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Thiel-Behnke Corneal Dystrophy in a Young Man in Denmark—A Case Report
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作者 Sara Bøgelund Rasmussen Anders Peter Søndergaard 《Open Journal of Ophthalmology》 2024年第3期208-217,共10页
Background: This case report presents a case of bilateral Thiel-Behnke corneal dystrophy in Denmark. Thiel-Behnke is an autosomal dominant inherited epithelial-stromal TGFBI dystrophy causing visual impairment. Method... Background: This case report presents a case of bilateral Thiel-Behnke corneal dystrophy in Denmark. Thiel-Behnke is an autosomal dominant inherited epithelial-stromal TGFBI dystrophy causing visual impairment. Methods and Results: This case study presents a 24-year-old Lithuanian man, with no previous ocular history, who had experienced slowly progressive visual impairment since his childhood. He was examined at the Department of Ophthalmology at Vejle Hospital and Aarhus University Hospital, where he was diagnosed with bilateral Thiel-Behnke corneal dystrophy. Histology confirmed the diagnosis. A lamellar corneal transplantation was performed in the right eye;however, due to epithelial growth under the corneal graft, it was later decided to redo the operation. Following the operations, the patient experienced a visual improvement in best corrected visual acuity (BCVA) from 0.1 (20/25 Snellen equivalent) to 0.3 (20/40 Snellen equivalent) in his right eye. Conclusions: This case of Thiel-Behnke corneal dystrophy is to our knowledge the first reported case in Denmark. 展开更多
关键词 Thiel-Behnke Corneal Dystrophy Thiel-Behnke Corneal Dystrophy Honeycomb Dystrophy CORNEA
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Relationship between heavy metals and clay mineralogy of the modern sediment of salt marsh at the east coast of Wadden Sea, Denmark 被引量:1
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作者 Christian Christiansen Jesper Bartholdy 《Chinese Journal Of Geochemistry》 EI CAS 2006年第B08期172-173,共2页
关键词 盐沼 重金属 沉积物 矿物 生态系统
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Effect of Salinity-Changing Rates on Filtration Activity of Mussels from Two Sites within the Baltic Mytilus Hybrid Zone:The Brackish Great Belt(Denmark)and the Low Saline Central Baltic Sea 被引量:4
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作者 Hans Ulrik Riisgard Magali Mulot +1 位作者 Lucia Merino Daniel Pleissner 《Open Journal of Marine Science》 2014年第2期101-109,共9页
Mussels from two sites within the Baltic mussel (Mytilus edulis × M. trossulus) hybrid zone were used in a comparative study on the effects of salinity-changing rates on filtration activity. The acute effect of v... Mussels from two sites within the Baltic mussel (Mytilus edulis × M. trossulus) hybrid zone were used in a comparative study on the effects of salinity-changing rates on filtration activity. The acute effect of varying salinity-changing rates was found to be similar in M. edulis from the brackish Great Belt and in M. trossulus from the low saline Central Baltic Sea, and the relationships could be described by linear regression lines through 0.0 indicating that the acute effect of deteriorating conditions at decreasing salinities is the opposite as for improving conditions when the salinity is subsequently increased. Further, both M. edulis and M. trossulus acclimatized to 20 psu reacted to an acute salinity change to 6.5 psu by immediately closing their valves whereupon the filtration rate gradually increased during the following days, but only M. trossulus had completely acclimatized to 6.5 psu within 5 days which may be explained by different genotypes of M. edulis and M. trossulus which probably reflected an evolutionary adaptation of the latter to survive in the stable low-salinity Baltic Sea. 展开更多
关键词 Blue Mussels Mytilus edulis Mytilus trossulus Acute Salinity Effects ACCLIMATIZATION Filtration Rates
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Effect of Salinity on Growth of Mussels,Mytilus edulis,with Special Reference to Great Belt(Denmark) 被引量:3
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作者 Hans Ulrik Riisgard Line Bottiger Daniel Pleissner 《Open Journal of Marine Science》 2012年第4期167-176,共10页
