Dalam penelitian ini akan ditinjau adalah pemodelan Nreca maupun Tanki pada Bendung Keru di DAS Babak yang memiliki ketersedian catatan debit air. Pemodelan dimulai dari kalibrasi model rain run ...sehingga mendapatkan koefisien Nreca dan Tanki pada AWLR Keru. Kemudian perhitungan debit pada Bendung Keru menggunakan data spasial serta data curah hujan dari ARR Keru. Hasil antara pemodelan pada Nreca dan Tanki dibandingkan dengan catatan debit pada Bendung Keru. Hasil dari penelitian ini adalah nilai koefisien model pada AWLR Keru di DAS Babak WS Lombok: a) Koefisien model NRECA yaitu untuk Tampungan kelengasan awal : 727; Tampungan kelengasan akhir: 312; Koefisien Reduksi: 0.27; Koefisien PSUB: 0.43; Koefisien GWF: 0.1; Beda tampungan awal dan akhir: 12; Nilai Korelasi: 0.84; Nilai Volume Error (VE): 0.33; b) koefisien model tanki yaitu Koefisien Tanki 1: Tank Awal : 868; H 1.1 : 29; H 1.2 : 28; F 1.1 : 794; F 1.2 : 661; B1: 254; Koefisien tanki 2: Tank Awal : 330; B2 : 585; Nilai Korelasi : 0.75; Nilai Volume Error (VE): 0.31. Dalam pemodelan debit untuk perhitungan ketersediaan air yang optimal di DAS Babak WS Lombok terutama pada Bendung Keru menggunakan model Tanki.
Unjuk kerja dari reaktor trickle bed tidak hanya dipengaruhioleh kinetika reaksi, melainkan juga oleh faktor perpindahan massa dan hidroninamikanya. Salah satu faktor hidrodinamika yang penting ...adalah pola alir dalam reaktor. Penelitian ini bertujuan mempelajari pola alir fasa cair dalam reaktortrickel bed dan memodelkan alirannya untuk berbagai kondisi operasi (laju alir gas dan laju alir cairan). Reaktor trickle bed yang digunakan dalm percobaan ini terdiri dari kolom acrylic yang berdiameter dalam 4,8. 10-2 m dengan tinggi 7.10-2 m dengan menggunakan packing karbon aktif granular (drata-rata = 0,476 cm). Kondisi operasinya adalah laju alir gas antara 1,33- 2,4. 10-4 m3/s, laju alir cairan antara 1,2-2,37. 10-5 m3/s, tekanan atmosferik dan suhu kamar (29 0C). Metode stimulus response digunakan untuk memperoleh distribusi waktu tinggal dengan menggunakan laruan NaCl sebagai pelacak yang diinjeksikan secara pulse pada bagian masuk reaktor dan konsentrasi keluar reaktor diukur dengan menggunakan konduktometer. Kurva distribusi waktu tinggal yang diperoleh dicocokkan dengan model dispersed plug-flow dan model tanki seri, dengan bilangan disperse (D/μL) dan bilangan tanki (N) sebagai parameter model. Hasil eksperimen menunjukkan bahwa distribusi waktu tinggal sangat dipengaruhi oleh laju alir cairan dan sedikit dipengaruhi laju alir gas dalam reaktor. Kedua model menunjukkn kecocokan dengan data percobaan, namun model tanki seri lebih baik. Harga bilangan disperse (D/μL) yang diperoleh dalam reaktor ini berkisar 0,075-0,104 dan bilangan tanki seri (N) berkisar antara 5,4-7,2; yang menunjukkan bahwa reaktor tersebut tidak berada dalam pola alir ideal (plugflow atau mixedflow). Bilangan disperse menurun secara signifikan dengan meningkatnya laju alir cairan, tetapi sedikit dengan lajualir gas.Kata kunci : reaktor trickle bed, pola alir, disperse plug flow, tanki seri
The Yellow-legged Buttonquail Turnix tanki is a species of the genus Turnix, which belongs to the order Charadriiformes. It is distributed across almost all of China. The International Union for ...Conservation of Nature has assessed the bird's conservation status as 'Least Concern (LC).' We sequenced the complete mitogenome of T. tanki and examined its phylogenetic relationship with other charadriiformes species. The mitochondrial DNA is packaged in a compact 17,620 base pair circular molecule with A + T content of 57.90%. It contains 37 typical mitochondrial genes, including 13 protein-coding genes, two rRNAs and 22 tRNAs, and two non-coding regions. We reconstructed a phylogenetic tree based on mitogenome sequences of five Turnicidae species and one outgroup. Phylogenetic analysis indicated that T. tanki is a sister to T. suscitator.
