Effect of the TiO2 Nanoparticles on the Growth Behavior of Intermetallics in Sn/Cu Solder Joints

Shengyan Shang,Anil Kunwar,Jinye Yao,Yanfeng Wang,Haitao Ma,Yunpeng Wang 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.2

In order to investigate the effect of TiO2 nanoparticles on growth behavior of interfacial Cu6Sn5 intermetallics compounds(IMCs) in Pb-free Sn/Cu system, the solder joints are fabricated by using flux doped with different content (0.0–2.0 wt% offlux) and particle diameter (5 nm and 50 nm) of TiO2 . In context of isothermal reflow soldering at 250 °C and subsequentair cooling, the increase in reflow duration from 10 to 120 s was characterized with an increment in IMC layer thicknessand grain size, due to the enhancement of Cu flux contribution for Ostwald ripening during constant temperature reflow andprecipitation kinetics during cooling. The increased proportion of TiO2 nanoparticles in flux was found to reduce the growthof IMC layer and grain size. The suppression effect on IMC was more pronounced for 5 nm particles as compared to the 50nm TiO2 . The TiO2 nanoparticles, adsorbed on IMC plane can retard the growth of the latter. Presence of sufficient amountof a given sized TiO2 nanoparticles among IMCs, by increasing the effective stress at the localized interfaces, and causingthe breaking of brittle Cu6Sn5 during growth stage; can help in the inhibition of IMC whisker formation. Particle diameterand mass proportion of TiO2 nanoparticles are important for soldering materials design.

중국(中國)에서 출판(出版)된 한국어(韓國語) 교재(敎材)의 문제점(問題點) 고찰(考察) -단모음(單母音) 설명(說明) 부분(部分)을 중심(中心)으로-

왕요(王瑤) ( Wang¸ Yao ) 한국어문교육연구회 2021 어문연구(語文硏究) Vol.49 No.3

본 연구는 2010년 이후부터 현재까지 중국에서 출판된 정규 대학 기관용 한국어 교재에 제시된 단모음의 설명 부분을 분석하여, 문제점을 고찰하는 것을 목적으로 하였다. 현재 중국의 한국어 교육 현장에서 사용되고 있는 중국에서 출판된 한국어 교재에서 단모음의 발음 기호를 제시하는 데에 가장 혼란스러운 단모음인 /ㅓ, ㅗ, ㅡ, ㅐ, ㅚ/의 IPA 기호는 각각 [Λ](긴소리일 때 [əː]), [o], [ɨ], [ε], [ø]로 표기해야 한다고 보았다. 단모음을 체계적으로 제시할 때 음운론적 분류표에서는 굳이 중설모음을 설정할 필요가 없고, /ㅡ, ㅓ, ㅏ/는 후설모음으로 분류해야 할 것으로 보았다. 음성학적 분류표에서는 중설모음을 설정할 필요가 있으며, 이때 /ㅓ/는 후설 평순 반개모음에 해당하지만, 긴소리 /ㅓ/는 중설 반폐모음에 해당한다. 단모음을 기술할 때 ‘홑모음'이나 ‘모음(元音)’이라는 용어보다는, ‘단모음(單元音)’이라는 용어를 사용하는 것이 더 타당하다고 하였다. 실험음성학적 분석 결과, 한국어 /ㅣ, ㅏ, ㅜ/는 각각 중국어 /i, a, u/와 동일한 소리로 볼 수 있지만, 한국어 /ㅗ/는 중국어 /o/와 동일한 소리로 볼 수 없다. 이뿐만 아니라 한국어 /ㅓ, ㅡ/의 발음이 모두 중국어 /e/의 발음과 다르다는 현실을 밝혔다. The purpose of this study is to analyze the simple vowels presented in Korean textbooks for regular university institutions published in China, starting from 2010 until now, examine the problems, and make recommendations. The most confusing IPA symbols of /ㅓ,ㅗ,ㅡ, ㅐ, andㅚ /, which are used for simple vowels in Korean textbooks published in China, [Λ] ([əː] should be applied to long sounds), [o], [ɨ], [ε], and [ø]. When presenting simple vowels systematically, it is not necessary to set central vowels in the phonological classification table, and /ㅡ, ㅓ, ㅏ/ were classified as central vowels. In the phonetic classification table, it is imperative to set a central vowel. In this case, / ㅓ/ corresponds to a flat-order half-closed vowel, but a long sound / ㅓ/ corresponds to a half-closed vowel. When describing simple vowels, it can be argued that it is more advantageous to use the term ”simple vowels” rather than “one vowel” or “vowel.” The experimental phonetic analysis showed that Korean / ㅣ, ㅏ, ㅜ/ can be considered to have the same sound as Chinese /i, a, and u/, respectively, but Korean / / cannot be regarded as equivalent to Chinese /o/. Furthermore, it also revealed that the pronunciations of Korean / ㅓ, ㅡ/ differ from those of Chinese /e/.

