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991.
The design and performance of composite prosthetic devices can be improved by tailoring the material properties to achieve a prescribed response. An example of such a response would be displacements and stresses exhibited by healthy, undisturbed femoral bone. In this paper, an inverse design methodology, used in the Volumetrically Controlled Manufacturing (VCM) process, is developed and tested for improving the design of orthopedic prosthetic devices. First, a three-dimensional finite element (FE) model is developed based on available Computed Tomography (CT) data. The FE model is used to evaluate the response of the model subjected to a typical load. Second, as a part of the VCM process, the inverse design process is used to formulate a design problem that is in the form of a constrained least-squares problem. The intent is to find the material properties of the FE model to obtain a known displacement field on the stem-cancellous interface. Third, a solution methodology is developed to solve this constrained least squares problem using the finite element analysis for function evaluations and a gradient-based nonlinear programming (NLP) method to solve the design problem. Two test problems are solved to illustrate the developed methodology. The results indicate that material properties can be tailored to meet specific response requirements.  相似文献   
992.
Abstract

Stem cells are known for their potential to repair damaged tissues. The adhesion, growth and differentiation of stem cells are likely controlled by the surrounding microenvironment which contains both chemical and physical cues. Physical cues in the microenvironment, for example, nanotopography, were shown to play important roles in stem cell fate decisions. Thus, controlling stem cell behavior by nanoscale topography has become an important issue in stem cell biology. Nanotechnology has emerged as a new exciting field and research from this field has greatly advanced. Nanotechnology allows the manipulation of sophisticated surfaces/scaffolds which can mimic the cellular environment for regulating cellular behaviors. Thus, we summarize recent studies on nanotechnology with applications to stem cell biology, including the regulation of stem cell adhesion, growth, differentiation, tracking and imaging. Understanding the interactions of nanomaterials with stem cells may provide the knowledge to apply to cell–scaffold combinations in tissue engineering and regenerative medicine.  相似文献   
993.
Detailed studies on the effect of placing a thin (10 nm) solution‐processable interlayer between a light‐emitting polymer (LEP) layer and a poly(3,4‐ethylenedioxythiophene)/poly(styrenesulfonic)‐acid‐coated indium tin oxide anode is reported; particular attention is directed at the effects on the hole injection into three different LEPs. All three different interlayer polymers have low ionization potentials, which are similar to those of the LEPs, so the observed changes in hole injection are not due to variations in injection barrier height. It is instead shown that changes are due to variations in hole trapping at the injecting interface, which is responsible for varying the hole current by up to two orders of magnitude. Transient measurements show the presence of very fast interfacial traps, which fill the moment charge is injected from the anode. These can be considered as injection pathway dead‐ends, effectively reducing the active contact surface area. This is followed by slower interfacial traps, which fill on timescales longer than the carrier transit time across the device, further reducing the total current. The interlayers may increase or decrease the trap densities depending on the particular LEP involved, indicating the dominant role of interfacial chain morphology in injection. Penetration of the interlayer into the LEP layer can also occur, resulting in additional changes in the bulk LEP transport properties.  相似文献   
994.
Abstract: The development of robotics technology, especially the emergence of automatic surgical tools and robots, as well as the rapid advances in virtual reality techniques, require closer examination of the mechanical properties of the brain and its tissues at moderate and slow loading velocities corresponding to the strain rates of surgical procedures. In order to obtain comprehensive information about the mechanical properties of the brain, non‐destructive instrumented indentation was performed on the adult ovine cerebrum under various conditions, i.e. (i) in four measuring regions (consistent with the frontal and parietal lobes of both cerebral hemispheres) and (ii) at three loading velocities. The shear and elastic moduli show loading velocity dependence and weak regional dependence. The mean shear and elastic moduli of the ovine brain’s frontal lobe are higher than those of its parietal lobe. In addition, the left lobe is insensibly stiffer than the right lobe at each of the loading velocities.  相似文献   
995.
996.
OKCashbag (OCB), the largest coalition loyalty program in Korea, offers a number of benefits such as sharing customer data with participating firms and cross-selling. There is great value in utilizing information pertaining to coalition loyal patrons. However, the size of transaction data is huge. We propose how to create necessary summary information by reducing the dimension of coalition transaction data. This information is then utilized to develop a behavior-scoring model. We expect that our study results can contribute to big data analysis for coalition loyalty program.  相似文献   
997.
998.
Although successful examples of thermoelectric materials with the “rattler-in-a-cage” structure include filled skutterudites and clathrate compounds, there has been no report on “rattling” oxides. Here we report the thermal properties of defect pyrochlore (β-pyrochlore) oxides with smaller cations in an oversized cage-like crystal structure. It is clearly shown that the thermal diffusivity, α, and the thermal conductivity, κ, are lower for the oxides containing lighter A-site cations, contradicting the conventional prediction of the phonon thermal conductivity, in which lighter comprising atoms must give higher α and hence κ. These results strongly suggest that the smaller A-site cations with larger size mismatch to the surrounding cage structure enhance the phonon scattering and thereby reduce α and κ. These findings directly evidence the “rattling” effect of the loosely bound cations on the thermal transport properties of oxide materials.  相似文献   
999.
The main aim of this study is to analyze both domestic and imported marine products in Korea for 14 sulfonamide antimicrobials. Monitoring samples included flatfish, jacopever, sea bream, common eel, blue crab, shrimp, and abalone. In analyzing step, the residues of 14 sulfonamides (SAs) were determined by high-performance liquid chromatography (HPLC) with photodiode array detector. And in confirmatory step, ultra-performance liquid chromatography-tandem mass spectroscopy (UPLC-MS/MS) was used for unequivocal identification of target compounds.No sulfonamide antimicrobials were found in more than 99% of the samples analyzed in this study. The monitoring results revealed that sulfadiazine was detected in two samples (flatfish and jacopever) below the maximum residue limit (MRL), 100 ?/㎏ as the sum of 14 sulfonamides. Of samples, one common eel containing sulfamethoxazole above the legal residue limit was found, and the detected concentration was 5104 ?/㎏.  相似文献   
1000.
Polythienothiophene:poly(perfluoroethylene-perfluoroethersulfonic acid) (PTT:PFFSA) has been used to enhance hole injection into small molecule OLEDs. Compared to devices with polyethylene dioxythiophene polystyrene sulfonate (PEDOT:PSS) as the hole injection layer (HIL), the OLED using PTT:PFFSA as a HIL gives enhanced efficiency and a slower luminance decay as well as a slower rise in operating voltage. Further studies of capacitance–voltage characteristics reveal that positive trapped charges accumulate in the hole transporting layer during operation. These results thus highlight the significance of hole injection layer to OLED operational stability.  相似文献   
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