, the water dependence of HNO2 formation was studied by analysis of relative humidity （RH）. It showed that the maximum HNO2/NO2 ratio was increased along with RH below 70% and inhibited at RH〉70%.

关键词： DOAS heterogeneous formation nitrous acid PM,o aerosol relative humidity

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Challenges and Recent Developments of Photoflow-Reversible Deactivation Radical Polymerization(RDRP)

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Chinese Journal of Polymer Science 2021年第9期39卷 1069-1083页

作者： Zhuo-Ran Zhong Yi-nan chen Yang Zhou Mao chen State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular ScienceFudan UniversityShanghai 200433China

Photo-controlled reversible-deactivation radical polymerizati on(photo-RDRP)has been investigated as a"green"and spatiotem-porally controlling pathway for polymer *** the combination of photo-RDRP and flow chemistry has offered opportunities to increase light intensity and enable uniform light irradiation,problems associated with flow approaches still remain for photoflow-RDRP,which has hindered merging flow polymerization with other cutting-edge ***,we summarize challenges and recent achievements in photoflow-RDRP including the development of(a)droplet/slug-flow to regulate reside nee time distribution,(b)mixing techniques to tailor polymer,(c)polymerization in duced self-assembly,and(d)computer-aided *** hope this work will provide in formative knowledge to people in related fields and stimulate novel ideas to promote polymer synthesis in both academia and industry.

关键词： Controlled radical polymerization RDRP Photopolymerization Flow chemistry Flow polymerization

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Realgar-indigo naturalis formula for the treatment of patients with relapsed and arsenic trioxide-resistant acute promyelocytic leukemia:A case series

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Journal of Integrative Medicine 2024年第5期22卷 614-620页

作者： Yong-guang Fang Shi-lin Huang nan-nan chen Department of Hematology PLA 967th HospitalDalian 116021Liaoning ProvinceChina

Introduction There is currently no standard treatment for relapsed and arsenic trioxide(ATO)-resistant acute promyelocytic leukemia(APL).Here,we report a case series of realgar-indigo naturalis formula(RIF)for the successful treatment of patients with relapsed and ATO-resistant *** presentation Two patients in the first relapse and one in the second relapse failed to achieve hematologic complete remission(HCR)when reinduced by ATO;the other five patients progressed to relapse during ATO-based regimens for post-remission *** eight patients received RIF in three doses per day totaling 130 mg/kg(≤30 pills)as induction therapy and achieved HCR at a median time of 46.5 *** received 5 years of post-remission therapy,which consisted of combined chemotherapy followed by *** this period,the patients did not experience renal dysfunction or QT interval *** the last follow-up,three patients survived without relapse,two patients survived with a second or third relapse and third or fourth remission,and the other three patients relapsed for a third or fourth time and *** 5-year overall survival and event-free survival rates were 75.0%(95%confidence interval[CI]:31.5–93.1)and 37.5%(95%CI:5.6–71.7),*** RIF for induction therapy and RIF combined with chemotherapy for post-remission therapy may represent an effective and safe protocol for the treatment of patients with relapsed and ATO-resistant APL.

关键词： Acute promyelocytic leukemia Realgar-indigo naturalis formula Arsenic Trioxide Resistant Case report

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