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Properties of the satisfiability threshold of the strictly d-regular random(3,2s)-SAT problem

Frontiers of Computer Science 2020年第6期14卷 71-84页

作者： yongping wang Daoyun XU College of Computer Science and Technology Guizhou UniversityGuiyang 550025China College of Mathematics and Statistics Guizhou University of Finance and EconomicsGuiyang 550025China

A k-CNF(conjunctive normal form)formula is a regular(k,s)-CNF one if every variable occurs s times in the formula,where k≥2 and s>0 are ***(3,s)-CNF formulas have some good structural properties,so carry-ing out a probability analysis of the structure for random formulas of this type is easier than conducting such an analysisfor random 3-CNF *** subclasses of the regular(3,s)-CNF formula have also characteristics of intractabilitythat differ from random 3-CNF *** this purpose,we propose strictly d-regular(k,2s)-CNF formula,which is aregular(k,2s)-CNF formula for which d≥0 is an even num-ber and each literal occurs s-d/2 or s+d/2 times(the literals from a variable x are x and-x,where x is positive and-x isnegative).In this paper,we present a new model to generatestrictly d-regular random(k,2s)-CNF formulas,and focuson the strictly d-regular random(3,2s)-CNF *** F be a strictly d-regular random(3,2s)-CNF formula suchthat 2s>*** show that there exists a real number so suchthat the formula F is unsatisfiable with high probability whens>so,and present a numerical solution for the real *** result is supported by simulated experiments,and isconsistent with the existing conclusion for the case of d=***,we have a conjecture:for a given d,the strictlyd-regular random(3,2s)-SAT problem has an SAT-UNSAT(satisfiable-unsatisfiable)phase *** experimentssupport this ***,our experiments also showthat the parameter d is correlated with the intractability of the 3-SAT ***,our research maybe helpful for generating random hard instances of the 3-CNF formula.

关键词： satisfiability problem SAT-UNSAT phase transition generating random hard instances

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First observation results of Macao Science Satellite-1 on lightning-induced electron precipitation

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Science China Earth Sciences 2025年第1期 1-10页

作者： yongping wang Yixin SUN Qiugang ZONG Gaopeng LU Xudong GU Ze-Jun HU Bin LI Key Laboratory for Polar Science Ministry of Natural Resources Polar Research Institute of China Institute of Space Physics and Applied Technology Peking University State Key Laboratory of Lunar and Planetary Science Macau University of Science and Technology School of Earth and Space Sciences University of Science and Technology of China School of Electronic Information Wuhan University

The Medium-energy Electron Spectrometers(MES) is a space-borne instrument onboard Macao Science Satellite-1(MSS-1) dedicated to monitoring the typical charged particle radiation characteristics in the satellite orbit and the process of their occurrence and development, including short bursts of lightning-induced electron precipitation(LEP).This paper presents the first results of the LEP measurements by the MSS-1.47 LEP events are identified with the routine operation for 3 months since satellite launch, all within the range of 1.5

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On the upper bounds of (1,0)-super solutions for the regular balanced random (k,2s)-SAT problem

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Frontiers of Computer Science 2024年第4期18卷 139-146页

作者： yongping wang Daoyun XU Jincheng ZHOU School of Information Guizhou University of Finance and EconomicsGuiyang 550025China College of Computer Science and Technology Guizhou UniversityGuiyang 550025China School of Computer and Information Qiannan Normal University for NationalitiesDuyun 558000China Key Laboratory of Complex Systems and Intelligent Optimization of Guizhou Province Duyun 558000China

This paper explores the conditions which make a regular balancedrandom(k,2s)-CNFformula(1,O)-unsatisfiable with high *** conditions also make a random instance of the regular balanced(k-1,2(k-1)s)-SAT problem unsatisfiable with high probability,where the instance obeys a distribution which differs from the distribution obeyed by a regular balanced random(k-1,2(k-1)s)-CNF *** F be a regular balanced random(k,2s)-CNF formula where k≥3,then there exists a number so such that F is(1,O)-unsatisfiable with high probability if s>so.A numerical solution of the number so when k e(5,6,...,14)is given to conduct simulated *** simulated experiments verify the theoretical ***,the experiments also suggest that F is(1,O)-satisfiable with high probability if s is less than a certain value.

