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1.
Naveed Ur RAHMAN XIAN Benzhong FANG Linhao CHEN Sirui CHEN Peng Zaheen ULLAH WANG Pengyu 《《地质学报》英文版》2024,98(3):753-770
The Carnian Pluvial Episode (CPE) fingerprints global environmental perturbations and biological extinction on land and oceans and is potentially linked to the Wrangellia Large Igneous Province (LIP). However, the correlation between terrestrial environmental changes and Wrangellia volcanism in the Ordos Basin during the CPE remains poorly understood. Records of negative carbon isotopic excursions (NCIEs), mercury (Hg), Hg/TOC, and Hg enrichment factor (HgEF) from oil shales in a large-scale terrestrial Ordos Basin in the Eastern Tethys were correlated with marine and other terrestrial successions. The three significant NCIEs in the study section were consistently correlated with those in the CPE successions of Europe, the UK, and South and North China. The U-Pb geochronology indicates a Ladinian–Carnian age for the Chang 7 Member. A comprehensive overview of the geochronology, NCIE correlation, and previous bio- and chronostratigraphic frameworks shows that the Ladinian–Carnian boundary is located in the lower part of Chang 7 in the Yishicun section. HgEF may be a more reliable proxy for tracing volcanic eruptions than the Hg/TOC ratio because the accumulation rates of TOC content largely vary in terrestrial and marine successions. The records of Hg, Hg/TOC, HgEF, and NCIEs in the Ordos Basin aligned with Carnian successions worldwide and were marked by similar anomalies, indicating a global response to the Wrangellia LIP during the CPE. Anoxia, a warm-humid climate, enhancement of detrital input, and NCIEs are synchronous with the CPE interval in the Ordos Basin, which suggests that the CPE combined with the regional Qinling Orogeny should dominate the enhanced rate of terrigenous input and paleoenvironmental evolution in the Ordos Basin. 相似文献
2.
KHATOON Helena HARIS Haris RAHMAN Norazira Abdu ZAKARIA Mimi Nadzirah BEGUM Hasina MIAN Sohel 《中国海洋大学学报(英文版)》2018,(3)
Microalgae are cultured commercially as healthy food, cosmetic products, food preservatives, and a source of valuable compounds. However, the high cost of commercial culture medium is one of the challenges to microalgal production. Therefore, it is essential to find an alternative cost-effective culture medium. Aquaculture wastewater is considered as a highly potential candidate due to its high nutrient content and large quantity generated from the rapid growth of aquaculture sector. In this study, Tetraselmis chuii cultured in different media with or without wastewater was evaluated for its growth, proximate composition and carotenoid production. The results showed that significantly(P 0.05) higher growth(4.3 × 105 cells mL~(-1)) and protein(56.4% dry weight), lipid(44% dry weight) and carbohydrate(20% of dry weight) contents were found in T. chuii when they were cultured in the combination of both wastewater and Conway(wastewater + Conway) medium. However, carotenoid production of T. chuii was significantly increased(P 0.05) when it was cultured in wastewater only, followed by Conway + wastewater and Conway medium only. Therefore, the incorporation of wastewater with commercial medium Convey is recommended for a cost-effective microalgae culture, as well as for the enhancement of growth and nutritional content of microalgae. 相似文献
3.
A. MANNAN S. WAHEED A. RAHMAN S. AHMAD I.H. QURESHI 《Geostandards and Geoanalytical Research》1993,17(2):223-226
Proposed standard reference material, coastal marine sediment (IAEA-356) recently released under the IAEA Analytical Quality Control Services programme, has been analysed by instrumental neutron activation analysis technique. Up to 32 elements have been measured using the multi-element analysis approach. The precision of measurements varied from 1.3 to 12.5% with median value of 4.9%. The quality control of the data has been validated by analysing IAEA reference material of similar matrix which shows excellent agreement with IAEA values. 相似文献
4.
A study was conducted in four selected upazilas under four coastal districts through participatory rural appraisal (PRA),
household survey and monitoring, sampling, focal group discussions, personal interview, onfarm field visits, institutional
consultations, and secondary information. The investigation revealed that the valuable natural resources of the whole region
are at the verge of serious degradation. Various causes have been identified, which are responsible for degradation of both
resources and production environments. These causes include human population growth, coastal embankment, upstream withdrawal
of Ganges water, brackish water shrimp farming, salt production, use of agro-chemicals, industrial activities, commercial
activities, over-exploitation, etc. The study also showed that the degradation of natural resources is the reason behind the
squeezing of historically dominant livelihood opportunities of the coastal communities. The current scenarios of the coastal
ecosystem urge necessary steps to be taken for sustainable management of valuable resources and to create alternative livelihood
opportunities for the coastal communities. 相似文献
5.
水稻是孟加拉国、印度和缅甸最重要的粮食作物,研究中国超级杂交稻对孟印缅地区的水稻增产潜力,对于保障孟中印缅经济走廊的粮食安全与区域可持续发展具有重要的现实意义。在全面收集孟印缅地区气候、土壤、田间管理信息和农业统计数据的基础上,结合中国籼型杂交稻F优498和丰两优4号的品种信息和区试数据,通过EPIC模型模拟了1996-2005年雨季孟印缅3国在不同情景下的超级稻生产潜力,并分析了孟印缅地区主要胁迫因子对超级稻单产潜力的影响。研究表明：① 中国超级杂交稻在孟印缅地区2000年的灌溉和施肥水平下单产潜力为10.22 t/ha,在充分灌溉且合理施肥的水平下单产潜力为11.33 t/ha。② 孟印缅地区雨季稻的增产空间达22771万t,水稻增产潜力最大的地区是印度的恒河平原东部、印度半岛东南沿海与缅甸的伊洛瓦底三角洲。③ 印度德干高原东北部、西南部和印度大平原西北部需要进一步完善灌溉设备以满足高产水稻用水,缅甸的中南部平原地区和印度的东北地区则需要增施氮肥以满足高产水稻用肥。 相似文献
6.
