检索结果-南通市图书馆

Revisiting the Mg isotopic systematics of siliciclastic components of sediments and sedimentary rocks:A new geochemical proxy of continental weathering in Earth's history

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第2期67卷 620-633页

作者： Tianzheng HUANg Bing SHEN Kangjun HUANg Meng NINg Chao LI Jinzhuang XUE Yuanlin sun baoqi HUANg Key Laboratory of Orogenic Belt and Crustal Evolution MOESchool of Earth and Space SciencesPeking UniversityBeijing100871China State Key Laboratory of Continental Dynamics Shaanxi Key Laboratory of Early Life and EnvironmentsDepartment of GeologyNorthwest UniversityXi’an710069China Institute of Sedimentary geology Chengdu University of TechnologyChengdu610059China Key Laboratory of Rhenium-Osmium Isotopic geochemistry Chinese Academy of Geological SciencesBeijing100037China

The Mg isotopic compositions of siliciclastic components(δ^(26)Mg_(sili))of sediments and sedimentary rocks have been commonly used to constrain the intensity of continental weathering,based on observations of,(1)an upward enrichment of26Mg in modern weathering profiles,(2)preferential uptake of26Mg in soil clays,and(3)general positive correlations between weathering intensities andδ^(26)Mg_(sili)***,not all weathering profiles display an upward increase ofδ^(26)Mg_(sili),and not all soil clays enrich in26Mg,complicating the interpretations ofδ^(26)Mg_(sili)data of sediments and sedimentary *** further explore the controls ofδ^(26)Mg_(sili)of sediments and sedimentary rocks,here we measuredδ^(26)Mg_(sili),mineralogical compositions and major element compositions of deep sea sediments from South China Sea(SCS)and carbonate rock samples from two late Paleozoic sections in South *** samples show decreasing trends of both normalized Mg concentration(Mgnorm)andδ^(26)Mg_(sili)values with the increase of weathering intensity,while SCS sediments samples do not show any correlation between Mgnormorδ^(26)Mg_(sili)values and weathering intensity.A three-stages weathering model is developed to explain the observed Mgnorm andδ^(26)Mg_(sili)*** the new model,weathering can be divided into three stages,(1)the preliminary weathering stage characterized by dissolution of primary minerals and formation of secondary clay minerals in saprolite,(2)the transitional stage with massive vermiculite and chlorite formation on the bottom of soil,and(3)the advanced stage showing dissolution of vermiculite and chlorite in the top of *** new model explains anδ^(26)Mg_(sili)increase and Mgnormdecrease with an increase weathering intensity in preliminary weathering stage and decrease of Mgnormandδ^(26)Mg_(sili)with increase weathering intensity in advanced weathering *** revised weathering model warrants the application of Mg isotope in the study of contin

关键词： Clay mineral Chemical weathering CIA Soil Weathering model

A wideband,high-resolution vector spectrum analyzer for integrated photonics

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2024年第4期13卷 760-771页

作者： Yi-Han Luo baoqi Shi Wei sun Ruiyang Chen Sanli Huang Zhongkai Wang Jinbao Long Chen Shen Zhichao Ye Hairun guo Junqiu Liu International Quantum Academy 518048 ShenzhenChina. Shenzhen Institute for Quantum Science and Engineering Southern University of Science and Technology518055 ShenzhenChina. Department of Optics and Optical Engineering University of Science and Technology of China230026 HefeiChina. Hefei National Laboratory University of Science and Technology of China230088 HefeiChina. Qaleido Photonics 518048 ShenzhenChina. Key Laboratory of Specialty Fiber Optics and Optical Access Networks Shanghai University200444 ShanghaiChina

The analysis of optical spectra—emission or absorption—has been arguably the most powerful approach for discovering and understanding *** invention and development of many kinds of spectrometers have equipped us with versatile yet ultra-sensitive diagnostic tools for trace gas detection,isotope analysis,and resolving hyperfine structures of atoms and *** proliferating data and information,urgent and demanding requirements have been placed today on spectrum analysis with ever-increasing spectral bandwidth and frequency *** requirements are especially stringent for broadband laser sources that carry massive information and for dispersive devices used in information processing *** addition,spectrum analyzers are expected to probe the device’s phase response where extra information is *** we demonstrate a novel vector spectrum analyzer(VSA)that is capable of characterizing passive devices and active laser sources in one *** a dual-mode VSA can measure loss,phase response,and dispersion properties of passive *** also can coherently map a broadband laser spectrum into the RF *** VSA features a bandwidth of 55.1 THz(1260–1640 nm),a frequency resolution of 471 kHz,and a dynamic range of 56 ***,our fiber-based VSA is compact and *** requires neither high-speed modulators and photodetectors nor any active feedback ***,we employ our VSA for applications including characterization of integrated dispersive waveguides,mapping frequency comb spectra,and coherent light detection and ranging(LiDAR).Our VSA presents an innovative approach for device analysis and laser spectroscopy,and can play a critical role in future photonic systems and applications for sensing,communication,imaging,and quantum information processing.

