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排序方式: 共有253条查询结果,搜索用时 31 毫秒
231.
Gerhard Schall Erick Mendez Ernst Kruijff Eduardo Veas Sebastian Junghanns Bernhard Reitinger Dieter Schmalstieg 《Personal and Ubiquitous Computing》2009,13(4):281-291
In this paper, we present an Augmented Reality (AR) system for aiding field workers of utility companies in outdoor tasks
such as maintenance, planning or surveying of underground infrastructure. Our work addresses these issues using spatial interaction
and visualization techniques for mobile AR applications and as well as for a new mobile device design. We also present results
from evaluations of the prototype application for underground infrastructure spanning various user groups. Our application
has been driven by feedback from industrial collaborators in the utility sector, and includes a translation tool for automatically
importing data from utility company databases of underground assets.
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Dieter SchmalstiegEmail: |
232.
Multiband reduced‐size patch antenna by employing a modified DMS‐spur‐line combo technique
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Jose A. Tirado‐Mendez Hildeberto Jardon‐Aguilar Ruben Flores‐Leal Arturo Rangel‐Merino 《国际射频与微波计算机辅助工程杂志》2018,28(4)
In this article, a simple but effective combination of DMS and spur‐lines is achieved to obtain a multiband patch antenna. The advantage of this technique is the simplicity to elaborate and the good performance compared to other methods where nulls are present in the radiation pattern at the main lobe. The antenna presents five resonant frequencies, which are fully controllable by modifying the dimensions of the defected microstrip structures and spur‐lines, obtaining the characteristic directive radiation pattern and maximum gain above 6 dBi in all bands. 相似文献
233.
234.
M Kalaycio Z Mendez B Pohlman B Overmoyer N Boparai E Jones B Bolwell 《Canadian Metallurgical Quarterly》1998,124(5):265-269
OBJECTIVES: The main aim was to calculate the prevalence of mental pathology in women between 18 and 70 in a Health District of Pamplona; second, to describe comorbidity and to analyse how mental pathology was recorded in the clinical histories. DESIGN: An observational crossover study with randomised selection. SETTING: A community study in the Txantrea quarter of Pamplona, covering 21,590 inhabitants, with 7605 women between 18 and 70. PATIENTS: Randomised sample, stratified by age, of 237 women between 18 and 70 taken from the 1991 Census. MEASUREMENTS AND RESULTS: In a face-to-face interview at the Health Centre, the DIS Questionnaire, which diagnoses mental illness, was administered to all participants. A check was made to see if mental pathology was recorded in their clinical history. The prevalence of mental illnesses, mainly Phobias and Depression, in the "last year of life" was 33.3% (27.5-39.5), which fell to 24.9% (19.7-30.7) when tobacco abuse was excluded. The most common pathologies were: Depression (17.3%), Tobacco dependency (17.3%), simple Phobia (14.8%), Agoraphobia (13.5%), social Phobia (8.9%) and post-traumatic stress (8.0%). CONCLUSIONS: Understanding the high psychological morbidity in these urban women can contribute to the development of Mental Health Promotion and Prevention Programmes and foment fuller mental health training for Primary Care professionals. 相似文献
235.
Guillermo Andrade‐Espinosa Emilio Muñoz‐Sandoval Mauricio Terrones Morinobu Endo Humberto Terrones J Rene Rangel‐Mendez 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2009,84(4):519-524
BACKGROUND: Nitrogen‐doped multi‐walled carbon nanotubes (CNx) and cup‐stacked‐type carbon nanofibres (CST) were modified with nitric acid, at 85 °C, for 1–3 h to enhance their cation adsorption capacity, and were used for cadmium removal from aqueous solutions. These carbon nanostructures were characterized by SEM, EDX, FTIR, BET surface area, TGA and acid/base titrations. In addition, cadmium adsorption experiments were carried out at different pH values and constant temperature. RESULTS: EDX and FTIR revealed a 0.4 times increase in oxygen content after acid treatment, which was reflected in an increment of up to 1.93 mmol g?1 of acid sites and in a shift of about two units of the zero point charge to lower pH values. The BET surface area, in general, decreased as the oxidation time increased. Finally, batch sorption experiments indicated that CNx are more effective than CST to sequester Cd2+ at pH 7; the sorption capacities of these materials increased as pH rose. CONCLUSIONS: The results obtained indicate that it is feasible to modify both physical and chemical properties of the carbon nanostructures CNx and CST by HNO3 in such a way that they can be used to adsorb cations present in aqueous solutions. Copyright © 2008 Society of Chemical Industry 相似文献
236.