Tian Shufeng Chen Ningsheng Rahman Mahfuzur Hu Guisheng Peng Taixin Zhang Yong Liu Mei 《Landslides》2022,19(3):647-657
Landslides - In 2019, the catastrophic Zhaiban slope debris flow (ZSDF) crushed an open road tunnel in Ganluo County, Sichuan Province, China, causing seven deaths and interrupting traffic flow for... 相似文献
7.
LOCAL SCOUR ESTIMATION AT BRIDGE SITE: MODIFICATION AND APPLICATION OF LACEY FORMULA 总被引：1，自引：0，他引：1
Md. Munsur RAHMAN iwfm.buet.ac.bd at present: Post Doctoral Research fellow Ujigawa Open Laboratory Disaster Prevention Research Institute Kyoto University Shimomisu Yoko-Oji Fushimi-Ku Kyoto - Japan M. Anisul HAQUE 《国际泥沙研究》2003,18(4)
In the recent years, it has been established that b/h or h/b (b = length of the structure in the lateral direction and h = approach flow depth) is the dominant factor for the estimation of local scour depth around abutments and piers. One of the major limitations of the Lacey formula is that it predicts only one value of the scour depth for a specific river because of the absence of important parameters b and h. Therefore, its application is quite uncertain for variable b and h. Considering its limitations and experimental facts of flow concentration and shear stress amplification close to above structures, the original Lacey formula is modified introducing the parameters b and h. The applicability of the original as well as modified Lacey formula is tested to the data collected from major rivers in Bangladesh. 相似文献
8.
On 10th Oct.and 3rd Nov.2018,two successive landslides occurred in the Jinsha River catchment at Baige Village,Tibet Autonomous Region,China.The landslides blocked the major river and formed the barrier lake,which finally caused the huge flood disaster loss.The hillslope at Baige landslide site has been still deforming after the 2018 slidings,which is likely to fail and block the Jinsha River again in the future.Therefore the investigation of 2018 flood disaster at the Baige landslide is of a great significance to provide a classic case for flood assessment and early warning for the future disaster.The detailed survey revealed that the outstanding inundations induced bank collapse disasters upstream the Baige landslide dams,and the field investigations and hydrological simulation suggested that the downstream of the Baige landslide were seriously flooded due to the two periods of the outburst floods.On these bases,the early warning process of potential outburst floods at the Baige landslide was advised,which contains four stages:Outburst Flood Simulating Stage,Outburst Flood Fore-casting Stage,Emergency Plan and Emergency Evacuation Stage.The study offers a con-ceptual model for the mitigation of landslides and flood disasters in the high-relief mountain-ous region in Tibet. 相似文献
9.
孟加拉国沿海地区因其地理位置和自然灾害较多而归属生态环境脆弱地区,大约有3500万人生活在这里,他们的饮用水安全受到威胁。盐水入侵、砷和铁等重金属对水源的污染是造成水资源短缺的主要原因。海平面上升和气候异常事件加剧了沿海地区特别是西南沿海地区饮用水安全危机。本文以孟加拉国Satkhira地区的沿海Tala upazilas为例开展研究,采用基于GIS的多尺度分析方法来确定未来淡水缺乏解决方案和水源的选择,为此进行了问答式现场调查,收集研究区详细资料,以找到合适的水危机解决方案。基于浅层和深层两个不同含水层的资料(它们是饮用水主要来源的含水层水质),对不同水源的潜力和服务区域、社区的社会经济状况、用水类型以及相应的水源和用水需求进行了评价。研究发现,由于这里的地下水受砷、铁、盐碱污染,地表水又因管理不当而不能充分利用,在研究区及其附近很难找到其他的安全水源。在某些情况下,地表水在风暴潮期间由于高盐水的闪蒸和咸水养殖业的渗漏而遭污染。考虑到各种限制条件并结合现场数据、路网、聚落点位置、需水量等地理空间和社会经济信息进行分析,发现了一些符合社区饮用水需求的潜在水源点的分布位置,并提出了一些预防饮用水水危机和地表水可持续利用的技术措施。 相似文献
10.
FABIEN DURAND FABRICE PAPA ATIQUR RAHMAN SUJIT KUMAR BALA 《Journal of Earth System Science》2011,120(5):859-872
This study investigates the impact of monthly Ganges–Brahmaputra river discharge variations on Bay of Bengal salinity and
temperature during the period 1992–1999. The Ganges–Brahmaputra river discharge is characterized by a well-defined seasonal
cycle with strong interannual variations. The highest/lowest yearly peak discharge occurs in summer 1998/summer 1992, with
1998 value amounting to twice that of 1992. This river discharge is then used to force an ocean general circulation model.
Our main result is that the impact of these rivers on the variability of Bay of Bengal sea surface salinity is strong in the
northern part, with excess run-off forcing fresh anomalies, and vice versa. Most of the years, the influence of the interannual variability of river discharge on the Bay salinity does not extend south
of ~10°N. This stands in contrast with the available observations and is probably linked to the relatively coarse resolution
of our model. However, the extreme discharge anomaly of 1998 is exported through the southern boundary of the Bay and penetrates
the south-eastern Arabian Sea a few months after the discharge peak. In response to the discharge anomalies, the model simulates
significant mixed-layer temperature anomalies in the northern Bay of Bengal. This has the potential to influence the climate
of the area. From our conclusions, it appears necessary to use a numerical model with higher resolution (both on the horizontal
and vertical) to quantitatively investigate the upper Bay of Bengal salinity structure. 相似文献