• 한국재료학회:학술대회논문집
• /
• 한국재료학회 1992년도 추계학술발표강연 및 논문개요집
• /
• pp.1-1
• /
• 1992

Shape Memory Alloys have attracted the interest of a great number of researchers in the world, and Mexico is not the exception. Research in this field started ten years ago, and is actually an active line covering the classical Cu-based and Ti-Ni alloys, but also the new Fe-based alloys. Although more basic studies have been performed at the present time, interest for applied research and technological goals is increasing. In this work we present a series of studies carried on these Shape Memory Alloys by the groups in Mexico, and explain what the interest of our groups are in the next future in this are of the Materials Science. Interdisciplinary work has been necessary in the characterization of the different alloys, and multiple techniques have been used, like Mossbauer spectroscopy, thermoelectric power, electron microscopy, ultrasound techniques, neutron and x-ray diffraction, calorimetry, among others. Collaboration With other groups in Europe and in the United States have become highly useful and productive, and some examples of such activities are also reported.

• Kyungpook Mathematical Journal
• /
• 제47권3호
• /
• pp.381-392
• /
• 2007

In 1906, da Rios, a student of Leivi-Civita, wrote a master's thesis modeling the motion of a vortex in a viscous fluid by the motion of a curve propagating in $R^3$, in the direction of its binormal with a speed equal to its curvature. Much later, in 1971 Hasimoto showed the equivalence of this system with the non-linear Schr$\ddot{o}$dinger equation (NLS) $$q_t=i(q_{ss}+\frac{1}{2}{\mid}q{\mid}^2q$$. In this paper, we use the same idea as Terng used in her lecture notes but different technique to extend the above relation to the case of $R^3$, and obtained an analogous equation that $$q_t=i[q_{ss}+(\frac{1}{2}{\mid}q{\mid}^2+1)q]$$.

• Restorative Dentistry and Endodontics
• /
• 제45권1호
• /
• pp.9.1-9.7
• /
• 2020

The restorative procedure in posterior teeth involves clinical steps related to professional skill, especially when using the incremental technique, which may fail in the long term. A recent alternative is bulk-fill resins, which can reduce polymerization shrinkage, decreasing clinical problems such as marginal leakage, secondary caries, and fracture. This scientific study aims to report a clinical case using bulk-fill resin with an occlusal matrix. As determined in the treatment plan, an acrylic resin matrix was produced to establish an improved oral and aesthetic rehabilitation of the right mandibular first molar, which presented a carious lesion with dentin involvement. The occlusal matrix is a simple technique that maintains the original dental anatomy, showing satisfactory results regarding function and aesthetic rehabilitation.

• 한국환경보건학회지
• /
• 제19권3호
• /
• pp.64-73
• /
• 1993

The study was conducted to investigate the mechanism of tumor promotion as the time courses and the doses of promoter, and the effect of plant fiavonoids on the TPA-induced ODC responses. The results are summarized as follows: 1. A single, toppical application of 17 nmole of the potent tumor promoter, 12-O-tetradecanoyl phorbol-13-acetate, resulted in an induction of mouse epidermal Ornithine Decarboxylase with a peak at 5 hours after treatment and maximized 5.1 times as large as ODC activities of control. 2. Dose-response curve indicated that the tumor promotion increases proportionally between 1.7 and 170 nmole of TPA. This dose dependency relationship indicated that the ability of TPA to stimulate ODC is linked its ability to promote tumors. 3. Naturally occurring plant fiavonoids with anticarcinogenic and antipromotional activities were tested for their abilities to inhibit ODC response induced by skin tumor promoter TPA. Intra peritoneal administration of fiavonoids compounds (rutin, naphthofiavone, baicalein, quercitrin) and herbal drugs (sophorae rios, crataegi fructus, armeniacae semen) inhibited 17 nmole TPA-induced ODC activities in mouse epidermis in vivo.

• 대한수학회보
• /
• 제56권1호
• /
• pp.83-102
• /
• 2019

For $M{\in}R-Mod$, $N{\subseteq}M$ and $L{\in}{\sigma}[M]$ we consider the product $N_ML={\sum}_{f{\in}Hom_R(M,L)}\;f(N)$. A module $N{\in}{\sigma}[M]$ is called an M-multiplication module if for every submodule L of N, there exists a submodule I of M such that $L=I_MN$. We extend some important results given for multiplication modules to M-multiplication modules. As applications we obtain some new results when M is a semiprime Goldie module. In particular we prove that M is a semiprime Goldie module with an essential socle and $N{\in}{\sigma}[M]$ is an M-multiplication module, then N is cyclic, distributive and semisimple module. To prove these results we have had to develop new methods.

