期刊文献+
共找到365篇文章
< 1 2 19 >
每页显示 20 50 100
关于美国WaterSence~水箱式坐便器拍盖替换测试的研究
1
作者 商蓓 王远 《陶瓷》 CAS 2012年第21期19-20,共2页
对《WaterSense水箱式坐便器要求》新标准做了简单的介绍,并有针对性地对出口北美市场的WaterSence水箱式坐便器认证产品中较容易出现不符合项的排水阀拍盖替换试验进行了研究和分析。
关键词 watersence HET 拍盖替换
下载PDF
Effects of Biostimulation-Bioaugmentation on Coastal Microbial Community in an in situ Mesocosm System
2
作者 YUAN Fangzheng ZHAO Yangyong +2 位作者 DAI Yulai YANG Wen ZHU Jinyong 《Journal of Ocean University of China》 CAS CSCD 2024年第1期233-246,共14页
Globally,various types of pollution affect coastal waters as a result of human activities.Bioaugmentation and biostimulation are effective methods for treating water pollution.However,few studies have explored the res... Globally,various types of pollution affect coastal waters as a result of human activities.Bioaugmentation and biostimulation are effective methods for treating water pollution.However,few studies have explored the response of coastal prokaryotic and eukaryotic communities to bioaugmentation and biostimulation.Here,a 28-day outdoor mesocosm experiment with two treatments(bioaugmentation-A and combined treatment of bioaugmentation and biostimulation-AS)and a control(untreated-C)were carried out.The experiment was conducted in Meishan Bay to explore the composition,dynamics,and co-occurrence patterns of prokaryotic and eukaryotic communities in response to the A and AS using 16S rRNA and 18S rRNA gene amplicon sequencing.After treatment,Gammaproteobacteria and Epsilonproteobacteria were significantly increased in group AS compared to group C,while Flavobacteriia and Saprospirae were significantly reduced.Dinoflagellata was significantly reduced in AS compared to C,while Chrysophyta was significantly reduced in both AS and A.Compared to C,the principal response curve analyses of the prokaryotic and eukaryotic communities both showed an increasing trend followed by a decreasing trend for AS.Furthermore,the trends of prokaryotic and eukaryotic communities in group A were similar to those in group AS compared with group C,but AS changed them more than A did.According to the species weight table on principal response curves,a significant increase was observed in beneficial bacteria in prokaryotic communities,such as Rhodobacterales and Oceanospirillales,along with a decrease in autotrophs in eukaryotic communities,such as Chrysophyta and Diatom.Topological properties of network analysis reveal that A and AS complicate the interactions between the prokaryotic and eukaryotic communities.Overall,these findings expand our understanding of the response pattern of the bioaugmentation and biostimulation on coastal prokaryotic and eukaryotic communities. 展开更多
关键词 prokaryotic community eukaryotic community BIOAUGMENTATION BIOSTIMULATION coastal waters
下载PDF
A CFD Model to Evaluate Near-Surface Oil Spill from a Broken Loading Pipe in Shallow Coastal Waters
3
作者 Portia Felix Lee Leon +2 位作者 Derek Gay Stefano Salon Hazi Azamathulla 《Fluid Dynamics & Materials Processing》 EI 2024年第1期59-77,共19页
Oil spills continue to generate various issues and concerns regarding their effect and behavior in the marine environment,owing to the related potential for detrimental environmental,economic and social implications.I... Oil spills continue to generate various issues and concerns regarding their effect and behavior in the marine environment,owing to the related potential for detrimental environmental,economic and social implications.It is essential to have a solid understanding of the ways in which oil interacts with the water and the coastal ecosystems that are located nearby.This study proposes a simplified model for predicting the plume-like transport behavior of heavy Bunker C fuel oil discharging downward from an acutely-angled broken pipeline located on the water surface.The results show that the spill overall profile is articulated in three major flow areas.The first,is the source field,i.e.,a region near the origin of the initial jet,followed