关键词： spectrum resolution coherent

Frequency-comb-linearized, widely tunable lasers for coherent ranging

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

Photonics Research 2024年第4期12卷 663-681页

作者： baoqi SHI YI-HAN LUO WEI sun YUE HU JINBAO LONg XUE BAI ANTINg WANg JUNQIU LIU Department of Optics and Optical Engineering University of Science and Technology of ChinaHefei 230026China International Quantum Academy Shenzhen 518048China Shenzhen Institute for Quantum Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Hefei National Laboratory University of Science and Technology of ChinaHefei 230088China

Tunable lasers,with the ability to continuously vary their emission wavelengths,have found widespread applications across various fields such as biomedical imaging,coherent ranging,optical communications,and *** these applications,a wide chirp range is advantageous for large spectral coverage and high frequency ***,the frequency accuracy and precision also depend critically on the chirp linearity of the *** extensive efforts have been made on the development of many kinds of frequency-agile,widely tunable,narrow-linewidth lasers,wideband yet precise methods to characterize and linearize laser chirp dynamics are also *** we present an approach to characterize laser chirp dynamics using an optical frequency *** instantaneous laser frequency is tracked over terahertz bandwidth at 1 MHz *** this approach we calibrate the chirp performance of 12 tunable lasers from Toptica,Santec,New Focus,EXFO,and NKT that are commonly used in fiber optics and integrated *** addition,with acquired knowledge of laser chirp dynamics,we demonstrate a simple frequency-linearization scheme that enables coherent ranging without any optical or electronic linearization *** approach not only presents novel wideband,highresolution laser spectroscopy,but is also critical for sensing applications with ever-increasing requirements on performance.

关键词： tunable Focus coherent

基于gNSS载波相位的守时系统远程性能评估方法研究

在线全文

学校读者我要写书评

暂无评论

大地测量与地球动力学 2024年第3期44卷 251-256页

作者：施敏琳张向波赵当丽孙保琪武建锋中国科学院国家授时中心西安市710600 中国科学院大学北京市100049 中国科学院时间频率基准重点实验室西安市710600

为测试在建守时系统性能,提出基于gNSS载波相位的远程评估方法,并开展实验验证。以国家标准时间UTC(NTSC)为参考,基于西安和北京地区4个测站连续15 d的gNSS观测数据,分别采用PPP和载波相位共视(PCV)法解算得到待测守时系统相对UTC(NTSC... 详细信息

为测试在建守时系统性能,提出基于gNSS载波相位的远程评估方法,并开展实验验证。以国家标准时间UTC(NTSC)为参考,基于西安和北京地区4个测站连续15 d的gNSS观测数据,分别采用PPP和载波相位共视(PCV)法解算得到待测守时系统相对UTC(NTSC)的时间偏差,然后对待测守时系统的相对频率偏差、频率稳定度等关键指标进行分析。结果表明,PCV和PPP时间传递链路的系统误差小,时间传递准确度高,采用PCV和PPP时间传递可准确测量相距较远的守时系统的频率稳定度、相对频率偏差等特性,可为下一步国产守时系统性能远程测试打下坚实基础。

关键词： gNSS 精密单点定位载波相位共视频率稳定度相对频率偏差

Spin accommodation and reactivity of nickel clusters with oxygen:Aromatic and magnetic metalloxocube Ni_(13)O_(8)^(±)

在线全文

学校读者我要写书评

暂无评论

Nano Research 2021年第12期14卷 4822-4827页

作者： Lijun geng baoqi Yin Hanyu Zhang Zhen-Dong sun Zhixun Luo School of Physics Shandong UniversityJinan250100China Beijing National Laboratory for Molecular Sciences(BNLMS) State Key Laboratory for Structural Chemistry of Unstable and Stable SpeciesInstitute of ChemistryChinese Academy of SciencesBeijing100190China School of Physics and Electrical Engineering Kashi UniversityKashgar844006China University of Chinese Academy of Sciences Beijing100049China

