渍涝洼地鱼塘中浮游动物的变化     

谷孝鸿 《湖泊科学》1992,4(1):71-78

1987-1989年对山东省禹城渍涝洼地新开鱼塘水体中浮游动物进行了调查。1987、1988、1989年成鱼养殖期间共检出浮游动物种类分别为29、34、52种,平均数量为11911、39366.1、77889.2个/L,平均生物量为5.145、5.7675、9.6285mg/L。1988、1989年,鱼塘水体中浮游动物的数量高峰在7月。新开鱼塘养鱼前,只检出5种。数量为600个/L,生物量为0.0585mg/L。养鱼后三年来,鱼塘水体中浮游动物种类、数量及生物量的逐年增加,表明了新开鱼塘富营养化的演变程度。鱼塘施肥前后,水体中原生动物与轮虫的数量均有明显变化,其中原生动物变化更为明显。  相似文献   

2023年1—3月全球火山活动简报     

李萌萌  翟颖  顾国辉  陈鸿钰 《中国地震》2023,39(2):448-452

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A Study of the Star-forming Dwarf Galaxy NGC 855 with Spitzer     

Sheng-Peng Li  Qiu-Sheng Gu  Ying-He Zhao  Jia-Sheng Huang  Xin-Lian Luo Department of Astronomy  Nanjing University  Nanjing  Harvard-Smithsonian Center for Astrophysics  Garden Street  Cambridge  MA 《中国天文和天体物理学报》2007,7(6):764-770

We present a study of the dwarf elliptical galaxy NGC 855 using the narrow-band Hα and Spitzer data. Both the Hα and Spitzer IRAC images confirm star-forming activity in the center of NGC 855. We obtained a star formation rate (SFR) of 0.022 and 0.025M◎yr-1,respectively,from the Spitzer IRAC 8.0μm and MIPS 24μm emission data. The HI observa-tion suggests that the star-forming activity might be triggered by a minor merger. We also find that there is a distinct IR emission region in 5.8 and 8.0μm bands,located at about 10 away from the nucleus of NGC 855. Given the strong 8.0μm but faint Hα emission,we expect that it is a heavily obscured star-forming region,which needs to be confirmed by further optical spectroscopic observations.  相似文献   

不同养殖类型池塘浮游生物群落结构的初步分析   总被引：4，自引：1，他引：3  

谷孝鸿 《湖泊科学》1994,6(3):276-282

1988年在山东省禹城县渍涝洼地中选择四口鱼塘以不同放养类型进行试验,4—10月测定其浮游生物数量、生物量的变化。根据浮游生物各主要大类(如原生动物、轮虫以及蓝藻、绿藻、硅藻、隐藻和裸藻等)的变化,分析不同养殖类型池塘浮游生物群落结构变化的稳定性和同步性,同时分析了环境因子特别是生物营养物质的变化对浮游生物的影响。结果指出,肥水性鱼类在养殖池塘中因搭配比例的差异而导致池塘中浮游生物变化。  相似文献   

南极长城站附近海区冰藻色素的初步分析          下载免费PDF全文

李宝华  黄凤鹏  张坤诚 《极地研究》1992,4(4):18-23

本文报道了 1 988年 6 - 1 2月 (结冰期 )南极长城站附近海区冰藻色素的分离、鉴定结果。探讨了该海区冰藻色素的种类组成 ,季节变化以及冰藻色素在海洋生态系中的作用。结果表明 ,该海区冰藻已分离出色素 1 5种 ,可鉴定的有 1 3种 ,分别为 :胡萝卜素 ,脱镁叶绿素 a,叶绿素 a、b、c,叶黄素 ,岩藻黄质 ,脱植基叶绿酸 a,紫黄质 ,脱镁叶绿素 c,叶绿酸 a,叶绿素 c的衍生物 ,di-adinoxanthin,二种色素未能鉴定。该海域冰藻色素具明显的季节变化。  相似文献   

Petrogenesis and shock metamorphism of the enriched lherzolitic shergottite Northwest Africa 7755          下载免费PDF全文

Shu‐Zhou Wang  Ai‐Cheng Zhang  Run‐Lian Pang  Jia‐Ni Chen  Li‐Xin Gu  Ru‐Cheng Wang 《Meteoritics & planetary science》2017,52(11):2437-2457

