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"ABSTRAKHidroksiapatit (HAp) dengan rumus senyawa kimia Ca10(PO4)6(OH)2 merupakan bahan pengganti tulang yang digunakan dalam teknologi alternatif cangkok tulang. Hidroksiapatit memiliki sifat seperti biokompatibilitas, bioaktif dan tidak beracun sehingga aman bagi tubuh manusia. Penelitian ini bertujuan untuk menganalisis pengaruh variasi pH dan waktu terhadap sintesis hidroksiapatit dengan menggunakan iradiasi gelombang mikro dan sintering. Hasil menunjukan variasi pH dan waktu mempengaruhi ukuran kristal, derajat kristalinitas dan bentuk morfologi. Karakterisasi XRD menunjukan sampel yang diiradiasi oleh gelombang mikro selama 25 menit menghasilkan ukuran kristal tertinggi sekitar 21,60 nm pada pH 7. Proses sintering menghasilkan ukuran kristal tiga kali lipat dan ukuran kristal tertinggi mencapai sekitar 59,07 nm pada pH 11. Karakterisasi XRD juga menunjukan bahwa variasi pH memunculkan fase sekunder berupa chlorapatit. Karakterisasi FTIR menunjukan dengan adanya proses sintering menghilangkan gugus karbonat dan karakterisasi SEM-EDX pada pH 11 yang hanya diiradiasi gelombang mikro menunjukan partikel berbentuk bulat dan beraglomerasi ukuran partikel sekitar 63,43 nm dengan rasio Ca/P adalah 1,59 dan proses sintering menghasilkan bentuk partikel lebih kristalin ukuran partikel mencapai 180,62 nm dengan rasio Ca/P adalah 1,48. Penggunaan suhu tinggi berpengaruh terhadap pertumbuhan kristal dalam sintesis hidroksiapatit."

"Sintesis hidroksiapatit adalah senyawa anorganik yang membentuk bagian yang sulit jaringan tubuh manusia seperti tulang. Materi ini bertindak sebagai biokompatibilitas, bioaktivitas, dan osteokonduktivitas, sehingga membuat hidroksiapatit (HA) cocok sebagai a biomaterial. Penelitian ini bertujuan untuk menggantikan ion Magnesium (Mg), yang memiliki peran penting dalam struktur dan fungsi tubuh manusia, dalam Kalsium (Ca) ion dari Hidroksiapatit. Kristal MgHA disintesis dengan mencampurkan larutan diammonium hidrogen fosfat dan magnesium hidroksida menjadi kalsium larutan hidroksida yang kemudian diiradiasi dengan gelombang mikro, dengan variasi dalam konsentrasi Mg dan waktu iradiasi. Dari hasil XRD menunjukkan bahwa sepanjang dengan peningkatan konsentrasi Mg dan waktu iradiasi parameter kisi nilai a dan c dikurangi sebesar 0,03 dalam kisi a dan 0,01 dalam kisi c. Peningkatan Waktu iradiasi sebanding dengan peningkatan ukuran kristal (L) dan kristalinitas indeks (CI). Pada t = 35 ditemukan L = 19,08 nm dan CI = 0,14. Peningkatan Mg konsentrasi sebanding dengan peningkatan ukuran kristal dan indeks kristalinitas, peningkatan konsentrasi Mg di atas 0,6 M menunjukkan adanya saturasi dalam proses pengikatan Mg dalam struktur apatit. Proses sintering pada 900ºC meningkatkan nilai ukuran kristal dari 19,08 nm menjadi 52,09 nm dan kristalinitas indeks dari 0,14 menjadi 2,97. Dengan morfologi MgHA menghasilkan partikel berbentuk batang aglomerasi disebabkan oleh sejumlah besar konten Mg dalam apatit.

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Hydroxyapatite synthesis is an inorganic compound that forms a difficult part of human body tissue such as bone. This material acts as biocompatibility, bioactivity, and osteoconductivity, thus making hydroxyapatite (HA) suitable as a biomaterial. This research aims to replace Magnesium (Mg) ions, which have an important role in the structure and function of the human body, in Calcium (Ca) ions from Hydroxyapatite. MgHA crystals are synthesized by mixing a solution of diammonium hydrogen phosphate and magnesium hydroxide into calcium hydroxide solution which is then irradiated with microwaves, with variations in Mg concentration and irradiation time.