The effects of salinities between 10 and 30 psu on the growth of blue mussels, Mytilus edulis, were studied in laboratory feeding experiments and compared to the growth of mussels suspended in net-bags in the brackish... The effects of salinities between 10 and 30 psu on the growth of blue mussels, Mytilus edulis, were studied in laboratory feeding experiments and compared to the growth of mussels suspended in net-bags in the brackish water Great Belt, Denmark. In the laboratory, 3 series of growth experiments were conducted: in Series #1, groups of mussels were exposed to 10, 15, 25 and 30 psu, in Series #2, two groups of mussels were exposed to 10 and 30 psu, respectively, for 15 days (first period) where upon the mussels were exposed to the reversed salinities for another 15 days (second period). In Series #3, two groups of mussels were initially exposed to 15 and 25 psu for 22 days whereupon the mussel groups were exposed to the reversed salinities for another 17 days. In the laboratory experiments there was a tendency towards reduced growth with decreasing salinity, reflected as reduced shell growth rate and decreasing weight specific growth rate with falling salinity. The shell growth rate was relatively low in the first feeding period compared to the second period, and mussels that were initially exposed to 10 psu, where the growth was low, exhibited fast growth when subsequently exposed to 30 psu, and reversed when 30 psu mussels were exposed to 10 psu. The study showed that mussels are able to adjust growth at changing salinities, and the observed effect of salinity could partly be explained by a temporary shell valve closure after a sudden change in salinity. The specific growth rate of mussels measured in laboratory experiments at salinities between 15 to 25 psu (4.2% to 4.8% d–1) were comparable to the growth of mussels in the field experiment (3.2% to 4.0% d–1) where the salinity varied between 24 and 13 psu during the growth period. 展开更多
关键词 Mussels Mytilus edulis Salinity Effects Growth Rates Condition Index Doubling Time
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A review of the day-ahead natural gas consumption in Denmark:starting point towards forecasting accuracy improvement
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作者 Orhan AltuğKarabiber George Xydis 《International Journal of Coal Science & Technology》 EI CAS CSCD 2021年第1期1-22,共22页
Natural gas consumption forecasting is crucial for transmission system operators,distribution system operators,traders,and other players in the market.This work collects natural gas forecasting scientific works in acc... Natural gas consumption forecasting is crucial for transmission system operators,distribution system operators,traders,and other players in the market.This work collects natural gas forecasting scientific works in accordance with the forecasting tool used by Energinet,the Danish transmission system operator.The work provides an analytical description on the long-term stability and security of the natural gas transmission system in Denmark.This work offers a detailed scientific directory on natural gas forecasting,presenting the so far vaguely described market in a more structured manner.The paper was focused on presenting the latest findings on identifying the selection each time of the appropriate prognostic model for each application based on:①the option for supporting double seasonality,②various exogenous variables,③suitability for day-ahead forecasting,and④ease of use and all these versus Energinet’s current model. 展开更多
关键词 Natural gas Forecasting Natural gas supply chain Gas infrastructure
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<i>Rhynchostegium megapolitanum</i>(Web. et Mohr) B.S.G.—A Rare Bryophyte in Dune Ecosystems of Zealand, Denmark
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作者 Ib Johnsen 《American Journal of Plant Sciences》 2014年第9期1378-1383,共6页
Rhynchostegium megapolitanum was observed during a study of the effects of the invasive nonnative Rosa rugosa in a sand dune. The vascular as well as the epiphytic and epigeic cryptogam vegetation was recorded., and s... Rhynchostegium megapolitanum was observed during a study of the effects of the invasive nonnative Rosa rugosa in a sand dune. The vascular as well as the epiphytic and epigeic cryptogam vegetation was recorded., and soil properties were measured. Epihytic lichens were abundant on dead or dying branches of Rosa rugosa scrubs, under which the stable substrate and high light exposure provided growth conditions for an epigeic community dominated by lichens and bryophytes. The occurrence of the rare bryophyte Rhynchostegium megapolitanum is discussed. 展开更多
关键词 Rosa RUGOSA Coastal Sand DUNE Epiphytic LICHENS Epigeic BRYOPHYTES
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Legal Framework as a Core Element of District Cooling Success—The Case of Denmark
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作者 Bent Ole Gram Mortensen 《Journal of Power and Energy Engineering》 2014年第9期41-48,共8页
This paper describes the Danish legal framework for district cooling as an example of a model which so far has had limited success. A number of suggestions are analysed and discussed.