关键词： regular balanced random(k,2s)-SAT problem (1,0)-super solution upper bound

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Phytoplankton community from Lake Taihu,China,has dissimilar responses to inorganic and organic nutrients

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Journal of Environmental Sciences 2010年第10期22卷 1491-1499页

作者： Xiaodong wang Boqiang Qin Guang Gao yongping wang Xiangming Tang Timothy Otten State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008 China. Graduate School of the Chinese Academy of Sciences Beijing 100039 China Department of Environmental Sciences and Engineering University of North Carolina Chapel Hill NC 27517 USA

To evaluate the response of phytoplankton from Lake Taihu to different types of nutrients, the phytoplankton responses were measured after adding inorganic nitrogen （N） and phosphorus （P） or decomposed algal scum （Microcystis spp.） into the lake water. Both types of nutrients promoted an increase in phytoplankton biomass as determined by chlorophyll a and algal wet weight. The addition of decomposed algal scum resulted in a significantly greater phytoplankton response than the addition of inorganic N and P alone. The dissolved inorganic N and P in the inorganic nutrient treatment were found not limit phytoplankton growth. The higher algal biomass obtained in the treatment with decomposed algal scum indicated the importance of other organic nutrients besides N and P such as trace elements, as well as the importance of the form of N since the levels of ammonia nitrogen （NH4^＋-N） from the decomposed algal treatment were actually higher than that of the inorganic N and P addition. Microcystis spp. （Cyanobacteria）, Scenedesmus spp. （Chlorophyta） and Synechocystis spp. （Cyanobacteria） were the dominant taxa in the control, inorganic N and P treatment, and the decomposed algal scum treatment, respectively. Microcystis never bloomed in response to both types of nutrient additions indicating that the bloom propagation is not solely related to nutrient additions, but may be related to the absence of selective grazing from zooplankton.

关键词： phytoplankton inorganic nutrients decomposed algal scum

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Analysis and prognosis of tropical cyclone genesis over the western North Pacific on the background of global warming

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Acta Oceanologica Sinica 2007年第1期26卷 23-34页

作者： LI yongping wang Xiaofeng YU Runling QIN Zenghao Open Laboratory for Typhoon Research Shanghai Typhoon Institute China Meteorological Administration Shanghai 200030

As revealed by the observational study, there are more tropical cyclones generated over the western North Pacific from the early 1950s to the early 1970s in the 20th century and less tropical cyclones from the mid-1970s to the present. The decadal change of ＂tropical cyclones activities are closely related to the decadal changes of atmospheric general circulation in the troposphere, which provide favorable or unfavorable conditions for the formation of tropical cyclone. Furthermore, based on the simulation of corresponding atmospheric general circulation from a coupled climate model under the schemes of Intergovemmental Panel on Climate Change （IPCC）,special report on emission scenarios （SRES） A2 and B2 emissions scenarios an outlook on the tropical cyclone frequency generated over the western North Pacific in the coming half century is presented. It is indicated that in response to the global climate change the general circulation of atmosphere would become unfavorable for the formation of tropical cyclone as a whole and the frequency of tropical cyclones formation would likely decrease by 5% within the next half century, although more tropical cyclones would appear during a short period in it.

关键词： IPCC SRES A2 and B2 general circulation anomaly frequency of tropical cyclone

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Vertical diversity of sediment bacterial communities in two different trophic states of the eutrophic Lake Taihu, China

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Journal of Environmental Sciences 2013年第6期25卷 1186-1194页

作者： Keqiang Shao Guang Gao yongping wang Xiangming Tang Boqiang Qin State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of Sciences Nanjing Institute of Hydraulic Research