The XRD results show that along with the increase in Mg concentration and irradiation time the lattice parameter values ​​a and c are reduced by 0.03 in lattice a and 0.01 in lattice c. The increase in irradiation time is proportional to the increase in crystal size (L) and crystallinity index (CI). At t = 35 found L = 19.08 nm and CI = 0.14. An increase in Mg concentration is proportional to an increase in crystal size and crystallinity index, an increase in Mg concentration above 0.6 M indicates the presence of saturation in the Mg binding process in apatite structures. The sintering process at 900ºC increased the crystal size value from 19.08 nm to 52.09 nm and the crystallinity index from 0.14 to 2.97. With morphology, MgHA produces agglomeration rod-shaped particles caused by large amounts of Mg content in apatite."

"[ABSTRAKHidroksiapatit (HA) mempunyai peran penting dalam bidang medis karena komposisi kimia dan strukturnya yang mirip dengan tulang manusia. Material ini disintesis melalui metode hidrotermal dengan prekusor Ca(NO3)2, CaO dan NH3PO4. Variasi temperatur hidrotermal pada 150 ̊C dan 300 ̊C, temperatur sintering pada 900 ̊C selama 3 jam. Endapan yang diperoleh diuji dengan XRD dan SEM-EDX. Morfologi partikel hasil karakterisasi SEM berbentuk batangan memanjang dan melingkar teraglomerasi dan hasil uji EDX menunjukkan rasio Ca/P yang lebih besar dari 1.67. Uji XRD menunjukkan adanya fasa kalsium difosfat, fluorapatit dan apatit karbonat tipe- A di dalam endapan yang meningkatkan rasio Ca/P.ABSTRACTHydroxyapatite (HA) posseses significant role in medical application due to its similarity in chemical and structure to human bones. This material was synthesized through hydrothermal method using Ca(NO3)2, CaO and NH3PO4. Hydrothermal temperature varied on 150 ̊C and 300 ̊C, sintering temperature on 900 ̊C for 3 hours. Sample was characterization by XRD and SEM-EDX. Morphology observed by SEM is agglomerated round- spherical- shape particle with Ca/P ratio more than 1.67 measured by EDX. Calcium diphospate, fluorapatite and carbonated type- A presence is observed by XRD.;Hydroxyapatite (HA) posseses significant role in medical application due to its similarity in chemical and structure to human bones. This material was synthesized through hydrothermal method using Ca(NO3)2, CaO and NH3PO4. Hydrothermal temperature varied on 150 ̊C and 300 ̊C, sintering temperature on 900 ̊C for 3 hours. Sample was characterization by XRD and SEM-EDX. Morphology observed by SEM is agglomerated round- spherical- shape particle with Ca/P ratio more than 1.67 measured by EDX. Calcium diphospate, fluorapatite and carbonated type- A presence is observed by XRD., Hydroxyapatite (HA) posseses significant role in medical application due to its similarity in chemical and structure to human bones. This material was synthesized through hydrothermal method using Ca(NO3)2, CaO and NH3PO4. Hydrothermal temperature varied on 150 ̊C and 300 ̊C, sintering temperature on 900 ̊C for 3 hours. Sample was characterization by XRD and SEM-EDX. Morphology observed by SEM is agglomerated round- spherical- shape particle with Ca/P ratio more than 1.67 measured by EDX. Calcium diphospate, fluorapatite and carbonated type- A presence is observed by XRD.]"