Northwest Africa (NWA) 7755 is a newly found enriched lherzolitic shergottite. Here, we report its detailed petrography and mineralogy. NWA 7755 contains both poikilitic and non‐poikilitic lithologies. Olivine has different compositional ranges in the poikilitic and non‐poikilitic lithologies, Fa_30–39 and Fa_37–40, respectively. Pyroxene in the non‐poikilitic lithology is systematically Fe‐richer than that in the poikilitic lithology. The chromite grains in non‐poikilitic lithology are highly Ti‐richer than those in the poikilitic lithology. The chemical variations of olivine, pyroxene, and chromite between the poikilitic and non‐poikilitic lithologies support a two‐stage formation model of lherzolitic shergottites. Besides planar fractures and strong mosaicism in olivine and pyroxene, shock‐induced melt veins and pockets are observed in NWA 7755. Olivine grains within and adjacent to melt veins and/or pockets have either transformed to ringwoodite, amorphous phase, or dissociated to bridgmanite plus magnesiowüstite. Merrillite in melt veins has completely transformed to tuite; however, apatite only has partially transformed to tuite, indicating a relatively sluggish transformation rate. The partial transformation from apatite to tuite resulted in fractional devolatilization of Cl and F in apatite. The fine‐grained mineral assemblage in melt veins consists mainly of bridgmanite, minor magnesiowüstite, Fe‐sulfide, Fe‐phosphide, and Ca‐phosphate minerals. The coexistence of bridgmanite and magnesiowüstite in these veins indicates a shock pressure of >~24 GPa and a temperature of 1800–2000 °C. Coesite and seifertite are probably present in NWA 7755. The presence of these high‐pressure minerals indicates that NWA 7755 has experienced a more intense shock metamorphism than other enriched lherzolitic shergottites.  相似文献   

An energy conversion system based on deep-sea pressure   总被引：1，自引：0，他引：1  

Feng Wang  Linyi Gu  Ying Chen   《Ocean Engineering》2008,35(1):53-62

A novel seawater pressure energy conversion system that utilizes seawater pressure to generate electricity has been studied in this paper. The energy conversion system utilizes the pressure difference between the pressurized seawater and the empty pressure container to drive hydraulic motor and the coaxially coupled generator to generate electric power. The output electric energy is recorded by the data logger throughout the process. In the current study, technical analysis is performed with the emphasis on conversion efficiency between seawater pressure energy and output electric energy. The analysis is conducted at various pressure differences through the throttle valve so as to obtain maximum conversion efficiency. Research shows that the optimum pressure difference through the throttle valve and the maximum conversion efficiency can be theoretically calculated when the properties of the conversion system are given. Simulation results have demonstrated the influence of pressure difference on conversion efficiency. The test apparatus has been designed, built and tested in 2004. It successfully generated electric energy of approximately 0.85 kW h at the depth of 2400 m with empty pressure container's holding capacity of 200 L in the voyage “DY105-16” in South China Sea on June 12, 2004. The actual conversion efficiency from seawater pressure energy to electric energy reaches as high as 63.8% which is attractive for underwater equipments. The success of the experiment has tested the feasibility of utilizing seawater pressure energy and brings a new power supply way for long-term in-situ underwater equipments.  相似文献   

Growth of new designated cities in China     

顾朝林  甄峰  邱友良  叶舜赞 《中国地理科学(英文版)》1999,9(2):97-106

１ＩＮＴＲＯＤＵＣＴＩＯＮＭａｎｙｗｅｓｔｅｒｎｓｃｈｏｌａｒｓｓｕｃｈａｓＣｈａｎｇＳｅｎｄｏｕ（１９６３）,ＣｈｅｎｇＴｉｅｊｕｎｅｔａｌ．（１９９４）,ａｎｄＳｋｉｎｎｅｒＧ．Ｗ．ｅｔａｌ（１９７７）ｐｕｔｔｈｅｉｒｒｅｓｅａｒｃｈｉｎｔｅｒｅ...  相似文献   

平稳序列密度函数随机窗宽核估计     

谷震离  李雪臣  黄秀花 《地球科学与环境学报》1999,21(1):75

在平稳序列｛ｘｎ｝∞ｎ＝１是强混合的情况下,讨论具有随机窗宽的密度核估计的强一致相合性,得到了一般核下最近邻估计具有强一致相合性的结果。  相似文献   

<江苏省矿产资源管理条例>的立法背景、主要特点及其重要意义     

顾安麒  吴志良 《江苏国土资源》2000,25(3)

简要介绍了江苏省矿产资源形势、开发现状和存在的主要地质环境问题.介绍了<江苏省矿产资源管理条例>的立法背景、主要内容和重要意义.提出在当前形势下,认真学习、贯彻实施<条例>,应抓好5个方面的工作.  相似文献