LiGaO_2衬底上ZnO外延膜的结构与光学特性

采用磁控溅射法在(001)、(100)及(010)LiGaO2衬底上制备了ZnO薄膜,通过X射线衍射(XRD)、原子力显微镜(AFM)、透过光谱以及光致发光谱(PL)对薄膜的结构、形貌及光学性质进行了表征。结果表明LiGaO2衬底不同晶面上制备的ZnO薄膜具有不同的择优取向,在(001)(、100)及(010)LiGaO2上分别获得了[0001][、1100]及[1120]取向的ZnO薄膜;不同取向的ZnO薄膜表面形貌差异较大;薄膜在可见光波段具有较高的透过率;在ZnO薄膜的光致发光谱中只观察到了位于378 nm的紫外发射峰,而深能级发射几乎观察不到,(1100)取向的薄膜紫外发射峰强度最大,半高宽也最小,薄膜光致发光性质的差异主要和晶粒尺寸有关。

Triel Bonds, pi-Hole-pi-Electrons Interactions in Complexes of Boron and Aluminium Trihalides and Trihydrides with Acetylene and Ethylene

MP2/aug-cc-pVTZ calculations were performed on complexes of aluminium and boron trihydrides and trihalides with acetylene and ethylene. These complexes are linked through triel bonds where the triel center (B or Al) is characterized by the Lewis acid properties through its -hole region while -electrons of C2H2 or C2H4 molecule play the role of the Lewis base. Some of these interactions possess characteristics of covalent bonds, i.e., the Al--electrons links as well as the interaction in the BH3-C2H2 complex. The triel--electrons interactions are classified sometimes as the 3c-2e bonds. In the case of boron trihydrides, these interactions are often the preliminary stages of the hydroboration reaction. The Quantum Theory of Atoms in Molecules as well as the Natural Bond Orbitals approach are applied here to characterize the -hole--electrons interactions.

Photorelease of Pyridyl Esters in Organometallic Ru(II) Arene Complexes

New Ru(II) arene complexes of formula [((6)-p-cym)Ru(N-N)(X)](2+) (where p-cym = para-cymene, N-N = 2,2'-bipyrimidine (bpm) or 2,2'-bipyridine (bpy) and X = m/p-COOMe-Py, 1-4) were synthesised and characterized, including the molecular structure of complexes [((6)-p-cym)Ru(bpy)(m-COOMe-Py)](2+) (3) and [((6)-p-cym)Ru(bpy)(p-COOMe-Py)](2+) (4) by single-crystal X-ray diffraction. Complexes 1-4 are stable in the dark in aqueous solution over 48 h and photolysis studies indicate that they can photodissociate the monodentate m/p-COOMe-Py ligands selectively with yields lower than 1%. DFT and TD-DFT calculations (B3LYP/LanL2DZ/6-31G**) performed on singlet and triplet states pinpoint a low-energy triplet state as the reactive state responsible for the selective dissociation of the monodentate pyridyl ligands.

A note on application of hills procedure for growth-curve analysis of Indian major carp, Labeo rohita (Ham.), during the gonodal development period at Shillong, Meghalaya

The present study deals with the length increment data of 15 adult Labeo rohita (Ham.) over a period of five months by the applicatin of finite difference method at an altitude of 1496 m above mean sea level at Shilllong, Meghalaya.