关键词 DISTRICT HEATING DISTRICT COOLING LEGAL Framework
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Increasing Incidence of Extended-Spectrum Beta-Lactamase-Producing Enterobacteriaceae (ESBL) and the Relation to Consumption of Broad-Spectrum Antimicrobial Agents 2003-2011 in a Large Area of Copenhagen, Denmark
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作者 Lene Nielsen Anne Kjerulf Magnus Arpi 《Open Journal of Medical Microbiology》 2015年第1期28-42,共15页
Purpose: To investigate 1) the development in the incidence of ESBL-producing bacteria in hospitals and primary health care, 2) the contribution of primary health care to the incidence of ESBL-producing bacteria, and ... Purpose: To investigate 1) the development in the incidence of ESBL-producing bacteria in hospitals and primary health care, 2) the contribution of primary health care to the incidence of ESBL-producing bacteria, and 3) the development in resistance patterns for all Escherichia coli and Klebsiella pneumoniae isolates in relation to antimicrobial consumption in hospitals and primary health care. Methods: ESBL-data were retrospectively collected from bacterial isolates from all specimens received at the Department of Clinical Microbiology from 2003 to 2011 together with the corresponding patient data. ESBL-production was detected in isolates from 1067 of 59,373 patients (1.8%) with an E. coli infection and in 263 of 8660 patients (3.0%) with a K. pneumoniae infection. Results: From 2003 to 2009, an increase in patients with an ESBL-producing isolate occurred in both hospitals and primary health care at the same time as an increased consumption of broad-spectrum antimicrobial agents was seen. Interventions to reduce prescription of cephalosporins and ciprofloxacin at the hospitals from 2010 resulted in a remarkable decrease in patients with ESBL-producing K. pneumoniae whereas a continuing increase was seen in patients with ESBL-producing E. coli both at hospitals and in primary health care. The proportion of patients with community-acquired ESBL-producing E. coli was stable with an increase of only 1.4% from 2007 to 2011. Conclusions: Reduction in prescription of broad-spectrum antimicrobial agents at the hospital level had an important impact on the incidence of ESBL-producing K. pneumoniae, but not on ESBL-producing E. coli. 展开更多
关键词 Incidence of ESBL-Producing E. coli and K. pneumoniae Hospital CARE Primary Health CARE ANTIMICROBIAL CONSUMPTION BROAD-SPECTRUM ANTIMICROBIAL Agents
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Tourist Attraction Development in Denmark and Its Impact on Regions
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作者 Jie Zhang 《Management Studies》 2014年第4期254-268,共15页
