检索结果-南通市图书馆

Applicability of high-temperature cooling systems in different European countries from the view of the condensation risk

在线全文

学校读者我要写书评

暂无评论

Building Simulation 2021年第5期14卷 1453-1466页

作者： vladim.r Zmrhal Martin Bartak Czech Technical University in Prague Faculty of Mechanical EngineeringDepartment of Environmental Engineering Technicka 416000 Prague 6Czech Republic

Due to the different approaches in determining the ventilation airflow rate per person for workspaces,where high-temperature air conditioning systems are used for air conditioning,problems with the condensation of water vapour on the cold surfaces of the system can *** article analyses the risk of condensation in various European cities using the available climatic *** with cooling ceilings and cooling beams with a ventilation device operating in parallel are taken into *** ventilation airflow rates per person were *** the example of a room equipped with high-temperature cooling,an energy simulation calculation is performed,which includes a ventilation and air-conditioning system with the possibility of capacity *** is clear from the results that the condensation of water vapour can be prevented by technical measures at the cost of reducing the cooling capacity,which can affect the achievement of the thermal comfort of those *** the end,suitable solutions are discussed,which should already be adopted at the time the device is designed so that the risk of condensation is not a major obstacle in the operation of these energy-efficient *** irreplaceable role in the operation of high-temperature cooling systems is played by a measurement and control system with a suitable algorithm to prevent condensation.

关键词： ventilation air-conditioning cooled ceilings chilled beams low energy cooling risk of condensation

Determination of the sensible heat effectiveness and pressure loss of a rotary regenerative heat exchanger using CFD

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Building Simulation 2023年第6期16卷 869-887页

作者： vladim.r Zmrhal Petr Zelenský Jindřich Boháč Martin Barták Miroslav kučera roman Vavřička Faculty of Mechanical Engineering Department of Environmental EngineeringCzech Technical University in PragueTechnická416000Prague 6Czech Republic

The paper presents a new method to determine the sensible effectiveness and pressure loss of rotary regenerative heat exchangers using computational fluid dynamics(CFD).It is based on CFD simulations of a single thermal wheel microchannel with a small cross-sectional area and thin walls,with cyclic inlet and outlet boundary *** unique measurement set-ups were designed and built for the experimental measurement of the heat exchanger *** different types of thermal wheels were manufactured,measured,and simulated in ANSYS *** wheels achieve an effectiveness greater than 73%under certain(air flow)conditions,which is the minimum effectiveness required by Ecodesign(in the EU).For the examined exchangers,the effectiveness ranges from 66.5%to 83.3%,depending on the boundary conditions and geometric parameters of the *** highest sensible effectiveness is achieved by heat exchangers with the largest heat exchange surface Ac;on the other hand,these wheels have the largest pressure *** paper discusses the use of a simplifiedε-NTU correlation model for the HVAC systems(typically C*=1).The correlation model and CFD results were compared and found to be different from each *** results of the CFD simulation were compared with measurements to prove that the proposed simulation method can predict the behaviour of the real heat exchanger as a *** was demonstrated that the sensible effectiveness and pressure loss of the rotary heat exchanger predicted by the CFD simulations correspond well to the measured values within the measurement uncertainty±1.3%.The proposed method can be used for the comparison of different rotary regenerative heat exchangers before their manufacturing and for verification that they meet the EU Ecodesign requirements set by the current *** reduces the cost of the initial optimisation and testing of new designs.

关键词： rotary heat exchanger heat wheel microchannel heat recovery sensible effectiveness pressureloss computer fluid dynamics experiment

Possibilities of GPS kinematic Measurements for Geological Survey in East Slovakia

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Geo-Spatial Information Science 2002年第4期5卷 21-25页

作者： vladim.r Sedlák Viera Huríková Sona Molíková Department of Geodesy and Geophysics The Technical University of Kosice Park Komenskeho 19 SK-043 84 Kosice Slovakia

This paper deals with transformation procedures for observed GPS data from the world geodetic system WGS84 into the national geodetic grid datum SUTCN （system of united trigonometric cadaster network） and Baa（the Baltic Sea after adjustment）.Transformation from WGS84 into SUTCN is performed most frequently by means of the 7element Helmert transformation with three identical *** network was adjusted by two ways.

关键词： kinematic GPS technology 3D coordinate transformations free adjustment adjustment with constraints

Entropy—A Universal Concept in Sciences

在线全文

学校读者我要写书评

暂无评论

Natural Science 2014年第7期6卷 552-564页

作者： vladim.r Majerník Mathematical Institute Slovak Academy of Sciences Bratislava Slovakia