by the intermediate or transport field,namely,the region where the jet oil flow transitions into an underwater oil plume flow and starts to move horizontally,and finally,the far-field,where the oil re-surface and spreads onto the shore at a significant distance from the spill site.The behavior of the oil in the intermediate field is investigated using a simplified injection-type oil spill model capable of mimicking the undersea trapping and lateral migration of an oil plume originating from a negatively buoyant jet spill.A rectangular domain with proper boundary conditions is used to implement the model.The Projection approach is used to discretize a modified version of the Navier-Stokes equations in two dimensions.A benchmark fluid flow issue is used to verify the model and the results indicate a reasonable relationship between specific gravity and depth as well as agreement with the aerial data and a vertical temperature profile plot. 展开更多
关键词 CFD model Navier-Stokes equations projection method water surface oil spill shallow coastal waters
下载PDF
Retrieval of Antarctic sea ice freeboard and thickness from HY-2B satellite altimeter data
4
作者 Yizhuo Chen Xiaoping Pang +3 位作者 Qing Ji Zhongnan Yan Zeyu Liang Chenlei Zhang 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第3期87-101,共15页
Antarctic sea ice is an important part of the Earth’s atmospheric system,and satellite remote sensing is an important technology for observing Antarctic sea ice.Whether Chinese Haiyang-2B(HY-2B)satellite altimeter da... Antarctic sea ice is an important part of the Earth’s atmospheric system,and satellite remote sensing is an important technology for observing Antarctic sea ice.Whether Chinese Haiyang-2B(HY-2B)satellite altimeter data could be used to estimate sea ice freeboard and provide alternative Antarctic sea ice thickness information with a high precision and long time series,as other radar altimetry satellites can,needs further investigation.This paper proposed an algorithm to discriminate leads and then retrieve sea ice freeboard and thickness from HY-2B radar altimeter data.We first collected the Moderate-resolution Imaging Spectroradiometer ice surface temperature(IST)product from the National Aeronautics and Space Administration to extract leads from the Antarctic waters and verified their accuracy through Sentinel-1 Synthetic Aperture Radar images.Second,a surface classification decision tree was generated for HY-2B satellite altimeter measurements of the Antarctic waters to extract leads and calculate local sea surface heights.We then estimated the Antarctic sea ice freeboard and thickness based on local sea surface heights and the static equilibrium equation.Finally,the retrieved HY-2B Antarctic sea ice thickness was compared with the CryoSat-2 sea ice thickness and the Antarctic Sea Ice Processes and Climate(ASPeCt)ship-based observed sea ice thickness.The results indicate that our classification decision tree constructed for HY-2B satellite altimeter measurements was reasonable,and the root mean square error of the obtained sea ice thickness compared to the ship measurements was 0.62 m.The proposed sea ice thickness algorithm for the HY-2B radar satellite fills a gap in this application domain for the HY-series satellites and can be a complement to existing Antarctic sea ice thickness products;this algorithm could provide long-time-series and large-scale sea ice thickness data that contribute to research on global climate change. 展开更多
关键词 HY-2B satellite altimeter classification decision tree sea ice freeboard and thickness Antarctic waters
下载PDF
比利时杜鹃花花青素合成酶基因(RhANS)克隆及其功能分析 被引量:2
5
作者 蒋宝鑫 杨国霞 +3 位作者 吕思佳 贾永红 谢晓鸿 吴月燕 《核农学报》 CAS CSCD 北大核心 2023年第3期449-460,共12页
