2 The tendency of development in electronic components is influenced by performance enhancement and the reliability of the soldering. However, a number of issues regarding the reliability of solder joint interconnection is focusing to the interfaces between molten solder and substrate surface. This is due to the microstructure formed due to reaction rate between solder-substrate interfaces. There are several factor that influenced the reliability of soldering. However, the researchers shown that the intermetalliccompound (IMC) layer formed between the solder and the substrate as the most important factor that influenced the solder joint reliability.
Formation of intermetalliccompound at the Cu wire-Al bond pad interface of micro-chip attracts the interest of researchers. It is believed that formation and growth of Cu-Al IMC after HTS affects the performance and reliability of micro-chip. Due to very thin IMC formed (~20nm), the characterization techniques used are usually expensive and limitedly available, e.g. Transmission Electron Microscope (TEM) with Selective Area Diffraction (SAD). High resolution TEM and selective area diffraction studies show that initial phase formation belong to Al 2 Cu at as-bonded Cu-
For bonding wire material, Au wire is the most preferred bonding wire material because of its properties which do not oxidize during the process and easily to deform which capable to form a good ball bond. Normally, Au wire is connected to Al bond pad metallization then produced a new phase which is known as intermetalliccompound (IMC). However, this bonding system can cause the bond degradation and failure because of the excessive formation of Au-Al IMC and voids (Xu et al., 2011). In order to prevent the failure, thus a Copper (Cu) wire has become a selected wire bond material instead of Au wire since it has many advantages over Au wire. For example, it has high electrical, mechanical and thermal properties and low in terms of cost over Au wire. Other than that, the formation of IMC and void growth is much lower which can prevent from the failure (Xu et al., 2011). For bond pad metallization material, the Al bond pad metallization is the most preferred and suitable in wire bonding industry for decades due to the inexpensive and easily wire bondable.
Hughes et al. (1971); Taylor & Doyle (1972) had proved the lattice parameter of NiAl is 0.2887 nm. A maximum in the lattice parameter occurs at the stoichiometry composition. According to Fraser et al. (1973), some studies had shown a lattice parameter maximum at slightly Al rich compositions, these observations were probably due to inadequate control over the chemistry of the alloy and inaccurate methods of determination of the composition. Furthermore, Dey G.K. (2003) has noted that variation in density as a function of composition has been examined in the case of NiAl and it has been observed that the density of NiAl increases linearly with composition with increasing Ni content. The NiAl composition dependence of lattice parameter such as density has been used to interpret the nature of lattice defects especially point defects exist in the intermetalliccompound. Georg & Ralf (2008) verified that density increases and lattice parameter decreases with the increasing Ni content has been noticed on the Ni rich side. On the other hand, the density decreases and the Al content lattice parameter are more rapid on the Al rich alloy side. The B2 structure is shown on Figure 2.2
Intermetallic compounds which are also known for its superior thermal properties and good mechanical properties can be a potential candidate as alternative automobile bodies’ material. Intermetallic compounds offered a compromise between ceramic and metallic properties when hardness and/or resistance to high temperature are important enough to sacrifice some toughness and ease of processing. Therefore, an intermetalliccompound is generally brittle with high melting point. By the way, intermetallics can also display desirable magnetic, superconducting, and chemical properties, due to their strong internal order and bonding (metallic and covalent/ionic). Nickel based alloy is one of the intermetallics which has low density and low cost, comparatively. The Ni-Al binary phase diagram contains five intermetallic compounds which are Al 3 Ni, Al 3 Ni 2 ,
properties, enable nickel to be as one of the materials used in structural and high temperature application for many years. Some of the examples of the nickel properties are listed as followed: hard, malleable, ductile, fairly ferromagnetic, fair conductor of heat and electricity which is not affected by air or atmospheric water, therefore constitute as a very good characteristic against corrosion . Aluminum on the other hand is very light, nonmagnetic, highly malleable and fairly ductile . Having discussed both characteristics of the aluminum and nickel, it shows that by merging these elements in a specific manner will give an opportunity to form intermetallic compounds which are having highly ordered crystal structure. By having such structure in the compound, it enhances the mechanical properties of the compound; increases the strength and hardness, be lighter, and having high melting point temperature . In addition, this intermetalliccompound possesses high resistance towards corrosion. In considerations of the above, the aim of the present work is to alternate automotive body material with intermetallic Nickel Aluminides (Ni 3 Al) through
In this bioassay, two pure compounds (Compound 1 & Compound 2) isolated from the ethyl acetate fraction of seeds of Swietenia mahagoni were showed positive results indicating that the compounds are more or less biologically active. Each of the test samples were showed different mortality rates at different concentrations.