渤海湾不同站点四角蛤蜊软体部重金属含量及AhR 通道研究

渤海湾沿岸人口密集，工农、航运发达，渤海自身净化能力非常有限。因此，渤海湾 环境污染的压力越来越大，主要污染物包括重金属和持久性有机污染物的。四角蛤蜊广泛 分布于渤海湾海域，是一种重要的经济贝类，对污染物具有较强的富集能力。为了研究不 同站点渤海湾四角蛤蜊软体部重金属含量，选择大港油田、高沙岭码头、涧河村三个断面 进行研究，对不同站点四角蛤蜊软体部重金属含量进行了分析和讨论，最后对水生动物的 POPs 毒理调控通道进行了探索性研究，得到以下结果： 1. 通过比较渤海不同站点四角蛤蜊软体部重金属含量分布特征和方差分析，发现四 角蛤蜊软体部必需重金属元素含量较高，而非必需重金属元素含量较低，这是由于必需重 金属元素具有重要的生理功能作用。侧重比较A、B 两个断面各站位间四角蛤蜊软体部重 金属含量，发现虽然各站位间分布规律不明显，但各站位间差异显著。 2. 利用简单相关回归分析金属元素间及其与生物学性状间的关系，发现Mn 与Zn 之 间，Cu 与Zn 间均存在显著正相关，Se 与As、Cd 间存在显著正相关。另外，A 断面，BL 与Cd 含量显著负相关其回归方程为：Y（Cd）=－1395.97＋88.34（BL）；R=0.633；在B 断面，利用BW 和BH 分别与Cd 和As 显著负相关和显著正相关，其回归方程分别为：BW 和Cd 的回归方程为：Y（Cd）=－1968.80＋220.72（BW）；R=0.656。BH 和As 的回归方 程为：Y（As）=1496.86＋227.82（BH）；R=0.656。 3. 利用PLS（偏最小二乘分析）方法分析，发现五个生物学性状都与Co、As 呈正相 关，而与Cr、Pb、Se 呈负相关，而与必须重金属元素相关不明显。进一步分析表明表明 渤海湾海域中Co、As 含量低于四角蛤蜊正常生长发育的需要，而Cr、Pb、Se 的含量超过 四角蛤蜊正常生长发育所需的量。最后，通过PLS-DA 分析方法，发现C 站点样品能与A、 B 两个断面的站点区分开，而A、B 间未能区分开，反映了渤海湾三个断面的实际污染状 况。 4. 四角蛤蜊软体部重金属含量进行风险评价，首先，利用单因子污染指数法比较分析， 发现从1997 年-2008 年，渤海湾四角蛤蜊软体部Cd 的污染水平在不断降低，现在其含量 已低于《海洋生物质量标准》（第二类）标准。而Cr、As 有污染的趋势，需要引起重视。 然后，利用金属污染指数法进行比较研究，发现B 断面＞A 断面＞C 断面。最后，利用《人 体消费卫生标准》进行比较分析，发现Cd、Ni 存在轻度污染，因此需要加强其污染源的 控制。 5. 渤海湾污染物除了重金属外，还存在一些典型持久性有机污染物。为进一步揭示 二者间协同毒理机制，利用分子系统学方法，对芳香烃受体通道进行了探索性研究，发现 水生动物AhR通道基因在进化过程中发生了适应性进化，对进一步研究重金属和POPs对双 壳贝类的毒理机制具有参考价值。

Movement of deposited water on turbomachinery rotor blade surfaces

A theoretical approach for calculating the movement of liquid water following deposition onto a turbomachine rotor blade is described. Such a situation can occur during operation of an aero-engine in rain. The equation of motion of the deposited water is developed on an arbitrarily oriented plane triangular surface facet. By dividing the blade surface into a large number of facets and calculating the water trajectory over each one crossed in turn, the overall trajectory can be constructed. Apart from the centrifugal and Coriolis inertia effects, the forces acting on the water arise from the blade surface friction, and the aerodynamic shear and pressure gradient. Non- dimensionalisation of the equations of motion provides considerable insight and a detailed study of water flow on a flat rotating plate set at different stagger angles demonstrates the paramount importance of blade surface friction. The extreme cases of low and high blade friction are examined and it is concluded that the latter (which allows considerable mathematical generalisation) is the most likely in practice. It is also shown that the aerodynamic shear force, but not the pressure force, may influence the water motion. Calculations of water movement on a low-speed compressor blade and the fan blade of a high bypass ratio aero-engine suggest that in low rotational speed situations most of the deposited water is centrifuged rapidly to the blade tip region. Copyright © 2006 by ASME.

