Characteristics of sea ice kinematics from the marginal ice zone to the packed ice zone observed by buoys deployed during the 9th Chinese Arctic Expedition     

Xiaomin Chang  Longchun Ye  Guangyu Zuo  Jingyue Li  Keyu Wei  Yinke Dou 《海洋学报(英文版)》2022,41(7):113-127

Sea ice growth and consolidation play a significant role in heat and momentum exchange between the atmosphere and the ocean. However, few in situ observations of sea ice kinematics have been reported owing to difficulties of deployment of buoys in the marginal ice zone (MIZ). To investigate the characteristics of sea ice kinematics from MIZ to packed ice zone (PIZ), eight drifting buoys designed by Taiyuan University of Technology were deployed in the open water at the ice edge of the Canadian Basin. Sea ice near the buoy constantly increased as the buoy drifted, and the kinematics of the buoy changed as the buoy was frozen into the ice. This process can be determined using sea ice concentration, sea skin temperature, and drift speed of buoy together. Sea ice concentration data showed that buoys entered the PIZ in mid-October as the ice grew and consolidated around the buoys, with high amplitude, high frequency buoy motions almost ceasing. Our results confirmed that good correlation coefficient in monthly scale between buoy drift and the wind only happened in the ice zone. The correlation coefficient between buoys and wind was below 0.3 while the buoys were in open water. As buoys entered the ice zone, the buoy speed was normally distributed at wind speeds above 6 m/s. The buoy drifted mainly to the right of the wind within 45° at wind speeds above 8 m/s. During further consolidation of the ice in MIZ, the direct forcing on the ice through winds will be lessened. The correlation coefficient value increased to 0.9 in November, and gradually decreased to 0.7 in April.  相似文献   

乙醇干预ApoE^-/-小鼠离体心肌缺血再灌注模型的实验研究          下载免费PDF全文

林新文  陈娜  陈文明 《应用海洋学学报》2022,38(8):168

目的：研究高脂饲喂ApoE^-/-小鼠的动脉粥样硬化小鼠心肌缺血再灌注模型。方法：将28只ApoE^-/-小鼠按体质量随机分为2组：正常对照组（10只）、模型组（18只）。正常对照组常规饲养,模型组给予高脂饲料16周建立动脉粥样硬化模型。造模成功后,将模型组16只随机分为2组：模型对照组、乙醇损伤组,每组各8只。模型对照组继续进行高脂造模,乙醇损伤组在给予高脂饲料的同时日常饮用25%的乙醇10μl,正常对照组给予普通饲料饲养。连续4周。造模结束后,采用离体灌流装置（Langendorff）对各组心脏进行离体灌流,并对模型对照组小鼠离体心脏进行冠状动脉左前降支结扎,结扎30 min,复灌120 min。检测灌流复灌5 min和10 min时灌流液中乳酸脱氢酶（LDH）的含量,心肌组织中半胱氨酸蛋白酶-3(Caspase-3)和乙醛脱氢酶2(ALDH2)的含量。测定心肌梗死面积,并对心肌组织进行组织病理学检查。结果：模型组小鼠主动脉脂质斑块形成,血管壁可见内膜明显增厚,血管狭窄;缺血再灌注模型ApoE^-/-小鼠在结扎LAD前心电图ST段抬高,提示造模成功。小鼠心脏复灌5 min和10 min灌流液中LDH含量及心肌组织中Caspase-3、ALDH2含量,心肌梗死面积,心肌组织病理评分方面,模型对照组、乙醇损伤组与正常对照组比较,乙醇损伤组与模型对照组比较,差异均有统计学意义（P<005或P<001）。ApoE^-/-小鼠心肌组织TTC染色结果显示,与正常对照组比较,模型对照组心肌梗死部位明显增加,与模型对照组比较,乙醇损伤组心肌梗死面积明显减少。结论：乙醇诱导对ApoE^-/-动脉粥样硬化小鼠心肌缺血再灌注具有明显的保护作用,其机制与调节Caspase-3、ALDH2含量有关。  相似文献   

哈拉湖岩芯XRF扫描元素统计分析及其环境意义   总被引：3，自引：0，他引：3  

马雪洋  陈豆  阳亚平  张玉枝  张家武 《盐湖研究》2014,(4):1-10

青藏高原东北缘高山湖泊哈拉湖是位于季风与西风影响的交汇带的封闭深水湖泊,是区域环境和气候变化的良好记录载体。目前对该湖的研究还较少,缺乏对沉积物中元素环境意义的系统认识。通过高分辨率XRF岩芯扫描,用相关、聚类和因子分析的方法对哈拉湖沉积岩芯地球化学元素进行分析。结果显示Ti、K、Si、Al、Fe、Mn等元素变化一致,相关性高,归为同一类,即径流输入的陆源碎屑组分,反映了流域水文状况如径流量的变化。Sr、Zr元素相关性高,为赋存在粗颗粒沉积物中的元素,根据哈拉湖实际,应为冬季湖泊冰面风力搬运,反映了湖区冬季风力强度的变化。Ca元素既与径流输入元素总体变化一致,也与Sr、Zr元素显著相关,且在第一和第二主成分(径流和风力)上的载荷相当,表明哈拉湖沉积物中的碳酸盐既有粗颗粒的外源碎屑,也有湖泊自生的组分,这在利用碳酸盐进行地球化学研究时应重视,注意去除外源碎屑碳酸盐的影响。可溶元素S和Cl可能反映了入湖水量与蒸发对比情况,与湖泊盐度有关。  相似文献   