Mikrovlačno je ispitivanje varijanta standardnoga vlačnog ispitivanja provedeno na malim probama. Često nazivano „metodom tankih listića“, ispitivanje čvrstoće na vlak mikrotomiranih vrlo tankih ...furnira u ovom se članku opisuje uz posebno razmatranje polja primjene te metode, kao i uz komentare o pouzdanosti i varijabilnosti rezultata. Članak također predstavlja eksperimentalne detalje i naputke za provođenje metode visoke preciznosti. Prednost te metode očituje se u činjenici da je longitudinalne tanke mikrotomirane odječke moguće zaštićivati različitim sredstvima (primjerice, impregnirati sredstvima za površinsku zaštitu), potom izlagati različitim utjecajima starenja i, konačno, podvrgnuti ispitivanju čvrstoće na vlak. Male dimenzije individualnih proba omogućuju ispitivanja na velikom uzorku. Ispitivanja na nultome početnom rasponu ispitnih čeljusti uvelike odražavaju mehanička svojstva celuloze, dok ispitivanja na određenom (najčešće 10-milimetarskom) rasponu daju informacije o ukupnim svojstvima materijala – ne samo o svojstvima mikrofibrila nego i o svojstvima veziva (lignina i hemiceluloze). Postupci izbora, pripreme, mikrotomiranja, uzorkovanja, izlaganja i ispitivanja opisani u ovom radu ključni su za postizanje velike pouzdanosti (niskih koeficijenata varijacije), kako pri ponavljanju, tako i pri obnavljanju ispitivanja. Pravilno je mikrotomiranje, pak, ključan korak u procesu pripreme materijala, dok kontrola debljine osigurava kvalitetu pripremljenog materijala, a time i pouzdane i točne rezultate. Nedostatak opisane metode jest to što je praktična primjenjivost smanjena na mali broj vrsta drva. Nadalje, metoda zahtijeva veliku vještinu i pozornost operatera pri pripremi materijala, provođenju ispitivanja i interpretaciji rezultata. Metoda je tehnički zahtjevna, a pokusi mogu biti dugotrajni. Unatoč tome, primjena te metode relativno je brz i pouzdan način ocjene kemijskih i strukturnih promjena, kao i ispitivanja biološke razgradnje tankih slojeva drva.
