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Quantifying soil nitrous oxide emissions in spring freezing-thawing period over different vegetation types in Northeast China

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Journal of Mountain Science 2022年第7期19卷 1919-1930页

作者： WU Bin MU Chang-cheng LIU Hui xu ya-kun ZHANG Yue yaNG Jia-shuo xu Wen-nian Hubei Key Laboratory of Construction and Management in Hydropower Engineering China Three Gorges UniversityYichang443002China College of Hydraulic&Environmental Engineering China Three Gorges UniversityYichang443002China Ministry of Education Key Laboratory of Sustainable Forest Ecosystem Management Northeast Forestry UniversityHarbin150040China Survey Planning and Design Institute of DaxinganlingNational Forestry and Grassland AdministrationDaxinganling165100China Engineering Research Center of Eco-Environment in Three Gorges Reservoir Region Ministry of EducationChina Three Gorges UniversityYichang443002China State Key Laboratory of Forest and Soil Ecology Institute of Applied EcologyChinese Academy of SciencesShenyang110016China Hubei Key Laboratory of Disaster Prevention and Mitigation China Three Gorges UniversityYichang443002China Key Laboratory of Geological Hazards on Three Gorges Reservoir Area Ministry of EducationYichang443002China

Environmental changes significantly alter the structure,diversity and activity of soil microbial communities during spring freezing-thawing period,leading to changes in the soil microbial nitrogen *** in N_(2)O fluxes after land use conversion from primary forest to secondary forest,Korean pine plantation and cropland in northeast China have not been *** experiments were conducted to measure soil N_(2)O fluxes in a primary forest,two secondary forests,a Korean pine plantation,and one maize field in a temperate region in northeast China from 2017-03-06 to *** the experimental period,the soil was exclusively a nitrogen source for all land *** found that N_(2)O emissions ranged from 15.63 to 68.74μg m^(-2) h^(-1),and cumulative N_(2)O emissions ranged from 0.33 to 2.10 kg ha^(-1) during the *** N_(2)O emissions from the maize field were significantly higher than that from primary forest,Korean pine plantation,hardwood forest,and Betula platyphylla forest by 262.1% to 536.4%.Compared with other ecosystems in similar studies,the N_(2)O emission rates of all ecosystem types in this study were low during the spring thaw *** multiple linear regression indicated that there were significant correlations between N_(2)O emissions and environmental factors(air temperature and soil temperature,soil water content,soil p H,NH_(4)^(+)-N,NO_(3)^(-)-N,and soil organic carbon).The results showed that conversion of land use from primary forest to hardwood forest,Korean pine plantation or maize field greatly increased soil N_(2)O emissions during spring freezing-thawing period,and N_(2)O emissions from primary forest were almost the same as those from Betula platyphylla forest.

关键词： N_(2)O emission Land use change Environmental factors Nitrogen cycle

Two new steroidal glucosides from Ophiopogon japonicus (L.f.) Ker-Gawl

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Chinese Chemical Letters 2008年第7期19卷 825-828页

作者： ya Jiuan xu Tun Hai xu Ling Zhu Hao Hong Feng Zhao Sheng xu Xie Yun Shan Si Dong Han Dong Ming xu Academy of Traditional Chinese Medicine and Material Medica of Jilin Province Changchun 130021China School of Traditional Chinese Medicine Beijing University of Chinese Medicine Beijing 100102China School of Traditional Chinese Medicine Xinjiang University of Medicine Urumchi 830011 China

Two new steroidal glucosides, 26-O-β-D-glucopyranosyl （25S）-furost-5-ene-1β,3β,22α,26-tetraol l-O-β-D-xylopyranosyl- （1 → 3）-[α-h-rhamnopyranosyl-（1 → 2）]-[β-D-fueopyranoside and （25R） spirost-5-ene-3β,14α-diol-3-β-O-β-L-rhanmopyranosyl- （1 → 2）-[β-D-xylopyranosyl（1 → 4）]-[-β-D-glucopyranoside, were isolated from the Ophiopogon japonicus （L.f.） Ker-Gaw. Their structures were elucidated by spectroscopic methods.

