A number of U.S. coastal bridges have been destroyed by hurricanes, including three highway bridges in Mississippi and Louisiana during Hurricane Katrina (2005). This paper addresses three fundamental questions on the coastal bridge failures: (1) what were the hydrodynamic conditions near the failed bridge during the hurricane; (2) what was the cause of the bridge collapse; and (3) what was the magnitude of the hydrodynamic loading on the bridge under the extreme hurricane conditions. Guided by field observations of winds, waves, and water levels, two numerical models for storm surges and water waves are coupled to hindcast the hydrodynamic conditions. Fairly good agreement between the modeled and measured high watermarks and offshore wave heights is found, allowing an estimate of the surge and wave conditions near the bridges in nested domains with higher resolutions. The output of the coupled wave-surge models is utilized to determine the static buoyant force and wave forces on the bridge superstructure based on empirical equations derived from small-scale hydraulic tests for elevated decks used in the coastal and offshore industry. It is inferred that the bridge failure was caused by the wind waves accompanied by the storm surge, which raised the water level to an elevation where surface waves generated by strong winds over a relatively short fetch were able to strike the bridge superstructure. The storm waves produced both an uplift force and a horizontal force on the bridge decks. The magnitude of wave uplift force from individual waves exceeded the weight of the simple span bridge decks and the horizontal force overcame the resistance provided by the connections of the bridge decks to the pilings. The methodology for determining the hydrodynamic forcing on bridge decks can be used to produce a preliminary assessment of the vulnerability of existing coastal bridges in hurricane-prone areas.
Polyphenol oxidase(PPO)was extracted from Chinese Aloe with aoetone.The crude enzyme extract was fractionated with solid ammonium sulfate of 30%～90% saturation.After dialysis,the enzyme solution was purified by DEAE-Sephadex A-50 column chromatography.The enzyme was concentrated by PEG 6000.A13.28 fold purification of PPO was obtained.The result from polyacrylamide gelelectrophoresis of purified enzyme indicated that only one band was found using coomassie brilliant blue R250 stain.The molecular weight is about 54.1 KD.
Japonica rice was used as the female parent to cross with O.rufipogon.Fertile progenies were obtained through hybrid,backcross and selection.An easy way was designed to create new germplasm through distant cross between cultivated rice and wild rice,which would provide reference for the utilization of common wild rice.
This study employs land use and energy consumption data from Gansu Province spanning the years 2005 to 2020 and utilizes models to estimate carbon emissions and the corresponding carbon compensation values. The research calculated the carbon emissions and compensation for various administrative regions over different time periods, revealing the following insights: (1) There is a notable increasing trend in net carbon emissions due to land-use changes in Gansu Province, characterized by an initial swift rise, followed by a more gradual growth pattern. Construction land is identified as the primary contributor to carbon emissions, increasing from 26 million tons in 2005 to 55.3 million tons in 2020, which is an increase of 1.80 times; meanwhile, forested areas, as significant carbon sinks, show a slight increase in carbon absorption from 2.33 million tons in 2005 to 2.35 million tons in 2020. (2) The municipalities with high net carbon emissions are predominantly Lanzhou, Qingyang City, and Jiuquan City, which are marked by high levels of carbon emissions and low compensation rates. In contrast, regions with lower net carbon emissions are mainly found in the Gannan Tibetan Autonomous Prefecture, where emissions are minimal and compensation rates are relatively high. A similarity in the spatial distribution patterns of both net carbon emission intensity and total net carbon emissions is observed among these cities. Alterations in land use have a significant impact on regional carbon emissions. Investigating the spatiotemporal variations of land-use change and carbon compensation in Gansu Province is essential for comprehending the dynamics of regional carbon emissions, developing effective emission reduction strategies, and fostering low-carbon development.
왕고들빼기(선향 품종)을 4주 간격으로 파종하여, 4주 동안 재배하여 어린잎(초장 10cm 이하)과 8주 동안 재 배하여 성체(초장이 20±5cm) 상태에서 수확하였다. 수확 직후 조사한 호흡률과 에틸렌 발생률은 모두 어린잎이 성체보다 높았으며, DPPH 라디컬 소거능도 성체에 비 해 어린잎에서 높았다. 잎의 L*, a*, b*값은 어린잎과 성 체가 유의적인 차이를 보이지 않았고 엽록소 함량은 성 체에서 높았다. 왕고들빼기 성체와 어린잎을 미세천공 필름으로 포장하여 2°C, 8°C, 및 20°C에서 저장하였을 때, 저장온도가 높을수록 생체중 감소율이 높았으며, 2°C와 8°C에서는 성체의 생체중 감소율이 낮았다. 저장 중 패널테스트를 통해 진행한 외관상 품질도 저장온도가 높을수록 빠르게 나빠졌다. 또한 외관상 품질이 3점을 유지되었던 기간으로 계산한 저장수명은 성체가 2°C에 서는 1.6일, 8°C에서는 1.4일, 그리고 20°C에서는 1.5일 어린잎보다 더 길었다. 저장 종료일 조사한 포장 내 산 소 및 이산화탄소 농도는 대기 중 농도와 유사한 수준 이었다. 저장 종료일의 엽록소 함량은 저장온도가 낮을 수록 높게 유지되었고, 패널테스트로 조사한 이취는 어 린잎에서 더 높은 수준이었다.
Aim To examine G.Green′s two papers on water waves and their influence.Methods Using comprehensive analysis and comparing the original literatures and research materials.Results Green solved long wave problem practically,and gave the first mathematical explanation of solitary waves.Conclusion Green′s long-wave approximation,analysis of the effects of slow variations,and taking account of waves moving in one direction only gave exemplary models in the research of water waves,including solitary waves.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)