"[ABSTRAKHroksiapatit merupakan jenis biomaterial sintetis yang mempunyai fasa yang paling stabil dibandingkan dengan senyawa kalsiun fosfat lainnya, selain itu hidroksiapatit memiliki tingkat kemiripan yang tinggi dengan tulang, sehingga hidroksiapatik banyak diaplikasikan sebagai bone graft sintetis. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh waktu sintering terhadap kemurnian kristal hidroksiapatit yang dihasilkan. Hidroksiapatit dari prekursor kimia CaCO3 dan (NH4)2HPO4 disintesis dengan menggunakan metode hidrotermal pada temperatur 150oC dan 300oC. Hasil dari sintesis hidroksiapatik dikarakterisasi dengan menggunakan X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), dan Energy Dispersive Analysis X-Ray (EDX). Hasil karakterisasi XRD memperlihatkan intensitas tertinggi rata-rata berada pada sudut 2θ yaitu, 25.898o, 31.789o, 32.216o, 32.922o, 46.729o, dan 49.524o. Hasil dari SEM memperlihatkan morfologi dari sampel bebrbetuk nanoroot dan hasil dari EDX menunjukan rasio Ca/P sebesar 1.8.ABSTRACTHydroxyapatite is the most phase-stable syntetic biomaterial compared to another calcium phospate material. Hydroxyapatite also has high similarity with bone which make it has wide application as syntetic bone graft. Purpose of this research is to study the effect of sintering time towards hydroxyapatite crystal?s purity. Hydroxyapatite made from chemical precursor CaCO3 and (NH4)2HPO4 was synthesized using hydrothermal method on 150oC and 300oC. Synthesized hydroxyapatite was characterized using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive Analysis X-Ray (EDX). The result of characterization showed that highest average intensity on 2θ were: 25.898o, 31.789o, 32.216o, 32.922o, 46.729o, and 49.524o.;Hydroxyapatite is the most phase-stable syntetic biomaterial compared to another calcium phospate material. Hydroxyapatite also has high similarity with bone which make it has wide application as syntetic bone graft. Purpose of this research is to study the effect of sintering time towards hydroxyapatite crystal?s purity. Hydroxyapatite made from chemical precursor CaCO3 and (NH4)2HPO4 was synthesized using hydrothermal method on 150oC and 300oC. Synthesized hydroxyapatite was characterized using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive Analysis X-Ray (EDX). The result of characterization showed that highest average intensity on 2θ were: 25.898o, 31.789o, 32.216o, 32.922o, 46.729o, and 49.524o.;Hydroxyapatite is the most phase-stable syntetic biomaterial compared to another calcium phospate material. Hydroxyapatite also has high similarity with bone which make it has wide application as syntetic bone graft. Purpose of this research is to study the effect of sintering time towards hydroxyapatite crystal?s purity. Hydroxyapatite made from chemical precursor CaCO3 and (NH4)2HPO4 was synthesized using hydrothermal method on 150oC and 300oC. Synthesized hydroxyapatite was characterized using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive Analysis X-Ray (EDX). The result of characterization showed that highest average intensity on 2θ were: 25.898o, 31.789o, 32.216o, 32.922o, 46.729o, and 49.524o., Hydroxyapatite is the most phase-stable syntetic biomaterial compared to another calcium phospate material. Hydroxyapatite also has high similarity with bone which make it has wide application as syntetic bone graft. Purpose of this research is to study the effect of sintering time towards hydroxyapatite crystal’s purity. Hydroxyapatite made from chemical precursor CaCO3 and (NH4)2HPO4 was synthesized using hydrothermal method on 150oC and 300oC. Synthesized hydroxyapatite was characterized using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive Analysis X-Ray (EDX). The result of characterization showed that highest average intensity on 2θ were: 25.898o, 31.789o, 32.216o, 32.922o, 46.729o, and 49.524o.]"

"Hydroxyapatite (HAP) is a member of the apatite group of minerals, and its chemical formula is Ca10(PO4)6(OH)2. HAP is a Calcium phosphate including hydroxide, and its Ca/P ratio is represented as 1, 67 HAP is being utilized in medical and dental fields including as artificial bones and artificial tooth roots. There are five methods for preparing apatite compounds, but the wet method is most popular, simple and available for mass production. The purpose of this experiment of HAP is to know the technique of synthesizing HAP and to get the data/information about the influence of pH and sintering temperature towards the HAP characteristic. Modification wet method is used in this experiment. The result of DTA, DTA curves of pH 7, pH 9 and pH 11 indicate that the last peak are at 825° C, 835° C and 815° C. The XRD result indicates that almost the entire peak exists are dominant phase and the relative intensity indicate that crystal structure of dominant phase are similar using the Hanawalt method. The physical and mechanical characteristic indicates that at pH 9 with sintering temperature 1100° C, shows the greatest density (3,1327 g/cm3), the smallest porosity (9,2212 % ) and the greatest bending strength (54,9813 MPa) compared with the result at other pH. The conclusion of this experiment are : the synthesis HAP technique "Wet Method" is good enough; the best pH is pH 9 with sintering temperature 1100° C; the connection pattern between pH and character result of HAP sampel is not similar if compared with the connection pattern between sintering temperature and the character result of HAP sample. Sintering process begins at 1000°C, but we cannot know when the sintering temperature ended. The suggestion is doing advance experiment using Rietveld method which needed to know the atomic position in crystal structure of HAP and to know the dominant phase percentage and the minor phase percentage too. We also have to know when sintering process ended with other experiment using sintering temperature of 1200° C and 1300° C.