• 대한수학회지
• /
• 제56권5호
• /
• pp.1285-1307
• /
• 2019

For a multiplication R-module M we consider the Zariski topology in the set Spec (M) of prime submodules of M. We investigate the relationship between the algebraic properties of the submodules of M and the topological properties of some subspaces of Spec (M). We also consider some topological aspects of certain frames. We prove that if R is a commutative ring and M is a multiplication R-module, then the lattice Semp (M/N) of semiprime submodules of M/N is a spatial frame for every submodule N of M. When M is a quasi projective module, we obtain that the interval ${\uparrow}(N)^{Semp}(M)=\{P{\in}Semp(M){\mid}N{\subseteq}P\}$ and the lattice Semp (M/N) are isomorphic as frames. Finally, we obtain results about quantales and the classical Krull dimension of M.

• International Journal of Internet, Broadcasting and Communication
• /
• 제15권1호
• /
• pp.243-253
• /
• 2023

Social television encompasses the social media aspect of television viewing. This study attempts to investigate how social television influences Hispanic and national ethnic identification as well as social presence. Based on the theoretical framework of Tajfel and Turner's Social Identity Theory (SIT), this study focuses on the potential influence of social television on Hispanics' ethnic identifications and social presence. With a sample of 100 Hispanic students, we conducted a lab experiment to measure the effects of exposure to ethnic and non-ethnic related Twitter feeds on Hispanic and national ethnic identification along with social presence. Findings reveal that there was no significant difference between those exposed to the ethnic-identity related Twitter feed compared to those exposed to the non-ethnic identity related Twitter feed, followed by the control group not exposed to the Twitter feed at all. Implications were discussed.

• Journal of Cerebrovascular and Endovascular Neurosurgery
• /
• 제25권3호
• /
• pp.347-351
• /
• 2023

Intracranial aneurysms arise in 1-2% of the population and usually present as hemorrhagic strokes. Spontaneous thrombosis of a ruptured intracranial aneurysm occurs in 1-3% and most commonly in giant aneurysms, with complete thrombosis in just 13-20% of the cases. Thrombosis of smaller aneurysms is rare. Here we present a case of a patient who presented with a ruptured intracranial aneurysm that subsequently thrombosed, discovering a neighboring de-novo aneurysm during follow-up. We hypothesized that after thrombosis, the hemodynamic characteristics that contributed to the formation of the first aneurysm were replicated.

• Bulletin of the Korean Chemical Society
• /
• 제23권2호
• /
• pp.229-240
• /
• 2002

Quantum mechanical calculation is performed for the $O(^1D)$ + HCl ${\rightarrow}$OH + Cl reaction using Reactive Infinite Order Sudden Approximation. Shifting approximation is also employed for the l ${\neq}$ 0 partial wave contributions. Various dynamical quantities are calculated and compared with available experimental results and quasiclassical trajectory results. Vibrational distributions agree well with experimental results i.e. product states mostly populated at $v_f$ = 3, 4. Our results also show small peak at $v_f$ = 0, which indicates bimodal vibrational distribution. The results show two significant broad peaks in ${\gamma}_i$ dependence of the cross section, one is at ${\gamma}_i$ = $15^{\circ}-35^{\circ}$ and the another is at ${\gamma}_i$= $55^{\circ}-75^{\circ}$ which can be explained as steric effects. At smaller gi, the distribution is peaked only at higher state ($v_f$ = 3, 4) while at the larger gi, both lower state ($v_f$ = 0) and higher state ($v_f$ = 3, 4) are significantly populated. Such two competing contributions (smaller and larger ${\gamma}_i$) result in the bimodal distribution. From these points we suggest two mechanisms underlying in current reaction system: one is that reaction occurs in a direct way, while the another is that reaction occurs in a indirect way.

• Neonatal Medicine
• /
• 제25권1호
• /
• pp.1-6
• /
• 2018

Extremely low birth weight infants remain at increased risk of intraventricular hemorrhage from the fragile vascular bed of the germinal matrix; the roles of hypotension (ischemia) and reperfusion (hyperemia) in the development of intraventricular hemorrhage are still debated. Cerebrovascular pressure autoregulation protects the brain by maintaining constant cerebral blood flow despite changes in blood pressure. The ontogeny of cerebrovascular pressure autoregulation has not been well established and uncertainty remains about the optimal arterial blood pressure required to support brain perfusion. Another important aspect of premature cerebral hemodynamics is the critical closing pressure--the arterial blood pressure at which cerebral blood flow ceases. Interestingly, in premature infants, the critical closing pressure approximates the mean arterial blood pressure. Often in this unique population, cerebral blood flow occurs only during systole when the diastolic arterial blood pressure is equal to the critical closing pressure. Moreover, the diastolic closing margin, a metric of cerebral perfusion that normalizes diastolic arterial blood pressure to the critical closing pressure, may be a better measure than arterial blood pressure for defining cerebral perfusion in premature infants. Elevated diastolic closing margin has been associated with intraventricular hemorrhage. This review summarizes the current state of understanding of cerebral hemodynamics in premature infants.