Entropy represents a universal concept in science suitable for quantifying the uncertainty of a series of random events. We define and describe this notion in an appropriate manner for physicists. We start with a brief recapitulation of the basic concept of the theory probability being useful for the determination of the concept of entropy. The history of how this concept came into its to-day exact form is sketched. We show that the Shannon entropy represents the most adequate measure of the probabilistic uncertainty of a random object. Though the notion of entropy has been introduced in classical thermodynamics as a thermodynamic state variable it relies on concepts studied in the theory of probability and mathematical statistics. We point out that whole formalisms of statistical mechanics can be rewritten in terms of Shannon entropy. The notion “entropy” is differently understood in various science disciplines: in classical physics it represents the thermodynamical state variable;in communication theory it represents the efficiency of transmission of communication;in the theory of general systems the magnitude of the configurational order;in ecology the measure for bio-diversity;in statistics the degree of disorder, etc. All these notions can be mapped on the general mathematical concept of entropy. By means of entropy, the configurational order of complex systems can be exactly quantified. Besides the Shannon entropy, there exists a class of Shannon-like entropies which converge, under certain circumstances, toward Shannon entropy. The Shannon-like entropy is sometimes easier to handle mathematically then Shannon entropy. One of the important Shannon-like entropy is well-known Tsallis entropy. The application of the Shannon and Shannon-like entropies in science is really versatile. Besides the mentioned statistical physics, they play a fundamental role in the quantum information, communication theory, in the description of disorder, etc.

关键词： Probability Uncertainty Shannon Entropy Shannon-Like Entropies

ELECTrIC SPArk SENSITIVITY OF POLYNITrO COMPOUNDS: A COMPArISON OF SOME AUTHOrS′ rESULTS

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

含能材料 1998年第3期 23-27页

作者： Svatopluk ZEMAN * Pavel VALENTA ** vladim.r ZEMAN * Jan JAkUBkO ** Zdeněk kAMENSk Y ′ *** ( * Department of Theory and Technology of Explosives,University of Pardubice, CZ 532 10 Pardubice,the Czech republic)

测定了１５种多硝基化合物的静电火花感度并与文献值进行了对比。对同一样品来说不同作者得到的５０％发火概率的ＥＥＳ值不尽相同，其主要原因是不同作者所采用的静电火花试验规范不同。但是本实验值与文献值存在着线性关系。

关键词： 50%发火概率多硝基化合物静电火花感度

Natural orifice transluminal endoscopic surgeryvs laparoscopic ovariectomy:Complications and inflammatory response

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2012年第27期18卷 3558-3564页

作者： Jan Martínek Ondej ryska Tereza Filípková radek Dolezel Stefan Juhas Jan Motlík Monika Holubová vladim.r Nosek Barbora rotnáglová Miroslav Zavoral Miroslav ryska Department of Internal Medicine 1st Faculty of MedicineUniversity Military Hospital16000 PragueCharles UniversityCzech Republic Department of Surgery 2nd Faculty of MedicineUniversity Military HospitalCharles University16000 PragueCzech Republic Department of Surgery Domazlice Hospital34401 DomazliceCzech Republic Institute of Animal Physiology and Genetics Academy of Sciences27721 LibechovCzech Republic Department of Gastroenterology Jablonec Hospital46601 Jablonec nad NisouCzech Republic

AIM:To compare natural orifice transluminal endoscopic surgery (NOTES) vs standard laparoscopic ovariectomy in mini pigs with respect to technical aspects,complications and parameters of systemic inflammatory ***:This was a randomized,experimental,survival *** female mini pigs underwent NOTES transgastric ovariectomy (NOTES group) and ten female mini pigs underwent laparoscopic ovariectomy (LAP group).A "percutaneous endoscopic gastrostomy" approach with guidewire and sphincterotome was used for gastrotomy *** ovary was resected using standard biopsy forceps and a *** access site was closed using a "kING" closure with a single endoloop and several *** the laparoscopic group,a three-port laparoscopy and an ovariectomy were performed with the use of standard laparoscopic devices.C-reactive protein (CrP),white blood count and interleukin (IL)-6 plasma levels were used as indicators of systemic inflammatory *** animals were euthanized 28 d after ***:All animals survived without *** mean procedure time was 41.3 min ± 17.6 min (NOTES group) and 25.7 min ± 5.25 min (LAP group,P rtem examinations demonstrated that 50% and 70% of animals were free of any complications in the NOTES and LAP groups,*** remaining animals developed minor complications (adhesions) in a comparable frequency between the two *** the NOTES group,one animal developed a small intramural gastric abscess close to the gastrotomy site.A minor serous exudate that was present in 50% and 40% of the animals in the NOTES and laparoscopy groups,respectively,was not considered a *** both groups CrP levels increased significantly on the 2nd and 7th postoperative days (POD) and returned to normal after 28 *** POD 2,an increase of CrP level was significantly higher in the NOTES group compared to the LAP *** of IL-6 did not differ from baseline values in either of the groups postoperatively.

