1. Improvement of Solder Bonding Characteristics Using New Electroless Thin Ni/Au Plating Process

    Tomohito KATO1,3, Hajime TERASHIMA3, Hideto WATANABE3, Mitsuhiro WATANABE2, Hideo HONMA2, Osamu TAKAI1, 2

    1. Graduate School of Engineering, Kanto Gakuin University, 1-50-1, Mutuurahigashi, Kanazawa-ku, Yokohama-shi, Kanagawa, 236-0004, Japan.
    2. Material Surface Engineering Research Center, Kanto Gakuin University, Yokohama Kanazawa High-Tech Center, 1-1-1, Fukuura, Kanazawa-Ku, Yokohama-shi, Kanagawa, 236-0004, Japan.
    3. Kojima Chemicals Co., LTD., 337-26, Kashiwabara, Sayama-shi, Saitama, 350-1335, Japan.

    Abstract: Fine pattern formation (Line Width/Line Space is less than 50µm) using electroless Ni/Au plating, extraneous Ni deposition on the resin area of fine pattern often observed due to the residual Pd catalyst on the patterns. Thinner Ni plating was applied to solve the problem. However, the tendency for local Ni corrosion by the immersion Au plating step increases, and solder connection reliability decreases compared to conventional Ni/Au process. Accordingly, the influence of Pd catalyst deposition conditions on electroless Ni/Au plated film properties was investigated. We propose the direct electroless Ni strike plating on the Cu patterns without the Pd catalyst. Generally, solder bonding strength with the electroless thin Ni/Au plating decreased with increase in Pd catalyst treatment time. On the contrary, solder bonding strength does not influence by the Ni strike plating time. Uniform Ni deposition and good solder bonding strength was accomplished by the application of the electroless Ni strike plating method.

    Keywords: Thin electroless Ni/Au plating process, Electroless Ni strike plating, Uniformity of Ni plating film, Intermetallic, Solder ball shear strength.

    Pages: 359 – 377 | Full PDF Paper
  2. The Concentration of Trace Metals and Hydrocarbons Depending on Water Column Depth in Caspian Sea Taken from Areas of Azerbaijan

    Majid M. Ahmadov and Navai A. Ibadov

    Institute of Radiation Problems of Azerbaijan NAS, 121 H.Javid aven, AZ1143, Baku, Azerbaijan.

    Abstract: The present study was conducted to investigate the heavy metal contents (As, Ba, Cu, Ga, Mo, Rb, U, and V) and hydrocarbons (Total Hydrocarbons (THC) and 16EPA Polycyclic Aromatic Hydrocarbons (PAHs)) in seawater samples, which were collected at two different sites of Azerbaijan sector of the Caspian Sea. The Agilent 7700x Series ICP-MS (inductively coupled plasma mass spectrometry) with HMI (high matrix introduction) system applied to analysis seawater. Depending on concentration of elements from water columns depth can be explained in accordance with the geochemical system of classification of dissolved forms of elements in the sea water. Hydrocarbons are extracted with methylene chloride, after the extracts are cleaned on silica-gel columns and then injected into GC/FID (GC7890B, Agilent) for determination of THC and GC/MS (TRACE/DSQ, Thermo-Electron-Finnigan) operating in the selected-ion-monitoring (SIM) mode for determination of the 16EPA PAHs. The average concentrations of total hydrocarbons were below the admissible environmental levels. THC ranged from 20-29 µg/L and PAHs from <10-29 ng/L, respectively.

    Keywords: ICP-MS,THC, 16EPA PAHs, GCFID, GC/MS SİM.

    Pages: 378 – 390 | Full PDF Paper
  3. Quality of Water Resources in Kufra Basin, SE Libya

    Mabrouk M. Salama1 and Saad K. El Ebaidi2

    1. Department of chemistry, University of Benghazi, Benghazi, Libya.
    2. Department of Earth Sciences, University of Benghazi, Benghazi, Libya.

    Abstract: Kufra basin has a maximum thickness of 900 m, where located in the south-eastern part of Cyrenaica in Libya and covers of about 400,000.00 km2. The sediments of the Kufra basin are mainly continental or marginally marine sandstones clays and shales, The large central part of the kufra basin was occupied by the Upper Cretaceous Nubian sandstone. The Nubian sandstone is one of the major sedimentary basins occur in eastern Libya. Information from water wells drilled in the Kufra basin indicates that Nubian sandstone consists mainly of unconsolidated sandstones interbedded with varying amounts of clays and shales. The main water resources studied in Kufra are derived from the ground water drilling wells are variable in depth where the total depths are ranging in meter from 140 m to 333 m. This paper focus on the parameters including pH values of 7.16 to 7.35, electrical conductivity (E.C) values of 104.8 to 1800 mg/l. The water quality is very fresh with dissolved solids (T.D.S) typically less than 162 mg/l, sodium (20.02 – 295 mg/l), potassium (4.48 – 23 mg/l), magnesium (9.15 –25.25 mg/l and calcium (15 –75 mg/l). The microbiological analysis showed that the ground water in Kufra is drinkable and free of any environmentally harmful pollutants. The available chemical analyses are in accordance with the Libyan and World Health Authority (WHO) would indicate an acceptable Drinking Water Standards.

    Pages: 391 – 398 | Full PDF Paper
  4. Comments on Some Transformation Methods of PV Solar Cells’ I-V Characteristics from their Implicit Forms to Explicit Ones

    Bashahu, M. and Ngendakuriyo, I.

    Department of Physics and Technology, Institute of Applied Pedagogy, University of Burundi, Bujumbura.

    Abstract: Most of the times, an implicit form of a PV solar cell’s I-V characteristic is used in the analysis of the electrical behavior of any circuit enclosing that electronic component. That analysis aims notably to determine the conductance at different points of the characteristic and then to extract component’s model parameters such as the reverse saturation current (Is), the ideality factor (n), the series and shunt resistances (Rs and Rsh, respectively). When numerical simulations are performed using the above mentioned form of the I-V characteristic, the process is quite slow. Explicit forms of that characteristic are in great demand, since simulations using them are about several tens fold faster than the implicit ones. References on explicit forms of PV solar cells’ I-V characteristics are rather scarce in the literature. The main objective of this work is an analysis of four selected techniques transforming those I-V characteristics from their implicit forms to explicit ones. Those techniques are namely: (i) the area’s, (ii) the generalized area’s, (iii) the trial function’s, and (iv) the Lambert W-function’s methods, respectively. The analysis is conducted notably in terms of the device operation conditions, kind of solar cell’s model and assumptions, related implicit form of the I-V characteristic, derived explicit form(s), outcomes’ expressions, method’s applications and further comments.

    Keywords: Area’s methods; Extraction of solar cells’ parameters; Generalized area’s method; Lambert W-function’s method; Trial function’s method.

    Pages: 399 – 408 | Full PDF Paper