This paper presents an investigation on the definitions of different concepts within cultural, tourism and creative industries, and experienced economy. The statistical approach is used in this analysis, both relating... This paper presents an investigation on the definitions of different concepts within cultural, tourism and creative industries, and experienced economy. The statistical approach is used in this analysis, both relating to the data presentation and the application of the Danish regional model for the economic assessment of tourist attraction. The research aim of the paper is two-fold: firstly, to discuss and highlight the development of cultural and tourist attractions both at national and regional level; secondly to show that tourist attractions play an important role both in destination marketing and the economic contribution to the Danish regions. The paper describes the trends of cultural and tourist attractions in Denmark both in the economic terms and in terms of numbers of visitors at attractions. Tourist attractions have an effect on tourists' choice of their destination. The last part of the paper focuses on the case studies within which the economic impacts of tourist attraction on the regions are presented. The Danish inter-regional model is applied for analyzing the economic and employment effects of these tourist attractions. The conclusion is drawn in the last section. 展开更多
关键词 tourism attractions cultural tourism national accounts for culture industry economic impact
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Ammonia Emissions in EuropemCosts, Regulation and Targets with Focus on Denmark
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作者 Brian H Jacobsen 《Journal of Agricultural Science and Technology(A)》 2012年第3期285-293,共9页
The NEC (National Emission Ceiling) directive has set targets for the 2010 ammonia emissions from a number of European countries. The target will be reached by most EU-countries and the total emission for EU-27 has ... The NEC (National Emission Ceiling) directive has set targets for the 2010 ammonia emissions from a number of European countries. The target will be reached by most EU-countries and the total emission for EU-27 has been reduced by 22% from 1990 to 2007. Denmark is one of the countries with the largest reductions since 1990 and the article aims at the measures and costs involved. The conclusion is that the costs have been under 3ε per kg NH3-N. Measures in several countries are under 5ε per kg NH3-N, which is a likely minimum for the benefits of reducing NH3-N. The findings suggest that the same measures might be cheaper in the Netherlands and Denmark than in the UK and the USA due to technology advances and stricter regulations in the past. The new Danish application procedure, when increasing the animal production, has tried to make the acceptance procedure quicker and dynamic ensuring that new technology is adopted quicker and that the farm has the right location. It is concluded that the new application process so far has not lived up to the high expectations at the outset. Despite this, the paper concludes that Denmark is likely to reduce emission by 50% from 1990 to 2020 and reach the likely 2020 NEC ceiling. 展开更多
关键词 Ammonia emission COSTS cost effective measores NEC directive and regulation.
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Modelling Recycling Targets:Achieving a 50%Recycling Rate for Household Waste in Denmark
