EFFECTS OF DIFFERENT HEIGHTS OF BOX DROP VERTICAL JUMP ON THE CHRONIC ANKLE INSTABILITY INDIVIDUALS

The purpose of this study was to investigate the effects of different height of box drop vertical jump DVJ) among the healthy control, coper, and CAI groups. Participants were asked to perform a box drop vertical jump and followed with a single-leg landing on the force plate. The DVJ height was 10cm, 30cm, and 50cm. Results from the current study indicated two major findings: Three groups showed difference in frontal plan and sagittal plane when doing 50cm DVJ task, In sequence for CAI ,coper and healthy group. Our findings indicated that different landing strategy of ankle joints exist among 3 groups

Microstructure Evolution of Metals through Thermo-Mechanical Processes (TMP), Mechanical Property of TMP Samples, and Small Scale Test Samples.

The goal of the research is to improve the mechanical properties of hard-to-deform metal alloys, such as Mg and Ti alloys, through thermo-mechanical processes. The emphasis has been put on the grain-refinements of the metal alloys through different processing routes. Many novel thermo-mechanical processing techniques have been developed and tested on metal materials. Alternate biaxial reverse corrugation ( ABRC ) process has been conducted on the ZK60 and Mg-Ga alloy. Angle die pressing and hot rolling has been conducted on Ti-6Al-4V alloy. Biaxial extrusion process has been conducted on Ti-6Al-4V, ZK60 alloys and various Mg-base alloys. The overall mechanical properties of processed metal alloys showed apparent improvement both in strength and ductility. Also, tensile tests have been done on small scale tensile samples (~400μm2 in cross-sectional area) to examine the effect of size on the mechanical property of metal. The test results indicated that samples with small size have higher strength relative to the conventional large samples.Ph.D.Materials Science and EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/75984/1/ricklee_1.pd

Structural study in Highly Compressed BiFeO3 Epitaxial Thin Films on YAlO3

We report a study on the thermodynamic stability and structure analysis of the epitaxial BiFeO3 (BFO) thin films grown on YAlO3 (YAO) substrate. First we observe a phase transition of MC-MA-T occurs in thin sample (<60 nm) with an utter tetragonal-like phase (denoted as MII here) with a large c/a ratio (~1.23). Specifically, MII phase transition process refers to the structural evolution from a monoclinic MC structure at room temperature to a monoclinic MA at higher temperature (150oC) and eventually to a presence of nearly tetragonal structure above 275oC. This phase transition is further confirmed by the piezoforce microscopy measurement, which shows the rotation of polarization axis during the phase transition. A systematic study on structural evolution with thickness to elucidate the impact of strain state is performed. We note that the YAO substrate can serve as a felicitous base for growing T-like BFO because this phase stably exists in very thick film. Thick BFO films grown on YAO substrate exhibit a typical "morphotropic-phase-boundary"-like feature with coexisting multiple phases (MII, MI, and R) and a periodic stripe-like topography. A discrepancy of arrayed stripe morphology in different direction on YAO substrate due to the anisotropic strain suggests a possibility to tune the MPB-like region. Our study provides more insights to understand the strain mediated phase co-existence in multiferroic BFO system.Comment: 18 pages, 6 figures, submitted to Journal of Applied Physic

Existence theorems for a crystal surface model involving the p-Laplace operator

The manufacturing of crystal films lies at the heart of modern nanotechnology. How to accurately predict the motion of a crystal surface is of fundamental importance. Many continuum models have been developed for this purpose, including a number of PDE models, which are often obtained as the continuum limit of a family of kinetic Monte Carlo models of crystal surface relaxation that includes both the solid-on-solid and discrete Gaussian models. In this paper we offer an analytical perspective into some of these models. To be specific, we study the existence of a weak solution to the boundary value problem for the equation - \Delta e^{-\mbox{div}\left(|\nabla u|^{p-2}\nabla u\right)}+au=f, where $p>1, a>0$ are given numbers and $f$ is a given function. This problem is derived from a crystal surface model proposed by J.L.~Marzuola and J.~Weare (2013 Physical Review, E 88, 032403). The mathematical challenge is due to the fact that the principal term in our equation is an exponential function of a p-Laplacian. Existence of a suitably-defined weak solution is established under the assumptions that $p\in(1,2], \ N\leq 4$, and $f\in W^{1,p}$. Our investigations reveal that the key to our existence assertion is how to control the set where -\mbox{div}\left(|\nabla u|^{p-2}\nabla u\right) is $\pm\infty$

A rare, highly aggressive primitive neuroectodermal tumor of the kidney: Case report and literature review

AbstractWe report a case of a 14-year-old boy who initially suffered from a sudden onset of abdominal pain for 2 weeks with a protrusive soft mass over the left upper abdomen. No obvious symptomatic symptoms or body weight loss were observed. However, early lung metastasis was detected after an initial computed tomographic examination. Even after we performed salvage en bloc resection of the huge retroperitoneal tumor after primary neoadjuvant chemotherapy, the final outcome was still poor. A diagnosis according to radiologic findings was uncharacteristic. Finally, a pathologic diagnosis based on histologic and immunohistochemical results revealed a rare renal peripheral primitive neuroectodermal tumor