检索结果-南通市图书馆

Journal of Rare Earths 2006年第4期24卷 385-391页

作者： ludek jelinek Mikio Kumagai Nuclear Chemistry and Chemical Engineering Center Institute of Research and Innovation1201 Takada Kashiwa 277-0861 Chiba-prefecture Japan

Ce （Ⅳ） nitrato complexes were adsorbed on two anion exchangers based on polyvinyl pyridine （PVP） and quatemized PVP incorporated into porous silica matrix. The effect of nitric acid concentration （0.5～6 mol·L^-1） and temperature （278 ～318 K） on Ce（ Ⅳ ） sorption efficiency was investigated. Sorption increased with increasing nitric acid concentration, indicating that [Ce（NO3）6]^2- complex is the main adsorbed Ce（Ⅳ） species. Oxidation of sorbents by adsorbed Ce （ Ⅳ ） species resulting in Ce （ Ⅲ ） release to the solution was observed. Pyridine based anion exchangers exhibited higher oxidation stability compared to the commercial strong base anion exchanger. Ce（ Ⅳ ） reduction was temperature dependent and obeyed pseudo-first-order reaction kinetics. Column separation of Ce （ Ⅳ ） from La （ Ⅲ ） and Y （ Ⅲ ） was carried out from 6 mol·L^-1 nitric acid with PVP based anion exchanger. Reasonable Ce （Ⅳ） breakthrough capacity （0.7 mol·kg^-1 PVP） was achieved. No remarkable decrease of capacity was observed within 3 consequent runs. In contrast, Ce （Ⅲ） leakage due to reduction decreased and breakthrough capacity slightly increased. This effect was more pronounced with increasing temperature. Regeneration with 0.1 mol·L^- 1 nitric acid was successful （recovery 100% ± 4% ） and Ce solution of high purity （〉 99.97% ） with respect to La and Y content was gained.

关键词： ion exchange tetravalent cerium separation rare earths

Electro-Oxidation of Concentrated Ce(Ⅲ) at Carbon Felt Anode in Nitric Acid Media

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2006年第3期24卷 257-263页

作者： jelinek ludek Mikio Kumagai Nuclear Chemistry and Chemical Engineering Center Institute of Research and Innovation 1201 Takada Kashiwa 277-0861 Chiba-ken Japan

Electro-oxidation of Ce （ Ⅲ ） to Ce （ Ⅳ ） in parallel plate flow type electrolyzer divided with cation exchange membrane was carried out in nitric acid media at carbon felt anode under galvanostatic conditions. Carbon felt was used as an anode for its high specific surface area and high oxygen evolution overpotential. Pt coated Ti plates were used as cathode and anode current feeder. The oxidation of 1 mol· L^-1 Ce（ Ⅲ ） solution in 2 mol· L^- 1 HNO3 was proceeding with a high current efficiency （92%） until about 80% of Ce（ Ⅲ ） was oxidized. Then, oxygen evolution, accompanied by terminal voltage jump, took place, lowering current efficiency. Ce（ Ⅲ ） was oxidized up to 90% with current efficiency of 62%. In this mode, strong carbon felt anode oxidation was observed. The wear out of carbon felt was 46% in six consequent runs （6 h of operation）. After each run, carbon felt surface had to be renewed with slightly alkaline solution to remove carbon oxidation products and ensure regular operational conditions. When anode surface was blocked, oxygen evolution took place from the beginning of electrolysis due to higher actual current density. The wear out of carbon felt anode could be minimized by means of oxygen evolution prevention. In the case when electrolysis had been stopped before oxygen evolution started （at Ce（ Ⅳ ） conversion of about 80% ）, the wear out of anode was less than 2% during 6 consequent runs （4 h of operation）.

关键词： electrolyzer Ce oxidation carbon felt anode rare earths

Direct Spectroscopic Determination of Europium（ Ⅱ ） Concentration During Europium（ Ⅲ ） Electro-Reduction in Hydrochloric Acid Medium

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2007年第1期25卷 1-5页

作者： ludek jelinek Tsuyoshi Arai Wei Yuezhou Mikio Kumagai Institute of Research and Innovation （IRI） 1201 Takada Kashiwa 277-0861 Japan

UV-Vis spectroscopy was used to directly determine the concentration of Eu（ Ⅱ） during electroreduction of Eu （ Ⅲ ） in hydrochloric acid medium. Electroreduction was carried out in a flow type electrolyzer with glassy carbon cathode at the constant potential of - 800 mV vs. Ag/AgCl. The effects of oxygen and concentration of hydrochloric acid on the system were investigated. For 0.01 mol· L^-1 hydrochloric acid, calibration curves for Eu （Ⅱ） absorption bands at 248 and 320 nm were constructed. Molar absorption coefficients were estimated to be 2016 and 648 L· mol^-1·cm^-1, respectively. The absorbance strongly decreased with decrease in pH of the solution, whereas concentration of chloride had only a negligible effect.

