检索结果-南通市图书馆

维普期刊数据库博看期刊

在线全文

学校读者我要写书评

暂无评论

钒钛铁尾矿制备绿色建筑材料的研究进展

材料导报 2024年第19期38卷 115-124页

作者：田小平王长龙 Hidayati Asrah lim Chung Han 平浩岩齐洋马锦涛荆牮霖刘治兵郑永超翟玉新刘枫河北工程大学土木工程学院河北邯郸056038 马来西亚沙巴大学工程学院沙巴哥打京那巴鲁88400 北京建筑材料科学研究总院有限公司固废资源化利用与节能建材国家重点实验室北京100041 中铁建设集团有限公司北京100040 中铁建设集团建筑发展有限公司北京100070

钒钛磁铁矿是以铁、钒、钛为主的多金属元素共生的复合矿,在世界分布不均衡。中国是该矿石的主要产出国之一,该矿石分布在五个主要矿带。钒钛铁尾矿是钒钛磁铁矿选矿过程中产生的固体工业废弃物,是一种多金属伴生的铁尾矿。该尾矿在中... 详细信息

钒钛磁铁矿是以铁、钒、钛为主的多金属元素共生的复合矿,在世界分布不均衡。中国是该矿石的主要产出国之一,该矿石分布在五个主要矿带。钒钛铁尾矿是钒钛磁铁矿选矿过程中产生的固体工业废弃物,是一种多金属伴生的铁尾矿。该尾矿在中国的堆存量巨大,富含很多有用化学组分,也被称为人工矿床。该尾矿以硅酸盐为主,主要化学成分是二氧化硅、三氧化二铝、氧化钙和氧化铁等,主要矿物是脉石矿物。国内外学者对其在绿色建筑材料综合利用方面做了很多有益探索,但总体来看,这些研究更多停留在实验室里。主要原因是(1)不同尾矿库甚至同一尾矿库的钒钛铁尾矿理化性能可能有较大差异,尾矿原料的稳定性不足;(2)受尾矿原料不稳定的理化性能影响,中试结果经常出现较大差异,难以实现规模化利用;(3)钒钛铁尾矿库大多地处偏僻,运输成本高,且缺乏高附加值的尾矿产品,规模以上企业因投入大产出小望而生畏。本文综述了钒钛铁尾矿在中国的地域分布和堆存量,重点研究了其化学组成、矿物组成、粒度分布和重金属浸出,分析了其作为主要原料在绿色建筑材料方面的研究进展,指出了存在问题并展望了发展前景。

关键词：钒钛磁铁矿钒钛铁尾矿绿色建筑材料混凝土矿物掺合料

Characterizations of organic compounds in diesel exhaust particulates

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2015年第8期27卷 171-183页

作者： Jaehyun lim Cheolsoo lim Sangkyun Kim Jihyung Hong Division of Global Environment Research National Institute of Environmental Research Department of Climate and Air Quality Research National Institute of Environmental Research

To characterize how the speed and load of a medium-duty diesel engine affected the organic compounds in diesel particle matter（PM） below 1 μm, four driving conditions were examined. At all four driving conditions, concentration of identifiable organic compounds in PM ultrafine（34–94 nm） and accumulation（94–1000 nm） modes ranged from 2.9 to 5.7 μg/m3 and 9.5 to 16.4 μg/m3, respectively. As a function of driving conditions, the non-oxygencontaining organics exhibited a reversed concentration trend to the oxygen-containing organics. The identified organic compounds were classified into eleven classes： alkanes,alkenes, alkynes, aromatic hydrocarbons, carboxylic acids, esters, ketones, alcohols, ethers,nitrogen-containing compounds, and sulfur-containing compounds. At all driving conditions,alkane class consistently showed the highest concentration（8.3 to 18.0 μg/m3） followed by carboxylic acid, esters, ketones and alcohols. Twelve polycyclic aromatic hydrocarbons（PAHs）were identified with a total concentration ranging from 37.9 to 174.8 ng/m3. In addition, nine nitrogen-containing polycyclic aromatic compounds（NPACs） were identified with a total concentration ranging from 7.0 to 10.3 ng/m3. The most abundant PAH（phenanthrene）and NPACs（7,8-benzoquinoline and 3-nitrophenanthrene） comprise a similar molecular（3 aromatic-ring） structure under the highest engine speed and engine load.