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作者 Amanda Louise Hill Ole Leinikka Dall Frits Moller Andersen 《Journal of Environmental Protection》 2014年第7期627-636,共10页
Within the European Union (EU) a paradigm shift is currently occurring in the waste sector, where EU waste directives and national waste strategies are placing emphasis on resource efficiency and recycling targets. Th... Within the European Union (EU) a paradigm shift is currently occurring in the waste sector, where EU waste directives and national waste strategies are placing emphasis on resource efficiency and recycling targets. The most recent Danish resource strategy calculates a national recycling rate of 22% for household waste, and sets an ambitious goal of a 50% recycling rate by 2020. This study integrates the recycling target into the FRIDA model to project how much waste and from which streams should be diverted from incineration to recycling in order to achieve the target. Furthermore, it discusses how the existing technological, organizational and legislative frameworks may affect recycling activities. The results of the analysis show that with current best practice recycling rates, the 50% recycling rate cannot be reached without recycling of household biowaste. It also shows that all Danish municipalities will need to make efforts to recover all recyclable fractions, and that the increased recycling efforts of only selected municipalities will not be sufficient to reach the target. 展开更多
关键词 Recycling Rate Recycling Potential Household Waste Econometric Modeling Waste Management
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Atmospheric Trajectory and Chemical Transport Modelling for Elevated Ozone Events in Denmark
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作者 Alexander Mahura Roman Nuterman +1 位作者 Irina Petrova Bjarne Amstrup 《Atmospheric and Climate Sciences》 2013年第1期87-99,共13页
In this study, three Danish sites having the longest (1990-2004) time-series of ozone measurements were analysed on inter-annual, monthly and diurnal cycle variability as well as elevated and lowered ozone concentrati... In this study, three Danish sites having the longest (1990-2004) time-series of ozone measurements were analysed on inter-annual, monthly and diurnal cycle variability as well as elevated and lowered ozone concentration events were identified. The atmospheric trajectory (HYSPLIT) and dispersion (HIRLAM + CAMx) models were employed to study dominating atmospheric transport patterns associated with elevated events and to evaluate spatio-temporal variability of ozone specific episode and typical seasonal patterns for Denmark. It was found that generally inter-annual variability has a positive trend, and events with low ozone concentration (≤10 μg/m3) continued to diminish. On a monthly scale, the highest and lowest mean concentrations are observed in May and November-December, respectively. The elevated concentrations (≥120 μg/m3) are observed during March-September. On a diurnal cycle, it is observed mostly during 13-16 of local time, and more frequent (ten-fold) compared with nighttime-early morning