Abstrak : Suatu tangki penyimpanan air panas yang dalam kasus ini terbuat dari baja nirkarat (stainless steel)mengalami kegagalan karena korosi terutama pada bagian sambungan las. Korosi juga ...terjadipada bagian bawah tanki. Tanki telah digunakan kurang lebih di bawah satu tahun namun sudahmengalami korosi parah terutama pada bagian sambungan las dan juga mengalami korosi padabagian bawah. Penelitian ini bertujuan mengetahui penyebab terjadinya korosi. Penelitiandilakukan dengan menggunakan teknik pengamatan metalografi langsung dilapangan denganmenggunakan mikroskop metalurgi portable. Hasil pengujian menunjukkan korosi terjadi akibatkorosi galvanik yaitu sambungan dua jenis logam nirkarat yang berbeda dan diperparah denganterjadinya korosi pitting. Pengujian dengan menggunakan sinar X fluorisensi juga membuktikanbahwa pelat bagian bawah tanki dan pelat bagian samping dan atas ternyata memiliki kandunganyang berbeda. Untuk mengatasi hal ini maka teknik pengelasan harus ditingkatkan denganmenggunakan logam pengisi yang tepatKata kunci: tanki, air panas, korosi, baja nirkarat, galvanik, pitting Abstract : Hot water storage tank that was made from stainless still was investigated in this case. The tankwas found failure in service due to corrosion in welded section. Corrosion also was found at thebottom part of the storage tank. The tank was used for no longer than one year but unfortunatelysevere corrosion was found. The purpose of this research is to find the reason why the tank easilycorroded especially at the bottom part and at the welding section. The research was carried out byconducting metallographic examination directly in situ by utilizing portable metallographicmicroscope. It is found from investigation that the corrosion was happen due to galvanic corrosion.Investigation by using X ray fluorescence also agree that the composition of the bottom part of thetank was different with the wall, and upper section. The welding filler also was found not correctlyprepared that make pitting corrosion to occur. It is suggested to conduct advance research toinvestigate the correct composition for the filler during welding.Key word: Tank, hot water, corrosion, stainless steel, galvanik,pitting
The Andalusian hemipode (Turnix sylvatica sylvatica) (Order: Turniciformes, Family: Turnicidae), formerly distributed in several Mediterranean countries, is a critically endangered bird, if not ...already extinct. Subspecies of the T. sylvatica complex, in turn composed by nine subspecies are widely distributed in Africa and southern Asia. The last free-ranging Andalusian hemipodes were shot by hunters near Doñana National Park (Spain) in 1981. Therefore, this species could be the last bird species getting extinct in Iberia and Europe in the XXth century. This investigation deals with the phylogenetic relationships of the Andalusian hemipode with the supposedly congeneric T. varia , T. tanki , T. suscitator and T. pyrrhothorax, and with the supposedly conspecific T. sylvatica lepurana, which is the geographically nearest buttonquail population (occurring in central and southern Africa). A 606 bp long fragment of the cytochrome b gene (approx. 1140 bp) of the mitochondrial DNA was sequenced, using both museum skins (the only available source for T. s. sylvatica) or blood/tissue samples from contemporary individuals (remaining species and subspecies). Seven haplotypes were found: two each for T. varia and T. s. lepurana, and one each for T. tanki, T. suscitator, T. pyrrhothorax, and T. s. sylvatica. Sequence divergence values obtained from pairwise distances between the T. sylvatica group haplotypes and the other species, ranged from 19.4 to 25.9%. The low genetic divergence between T. s. sylvatica and T. s. lepurana (0.00–0.01%) confirmed that the current classification based on morphological characters is correct, and that these two taxa may should be considered as subspecies. This close relationship would permit an introduction T. sylvatica where the species was last seen in Spain (i.e., Doñana National Park). This area is now strictly protected and human persecution is no longer a problem.