Zinc and copper bioaccumulation in fish from Laizhou Bay,the Bohai Sea     

刘金虎  曹亮  黄伟  张传涛  窦硕增 《中国海洋湖沼学报》2014,32(3):491-502

Abstract Zinc （Zn） and copper （Cu） concentrations were determined in the tissues （muscle, stomach, liver, gills, skin, and gonads） of five commercial fish species （mullet Liza haematocheilus, flathead Platycephalus indicus, mackerel Scomberomorus niphonius, silver pomfret Pampus argenteus, and sea bass Lateolabrax japonicus） from Laizhou Bay in the Bohai Sea. Metal bioaccumulation was highest in the metabolically active tissues of the gonads and liver. Bioconcentration factors for Zn were higher in all tissues （gonads 44.35, stomach 7.73, gills 7.72, liver 5.61, skin 4.88, and muscle 1.63） than the corresponding values for Cu （gonads 3.50, stomach 3.00, gills 1.60, liver 5.43, skin 1.50, and muscle 0.93）. Mackerel tissues accumulated metal to higher concentrations than did other fish species, but bioaccumulation levels were not significantly correlated with the trophic levels of the fish. Zn and Cu concentrations in the tissues were generally negatively correlated with fish length, except for a few tissues of sea bass. Risk assessment based on national and international permissible limits and provisional tolerances for weekly intake of Zn and Cu revealed that the concentrations of these two metals in muscle were relatively low and would not pose hazards to human health.  相似文献   

湖南两次流域性致洪暴雨异同点分析     

许霖  姚蓉  陈斗 《气象研究与应用》2014,(2):27-31

利用常规气象资料、水情资料及灾情资料,对发生地点、季节及影响系统相似的2010年7月8-14日和2012年7月11-19日两次湖南省持续性大范围暴雨天气过程进行对比分析,结果表明：（1）两次暴雨过程均具有持续时间长、暴雨频繁且集中、累计雨量大、洪涝严重等特点;（2）东北冷涡加强、副高东退南落,冷、暖空气在湖南交汇,导致连续性暴雨发生;（3）“10.7”暴雨过程冷、暖气流势力相当,雨带呈东西向,稳定少动,致灾性强.而“12.7”暴雨过程冷空气势力较强,雨带呈移动性,虽然致灾范围广,但灾情较前者轻.  相似文献   

北京城区近地面比湿和风场时空分布特征   总被引：6，自引：1，他引：5       下载免费PDF全文

窦晶晶  王迎春  苗世光 《应用气象学报》2014,25(5):559-569

利用2008—2012年北京城区平均5 km的高密度自动气象站逐时观测数据,分析了北京城区近地面比湿、风向和风速的时空精细分布特征,初步探究了城市下垫面对局地气象要素的影响机制。研究表明:夏季白天北京城区为干岛,冬季城区表现为弱湿岛特征。受城市效应的影响,北京城区与郊区比湿日变化有明显差异。近地面10 m风受到地形、城市和季节性盛行风的共同影响。当气流经过城区时有明显的绕流现象。夏季05:00—10:00 (北京时,下同),受山风、弱的夏季偏南风和城市热岛共同作用,气流向城市中心辐合。冬季15:00—19:00,受季节盛行风偏北气流和谷风偏南气流的共同作用,在城区形成一条西北—东南走向的辐合线。对风速研究发现:城市粗糙下垫面使北京城区风速减小,二环路和三环路之间存在一条“n”状的风速小值带。由此可见,除已开展较多研究的城市热岛效应外,北京城市效应对近地面湿度和风场亦有显著影响。  相似文献   

黔西地区构造变形特征及其煤层气地质意义   总被引：1，自引：0，他引：1  

窦新钊  ;姜波  ;张文永  ;朱文伟  ;俞显忠  ;胡广青 《中国煤炭地质》2014,(8):54-59

黔西地区处于特提斯与滨太平洋两个构造域的交接地带,多期性质不同的构造作用形成了现今错综复杂的构造变形特征。根据构造变形的差异,可划分为织金-纳雍NE向构造变形区、水城-紫云NW向构造变形区和黔西南复杂构造变形区。在野外地质的基础上,结合微观变形特征和矿物流体包裹体测试分析,认为黔西地区构造变形属于上地壳低温-中低温环境下的脆性-脆韧性变形;由于黔西地区基底构造相对稳定,成煤期后断块内部变形较弱,煤储层形成了一定程度的构造裂隙,有助于渗透率的提高,煤层气勘探开发前景良好。  相似文献   