花青素合成酶(ANS)是植物花青素合成途径中的关键酶。为探究比利时杜鹃花(Rhododendron hybridum Hort.)ANS基因的功能及表达特性,本研究以比利时杜鹃花不同发育时期花瓣及盛花期的根、茎、叶为试验材料,利用反转录(RT-PCR)和RACE技术克... 花青素合成酶(ANS)是植物花青素合成途径中的关键酶。为探究比利时杜鹃花(Rhododendron hybridum Hort.)ANS基因的功能及表达特性,本研究以比利时杜鹃花不同发育时期花瓣及盛花期的根、茎、叶为试验材料,利用反转录(RT-PCR)和RACE技术克隆RhANS基因cDNA序列;利用超高效液相色谱质谱(Waters UPLC-Qtof)技术分析比利时杜鹃花不同发育阶段花瓣中花青素含量;利用实时荧光定量PCR(qRT-PCR)分析比利时杜鹃花不同发育阶段花瓣和不同器官中ANS基因相对表达量;将RhANS基因重组到原核表达载体(pET-28a)上,并在大肠杆菌(BL21)中进行表达纯化出目的蛋白,并利用高效液相色谱(HPLC)检测目的蛋白RhANS的酶活性。结果表明,从比利时杜鹃花克隆得到RhANS基因cDNA全长序列1350 bp,开放阅读框(ORF)序列1074 bp,编码357个氨基酸,含有2-酮戊二酸双加氧酶家族基因结构域2OG-FeⅡ-Oxy;比利时杜鹃花花青素含量随着花的开放呈逐渐上升的变化趋势;RhANS基因表达量在比利时杜鹃花4个花期的花瓣和不同器官(根、茎和叶)中均表达。不同花发育时期RhANS表达量与花青素含量呈上升趋势;通过大肠杆菌原核表达载体诱导表达出大小约为40 kDa的蛋白,与理论值相近。高效液相色谱仪(HPLC)检测表明,目的蛋白具有ANS酶活性。本研究为杜鹃花中花青素生物合成的分子调控机理提供了理论依据。 展开更多
关键词 比利时杜鹃花 花青素合成酶(ANS) 超高效液相色谱质谱(Waters UPLC-Qtof) 表达分析 原核表达
下载PDF
Genesis of Neogene Formation Waters in the Central Qaidam Basin:Clues from Hydrochemistry and Stable D-O-S-Sr Isotopes 被引量:1
6
作者 HAN Guang PAN Tong +4 位作者 LI Qingkuan FAN Qishun HU Yan LIU Jiubo ZHANG Xiying 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2023年第6期1801-1813,共13页
Geological explorations have revealed plentiful Neogene formation waters in anticlines in the central Qaidam Basin(QB).However,the hydrochemistry and origin of these waters are obscure.In this study,the hydrochemistry... Geological explorations have revealed plentiful Neogene formation waters in anticlines in the central Qaidam Basin(QB).However,the hydrochemistry and origin of these waters are obscure.In this study,the hydrochemistry and DO-S-Sr isotopes of these formation waters were determined to study their origin and evolution.The formation waters are enriched in Na-Ca-Cl,and depleted in Mg-K-SO4-HCO3ions with elevated Li-B-Br-Sr elements.The D-O isotopes prove that the formation waters originated from weak-evaporated meteoric waters,and experienced water-rock interactions.Ion comparisons and Caexcess-Nadeficitdiagrams suggest that solute sources of these waters include evaporite dissolution,waterrock interaction,and minor residual lake brines.Bacterial sulfate reduction and water-rock interactions are supported by the high S-Sr isotopes.The enriched Li-B-Br-Sr concentrations of these waters are in accord with the high geochemical background values of the QB.Regarding the genesis of the formation waters,it can be concluded that meteoric waters from the southern Kunlun Mountains were discharged into the basin,weakly evaporated,and then infiltrated into the Neogene strata through faults leaching the soluble ions and mixing with residual lake brines,and all experienced water-rock interactions and a sulphate reduction process. 展开更多
关键词 HYDROCHEMISTRY brine resources lake/meteoric waters D-O-S-Sr isotopes Miocene-Pliocene Qaidam Basin
下载PDF
DNA barcoding of fishes from Zhoushan coastal waters using mitochondrial COI and 12S rRNA genes 被引量:1
7
作者 Yehui WANG Na SONG +3 位作者 Shude LIU Zhi CHEN Anle XU Tianxiang GAO 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2023年第5期1997-2009,共13页
Accurate species identification is a key component of biodiversity research.DNA barcoding is an effective molecular method used for fish species identification.We aimed to study the DNA barcoding of fish in Zhoushan c... Accurate species identification is a key component of biodiversity research.DNA barcoding is an effective molecular method used for fish species identification.We aimed to study the DNA barcoding of fish in Zhoushan coastal waters,explore the differences and applicability of two gene fragments(12S rRNA and COI)of DNA barcoding in fish species identification,and established a comprehensive fish barcoding reference database.Two hundred and eighty-seven captured fish samples from Zhoushan coastal waters were identified using morphological characteristics and DNA barcoding.A total of 26412S rRNA sequences(belonging to eight orders,31 families,55 genera,and 66 species)and 188 COI sequences(belonging to seven orders,30 families,48 genera,and 58 species)were obtained.The lengths of the 12S rRNA sequences ranged from 165 to 178 bp,and the guanine-cytosine(GC)content was 45.37%.The average 12S rRNA interspecific and intraspecific genetic distances(K2P)were 