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Repellent effect of guava leaf volatiles on settlement of adults of citrus psylla, Diaphorina.c.tri Kuwayama, on citrus

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Insect Science 2010年第1期17卷 39-45页

作者： Syed Muhammad Zaka Xin-Nian Zeng Paul Holford george Andrew charles beattie Key Laboratory of Natural Pesticide and chemical Biology of the Ministry of Education South China Agricultural University Guangzhou China centre for Plant and Food Science University of Western Sydney Locked Bag 1797 Pennth South DC New South Wales 1797 Australia

The Asiatic citrus psyllid （Diaphorina.c.rri Kuwayama [Hemiptera： Sternorrhyncha： Psyllidae] is a vector ofhuanglongbing （citrus greening）, a devastating disease of citrus caused by phloem-limited bacteria. Growing guava （Psidium guajava） as an intercrop appears to be a successful means of reducing psyllid numbers within citrus orchards; however, the mechanism by which such a reduction is achieved is unknown. To determine the repellent effect of guava leaf and factors attributed to this activity, responses of adult psyllids to guava leaf and its odor were evaluated in cage tests and Y-tube olfactometer test. The results showed that guava leaf possessed a repellent effect against the adult citrus psyllids. Fewer psyllids were found on citrus leaves in the presence of guava foliage than in its absence. Young and old guava leaf showed equal repellent activity. By covering the guava shoots with net cloth, it was revealed that the repellent effect of guava leaf against adult psyllids on citrus was attributed to the volatile compounds, rather than physical factors. The olfactometer response of adult psyllids to guava leaf odor was dosage-dependent. Between guava odor and control, only 35.00%, 25.00% and 16.25% of the psyllids moved toward guava odor when presented with 5.0, 10.0 and 15.0 g of guava shoots, respectively. The olfactometer experiments also showed that both male and female psyllids responded similarly to the guava leaf odor.

关键词： Asiatic citrus psyllid huanglongbing (HLB) insect behavior Psidium guajava volatile compounds

Traveling wave effect on the seismic response of a steel a.c. bridge subjected to near fault ground motions

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Earthquake Engineering and Engineering Vibration 2007年第3期6卷 245-257页

作者：徐艳 george c Lee McEER University at BuffaloNY 14260 USA Department of Bridge EngineeringTongji UniversityShanghai 200092China McEER University at BuffaloNY 14260USA

In the 1990s, several major earthquakes occurred throughout the world, with a.c.mmon observation that near fault ground motion （NFGM） characteristics had a distinct impact on causing damage to civil engineering structures that could not be predicted by using far field ground motions. Since then, seismic responses of structures under NFGMs have been extensively examined, with most of the studies focusing on structures with relatively short fundamental periods, where the traveling wave effect does not need to be considered. However, for long span bridges, especially a.c. bridges, the traveling wave （only time delay considered） effect may be very distinct and is therefore important. In this paper, the results from a.c.se study on the seismic response of a steel a.c. bridge under selected NFGMs is presented by considering the traveling wave effect with variable apparent velocities. The effects of fling step and long period pulses of NFGMs on the seismic responses of the a.c. bridge are also discussed.

关键词： traveling wave effect a.c. bridge near fault ground motion fling step long period pulses

Time derivative of earthquake a.c.leration

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Earthquake Engineering and Engineering Vibration 2005年第1期4卷 1-16页

作者： george c. Lee Multidisciplinary center for Earthquake Engineering Resea.c. University at Buffalo Buffalo NY 14261-0025 USAProfessor

Unlike a.c.leration, velocity, and displacement, the time derivative ofa.c.leration (TDoA) of ground motion has not been extensively studied. In this paper, the basiccharacteristics of TDoA are evaluated based on records from the 1999 chi-chi, earthquake (Mw 7.6)and one of its aftershocks (Mw 6.2). It is found that the maximum TDoA at a free-field station wasover 31,200 cm/s3 (31.8 g/s); and the duration of 'strong' TDoA, between the first and the last timepoints exceeding 2,000 cm/s3 (2 g/s), was almost one minute near the epicenter area. Since groundTDoA sensors are not commonly available, the time series are ca.c.lated by direct numericaldifferentiation of a.c.leration time series. Relative error analysis shows that the error isnon-transitive and total error is within 4%. The density function of TDoA amplitude, frequencycontent and spatial distribution of peak ground jerk (PGJ) are evaluated. The study also includesexamination of some TDoA responses from a seven-story building and comparison of ground TDoA withthe limit TDoA used in the transportation industry for ride comfort. Some potential impacts of TDoAon humans have also been reviewed.