关键词： Eu( Ⅱ ) electroreduction hydrochloric acid UV spectroscopy rare earths

Convergence over AI Governance Amid Differences

在线全文

学校读者我要写书评

暂无评论

China Today 2024年第4期73卷 58-61页

作者： THORSTEN jelinek Taihe Institute

As the EU passes the first AI law,the *** with bipartisanship,and China proactively advances the issue-based approach and advocates the Global AI Governance Initiative,will AI become“a force for good,ensuring safety,... 详细信息

关键词： fairness Convergence law

Convergence Despite Differences

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

Beijing Review 2024年第15期67卷 20-22页

作者： Thorsten jelinek Taihe Institute a Beijing-based nongovernmental think tank

This year is significant for establishing guardrails around artificial intelligence(AI),with major regions like the European Union,the United States and China converging over a risk-based regulatory approach,albeit with distinct *** trend reflects a broader trend toward digital sovereignty,with governments seeking increased control over their digital markets and technologies to ensure safety and security,while aiming to boost their AI competitiveness.

关键词： spite seeking establishing

Convergence over AI Governance Amid Differences

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

China Report ASEAN 2024年第4期9卷 46-47页

作者： Thorsten jelinek Taihe Institute

This year marks a significant year for establishing guardrails around artificial intelligence(AI),with major regions like the EU,the U.S.,and China converging over a risk-based regulatory approach,albeit with distinct *** trend reflects a broader trend towards digital sovereignty,with governments seeking increased control over their digital markets and technologies to ensure safety and security,while aiming to boost their AI competitiveness.

关键词： seeking establishing trend

Sniffing Bacteria with a Carbon-Dot Artificial Nose

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2021年第7期13卷 138-152页

作者： Nitzan Shauloff Ahiud Morag Karin Yaniv Seema Singh Ravit Malishev Ofra Paz-Tal Lior Rokach Raz jelinek Department of Chemistry Ben Gurion University of the Negev84105 Beer ShevaIsrael Department of Biotechnology Engineering Ben Gurion University of the Negev84105 Beer ShevaIsrael Chemistry Department Nuclear Research CenterNegevP.O.Box 900184190 Beer ShevaIsrael Department of Software and Information System Engineering Ben-Gurion University of the NegevBeer ShevaIsrael Ilse Katz Institute for Nanotechnology Ben Gurion University of the Negev84105 Beer ShevaIsrael

Continuous,real-time monitoring and identification of bacteria through detection of microbially emitted volatile molecules are highly sought albeit elusive *** introduce an artificial nose for sensing and distinguishing vapor molecules,based upon recording the capacitance of interdigitated electrodes(IDEs)coated with carbon dots(C-dots)exhibiting different *** of the C-dot-IDEs to volatile molecules induced rapid capacitance changes that were intimately dependent upon the polarities of both gas molecules and the electrode-deposited *** deciphered the mechanism of capacitance transformations,specifically substitution of electrode-adsorbed water by gas molecules,with concomitant changes in capacitance related to both the polarity and dielectric constants of the vapor molecules *** C-dot-IDE gas sensor exhibited excellent selectivity,aided by application of machine learning *** capacitive C-dot-IDE sensor was employed to continuously monitor microbial proliferation,discriminating among bacteria through detection of distinctive“volatile compound fingerprint”for each bacterial *** C-dot-IDE platform is robust,reusable,readily assembled from inexpensive building blocks and constitutes a versatile and powerful vehicle for gas sensing in general,bacterial monitoring in particular.

关键词： Carbon dots Bacterial detection Bacterially emitted volatile molecules Capacitive gas sensors Gas polarity

在线全文

学校读者我要写书评

暂无评论

Hen Sie zu!