Pemakaian kapal sebagai sarana distribusi LNG ke berbagai wilayah merupakan salah satu cara yang menguntungkan dan efisien. Penggunaan kapal sebagai sarana distribusi LNG membuat hal-hal yang ...berhubungan dengan tangki kapal menjadi menarik untuk diteliti. Salah satu yang paling banyak diteliti adalah fenomena sloshing. Simulasi gerakan fluida pada tanki dilakukan dalam time-domain. Gelombang pada saat kapal berlayar di laut tidak dapat diprediksi dengan akurat. Gelombang yang datang dengan sudut hadap 90o (beam sea) dapat menimbulkan gerakan rolling yang sangat berpengaruh pada gerakan fluida di dalam tangki atau sering disebut fenomena sloshing. Gerakan fluida ini menimbulkan gaya berupa tekanan pada dinding tangki berupa dynamic pressure. Tangki jenis membrane banyak digunakan pada kapal LNG. Sehingga, banyak penelitian yang berkaitan dengan tangki membrane. Tangki membrane dimodelkan 3D dengan menggunakan software maxsurf yang berukuran panjang 32.46 m, tinggi 27.32 m dengan lebar moulded belakang 39.17 m, lebar belakang bagian bawah 31.29 m, lebar belakang bagian atas 31.29 m. lebar moulded depan 39.17 m, lebar depan bagian bawah 31.29 m, lebar depan bagian atas 31.29 m. Volume cairan LNG divariasikan dengan 3 (tiga) ketinggian yaitu ketinggian cairan 30% dari tinggi tangki, 50% dari tinggi tangki, dan 80% tinggi tanki. Analisa dilakukan dengan menggunakan software Ansys Fluent dengan metode Computational Fluid Dynamic (CFD). Dari hasil analisa dengan ansys fluent dapat disimpulkan bahwa dynamic pressure terbesar terjadi pada filling level 30% H dalam tanki yaitu sebesar 16513.720 Pa yang terjadi pada bagian kanan dinding tanki pada ketinggian 8,655 m dari dasar tank
Provider: - Institution: - Data provided by Europeana Collections- Titanium-nitride (TiN) thin film structures research is of great importance because of the unique combination of physical and ...chemical properties of this material. TiN is a material commonly used in various fields of technology due to the properties such as high hardness, high melting point, good corrosion and abrasion resistance, high electrical conductivity, low contact resistance, etc. The process of ion implantation can be used to change the properties of deposited TiN structures. It is a non-equilibrium process by precise control of parameters such as type, concentration and energy of implanted ions. In this way ion implantation can produce changes in crystal structure of materials, produce of amorphization, creation of nano-inclusions, compounds, changes in surface morphology, etc. These changes can alter physical, chemical, mechanical, optical and other properties of materials. In this work titanium nitride thin films with 240.nm thickness were obtained using reactive sputtering. The substrates used were monocrystalline (100) Si wafers. During deposition the substrates were held at room temperature or at 150ºC. Modification of the deposited layers was performed using the ion implantation technique. The samples were irradiated with 120keV and 200keV gaseous argon ions and 80.keV metal vanadium ions. In the case of argon ions the fluences were in the range of 5×1015– 20×1015 ions/cm2, whereas for the vanadium ions the fluences were 1×1017 ions/cm2 and 2×1017 ions/cm2. The main objective of this experimental research is to study the influence and to compare the differences of incident inert and metal ions on the structural, electrical and optical properties of titanium nitride layers. The influence of the substrate temperature on the structure of as deposited thin films was also examined. v Stoichiometry, homogeneity and thickness of TiN thin layers before and after implantation of argon and vanadium ions was analyzed using Rutherford backscattering spectrometry (RBS). This analysis showed that the implantation of argon ions did not caused any changes in stoichiometric ratio of components in TiN layers even after highest ion fluences. In the case of vanadium implantation the layer exhibit nonstoichiometric concentration profiles in the region where the mostly vanadium ions are stopped as well as in the region beneath of the implanted zone. It was also found that the vanadium ions induced the increase of the effective thickness of the films. Structural analysis of thin layers was done by means of X-ray diffraction (XRD), transmission electron microscopy in combination with selected area electron diffraction (TEM/SAD) and high resolution TEM combined with fast Fourier transforms (HRTEM/FFT). These methods enabled us to identify phases present in the deposited and implanted structures. We found that the TiN layers grow in the form of a very fine polycrystalline columnar structure. After argon ion irradiation the layers retain their polycrystalline structure, but the columnar grains were disconnected. XRD and FFT analysis have shown only the presence of face-centered cubic TiN phase with a decrease of grains after argon ion implantation. Hence, ion implantation induced only local atomic rearrangements within the films. In the case of vanadium ions TEM analysis showed the presence of amorphous layer above the implanted region. Implanted region with a polycrystalline structure contains a large amount of defects. In the area where the most of the vanadium ions stopped, XRD and FFT analysis showed the presence of face-centered cubic TiN phase as well as the presence of a new VN phase. It can be concluded that the implantation of vanadium ions leads to the formation of new phase due to chemical effects. It was also observed that the depth of damage was significantly greater than those provided with SRIM2003 simulation. Four-point probe method showed that the resistivity increases with increasing ion fluence. Optical measurements obtained by IR analysis have shown that the changes in optical resistivites have the same trend as the changes in specific resistivites. The variations of specific and optical resistivites are due to the accumulation of vi defects after argon ion implantation and the formation of new phase after vanadium implantation.- Istraživanja tankoslojnih struktura titan-nitrida (TiN) su od izuzetnog značaja zbog jedinstvene kombinacije fizičkih i hemijskih svojstava koje ovaj materijal poseduje. Titan-nitrid je materijal koji ima primenu u različitim oblastima tehnologije zahvaljujući svojstvima kao što su visoka tvrdoća, visoka tačka topljenja, dobar otpor na habanje i koroziju, visoka električna provodnost, mali kontaktni otpor, itd. Svojstva deponovanih TiN struktura je moguće kontrolisano menjati primenom jonske implantacije. To je neravnotežni proces u kome je moguća precizna kontrola parametara kao što su vrsta, energija i koncentracija ugrađenih jona. Na taj način jonska implantacija može dovesti do promene kristalne strukture materijala, amorfizacije, stvaranja nano-uključaka, jedinjenja, promene morfologije površine, itd. Nabrojane strukturne promene mogu da menjaju fizička, hemijska, mehanička, optička i druga svojstva materijala. U okviru ovog rada tankoslojne strukture TiN debljine -240nm dobijene su metodom reaktivnog jonskog rasprašivanja. Kao podloge su korišćene monokristalne (100) silicijumske pločice. Slojevi TiN su deponovani na sobnoj temperaturi podloge i na temperaturi podloge od T-150ºC. Modifikacija deponovanih slojeva urađena je tehnikom jonske implantacije. Uzorci su ozračivani gasovitim jonima argona energije 120keV i 200keV i metalnim jonima vanadijuma energije 80keV. Jonske doze su u slučaju jona argona bile u opsegu 5×1015 –20×1015 jona/cm2, dok su za jone vanadijuma doze bile 1×1017 jona/cm2 i 2×1017 jona/cm2. Osnovni cilj ovih eksperimentalnih istraživanja je proučavanje uticaja i poređenje razlike uticaja inertnog i metalnog upadnog jona na strukturna, električna i optička svojstva TiN slojeva. Pored toga, proučavan je i uticaj temperature podloge na strukturu deponovanih tankih slojeva TiN. II Stehiometrija, homogenost i debljina tankih slojeva TiN pre i posle implantacije jonima argona i vanadijuma analizirana je metodom Rutherford-ovog povratnog rasejanja (RBS). Analiza pokazuje da joni argona nisu prouzrokovali promene stehiometrijskog odnosa komponenata u TiN sloju cak ni posle najveće doze argona. U slučaju implantacije jonima vanadijuma sloj pokazuje nestehiometrijske koncentracione profile u oblasti gde se najveći broj jona vanadijuma zaustavio kao i u oblasti ispod implantirane zone. Takođe je zapaženo da joni vanadijuma dovode do porasta efektivne debljine sloja. Strukturna analiza tankih slojeva je urađena difrakcijom X zraka (XRD), transmisionom