Amplitude dependency of damping of tall structures by the random decrement technique

An Xu,Zhuangning Xie,Ming Gu,Jiurong Wu 한국풍공학회 2015 Wind and Structures, An International Journal (WAS Vol.21 No.2

This study focuses on the amplitude dependency of damping of tall structures by the random decrement technique (RDT). Many researchers have adopted RDT to establish the amplitude dependency of damping ratios in super-tall buildings under strong wind loads. In this study, a series of simulated examples were analyzed to examine the reliability of this method. Results show that damping ratios increase as vibration amplitudes increase in several cases; however, the damping ratios in the simulated signals were preset as constants. This finding reveals that this method and the derived amplitude-dependent damping ratio characteristics are unreliable. Moreover, this method would obviously yield misleading results if the simulated signals contain Gaussian white noise. Full-scale measurements on a super-tall building were conducted during four typhoons, and the recorded data were analyzed to observe the amplitude dependency of damping ratio. Relatively wide scatter is observed in the resulting damping ratios, and the damping ratios do not appear to have an obvious nonlinear relationship with vibration amplitude. Numerical simulation and field measurement results indicate that the widely-used method for establishing the amplitude-dependent damping characteristics of super-tall buildings and the conclusions derived from it might be questionable at the least. More field-measured data must be collected under strong wind loads, and the damping characteristics of super-tall buildings should be investigated further.

중국조선족집거구문제에 대한 사고

허명철 전남대학교 아시아태평양지역연구소 2000 아시아태평양지역연구 Vol.3 No.1

21세기 새로운 민족적 비전을 꿈꾸고 있는 중국조선족사회는 현재 인구감소와 인구류동에 의한 기존의 집거구해체와 이에 따라 나타나고 있는 사회성적인 문제들로 하여 고민을 겪고 있다. 집거구해체는 민족교육의 위기를 초래하게 되고 민족언어와 문자를 사용할 수 있는 문화공간을 좁아지게 하는바 이는 결국 민족동화를 가속화하게 되며 나중에는 민족정체성 유지에도 큰 영향을 미치게 된다는 것이 일부 학자들의 주장이다. 그렇다면 집거구해체를 어떤 입장에서 평가해야 하고 이에 따라 초래되고 있는 문제들은 또 어떤 시각에서 풀어나가야 하는가? 이 문제어 대해서 우리는 기존의 집거구가 형성되고 보존되어 올 수 있었던 원인들을 검토해 보고 그 기초상에서 응당 시대성, 민족성, 발전성적인 시각에서 그 답안을 모색해야 한다. 여기에서 우선 중요한 것은 우리들의 의식전환이다. 오늘날 우리민족의 진로는 농촌에 있는 것이 아니라 도시어 있으며 현대문명에로의 이행에 있는 것이다. 우리는 연해개방도시들에 새로 일떠서고 있는 새로운 집거지 즉 "코리아타운'에 민족의 미래를 기탁하고 기존의 농촌집거구건설을 잘하여 질적으로 제고시키는 한편 보다 많은 정력을 도시집거구건설에 몰부어야 하고 새로운 집거구형성과정에서 나타나고 있는 산재지구에서의 민족교육실시, 민족문자와 언어보급, 민족정체성 보존등 문제들의 해결에 주력해야 한다. 그러고 이러한 문제점 해결에 있어서 그 시야를 보다 넓혀 세계화적 추세와 정보화문명에 입각점을 두어야 한다. In the 21st century, the Chinese-Korean(Korean minority in china) who are striving for a leap in their ethnical improvement is now vexed by population decline and migration which are disintegrating the old Chinese-Korean community. Some scholars believe that the disintegration of Chinese-Korean community will lead to a series of problems: a crisis of ethnic education, a reduction of the cultural space where the Chinese-Koreans can learn and use their language, ethic assimilation, and consequently disintegration of Chinese-Korean community. How can we solve the Problem on the disintegration of Chinese-Korean community? We should reconsider the reasons why Chinese-Korean community can de formed and developed. In addition to that, We should seek the answer to this problem from the perspective of time, ethology and development. thus, the development of Chinese-Korean. The approach towards the development of Chinese-Korean does not rely on the rural area, but on the more developed and civalized urban area.. the future of the Chinese-Korean lies on the "Korean Town", i · e · the new Chinese-Korean communities in the new opening cities along the east coast line of China. In addition to improve the qualits of the old Chinese-Korean communities which mainly inhabited in the hew Chinese-Korean communities which considerately live in the urban cities. During the course of the formation of the hew Chinese-Korean communities in the eastern urban area of China, we should put great effort on the ethnic education, popularization of Korean language, and maintenance of the integrity of the Chinese-Korean community. Furthermore, we should enlarge our perspective and focus our attention at the trends of globalization and informationalized civilization in the world.

