Standing wave of finite-amplitude in an circular basin with uneven bottom

The effect of the particle cover over the density interface between two layers of fluids and of the suspended solid particles in the upper turbulcnt layer on the turbulent entrainment has been studied experimentally. The entrainment distance D is a function of the time of power: D=kt, where =0.200-0.130p. For suspended particles in the upper layer and pure 2-layer fluid is equal to 0.200, but the value of k for the suspended particles is smaller than that for the pure 2-layer fluid. The non-dimensional entrainment velocity is E=KRiln, where n=1.50+0.93 p. It is shown that the particle cover over the interface changes the power of Ril in the entrainment and hinders the turbulent entrainment. The variation rule of E for the suspended particles is the same as that for the pure 2-layer fluid, but the K value of the former is smaller than that of the latter. The turbulent mixing mechanism has been discussed.

A New Species of the Genus Garra from Nujiang River Basin, Yunnan, China (Teleostei: Cyprinidae)

2003年4月,于怒江二级支流镇康县境内的大叉河中采获一批墨头鱼属(Garra)鱼类标本,经鉴定为一新种,命名为怒江墨头鱼(G.nujiangensis Chen and Yang,sp.nov.).该新种主要鉴别特征:围尾柄鳞12～14:侧线鳞48～50:在小个体中有一对微小的吻须;背鳍分支鳍条8～9;侧线上鳞5～6,侧线下鳞3～4;体高小于头长;臀鳍起点处的小于眼后至吻端的距离;腹鳍前长为体长的50.0%～53.7%;肛门前长为体长的58.9%～63.9%:体宽为体长的16.7%～19.6%:体高为体长的19.2%～22.6%.本研究证实,在缺须的墨头鱼属的一些物种中,如高体墨头鱼(G.alticorpora)和怒江墨头鱼(G.nujiangensis),其幼体中往往具有一对很小的吻须.

XDistribution and Length2weight Relationships of Glyptosternoid Fishes in the Drung River Basin , Yunnan

鱼类主要分布于青藏高原周边, 是一群适合于急流生活的　科鱼类。在独龙江流域7 个点共采 集271 号　　鱼类标本(隶属　属、　属和异齿　属) , 结合各采集点数据绘制大鳍异齿　、藏　和扁头　的分布 直方图, 结果显示, 藏　( E. labiatum) 在流速较快的独龙江下游各采集点的种群数量较上游高, 更适应急流生 境。同时研究了这3 种　　鱼类的体长与体重的关系, 参数b (W = aLb) 的范围在218201 和310131 之间, 均为异 速生长; 藏　的生长类型最接近等速生长。