检索结果-南通市图书馆

Einstein’s Concept of Clock Synchronization Conflicts with the Second Relativity Postulate

Journal of Modern Physics 2024年第7期15卷 985-1000页

作者： steven d. deines donatech Corporation Inc. Fairfield Iowa USA

Einstein defined clock synchronization whenever photon pulses with timetags traverse a fixed distance between two clocks with equal time spans ineither direction. Using the second relativity postulate, he found clocksmounted on a rod uniformly moving parallel with the rod’s length cannot besynchronized, but clocks attached to a stationary rod can. He dismissed thisdiscrepancy by claiming simultaneity and clock synchronization were not commonbetween inertial frames, but this paper proves with both Galilean and Lorentztransformations that simultaneity and clock synchronization are preservedbetween inertial frames. His derivation means moving clocks can never besynchronized in a “resting” inertial frame. Ultraprecise atomic clocks intimekeeping labs daily contradict his results. No algebraic error occurred inEinstein’s derivations. The two cases of clocksattached to a rod reveal three major conflicts with the currentsecond postulate. The net velocity between a photon source and detector plusthe “universal” velocity c is mathematically equivalent toEinstein’s clock synchronization method. As the ultraprecise timekeepingcommunity daily synchronizes atomic clocks on the moving Earth withultraprecise time uncertainty well below Einstein’s lowest limit ofsynchronization, the theoretical resolution of the apparent conflict isaccomplished by expanding the second relativity postulate to incorporate thenet velocity between the photon source and detector with the emitted velocity c as components of the total velocity c. This means the magnitudeof the total photon velocity can exceed the speed limit (299792458 m/s) set by the standard velocity c. .

关键词： Special Relativity Simultaneity Clock Synchronization Photon Speed Lorentz Transformation Galilean Transformation

来源：

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

Combined flow-focus and self-assembly routes for the formation of lipid stabilized oil-shelled microbubbles

引用

Microsystems & Nanoengineering 2018年第1期4卷 466-473页

作者： Adam H.Churchman Victoria Mico Julia Gala de Pablo Sally A.Peyman steven Freear Stephen d.Evans School of Physics and Astronomy University of LeedsWoodhouse LaneLeeds LS29JTUK School of Electronic and Electrical Engineering University of LeedsWoodhouse LaneLeeds LS29JTUK

Lipid and polymer stabilized microbubbles are used in medicine as contrast agents for ultrasound imaging and are being developed for the delivery of water soluble drugs to diseased areas of the ***,many new therapeutics exhibit poor water solubility or stability,which has led to the requirement for the development of effective hydrophobic drug delivery *** study presents a new method to produce microbubbles coated with an oil layer capable of encapsulating hydrophobic drugs and suitable for targeted,triggered drug *** new method utilizes highly controllable flow-focusing microfluidics with lipid oil nanodroplets self-assembling and spreading at gas–aqueous *** layer inside microbubbles were produced with diameters of 2.4±0.3μm(s.d.,1.6μm)and at concentrations up to 10^(6) bubbles per *** mechanism of oil layer inside microbubble assembly and stability were characterized using methods including contact angle measurements,quartz crystal microbalance with dissipation monitoring and fluorescence resonance energy transfer imaging.

关键词： microbubbles microfluidics drug-delivery hydrophobic lipid-coated oil-shelled

来源：

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

Real-world emission factors for Caterpillar 797B heavy haulers during mining operations

引用

Particuology 2016年第5期14卷 22-30页

作者： Xiaoliang Wang Judith C. Chow steven d. Kohl Kevin E. Percy Allan H. Legge John G. Watson desert Research Institute 2215 Raggio Parkway Reno NV 895J2 USA Graduate Faculty University of Nevada Reno NV89503 USA The State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi'an 710075 China Wood Buffalo Environmental Association 330 Thickwood Boulevard Fort McMurray AB Canada 7DK 1 Y1 Biosphere Solutions 1610 1 lth Avenue N.W. Calgary AB Canada T2N IG9

Real-world fuel-based emission factors （EFs） from Caterpillar 797B diesel heavy haulers when used for oil sands mining operations were measured using an on-hoard portable emissions monitoring system. Average EFs （in g/kg fuel） for 16 separate tests on four trucks were 3150 ± 4 for CO2, 2.51 ± 1.30 for CH4, 10.28 ± 3.21 for CO, 0.61 ± 0.32 for non-methane hydrocarbons, 55.49 ± 9,75 for NOx （reported as NO2）, 0.70 ± 0.17 for PM2.s （mass of particles with aerodynamic diameter 〈2.5 μm）, and 0.34 ± 0.05 for black carbon （BC）. Ultrafine particle numbers averaged （4.7 ± 4.1 ） × 10^15 particleslkg fuel. Fuel-based EFs of NO, NO2, and particle numbers were higher during idling, whereas PM2.5 and BC EFs were higher during traveling without a load. A comparison of emissions with those reported by oil sands facilities showed large variations, both among the facilities and between the reported emissions and the real-world measurements.