关键词： Diesel particle matter Organic compounds Polycyclic aromatic hydrocarbons Nitrogen-containing polycyclic aromatic compounds

Landau damping of twisted waves in Cairns distribution with anisotropic temperature

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2021年第8期23卷 18-28页

作者： Sunggeun LEE Hankwon lim School of Energy and Chemical Engineering UNIST50UNIST-gilEonyang-eupUlju-gunUlsan 44919Republic of Korea

The consideration of orbital angular momentum of an electric field(twisted mode)is applied to the kinetic theory of *** linearized Vlasov–Poisson equation is solved for the anisotropic thermal distributed bi-Maxwellian and Cairns distributions of electrons to obtain the damping rates of twisted *** dispersion relation and Landau damping of Langmuir twisted modes are *** presence of twisted modes opens up two more possibilities in Landau damping and dispersion *** may generate a mixture with ion sound *** seems to play the role of a control parameter of Landau damping.

关键词： Landau damping Cairns distribution function anisotropic

Associated Factors to Poor Blood Pressure Control in Hypertensives Followed Up at the Campus University Hospital of Lome (Togo)

在线全文

学校读者我要写书评

暂无评论

World Journal of Cardiovascular Diseases 2024年第6期14卷 374-380页

作者： Soulemane Pessinaba Yaovi Mignazonzon Afassinou Wiyao Dieudonné Kaziga Komlavi Yayehd Kolani Lamboni Sélim Bolarinwa Mohamed Kpélafia Ekpe Togbossi Akpe Adzodo Machihude Pio Soodougoua Baragou Findibé Damorou Cardiology Department University Hospital of Campus Lome Togo Cardiology Department Sylvanus Olympio University Hospital Lome Togo Cardiology Department Kara University Hospital Kara Togo

Introduction: Hypertension is a real public health issue and its control is very difficult. We aim to determine the frequency of uncontrolled hypertension in hypertensive patients followed up as an outpatient at the campus university hospital of Lome (Togo) and to search for the associated factors. Methodology: The study was cross-sectional, descriptive and analytical, carried out from February (2022) to August 2022 in 260 hypertensive patients aged 22 years old, followed up (on an) as an outpatient for at least 3 months at the Lome University Hospital campus. A univariate then multivariate analysis were conducted in order to highlight the most common factors significantly linked to uncontrolled. Results: The mean age of hypertensives was 56.4 ± 12.7 years, the sex ratio (M/F) was 0.59. Prevalence of uncontrolled blood pressure was 42%. Associated Factors to poor blood pressure control in our study were age > 60 years (OR = 1.6 CI [1.17 - 2.50]), low socio-economic level (OR = 2.2 CI [1.96 - 4.33]), high cardiovascular risk level (OR = 3.1 CI [2.18 - 4.52]), non-adherence to regular blood pressure monitoring (OR = 3.3 CI [2.21 - 5.55]), low compliance to treatment (OR = 4.1 CI [2.33 - 6.76]) and a chronic renal failure (OR = 2.1 CI [1.21 - 3.10]). Conclusion: Nearly half of the hypertensives in our study had poorly controlled blood pressure by antihypertensive treatment medication. The factors of this poor control were age > 60 years, low socio-economic level, high or very high level of cardiovascular risk, low compliance to treatment, and renal failure.

关键词： Hypertension Poor Control Associated factors Togo

Emissions of Er3+ and Yb3+ co-doped SrZrO3 nanocrystals under near-infrared and near-ultraviolet excitations

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Advanced Ceramics 2020年第4期9卷 413-423页

作者： Hyeontae lim Juyeong lim Soyoung Jang Y.S.Lee Department of Physics Soongsil UniversitySeoul06978Republic of Korea

In this study,the upconversion(UC)emissions of Er3+and Yb3+co-doped SrZrO3 nanocrystals(NCs)were investigated in terms of the thermal annealing temperature and concentration of Er3+ions and compared with the emissions under a near-ultraviolet(near-UV)*** NCs were synthesized by the combustion method,and the as-synthesized NCs were post-annealed at high *** X-ray diffraction patterns revealed that the grain sizes and crystallinity degrees of the samples increased with increasing annealing *** photoluminescence spectra of our samples exhibited strong green and very weak red emissions with the near-UV excitation,originating from the f-f transitions in the Er3+***,under near-infrared(near-IR)excitation,we identified sizable visible emissions at 525,547,and 660 nm in our NCs,which indicated that the UC process successfully occurred in our *** UC emissions were maximized in the NCs with an Er3+concentration of 0.02 and thermal annealing at 1000°*** found that the intensity ratios of red to green emissions increased with increasing annealing *** discussed the differences in the emissions between near-UV and near-IR excitations.