hours. For ozone elevated events, several sectors (or pathways of atmospheric transport) were identified depending on the sites’ positions, showing the largest (39%) number of such events associated with the north-western sector, and lowest (13% each)—southwestern and northern sectors. For each site, less than 60 events showed very high concentrations (≥180 μg/m3). Among 12 episodes, one longest elevated episode (19-21 Jun 2000) simultaneously registered at all sites and characterized by dominating transport from the south-southwestern sector, low wind speed, clear-sky, and multiple inversions was studied using modelling tools. For this episode, both measurements and modeling (trajectory and dispersion) results showed a relatively good agreement. 展开更多
关键词 ELEVATED Ozone Concentration Event and EPISODE ATMOSPHERIC TRAJECTORY Chemical Transport Modeling HYSPLIT HIRLAM CAMX
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The Economic Burden of Head and Neck Cancers in Denmark
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作者 Jens Olsen Tine Rikke Jorgensen Niclas Rubek 《International Journal of Otolaryngology and Head & Neck Surgery》 2013年第3期103-109,共7页
Introduction: The incidence of head and neck cancers has increased markedly over the last decade. A Danish study of the costs of head and neck cancers has not been undertaken. Such studies have again become relevant d... Introduction: The incidence of head and neck cancers has increased markedly over the last decade. A Danish study of the costs of head and neck cancers has not been undertaken. Such studies have again become relevant due to the development of the HPV vaccines, as some cases are attributable to high-risk HPV 16 or 18. The objective of study was to estimate the incidence of head and neck cancers and their health care costs. Methods: Data on incidence and health care use related to head and neck cancer were obtained from Danish health care registers. New cancer patients were identified in the Danish National Cancer Register. Resource use per year in the hospital sector was estimated using data from the National Patient Register applying charges as cost estimates. Health care consumption by cancer patients was compared with that by an age- and sex-matched cohort without cancer. Results: We found that nearly 1000 new cases of oral cavity, oropharyngeal, hypopharyngeal and laryngeal cancer are diagnosed annually. In total the cost of these cancers to the Danish hospital sector constituted 31.6 million Euros per year, with the majority of costs (74%) occurring in men. The total costs associated with HPV16/18-related head and neck cancers were estimated to be 6.1 million Euros per year. Conclusion: This study provides the first Danish estimates of the costs associated with non-cervical and non-genital HPV-related cancers based on very reliable, individual-based data. It is expected that the current HPV vaccination programme will reduce this burden. 展开更多
关键词 Head and Neck Cancer COST-OF-ILLNESS Human Papilloma Virus(HPV)Infections
