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Leaf area increases with species richness in young experimental stands of subtropical trees

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Journal of Plant Ecology 2017年第1期10卷 128-135页

作者： siyi Peng Bernhard Schmid Josephine Haase Pascal A.Niklaus Institute of Evolutionary Biology and Environmental Studies University of ZürichWinterthurerstrasse 190CH-8057 ZürichSwitzerland

Aims Most biodiversity-ecosystem functioning research has been carried out in grassland ecosystems,and little is known about whether forest ecosystems,in particular outside the temperate zone,respond ***,we tested whether productivity,assessed as leaf area index(LAI),increases with species richness in young experimental stands of subtropical trees,whether this response is similar for early-season leaf area(which is dominated by evergreens)and seasonal leaf area increase(which is dominated by deciduous species),and whether responses saturate at high species *** We used a planted tree biodiversity experiment in south-east China to test our *** was determined three times by digital hemispheric photography in 144 plots that had been planted with 400 trees each,forming communities with 1,2,4,8 or 16 tree *** Findings LAI increased significantly with tree species richness in the fifth year of stand ***,but weaker,statistically non-significant trends were observed 1 year *** did not observe leaf area overyielding and the presence of particularly productive and unproductive species explained large amounts of variation in leaf area,suggesting that selection-type effects contributed substantially to the biodiversity effects we found in this early phase of stand *** sizes were moderate to large and comparable in magnitude to the ones reported for grassland ***(and tropical)forests harbor substantial parts of global net primary production and are critical for the Earth’s carbon and hydrological cycle,and our results suggest that tree diversity critically supports these ecosystem services.

关键词： BEF-China digital hemispheric photography field biodiversity experiment overyielding subtropical forest

Cetus: an efficient symmetric searchable encryption against file-injection attack with SGX

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Science China(Information Sciences) 2021年第8期64卷 195-212页

作者： Yanyu HUANG siyi LV Zheli LIU Xiangfu SONG Jin LI Yali YUAN Changyu Dong College of Cyber Science and the College of Computer Science Tianjin Key Laboratory of Network and Data Security TechnologyNankai University School of Computer Science and Technology Shandong University School of Computer Science Guangzhou University Department of Computer Science University of G?ttingen School of Computing Newcastle University

Symmetric searchable encryption(SSE) allows the users to store and query their private data in the encrypted database. Many SSE schemes for different scenarios have been proposed in the past few years, however, most of these schemes still face more or fewer security issues. Using these security leakages,many attacks against the SSE scheme have been proposed, and especially the non-adaptive file injection attack is the most serious. Non-adaptive file injection attack(NAFA) can effectively recover some extremely important private information such as keyword plaintext. As of now, there is no scheme that can effectively defend against such attacks. We first propose the new security attribute called toward privacy to resist nonadaptive file injection attacks. We then present an efficient SSE construction called Cetus to achieve toward privacy. By setting up a buffer and designing the efficient oblivious reading algorithm based on software guard extensions(SGX), we propose the efficient one-time oblivious writing mechanism. Oblivious writing protects the update pattern and allows search operations to be performed directly on the data. The experiment results show that Cetus achieves O(aw) search time and O(1) update communication. The practical search time, communication, and computation overheads incurred by Cetus are lower than those of state-of-the-art.

关键词： searchable encryption SGX technique file injection attack forward/toward privacy cloud databases

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Rayleigh–Taylor instability of viscoelastic self-rewetting film flowing down a temperature-controlled inclined substrate

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Chinese Physics B 2023年第6期32卷 352-367页

作者：安思亦菅永军 School of Mathematical Science Inner Mongolia UniversityHohhot 010021China

Rayleigh–Taylor(RT) instability of gravity-driven viscoelastic self-rewetting film flowing under an inclined substrate uniformly heated or cooled is considered. The surface tension of self-rewetting film is considered as a quadratic function of temperature. The long wave hypothesis is used to derive a nonlinear free surface evolution equation of the thin viscoelastic film. Linear stability analysis shows that for a prescribed the viscoelastic coefficient, substrate cooling products instability,while substrate heating remains stability. Furthermore, we analyze the influence of viscoelastic coefficient on RT instability. Results show that the viscoelastic coefficient reinforces the RT instability whether the substrate is heated or ***, we use the line method to numerically simulate the nonlinear evolution equation and systematically examine the space-time variation of the film free surface. The numerical results illustrate that increasing the viscoelastic coefficient can enhance the disturbance amplitude and wave frequency. This means that the viscoelastic coefficient makes the system unstable, which is consistent with result of the linear stability analysis. In addition, the oscillation tends to accumulate downstream of the inclined substrate when the evolution time is long enough. Finally, the variation of film thickness with related parameters for different viscoelastic coefficients is investigated.