关键词： Ophiopogon japonicus (L.f.) Ker-Gawl Steroidal glucosides Liliaceae

Experimental investigation of creep behavior of clastic rock in Xiangjiaba Hydropower Project

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Water Science and Engineering 2015年第1期8卷 55-62页

作者： Yu Zhang Wei-ya xu Jian-fu Shao Hai-bin Zhao Wei Wang College of Pipeline and Civil Engineering China University of Petroleum Geotechnical Research Institute Hohai University Hunan Provincial Key Laboratory of Key Technology on Hydropower Development

There are many fracture zones crossing the dam foundation of the Xiangjiaba Hydropower Project in southwestern China. Clastic rock is the main media of the fracture zone and has poor physical and mechanical properties. In order to investigate the creep behavior of clastic rock, triaxial creep tests were conducted using a rock servo-controlling rheological testing machine. The results show that the creep behavior of clastic rock is significant at a high level of deviatoric stress, and less time-dependent deformation occurs at high confining pressure. Based on the creep test results, the relationship between axial strain and time under different confining pressures was investigated, and the relationship between axial strain rate and deviatoric stress was also discussed. The strain rate increases rapidly, and the rock sample fails eventually under high deviatoric stress. Moreover, the creep failure mechanism under different confining pressures was analyzed. The main failure mechanism of clastic rock is plastic shear, accompanied by a significant compression and ductile dilatancy. On the other band, with the determined parameters, the Burgers creep model was used to fit the creep curves. The results indicate that the Burgers model can exactly describe the creep behavior of clastic rock in the Xiangjiaba Hydropower Project.

关键词： Rock mechanics Clastic rock Creep behavior Triaxial creep test Burgers creep model Xiangjiaba Hydropower Project

Reactive carbonyl compounds(RCCs) cause aggregation and dysfunction of fibrinogen

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Protein & Cell 2012年第8期3卷 627-640页

作者： ya-Jie xu Min Qiang Jin-Ling Zhang Ying Liu Rong-Qiao He State Key Laboratory of Brain and Cognitive Science Institute of BiophysicsChinese Academy of SciencesBeijing 100101China Graduate University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Mental Health Institute of PsychologyChinese Academy of SciencesBeijing 100101China

Fibrinogen is a key protein involved in coagulation and its deposition on blood vessel walls plays an important role in the pathology of *** the causes of fibrinogen(fibrin)deposition have been studied in depth,little is known about the relationship between fibrinogen deposition and reactive carbonyl compounds(RCCs),compounds which are produced and released into the blood and react with plasma protein especially under conditions of oxidative stress and ***,we investigated the effect of glycolaldehyde on the activity and deposition of fibrinogen compared with the common RCCs acrolein,methylglyoxal,glyoxal and *** the same concentration(1 mmol/L),glycolaldehyde and acrolein had a stronger suppressive effect on fibrinogen activation than the other three *** aggregated when it was respectively incubated with glycolaldehyde and the other RCCs,as demonstrated by SDS-PAGE,electron microscopy and intrinsic fluorescence intensity *** with Congo Red showed that glycolaldehyde-and acrolein-fibrinogen distinctly formed amyloid-like ***,the five RCCs,particularly glycolaldehyde and acrolein,delayed human plasma *** glycolaldehyde showed a markedly suppressive effect on fibrinogenesis,none did the other four RCCs when their physiological blood concentrations were employyed,*** together,it is glycolaldehyde that suppresses fibrinogenesis and induces protein aggregation most effectively,suggesting a putative pathological process for fibrinogen(fibrin)deposition in the blood.