关键词： time derivation of a.c.leration peak ground jerk a.c.leration time series earthquake ground motion earthquake effect on human activities

Urban china in Transformation:Hybrid Economy,Juxtaposed Space,and New Testing Ground for Geographical Enquiries

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chinese Geographical Science 2011年第1期21卷 1-16页

作者： george c S LIN Department of Geography University of Hong Kong

History has brought us into a significant moment when the majority of the human kind has taken up resi-dence in urban settlements. The focus of global urbanization has shifted to the developing world and the center of manufacturing is no longer confined to the Global North. This paper provides a periodical assessment of the current status of china's urban transformation in the global context of a shifting emphasis of industrialization and urbaniza-tion. china's phenomenal urban transformation deserves a special attention not only because of its unparalleled scale and speed but also because of its distinct trajectory of growth that does not conform to normal theoretical ex-pectations. The results of assessment revealed an urban economy with remarkable hybridity, a society that is in-creasingly stratified, polarized, and segregated, and a juxtaposed urban space undergoing restless and pervasive transformation. A decentering world should entail a decentering knowledge production. a.c.itical reflection upon the chinese patterns and processes of urban transformation has identified 4 main issues with great potentials for inno-vative knowledge production, namely: 1) privatization and economic development; 2) state, society, and space; 3) urbanization of capital, labor, and land; and 4) the environment and chinese political ecology. The paper closes with the remark that a rapidly transforming urban china has presented itself as a fertile and resourceful testing ground for critical and innovative geographic enquiries.

关键词： urban geography urbanization chinese cities political economy china

Towards establishing practical multi-hazard bridge design limit states

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Earthquake Engineering and Engineering Vibration 2013年第3期12卷 333-340页

作者： Zach Liang george c.Lee Department of Mechanical and Aerospace Engineering Unidersity at Buffalo Depart of civil Structural and Environmental Engineering University at Buffalo

In the U.S., the current Load and Resista.c. Factor Design （LRFD） Specifications for highway bridges is a reliability-based formulation that considers failure probabilities of bridge components due to the actions of typical dead load and frequent vehicular loads. Various extreme load effects, such as earthquake and vessel collision, are on the same reliability-based platform. Since these extreme loads are time variables, combining them with not considered frequent. non- extreme loads is a significant challenge. The number of design limit state equations based on these failure probabilities can be unrealistically large and unnecessary from the view point of practical applications. Based on the opinion of AASHTO State Bridge Engineers, many load combinations are insignificant in their states. This paper describes the formulation of a.c.iterion to include only the necessary load combinations to establish the design limit states. This criterion is established by examining the total failure probabilities for all possible time-invariant and time varying load combinations and breaking them down into partial terms. Then, important load combinations can be readily determined quantitatively,

关键词： multi-hazards load and resista.c. factor design re.liability based bridge design specifications design limit state equations

Towards multiple hazard resilient bridges:a methodology for modeling frequent and infrequent time-varying loads Part I,comprehensive reliability and partial failure probabilities

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Earthquake Engineering and Engineering Vibration 2012年第3期11卷 293-301页

作者： Zach Liang george c.Lee Department of Mechanical and Aerospace Engineering University at Buffalo Department of civil Structural and Environmental EngineeringUniversity at Buffalo