중국에서 출판된 한국어 교재의 문제점 고찰 - 자음의 발음 교육 부분을 중심으로 -

왕요 ( Wang¸ Yao ) 반교어문학회 2020 泮橋語文硏究 Vol.0 No.56

이 연구는 2010년 이후부터 현재까지 중국에서 출판된 정규 대학 기관용 한국어 교재를 대상으로 자음의 발음 교육 자료를 분석하고 문제점을 고찰하는 것을 목적으로 하였다. 나아가 문제점에 대한 해결 방안을 제시하였다. 자음의 발음 기호를 제시하는 데에서 평음을 무성화된 유성음으로 표기해야 한다고 보았다. 기본 국제 음성 문자에 무기음임을 나타내는 구별 기호 ‘○̿ ’를 붙여야 경음의 올바른 음가, 무기음임을 나타내는 구별 기호 ‘○ʰ’를 붙여야 격음의 올바른 음가라고 보았다. 자음 분류표 같은 경우, 초급 한국어 학습자에게 제시할 때 치마찰음과 경구개 파찰음을 묶어서 설면전음으로 분류하는 것은 바람직하지 않다고 하였다. 또한 /ㄹ/의 조음 방법을 유음으로 기술하는 것이 더 타당하다고 하였다. 발성 유형을 기술할 때 ‘松音(평음), 緊音(경음), 有氣音(격음)’이라는 용어들을 사용하는 것이 학습자들에게 ‘평·경·격음’의 발성 유형에 파악하는 데에서 도움이 될 수 있으리라 보았다. 실험음성학적 분석 결과, 한국어 평음에 비해 경음은 중국어 무기음과 더 유사하다. 중국어권 학습자에게 한국어의 자음을 가르칠 때, 한국어 평음의 발음이 중국어 무기음의 발음과 다르다는 점을 강조해야 한다는 입장을 밝혔다. The purpose of this study is to analyze the education materials of consonants pronunciation and to examine problems in Korean textbooks for regular university institutions, published in China from 2010 to the present. Furthermore, to suggest a solution to these problems. First of all, in presenting the pronunciation symbols of consonants, this study believes that the unvoiced lax consonants should be marked as voiced consonants. Secondly, the phonetic value can be approved only if when the separator‘○̿ ’is attached to the basic international phonetic character for tense consonants, and ‘○ʰ’for aspirated consonants. Thus, when presenting consonants systematically for beginner Korean learners, it is not desirable to classify them as lingual frontal consonants by combining the voiceless dental fricative consonants and voiceless palatal affricate consonants. Moreover, It is more appropriate to describe the articulation method of /ㄹ/ as a fluid consonant. Lastly, when describing the types of vocalization, the use of the terms "lax consonants", "tense consonants", and "aspirated consonants" would be a great help to learners in grasping the different types of "lax·tense·aspirated" consonants. As a conclusion, it is proved that when teaching Korean consonants to Chinese-speakers Korean learners, it should be emphasized that the pronunciation of Korean lax consonants are different from Chinese unaspirated consonants.