0.10%and 26.66%,respectively.The length of the COI sequence ranged 574–655 bp,and the content of GC was 45.97%.The average 12S rRNA interspecific and intraspecific genetic distances(K2P)were 0.16%and 27.45%,respectively.The minimum interspecific genetic distances of 12S rRNA and COI(1.23%and 1.86%)were both greater than their maximum intraspecific genetic distances(2.42%and 8.66%).Three molecular analyses(NJ tree,ABGD,and GMYC)were performed to accurately identify and delineate species.Clustering errors occurred when the 12S rRNA sequences were delimited using the NJ tree method,and the delimitation results of ABGD and GMYC are consistent with the final species identification results.Our results demonstrate that DNA barcoding based on 12S rRNA and COI can be used as an effective tool for fish species identification,and 12S rRNA has good application prospects in the environmental DNA(eDNA)metabarcoding of marine fish. 展开更多
关键词 DNA barcoding cytochrome c oxidase subunit I(COI) 12S rRNA fish identification species delimitation Zhoushan coastal waters
下载PDF
Diagenesis of the Paleogene Sandstones in the DN2 Gas Field,Kuqa Foreland Basin and its Link to Tectonics
8
作者 YU Guoding YUAN Jing +4 位作者 LIU Keyu YANG Xianzhang DONG Daotao MA Pengjie HUANG Chiqiang 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2023年第5期1538-1554,共17页
We investigated diagenesis of the sandstones from the DN2 Gas Field of the Kuqa Foreland Basin(KFB),in order to infer the timing of fluid migration and discuss the linkage between fluids and tectonics.The textures and... We investigated diagenesis of the sandstones from the DN2 Gas Field of the Kuqa Foreland Basin(KFB),in order to infer the timing of fluid migration and discuss the linkage between fluids and tectonics.The textures and chemical composition of authigenic minerals,fluid evidence from fluid inclusions and formation water measurements were all used to fulfill this aim.Eodiagenesis occurred with the participation of meteoric water and connate water.Mesodiagenesis is related to high salinity fluids,which were attributed as originating from the overlying Neogene Jidike Formation evaporite(principal minerals including halite,anhydrite,glauberite,carnallite and thenardite).The onset of high salinity fluid migration is inferred to occur during the late Miocene(12.4-9.2 Ma)through the use of homogenization temperatures measured in the present study and K-Ar dating of authigenetic illites from previous work.This period is consistent with the crucial phase(13-10 Ma)that witnessed the rapid uplift of the southern Tianshan Mts and the stage when calcite and anhydrite veins formed in the studied strata.We thus argue that diagenesis related to high salinity fluids occurred as a response to the Tianshan Mts'rapid uplift and related tectonic processes.The flow of high salinity fluids was probably driven by a density gradient and channeled and focused by fractures formed contemporaneously. 展开更多
关键词 DIAGENESIS high salinity fluids meteoric waters TECTONICS Kuqa Foreland Basin Tianshan Mts
下载PDF
A comparison between high temperature catalytic and persulfate oxidation for the determination of total dissolved nitrogen in natural waters
9
作者 Tiantian Ge Xue Yang +1 位作者 Shan Jiang Liju Tan 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2023年第4期41-49,共9页
Total dissolved nitrogen(TDN) is an important parameter for assessing the nutrient cycling and status of natural waters.The accurate determination of TDN in natural waters is essential for assessing its contents and d... Total dissolved nitrogen(TDN) is an important parameter for assessing the nutrient cycling and status of natural waters.The accurate determination of TDN in natural waters is essential for assessing its contents and distinguishing different forms of nitrogen in the water.The TDN in various systems has been largely documented,and the concentrations of TDN are usually obtained using high-temperature catalytic(HTC) or