关键词： Er3+and Yb3+co-doped SrZrO3 upconversion downshifting nanocrystals combustion method annealing temperature

Architecture for mobile group communication in campus environment

在线全文

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2013年第4期7卷 505-513页

作者： Yujin lim Sanghyun AHN Department of Information Media University of Suwon Hwaseong 445-743 Korea School of Computer Science University of Seoul Seoul 130-743 Korea

The demand for group communication using smart devices in campus environment is increasing rapidly. In this paper, we design an architecture for a mobile group communication system （MGCS） on campus by using Wi-Fi networks and smart devices. The architecture is composed of a web-based system and a smart device based mobile system. Through the systems, users on campus create community/mobile group, maintain dynamic group membership, and reliably deliver the message to other users. We use the common features of many smart devices to develop a prototype that works on off-the-shelf hardware. In the experimental section, we demonstrate our system using various real scenarios which can occur in university campuses.

关键词： smart campus smartphone location tracking,mobile community

Polarity control of carrier injection for nanowire feedback field-effect transistors

在线全文

学校读者我要写书评

暂无评论

Nano Research 2019年第10期12卷 2509-2514页

作者： Doohyeok lim Sangsig Kim Department of Electrical Engineering Korea University145 Anam-roSeongbuk-guSeoul 02841Republic of Korea

We present polarity control of the carrier injection for a feedback field-effect transistor(FBFET)with a selectively thinned p^+-i-n^+Si nanowire(SiNW)channel and two separate *** SiNW FBFET can be reconfigured in the p-or n-channel operation modes via simple control of electric *** two separate gates induce potential barriers in the SiNW channel for selective control of the carrier *** contrast to previously reported rec on figurable tran sistors,our tran sistor features symmetry of the electrical characteristics for the p-and n-cha nnel operation ***-feedback operation of the SiNW FBFET provides superior switching characteristics for the p-and n-type 8nfigurations,including the on/off ratios(~10^5)and subthreshold swings(1.36-1.78 mV/dec).This novel tran sistor is a promising can didate for reconfigurable electro nics.

关键词： silicon nanowire reconfigurable transistor positive-feedback loop separate gate

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

色度域亮度域信息融合的监控视频重压缩取证

哈尔滨工业大学学报 2024年第5期56卷 46-55页

作者：公衍超王子琳杨楷芳刘颖林庆帆王富平西安邮电大学通信与信息工程学院西安710121 西安邮电大学、陕西省法庭科学电子信息实验研究中心西安710121 西安邮电大学、陕西省无线通信与信息处理技术国际联合研究中心西安710121 陕西师范大学计算机科学学院西安710119 新加坡XsecPro公司新加坡787820

为解决当前视频重压缩取证方法没有考虑色度域信息、取证准确度低的问题,提出一种面向最新多用途视频编码(versatile video coding,VVC)标准色度域亮度域信息融合的监控视频重压缩取证方法(CLF-SVRF)。基于VVC标准的编码原理,从监控视... 详细信息

为解决当前视频重压缩取证方法没有考虑色度域信息、取证准确度低的问题,提出一种面向最新多用途视频编码(versatile video coding,VVC)标准色度域亮度域信息融合的监控视频重压缩取证方法(CLF-SVRF)。基于VVC标准的编码原理,从监控视频的色度域和亮度域维度分析并确定VVC视频码流中与压缩次数密切相关的基础码流特征;基础码流特征包括色度域和亮度域编码单元(coding unit,CU)的划分类型及预测模式;结合拉格朗日率失真优化技术分析随着压缩次数的增加,色度域亮度域CU划分类型和预测模式的变化;进一步确定色度域亮度域CU划分类型和预测模式可以作为检测视频压缩次数的基础码流特征;接着考虑视频监控应用对重压缩取证方法低复杂度的需求,基于色度域亮度域CU划分类型和预测模式构建低复杂度高级码流特征;将高级码流特征输入支持向量机完成监控视频的重压缩取证。实验结果表明,与当前先进方法相比,CLF-SVRF方法的监控视频重压缩取证准确度平均提升了13.53%,同时可以大幅度地降低重压缩取证耗时,重压缩取证时间平均减少了47.42%。

关键词：视频编码通用视频编码重压缩取证监控视频色度域

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

最大“禁氟令”前程飘摇

环球科学 2024年第3期 78-85页

作者：林晓智曾欣欣(译) 不详

2023年2月,一家欧洲机构提出了一项提案,计划禁止1万多种永久性化学物质的生产。如若实现,这将是迄今规模最大的禁氟令,但距离真正的实施还有很长一段路要走。

关键词：化学物质提案永久性