• Journal of the Korean Mathematical Society
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• v.16 no.1
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• pp.87-93
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• 1979

In this note the geometric realization of a finite group of homotopy classes of self homotopy equivalences by a finite group of diffeomorphisms is investigated. In order for this to be accomplished an algebraic condition, which guarantees a certain group extension exists, must be satisfied. It is shown for a geometrically interesting class of aspherical manifolds, called injective Seifert fiber spaces over a locally symmetric space, that this necessary algebraic condition is also sufficient for geometric realization.

• Communications of the Korean Mathematical Society
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• v.20 no.4
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• pp.703-708
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• 2005

Let ${\varphi}(z)\;=\;({\varphi}_1(Z),{\cdots},{\varphi}_n(Z))$ be a holomorphic self­map of $\mathbb{D}^n$, where $\mathbb{D}^n$ is the unit polydisk of $\mathbb{C}^n$. The sufficient and necessary conditions for a composition operator to be bounded and compact from the Hardy space $H^2(\mathbb{D}^n)$ into $\alpha$-Bloch space $\beta^{\alpha}(\mathbb{D}^n)$ on the polydisk are given.

• Vacuum Magazine
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• v.3 no.2
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• pp.17-20
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• 2016

Piezoelectric nanogenerators are energy harvesting device to convert a mechanical energy into an electric energy using nanostructured piezoelectric materials. This review summarizes works to date on piezoelectric nanogenerators, starting with a basic theory of piezoelectricity and working mechanism, and moving through the reports of numerous nanogenerators using nanorod arrays, flexible substrates and alternative materials. A sufficient power generated from nanogenerators suggests feasible applications for either power supplies or strain sensors of highly integratedl nano devices. Further development of nanogenerators holds promise for the development of self-powered implantable and wearable electronics.

• East Asian mathematical journal
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• v.18 no.1
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• pp.127-136
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• 2002

In this paper we obtain some fixed points theorems of expansive mappings and several necessary and sufficient conditions for the existence of common fixed points of families of self-mappings in metric spaces. Our results generalize and improve the main results of Fisher [1]-[5], Furi-Vignoli [6], $Is\'{e}ki$ [7], Jungck [8], [9], Kashara-Rhoades [10], Liu [13], [14] and Sharma and Strivastava [16].

• Journal of Oral Medicine and Pain
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• v.47 no.2
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• pp.102-106
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• 2022

Necrotizing sialometaplasia is a rare, benign, self-limiting inflammatory process, with most cases occurring in the palatal region. Although the pathophysiology of this condition remains unknown, it has generally been considered an ischemic reaction involving the minor salivary glands. Due to its clinical and histologic similarities to malignant salivary gland tumor, diagnostic biopsy is required. Careful monitoring is also recommended, and clinicians should provide sufficient information for pathologists to ensure the histologic diagnosis.

• School Mathematics
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• v.15 no.3
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• pp.585-601
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• 2013

The purpose of this study is to investigate the relationship of communication skills and self-directed learning ability between mathematically gifted elementary students and non-gifted students. The subjects include 126 mathematically gifted elementary students from gifted education centers and gifted classes in elementary schools in D Metropolitan City and 124 non-gifted students that were non categorized as gifted students or special children in the same city. Employed in the study were the tests of communication skills and self-directed learning ability. Through this study, there are notable differences in communication skills and self-directed learning ability between mathematically gifted students and non-gifted students. Thus, those communication skills and self-directed learning ability should be taken into account when organizing and running a curriculum. In addition, developing a program for mathematically gifted students, as well as in teaching and learning communication skills and self-directed learning ability sufficient to consider the interrelationships between.