persulfate oxidation(PO).However,the accuracy of these methods and their suitability for all types of natural waters are still unclear.To explore both methods in-depth,assorted samples were tested,including eight solutions composed of nitrogen-containing compounds(3 dissolved inorganic nitrogen fractions:NO_(3)^(-),NO_(2)^(-)and NH_(4)^(+);5 organic compounds:EDTA-2Na,vitamin B1,vitamin B12,amino acids,and urea) and 105 natural waters which were collected from an open ocean(Northwest Pacific Ocean,28),a marginal sea(Yellow Sea,34),an estuary(Huanghe River mouth,31),rivers(Huanghe River,4;Licun River,4),and precipitations(4 samples).The results showed that heterocycles and molecular dimensions had certain effects on the oxidation efficiency of the PO method but had little effect on HTC.There was no significant difference between the two methods for natural waters,but HTC was more suitable for deep-sea samples with low TDN concentrations(less than 10 μmol/L) and low organic activity.Overall,HTC has a relatively simple measurement process,a high degree of automation,and low error.Therefore,HTC can be recommended to determine the TDN of samples in freshwater and seawater. 展开更多
关键词 total dissolved nitrogen high-temperature catalytic persulfate oxidation natural waters
下载PDF
Contributions of annual and semiannual tidal constituents to chart datum in the China seas and adjacent waters
10
作者 Yikai Feng Yanguang Fu +1 位作者 Long Yang Dongxu Zhou 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2023年第10期127-136,共10页
Global uniform chart datum(CD)surface construction is the basic upon which to realize various vertical datums transformation,and is of great importance for geospatial data expression under the same vertical datum.Gene... Global uniform chart datum(CD)surface construction is the basic upon which to realize various vertical datums transformation,and is of great importance for geospatial data expression under the same vertical datum.Generally,the CD level is computed by developing the function between tidal constituents’harmonic constants and time,i.e.,the lowest astronomical tide is taken as the lowest predicted tide level by adopting the major constituents over a 19-a period.The CD surface prescribed in China is the theoretical lowest tide(TLT)and is calculated using 13 tidal constituents,i.e.,short-period(Q_(1),O_(1),P_(1),K_(1),N_(2),M_(2),S_(2),K_(2),M_(4),MS_(4)and M_(6))and long-period(Sa and Ssa)tidal constituents.Although the accuracy in determining short-period tidal constituents has improved gradually,the long-period tide has not been studied thoroughly owing to nonstationary and temporal variations.Previous studies have intended to evaluate the effect of Sa and Ssa tides in the determination of the TLT level for the purpose of determining a more accurate CD surface for the China seas and adjacent waters.Here,the parameters of long-period tidal correction and long-period tidal correction rate were treated as the effect of both Sa and Ssa on the TLT,and the TOPEX/Poseidon and Jason series satellite altimetry data ranged from October 1992 to April 2022 were adopted to analyze the contribution of long-period tidal constituents.Results showed that the average long-period correction value is 10.10 cm(range from 8.57 cm to 14.98 cm),and that the average long-period tidal contribution rate is 14.56%(range from 9.09%to 23.97%)in the China seas and adjacent waters.Finally,data from 82 tide gauge station with at least a 1-a record of hourly observations were compared with satellite-derived result.We concluded that the long-period tidal contribution should not be neglected in TLT construction.Furthermore,to reduce tidal datum uncertainty,accurate extraction of long-period tidal constituents should receive closer attentions. 展开更多
关键词 tidal datum chart datum long-period tidal constituent lowest normal low water China seas and adjacent waters
下载PDF
Production of Biogas from Olive Mill Waste Waters Treated by Cow Manure