Endoscopic Therapy for Pancreatic Fluid Collections: A Definitive Management Using a Dedicated Algorithm

Ming Ming Xu,Iman Andalib,Aleksey Novikov,Enad Dawod,Moamen Gabr,Monica Gaidhane,Amy Tyberg,Michel Kahaleh 대한소화기내시경학회 2020 Clinical Endoscopy Vol.53 No.3

Background/Aims: Endoscopic ultrasonography (EUS)-guided drainage is the preferred approach for infected or symptomaticpancreatic fluid collections (PFCs). Here, we developed an algorithm for the management of pancreatitis complicated by PFCs andreport on its effcacy and safety. Methods: Between September 2011 and October 2017, patients were prospectively managed according to the algorithm. PFCs wereclassified as poorly organized fluid collections (POFCs), pancreatic pseudocysts (PPs), or walled-off pancreatic necrosis (WOPN). Clinical success was defined as a decrease in PFC size by ≥50% of the maximal diameter or to ≤2 cm. Results: A total of 108 patients (62% male; mean age, 53 years) were included: 13 had POFCs, 43 had PPs, and 52 had WOPN. Seventytwopatients (66%) required a pancreatic duct (PD) stent, whereas 65 (60%) received enteral feeding. A total of 103 (95%) patientsachieved clinical success. Eight patients experienced complications including bleeding (n=6) and surgical intervention (n=2). Patientswith enteral feeding were 3.4 times more likely to achieve resolution within 60 days (p=0.0421), whereas those with PD stenting was fivetimes more likely to achieve resolution within 90 days (p=0.0069). Conclusions: A high PFC resolution rate can be achieved when a dedicated algorithm encompassing EUS-guided drainage, PDstenting, and early enteral feeding is adopted.

Low Expression of the FoxO4 Gene may Contribute to the Phenomenon of EMT in Non-small Cell Lung Cancer

Xu, Ming-Ming,Mao, Guo-Xin,Liu, Jian,Li, Jian-Chao,Huang, Hua,Liu, Yi-Fei,Liu, Jun-Hua Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.9

Because of its importance in tumor invasion and metastasis, the epithelial-mesenchymal transition (EMT) has become a research focus in the field of cancer. Recently, evidence has been presented that FoxO4 might be involved in EMT. Our study aimed to detect the expression of FoxO4, E-cadherin and vimentin in non-small cell lung cancers (NSCLCs). We also investigated clinical features and their correlations with the markers. In our study, FoxO4, E-cadherin and vimentin were assessed by immunohistochemistry in a tissue microarray (TMA) containing 150 cases of NSCLC. In addition, the expression level of FoxO4 protein was determined by Western blotting. The percentages of FoxO4, E-cadherin and vimentin positive expression in NSCLCs were 42.7%, 38.7% and 55.3%, respectively. Immunoreactivity of FoxO4 was low in NSCLC when compared with paired normal lung tissues. There were significant correlations between FoxO4 and TNM stage (P<0.001), histological differentiation (P=0.004) and lymph node metastasis (P<0.001), but no significant links with age (P=0.323), gender (P=0.410), tumor size (P=0.084), smoking status (P=0.721) and histological type (P=0.281). Our study showed that low expression of FoxO4 correlated with decreased expression of E-cadherin and elevated expression of vimentin. Cox regression analysis indicated FoxO4 to be an independent prognostic factor in NSCLC (P=0.046). These data suggested that FoxO4 might inhibit the process of EMT in NSCLC, and might therefore be a target for therapy.

Reverse Endoscopic Ultrasound-Guided Gastrojejunostomy for the Treatment of Superior Mesenteric Artery Syndrome: A New Concept

Ming-ming Xu,Enad Dawod,Monica Gaidhane,Amy Tyberg,Michel Kahaleh 대한소화기내시경학회 2020 Clinical Endoscopy Vol.53 No.1

Superior mesenteric artery syndrome (SMAS) causes compression and partial or complete obstruction of the duodenum, resulting inabdominal pain, nausea, vomiting, and weight loss. If conservative therapy fails, the patient is typically referred for enteral feeding orlaparoscopic gastrojejunostomy. The last few years have seen increasing use of endoscopic ultrasound-guided gastrojejunostomy (EUS-GJ) for gastric obstructionindications. EUS-GJ involves the creation of a gastric bypass via an echoendoscope in cases in which the small intestine can bepunctured under ultrasonographic visualization, resulting in an incision-free, effcient, and safe procedure. In this case report, we present the first case of SMAS treated using a reverse EUS-GJ, and describe the steps and advantages of theprocedure in this particular case.