National report of the frame survey 2006 in the Ugandan part of Lake Victoria

Fisheries Frame surveys have been carried out on Lake Victoria biannually since 2000 to determine· the number of fishers, fish landing sites, facilities at the landing sites. Information on the composition fishing crafts, their mode of propulsion, fishing gears and the fish species they target is also collected. This information is used to guide development and management of the lake's fisheries. The results of the four surveys carried out since 2000 show that the number of landing sites has decreased by 24% from 597 in 2000 to 481 in 2006, mainly as result of reorganisation of landing sites into Beach Management Units (BMUs). The fish landing sites continue to have inadequate facilities to service the fisheries industry e.g. in the 2006 survey only 11.2% of landing sites had fish shades; <0.6% had cold rooms; 3.5% had electricity; and only 35.5% had toilet facilities. Similarly, only 11.4% of landing sites had portable water; 2.5% had jetties, 3.7% had 'fish stores; and 36% were accessible by all weather roads. There is need to improve facilities servicing fisheries at landing sites, with major emphasis on sanitary facilities, especially toilets and portable water. The BMUs should be sensitised to prioritise the construction and utilisation of public toilet facilities at their respective landing sites. The ultimate aim should be to have public toilets at all fish landing sites. The trend of the various indicators of fishing effort has continued upwards: The total number of fishers increased by 43.5% from 37,721 in 2004 to 54,148 in 2006 and the number of fishing crafts increased (43.9%) from 16,775 in 2004 to 24,148 in 2006 over the same period. The total number of gillnets increased by 28.6% from 458,597 in 2004 to 589,777 in 2006 and the number of long line hooks increased by 136% from 968,848 to 2,285,609. The number of fishing crafts using outboard engines also increased from 3,173 in 2004 to 5,047 in 2006 suggesting that more fishers were going far in search of fish. There is still a large number of illegal gears especially beach seines, which increased by 58.8% from 954 in 2004 to 1420 in 2006. Efforts to remove these very destructive gears should be stepped up. There was also larger increase in number of illegal gillnets <5 inch mesh size. These increased by 63% from 56,246 in 2004 to 91,740 in 2006 compared with 23.8% increase of gillnets ~5 inch mesh size. There were also large increases in the numbers of gillnets of 5 and 5% inch mesh size, which increased by 48% and 130% from 2004 to 2006 implying a trend towards use of smaller gillnet mesh sizes. The number of traps which are used in shallow vegetated areas, flood plains and river mouths to target tilapiines and riverine species decreased drastically from 5,361 traps in 2004 to only 499 traps in 2006, a decrease of 974%, a phenomenon attributed to the receding water levels which have left the shallow vegetated areas dry. A total of 17,475 fishing crafts, 72% of all fishing crafts, in the Ugandan part of the lake are still using paddles and the. number of parachute crafts is also still very high, (Le. 5,064) comprising a high proportion (21 %) of the total number of fishing. There is need to promote the use of large fishing crafts with sails or a combination of sail and outboard motor. The Mukene fishery in the Ugandan waters of Lake Victoria has remained underdeveloped with only 9% of all fishing crafts operating in this fishery. Also less than 2% of fishing crafts with sails or motor operate in this fishery which implies that it is limited to near shore waters. Effort should be made to develop this fishery as it appears to have high potential, especially in deep offshore waters which are hardly fished.

7种长蠹科昆虫的线粒体DNA ND4基因序列比较分析

长蠹科昆虫严重危害林木和仓贮物品。该文应用非损伤性DNA测序技术测定了来自不同国家的长蠹科害虫的线粒体DNAND4基因的部分序列。在获得的 2 0 4bp的序列中 ,7种昆虫的序列变异丰富 ,多数变异发生在密码子的第 3位点上。将实验结果与形态学特征比较分析 ,探讨 7个种的形态差异与基因序列的差异 ;结果表明 ,7种昆虫不仅在外形特征上存在差异 ,而且在ND4基因序列上的差异程度也很显著 ,平均为 2 1 94%。这为分类鉴定提供了充分的证据。

The Brushless Doubly-Fed Machine vector model in the rotor flux oriented reference frame

The paper presents the vector model of the Brushless Doubly-Fed Machine (BDFM) in the rotor flux oriented reference frame. The rotor flux oriented reference frame is well known in the standard AC machines analysis and control. Similar benefits can be sought by employing this method for the BDFM The vector model is implemented in MATLAB/SIVIULINK to simulate the BDFM dynamic performance under different operating conditions. The predictions from the vector model are compared to those from the coupled circuit model in simulation. The results are shown for the cascade mode of operation. © 2008 IEEE.