11
作者 Fatma Laabidi Rafik Besbès Bassem Jamoussi 《Green and Sustainable Chemistry》 CAS 2023年第1期62-71,共10页
The olive mill waste waters (OMWW) generated from olive oil extraction is a major environmental concern since they are characterized by their role as a pollutant (high organic and mineral matters) and their pH acid. T... The olive mill waste waters (OMWW) generated from olive oil extraction is a major environmental concern since they are characterized by their role as a pollutant (high organic and mineral matters) and their pH acid. The aim of this study was to valorize (OMWW) by anaerobic fermentation in the presence of cow manure in order to produce biogas and reduce their toxic load. Many tests were carried out by fermenting (OMWW) with polyphenols in the presence of cow manure in thermophile temperatures. The performance of this treatment was valuated through measurements of biogas production and by the determination of different parameters of fermented media (pH, volume of the biogas and polyphenols). 展开更多
关键词 Olive Mill Waste Waters Anaerobic Fermentation Cow Manure BIOGAS POLYPHENOLS
下载PDF
Level of Bacteriological and Physicochemical Pollution of Surface Waters in Rural Area: The Case of Mbankomo Municipality (Center Region, Cameroon)
12
作者 Vanelle Lontchi Segnou Blandine Pulchérie Tamatcho Kweyang +6 位作者 Ernest Koji Siméon Tchakonte Murielle Patricia Mabou Tokam Olive Vivien Noah Ewoti Fils Mamert Onana Ornella Eunice Wandji Kweya Antoine Tamsa Arfao 《Journal of Geoscience and Environment Protection》 2023年第3期173-188,共16页
A study aimed at evaluating the physicochemical and bacteriological quality of surface water was therefore carried out in a few watercourses in the municipality of Mbankomo, located in the Center Region (Cameroon). Th... A study aimed at evaluating the physicochemical and bacteriological quality of surface water was therefore carried out in a few watercourses in the municipality of Mbankomo, located in the Center Region (Cameroon). The physico-chemical parameters were measured according to the standard method. The organic pollution index (OPI) was determined from the contents of nitrates, phosphates, and ammoniacal nitrogen to characterize the level of organic pollution of the water. The microorganisms sought were total flora, indicators of faecal contamination like total coliforms, faecal coliforms, feacal streptococci and Escherichia coli, as well as the species Clostridium perfringens. The organic pollution index indicates a high-level organic pollution level during the small rainy season and high to moderate during the small dry season. High concentrations of the total and fecal coliforms, streptococci fecal, Escherichia coli and Clostridium perfringens respectively of 1712 × 10<sup>5</sup> CFU/100mL;82 × 10<sup>5</sup> CFU/100mL;10 × 10<sup>5</sup> CFU/100mL;27 × 10<sup>5</sup> and 40 × 10<sup>3</sup> CFU/100mL, all higher than WHO standards, indicate that the waterways of Mbankomo are subject to feacal pollution and harbor pathogenic microflora. The cell densities of main bacteria were significantly correlated with main abiotic parameters, such as Escherichia coli, which was significantly correlated with the pH of the water (r = 0.35;p < 0.05). The variation of organic pollution index category means correspond to a high level of organic pollution during the small rainy season and a high to moderate level during the small dry season. The deterioration of the quality of these waters is favored by their proximity to sources of pollution (toilets, plantation), the runoff of the waters contaminated, the use of detergents and wrong maintenance. These waters without any treatment are not recommendable for human consumption according to standards of the World Health Organization. 展开更多
关键词 Bacteriological Quality Physicochemical Parameters Surface Waters Organic Pollution Index
下载PDF
Hydrodynamic Performance of a Newly-Designed Pelagic and Demersal Trawls Using Physical Modeling and Analytical Methods for Cameroonian Industrial Fisheries
