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.

Antioxidant and α-Glucosidase Inhibitory Activities of the Extract from Sparganium stoloniferum Buch.-Ham. Root and Its Constituent Compounds

Ming Lu Xu,Lan Wang,Jian He Hu,Myeong-Hyeon Wang 한국식품영양과학회 2009 Preventive Nutrition and Food Science Vol.14 No.4

Three compounds, vanillic acid, p-hydroxylcinnamic acid, p-hydroxybenzaldehyde have been isolated from the ethylacetate extract of Sparganium stoloniferum Buch.-Ham roots using silica gel open column chromatography, preparative thin-layer chromatography (pTLC) and reverse phase high performance liquid chromatography. The structures of the compounds were established on the basis of IR, extensive 1D NMR, and MS analyses. The ethylacetate (EtOAc) extract, vanillic acid, and p-hydroxybenzaldehyde showed α-glucosidase inhibition activity of 72.71%, 20.13%, and 30.42%, at the concentration of 10 ㎍/mL, respectively. The EtOAc extract exhibited strong antioxidant activity with an IC50 value of 24.37 ㎍/mL against DPPH radical scavenging activity, the vanillic acid, p-hydroxylcinnamic acid, and p-hydroxybenzaldehyde with an IC50 value of 2.10 μM, 1.59 μM, and 2.72 μM against DPPH, respectively.

The boundedness of some bilinear singular integral operators on Besov spaces

Ming Xu 대한수학회 2006 대한수학회지 Vol.43 No.2

In this paper we weaken the kernel conditions of bilinear Calder$\acute{o}$n-Zygmund operators and prove boundedness on Besov spaces.

THE BOUNDEDNESS OF SOME BILINEAR SINGULAR INTEGRAL OPERATORS ON BESOV SPACES

Xu Ming Korean Mathematical Society 2006 대한수학회지 Vol.43 No.2

In this paper we weaken the kernel conditions of bilinear Calderon-Zygmund operators and prove boundedness on Besov spaces.

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.

Synthesis and characterization of maleated polyethylene/clay nanocomposites

Ming Zhe Xu,Ki Hyun Wang,In Jae Chung 한국고분자학회 2001 한국고분자학회 학술대회 연구논문 초록집 Vol.2001 No.10

A New Stilbene Glucoside from the Roots of Polygonum multiflorum Thunb.

Ming-Lu Xu,Ming Shan Zheng,Yeon-Kyong Lee,문동철,Chong-Soon Lee,우미희,정병선,Eung Seok Lee,장영동,장현욱,이승호,손종근 대한약학회 2006 Archives of Pharmacal Research Vol.29 No.11

One new stilbene glucoside (6), along with five known compounds (1-5), were isolated from the roots of Polygonum multiflorum Thumb., and their chemical structures established based on physicochemical and spectroscopic data. Of the compounds, compound 3 showed DNA topoisomerase I and II inhibitory activities.

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

Xu, Ming-Lu,Li, Gao,Moon, Dong-Cheol,Lee, Chong-Soon,Woo, Mi-Hee,Lee, Eung-Seok,Jahng, Yurng-Dong,Chang, Hyeun-Wook,Lee, Seung-Ho,Son, Jong-Keun The Pharmaceutical Society of Korea 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 $20\;{\mu}M$, respectively).

Distinctions Between Clinicopathological Factors and Prognosis of Alpha-fetoprotein Negative and Positive Hepatocelluar Carcinoma Patients

Xu, Jia,Liu, Chang,Zhou, Lei,Tian, Feng,Tai, Ming-Hui,Wei, Ji-Chao,Qu, Kai,Meng, Fan-Di,Zhang, Ling-Qiang,Wang, Zhi-Xin,Zhang, Jing-Yao,Chang, Hu-Lin,Liu, Si-Nan,Xu, Xin-Shen,Song, Yan-Zhou,Liu, Jun,Z Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.2

Serum alpha-fetoprotein (AFP) is a significant marker for clinical diagnosis and prognosis evaluation in hepatocellular carcinoma (HCC) patients. However, some proportion of liver cancer patients are AFP-negative (AFP ${\leq}$20ng/ml). In order to study the differences between clinicopathological factors and prognosis of alpha-fetoprotein negative and positive patients, a total of 114 cases (41 AFP-negative and 73 AFP-positive) were selected for our research. By systematically statistical analysis, the results demonstrated that compared with AFP-negative patients, AFP-positive examples were more likely to feature cirrhosis nodules, non-complete neoplasm capsules, and a poor Edmondson-steiner grade. Furthermore, AFP-negative patients demonstrated a favorable long-term prognosis. By univariate analysis and multivariate analysis with Cox's proportional hazards model, multiple tumors were found to be independent risk factors for worse survival of AFP negative patients; however, less tumor-free margins, multiple tumors and Edmondson-steiner grades III/IV, proved to be independent risk factors leading to a poor prognosis of AFP positive cases. Finally, we can infer that high levels of AFP signify a highly malignant tumor and unfavorable prognosis.