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以竞赛为驱导推动高校数学教学的探索与研究

林区教学 2025年第1期 61-64页

作者：古佳西安财经大学西安710071

数学竞赛形式多样,内容丰富,从基础数学到高等数学,从理论研究到实际应用,都是对学生数学能力的检验,也是对他们逻辑思维、问题解决能力以及创新能力的全面考查。尤其在素质教育不断深化的前提下,要以学生为中心,结合高校数学特点落实... 详细信息

数学竞赛形式多样,内容丰富,从基础数学到高等数学,从理论研究到实际应用,都是对学生数学能力的检验,也是对他们逻辑思维、问题解决能力以及创新能力的全面考查。尤其在素质教育不断深化的前提下,要以学生为中心,结合高校数学特点落实以赛促教,是当前数学教学创新的重要方向。针对当前竞赛与数学教学面临的难题,要在将竞赛融入日常教学、构建专业竞赛教师队伍、制定竞赛评价机制等方面进行实施,为高校数学教学带来新的活力和动力,培养更多具有创新能力和实践精神的高素质人才。

关键词：竞赛高校数学教学

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电网营销项目后评价研究

价值工程 2025年第3期44卷 59-61页

作者：赵睿姜于顾家伟国网浙江省电力有限公司杭州310007 国网浙江省电力有限公司平阳县供电公司平阳325400 国网浙江省电力有限公司嘉善县供电公司嘉善314100

本文针对电网营销项目特点,从项目后期管理、信息化水平、造价管控、效益等四个方面建立了一套科学、合理、全面的指标体系对其进行后评价。在此基础上,设计了后评价系统。通过该系统的应用,进一步提高了营销项目费用使用的合理性、合规... 详细信息

本文针对电网营销项目特点,从项目后期管理、信息化水平、造价管控、效益等四个方面建立了一套科学、合理、全面的指标体系对其进行后评价。在此基础上,设计了后评价系统。通过该系统的应用,进一步提高了营销项目费用使用的合理性、合规性,促进了项目精益化闭环管理,提高了电网企业决策水平和投资效益。

关键词：后期管理评价信息化水平评价造价管控评价效益评价后评价系统设计

Real-World COVID-19 Vaccine Protection Rates against Infection in the Delta and Omicron Eras

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Research 2023年第4期6卷 583-594页

作者： Yuru Zhu jia gu Yumou Qiu Song Xi Chen Center for Statistical Science Peking UniversityBeijingChina Department of Statistics Iowa State UniversityAmesIAUSA School of Mathematical Science and guanghua School of Management Peking UniversityBeijingChina Pazhou Lab GuangzhouChina

The real-world vaccine protection rates(VPRs)against the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection are critical in formulating future vaccination strategies against the *** on a varying coefficient stochastic epidemic model,we obtain 7 countries’real-world VPRs using daily epidemiological and vaccination data,and find that the VPRs improved with more vaccine *** average VPR of the full vaccination was 82%(SE:4%)and 61%(SE:3%)in the pre-Delta and Deltadominated periods,*** Omicron variant reduced the average VPR of the full vaccination to 39%(SE:2%).However,the booster dose restored the VPR to 63%(SE:1%)which was significantly above the 50%threshold in the Omicron-dominated *** analyses show that the existing vaccination strategies have significantly delayed and reduced the timing and the magnitude of the infection peaks,respectively,and doubling the existing booster coverage would lead to 29%fewer confirmed cases and 17%fewer deaths in the 7 countries compared to the outcomes at the existing booster taking *** call for higher full vaccine and booster coverage for all countries.

关键词： vaccine vaccination doses

Catalytic performance improvement of volatile organic compounds oxidation over MnO_(x) and GdMnO_(3) composite oxides from spent lithium-ion batteries:Effect of acid treatment

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Chinese Journal of Chemical Engineering 2021年第6期34卷 278-288页

作者： Mingming guo Lizhong Liu jia-nan gu Hongbo Zhang Xin Min jianxing Liang Jinping jia Kan Li Tonghua Sun School of Environmental Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China School of Chemistry and Chemical Engineering Nantong UniversityNantong 226019China School of Chemical and Environmental Engineering Shanghai Institute of TechnologyShanghai 201418China Shanghai Institute of Pollution Control and Ecology Security Shanghai 200092China Shanghai Engineering Research Center of SolidWaste Treatment and Resource Recovery Shanghai 200240China

In this work,cathode materials of spent lithium-ion ternary batteries are recovered and used as metal precursor to prepare multi-metal oxides MnO_(x)(SY)and GdMnO_(3)(SY)via combustion method and sol-gel method,***,a series of MnO_(x)(SY)-n and GdMnO_(3)(SY)-n(n=0.05,0.10,1.00,4.00,n represents the dilute HNO_(3) concentration)catalysts are fabricated by acid treatment of MnO_(x)(SY)and GdMnO_(3)(SY)samples and catalytic activities of oxygenated VOCs oxidation over all the prepared catalysts are *** evaluation results show that acid-treated MnO_(x)(SY)-0.10 and GdMnO_(3)(SY)-0.05 samples perform the optimum VOCs removal efficiency respectively,which may be attributed to their obvious enhancement of physicochemical *** detail,Mn O_(x)(SY)-0.10 and GdMnO_(3)(SY)-0.05 samples exhibit the larger specific surface area,bigger amount of surface high-valence metal ions(Mn^(4+),Co^(3+),Ni^(3+)),more abundant adsorbed oxygen species and better low-temperature reducibility,which can play a crucial role in the significant improvement of VOCs *** situ DRIFTS results imply that the possible main intermediates are-OCO,-COO and-C-O species produced during VOCs *** by-products are further determined via TD/GC-MS analysis.