关键词： fibrinogen acrolein glycolaldehyde glyoxal malondialdehyde methylglyoxal

Clinical value of precise rehabilitation nursing in management of cerebral infarction

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World Journal of Clinical Cases 2024年第1期12卷 24-31页

作者： ya-Na xu Xiu-Zhen Wang Xiao-Rong Zhang Department of Neurology Wuhan Fourth HospitalWuhan 430030Hubei ProvinceChina Department of Neurosurgery The First People's Hospital of Jiangxia DistrictWuhan City(Union Jiangnan Hospital of Huazhong University of Science and Technology)Wuhan 430200Hubei ProvinceChina

BACKGROUND Cerebral infarction,previously referred to as cerebral infarction or ischemic stroke,refers to the localized brain tissue experiencing ischemic necrosis or softening due to disorders in brain blood supply,ischemia,and *** precision rehabilitation nursing model for chronic disease management is a continuous,fixed,orderly,and efficient nursing model aimed at standardizing the clinical nursing process,reducing the wastage of medical resources,and improving the quality of medical *** To analyze the value of a precise rehabilitation nursing model for chronic disease management in patients with cerebral *** Patients(n=124)admitted to our hospital with cerebral infarction between November 2019 and November 2021 were enrolled as the study *** random number table method was used to divide them into a conventional nursing intervention group(n=61)and a model nursing intervention group(n=63).Changes in the nursing index for the two groups were compared after conventional nursing intervention and precise rehabilitation intervention nursing for chronic disease *** Compared with the conventional intervention group,the model intervention group had a shorter time to clinical symptom relief(P<0.05),lower Hamilton Anxiety Scale and Hamilton Depression Scale scores,a lower incidence of total complications(P<0.05),a higher disease knowledge mastery rate,higher safety and quality,and a higher overall nursing satisfaction rate(P<0.05).CONCLUSION The precision rehabilitation nursing model for chronic disease management improves the clinical symptoms of patients with cerebral infarction,reducing the incidence of total complications and improving the clinical outcome of patients,and is worthy of application in clinical practice.

关键词： Precise rehabilitation nursing model for chronic disease management Cerebral infarction Knowledge of disease Safety and quality

State-chain sequential feedback reinforcement learning for path planning of autonomous mobile robots

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Journal of Zhejiang University-Science C(Computers and Electronics) 2013年第3期14卷 167-178页

作者： Xin MA ya xu Guo-qiang SUN Li-xia DENG Yi-bin LI School of Control Science and Engineering Shandong University

This paper deals with a new approach based on Q-learning for solving the problem of mobile robot path planning in complex unknown static *** a computational approach to learning through interaction with the environment,reinforcement learning algorithms have been widely used for intelligent robot control,especially in the field of autonomous mobile ***,the learning process is slow and *** practical applications,rapid rates of convergence are *** at the problem of slow convergence and long learning time for Q-learning based mobile robot path planning,a state-chain sequential feedback Q-learning algorithm is proposed for quickly searching for the optimal path of mobile robots in complex unknown static *** state chain is built during the searching *** one action is chosen and the reward is received,the Q-values of the state-action pairs on the previously built state chain are sequentially updated with one-step *** the increasing number of Q-values updated after one action,the number of actual steps for convergence decreases and thus,the learning time decreases,where a step is a state *** simulations validate the efficiency of the newly proposed approach for mobile robot path planning in complex *** results show that the new approach has a high convergence speed and that the robot can find the collision-free optimal path in complex unknown static environments with much shorter time,compared with the one-step Q-learning algorithm and the Q(λ)-learning algorithm.

关键词： Path planning Q-learning Autonomous mobile robot Reinforcement learning

Partial Oxidation of Butane to Syngas over Nickel Supported Catalysts Modified by Alkali Metal Oxide and Rare-Earth Metal Oxide

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Chinese Chemical Letters 2001年第1期12卷 43-46页

作者： Sheng Lin LIU Long ya xu Su Juan XIE Qing Xia WANG Group 804 Dalian Institute of Chemical PhysicsCASP.O.Box 110Dalian 116023

The partial oxidation of butane (POB) to syngas over nickel supported catalysts was first investigated with a flow-reactor, TG and UVRRS. The NiO/gamma -Al2O3 is the most suitable for the POB among NiO/gamma -Al2O3, NiO/MgO and NiO/SiO2. And the reaction performance of the NiO/gamma -Al2O3 shows little difference from those of the nickel supported catalysts modified by alkali metal oxide and rare-earth metal oxide. However, modification with Li2O and La2O3 can suppress carbon-deposition of the NiO/gamma -Al2O3, which contains graphite-like species during the POB reaction.