关键词： Heavy hauler Emission Nonroad Portable emissions measurement system Mining Oil sands

来源：

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

deriving the magnetopause position from wide field-of-view soft X-ray imager simulation

引用

Science China Earth Sciences 2022年第8期65卷 1601-1611页

作者： Yihong GUO Tianran SUN Chi WANG steven SEMBAY Aerospace Information Research Institute Chinese Academy of SciencesBeijing100094China National Space Science Center Chinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100049China School of Physics and Astronomy University of LeicesterLeicesterLE17RHUK

Imaging techniques provide essential information in astronomical and space physics *** Soft X-ray Imager(SXI)will obtain images of the Earth’s magnetosphere via the solar wind charge exchange process in a global ***,it is a challenge to reconstruct its 3-d structures from the observed 2-d image(s).In this paper,a recently proposed method,Tangent Fitting Approach(TFA),is validated to reconstruct the large-scale magnetopause from a single X-ray image obtained by instrument *** is revealed that the large-scale magnetopause under a medium solar wind number density can be well reconstructed,although the locations of maximum X-ray photon counts are scattered in the image due to instrumental effects and diffusive sky *** solar wind number density leads to stronger signals and further leads to better reconstruction *** lower solar wind density,the X-ray maximum photon counts may not be identified from the SXI simulations,preprocessing of the images shall be considered before applying ***,the subsolar magnetopause can be well derived when the satellite is on the dayside orbits.

关键词： Soft X-ray Imager Magnetosphere SMILE TFA

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

模拟实验研究利用植被冠层光谱探测CO_2轻微泄漏点

引用

光谱学与光谱分析 2015年第10期35卷 2781-2786页

作者：蒋金豹何汝艳 Michael d steven 胡卿杨中国矿业大学(北京)地测学院北京100083 School of Geography University of Nottingham

温室气体（CO2）过量排放可以导致全球气候变暖,而碳捕捉与储存（carbon capture and storage,CCS）技术是一种减少CO2气体排放的有效措施。但存储在地下的CO2有泄漏的风险,如何快速监测CO2轻微泄漏点是一个值得研究的问题。该文通过野... 详细信息

温室气体（CO2）过量排放可以导致全球气候变暖,而碳捕捉与储存（carbon capture and storage,CCS）技术是一种减少CO2气体排放的有效措施。但存储在地下的CO2有泄漏的风险,如何快速监测CO2轻微泄漏点是一个值得研究的问题。该文通过野外模拟实验,研究草地和大豆在CO2轻微泄漏胁迫下的冠层光谱特征,构建CO2轻微泄漏点高光谱遥感探测模型。在2008年5月—9月于英国诺丁汉大学Sutton Bonington校区（52.8N,1.2W）进行了野外模拟实验。实验共设置16个小区,8个草地及8个大豆地,其中各有4个小区进行CO2泄漏胁迫。冠层光谱采用美国ASd光谱仪进行测量,草地测量了6次数据,大豆地测量了3次数据。实验结果表明,草地与大豆地的冠层光谱反射率在580~680nm波段范围内随CO2泄漏胁迫程度的增大而增大,且在整个试验期内都保持同样的规律,因此构建面积指数AREA（580~680nm）（光谱曲线在580~680nm波段范围内包围的面积）识别遭受CO2泄漏胁迫下的植被。通过J-M距离检验,发现该指数能够较好地识别出CO2轻微泄漏胁迫下center区与core区的草地,但对edge区草地的识别能力不足（J-M距离小于1.8）;该指数可以可靠且稳健地识别出遭受CO2轻微泄漏胁迫的大豆。该研究结果可为未来应用高光谱遥感探测CO2轻微泄漏点提供理论依据与方法支持。

关键词：冠层光谱 CO2泄漏胁迫地表植被识别模型

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Stellar interiors 2ed.