Vertical diversity of sediment bacterial communities in 2 different trophic states （macrophyte-dominated and algae-dominated） of the large shallow eutrophic Lake Taihu, China, were investigated using denaturing gradient gel electropfioresis （DGGE） and 16S rRNA sequence analysis. Clustering analysis of DGGE profiles showed that different clusters were recognized in different depths of sediment cores in the 2 lake trophic states. Analyses of the bacterial diversity, as estimated by the Shannon index （H＇）, showed that different sediment layers of the macrophyte-dominated state had higher diversity than the algae-dominated state. In addition, bacterial diversity of the sediment in the macrophyte-dominated state changed abruptly throughout the layers, but bacterial diversity of the algae-dominated state decreased gradually with sediment depth. Phylogenetic analysis showed that Proteobacteria was the most abundant phylum in the middle sediment of the 2 lake trophic states. In the macrophyte-dominated state, clone sequences related to Betaproteobacteria （50.0%） were the most abundant, followed by Epsilonproteobacteria （21.1%）, Acidobacteria （7.9%）, Deltaproteobacteria （7.9%）, Chloroflexi （7.9%）, and Bacteroidetes （5.3%）; whereas in the algae-dominated state, sequences affiliated with Betaproteobacteria （84.4%） were predominant, followed by Deltaproteobacteria （12.5%） and Acidobacteria （3.1%）. Canonical correspondence analysis showed that organic matter and pH play key roles in driving the vertical changes of bacterial community composition.

关键词： bacterial diversity canonical correspondence analysis (CCA) denaturing gradient gel electrophoresis (DGGE) sedimentcore macrophyte- and algae-dominated states 16S rRNA

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Influences of Sintering Process of Sprayed Precursors on the Struc-ture and Electrochemical Properties of LiMn_2O_4 Cathode Material

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Journal of Materials Science & Technology 2008年第2期24卷 211-214页

作者： Hui HUANG Chen wang Lei ZHANG yongping GAN Wenkui ZHANG College of Chemical Engineering and Materials Science Zhejiang University of Technology Hangzhou 310032 China

Well-defined spinel LiMn2O4 powders were synthesized via sintering a precursor, which was prepared by spraydrying method. The effects of sintering process on the structure and electrochemical properties of LiMn2O4 were discussed. It was found that a single sintering could not synthesize a pure LiMn2O4 compound, while two-step sintering procedure consisting of decomposing sprayed precursors at 350℃ and further sintering at an elevated temperature leads to the formation of a single-phased LiMn2O4 with homogeneous particle size distribution. As compared to that sintered in air, the two-step sintered LiMn2O4 in oxygen shows tighter structure and more uniform particle size, as well as better electrochemical properties. It delivers an initial discharge capacity of 131 mAh·g^-1 （1/10C）, and still has excellent cycling stability at higher rate （1/5C）.

关键词： Spinel LiMn2O4 Spray-drying method Li-ion batteries Sintering

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Selective Adsorption of Ag(I) from Electronic Waste Leachate Using Modified Silk Sericin

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Journal of Renewable Materials 2018年第1期6卷 102-116页

作者： Sijing Zhang Fengjiao Ao yongping wang Junxue Zhao Yongliang Ji Shuangli Chen School of Science Xi’an University of Architecture and Technology13 Yanta RoadXi’an710055China Shaanxi Provincial Academy of Environmental Science 49 North Changan RoadXi’an710061China School of Metallurgy Engineering Xi’an University of Architecture and Technology13 Yanta RoadXi’an710055China

A novel biosorbent was synthesized by grafting bisthiourea(BTU)on a silk sericin(SS)*** biosorbent was denoted as BTU-SS and characterized by Fourier transform infrared spectroscopy(FTIR),zeta potential measurements,elemental analysis,and X-ray photoelectron spectroscopy(XPS).As revealed by the adsorption experiments,both BTU-SS and SS showed low affinity towards coexisting base metallic ions in Ag(I)-Cu(II)-Zn(II)-Ni(II)-Pb(II)electronic waste leachate mixtures,while their adsorption capacities towards Ag(I)reached 30.5 and 10.4 mg∙g-1 at a pH of 5.0,***-SS showed higher selectivity towards Ag(I)than SS,as revealed by the Ag(I)partition coefficients between the biosorbents and the leachate(16634.6 and 403.3,respectively).As further demonstrated by column experiments,BTU-SS allowed the separation of Ag(I)from an electronic waste *** studies showed that the adsorption of Ag(I)was exothermic and spontaneous,while adsorption kinetic experiments revealed that chemisorption dominated the adsorption process with activation energies of 47.67 and 53.27 kJ∙mol-1 for BTU-SS and SS,*** and XPS analyses of fresh and Ag(I)-loaded BTU-SS further revealed an adsorption mechanism mainly involving electrostatic and coordination interactions.