Antioxidant Activities and Related Polyphenolic Constituents of the Methanol Extract Fractions from Broussonetia papyrifera Stem Bark and Wood

Ming-Lu Xu,Lan Wang,Jian-He Hu,이석기,왕명현 한국식품과학회 2010 Food Science and Biotechnology Vol.19 No.3

Broussonetia papyrifera radix, fruits, leaves,and stems exhibit antioxidant, antinociceptive, antityrosinase,anti-inflammatory, and antiplatelet activities. However,study of the antioxidant activity of stem bark has been limited. In this work the antioxidant activity of stem bark and wood extracts were compared using different methods,and their phenolic constituents were analyzed. The bark ethyl acetate fraction exhibited the highest 2,2-diphenyl-2-picrylhydrazyl hydrate (DPPH) radical, hydroxyl radical scavenging activity, and the highest total phenolic and flavonoid contents. Both bark and wood n-butanol fractions showed stronger superoxide anion radical scavenging activity and reducing potential than other fractions. The bark and wood hexane fraction provided the highest level of ion chelating power. The high performance liquid chromatography (HPLC) analysis reveals there are more phenolic compounds in bark than in wood. These findings suggest that bark exhibits a higher antioxidant capacity than wood and that ethyl acetate and n-butanol fractions of B. papyrifera bark are potential natural resources for pharmacology of functional foods.

Synthesis and Properties of Exfoliated Poly(methyl methacrylate-co- acrylonitrile)/Clay Nanocomposites via Emulsion Polymerization

Ming Zhe Xu,Yeong Suk Choi,Ki Hyun Wang,Jong Hyun Kim,In Jae Chung 한국고분자학회 2003 Macromolecular Research Vol.11 No.6

Cytotoxicity and DNA Topoisomerase Inhibitory Activity of Constituents Isolated from the Fruits of Evodia officinalis

Ming-Lu Xu,Gao Li,문동철,Chong-Soon Lee,우미희,Eung Seok Lee,장영동,장현욱,이승호,손종근 대한약학회 2006 Archives of Pharmacal Research Vol.29 No.7

Four alkaloids (1-4), three quinolone alkaloids (5-7), and three flavanoid glucosides (8-10) were isolated from the fruits of Evodia officinalis Dode, and their structures were determined from chemical and spectral data. Compounds, 3, 8, 9 and 10 were isolated from this plant for the first time. Of these compounds, 1-3 and 5-7 exhibited moderate cytotoxicities against cultured human colon carcinoma (HT-29), human breast carcinoma (MCF-7), and human hepatoblastoma (HepG-2). Compound 8 showed strong inhibitory effects on DNA topoisomerases I and II (70 and 96% inhibition at a concentration of 20 µM, respectively).

A Case Study on the Payment Prohibition from the Fraud of Letter of Credit (L/C) in Connection with Chinese Enterprises

Xu Ming,Shim Sang-Ryul 한국무역학회 2018 한국무역학회 국제학술대회 Vol.2018 No.7

Collapse Behaviours of Stiffened Panels Under Longitudinal Compression Considering Heating and Cooling Processes

Ming Cai Xu,Zhao Jun Song,Jin Pan 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.4

The fi re accidents casually happen during operation of ship, which would infl uence the load carrying capacity of stiff ened panel of ship structures due to the thermal load. The present paper aims to understand the infl uence of thermal loads on the collapse behaviour of stiff ened panels under longitudinal compressive load. Considering the heating and cooling down processes, the collapse behaviours of the stiff ened panels under combined in-plane displacement and heat loads representative of fi re accident are simulated in the FE (fi nite element) analysis herein. Firstly, the thermal load is considered to investigate the stress state of the stiff ened panels during heating and cooling processes. It is found that the stiff ened panels would collapse during thermal loads for the structure with large heated zone. After that, the longitudinal compression loads are applied to assess the collapse strength of the stiff ened panels. The parametric studies including diff erent geometrical dimensions and areas of heat zone are performed in detail to quantify the eff ects of heat loads on the collapse behaviours of stiff ened panels. It is found that the expansion could produce biaxial stress state that depends on not only in-plane stiff ness but also collapse modes, and for stiff ened panels with various heated area the cooling down to room temperature induce similar ultimate strength to that without considering heat loads.