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排序方式: 共有177条查询结果,搜索用时 15 毫秒
1.
Antti Voss Niko Hänninen Mohammad Pour-Ghaz Marko Vauhkonen Aku Seppänen 《Materials and Structures》2018,51(3):68
The development of visualizing tools to monitor unsaturated moisture flow in cement-based materials is of great importance, as most degradation processes in cement-based materials are connected to and take place in the presence moisture. This paper investigates the ability of electrical capacitance tomography (ECT) to image two-dimensional (2D) unsaturated moisture flow in cement-based materials. In ECT, the electrical permittivity distribution within an object is reconstructed based on measured capacitances between electrodes attached on the object’s surface. In a series of experiments, mortar specimens with and without discrete cracks were imaged with ECT during a 2D moisture ingress. The results show that ECT is able to monitor the evolution of the moisture flow, and to approximate the shape and position of the moisture front. These findings indicate that ECT is a viable method for monitoring and visualizing 2D unsaturated moisture flow in cement-based materials in the presence and absence of discrete cracks. 相似文献
2.
A prospective clinical trial comparing adverse postmyelographic effects and myelographic quality of metrizamide and iohexol was conducted. Using a predetermined, randomized assignment, 24 horses exhibiting neurologic signs were administered either metrizamide (180 mgl/ml) or iohexol (180 mgl/ml) via cerebellomedullary puncture. Each horse was evaluated postmyelographically for adverse effects. Myelographic quality was assessed by a numerical scoring method. Adverse effects were observed more frequently with metrizamide (21) compared with iohexol (6) myelography (p < 0.05). Seizures, intensification of preexisting neurologic signs and prolonged anesthetic recovery were the most common complications after myelography. There was no difference in myelographic quality (p > 0.05). We conclude that iohexol is safer than metrizamide for equine myelography and that quality myelograms can be obtained with either contrast medium. 相似文献
3.
Ye Liang Yan Susu Zhen Jialing Han Tian Ferdinando Hany Seppänen Tapio Alasaarela Esko 《Mobile Networks and Applications》2022,27(4):1688-1699
Mobile Networks and Applications - In recent years, physical violence detection has become a research hotspot in the area of human activity recognition. With the improvement and full coverage of... 相似文献
4.
We have previously described in tuberous sclerosis (TSC) hamartomas the phenomenon of loss of heterozygosity (LOH) for DNA markers in the region of both the TSC2 gene on chromosome 16p13.3 and the TSC1 gene on 9q34. We now describe the spectrum of LOH in 51 TSC hamartomas from 34 cases of TSC. DNA was extracted from leucocytes or normal paraffin embedded tissue, and from frozen paraffin embedded hamartoma tissue from the same patient. The samples were analysed for 11 markers spanning the TSC1 locus and nine markers spanning the TSC2 locus. Twenty-one of 51 hamartomas showed LOH (41%). There was significantly more LOH on 16p13.3, with 16 hamartomas showing LOH around TSC2, and five in the vicinity of TSC1. No hamartoma showed LOH for markers around both loci. All the areas of LOH on chromosome 9 were large, but the smallest region of overlap lay between the markers D9S149 and D9S114, providing independent evidence for the localisation of the TSC1 gene. These data show that LOH is a common finding in a wide range of hamartomas, affecting the same TSC locus in different lesions from the same patient but not affecting both loci. These data support the hypothesis that both the TSC genes act as tumour suppressors and that the manifestations of TSC in patients with germline TSC mutations rise from "second hit" somatic mutations inactivating the remaining normal copy of the TSC gene. 相似文献
5.
Ari Seppälä Mamdouh El Haj Assad Tero Kapanen 《Structural and Multidisciplinary Optimization》2008,36(4):355-363
A suitable combination of materials for sheltering a system from a sudden change of environmental temperature has been theoretically
studied. The protective composite wall consists of two materials. An insulating material is placed on the outer surface, while,
for the inner surface, materials that have good heat storage properties but negligible heat transfer resistance are chosen.
The results show that by replacing some of the insulation material with a heat storage material, the temperature of the protected
system can be maintained at a considerably lower level. Although the optimal thickness ratio X depends on the Biot number, Fourier number, and on the heat capacity ratio K
C, for a large number of thermal protection cases, the approximation X = 0.45 yields practically the minimum progress of the transient. If the Biot number is sufficiently small, it is better to
replace all of the insulation material with a good heat storage material. 相似文献
6.