关键词： Rayleigh–Taylor instability self-rewetting film viscoelastic liquid

Cancer burden and trends in China:A review and comparison with Japan and South Korea

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Chinese Journal of Cancer Research 2020年第2期32卷 129-139页

作者： Dianqin Sun Maomao Cao He Li siyi He Wanqing Chen National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital Chinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100021China

Objective:To summarize the cancer burden and trends in China,compare the differences among China,Japan,and South Korea and discuss possible causes of the ***:Incidence and mortality data were extracted from the online cancer database including the GLOBOCAN 2018 and the Global Burden of Disease Study *** analysis was conducted using the joinpoint analysis,and annual percent changes were ***:Cancers resulted in approximately 62.9 million disability-adjusted life years(DALYs)in China in *** cancer had the greatest contribution,followed by liver cancer,stomach cancer,and esophageal *** trajectory of progress in the reduction of liver and stomach cancers was observed in ***,China still faced a heavy burden of lung cancer and a growing burden of cancers related to westernized lifestyle such as colorectal cancer,while Japan and South Korea have achieved reductions in colorectal cancer and lung cancer,***,China had a lower age-standardized cancer incidence rate but higher cancer mortality and DALY rates than Japan and South ***:China is in the cancer transition stage with a rising burden of colorectal,prostate,and breast cancers along with a heavy burden of lung and upper digestive tract *** into consideration the effectiveness of screening and tobacco control in Japan and South Korea,improvement in the current tobacco control policy and cancer screening systems may contribute to cancer control in China.

关键词： Cancer burden trend China comparison

Optimization of tensile strength for new type acetone-urea-formaldehyde furan resin using uniform design

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China Foundry 2011年第1期8卷 30-35页

作者： Lin Shengjun Zhao Wei Li Yuancai Tong siyi Wang Wenqing School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan 430074 Hubei China Guangxi Yuchai Machinery Company Limited Yulin 537005 Guangxi China

In this study,the 24 h tensile strength of new type acetone-urea-formaldehyde furan resin (nitrogen content 3%) was investigated by uniform design *** independent variables such as acetone:formaldehyde molar ratio (mol/mol),solution pH value,reaction temperature (℃) and reaction time (min) were considered in the experiments.U13(134) uniform design was employed and the equation of 24 h tensile strength model was obtained after 13 *** 24 h tensile strength was optimized by applying single factor experiments and stepwise non-linear regression *** (Minitab 15 trial version) and MATLAB (R2010a trial version) were used for data *** t-value and p-value indicate that the major impact factors include the interaction effect of solution pH value and reaction temperature (X2X3),the linear terms of acetone:formaldehyde molar ratio (X1),reaction time (X4) followed by the square effects of acetone/formaldehyde molar ratio (X1X1).The optimized results were achieved with the acetone:formaldehyde molar ratio (mol/mol) at 3:1,solution pH value at 6.0,reaction temperature at 70℃,and reaction time at 140 min,*** method can not only significantly reduce the number and cost of the tests,but also provide a good experimental design strategy for the development of furan *** investigation shows that the predicted results of 24 h tensile strength are consistent well with the experimental ones.

关键词： acetone-urea-formaldehyde furan resin 24 h tensile strength single factor experiment uniform design stepwise regression

Evaluating the Ozone Valley over the Tibetan Plateau in CMIP6 Models

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Advances in Atmospheric Sciences 2022年第7期39卷 1167-1183页

作者： Kequan ZHANG Jiakang DUAN siyi ZHAO Jiankai ZHANG James KEEBLE Hongwen LIU Key Laboratory for Semi-Arid Climate Change of the Ministry of Education College of Atmospheric SciencesLanzhou UniversityLanzhou 730000China Department of Chemistry University of CambridgeCambridge CB21EWUK National Centre for Atmospheric Science Cambridge CB21EWUK

Total column ozone(TCO)over the Tibetan Plateau(TP)is lower than that over other regions at the same latitude,particularly in *** feature is known as the“TP ozone valley”.This study evaluates long-term changes in TCO and the ozone valley over the TP from 1984 to 2100 using Coupled Model Intercomparison Project Phase 6(CMIP6).The TP ozone valley consists of two low centers,one is located in the upper troposphere and lower stratosphere(UTLS),and the other is in the middle and upper ***,the CMIP6 models simulate the low ozone center in the UTLS well and capture the spatial characteristics and seasonal cycle of the TP ozone valley,with spatial correlation coefficients between the modeled TCO and the Multi Sensor Reanalysis version 2(MSR2)TCO observations greater than 0.8 for all CMIP6 *** analysis reveals that models which use fully coupled and online stratospheric chemistry schemes simulate the anticorrelation between the 150 hPa geopotential height and zonal anomaly of TCO over the TP better than models without interactive chemistry *** suggests that coupled chemical-radiative-dynamical processes play a key role in the simulation of the TP ozone *** CMIP6 models underestimate the low center in the middle and upper stratosphere when compared with the Microwave Limb Sounder(MLS)***,the bias in the middle and upper stratospheric ozone simulations has a marginal effect on the simulation of the TP ozone *** CMIP6 models predict the TP ozone valley in summer will deepen in the future.

