In order to quickly explore the quality of cut-off wall in dams, a new method of high-density seismic image was adopted and estimated by model and in-situ wall tests.The vibration exciter was employed and several para...In order to quickly explore the quality of cut-off wall in dams, a new method of high-density seismic image was adopted and estimated by model and in-situ wall tests.The vibration exciter was employed and several parameters such as hypocentral distance, length of signal record and sampling space in signal collection were determined, which are 8 m, 0.25 ms and 128 ms respectively. Through time and frequency field signal analyses, it is concluded that, the smaller arrival times of reflected longitudinal and surface waves, and the higher their main frequencies, the higher the strength of the wall, vice versa. Accordingly the construction quality of the wall can be evaluated quickly by high-density seismic image.展开更多
The monumental Studies to Fathom Principles(Qiongli xue窮理學;1683)by Ferdinand Verbiest S.J.(Nan Huairen南懷仁,1623–1688)was never printed,and its exact content is not known.A section of the only extant,though incom...The monumental Studies to Fathom Principles(Qiongli xue窮理學;1683)by Ferdinand Verbiest S.J.(Nan Huairen南懷仁,1623–1688)was never printed,and its exact content is not known.A section of the only extant,though incomplete,manuscript deals with fluvial flood prevention and river control measures,a subject that until then had not cropped up in any Chinese-language work of the Jesuits.In this section,Verbiest not only described the already well-known Aristotelian theory of the origin of rivers,but also introduced to China new scientific propositions,concepts,and numerical examples originating from the seminal Renaissance work Della misura dell’acque correnti(Of the Mensuration of Running Waters;1628)by Benedetto Castelli(1578–1643).In addition,Verbiest presented to his readers some noteworthy examples of pertinent Western achievements such as the pound-lock with miter gate,and he provided them with a simple economic analysis of flood control options.The significance and possible influence of Verbiest’s text on further developments in Chinese approaches to water engineering are discussed,highlighting a hitherto largely disregarded facet of Western science and technology transfer in the field of river hydraulics and flood management.展开更多
For the assessment of the impact of future climate change on the hydrologic regime and water resources of Peninsular Malaysia, it is necessary to downscale the climate change simulations of a coarse scale General Circ...For the assessment of the impact of future climate change on the hydrologic regime and water resources of Peninsular Malaysia, it is necessary to downscale the climate change simulations of a coarse scale General Circulation Model to the region of Peninsular Malaysia at fine grid resolution. This paper presents a desktop review of the state of climate change parameters, namely rainfall and river flow over the Peninsular Malaysia for the 2041-2050 projection period. Analysis of the results from the models shows there will be a substantial increase in mean monthly precipitation over the North East Coastal region from historical 259.5 mm to 281.5 mm, from 289.0 mm to 299.0 mm and 221.8 mm to 239.5 mm over Terengganu and Kelantan, respectively. Meanwhile, for river flow projection, it will be an expected increase in interannual and intraseasonal variability with increased hydrologic extremes （higher high flows, and lower low flows） at Kelantan, Pahang, Terengganu, and Kedah watersheds in the future.展开更多
Due to limited in situ data and diagnostic numerical models, the summer circulation structure and formation mechanism in the Beibu Gulf have always been in controversy in the past 50 years. Therefore, a new three-dime...Due to limited in situ data and diagnostic numerical models, the summer circulation structure and formation mechanism in the Beibu Gulf have always been in controversy in the past 50 years. Therefore, a new three-dimensional hindcast model was built within the northwestern South China Sea(SCS), forced with the daily averaged wind, heat flux, lateral flux, as well as tidal harmonic and eight major rivers discharges. And the east boundary was set up far away off the Qiongzhou Strait(QS). Lastly, the model results were consistent with not only the synchronous observation data from the project 908 but also the historical observed data. As a result, the summer circulation structure was revealed that the southern Gulf was occupied by an anticyclonic eddy whereas the northern Gulf was dominated by a cyclonic gyre. Although the circulation major structure was stable, its area and strength had yearly and monthly oscillation. The other three sensitive experiments indicated that the circulations in the southern and northern Gulf were driven by the SCS circulation and monsoon wind, respectively. After the theoretical analysis of the potential vorticity budget, it was further revealed the circulation in the northern Gulf was driven by the positive wind stress curl in summer. Besides, the river discharge was also significant as the vertical circulation had two layer structures outside the mouth of the Red River. Generally, this work calls for the further research on other subjects, such as ocean biogeochemical or marine fisheries.展开更多
文摘In order to quickly explore the quality of cut-off wall in dams, a new method of high-density seismic image was adopted and estimated by model and in-situ wall tests.The vibration exciter was employed and several parameters such as hypocentral distance, length of signal record and sampling space in signal collection were determined, which are 8 m, 0.25 ms and 128 ms respectively. Through time and frequency field signal analyses, it is concluded that, the smaller arrival times of reflected longitudinal and surface waves, and the higher their main frequencies, the higher the strength of the wall, vice versa. Accordingly the construction quality of the wall can be evaluated quickly by high-density seismic image.