elektronskom mikroskopijom u kombinaciji sa elektronskom difrakcijom na odabranoj površini (TEM/SAD) i visokorezolucionom elektronskom mikroskopijom uz analizu pomoću Fourier-ove transformacije (HRTEM/FFT). Ove metode su nam omogućile da definišemo prisustvo faza u deponovanim i implantiranim strukturama. Uočili smo da TiN slojevi rastu u vidu vrlo fine polikristalne stubičaste strukture. Nakon implantacije jonima argona slojevi zadržavaju polikristalnu strukturu uz narušavanje stubičaste strukture u oblasti oštećenja uzrokovanog implantacijom. XRD i FFT analiza je pokazala da je prisutna samo površinski centrirana kubna TiN faza uz smanjenje veličine zrna nakon implantacije jonima argona. Dakle, jonsko zračenje dovodi samo do lokalnog atomskog preuredivanja unutar sloja. U slučaju jona vanadijuma TEM analiza pokazuje prisustvo amorfnog sloja iznad implantirane oblasti. Implantirana oblast koja ima polikristalnu strukturu sadrži veliku količinu defekata. XRD i FFT analize su pokazale pored površinski centrirane kubne TiN faze prisustvo nove VN faze u oblasti gde se najveći broj jona vanadijuma zaustavio. Može se zaključiti da implantacija jonima vanadijuma dovodi do formiranja nove faze usled hemijskih efekata. Takođe je primećeno da je dubina oštećenja značajno veća od one predvidene SRIM2003 simulacijom. Metoda „četiri tačke” pokazuje da specifična otpornost raste sa porastom jonske doze. Optička merenja IR metodom su pokazala da optička otpornost prati promenu specifične otpornosti. Efekat promene specifične i optičke otpornosti je objašnjen III akumulacijom defekata implantacijom jona argona i formiranjem nove faze u slučaju jona vanadijuma.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Semakin tahun populasi penduduk di Indonesia selalu meningkat sehingga kebutuhan konsumsi energi listrik begitu tinggi. Di Indonesia, pembangkit listrik banyak menggunakan bahan bakar fosil sebagai ...bahan bakar utama, padahal potensi energi alternatif dan ramah lingkungan di Indonesia dapat dimaksimalkan, misalnya energi gelombang laut. Pada penelitian ini difokuskan pada evaluasi kinerja sistem pembangkit listrik tenaga gelombang laut menggunakan tanki bertekanan dan multiple OWC (Oscillating Water Column). Pada percobaan yang telah dilakukan, dengan tekanan 4.5 bar pada tanki bertekanan dengan volume 0.5 m3, putaran yang dihasilkan generator adalah 1876 rpm dan daya luaran generator yang dihasilkan adalah 168 watt. Waktu pengisian tanki bertekanan lebih efektif jika menggunakan multiple OWC (Oscillating Water Column)
Provider: - Institution: - Data provided by Europeana Collections- Thin film structures own significantly different properties than the bulk
material and consequently they found applications in ...various fields of modern
nanotechnology. In the past few decades, special attention was paid to
research in the field of ion beams modification of thin films. Among the
techniques ion implantation is particularly emphasized, as a method that
allows the incorporation of impurity atoms in the material with the
possibility of precise control of process parameters. As non-equilibrium
technique (not controlled by diffusion laws), ion implantation enables
production of a new materials, that can not be produced with other
conventional methods. The main objective of this research was to gain new
fundamental knowledge in the field of modification of thin film/Si systems
induced by ion irradiation. The present work consists of two parts. In the
first part of the experiment the changes induced by ion implantation inside
of the thin layer were examined – effects of different ionic species on the
microstructure, optical and electrical properties of chromium nitride (CrN)
were investigated. The second part of the experiment refers to the
examination of changes at the thin film/substrate interface due to ion
implantation – the influence of ion bombardment on the ion beam mixing of
Co/Si system was investigated as well as formation of cobalt-silicides during
the process of ion irradiation and./.or annealing of the samples. Rutherford
backscattering spectrometry (RBS) was used to obtain concentration depth
profiles of elements and to determine the stoichiometry of the layers.