关键词： Natural orifice transluminal endoscopic sur-gery Laparoscopy Ovariectomy Systemic inflammatoryresponse

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

捷克和斯洛伐克的地震危险性

防灾减灾工程学报 1995年第S1期 42-43页

作者： vladim.r Schenk

1 地震危险性评定历史从1973年捷克斯洛伐克的建筑规范(?)SN73007 b就可看出地震危险性评定的初端。1978年为核电站选址,进行了地震危险性研究。通过结合Cornell的SErIAL程序算法的统计方法而提出的抗震设计计算中应用了这些地震危险性... 详细信息

1 地震危险性评定历史从1973年捷克斯洛伐克的建筑规范(?)SN73007 b就可看出地震危险性评定的初端。1978年为核电站选址,进行了地震危险性研究。通过结合Cornell的SErIAL程序算法的统计方法而提出的抗震设计计算中应用了这些地震危险性评定。SErIAL程序可考虑现有的地震资料、场地条件和局部衰减特征(Schenk et al..1981,Schenkouáet al..1981)。EQrISk程序用于在一给定区域,地震危险值的初步评定(McGuire,1976)。提出了一种新的确定最大预期强震效应的方法(Schonk,1984;Schenk and Mcmtlik1985),编制了修正的捷克斯洛伐克地震区划图(kárnik,et al.,1988)。

关键词：地震危险性核电站统计方法核电厂发电厂地震构造大地构造斯洛伐克地震活动区捷克

Nanoscale architecture of ceria-based model catalysts: Pt-Co nanostructures on well-ordered CeO_(2)(111) thin films

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Catalysis 2020年第6期41卷 985-997页

作者： Yaroslava Lykhach TomásSkála Armin Neitzel Nataliya Tsud klára Beranová kevin CPrince vladim.r Matolín Jorg Libuda Interface research and Catalysis Erlangen Catalysis Resource CenterFriedrich-Alexander-Universit?t Erlangen-NürnbergEgerlandstrasse 391058 ErlangenGermany Charles University Faculty of Mathematics and PhysicsDepartment of Surface and Plasma ScienceV Hole?ovi?kách 218000 PragueCzech Republic Elettra-Sincrotrone Trieste SCpA Strada Statale 14km 163.534149 Basovizza-TriesteItaly

We have prepared and characterized atomically well-defined model systems for ceria-supported Pt-Co core-shell catalysts. Pt@Co and Co@Pt core-shell nanostructures were grown on well-ordered CeO2(111) films on Cu(111) by physical vapour deposition of Pt and Co metals in ultrahigh vacuum and investigated by means of synchrotron radiation photoelectron spectroscopy and resonant photoemission spectroscopy. The deposition of Co onto CeO2(111) yields CoCeO2(111) solid solution at low Co coverage(0.5 ML), followed by the growth of metallic Co nanoparticles at higher Co coverages. Both Pt@Co and Co@Pt model structures are stable against sintering in the temperature range between 300 and 500 k. After annealing at 500 k, the Pt@Co nanostructure contains nearly pure Co-shell while the Pt-shell in the Co@Pt is partially covered by metallic Co. Above 550 k, the re-ordering in the near surface regions yields a subsurface Pt-Co alloy and Pt-rich shells in both Pt@Co and Co@Pt nanostructures. In the case of Co@Pt nanoparticles, the chemical ordering in the near surface region depends on the initial thickness of the deposited Pt-shell. Annealing of the Co@Pt nanostructures in the presence of O2 triggers the decomposition of Pt-Co alloy along with the oxidation of Co, regardless of the thickness of the initial Pt-shell. Progressive oxidation of Co coupled with adsorbate-induced Co segregation leads to the formation of thick CoO layers on the surfaces of the supported Co@Pt nanostructures. This process is accompanied by the disintegration of the CeO2(111) film and encapsulation of oxidized Co@Pt nanostructures by CeO2 upon annealing in O2 above 550 k. Notably, during oxidation and reduction cycles with O2 and H2 at different temperatures, the changes in the structure and chemical composition of supported Co@Pt nanostructures were driven mainly by oxidation while reduction treatments had little effect regardless of the initial thickness of the Pt-shell.

关键词： Core-shell nanoparticles Model catalyst Pt-Co Cerium oxide Chemical ordering Synchrotron radiation photoelectron spectroscopy

利用卫星遥感估算捷克共和国kruné Hory地区1972～1989年间针叶林覆盖变化

在线全文

学校读者我要写书评

暂无评论

人类环境杂志 1997年第3期26卷 154-162页

作者： Jonas Ard Nancy Lambert vladim.r Henzlík Barret N.rock 卢显富隆德大学美国新罕布什尔大学复杂系统研究中心森林生态室复杂系统研究中心

本文对位于捷克与德国边境受到严重污染的krusne Hory山区1972～1989年间森林破坏的范围、速率及其空间特性进行了研究。利用卫星遥感数据与数字地形数据相结合,对森林破坏进行评估。结果表明:有50%的针叶林在这一时期消失;受影响地区... 详细信息

本文对位于捷克与德国边境受到严重污染的krusne Hory山区1972～1989年间森林破坏的范围、速率及其空间特性进行了研究。利用卫星遥感数据与数字地形数据相结合,对森林破坏进行评估。结果表明:有50%的针叶林在这一时期消失;受影响地区位于海拔600与1000m及坡向朝南和东南的坡地;位于SO_2和NO_x的强污染点源下风向地区的森林受到严重破坏。森林破坏与距离点源的远近间关系不明确。1989年依据针叶脱落,应用卫星遥感对森林损害的估算结果表明:现存的308km^2针叶林中,被划分为受轻度、中度及重度损害的森林分别为79%、17%及4%。

关键词：捷克卫星遥感针叶林覆盖污染