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Risk of cardiovascular disease among parents of children diagnosed with cancer:a population-based study from Denmark and Sweden
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作者 Qianwei Liu Krisztina D László +7 位作者 Dang Wei Carsten Obel Fen Yang Katja Fall Unnur Valdimarsdóttir Maria Feychting Jiong Li Fang Fang 《Cancer Communications》 SCIE 2023年第7期834-837,共4页
Dear Editor,Receiving a cancer diagnosis is a traumatic life event that impacts not only the patients but also their families[1].Parents of patients with a cancer diagnosed in early life might experience a life crisis... Dear Editor,Receiving a cancer diagnosis is a traumatic life event that impacts not only the patients but also their families[1].Parents of patients with a cancer diagnosed in early life might experience a life crisis with various negative emotions,including the difficult decision-making in cancer treatment,concerns related to the side effects of the treatment and comorbidities,the worry for progression and relapse of the cancer and the risk of loss of the child due to death,as well as the physical demand of caregiving[2,3]. 展开更多
关键词 CANCER diagnosis TRAUMATIC
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基于虚拟电力系统稳定器的低频振荡抑制策略
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作者 王海鑫 何海文 +4 位作者 刘铭崎 杨子豪 郝炎 杨俊友 陈哲 《电机与控制学报》 EI CSCD 北大核心 2024年第5期82-90,100,共10页
基于虚拟同步发电机(VSG)控制的新能源机组虽可增强电网惯量及频率稳定性,但可能继承与同步机类似的低频振荡问题。针对该问题,首先基于单台VSG并网的线性化模型,构建了适用于VSG的Phillips-Heffron模型,借助阻尼转矩法挖掘了VSG低频振... 基于虚拟同步发电机(VSG)控制的新能源机组虽可增强电网惯量及频率稳定性,但可能继承与同步机类似的低频振荡问题。针对该问题,首先基于单台VSG并网的线性化模型,构建了适用于VSG的Phillips-Heffron模型,借助阻尼转矩法挖掘了VSG低频振荡的诱发机理。进一步提出一种附加于VSG无功环节的虚拟电力系统稳定器(VPSS),并给出了控制结构及基于相位补偿法的参数设计过程。研究结果表明:VSG发生低频振荡是由于系统受扰后,虚拟功角的振荡信号经过虚拟励磁调节器对VSG机电振荡回路产生了负阻尼转矩。将所提VPSS接入系统可在几乎不影响振荡频率的前提下,实现0.1~3 Hz下VSG低频振荡的有效抑制。 展开更多
关键词 虚拟同步发电机 虚拟电力系统稳定器 低频振荡 阻尼转矩分析 相位补偿法
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考虑灵活性资源和多能共享的低碳区域综合能源系统联盟-配电网博弈优化调度 被引量:5
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作者 高瑞阳 王新宝 +3 位作者 高娴 王芳 卞海红 徐懂理 《南方电网技术》 CSCD 北大核心 2024年第2期77-88,共12页
随着全国碳交易市场政策落地,为充分挖掘区域综合能源系统(regional integrated energy system,RIES)低碳减排能力,提高多区域综合能源系统接入主动配电网(active distribution network,ADN)的经济交互效益,提出了考虑灵活性资源与低碳... 随着全国碳交易市场政策落地,为充分挖掘区域综合能源系统(regional integrated energy system,RIES)低碳减排能力,提高多区域综合能源系统接入主动配电网(active distribution network,ADN)的经济交互效益,提出了考虑灵活性资源与低碳交互结构的区域综合能源系统联盟参与配电网调峰调度的优化调度策略。建立了以主动配电网为主体,区域综合能源系统联盟为从体的主从博弈模型。主体以最大化交互效益目标制定分时电价策略,从体成员间通过联络线实现多能共享,考虑碳交易制度以供能与碳交易成本之和最小为目标,响应主体电价策略,建立了下层多区域综合能源系统联盟合作博弈优化模型。引入包含需求响应、储能和电动汽车在内的灵活性资源,配合碳捕集-电转气耦合机组优化联盟内部各系统的低碳供能策略,满足联盟负荷需求。基于纳什议价理论完成联盟成员合作收益的分配。通过算例验证所提策略能够有效减少各区域综合能源系统碳排放,并保障主从交互经济效益。 展开更多
关键词 灵活性资源 多能共享 碳捕集 纳什议价 主从博弈 区域综合能源系统
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以掺氢天然气为燃料直接内重整固体氧化物电池堆的稳定性 被引量:1
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作者 汤亚飞 武安祺 +6 位作者 韩贝贝 刘华 包善军 林王林 陈铭 官万兵 Subhash C.Singhal 《电化学(中英文)》 CAS 北大核心 2024年第1期46-54,共9页