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Hydroxyapatite ( HAP ) adalah suatu calcium phosphate yang mengandung hydroxyde dengan ratio Ca/P = 1,67 dengan formula kimia Ca10(P04)6(OH)2. Dalam bidang kedokteran dan kedokteran gigi HAP antara lain digunakan sebagai tulang buatan dan akar gigi buatan. Pada saat sekarang, terdapat berbagai metode untuk pembuatan HAP. "Wet Method" merupakan metode yang paling populer, paling mudah dan dapat digunakan untuk produksi masal. Tujuan penelitian adalah dikuasainya teknik proses sintesis dan karakterisasi HAP serta diketahuinya pengaruh perubahaan pH (7, 9 dan 11) dan suhu sintering ( 9000 C, 1000° C dan 1100° C ) terhadap karakterisasi sampel HAP. Metode sintesis HAP yang digunakan adalah "Wet Method" Hasil DTA sampel HAP pada pH 7, pH 9 dan pH 11 menunjukkan adanya puncak terakhir berturut-turut pada suhu 825° C, 835° C dan 815° C. Hasil analisis XRD menunjukkan bahwa hampir semua puncak adalah fasa dominan HAP dan intensitas relative menunjukkan struktur kristal fasa dominan adalah sama. Penentuan fasa dengan menggunakan metode Hanawalt. Posisi atom pada struktur kristal HAP dan prosentase fasa dominan dan .fasa minor tidak dapat ditentukan dengan metode Hanawalt. Hasil uji sifat-sifat fisik dan mekanik sampel HAP pada pH 9 dan suhu sintering 11000 C menunjukkan densitas terbesar (3,1327 g/cm3), porositas terkecil (9,2212 %) dan kekuatan patah terbesar (54,9813 MPa) dibandingkan hasil pengujian pada pH lain. Kesimpulan hasil penelitian adalah bahwa teknik sintesis HAP dengan modifikasi "Wet Method" cukup memuaskan; pH terbaik untuk sintesis HAP adalah pH 9 dengan suhu sintering 11000 C; hubungan pH dengan hasil karakterisasi sampel HAP menunjukkan pola yang tidak sama dengan pola hubungan suhu sintering dengan hasil karakterisasi sampel HAP; proses sintering mulai terjadi pada suhu 1000° C sedangkan akhir proses sintering belum dapat dimonitor. Diperlukan penelitian lanjutan dengan suhu sintering 1200° C dan 1300° C serta penelitian lanjutan dengan metode Rietveld untuk menentukan posisi atom pada struktur kristal HAP dan untuk menentukan prosentase fasa dominan dan fasa minor."

"Chitosan adalah polisakarida alami yang memiliki sifat biokompatibel dan tidak beracun. Kombinasi antara kitosan dan hidroksiapatit akan membentuk nanokomposit yang menyediakan pori-pori untuk migrasi sel sehingga memungkinkan pertumbuhan jaringan dan dapat diaplikasikan sebagai bahan implan tulang. Tujuan dari penelitian ini adalah sintesis dan karakterisasi komposit hidroksiapatit-kitosan melalui in situ yang digunakan oleh iradiasi gelombang mikro dengan variasi waktu. Komposit dibentuk oleh hidroksiapatit dan larutan kitosan 2% melalui in situ kemudian diiradiasi dengan tenaga 270 watt selama 20-60 menit dengan interval 10 menit. Hasil XRD menunjukkan puncak hidroksiapatit dan kitosan. Ukuran kristalit tertinggi ditemukan pada komposit 50 menit dengan nilai 20,87 nm. Spektroskopi FTIR mengidentifikasi kelompok fungsional hidroksiapatit dan kitosan (NH2). Peningkatan waktu iradiasi menyebabkan pengurangan kitosan berdasarkan keberadaan CH dan NH2. Massa tertinggi hadir pada waktu 20 menit yang berarti reduksi massa juga terjadi dengan meningkatnya waktu iradiasi. Hasil SEM dan EDX menunjukkan bahwa hidroksiapatit telah memenuhi matriks kitosan. Kehadiran cluster NH membuktikan bahwa metode iradiasi gelombang mikro dapat digunakan untuk mensintesis nanokomposit hidroksiapatit dan kitosan. Peningkatan waktu iradiasi menyebabkan berkurangnya keberadaan kitosan dan massanya.