Structural and phase analyses of the systems were performed by X-ray
diffraction (XRD), transmission electron microscopy combined with selected
area diffraction (TEM/ SAD) and high-resolution electron microscopy analysis
together with fast Fourier transformations (HRTEM/FFT). Optical properties of
modified CrN layers were determined using infrared spectroscopy (IR) and
electrical resistivity was measured using four point probe method. CrN thin
films (thickness of ~280 nm) were deposited by reactive sputtering on
crystalline silicon substrates and then implanted with 200 keV Ar+ and 80 keV
V+ ions. In the case of Ar+ ions the samples were implanted in the range of
5×1015–20×1015 ions/cm2, while V+ ions were implanted to the fluence of
1×1017 and 2×1017 ions/cm2. The energies were chosen in such a way that all
ions are stopped inside the layer, to avoid any atomic mixing and possible
reactions at the thin film./.substrate interface. It turned out that
different ionic species produces different effects in the layer, which is
manifested in both the microstructural changes, as well as changes in optical
and electrical properties of this material. After irradiation with Ar+ ions
there are no significant changes in the composition of the layer. However,
the changes were observed in the microstructure of the samples. In the
implantation region the initial columnar structure of the layer firstly
becomes broken and with increasing of ion fluence completely destroyed. The
accumulation of defects within this area produces damage and the internal
stresses in the layer, which affects the size of crystalline grains and the
values of the CrN lattice constant. In contrast to the implantation of inert
argon which produces only ion irradiation induced damage, the presence of
vanadium, as the second transition metal, leads to the generation of chemical
effects in the layer. It was observed that in the region of the layer with
the highest concentration of implanted vanadium Cr0,9375 V0,0625N compound
was formed. Due to the formation of a new metallic phase, as deposited CrN
layer with metal/semiconductor properties shows a purely metallic character
after V+ implantation. Co(50nm)/Si bilayers were prepared in high vacuum
conditions, using ion beam assisted deposition technique. Two types of
silicon substrates were used: crystalline (100) wafers and Si wafers
pre-amorphized by low-energy Ar+ ion bombardment. After deposition the layers
were implanted with 400 keV Xe+ ions to the fluence of 2×1015, 4×1015,
6×1015, 8×1015, 10×1015, 15×1015, 20×1015 and 30×1015 ions/cm2. The energy
was chosen so that the effects of ion implantation are most pronounced at the
thin film (Co)./.substrate (Si) interface. Then, as deposited and selected
implanted samples (20×1015 Xe/cm2) were annealed for 2.h in the vacuum
furnace at 200, 300, 400, 500, 600 and 700ºC. The values of atomic mixing
rates showed that the structure of the substrate has a strong influence on
the process of atomic transport induced by ion bombardment. Namely, in the
case of pre-amorphized substrate the mixing rate of Co and Si atoms at the
Co/Si interface is almost for an order of magnitude lower in comparation with
crystalline Si. It is assumed that this is the result of the formation of
large amount of defects, created near the surface of Si substrate during the
Ar+ ions bombardment, which presents a barrier for movement of atoms from one
to the other side of the interface. Low mobility of these defects prevents
also the thermally activated diffusion, so even at the highest annealing
temperature the formation of silicides was not observed. For the irradiated
samples, independently on whether it is crystalline or pre-amorphized
substrate, it is observed similar behavior: up to annealing temperatures of
400ºC poorly pronounced diffusion comes from the effects induced by ion
irradiation, and at temperatures of 500–700ºC thermal mixing becomes dominant
process and conditions for the compound formation were fulfilled. At the
temperature of 500ºC dominant phase is CoSi, and at temperatures ≥600ºC a
pure phase CoSi2 was formed.- Zbog činjenice da posjeduju svojstva koja se znatno razlikuju od komadnog
materijala, tankoslojne strukture su našle primjenu u raznim oblastima
savremenih nanotehnologija. U posljednjih nekoliko decenija posebna pažnja je
posvećena istraživanjima na polju modifikacije tankih slojeva korišćenjem
jonskih snopova. Medu tehnikama se posebno istakla jonska implantacija, kao
metoda koja omogućuje ugrađivanje atoma nečistoća u materijal u strogo
kontrolisanim uslovima. Kao neravnotežna tehnika (nije kontrolisana zakonima
difuzije), jonska implantacija omogućuje dobijanje novih materijala, koji se
drugim postupcima ne mogu formirati. Osnovni cilj ovog istraživanja je
sticanje novih fundamentalnih znanja u oblasti modifikacije sistema tanak
sloj/Si primjenom jonskog zračenja. Predstavljeni rad se sastoji iz dva
dijela. U prvom dijelu eksperimenta su posmatrane promjene koje jonska
implantacija indukuje unutar tankog sloja – ispitivan je efekat različitih
jonskih vrsta na mikrostrukturu, optička i električna svojstva hrom-nitrida
(CrN). Drugi dio eksperimenta se odnosi na ispitivanje promjena koje uslijed
jonske implantacije nastaju na granici tanak sloj/podloga – proučavan je
uticaj jonskog bombardovanja na proces atomskog transporta kod Co/Si sistema
i mogućnost formiranja kobalt-silicida u toku procesa jonskog zračenja i/ili
odgrijavanja uzoraka. Spektrometrija Rutherford-ovim povratnim rasijanjem
(RBS) je iskorišćena za dobijanje dubinskih koncentracionih profila elemenata
i određivanje stehiometrije slojeva. Za strukturnu analizu i identifikaciju
prisutnih faza u uzorcima korišćena je difrakcija X-zračenja (XRD),
transmisiona elektronska mikroskopija u kombinaciji sa elektronskom
difrakcijom na odabranoj površini (TEM/SAD) i visoko-rezoluciona elektronska
mikroskopija uz analizu pomoću Fourier-ove transformacije (HRTEM/FFT).
