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Mountainous snow is essential substance in the earth surface because it is important for inland fresh water provision, global and local climate regulation and water cycles. The research is to monitor mountainous snow cover, simulate snow melt runoff using snowmelt runoff model (SRM) and assimilate state from remote sensing data into snow melt runoff model in the Langtang catchment. The first topic is to monitor snow cover in the Langtang catchment using MODIS snow product. It gives an analysis of snow cover area change with time. Inter- and between- annual analysis methods are two different perspectives for snow cover time monitoring. Some interesting trends would be drawn in this section. The results showed a seasonal variation in snow cover with two peaks and one minimum in snow cover percentage trends. The maximum snow cover area is...
Electrohydrodynamic atomisation (EHDA) spraying is a promising materials deposition technique as it allows uniform and regular deposition, and offers a range of other advantages, such as low cost compared with other current techniques, easy set-up, high deposition rate, ambient temperature processing and the capability to generate specific surface topographies. This research is aimed at using EHDA spraying to produce hydroxyapatite (HA) deposition with desirable chemical, topographical and biological characteristics for bone implant. In principle, the EHDA process involves the flow of liquid/suspension from a needle under the influence of an electric field which results jetting and droplet formation. In this work, phase-pure nano-sized hydroxyapatite (nHA) was synthesised and taken up in ethanol to prepare a suitable suspension for ele...
In een wereld waarin de hoeveelheid digitale afbeeldingen alsmaar groeit is het belangrijk te kunnen zoeken op basis van beeldinhoud. Xirong Li liet zich inspireren door sociale media en onderzocht de waarde van beelden met social tags voor visueel zoeken. Hij ontwikkelde verschillende algoritmen die automatisch bepalen of de tag die mensen aan een foto toevoegen overeenkomt met wat daadwerkelijk op de afbeelding te zien is. De beelden met relevante tags worden gebruikt als invoer voor een intelligente zoekmachine die ook onbenoemde beelden op het internet, een smartphone, of een laptop kan terugvinden. Op basis van vrij te verkrijgen beelden en hun tags ontwikkelde Li een zoekmachine waarmee het mogelijk is complexe visuele vragen te stellen, zoals de zoekopdracht voor een afbeelding van amazones langs het strand.
In this thesis, metal electrodeposition on semiconductor substrates is investigated. We show that electrodeposition of metals on n-type Si and Ge is an excellent method to create Schottky barriers and that this method has a number of unique advantages over other (physical) deposition methods. These advantages can be used to improve the prospects of applications in the area of Spintronics and Plasmonics. Firstly, the excellent current-voltage and capacitance-voltage characteristics of electrodeposited Schottky barriers indicate that they have an ideality factor close to unity and that the reverse bias leakage is orders of magnitude smaller than in evaporated Schottky barriers. These characteristics can be used to make highly doped Schottky barriers in which all reverse bias current is due to tunnelling. For magnetic metals, these Schot...
We consider the following special case of a conjecture due to Caccetta and H\"aggkvist: Let $D$ be a digraph on $n$ vertices that all have in-degree and out-degree at least $n/3$. Then $D$ contains a directed cycle of length 2 or 3. We discuss several necessary conditions for possible counterexamples to this conjecture, in terms of cycle structure, diameter, maximum degree, clique number, toughness, and local structure. These conditions have not enabled us to prove or refute the conjecture, but they lead to proofs of special instances of the conjecture.
The concept of a line digraph is generalized to that of a directed path graph. The directed path graph !Pk(D) of a digraph D is obtained by representing the directed paths on k vertices of D by vertices. Two vertices are joined by an arc whenever the corresponding directed paths in D form a directed path on k + 1 vertices or form a directed cycle on k vertices in D. In this introductory paper several properties of !P3(D) are studied, in particular with respect to isomorphism and traversability. In our main results, we characterize all digraphs D with !P3(D) �= D, we show that !P3(D1) �= !P3(D2) \almost always" implies D1 �= D2, and we characterize all digraphs with Eulerian or Hamiltonian !P3-graphs.
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