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Chitosan is a natural polysaccharide which has biocompatible and non-toxic properties. The combination of chitosan and hydroxyapatite will form nanocomposites which provide pores for cell migration to enable tissue growth and can be applied as bone implant material. The purpose of this study is the synthesis and characterization of hydroxyapatite-chitosan composites through in situ used by microwave irradiation with time variations. Composites are formed by hydroxyapatite and 2% chitosan solution through in situ then irradiated with 270 watts of power for 20-60 minutes at intervals of 10 minutes.

XRD results showed the peak of hydroxyapatite and chitosan. The highest crystallite size was found in the 50 minute composite with a value of 20.87 nm. FTIR spectroscopy identified the hydroxyapatite and chitosan (NH2) functional groups. Increased irradiation time causes reduction of chitosan based on the presence of CH and NH2. The highest mass is present at 20 minutes which means mass reduction also occurs with increasing irradiation time.

SEM and EDX results indicate that the hydroxyapatite meets the chitosan matrix. The presence of NH clusters proves that the microwave irradiation method can be used to synthesize hydroxyapatite and chitosan nanocomposites. Increased irradiation time causes reduced presence of chitosan and its mass."

"Implan biodegradable memiliki nilai lebih karena tidak memiliki efek jangka panjang pasca pemasangan dan tidak memerlukan operasi pengangkatan implan. Kandidat yang cocok untuk implan jenis ini adalah Magnesium (Mg). Dalam aplikasi implan biomedis diperlukan permukaan bahan yang bersifat bioaktif di dalam tubuh, oleh sebab itu biasanya implan berbasis Mg dilapisi permukaannya dengan mineral tulang hidroksiapatit (HA). Dalam penelitian ini, HA tidak digunakan sebagai bahan pelapis melainkan digabungkan dengan Mg dalam bentuk komposit. Metode yang digunakan untuk fabrikasi komposit Mg-HA adalah metalurgi serbuk dan pemadatan dengan Spark Plasma Sintering (SPS). SPS dipilih karena metode ini memiliki kemampuan densifikasi yang tinggi. Penelitian ini dilakukan untuk mengidentifikasi pengaruh waktu milling yaitu 3, 4 dan 5 jam terhadap ukuran partikel dan menganalisa pengaruh komposisi HA yaitu 0, 10, 20, 30 wt% pada sifat korosi dan bioaktivitas komposit yang dihasilkan. Hasil optimasi dengan nilai densitas komposit menunjukkan waktu milling optimum adalah 4 jam dan variasi komposisi HA pada Mg-30HA. Sampel Mg, Mg-10HA, Mg-20HA, dan Mg-30HA dengan waktu milling 4 jam memiliki densitas berturut-turut 1,766; 1,872; 1,832 dan 1.877 g/cm3. Uji XRD menunjukkan kehadiran kedua fasa yaitu Mg dan HA secara terpisah.

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Biodegradable implants are beneficial because they do not have long term effects after installation and do not require post-surgery to remove the implant. Magnesium (Mg) is a suitable candidate for this type of implant. In biomedical implants application, a bioactive surface is required. Therefore, Mg-based implants are usually coated with the bone mineral hydroxyapatite (HA). In this study, HA is not used as coating but mixed with Mg to form composite. The fabrication method used powder metallurgy and compaction method of Spark Plasma Sintering (SPS). SPS was chosen because this method has a high densification capability. This research was conducted to identify the effect of milling time (3, 4, and 5 hours) which resulted in variations in particle size and to analyze the effect of HA composition that is 0, 10, 20, 30 wt% on the resulting composite characteristics. Optimization results with composite density values indicate the optimum milling time is 4 hours and the variation of HA composition in Mg-30HA. Mg sample; Mg-10HA; Mg-20HA and Mg-30HA with a 4-hour milling time have a density of 1.766, respectively; 1,872; 1,832 and 1,877 g/cm3. The results of the XRD showed the presence of the two phases Mg and HA separately."