R Leyva‐Ramos JR Rangel‐Mendez LA Bernal‐Jacome MS Berber Mendoza 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2005,80(8):924-933
The adsorption isotherms of cadmium(II) and zinc(II) onto activated carbons were obtained in a batch adsorber. The concentration decay data were obtained in a rotating basket adsorber and were interpreted by a mathematical model, which takes into account the adsorption rate, external mass transport and intraparticle diffusion. The results showed that the overall rate of adsorption of Cd(II) and Zn(II) was mainly controlled by the intraparticle diffusion which was solely due to pore volume diffusion. The contribution of the external mass transport resistance was negligible. The effective pore volume diffusivities of Cd(II) and Zn(II) were predicted reasonably well using the ionic diffusivity of the metal and the void fraction and tortuosity of activated carbon. Copyright © 2005 Society of Chemical Industry 相似文献
237.
Jos M. Sustaita‐Rodríguez Francisco J. Medellín‐Rodríguez Diana C. Olvera‐Mendez Alejandro J. Gimenez Gabriel Luna‐Barcenas 《Polymer Engineering and Science》2019,59(10):2016-2023
The thermal stability and degradation mechanisms of three semicrystalline polymers (polyethylene terephthalate [PET], high‐density polyethylene [HDPE], and polyamide 6 [nylon 6]) were studied. Thermogravimetric traces were acquired first at heating rates of 1°C/min and 10°C/min, and it was determined that the heating rate significantly affected the thermal decay curves of the three polymers. The results allowed the selection of specific temperatures at which to carry out heating and cooling cycles from room temperature to the molten state. The thermal behaviors of HDPE, nylon 6, and PET each had particular characteristics. HDPE showed the highest thermal resistance, whereas nylon 6 displayed the lowest. PET had the lowest activation energy for degradation, 93.5 kJ/mol, and retained 14 wt% after thermal recycling with no influence of molecular weight. Thermal cycling also revealed gradual morphological changes in HDPE, nylon 6, and PET, and their crystals changed from regular to branched spherulites with variations in the nucleation patterns. Fourier‐transform infrared spectroscopy measurements allowed us to explain the early stages of degradation for each polymer. POLYM. ENG. SCI., 59:2016–2023, 2019. © 2019 Society of Plastics Engineers 相似文献
238.
John W. Gibbs Michael J. Kaufman Robert E. Hackenberg Patricio F. Mendez 《Metallurgical and Materials Transactions A》2010,41(9):2216-2223
This work presents a new method of cooling curve analysis to make in situ measurements of the amount of precipitate formed in solid-state phase transformations. The presented technique is based on
a first-principles analysis of thermodynamics and heat flow to develop equations that relate cooling curve data to the amount
transformed. The precipitation of Ag2Al in a binary Al-Ag alloy was examined both as a practical example of this technique and to obtain metallographic measurements
of the amount of precipitation for comparison purposes. 相似文献
239.
This paper presents a coupled phenomenological model of heat transfer and plastic flow around the pin in friction stir welding (FSW). The approach is analogous to the boundary layer analysis in fluid mechanics, and is based on the methodology of scaling. The results are a set of novel closed-form expressions for the maximum temperature reached in the process, the thickness of the shear layer, the shear stress around the pin, the torque and the thermal effect of the shoulder. The model presented focuses on the most common conditions encountered in the practice of FSW, which involve relatively slow translation velocities, relatively high rotation velocities and thin shear layers. The ultimate purpose of this model is to provide simple and accurate expressions useful for providing a temperature and strain rate context for metallurgical analysis of FSW and for the selection of process parameters when using FSW to join novel alloys. 相似文献
240.