本文研究了掺氢天然气直接内重整平管型固体氧化物电池短堆的长期稳定性和衰减机理。通过约3000小时的实测实验,结果显示,电堆的总体衰减率为2.3%·kh^(-1),电堆中三个金属连接板的面积比电阻分别增加了0.276Ω·cm^(2)、0.254... 本文研究了掺氢天然气直接内重整平管型固体氧化物电池短堆的长期稳定性和衰减机理。通过约3000小时的实测实验,结果显示,电堆的总体衰减率为2.3%·kh^(-1),电堆中三个金属连接板的面积比电阻分别增加了0.276Ω·cm^(2)、0.254Ω·cm^(2)和0.249Ω·cm^(2),但电堆中两个电池的电压反而分别增加了3.38 m V·kh^(-1)和3.78 m V·kh^(-1)。电堆衰减主要由金属连接件表层氧化及其与阴极集流层材料反应生成Sr CrO_(4)物质,两者共同作用增大了电池与金属连接体间的界面电阻所致。结果表明,以掺氢天然气为燃料直接内重整平管型固体氧化物燃料电池电堆具有良好的稳定性。本文工作为掺氢天然气在固体氧化物燃料电池堆中的直接内重整应用提供了理论参考与实验依据。 展开更多
关键词 掺氢天然气 内重整 稳定性 固体氧化物电堆
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羟基四醚生物标志物指示长江口全新世环境演变的研究
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作者 袁梦 肖文杰 +3 位作者 年小美 张卫国 葛黄敏 许云平 《海洋科学》 CAS CSCD 北大核心 2024年第7期22-32,共11页
长江口作为中国最大的河口,其沉积物记录了东亚季风演化及海陆变迁的丰富信息,是研究环境演化的理想区域。脂类生物标志物具有特定的生物来源,对外部环境变化响应敏感且具有较高的保存潜力,是一类重要的古环境代用指标。本研究在长江口... 长江口作为中国最大的河口,其沉积物记录了东亚季风演化及海陆变迁的丰富信息,是研究环境演化的理想区域。脂类生物标志物具有特定的生物来源,对外部环境变化响应敏感且具有较高的保存潜力,是一类重要的古环境代用指标。本研究在长江口横沙岛采集了一根40m长的沉积柱样(HSD22),运用高效液相色谱质谱联用仪分析了微生物细胞膜脂的生物标志物——甘油二烷基甘油四醚(GlycerolDialkyl Glycerol Tetraethers;GDGTs),计算了BIT(Branched Isoprenoid Tetraether)、MI(Methane Index)、RI-OH(the ring index of OH-GDGTs)等分子指标,着重对羟基化GDGTs(OH-GDGTs)指标进行了研究。对比前人研究结果后发现OH-GDGTs具有环境特异性,不同环境中的生物来源不同,导致化合物的变化趋势不同。基于OH-GDGTs温度指标, HSD22的三次沉积相变换分别对应全新世的早期偏冷、中期偏暖、晚期偏冷的气候模式。此外,OH-GDGTs还显示出指示盐度变化和甲烷活动的潜力,OH/ALL%指标可以有效反映河口区域淡水信号的变化,但该指标在非河口区的适用性还有待进一步验证。 展开更多
关键词 长江口 GDGTs 盐度 甲烷
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基于数字孪生与多模型融合的多元负荷短期预测
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作者 冯佳威 王海鑫 +3 位作者 杨子豪 陈哲 李云路 杨俊友 《太阳能学报》 EI CAS CSCD 北大核心 2024年第10期97-106,共10页
针对多元负荷呈波动性和非线性特性导致预测模型稳定性差和精确度低等问题,提出一种基于数字孪生与多模型融合的多元负荷短期预测方法。首先,根据数字孪生体中气象和负荷信息,利用最大信息系数(MIC)分析多源数据信息间的耦合特性,基于... 针对多元负荷呈波动性和非线性特性导致预测模型稳定性差和精确度低等问题,提出一种基于数字孪生与多模型融合的多元负荷短期预测方法。首先,根据数字孪生体中气象和负荷信息,利用最大信息系数(MIC)分析多源数据信息间的耦合特性,基于数据时序性和周期性构建筛选信息特征。其次,采用自适应局部迭代滤波(ALIF)将历史多元负荷数据进行分解,得到不同频率下固有模态函数(IMF)分量。然后,采用核极限学习机(KELM)和双向长短期记忆网络(BiLSTM)预测高频和低频负荷分量,融合重构得到初始负荷短期预测结果。最后,利用数字孪生体补偿初始预测结果,得到最终负荷预测结果。仿真结果表明,与单预测模型及未基于数字孪生预测模型相比,所提方法具有更好的稳定性,能有效应对负荷波动变化和非线性,提升模型预测精度。 展开更多
关键词 数字孪生 负荷预测 自适应滤波 新型电力系统 核极限学习机 双向长短期记忆网络
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双层单原子催化剂用于促进高活性和选择性电催化硝酸盐还原制氨 被引量:2
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作者 于镜坤 雍雪 +1 位作者 曹昂 卢思宇 《物理化学学报》 SCIE CAS CSCD 北大核心 2024年第6期60-62,共3页
高效、高选择性的单原子催化剂(SACs)在电催化硝酸盐还原制氨过程中具有重要作用。然而,由于中间体、金属活性中心和配位环境之间复杂的竞争性电子相互作用,仍然面临挑战。本研究采用密度泛函理论(DFT)计算,对27种SACs以及双层SACs(BSA... 高效、高选择性的单原子催化剂(SACs)在电催化硝酸盐还原制氨过程中具有重要作用。然而,由于中间体、金属活性中心和配位环境之间复杂的竞争性电子相互作用,仍然面临挑战。本研究采用密度泛函理论(DFT)计算,对27种SACs以及双层SACs(BSACs)进行了系统研究,通过轴向d-d轨道杂化提高了从SACs到BSACs的电催化硝酸盐还原反应(NO_(3)RR)的活性和选择性。考虑到可能的O端、N端、NO端和NO二聚体途径,计算结果显示,在单层SACs中,Ti-Pc和V-Pc分别具有优异的极限电位(U_(L)),分别为-0.24和-0.48V。形成能、溶解势以及从头算分子动力学结果表明,在反应条件下,这些催化剂非常稳定。在这些单层TM-Pc中,它们的d带能级和占据数受到d_(xz)/d^(yz)和p_(z)轨道杂化的影响。其轴向d_(z^(2))轨道的可用性通过形成d_(z^(2))-d_(z^(2))相互作用来进一步调整d带和反应性。在此基础上,以Ti-Pc和V-Pc为底物,通过形成轴向d-d轨道杂化来构建BSACs,为调节NO_(3)RR催化性能提供了一种独特的新途径。重要的是,我们发现d带中心(εd)、d_(xz)+d_(yz)轨道的占据数和U_(L)之间存在二维火山关系,用于描述它们的NO_(3)RR催化性能。最佳的BSACs应该同时具备适当的ε_(d)和d_(xz)+d_(yz)占用数。Ti-Mo和Ti-Ta被确定为出色的NO_(3)RR催化剂,其U_(L)均降低至-0.13 V。而d_(z^(2))-d_(z^(2))轨道之间的杂化则增强了双层金属之间的电荷转移和结构稳定性。缺乏相邻的金属位点将导致生成NO_(2)、NO和N_(2)的能垒较高,从而抑制副产物生成。最终,本研究揭示了在SACs和BSACs上对硝酸盐还原进行合理优化的方法,可为改进电催化剂的设计提供指导。 展开更多
关键词 硝酸盐还原 第一性原理计算 单原子催化剂 双层单原子催化剂 轴向轨道杂化
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