13
作者 Tcham Leopold Vanlie Maurice Kontchou +2 位作者 Nyatchouba Nsangue Bruno Thierry Abdou Njifenjou Njomoue Pandong Achille 《Open Journal of Marine Science》 2023年第3期41-65,共25页
This study proposed the newly-designed Pelagic and demersal trawls for the fishing vessels operating in Cameroonian waters in pelagic and demersal fishing grounds. The engineering performances of both trawls were inve... This study proposed the newly-designed Pelagic and demersal trawls for the fishing vessels operating in Cameroonian waters in pelagic and demersal fishing grounds. The engineering performances of both trawls were investigated using physical modelling method and analytical method based on the predicted equations. In a flume tank, a series of physical model tests based on Tauti’s law were performed to investigate the hydrodynamic and geometrical performances of both trawls and to assess the applicability of the analytical methods based on predicted equations. The results showed that in model scale, the working towing speed and door spread for the pelagic trawl were 3.5 knots and 1.85 m, respectively, and for the bottom trawl net they were 4.0 knots and 1.8 m. At that speed and door spread, the drag force, net opening height, and wing-end spread of the pelagic model trawl were 36.73 N, 0.89 m, and 0.86 m, respectively, and the swept area was 0.76 m<sup>2</sup>. Bottom trawl speed and door spread were 30.43 N, 0.38 m, and 0.45 m, respectively, and the swept area was 0.25 m<sup>2</sup>. The maximum difference between the experimental and analytical results of hydrodynamic performances was less than 56.22% and 41.45%, respectively, for pelagic and bottom trawls, the results of the geometrical performances obtained using predicted equations were close to the experimental results in the flume tank with a maximum relative error less than 12.85%. The newly developed pelagic and bottom trawls had advanced engineering performance for high catch efficiency and selectivity and could be used in commercial fishing operations in Cameroonian waters. 展开更多
关键词 Cameroonian Waters Pelagic Trawl Bottom Trawl Engineering Performances Physical Model Test Analytical Methods Formatting
下载PDF
Fishing Dynamic and Stock Status of Endeavour Shrimp(Metapenaeus ensis de Haan)in Bombana Waters,South-East Celebes
14
作者 Ali Suman Anna Fitriani +3 位作者 Ap’idatul Hasanah Karsono Wagiyo Muhammad Taufik Syahroma Husni Nasution 《Journal of Environmental Science and Engineering(A)》 2023年第1期44-52,共9页
The high market demand for endeavour shrimp(Metapenaeus ensis de Haan)has caused intensive fishing for this resource and tends to threaten their sustainability.Assessment of fishing dynamic and stock status of fisheri... The high market demand for endeavour shrimp(Metapenaeus ensis de Haan)has caused intensive fishing for this resource and tends to threaten their sustainability.Assessment of fishing dynamic and stock status of fisheries resource is the main point to formulate its proper sustainable management in the future.The purpose of this study was to determine the stock status of endeavour shrimp in the Bombana and its surrounding waters.The study was conducted from April to November 2021 using a survey method to analyze the length at first capture(L_(c)),length at first maturity(L_(m)),growth rate(K),maximum theoretical carapace length(Loo),and mortality rate such as total mortality rate(Z),fishing mortality rate(F)and natural mortality rate(M).The study results revealed that the endeavour shrimp growth pattern in Bombana was negative allometric and that the ratio of males and females was not balanced.The length at first capture(L_(c))was 29.83 mm(carapace length)and the length at first maturity(L_(m))was at a total carapace length of 31.67 mm.The growth rate(K)was 1.0 per year and maximum theoretical length(L_(∞))was 46.2 mm.The estimate total mortality rate(Z)was 2.52 per year,the fishing mortality rate(F)and natural mortality rate(M)were 0.91 per year and 1.61 per year respectively.The exploitation rate(E)was 0.36 per year,therefore the stock status is not categorized overfishing.In order to ensure the sustainability of the endeavour shrimp,then the effort must be increased by about 28%of the current effort. 展开更多