중국에서 출판된 한국어 교재의 문제점 고찰 -음운 현상 교육 부분을 중심으로-

왕요 ( Wang¸ Yao ) 국어학회 2021 국어학 Vol.- No.99

본 연구는 최근 10년간 중국에서 출판된 정규 대학 기관용 한국어 교재를 대상으로 한국어 교재에서 제시하고 있는 음운 현상 교육 자료를 살펴보고, 각 교재에 제시된 한국어의 음운 현상에 대한 설명을 검토하는 데 목적이 있다. 이를 토대로 현행 한국어 교재의 문제점을 지적하고 각 음운 현상의 규범적인 한국어 및 중국어 기술 내용을 제시하였다. 현재 중국의 한국어 교육 현장에서 사용되고 있는 중국에서 출판된 한국어 교재를 살펴본 결과, 음운 현상에 대한 비규범적인 설명이 포함된 교재는 총 10종이 있다. 교재에서 평파열음화, 장애음의 비음화, 유음의 비음화, 합성 명사에서의 경음화, ‘ㄹ’ 뒤의 경음화, 자음군 단순화, ㄴ-첨가, 모음 축약, 유기음화, 그리고 연음, 총 10종의 음운 현상에 대한 비규범적인 설명이 발견된다. 특히 /ㄹ/는 ‘장애음의 비음화’와는 무관하므로 중국에서 출판된 한국어 교재에서 제시한 “/ㄱ, ㄷ, ㅂ/ 뒤에 공명음 /ㄴ, ㅁ, ㄹ/가 올 때, 그 소리는 /ㅇ, ㄴ, ㅁ/로 바뀐다.”와 같은 설명은 적절하지 않다. 또한 ‘음료수’가 [음뇨수]로 발음되는 현상은 ‘특수 음변(特殊音變)’이 아니라 유음의 비음화 현상으로 설명되어야 함을 지적하였고, ‘ㄹ’ 뒤의 경음화 현상을 “한자어 ‘ㄹ’ 뒤의 경음화”와 “관형사형 어미 ‘-을’ 뒤의 경음화” 두 가지로 나누어 학습자들에게 교육해야 함을 주장하였다. 그리고 ‘보+아서→봐서, 되+어서→돼서, 하+여→해’ 같은 경우는 음운의 차원으로 봤을 때는 축약 현상이 아니라는 것을 주의 깊게 학습자들에게 설명해야 할 것이다. The purpose of this study is to examine the phonological phenomenon in the educational materials presented in Korean textbooks for regular university institutions published in China over the past 10 years, and to examine the explanations of phonological phenomena in Korean presented in each textbook. Based on this, problems of current Korean textbooks were pointed out, and normative Korean as well as Chinese descriptions of each phonological phenomenon were presented. As a result of examining the Korean textbooks published in China, which are currently used in the field of Korean language education over there, there are a total of 10 textbooks that contain non-normal explanations of phonological phenomena. On the other hand, among the numerous phonological phenomena of Korean, in Korean textbooks published in China, syllable final unreleasing, obstruent nasalization, liquid nasalization, fortition in compound noun, fortition after ‘ㄹ’, consonant cluster simplification, ㄴ-insertion, vowel contraction, totally non-normative explanations for 10 types of phonological phenomena, including aspiration and liaisons, are found. Especially, what is mentioned about /ㄹ/ has nothing to do with ‘nasalization of Obstruent’ in the Korean textbooks published in China, “when the Sonorant /ㄴ, ㅁ, ㄹ/ comes after /ㄱ, ㄷ, ㅂ/ this sound changes to /ㅇ, ㄴ, ㅁ/.” is not considered appropriate explanation. In addition, this study has pointed out that the phenomenon of ‘음료수’ being pronounced [음뇨수] should be explained not as a ‘special sound change’ but as a nazalation phenomenon of the liquid consonants. It was suggested that the learners should be educated by dividing them into two categories: “Fortis phenomenon after the Korean character ‘ㄹ’” and “Fortis phenomenon after the adnominal suffix ‘-을’”. Moreover, it should be carefully explained to the learners that in the case of ‘보+아서→봐서, 되+어서→돼서, 하+여→해’ is not an abbreviation phenomenon in terms of phonology.