引用

丛书名： Astronomy and astrophysics library

2004年

作者： Carl J. Hansen steven d Kawaler Virginia Trimble

来源：畅想之星图书光盘版（南... 评论

在线全文

畅想之星图书光盘版（南通市图书馆镜像）

学校读者我要写书评

暂无评论

Current methods for the maturation of induced pluripotent stem cellderived cardiomyocytes

引用

World Journal of Stem Cells 2019年第1期11卷 33-43页

作者： Pranav Machiraju steven C Greenway departments of Pediatrics and Cardiac Sciences Alberta Children’s Hospital Research Institute Libin Cardiovascular Institute of Alberta Cumming School of MedicineUniversity of Calgary departments of Pediatrics Cardiac Sciences Biochemistry & Molecular Biology Alberta Children’s Hospital Research Institute Libin Cardiovascular Institute of Alberta Cumming School of Medicine University of Calgary

Induced pluripotent stem cells(iPSCs) were first generated by Yamanaka and colleagues over a decade ago. Since then, iPSCs have been successfully differentiated into many distinct cell types, enabling tissue-, disease-, and patientspecific in vitro modelling. Cardiovascular disease is the greatest cause of mortality worldwide but encompasses rarer disorders of conduction and myocardial function for which a cellular model of study is ideal. Although methods to differentiate iPSCs into beating cardiomyocytes(iPSC-CMs) have recently been adequately optimized and commercialized, the resulting cells remain largely immature with regards to their structure and function,demonstrating fetal gene expression, disorganized morphology, reliance on predominantly glycolytic metabolism and contractile characteristics that differ from those of adult cardiomyocytes. As such, disease modelling using iPSC-CMs may be inaccurate and of limited utility. However, this limitation is widely recognized, and numerous groups have made substantial progress in addressing this problem. This review highlights successful methods that have been developed for the maturation of human iPSC-CMs using small molecules,environmental manipulation and 3-dimensional(3 d) growth approaches.

关键词： Induced pluripotent stem cells Induced pluripotent stem cell-derived cardiomyocytes Regenerative medicine Stem cell biology Translational research

来源：

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

Contemporary indications for and outcomes of hepatic resection for neuroendocrine liver metastases

引用

World Journal of Gastrointestinal Surgery 2020年第4期12卷 159-170页

作者： steven d Scoville dimitrios Xourafas Aslam M Ejaz Allan Tsung Timothy Pawlik Jordan M Cloyd department of Surgery Division of Surgical Oncology at The Ohio State UniversityJames Cancer CenterColumbusOH 43210United States The Arthur G James Comprehensive Cancer Center and Solove Research Institute The Ohio State UniversityColumbusOH 43210United States department of Surgery Harvard Medical SchoolDepartment of SurgeryBrigham and Women's HospitalHarvard Medical SchoolBostonMA 02215United States department of Surgery The Ohio State UniversityColumbusOH 43210United States department of Surgery The Ohio State University Wexner Medical CenterColumbusOH 43210United States department of Surgery Division of Surgical OncologyThe Ohio State University Wexner Medical CenterColumbusOH 43210United States

BACKGROUNd Although surgical resection is associated with the best long-term outcomes for neuroendocrine liver metastases(NELM),the current indications for and outcomes of surgery for NELM from a population perspective are not well *** To determine the current indications for and outcomes of liver resection(LR)for NELM using a population-based *** A retrospective review of the 2014-2017 American College of Surgeons National Surgical Quality Improvement Program and targeted hepatectomy databases was performed to identify patients who underwent LR for *** characteristics and 30-d morbidity and mortality were *** Among 669 patients who underwent LR for NELM,the median age was 60(interquartile range:51-67)and 51%were *** the number of metastases resected ranged from 1 to 9,the most common(45%)number of tumors resected was *** majority(68%)of patients had a largest tumor size ofderwent partial hepatectomy(71%)while fewer underwent a right or left hepatectomy or *** majority of operations were open(82%)versus laparoscopic(17%)or robotic(1%).In addition,30%of patients underwent intraoperative ablation while 45%had another concomitant operation including cholecystectomy(28.8%),bowel resection(20.2%),or partial pancreatectomy(3.4%).Overall 30-d morbidity and mortality was 29%and 1.3%,*** multivariate analysis,American Society of Anesthesiologists class≥3[odds ratios(OR),OR=2.089,95%confidence intervals(CI):1.197-3.645],open approach(OR=1.867,95%CI:1.148-3.036),right hepatectomy(OR=1.618,95%CI:1.014-2.582),and prolonged operative time of>230 min(OR=1.731,95%CI:1.168-2.565)were associated with higher 30-d morbidity while intraoperative ablation and concomitant procedures were *** LR for NELM was performed with relatively low postoperative morbidity and *** procedures performed at the time of LR did not increase morbidity.