Estimates of potential nitrate reductase activity in sediments: comparisons of two incubation methods and four inhibitors     

Jian-gang Han  Long-shuai Dou  Yong-li Zhu  Ping-ping Li 《Environmental Earth Sciences》2014,71(1):419-425

Sediment samples, collected from a large shallow lake, Taihu, China, were incubated in two conditions (with and without air extraction) with regard to four soil enzyme’s inhibitors (dry and moist heat sterilizations, chloramphenicol and toluene) to estimate the potential nitrate reductase (Nar) activities. The objectives of paper were to define (1) whether to exclude air from the mixture of sediment and substrate solution prior to incubation was necessary, and (2) the efficacy of four inhibitors when assaying the enzyme. No significant difference between two incubation methods was found (P < 0.05), indicating that it is not necessary for estimating the potential Nar activity in the sediment to construct an initial anaerobic condition by air extractions prior to incubation. Toluene (1.0 mL/g sediment) and dry heat sterilization effectively and persistently inhibit the reduction of nitrate to nitrite during the incubation of 42 h. The authors concluded that both should be used as preferred inhibitors. In contrast, chloramphenicol (30 μg/g sediment) and moist heat sterilization inhibitors restrained nitrate reduction for <24 h only. In addition, it was found that no nitrite produced was substantially reduced in 24 h. Therefore, it should be needless for potential Nar activity estimation in the sediment to add 2,4-dinitrophenol to inhibit nitrite reductase.  相似文献   

Hydrothermal Dolomite in the Upper Sinian (Upper Proterozoic) Dengying Formation,East Sichuan Basin,China     

LIU Shugen  HUANG Wenming  JANSA Luba F.  WANG Guozhi  SONG Guangyong  ZHANG Changjun  SUN Wei  MA Wenxin 《《地质学报》英文版》2014,88(5):1466-1487

Hydrothermal Dolomite （HTD） is present in the Upper Sinian （Upper Proterozoic） Dengying Formation, east Sichuan Basin, China. The strata are comprised by primary dolomite. The HTD has various textures, including zebra dolomite, subhorizontal sheet-like cavities filled by saddle dolomite and breccias cemented by saddle dolomites as well occur as a fill of veins and fractures. Also co-occur MVT type lead-zinc ores in the study area. The δ13C and δ18O isotopes of HTD in the Upper Sinian Dengying Formation are lighter than those of the host rocks, while STSr/86Sr is higher. The apparent difference in carbon, oxygen and strontium isotopes, especially the large difference in S7Sr/S6Sr isotopes ratio indicate crystallization from hot basinal and/or hydrothermal fluids. Saddle dolomite was precipitated at temperatures of 270-320℃. The diagenetic parasequences of mineral assemblage deposited in the Dengying Formation are： （1） dolomite host rock →sphalerite-galena-barite-fluorite; （2） dolomite host rock →saddle dolomite →quartz; （3） dolomite host rock →saddle dolomite→bitumen; （4） dolomite host rock →saddle dolomite →barite. The mean chemical composition of the host dolomite matrix and HTD didn＇t change much during hydrothermal process. The fluids forming the HTDs in the Dengying Formation were mixtures of freshwater from the unconformity at the top of Sinian, fluids from diagenetic compaction and hydrocarbon generation ＆ expulsion from the Lower Cambrian Niutitang Formation mudstones or the Doushantuo Formation silty mudstones, and hydrothermal fluids from the basement. The hydrocarbon reservoirs associated with the HTD were mostly controlled by the basement faults and fractures and karsting processes at the unconformity separating Sinian and Cambrian strata. The hydrocarbon storage spaces of HTD included dissolved cavities and intercrystalline pores. Dissolution cavities are extensive at the top of Dengying Formation, up to about 46m below the unconformity between Sinian an  相似文献   

基于乡村多功能理论的少数民族传统聚落景观风貌演化特征及影响机制研究——以湖南怀化皇都村为例     

李伯华  周璐  窦银娣  刘沛林 《地理科学》2022,42(8):1433-1445

在快速推进城镇化的背景下,以湖南省怀化市皇都村为例,基于乡村多功能理论,探究乡村聚落景观风貌演化过程和驱动机制。采用参与式农村评估方法,以Google Earth高清影像数据为基础,通过影像纠正拼接,结合实地调研数据,探究景观风貌的演变特征。研究显示：① 乡村多功能变化与聚落景观风貌变化是相互联系的,具有紧密的相关性;② 皇都村景观风貌演化阶段可分为缓慢且稳定的乡村传统功能型、无组织有方向的乡村生产功能型、矛盾到趋于协同的乡村现代功能型;③ 聚落的生活居住功能、生产保障功能、生态保育功能、商业服务功能、文化传承功能等多功能发展特征明显,多功能协调发展对景观风貌保护和演化具有积极意义;④ 皇都村景观风貌演变是一个动态的持续的过程,是内生驱动力、外源驱动力以及自然驱动力共同作用的外在表现,皇都村从单一的农业生产功能逐步向多功能路径转变,实现了景观风貌的多样性。  相似文献