关键词： Tibetan Plateau stratospheric ozone ozone valley CMIP6

Optimization of Preparation of Fe_(3)O_(4)-L by Chemical Co-Precipitation and Its Adsorption of Heavy Metal Ions

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Journal of Renewable Materials 2023年第5期11卷 2209-2232页

作者： Junzhen Di Xueying Sun siyi Zhang Yanrong Dong Bofu Yuan College of Civil Engineering Liaoning Technical UniversityFuxin123000China

To address the serious pollution of heavy metals in AMD,the difficulty and the high cost of treatment,Fe_(3)O_(4)-L was prepared by the chemical co-precipitation *** on the single-factor and RSM,the effects of particle size,total Fe concentration,the molar ratio of Fe^(2+)to Fe^(3+)and water bath temperature on the removal of AMD by Fe_(3)O_(4)-L prepared by chemical co-precipitation method were *** adsorption experiments were conducted on Cu^(2+),Zn^(2+)and Pb^(2+)using Fe_(3)O_(4)-L prepared under optimal conditions as *** adsorption properties and mechanisms were analyzed by combining SEM-EDS,XRD and FTIR for *** study showed that the effects of particle size,total Fe concentration and the molar ratio of Fe^(2+)to Fe^(3+)are *** by response surface optimization analysis,the optimum conditions for the preparation of Fe_(3)O_(4)-L were a particle size of 250 mesh,a total Fe concentration of 0.5 mol/L,and a molar ratio of Fe^(2+)to Fe^(3+)of 1:*** these conditions,the removal rates of Cu^(2+),Zn^(2+),and Pb^(2+)were 94.52%,88.49%,and 96.69%*** adsorption of Cu^(2+),Zn^(2+)and Pb^(2+)by Fe_(3)O_(4)-L prepared under optimal conditions reached equilibrium at 180 min,with removal rates of 99.99%,85.27%,and 97.48%,*** adsorption reaction of Fe_(3)O_(4)-L for Cu^(2+)and Zn^(2+)is endothermic,while that for Pb^(2+)is ***_(3)O_(4)-L can still maintain a high adsorption capacity after five cycles of adsorption-desorption ***^(2+),Zn^(2+)and Pb^(2+)mainly exist as CuFe_(2)O_(4),Zn(OH)2,ZnFe_(2)O_(4)and PbS after being adsorbed by Fe_(3)O_(4)-L,which is the result of the combination of physical diffusion,ion exchange and surface complexation reaction.

关键词： Chemical co-precipitation Fe_(3)O_(4)-L single-factor experiment RSM adsorption characterization

Modeling and Optimization of a Fractionation,Absorption,and Stabilization System in an Industrial Fluid Catalytic Cracking Process

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China Petroleum Processing & Petrochemical Technology 2022年第3期24卷 117-127页

作者： Long Jian Jiang siyi Wang Wei Zhang Feng Han Jifei Fan Chen Key Laboratory of Smart Manufacturing in Energy Chemical Process Ministry of EducationEast China University of Science and TechnologyShanghai 200237China SINOPEC Jiujiang Company Jiujiang 332013China SINOPEC Research Institute of Petroleum Processing Beijing 100083China

Fluid catalytic cracking(FCC)is a vitally important refinery *** fractionation,absorption,and stabilization system in the FCC process is a significant way to obtain key products,and its parameters will directly affect the quality of the *** this work,using industrial data from an actual FCC process,a model of the FCC fractionation,absorption,and stabilization system was developed using process simulation *** sequence quadratic program algorithm was then used to identify the parameters of each tower,increasing the accuracy of the simulation ***,using this improved model,a sensitivity analysis was performed to examine the effects of different operating *** pattern-search method was then used to optimize the operating parameters of the *** results showed that the optimized model has good prediction accuracy,and using the model,it was found that changing the operation parameters could result in a 1.84%improvement in economic *** such,the developed model was demonstrated to be usefully applicable to the optimization of the process operation of an FCC fractionation,absorption,and stabilization system.

关键词： fluid catalytic cracking sequence quadratic program process modeling parameters identification patternsearch method

Functionalizable and Recyclable Aliphatic Polycarbonates Derived from Biomass Feedstocks and CO_(2)

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Chemical Research in Chinese Universities 2023年第5期39卷 809-815页

作者： WU Yanchen FAN Huazhong SHAN siyi WANG Siqi CAI Zhongzheng ZHU Jian-Bo National Engineering Laboratory of Eco-Friendly Polymeric Materials(Sichuan) College of ChemistrySichuan UniversityChengdu 610064P.R.China

Two bio-based seven-membered cyclic carbonate monomers M1 and M2 were synthesized in three steps from myrcene,which could produce polycarbonates via ring-opening polymerization using metal or organic *** functionalizable olefin moieties in resulting polycarbonates have driven post-polymerization modifications via radical cross-linking and hydrogenation,enabling the resulting polymers with tunable thermal *** importantly,the chemical recycling of P(M)s was achieved through"monomer→polymer⇄dimer",which presented a platform for the synthesis of chemically recyclable biobased polycarbonates.

关键词： Biomass CO_(2) Polycarbonate Functionalization Chemical recyclability