"[ABSTRAKPenggunaan gelombang mikro dalam beberapa tahun terakhir ini mengalami peningkatan yang sangat pesat seiring berkembangnya teknologi komunikasi dan informasi. Hal ini menimbulkan masalah baru yakni terjadinya polusi gelombang mikro. Untuk mengimbangi dampak negatif polusi interferensi gelombang elektromagnetik, para peneliti mencoba mengembangkan material penyerap gelombang elektromagnetik. Salah satu material yang menjadi kandidat potensial untuk aplikasi penyerap gelombang mikro adalah material berbasis lantanum manganat. Pada penelitian ini dipelajari rekayasa struktur material berbasis lantanum manganat dengan sistem La0,67Ba0,33Mn1-xNix/2Tix/2O3 (x = 0; 0,02; 0,04 dan 0,06). Fasa tunggal senyawa La0.67Ba0.33Mn1-xNix/2Tix/2O3 berhasil dibuat melalui proses pemaduan mekanik menggunakan prekusor-prekusor La2O3, MnCO3, BaCO3, TiO2, dan NiO dengan tingkat kemurnian tinggi. Selanjutnya serbuk hasil pemaduan mekanik menjalani perlakuan pemanasan pada suhu 1200oC selama 10 jam. Material yang telah dipanaskan kemudian dihaluskan kembali selama 20 jam. Hasil refinement pola difraksi sinar X menunjukkan bahwa senyawa La0,67Ba0,33Mn1-xNix/2Tix/2O3 memiliki strukstur kristal monoklinik untuk seluruh variasi x. Kurva histerisis sampel menunjukkan bahwa material ini termasuk magnet lunak. Hasil evaluasi distribusi ukuran partikel material dengan komposisi terbaik yakni La0,67Ba0,33Mn0,06Ni0,03Ti0,03O3 adalah 82,4 nm. Hasil pengujian sifat serapan gelombang mikro pada rentang 8-12,4 GHz menunjukkan material mampu mereduksi gelombang mikro hingga 94 % pada frekuensi 11,4 GHz. Dengan demikian senyawa La0,67Ba0,33Mn1-xNix/2Tix/2O3 dapat dijadikan sebagai material penyerap gelombang mikro.;