关键词： Carcinoid Neuroendocrine tumor Primary tumor resection Intraoperative ablation Cholecystectomy Small bowel resection

来源：

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

Long-term antifibrotic action of interferon-γ treatment in patients with chronic hepatitis B virus infection

引用

Hepatobiliary & Pancreatic diseases International 2011年第2期10卷 151-157页

作者： Peter R Mertens steven dooley department of Nephrology and Hypertension Otto-von-Guericke-University First Affiliated Hospital Zhejiang University School of Medicine Molecular Hepatology-Alcohol dependent diseases II. Medical Clinic Faculty of Medicine at MannheimUniversity of Heidelberg

BACKGROUNd:The first priority in treating fibrosis is to eliminate the causes that result in liver injury,e.g.,hepatitis B and C ***,in many liver diseases the cause is either unknown or *** present study was designed to investigate the long-term antifibrotic effect of interferon-gamma(IFN-γ)treatment in patients chronically infected with hepatitis B virus. METHOdS:A total of 42 patients,30 treated with IFN-γand 12 controls,were enrolled from an original clinical trial(Clin Gastroenterol Hepatol 2005;3:819.).Three serial liver biopsies that were obtained at the initiation and end of IFN-γtreatment as well as 4 to 6 years after treatment discontinuation were assessed according to the modified Chevallier scoring system. RESULTS:Twenty-five out of 30 IFN-γ-treated patients were followed up until 4 to 6 years after the treatment was stopped. However,all controls were excluded from follow-up due to death,loss and elevated virus level within 2 ***-five IFN-γ-treated patients had stable serum liver function and liver fibrosis indices without any further antiviral or anti-fibrotic *** inflammatory and fibrotic scores were found after nine months of IFN-γtreatment according to the modified Chevallier scoring system(inflammation:11.8±6.5 at the beginning of IFN-γtreatment vs.9.2±4.1 after 9 months, Pd a third serial liver biopsy 4 to 6 years after treatment discontinuation,and the fibrotic score was increased(14.2±8.3 vs.11.9±7.6 after 9 months, Pdemonstrate stable serum biochemical indices and quality of ***,they do not show a long-term benefit according to histological criteria. Given the limited sample size,long-term IFN-γtreatment regimens should be assessed in further

关键词： hepatic stellate cells hepatitis B virus liver fibrosis inflammation interferon-gamma

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

水浸胁迫下植被高光谱遥感识别模型对比分析

引用

光谱学与光谱分析 2013年第11期33卷 3106-3110页

作者：蒋金豹 Michael d steven 何汝艳蔡庆空中国矿业大学北京地球科学与测绘工程学院北京100083 School of Geography University of NottinghamNG7 2RDUK

随着全球气候变暖,我国洪涝灾害发生的频率及影响范围都不断增加。通过野外模拟试验,研究植被(玉米、甜菜)在水浸胁迫下的光谱变化特征,以构建高光谱遥感模型对水涝灾害范围进行监测。试验于2008年5月—8月在英国诺丁汉大学Sutton Bonin... 详细信息

随着全球气候变暖,我国洪涝灾害发生的频率及影响范围都不断增加。通过野外模拟试验,研究植被(玉米、甜菜)在水浸胁迫下的光谱变化特征,以构建高光谱遥感模型对水涝灾害范围进行监测。试验于2008年5月—8月在英国诺丁汉大学Sutton Bonington校区(52.8°N,1.2°W)进行,每周采集一次样本并在室内测量其光谱数据。试验结果表明植被光谱在550,800~1 300nm区域反射率都稍有降低,而在680nm区域反射率则略微增大。选取NdVI,SIPI,PRI,SRPI,GNdVI及R800*R550/R680共六个植被指数识别水浸胁迫下的植被,研究表明,指数SIPI与R800*R550/R680对水浸胁迫玉米比较敏感,而指数SIPI,PRI及R800*R550/R680对水浸胁迫甜菜比较敏感。为寻找最优的识别模型,计算对照与水浸胁迫植被指数之间的归一化均值距离并进行对比分析,发现植被指数R800*R550/R680的归一化均值距离在胁迫早期即大于其他指数的距离,说明该指数识别水浸胁迫植被的能力优于其他指数,且具有较强的敏感性与稳健性。因此,可以利用该指数快速地提取水浸面积,为救灾减灾决策提供信息支持。

关键词：光谱特征水浸胁迫植被识别模型对比分析归一化均值距离

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：