关键词： Electronic waste leachate modified silk sericin selective adsorption silver recovery

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A wide-band low phase noise LC-tuned VCO with constant K_(VCO)/ω_(osc) for LTE PLL

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Journal of Semiconductors 2012年第2期33卷 106-110页

作者： Huang Jiwei wang Zhigong Li Kuili Li Zhengping wang yongping College of Physics and Information Engineering Fuzhou UniversityFuzhou 350002China Institute of RF&OE-IC Southeast UniversityNanjing 210096China Guangzhou Runxin Information Technology Ltd.Co. Guangzhou 510663China

A wideband LC-tuned voltage-controlled oscillator（LC-VCO） applied in LTE PLL frequency synthesizers with constant AVco/ωosc is *** order to minimize the loop bandwidth variations of PLL,a varactor array is proposed,which consists of a series of differential variable capacitor pairs and a series of single-pole double-throw（SPDT） switches to connect Vtune or *** switches are controlled by switching *** this scheme,the ratio of KV =（？）Cvar/（？）Vtune and the capacitance value of the capacitor array maintains relatively constant; furthermore,the loop bandwidth of the PLL fluctuation is *** 3.2—4.6-GHz VCO for multi-band LTE PLL is fabricated in a 0.13-μm RF-CMOS *** VCO exhibits a maximum variation of AVCO/ωosc of only±4%.The VCO also exhibits a low phase-noise of-124 dBc/Hz at a 1-MHz offset frequency and a low current consumption of 18.0 mA with a 1.2-V power supply.

关键词： voltage-controlled oscillator loop bandwidth LTE Kvco low phase noise

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Freeze-thaw processes of active-layer soils in the Nanweng'he River National Natural Reserve in the Da Xing'anling Mountains,northern Northeast China

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Research in Cold and Arid Regions 2018年第2期10卷 104-113页

作者： RuiXia He HuiJun Jin XiaoLi Chang yongping wang LiZhong wang State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu 730000China School of Civil Engineering Harbin Institute of TechnologyHarbinHeilongjiang 150090China Hunan University of Science and Technology XiangtanHunan 411201China School of Civil Engineering North University of NationalitiesYinchuanNingxia 750030China Nenjiangyuan Forest Ecosystem Research Station Institute of Agriculture and ForestryDa Xing'anling Forestry GroupJiagedaqiHeilongjiang 165000China

The active-layer soils overlying the permafrost are the most thermodynamically active zone of rock or soil and play important roles in the earth-atmosphere energy system. The processes of thawing and freezing and their associated complex hydrothermal coupling can significantly affect variation in mean annual temperatures and the formation of ground ice in permafrost regions. Using soil-temperature and-moisture data obtained from the active layer between September 2011 and October 2014 in the permafrost region of the Nanweng'he River in the Da Xing'anling Mountains, the freeze-thaw characteristics of the permafrost were studied. Based on analysis of ground-temperature variation and hydrothermal transport characteristics, the thawing and freezing processes of the active layer were divided into three stages:(1) autumn-winter freezing,(2) winter freeze-up, and(3) spring-summer thawing. Variations in the soil temperature and moisture were analyzed during each stage of the freeze-thaw process, and the effects of the soil moisture and ground vegetation on the freeze-thaw are discussed in this paper. The study's results show that thawing in the active layer was unidirectional, while the ground freezing was bidirectional(upward from the bottom of the active layer and downward from the ground surface).During the annual freeze-thaw cycle, the migration of soil moisture had different characteristics at different stages. In general, during a freezing-thawing cycle, the soil-water molecules migrate downward, i.e., soil moisture transports from the entire active layer to the upper limit of the permafrost. In the meantime, freeze-thaw in the active layer can be significantly affected by the soil-moisture content and vegetation.

关键词： Nanweng'he River National Natural Reserve active layer freeze-thawing processes moisture content vegetation effect

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