NMR measurements are reported on rotating3He-A in a long cylindrical geometry of 5 mm diameter at a liquid pressure of 29.3 bar and in axial magnetic fields of 14.2, 28.4, and 56.9 mT. At 28.4 mT, NMR studies are also reported in fields inclined by 25° and 90° from the axis of rotation. The frequency shift, the width, and the intensity of the spin wave modes localized on the soft vortex cores, as well as the additional broadening of the main NMR line during rotation, were measured as a function of temperature, angular velocity , magnetic field intensity, and its inclination angle. Also observed were a critical angular velocity of vortex formation, hysteretic behavior in the number of vortices when comparing accelerating rotation to decelerating, and metastable vortex densities, presumably a vortex tangle after rapid oscillatory acceleration. The results can be understood in terms of the continuous 4 vortices first proposed by Seppälä and Volovik. 相似文献
7.
A method for embedding a watermark in print media, posters or other paper printouts and reading the watermark information blindly with a camera phone is proposed. A subtractive-additive embedding method is applied in which the message is coded with a directed periodic pattern. The message is detected and read by searching regularities in the autocorrelation function of a periodic signal. The robustness to disturbance occurring during printing process due to air interface and camera phone properties is ensured using noise reduction, modified JND model, enhanced peak detection with filtering and shaping and two-level coding of the message. The validity of the approach is proven with tests, and an application example of an interactive poster is examined. 相似文献
8.
Enzymatically treated cellulose was dissolved in a NaOH/ZnO solvent system and mixed together with poly(ethylene‐co‐acrylic acid) (PE‐co‐AA) or poly(acrylamide‐co‐acrylic acid) (PAA‐co‐AA) polymers, in order to improve the properties of dissolved cellulose and to prepare homogeneous cellulose‐based blends for films and coatings. The solution stage properties of the blends were evaluated by rheological methods and the precipitated dry blends were characterized by dynamic mechanical analysis, differential scanning calorimetry, and scanning electron microscopy. Paperboard coating tests done at laboratory scale showed dissolved cellulose/acrylic acid copolymer‐based blends function well as coating materials. All of the tested blends showed a good resistance against grease in the coating trials, having grease resistance from 60 to 69 days despite a very thin (~2 µm) coating layer. In addition, cellulose/PE‐co‐AA coating showed improved water vapor and oxygen barrier properties when compared with neat dissolved cellulose‐coated paperboard. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40286. 相似文献
9.
Anu Kärkkäinen Panu Pekko James Dekker Nadine Pesonen Mika Suhonen Aarne Oja Jukka Kyynäräinen Heikki Seppä 《Microsystem Technologies》2005,12(1-2):169-172
We have designed and manufactured a micromachined moving plate capacitor to be used as an AC voltage reference in electrical metrology. The reference is based on the characteristic AC current–voltage curve of the component having a maximum, the value of which ideally depends only on the geometry of the component and material properties of single crystalline silicon. The electrode surface stability is essential in this application and hence a new fabrication process has been developed to metallize both surfaces of an electrostatically actuated micromachined structure. The stability of the AC reference voltage at a frequency of 100 kHz and an RMS voltage value 6.4 V was measured to be ±60 ppm over 14 h. 相似文献
10.
Reetta Sartoneva Anne-Marie Haaparanta Tuija Lahdes-Vasama Bettina Mannerstr?m Minna Kellom?ki Minna Salom?ki George Sándor Riitta Sepp?nen Susanna Miettinen Suvi Haimi 《Journal of the Royal Society Interface》2012,9(77):3444-3454
Different synthetic biomaterials such as polylactide (PLA), polycaprolactone and poly-l-lactide-co-ε-caprolactone (PLCL) have been studied for urothelial tissue engineering, with favourable results. The aim of this research was to further optimize the growth surface for human urothelial cells (hUCs) by comparing different PLCL-based membranes: smooth (s) and textured (t) PLCL and knitted PLA mesh with compression-moulded PLCL (cPLCL). The effects of topographical texturing on urothelial cell response and mechanical properties under hydrolysis were studied. The main finding was that both sPLCL and tPLCL supported hUC growth significantly better than cPLCL. Interestingly, tPLCL gave no significant advantage to hUC attachment or proliferation compared with sPLCL. However, during the 14 day assessment period, the majority of cells were viable and maintained phenotype on all the membranes studied. The material characterization exhibited potential mechanical characteristics of sPLCL and tPLCL for urothelial applications. Furthermore, the highest elongation of tPLCL supports the use of this kind of texturing. In conclusion, in light of our cell culture results and mechanical characterization, both sPLCL and tPLCL should be further studied for urothelial tissue engineering. 相似文献