基金funded by the German Research Foundation(DFG)for the years 2018 to 2022
文摘The monumental Studies to Fathom Principles(Qiongli xue窮理學;1683)by Ferdinand Verbiest S.J.(Nan Huairen南懷仁,1623–1688)was never printed,and its exact content is not known.A section of the only extant,though incomplete,manuscript deals with fluvial flood prevention and river control measures,a subject that until then had not cropped up in any Chinese-language work of the Jesuits.In this section,Verbiest not only described the already well-known Aristotelian theory of the origin of rivers,but also introduced to China new scientific propositions,concepts,and numerical examples originating from the seminal Renaissance work Della misura dell’acque correnti(Of the Mensuration of Running Waters;1628)by Benedetto Castelli(1578–1643).In addition,Verbiest presented to his readers some noteworthy examples of pertinent Western achievements such as the pound-lock with miter gate,and he provided them with a simple economic analysis of flood control options.The significance and possible influence of Verbiest’s text on further developments in Chinese approaches to water engineering are discussed,highlighting a hitherto largely disregarded facet of Western science and technology transfer in the field of river hydraulics and flood management.
文摘For the assessment of the impact of future climate change on the hydrologic regime and water resources of Peninsular Malaysia, it is necessary to downscale the climate change simulations of a coarse scale General Circulation Model to the region of Peninsular Malaysia at fine grid resolution. This paper presents a desktop review of the state of climate change parameters, namely rainfall and river flow over the Peninsular Malaysia for the 2041-2050 projection period. Analysis of the results from the models shows there will be a substantial increase in mean monthly precipitation over the North East Coastal region from historical 259.5 mm to 281.5 mm, from 289.0 mm to 299.0 mm and 221.8 mm to 239.5 mm over Terengganu and Kelantan, respectively. Meanwhile, for river flow projection, it will be an expected increase in interannual and intraseasonal variability with increased hydrologic extremes （higher high flows, and lower low flows） at Kelantan, Pahang, Terengganu, and Kedah watersheds in the future.
基金supported by Guangxi Natural Science Foundation(Grant No.2012GXNSFEA053001)the project entitled "The Beibu Gulf forecast circulation system construction and Its Application to the Coastal Pollution Transport"
文摘Due to limited in situ data and diagnostic numerical models, the summer circulation structure and formation mechanism in the Beibu Gulf have always been in controversy in the past 50 years. Therefore, a new three-dimensional hindcast model was built within the northwestern South China Sea(SCS), forced with the daily averaged wind, heat flux, lateral flux, as well as tidal harmonic and eight major rivers discharges. And the east boundary was set up far away off the Qiongzhou Strait(QS). Lastly, the model results were consistent with not only the synchronous observation data from the project 908 but also the historical observed data. As a result, the summer circulation structure was revealed that the southern Gulf was occupied by an anticyclonic eddy whereas the northern Gulf was dominated by a cyclonic gyre. Although the circulation major structure was stable, its area and strength had yearly and monthly oscillation. The other three sensitive experiments indicated that the circulations in the southern and northern Gulf were driven by the SCS circulation and monsoon wind, respectively. After the theoretical analysis of the potential vorticity budget, it was further revealed the circulation in the northern Gulf was driven by the positive wind stress curl in summer. Besides, the river discharge was also significant as the vertical circulation had two layer structures outside the mouth of the Red River. Generally, this work calls for the further research on other subjects, such as ocean biogeochemical or marine fisheries.