关键词 Endeavour shrimp fishing gear population dynamic stock status Bombana waters FMA(Fisheries Management Area)714
下载PDF
HPLC-MS/ESI测定人血清中丙戊酸浓度 被引量:8
15
作者 朱运贵 李海菊 +3 位作者 王峰 肖轶雯 张毕奎 李焕德 《药物分析杂志》 CAS CSCD 北大核心 2005年第7期817-819,共3页
目的:建立HPLC-MS/ESI测定人血清中丙戊酸浓度的方法,并用于临床血药浓度监测。方法:采用Waters XTerraTM MS C18色谱柱(150 mm×3.9 mm,5μm),以10 mmol·L-1醋酸铵水溶液-乙腈(60:40)为流动相,流速0.80 mL·min-1,柱温45... 目的:建立HPLC-MS/ESI测定人血清中丙戊酸浓度的方法,并用于临床血药浓度监测。方法:采用Waters XTerraTM MS C18色谱柱(150 mm×3.9 mm,5μm),以10 mmol·L-1醋酸铵水溶液-乙腈(60:40)为流动相,流速0.80 mL·min-1,柱温45℃,以双氯芬酸为内标。采用电喷雾电离源(ESI)负源,用各物质准分子离子峰的选择离子监测(SIR)进行定量分析,血清样品用乙腈直接沉淀后进样。结果:丙戊酸在7.25-188.10μg·mL-1浓度范围内线性关系良好(r=0.9997),最低检测浓度为0.50μg·mL-1(S/N≥3)。日内与日间RSD均小于10%(n=5),方法回收率在98.7%-105.1%之间。结论:该方法操作简单,结果准确,血药浓度监测时间很短,灵敏度高;适用于丙戊酸血药浓度监测及药代动力学研究。 展开更多
关键词 HPLC-MS 酸浓度 人血清 ESI 测定 血药浓度监测 药代动力学研究 Waters C18色谱柱 选择离子监测 电喷雾电离 双氯芬酸 定量分析 分子离子 血清样品 线性关系 浓度范围 检测浓度 丙戊酸 流动相 水溶液 醋酸铵 RSD 回收率
下载PDF
丹参酮的提取工艺研究 被引量:14
16
作者 于纯淼 于栋华 于国萍 《中国中医药科技》 CAS 2006年第3期194-194,共1页
关键词 丹参酮ⅡA 工艺研究 高效液相色谱仪 药材公司 提取 FISHER WATERS 去离子水 超声仪器 超声波清洗
下载PDF
An Optimal Algorithm for the Retrieval of Chlorophyll,Suspended Sediments and Gelbstoff of Case Ⅱ Waters in the Pearl River Estuary 被引量:3
17
作者 杨锦坤 陈楚群 《Marine Science Bulletin》 CAS 2009年第1期13-23,共11页
An optimal algorithm for the retrieval of chlorophyll, suspended sediments and gelbstoff of case Ⅱ waters in the Pearl River estuary was established with the optical parameters derived from the in-situ data obtained ... An optimal algorithm for the retrieval of chlorophyll, suspended sediments and gelbstoff of case Ⅱ waters in the Pearl River estuary was established with the optical parameters derived from the in-situ data obtained in Jan. 2003 in the same area. And then, the chlorophyll, suspended sediments and gelbstoff of the SeaWiFS pixels on Jan. 29, 2003 corresponding to the in-situ sites of Jan. 25 and 26, 2003 were synchronously retrieved, with average relative errors of 14.9%, 12.1% and 13.6% for chlorophyll, suspended sediments and gelbstoff, respectively. The research results indicated that the optimal retrieval algorithm established here was relatively fit for the retrieval of the chlorophyll, suspended sediments and gelbstoff of case Ⅱ waters in the Pearl River estuary, and had quite good retrieval accuracy. 展开更多
关键词 Case Waters Optimal Retrieval Ocean Color Constituent Forward Model Atmospheric Correction Pearl River Estuary
下载PDF
有界恢复模型下弹性泄露签名的新构造 被引量:2
18
作者 王志伟 张伟 《小型微型计算机系统》 CSCD 北大核心 2012年第2期380-382,共3页
弹性泄露密码学是当前密码学研究的热点.给出一个弹性泄露签名的定义,该定义是标准签名定义的一个扩展.构造一个有界恢复模型下的弹性泄露签名方案,并在标准模型下证明了它的安全性.本文的方案基于双线性配对的弹性泄露签名,结合了一次... 弹性泄露密码学是当前密码学研究的热点.给出一个弹性泄露签名的定义,该定义是标准签名定义的一个扩展.构造一个有界恢复模型下的弹性泄露签名方案,并在标准模型下证明了它的安全性.本文的方案基于双线性配对的弹性泄露签名,结合了一次签名和Waters签名的特,通过改进,长度可大大缩短,克服了一次签名签名长度过长的缺点,具有较好的实用价值. 展开更多
关键词 弹性泄露签名 有界恢复模型 标准模型 Waters签名 一次签名
下载PDF
国家标准GB150用于压力容器大型端盖法兰设计的计算误差分析 被引量:1
19
作者 谭忠文 张征明 何树延 《核动力工程》 EI CAS CSCD 北大核心 2008年第3期56-58,共3页
压力容器大型法兰设计,如采用国家标准GB150做强度计算,得到的应力值往往偏小。当容器的大型端盖采用封头与大法兰直接连接的结构方式时,用GB150得到的应力值的计算误差可能更大。这是由于GB150中所用的法兰计算方法所决定的。本文以清... 压力容器大型法兰设计,如采用国家标准GB150做强度计算,得到的应力值往往偏小。当容器的大型端盖采用封头与大法兰直接连接的结构方式时,用GB150得到的应力值的计算误差可能更大。这是由于GB150中所用的法兰计算方法所决定的。本文以清华大学5 MW低温核供热试验堆工程安全壳设计为例,说明采用GB150进行大法兰设计的局限性。 展开更多
关键词 压力容器 法兰 应力 规范法设计 分析法设计 Waters法
下载PDF
改良Waters腹膜外剖宫产术 被引量:3
20
作者 邱学华 杨梦庚 +3 位作者 曹光玉 张晓莉 黄飞 尹国武 《第四军医大学学报》 1995年第2期156-156,共1页
改良Waters腹膜外剖宫产术邱学华,杨梦庚,曹光玉,张晓莉,黄飞,尹国武(唐都医院妇产科西安710038)关键词腹膜外剖宫产;新生儿;产后出血中图号R714.2以往腹膜外剖宫产术常存在娩胎困难及手术时间较长等缺点.... 改良Waters腹膜外剖宫产术邱学华,杨梦庚,曹光玉,张晓莉,黄飞,尹国武(唐都医院妇产科西安710038)关键词腹膜外剖宫产;新生儿;产后出血中图号R714.2以往腹膜外剖宫产术常存在娩胎困难及手术时间较长等缺点.自1992年12月起,我们以Wat... 展开更多
关键词 剖腹产 腹膜外剖腹产 手术方式 Waters式
下载PDF
上一页 1 2 19 下一页 到第
使用帮助 返回顶部