A novel design method for improving collapse resistances of multi-story steel frames with unequal spans using steel braces

Zheng Tan,Wei-hui Zhong,Bao Meng,Shi-chao Duan,Hong-chen Wang3,Xing-You Yao,Yu-hui Zheng 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.47 No.2

The bearing capacities resisted by the two-bay beams of multi-story planar frames with unequal spans under column removal scenarios differ considerably owing to the asymmetric stress on the left and right beams connected to the failed column and cause the potential for beams with larger span-to-depth ratios to be unable to exert effectively, which is disadvantageous for resisting the vertical load in unequal-span frame structures. To address this problem, the structural measure of adding braces to the weak bays of multi-story unequal-span frames was proposed, with the objective of achieving a coordinated stress state in two-bay beams with unequal spans, thereby improving the collapse resistance of unequal-span frame structures. Before conducting the numerical simulation, the modeling methods were verified by previous experimental results of two multi-story planar frames with and without steel braces. Thereafter, the effects of the tensile and compressive braces on the collapse behavior of the frame structures were elucidated. Then, based on the mechanical action laws of the braces throughout the collapse process, a detailed design method for improving the collapse resistance of unequal-span frame structures was proposed. Finally, the proposed design method was verified by using sufficient example models, and the results demonstrated that the design method has good application prospects and high practical value.

Dynamic simulation and analysis of the elevating mechanism of a forklift based on a power bond graph

Yao Wang,Dingxuan Zhao,Lei Wang,Zhuxin Zhang,Lili Wang,Yanjuan Hu 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.9

An electric elevating mechanism is designed based on the working principle of the lifting equipment for the CPD30 forklift. The mathematical models based on the power bond graph for an electric elevating system and a hydraulic elevating system are built by considering the execution condition of the fork arms of a forklift, including starting, rising and braking. On the basis of these models, dynamic simulation and analysis are performed for the starting, rising and braking of the fork arms frame. Then, the corresponding mathematical model is derived. Furthermore, the curve of the movement velocity of the fork arms frame is determined. The characteristics of the two types of lifting mechanism are summarized for two types of working effect of the lifting system under the same conditions by comparing the difference between the actual trajectory curve and the curve of the original plan. The theoretical foundations for the type selection of the forklift elevating mechanism and even that of engineering machinery are provided.

On the Locality Modeling of Web Access Stream

Huixia Wang,Yao Yao 보안공학연구지원센터 2014 International Journal of Grid and Distributed Comp Vol.7 No.5

Using mathematical method to model Web workload locality characteristics is established based on the study of entropy and coefficient of variation. Experiments show that these metrics can depict locality characteristics more properly and are much easier to use.

Efficiently targeted therapy of glioblastoma xenograft via multifunctional biomimetic nanodrugs

Zhipeng Yao,Xiaochun Jiang,Hong Yao,Yafeng Wu,Fan Zhang,Cheng Wang,Chenxue Qi,Chenhui Zhao,Zeyu Wu,Min Qi,Jia Zhang,Xiaoxiang Cao,Zhichun Wang,Fei Wu,Chengyun Yao,Songqin Liu,Shizhang Ling,Hongping Xi 한국생체재료학회 2022 생체재료학회지 Vol.26 No.4