Due to challenges in preparing pure metal clusters and in controlling reactions,the oxides produced by metal clusters reacting with oxygen are often different from traditional ion-molecule products in the gas phase and their reactivity pattern is also largely unveiled *** this work,utilizing a customized Re-TOFMS having a home-made cluster source and a flow tube reactor,we have observed the gaseous reactions of Nin±clusters with oxygen and found magic clusters of Ni_(13)O_(8)±that dominate the mass *** quantum chemistry calculations,we find that both Ni_(13)O_(8)−and Ni_(13)O_(8)+clusters bear a regular cubic structure with 8 oxygen anchoring the eight angles,however,they have rather different spin *** Ni_(13)O_(8)−clusters have 15 unpaired spin-up electrons exhibiting cubic aromaticity and decent ferromagnetism,while the Ni_(13)O_(8)+clusters take a lower-spin ground state(11 unpaired electrons),with spin-down population on the central Ni atom pertaining to *** is a class of metalloxocube clusters that hold properties of aromaticity and ferromagnetism/ferrimagnetism charcterized by a few spin electrons,which embodies the bonding nature of superatomic compounds and enables to develop cluster-genetic materials of multi-functionality.

关键词： metalloxocube superatomic compounds aromaticity ferromagnetism cluster materials

奥马珠单抗治疗儿童日光性荨麻疹一例并文献复习

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

中国麻风皮肤病杂志 2024年第2期40卷 116-117页

作者：曲芃杜东红杨宝琦山东第一医科大学附属皮肤病医院山东济南250022 山东省皮肤病性病防治研究所山东济南250022

日光性荨麻疹传统治疗方案主要有抗组胺药物、光硬化、白三烯受体拮抗剂,然而有很多患者对传统治疗方案反应不佳。既往报道奥马珠单抗治疗儿童日光性荨麻疹有效,本文报道奥马珠单抗治疗儿童日光性荨麻疹一例,并进行文献复习。患者为一例... 详细信息

日光性荨麻疹传统治疗方案主要有抗组胺药物、光硬化、白三烯受体拮抗剂,然而有很多患者对传统治疗方案反应不佳。既往报道奥马珠单抗治疗儿童日光性荨麻疹有效,本文报道奥马珠单抗治疗儿童日光性荨麻疹一例,并进行文献复习。患者为一例3岁男性患儿,日晒后全身红斑、风团伴瘙痒1年。给予患者奥马珠单抗150 mg皮下注射,患者好转出院。随访22个月,患者目前维持奥马珠单抗治疗中,皮疹无复发。

关键词：日光性荨麻疹奥马珠单抗

多烯磷脂酰胆碱注射液治疗酒精性肝病的系统评价与Meta分析

在线全文

学校读者我要写书评

暂无评论

中国药师 2024年第1期27卷 135-144页

作者：曾保起章萌刘晓智盛凤孙凤天津市第五中心医院(北京大学滨海医院)中心实验室天津300450 北京大学公共卫生学院流行病与卫生统计学系北京100191 重大疾病流行病学教育部重点实验室(北京大学) 北京100191

目的系统评价多烯磷脂酰胆碱注射液治疗酒精性肝病(ALD)的有效性和安全性。方法计算机检索PubMed、Embase、the Cochrane Library、***、中国知网、SinoMed、维普和万方数据库,搜集有关多烯磷脂酰胆碱注射液治疗ALD的随机对照临床试验(R... 详细信息

目的系统评价多烯磷脂酰胆碱注射液治疗酒精性肝病(ALD)的有效性和安全性。方法计算机检索PubMed、Embase、the Cochrane Library、***、中国知网、SinoMed、维普和万方数据库,搜集有关多烯磷脂酰胆碱注射液治疗ALD的随机对照临床试验(RCT),检索时限均为建库至2022年12月31日。由2名研究者独立筛选文献、提取资料并评价纳入研究的偏倚风险后,使用Stata 17.0软件进行随机效应模型的Meta分析。结果最终纳入10个RCT,包含809例患者。Meta分析结果显示,多烯磷脂酰胆碱注射液组的有效率高于对照组[RR=1.12,95%CI(1.04,1.20),P=0.0038];与对照组相比,多烯磷脂酰胆碱注射液可以降低丙氨酸氨基转移酶(ALT)水平[MD=-18.92 U/L,95%CI(-27.75,-10.09),PggT)水平[MD=-48.93 U/L,95%CI(-54.64,-43.21),PggT)的水平,不良反应较少。受纳入研究数量和质量的限制,上述结论尚需开展更多高质量研究予以验证。