德语学习 2004年第6期 8-13页

作者： Elfriede jelinek

Das Hoeren kommt einem fiber die Lippen wie em verbotenes Wort, aber man kann es nicht erschrocken zurticknehmen. Es liegt auf dem Tisch und wird geschnitten. Es blutet nicht. Es verschwindet nicht. Es ergibt ein tadelloses Bild, abet eben ein unsichtbares, und zwar fiir jeden, auch fuer den, der sehen kann. Fuer den, der hoeren kann, macht das Bild eine hoefliche Anfrage,

关键词：书刊文摘文学欣赏德语注释读物

Unusual radiologic presentations of malignant peritoneal mesothelioma

在线全文

学校读者我要写书评

暂无评论

World Journal of Radiology 2020年第12期12卷 316-326页

作者： Paul Hendrick Sugarbaker James S jelinek Center for Gastrointestinal Malignancies Program in Peritoneal Surface OncologyMedStar Washington Hospital CenterWashingtonDC 20010United States Department of Radiology MedStar Washington Hospital CenterWashingtonDC 20010United States

BACKGROUND Malignant peritoneal mesothelioma is an unusual disease process characterized radiologically by ascites and infiltration of the peritoneum by multiple small tumor *** parietal and visceral peritoneum are involved by the multiple malignant tumor *** tomography(CT)has been used to identify the anatomic pathology induced by the progression of this malignant *** To identify and then describe unusual CT images in patients with malignant peritoneal *** of these unusual radiologic findings can cause the radiologist to be suspicious of this rare malignant *** In 100 patients who were to undergo definitive treatment of malignant peritoneal mesothelioma,the findings on preoperative CT scans were *** of these changes were repeatedly noted on the CT *** pathologic CT images were less *** unusual radiologic presentations were specially studied in this *** Eight unusual radiologic presentations of malignant peritoneal mesothelioma were selected for *** unusual findings included a mass occurring within a Spigelian hernia,infiltration of the splenic parenchyma by spherical mesothelioma masses,infiltration of the lower mediastinum by tumor,a mesothelioma mass within a left inguinal canal,enlarged cardiophrenic angle lymph nodes,pleural plaques associated with the progression of malignant peritoneal mesothelioma,splenic notches caused by disease surrounding the spleen,and a mass greater than 5 cm associated with the proximal jejunum and directly adjacent to the anatomic location of the Treitz *** There are unusual radiologic presentations of malignant peritoneal mesothelioma that are important to recognize in order to accurately diagnose this disease by CT.

关键词： Costophrenic angle lymph nodes Pleural plaques Inguinal mass Inguinal hernia mass Splenic notches Concerning computed tomography features

The search for roAp stars: null results and new candidates from Strmgren-Crawford photometry

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

Research in Astronomy and Astrophysics 2018年第11期18卷 43-54页

作者： Ernst Paunzen Gerald Handler Katerina Honkova Jakub Jurysek Martin Masek Marek Drozdz Jan Janik Waldemar Ogtoza Lars Hermansson Mats Johansson Martin jelinek Marek Skarka Miloslav Zejda Department of Theoretical Physics and Astrophysics Masaryk UniversityKotlarska 2CZ-61137Czech Republic Nicolaus Copernicus Astronomical Center Bartycka 1800-716WarsawPoland Variable Star and Exoplanet Section of Czech Astronomical Society Vsetinska 941/78CZ-75701Valasske MeziriciCzech Republic Institute of Physics The Czech Academy of SciencesNa Slovance 1999/2CZ-18221PrahaCzech Republic Mt.Suhora Observatory Pedagogical UniversityPodchorazych 230-084KrakowPoland Sandvretens Observatory Linnegatan 5A75332UppsalaSweden Astronomical Institute Czech Academy of Sciences(ASU CAS)OndrejovCzech Republic

The rapidly oscillating Ap(roAp) stars exhibit pulsational photometric and/or radial velocity variations on time scales of several minutes, which are essential to test current pulsation models as well as our assumptions of atmospheric structure characteristics. In addition, their chemical peculiarity makes them very interesting for probing stellar formation and evolution in the presence of a global magnetic field. To date, a limited number of only 61 roAp stars is known to show photometric variability. On the other hand, a literature survey yields 619 unique stars that have unsuccessfully been searched for variability of this kind. Str o¨mgren-Crawford uvbyβ photometry of stars from both subgroups was used to investigate whether there is a selection bias for the investigated stars. We also present new photometric measurements(202 hours on 59 different nights) of 55 roAp candidates. We did not detect any new roAp star. Although our detection limits are comparable to other surveys, we also did not find pulsations in the known roAp star HD 12098, which may be a consequence of temporal amplitude changes. On the other hand, we do find some evidence for photometric variability of beta CrB at its spectroscopically derived pulsation period. From the uvbyβ photometry we conclude that the blue border of the roAp instability strip appears observationally well defined, whereas the red border is rather poorly known and *** these boundaries, a total of 4646 candidates were identified which appear worth investigating for short-term pulsational variability.

关键词： stars: chemically peculiar stars: early-type stars: variables: general techniques: photometric