关键词： Carbon-deposition Nickel supported catalysts Partial oxidation of butane Syngas

Effect of psychological nursing intervention on anxiety level and quality of life in patients with gastrointestinal peptic ulcer

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World Journal of Gastrointestinal Surgery 2024年第9期16卷 2953-2960页

作者： Xiao-Rong Zhang yan-Song Li ya-Na xu Department of Neurology Wuhan Fourth HospitalWuhan 430030Hubei ProvinceChina Department of Nursing Bengbu Railway Police CollegeBengbu 233000Anhui ProvinceChina

BACKGROUND Peptic ulcer is a common gastrointestinal disease,and psychological intervention has an important influence on its occurrence and *** To investigate the effect of psychological nursing intervention on the anxiety level and quality of life of patients with gastrointestinal peptic *** Two groups of patients with peptic ulcer were selected from January to December 2012,with 60 cases in each group,and psychological nursing intervention and routine treatment were respectively *** nursing interven-tions include cognitive behavioral therapy,psychological support and relaxation ***-rating anxiety scale(SAS)and quality of life questionnaire were used to evaluate the anxiety level and quality of life of patients before,during and after *** The SAS scores of the experimental group significantly decreased over the course of treatment,from 52.3 before treatment to 30.5 after treatment,while SAS scores of the control group did not change ***,the experimental group's quality of life score(SF-36)significantly improved over the course of treatment,from 65.2 to 85.2,while the control group remained *** analysis showed that sex and age had no significant influence on the effect of *** men and women,young and old,showed similar trends in anxiety relief and improved quality of life after *** Psychological nursing-based intervention program has a positive effect on the anxiety level and quality of life of patients with gastrointestinal peptic ulcer.

关键词： Gastrointestinal peptic ulcer Psychological nursing Anxiety level Quality of life Cognitive behavioral therapy

Impact point prediction guidance of ballistic missile in high maneuver penetration condition

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Defence Technology（防务技术） 2023年第8期26卷 213-230页

作者： Yong Xian Le-liang Ren ya-jie xu Shao-peng Li Wei Wu Da-qiao Zhang Xi'an Research Institute of High Technology Xi'an710025China Department of Automation Tsinghua UniversityBeijing100084China

An impact point prediction(IPP) guidance based on supervised learning is proposed to address the problem of precise guidance for the ballistic missile in high maneuver penetration *** accurate ballistic trajectory model is applied to generate training samples,and ablation experiments are conducted to determine the mapping relationship between the flight state and the impact *** the same time,the impact point coordinates are decoupled to improve the prediction accuracy,and the sigmoid activation function is improved to ameliorate the prediction ***,an IPP neural network model,which solves the contradiction between the accuracy and the speed of the IPP,is *** view of the performance deviation of the divert control system,the mapping relationship between the guidance parameters and the impact deviation is analysed based on the variational *** addition,a fast iterative model of guidance parameters is designed for reference to the Newton iteration method,which solves the nonlinear strong coupling problem of the guidance parameter *** Carlo simulation results show that the prediction accuracy of the impact point is high,with a 3 σ prediction error of 4.5 m,and the guidance method is robust,with a 3 σ error of 7.5 *** the STM32F407 singlechip microcomputer,a single IPP takes about 2.374 ms,and a single guidance solution takes about9.936 ms,which has a good real-time performance and a certain engineering application value.

关键词： Ballistic missile High maneuver penetration Impact point prediction Supervised learning Online guidance Activation function