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ABSTRACTIn recent years, application of microwaves has been increased along with the development of communication and information technology and highly produces electromagnetic wave interference. To solve this problem, scientist tries to develop a new material that could absorb electromagnetic waves. One of potential candidates for absorbing materials is lanthanum manganese-based system. In this research, La0.67Ba0.33Mn1-xNix/2Tix/2O3 (x = 0, 0.02, 0.04, and 0.06) compound were studied as a microwaves absorber materials. Single phase of La0.67Ba0.33Mn1-xNix/2Tix/2O3 were successfully synthesized by mechanical alloying method. The mixture of all precursors were first mechanically milled for 20 hours and then sintered at a temperature of 1200oC for 10 h in which a fully crystalline material is ensured. The sintered materials were then re-milled for 20 hours to obtain powder-based nanoparticle. X-ray diffraction refinement shows that the samples have monoclinic structure at all x compositions. The hysteresis curve evaluation showed that the sample materials is soft magnetic. The best composition of La0.67Ba0.33Mn1-xNix/2Tix/2O3 with x = 0.06 has been evaluated. The compound has 82.4 nm particle size distributions and it is able to absorb up to 94% microwaves at 11.4 GHz. The study concluded the material of La0.67Ba0.33Mn1-xNix/2Tix/2O3 have a good potential to be a candidate of microwaves absorbing materials.;In recent years, application of microwaves has been increased along with the development of communication and information technology and highly produces electromagnetic wave interference. To solve this problem, scientist tries to develop a new material that could absorb electromagnetic waves. One of potential candidates for absorbing materials is lanthanum manganese-based system. In this research, La0.67Ba0.33Mn1-xNix/2Tix/2O3 (x = 0, 0.02, 0.04, and 0.06) compound were studied as a microwaves absorber materials. Single phase of La0.67Ba0.33Mn1-xNix/2Tix/2O3 were successfully synthesized by mechanical alloying method. The mixture of all precursors were first mechanically milled for 20 hours and then sintered at a temperature of 1200oC for 10 h in which a fully crystalline material is ensured. The sintered materials were then re-milled for 20 hours to obtain powder-based nanoparticle. X-ray diffraction refinement shows that the samples have monoclinic structure at all x compositions. The hysteresis curve evaluation showed that the sample materials is soft magnetic. The best composition of La0.67Ba0.33Mn1-xNix/2Tix/2O3 with x = 0.06 has been evaluated. The compound has 82.4 nm particle size distributions and it is able to absorb up to 94% microwaves at 11.4 GHz. The study concluded the material of La0.67Ba0.33Mn1-xNix/2Tix/2O3 have a good potential to be a candidate of microwaves absorbing materials., In recent years, application of microwaves has been increased along with the development of communication and information technology and highly produces electromagnetic wave interference. To solve this problem, scientist tries to develop a new material that could absorb electromagnetic waves. One of potential candidates for absorbing materials is lanthanum manganese-based system. In this research, La0.67Ba0.33Mn1-xNix/2Tix/2O3 (x = 0, 0.02, 0.04, and 0.06) compound were studied as a microwaves absorber materials. Single phase of La0.67Ba0.33Mn1-xNix/2Tix/2O3 were successfully synthesized by mechanical alloying method. The mixture of all precursors were first mechanically milled for 20 hours and then sintered at a temperature of 1200oC for 10 h in which a fully crystalline material is ensured. The sintered materials were then re-milled for 20 hours to obtain powder-based nanoparticle. X-ray diffraction refinement shows that the samples have monoclinic structure at all x compositions. The hysteresis curve evaluation showed that the sample materials is soft magnetic. The best composition of La0.67Ba0.33Mn1-xNix/2Tix/2O3 with x = 0.06 has been evaluated. The compound has 82.4 nm particle size distributions and it is able to absorb up to 94% microwaves at 11.4 GHz. The study concluded the material of La0.67Ba0.33Mn1-xNix/2Tix/2O3 have a good potential to be a candidate of microwaves absorbing materials.]"

"The IET has organised training courses on microwave measurements since 1983, at which experts have lectured on modern developments. Their lecture notes were first published in book form in 1985 and then again in 1989, and they have proved popular for many years with a readership beyond those who attended the courses.The purpose of this third edition of the lecture notes is to bring the latest techniques in microwave measurements to this wider audience. The book begins with a survey of the theory of current microwave circuits and continues with a description of the techniques for the measurement of power, spectrum, attenuation, circuit parameters, and noise. Various other areas like measurements of antenna characteristics, free fields, modulation and dielectric parameters are also included.The emphasis throughout is on good measurement practice. All the essential theory is given and a previous knowledge of the subject is not assumed."

"Antena Horn merupakan antena yang digunakan dalam komunikasi gelombang mikro (microwave). Antena ini ini dipilih karena mempunyai gain yang tinggi, VSWR yang rendah, lebar pita (bandwidth) yang relatif besar, tidak berat, dan mudah dibuat. Penulisan ini membahas tentang perancangan desain antena horn pada frekuensi 5,5 GHz - 8,5 GHz, yang dapat diaplikasikan, salah satunya sebagai antena pengantara jalur microwave (gelombang mikro) dalam sistem BSS (Base Station Subsystem). Perancangan antena ini dibantu dengan perangkat lunak CST Studio Suite. Hasil fabrikasi adalah sebuah antena horn dengan frekuensi 5,2 GHz - 8,6 GHz. Berdasarkan hasil pengukuran, diperoleh nilai gain sebesar 16,04 dB dan nilai return loss sebesar -33,758 dB pada frekuensi 7 GHz. ,,,,,,Horn antenna is usually used in microwave communication. This antenna is chosen because it has high gain, low VSWR, relatively wide bandwidth, not heavy, and easily fabricated. This thesis provides design of 5.5GHz - 8.5GHz horn antenna model, which can be applied as a microwave link antenna in the Base Station Subsystem (BSS). CST Microwave Studio Software is used for designing the horn antenna. The fabricated antenna operates in the frequency of 5.2 GHz - 8.6 GHz. According to the measurement results, the obtained gain is 16.04 dBi and the return loss is -33.76 dB at frequency of 7 GHz."