• Korean Journal of Social Welfare
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• v.61 no.2
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• pp.5-32
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• 2009

This study investigates the effect of self-esteem and Korean ability on acculturative stress of marriage-based immigrant Asian women in Korea. It also attempts to find out whether self-esteem has any mediating effect between Korean ability and acculturative stress. By using purposive sampling method, 280 samples were collected among Vietnamese, Filipino, and Chinese women in Daegu from Oct. 12th to Nov. 3rd, 2008. The results are as follows: The higher the score of self-esteem and that of Korean ability is, the lower the score of acculturative stress is respectively. It is proved that self-esteem has mediating effect between Korean ability and acculturative stress. Therefore it is emphasized that programs which can improve self-esteem should be provided to marriage-based immigrant women, especially to those who do not have sufficient Korean ability. Sending money to home country shows both direct and indirect effects and subjective economic evaluation shows direct effects on acculturative stress score. For the purpose of the study acculturative stress scale has been modified based on Sandhu and Asrabadi(1994), which turns out to be useful to measure acculturative stress of marriage-based immigrant Asian women in Korea because it reflects their life circumstances quite well. Some practical implications of social work are suggested through discussion.

• Journal of the Korean Society of School Health
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• v.28 no.3
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• pp.200-210
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• 2015

Purpose: This study aimed to examine the use of smart phones and their relationship with self-efficacy and academic achievement among students in 5th to 6th grade. Methods: 954 students in $5^{th}$ to $6^{th}$ grade were selected from three elementary schools in K City through purposive sampling. Data of 591 respondents were analyzed by $x^2$ test, ANOVA, correlation analysis and multiple regression analysis using the SPSS/WIN program. Results: First, 64% of the students possessed a smart phone and female students used their phone more than male students. 47.5% of the students said they first used a smartphone in their $5^{th}$ grade and 11.7% said in their 6th grade. Second, heavier use of smart phones was related to a lower level of self-efficacy (p<.001). Third, the more the students used a smart phone, the less they achieved in academic performance (Korean language: p<.001, mathematics: p<.01). Finally, the biggest factor influencing smart phone addiction was longer use of smart phones. In addition, lower self-efficacy and lower ability to adapt to difficult tasks were the factors influencing the increase in smart phone addiction. Less use of smart phones and higher self-efficacy resulted in higher achievement in academic performance. Conclusion: It is essential to decrease students' use of smart phones and improve their self-efficacy and academic performance. Intervention programs to reduce the use of smart phones should include a profound interest, a personality-oriented educational environment and sufficient dialogues with students at home, schools and the local society, beyond simple regulations to prevent adverse effects.

• Journal of Industrial Technology
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• v.36
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• pp.33-37
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• 2016

Cellulose binding domains (CBDs) of cellulases are thought to assist in the hydrolysis of insoluble crystalline cellulose. To gain sufficient amount of CBDs, the self-cleavable intein tag was used for expression and purification of Trichoderma reesei cellobiohydrolase I CBD in E. coli. Synthetic CBD genes, CBD or linker-CBD were cloned into expression vector pTYB11. Recombinant CBDs were successfully purified by intein mediated purification with an affinity chitin-binding domain. The final yields of recombinant CBD and linker-CBD were 3.2 mg/L and 1.4 mg/L, respectively. The functional bindings of recombinant CBDs were confirmed by Avicel binding experiments. The simple and easy purification method using self-cleavable intein tag can be further used in pretreatment of crystalline cellulose or characterization of engineered CBDs.

• Bulletin of the Korea Photovoltaic Society
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• v.4 no.1
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• pp.28-34
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• 2018

Botswana is a middle-income developing country in Southern Africa with an economy mainly reliant on mineral resources, particularly diamonds. Other sectors of the economy like energy are trailing behind in this country's development. For a long time, Botswana has been relying on imported energy from her neighboring countries. Due to this great dependence, the country has had little control over sufficiency of energy supply, especially during times of shortages in the neighboring countries. As a result, Botswana came up with a number of initiatives over the years to ensure security of supply and self-sufficiency in the energy sector. However, even with the efforts made, currently Botswana is still not self-sufficient and is facing challenges of energy shortages mainly in the power sector. This paper therefore, seeks to review the various policy instruments that have been adopted in Botswana from 1996 to date, identify challenges that come with them and make recommendations on the identified challenges.