Background: Glioblastoma multiforme (GBM) is a fatal malignant primary brain tumor in adults. The therapeutic efficacy of chemotherapeutic drugs is limited due to the blood-brain barrier (BBB), poor drug targeting, and short biological half-lives. Multifunctional biomimetic nanodrugs have great potential to overcome these limitations of chemotherapeutic drugs. Methods: We synthesized and characterized a biomimetic nanodrug CMS/PEG-DOX-M. The CMS/PEG-DOX-M effectively and rapidly released DOX in U87 MG cells. Cell proliferation and apoptosis assays were examined by the MTT and TUNEL assays. The penetration of nanodrugs through the BBB and anti-tumor efficacy were investigated in the orthotopic glioblastoma xenograft models. Results: We showed that CMS/PEG-DOX-M inhibited cell proliferation of U87 MG cells and effectively induced cell apoptosis of U87 MG cells. Intracranial antitumor experiments showed that free DOX hardly penetrated the BBB, but CMS/PEG-DOX-M effectively reached the orthotopic ntracranial tumor through the BBB and significantly inhibited tumor growth. Immunofluorescence staining of orthotopic tumor tissue sections confirmed that nanodrugs promoted apoptosis of tumor cells. This study developed a multimodal nanodrug treatment system with the enhanced abilities of tumor-targeting, BBB penetration, and cancer-specific accumulation of chemotherapeutic drugs by combining chemotherapy and photothermal therapy. It can be used as a flexible and effective GBM treatment system and it may also be used for the treatment of other central nervous systems (CNS) tumors and extracranial tumors.

The Positive Association between Subclinical Hypothyroidism and Newly-Diagnosed Hypertension Is More Explicit in Female Individuals Younger than 65

Xichang Wang,Haoyu Wang,Li Yan,Lihui Yang,Yuanming Xue,Jing Yang,Yongli Yao,Xulei Tang,Nanwei Tong,Guixia Wang,Jinan Zhang,Youmin Wang,Jianming Ba,Bing Chen,Jianling Du,Lanjie He,Xiaoyang Lai,Yanbo Li 대한내분비학회 2021 Endocrinology and metabolism Vol.36 No.4

Background: Subclinical hypothyroidism (SCH) is the most common thyroid dysfunction, and its relationship with blood pressure(BP) has been controversial. The aim of the study was to analyze the association between SCH and newly-diagnosed hypertension. Methods: Based on data from the Thyroid disease, Iodine nutrition and Diabetes Epidemiology (TIDE) study, 49,433 euthyroid individuals and 7,719 SCH patients aged ≥18 years were enrolled. Patients with a history of hypertension or thyroid disease were excluded. SCH was determined by manufacturer reference range. Overall hypertension and stage 1 and 2 hypertension were diagnosedaccording to the guidelines issued by the American College of Cardiology/American Heart Association in 2017. Results: The prevalence of overall hypertension (48.7%), including stage 1 (28.9%) and 2 (19.8%) hypertension, increased significantly in SCH patients compared with euthyroid subjects. With elevated serum thyroid stimulating hormone (TSH) level, the hypertension prevalence also increased significantly from the euthyroid to different SCH subgroups, which was more profound in femalesor subjects aged <65 years. The age- and sex-specific regression analysis further demonstrated the same trends in the general population and in the 1:1 propensity matched population. Similarly, several BP components (i.e., systolic, diastolic, and mean arterial BP)were positively associated with TSH elevation, and regression analysis also confirmed that all BP components were closely relatedwith SCH in female subjects aged <65 years. Conclusion: The prevalence of hypertension increases for patients with SCH. SCH tends to be associated with hypertension and BPcomponents in females younger than 65 years.

Fine-grained Image Classification Using Combined DCNN and SVM

Yao Wang(왕야오),Woo Jin Jeong(정우진),Young Shik Moon(문영식) 대한전자공학회 2017 대한전자공학회 학술대회 Vol.2017 No.6

Fine-grained image classification is usually concerned with the same category of objects, for example different kinds of dogs such as Labrador and Golden Retriever. Since the fine-grained categories belong to the same main category, the gap between the categories is very small. These subtle gaps are easily covered by factors such as color, light and background, which leads to the difficulty of fine-grained image classification. In this paper, we propose a dogs breed recognizer that combined deep convolutional neural network with linear support vector machine to tackle fine-grained image classification problems. Deep convolutional neural network is used as a fixed feature extractor, and linear support vector machine is used as a classifier. The proposed method is tested on a dog dataset including 133 dog breeds and 8,351 images. Experimental result demonstrates that the classification accuracy of proposed method outperforms other conventional features methods by over 10 percentage point.