关键词：多烯磷脂酰胆碱酒精性肝病有效性 Meta分析随机对照试验

基于知识图谱与PACS的CBL教学法在临床眼科教学实践中的效果

在线全文

学校读者我要写书评

暂无评论

中国卫生产业 2024年第9期21卷 30-32,36页

作者：钟莹莹孙宝琪朱艳朱玉广山东第二医科大学附属医院眼科中心山东潍坊261041

目的分析基于知识图谱与影像存储与传输系统(Picture Archiving and Communication System,PACS)的案例教学法(Case-based Learning,CBL)在临床眼科教学实践中的效果。方法选择2023年4月—2024年1月在山东第二医科大学附属医院实习的49... 详细信息

目的分析基于知识图谱与影像存储与传输系统(Picture Archiving and Communication System,PACS)的案例教学法(Case-based Learning,CBL)在临床眼科教学实践中的效果。方法选择2023年4月—2024年1月在山东第二医科大学附属医院实习的49名学生为研究对象,按照不同教学方法分为对照组(n=24,予以传统教学法)、研究组(n=25,予以基于知识图谱与PACS的CBL教学法)。对比两组综合测评成绩、临床决策能力、临床安全思维能力。结果教学后,研究组理论考核成绩为(92.24±2.79)分、实践考核成绩为(91.72±2.53)分,高于对照组的(81.71±2.25)分、(78.80±2.69)分,差异有统计学意义(t=14.506、17.325,P均<0.05)。教学后,研究组临床决策能力与临床安全思维能力评分均高于对照组,差异有统计学意义(P均<0.05)。结论基于知识图谱与PACS的CBL教学法可改善学生综合测评成绩,并提升临床决策能力与临床安全思维能力。

关键词：案例教学法眼科教学影像存储与传输系统知识图谱

全关节镜与切开手术治疗肩袖撕裂疗效比较的系统综述与Meta分析

维普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

中华肩肘外科电子杂志 2024年第3期12卷 238-245页

作者：郁凯曾保起杨剑杨杰张殿英孙凤中国航天科工集团七三一医院创伤救治中心北京100074 北京大学公共卫生学院流行病与卫生统计学系 100191 北京大学滨海医院骨科天津300450 北京大学人民医院创伤骨科 100044

目的采用Meta分析的方法比较全关节镜与切开修复治疗肩袖撕裂的有效性和安全性。方法系统检索Embase、Medline、Cochrane Library、***、SinoMed、中国知网、维普、万方数据库发表的全关节镜与小切口或开放手术比较治疗肩袖撕裂的随机... 详细信息

目的采用Meta分析的方法比较全关节镜与切开修复治疗肩袖撕裂的有效性和安全性。方法系统检索Embase、Medline、Cochrane Library、***、SinoMed、中国知网、维普、万方数据库发表的全关节镜与小切口或开放手术比较治疗肩袖撕裂的随机对照临床试验。检索日期均从数据库开始日期至2023年4月。采用Cochrane风险评估工具对纳入文献进行偏倚风险评价。采用Stata14.0进行Meta分析。比较组间术后肩关节功能评分、肩关节疼痛评分、肩关节活动范围(前屈与外旋度数)、手术时间、并发症(再撕裂与关节僵硬)的差异。结果共纳入9篇文献,共1018例患者,其中全关节镜512例、切开修复506例。Meta分析结果显示,两组的肩关节功能评分(SMD=-0.02,95%CI:-0.19~0.15,P=0.81)、肩关节疼痛评分(SMD=-0.02,95%CI:-0.18~0.14,P=0.84)、前屈活动度(MD=1.29,95%CI:-0.71~3.30,P=0.21)、外旋活动度(MD=-0.31,95%CI:-3.32~2.69,P=0.84)、再撕裂率(RR=1.22,95%CI:0.88~1.68,P=0.23)、关节僵硬率(RR=0.89,95%CI:0.48~1.64,P=0.71)等结局指标差异均无统计学意义。全关节镜组的手术时间长于切开修复组(MD=12.12,95%CI:2.03~22.21,P=0.02)。结论全关节镜与切开手术相比治疗肩袖撕裂的临床效果相近。

关键词：关节镜肩袖撕裂小切口 Meta分析