关键词： Spent lithium-ions batteries Acid treatment Multi manganese-based oxides and perovskite VOCs oxidation

Chinese scientific productivity ranking the fifth

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中华医学杂志(英文版) 2004年第1期 156-157页

作者： gu jia, CMJ

Ultra-high cycle fatigue behavior of high strength steel with carbide-free bainite/martensite complex microstructure

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International Journal of Minerals,Metallurgy and Materials 2009年第3期16卷 285-292页

作者： Xue-xia Xu Yang Yu Wen-long Cui Bing-zhe Bai jia-lin gu Laboratory of Advanced Materials Department of Materials Science and Engineering Tsirtghua University Beijing 100084 China

The ultra-high cycle fatigue behavior of a novel high strength steel with carbide-free bainite/martensite （CFB/M） complex microstructure was studied. The ultra-high cycle fatigue properties were measured by ultrasonic fatigue testing equipment at a frequency of 20 kHz. It is found that there is no horizontal part in the S-N curve and fatigue fracture occurs when the life of specimens exceeds 10^7 cycles. In addition, the origination of fatigue cracks tends to transfer from the surface to interior of specimens as the fatigue cycle exceeds 10^7, and the fatigue crack originations of many specimens are not induced by inclusions, but by some kind of ＂soft structure＂. It is shown that the studied high strength steel performs good ultra-high cycle fatigue properties. The ultra-high fatigue mechanism was discussed and it is suggested that specific CFB/M complex microstructure of the studied steel contributes to its superior properties.

关键词： high strength steel ultra-high cycle fatigue bainite martensite fatigue behavior

Comparing containment measures among nations by epidemiological effects of COVID-19

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National Science Review 2020年第12期7卷 1847-1851页

作者： jia gu Han Yan Yaxuan Huang Yuru Zhu Haoxuan Sun Yumou Qiu Songxi Chen Center for Statistical Science Peking University guanghua School of Management Peking University School of Mathematical Sciences Sichuan University Yuanpei College Peking University Center for Data Science Peking University Department of Statistics Iowa State University

The coronavirus disease 2019 (COVID-19) has evolved to a global pandemic since its inception in December *** have responded to the epidemics with different levels of responses and containment *** the unprecedented pressure on nations’healthcare systems and the deaths so far,there is an urgent need to evaluate the effects of the containment measures,which would be useful for countries to plan for their responses to counter the first or possibly the second wave of the epidemic.

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Comparison of two types of colectomy in treating slow transit constipation with or without melanosis coli

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World Journal of Gastroenterology 2015年第33期21卷 9736-9740页

作者： Ji-Wei Sun jia-Ni gu Peng Du Wei Chen Department of Anal and Rectal Surgery Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine

AIM: To compare the follow-up outcomes of ileosigmoidal anastomosis(ISA) and caecorectal anastomosis(CRA) in patients with slow transit constipation(STC) with or without melanosis coli(MC).METHODS: We collected the clinical data of 48 STC patients with or without MC from May 2002 to May ***-six patients underwent CRA(14 with MC) and 22 cases received ISA(14 with MC).A 3-year postoperative follow-up was ***: CRA improved the quality of life [evaluated by the gastrointestinal quality of life index(GIQLI)] in patients without MC,but was inferior to ISA in stool frequency and Wexner and GIQLI scores for MC *** the CRA group,patients with MC suffered worse outcomes than those without ***: CRA is more suitable for STC patients without MC; however,for STC patients with MC,ISA is a better choice.

关键词： Constipation Melanosis coli Caecorectal anastomosi

Discrepancy in fine root turnover estimates between diameter-based and branch-order-based approaches:a case study in two temperate tree species

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Journal of Forestry Research 2012年第4期23卷 575-581页

作者： SUN Jing-jue gu jia-cun WANG Zheng-quan School of Forestry Northeast Forestry UniversityHarbin 150040China

Fine root turnover plays a key role in carbon （C） budgets and nutrients cycles in forest ecosystems. However, the difference between branch-order-based and diameter-based approaches in estimating fine root turnover is still unclear. We studied root biomass turnover based on multiplying root standing biomass by turnover rate （inverse of median root longevity） in two Chinese temperate tree species, Fraxinus mand- shurica Rupr. and Larix gmelinii Rupr. The minirhizotron （MR） tech- nique was used to estimate longevities for first and second order roots, and total roots （R,o,al） apparent on the MR tube surface. The correspond- ing biomass for each root group was estimated by soil monolith. The difference in biomass turnover between Rtotal and the sum of the first and second order roots was used to represent the discrepancy between di- ameter- and order-based approaches. First order roots had shorter life spans and higher biomass turnover rates than the second order roots in both species. Biomass turnover estimated by the order-based method for F. mandshurica and L. gmelinii were 155.4 *** 158.9 g.m2.a-1, respectively, in comparison with 99.5 g.m^-2-a^-1 and 117.7 g.m^-2.a^-1 estimated by the diameter-based method, indicating that the diameter-based approach underestimated biomass turnover. The most probable reason was that the order-based method enhanced separation of the heterogeneous root population into relatively homogenous root groups with varying turnover rates. We conclude that separating fine root pool into different branch orders can improve the accuracy of estimates for fine root turnover, as well as the understanding of the belowground C allocation and nutrient cycling at ecosystem level.

关键词： Fraxinus mandshurica root life span root longevity Larix gmelinii minirhizotron soil monolith