One oleanane glycoside was successfully isolated from the seeds of Barringtonia asiatica. The structure of this compound was determined by one- and two- dimensional 1 H- and 13 C-NMR and also by direct comparison with standard compound. This compound showed the highest insecticidal activity against Crocidolomia pavonana. The result showed that B. asiatica seeds have the most active insecticidal compound with LC 50 value of 290 ppm that is potential for
Sistem ini memerlukan 2 buah input citra, yaitu citra host dan citra watermark. Selanjutnya dilakukan penentuan suatu area piksel pada citra host yang nantinya akan disisipi dengan watermark. Setelah itu dilakukan resizing terhadap citra watermark agar ukurannya menjadi sama dengan ukuran area yang telah dipilih sebelumnya. Kemudian dilakukan penghitungan suatu nilai untuk dipetakan ke dalam area piksel yang telah ditentukan. Penghitungan dilakukan dengan menggunakan fungsi dari metode One to One Compound Mapping dengan melibatkan beberapa variabel seperti nilai piksel citra watermark serta nilai piksel persekitaran dari koordinat piksel citra host yang bersesuaian. Kemudian dilakukan pemetaan sehingga menghasilkan citra ter-watermark.
Solvent partitioning followed by column chromatography of the MeOH extract of the seeds of Swietenia mahagoni afforded two limonoids, swietenolide (compound 1) and 2-hydroxy-3-O-tigloylswietenolide (compound 2), later one is new compound. The compounds were identified by spectroscopic means. The cytotoxic activity of these compounds was assessed by using the conventional brine shrimp lethality bioassay. While both compounds were found to have moderate cytotoxic activity, compound 2 displayed overall more potent activity than compound 1.
Relatively few studies have been carried out on the neighboring platinum-based ternary intermetallic systems 19−22 although some amount of gold’s novel relativistic enhancement of bonding would seem likely for Pt. Most studies have pertained mainly either to higher cation or Pt proportions or to products unrelated to those in the present study.
All of the examples above are simple sentences. Each of them is an independent clause. They have a subject or more than one subjects and one or two verbs but they are only one clause. On example “a”, the simple sentence consists of one subject and one verb. On example “b”, the simple sentence consists of one subject and two verbs “enjoy and look forward to” then it is called a compound verb. On example “c”, contains two subjects “my friend and I” and two verbs “play and go” but it has only one clause, it is called simple sentence with a compound subject and a compound verb.
The study of compound words makes longer words more accessible and helps bridge the gap between single and polysyllabic word study. Through learning how the meaning of each morpheme contributes to the meaning of the compound word, students can develop an important word-attack strategy, increase their word-building skills, build vocabulary, reinforce spelling skills, and develop reading fluency. In learning those kinds of English learning, teachers and readers should use media to modify the bored strategy of teaching English in the class.
The next stage was the separation process using chromatographic techniques with Vacuum Liquid Chromatograph, Gravity Column Chromatography (GCC), and Thin Layer Chromatography (TLC). Prior to the separation, the ethyl acetate fraction concentrated in advance using silica gel was impregnated intended that the compound in the fraction bound to the silica gel so that secondary metabolites can be eluted only with a suitable solvent in the separation process with GCC. Thin Layer Chromatography (TLC) function to determine the appropriate eluent to be used in the process of GCC, as well as to test the purity of the isolated compounds.