The current AASHTO load and resista.c. factor design （LRFD） guidelines are formulated based on bridge reliability, which interprets traditional design safety factors into more rigorously deduced factors based on the theory of probability. This is a major adva.c.ment in bridge design specifications. However, LRFD is only calibrated for dead and live loads. In cases when extreme loads are significant, they need to be individually assessed. combining regular loads with extreme loads has been a major challenge, mainly because the extreme loads are time variables and cannot be directly combined with time invariant loads to formulate the probability of structural failure. To overcome these difficulties, this paper suggests a methodology of comprehensive reliability, by introducing the concept of partial failure probability to separate the loads so that each individual load combination under a.c.rtain condition can be approximated as time invariant. Based on these conditions, the extreme loads （also referred to as multiple hazard or MH loads） can be broken down into single effects. In Part II of this paper, a further breakdown of these conditional occurrence probabilities into pure conditions is discussed by using a live truck and earthquake loads on a bridge as an example. There are three major steps in establishing load factors from MH load distributions：（1） formulate the failure probabilities; （2） normalize various load distributions; and （3） establish design limit state equations. This paper describes the formulation of the failure probabilities of single and combined loads.

关键词： multiple hazards bridge probability-based design comprehensive reliability partial failure probability

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From the editors:special issue announcement

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Earthquake Engineering and Engineering Vibration 2009年第2期8卷 251-261页

作者： Wang Zhiqiang george c. Lee Department of Bridge Engineering Tongji University Shanghai 200092 China Department of civil Structural and Environmental Engineering University at Buffalo State University of New York USA

a.c.mparative study of selected bridge damage due to the Wenchuan, Northridge, Loma Prieta and San Fernando earthquakes is described in this paper. Typical ground motion effects considered include large ground fault displacement, liquefaction, landslide, and strong ground shaking. Issues related to falling spans, inadequate detailing for structural ductility and complex bridge configurations are discussed within the context of the recent seismic design codes of china and the US. A significant lesson learned from the Great Wenchuan earthquake, far beyond the opportunities to improve the seismic design provisions for bridges, is articulated.

关键词： bridge damage Wenchuan earthquake Northridge earthquake Loma Prieta earthquake San Fernandoearthquake ground motion liquefaction landslide

Bridge pier failure probabilities under combined hazard effects of scour, truck and earthquake. Part Ⅰ: occurrence probabilities

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Earthquake Engineering and Engineering Vibration 2013年第2期12卷 229-240页

作者： Zach Liang george c. Lee Department of Mechanical and Aerospace Engineering Unidersity at Buffalo Depart of civil Structural and Environmental EngineeringUniversity at Buffalo

In many regions of the world, a bridge will experience multiple extreme hazards during its expected service life. The current American Association of State Highway and Transportation Officials （AASHTO） load and resista.c. factor design （LRFD） specifications are formulated based on failure probabilities, which are fully calibrated for dead load and nonextreme live loads. Design against earthquake loads is established separately. Design against scour effect is also formulated separately by using the concept of capacity reduction （or increased scour depth）. Furthermore, scour effect cannot be linked directly to an LRFD limit state equation, because the latter is formulated using force-based analysis. This paper （in two parts） presents a probability-based procedure to estimate the combined hazard effects on bridges due to truck, earthquake and scour, by treating the effect of scour as an equivalent load effect so that it can be included in reliability-based bridge failure ca.c.lations. In Part I of this series, the general principle of treating the scour depth as an equivalent load effect is presented. The individual and combined partial failure probabilities due to truck, earthquake and scour effects are described. To explain the method of including non-force-based natural hazards effects, two types of common scour failures are considered. In Part 11, the corresponding bridge failure probability, the occurrence of scour as well as simultaneously having both truck load and equivalent scour load are quantitatively discussed.

关键词： multi-hazards load and resista.c. factor design bridge scour

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Asymptotic Properties of a Modified Semi-Parametric MLE in Linear Regression with Right-censored Data

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Acta Mathematica Sinica,English Series 2002年第2期18卷 405-416页

作者： WONG george Y.c. Strang ca.c.r Prevention center.428 E 72nd Street.New York.NY 10021.USA

consider a linear regression model Y=β'X+*** Y may be right censored and the cdf F+o of e is *** show that a modified semi-parametric *** by .is strongly consistent under certain regularity *** F_o is discontinuous,then P(≠βi.o.)=0, which means that P(=βif the sample size is large)=*** latter property has not been reported for the existing *** contrast,most estimators,such as the Buckley-James estimator and M-estimators .satisfy that P(≠βi.o.)=1.

关键词： consistency Super-efficiency Semi-parametric MLE