Optička svojstva modifikovanih CrN slojeva su određena korišćenjem
infracrvene spektrofotometrije (IR), a električna otpornost je mjerena
metodom ”četiri tačke”. Tanki slojevi CrN (debljine ~280 nm) su deponovani
metodom reaktivnog jonskog rasprašivanja na kristalnim silicijumskim
pločicama, a zatim su implantirani sa 200 keV Ar+ i 80 keV V+ jonima. U
slučaju Ar+ jona uzorci su implantirani u opsegu od 5×1015–20×1015 jona/cm2,
dok su joni V+ implantirani do doze 1×1017 i 2×1017 jona/cm2. Energije su
odabrane tako da se svi joni zaustave u sloju, da bi se izbjeglo atomsko
miješanje i moguće reakcije na granici sloj/podloga. Pokazalo se da različite
jonske vrste proizvode drugačije efekte u sloju, što se manifestovalo kako u
mikrostrukturnim promjenama, tako i u promjenama optičkih i električnih
svojstava ovog materijala. Nakon ozračivanja sa jonima Ar+ ne dolazi do
značajnih promjena u sastavu sloja. Međutim, uočene su promjene u
mikrostrukturi uzoraka. U zoni implantacije prvo dolazi do narušavanja, a sa
povećanjem doze i do potpunog uništenja prvobitne stubičaste strukture sloja.
Nakupljanje defekata unutar ove oblasti proizvodi oštećenja i unutrašnja
naprezanja u sloju, što utiče na veličinu kristalnih zrna i na vrijednost
konstante CrN rešetke. Za razliku od implantacije inertnog argona gdje dolazi
samo do pojave jonskim zračenjem indukovanog oštećenja, prisustvo vanadijuma,
kao drugog prelaznog metala, dovodi do pojave hemijskih efekata u sloju.
Uočeno je da u zoni sloja sa najvećom koncentracijom implantiranog vanadijuma
dolazi do formiranja Cr0,9375 V0,0625.N jedinjenja. Formiranje nove metalne
faze ima za posljedicu da deponovani CrN sloj sa metalno/poluprovodničkim
svojstvima, nakon V+ implantacije pokazuje izraziti metalni karakter.
Dvoslojni sistemi Co(50nm)/Si su pripremljeni u uslovima visokog vakuuma,
korišćenjem metode deponovanja potpomognutog jonskim snopom. Korišćene su
dvije vrste silicijumskih podloga: kristalne pločice orijentacije (100) i
podloge sa površinom amorfizovanom bombardovanjem sa niskoenergetskim Ar+
jonima. Nakon deponovanja slojevi su implantirani sa 400 keV Xe+ jonima do
doze 2×1015, 4×1015, 6×1015, 8×1015, 10×1015, 15×1015, 20×1015 i 30×1015
jona/cm2. Energija je odabrana tako da efekti jonske implantacije budu
najizraženiji na granici tanak sloj (Co)/podloga (Si
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