In this study, we investigated the rotational characteristics which were comprised of directionality and linearity of target registration error (TRE) as a study in advance to enhance the accuracy of ...contour-based registration in neuronavigation. For the experiment, two rigid head phantoms that have different faces with specially designed target frame fixed inside of the phantoms were used. Three-dimensional coordinates of facial surface point cloud and target point of the phantoms were acquired using computed tomography (CT) and 3D scanner. Iterative closest point (ICP) method was used for registration of two different point cloud and the directionality and linearity of TRE in overall head were calculated by using 3D position of targets after registration. As a result, it was represented that TRE had consistent direction in overall head region and was increased in linear fashion as distance from facial surface, but did not show high linearity. These results indicated that it is possible for decrease TRE by controlling orientation of facial surface point cloud acquired from scanner, and the prediction of TRE from surface registration error can decrease the registration accuracy in lesion. In the further studies, we have to develop the contour-based registration method for improvement of accuracy by considering rotational characteristics of TRE.
The objectives of this thesis research are: (1) to develop a new 3-D computational gait model, (2) to develop a contact model for the knee joint considering the effect of sliding and rolling, ...ligaments and tendons, (3) to develop a methodology for gait experimental validation, (4) to develop a technique for evaluating ligaments strain around the femoraltibia knee joint. The accuracy of the computational model is highly dependent on the accuracy of the input data sets. The gait trial and standing data sets were collected from a commercial optical experimental technique that was generally available in the gait laboratory. However, representative geometry for the knee joint and representative ligament locations around the femoraltibia knee joint were used because of experimental limitations. In previously published contact model studies, the contact force between femoral condyle and tibia surface was based on the depth of penetration and the relative velocity normal to the contact surface, while friction forces are calculated based upon the relative velocities tangential to the surface. However, it is shown that this method is not applicable to be used in the gait analysis. The Average Coordinate Reference System (ACRS) method was developed. Using this methodology the error could be reduced about 40% compared to general Euler angle method used in gait analysis for the same subject. Using the combination of ACRS and discretized joint geometry, the results was improved about 400% compared to the general Euler angle method. Ligament strains were determined using the computational model developed in this thesis. Results of this research compare favorably with the published literature. The lateral and medial condyle contact forces were determined from the total internal forces of the knee joint and the twelve ligament reaction forces. In order to solve this problem, a least square method was used. In order to verify the generality of the model and to check the possibility of clinical application of the methodology an ACL injured subject was tested. And results are compared to healthy subject data.
•A unprecedented photolithography process for patterning of large-area CVD-grown 2D material films is discussed.•A specific photosensitive resist allows for better metal lift-off process on patterned ...2D films.•MoS2 field-effect transistors are built using this technique as a proof of efficacy.
In modern electronics, two-dimensional (2D) materials which possess atomically thin layers and periodic network structures have emerged as a new paradigm of materials with a lot of potentials. To fully realize the important commercial applications that 2D materials in modern electronics, one of the key issues, such as development of adequate lithographic processing for 2D materials, must be resolved. Here, we report an unprecedented and reliable photolithographic process for large-area patterning of molybdenum disulfide (MoS2) films on both SiO2/Si and polymer substrates, as well as a lift-off of deposited metals on MoS2 films using an Irgacure 651-doped poly(methyl methacrylate) resist and a water-free developer. To verify the feasibility of our process, the fabrication and device performance of MoS2 field-effect transistors (FETs) is also presented. We expect the proposed method to provide a reliable route to device fabrication with 2D materials and to be an important step toward their commercialization.
Batch growth of high-mobility (μFE > 10 cm2V–1s–1) molybdenum disulfide (MoS2) films can be achieved by means of the chemical vapor deposition (CVD) method at high temperatures (>500 °C) on rigid ...substrates. Although high-temperature growth guarantees film quality, time- and cost-consuming transfer processes are required to fabricate flexible devices. In contrast, low-temperature approaches (<250 °C) for direct growth on polymer substrates have thus far achieved film growth with limited spatial homogeneity and electrical performance (μFE is unreported). The growth of a high-mobility MoS2 film directly on a polymer substrate remains challenging. In this study, a novel low-temperature (250 °C) process to successfully overcome this challenge by kinetics-controlled metal–organic CVD (MOCVD) is proposed. Low-temperature MOCVD was achieved by maintaining the flux of an alkali-metal catalyst constant during the process; furthermore, MoS2 was directly synthesized on a polyimide (PI) substrate. The as-grown film exhibits a 4 in. wafer-scale uniformity, field-effect mobility of 10 cm2V–1s–1, and on/off ratio of 105, which are comparable with those of high-temperature-grown MoS2. The directly fabricated flexible MoS2 field-effect transistors demonstrate excellent stability of electrical properties following a 1000 cycle bending test with a 1 mm radius.
The 2015 American Heart Association guidelines recommended pediatric rescue chest compressions of at least one-third the anteroposterior diameter of the chest, which equates to approximately 5 cm. ...This study evaluated the appropriateness of these two types by comparing their safeties in chest compression depth simulated by CT.
Retrospective study with data analysis conducted from January 2005 to June 2015 SETTING:: Regional emergency center in South Korea.
Three hundred forty-nine pediatric patients 1-9 years old who had a chest CT scan.
Simulation of chest compression depths by CT.
Internal and external anteroposterior diameter of the chest and residual internal anteroposterior diameter after simulation were measured from CT scans. The safe cutoff levels were differently applied according to age. One-third external anteroposterior diameters were compared with an upper limit of chest compression depth recommended for adults. Primary outcomes were the rates of overcompression to evaluate safety. Overcompression was defined as a negative value of residual internal anteroposterior diameter-age-specific cutoff level. Using a compression of 5-cm depth simulated by chest CT, 16% of all children (55/349) were affected by overcompression. Those 1-3 years old were affected more than those 4-9 years old (p < 0.001). Upon one-third compression of chest anteroposterior depth, only one subject (0.3%) was affected by overcompression. Rate of one-third external anteroposterior diameter greater than 6 cm in children 8 and 9 years old was 16.1% and 33.3%, respectively.
A chest compression depth of one-third anteroposterior might be more appropriate than the 5-cm depth chest compression for younger Korean children. But, one-third anteroposterior depth chest compression might induce deep compressions greater than an upper limit of compression depth for adults in older Korean children.
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