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"Zinc Oxide (ZnO) merupakan material yang biasa digunakan sebagai fotodetektor ultraviolet (UV), namun banyaknya defect natural pada ZnO menyebabkan tingginya dark current sehingga dapat menghambar performanya. ZnO NRs menghasilkan photocurrent paling tinggi saat diberikan cahaya UV dan sangat rendah saat diberikan cahaya cyan dan red, sehingga hanya sesuai sebagai fotodetektor UV. Oleh sebab itu, pada penelitian ini dilakukan dekorasi material TMD seperti MoS2, WS2 dan MoSe2 Quantum Dots (QDs) yang digunakan untuk mengurangi surface defect ZnO. MoS2, WS2 dan MoSe2 QDs disintesis menggunakan metode Pulsed Laser Ablation (PLA) kemudian dilapisi ke permukaan ZnO nanorods (NRs) yang disintesis menggunakan metode hydrothermal. Heterostructure ZnO/TMD menunjukkan penurunan dark current hingga lebih dari 82% untuk ZnO/MoS2 dan meningkatkan photocurrent hingga 127% untuk ZnO/WS2 di bawah cahaya UV pada tegangan 1 Volt. ZnO/MoS2 dapat meningkatkan sensitifitas 13 kali dan ZnO/WS2 dan ZnO/MoSe2 dapat meningkatkan sensitifitas 3-4 kali. Area yang sangat aktif dan tidak stabil pada tepi Mo, S maupun Se sangat mudah bereaksi dengan oxygen di udara sehingga dapat berkontribusi penuh dengan menurunnya dark current.

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Zinc oxide (ZnO) is extensively used as an active material of ultraviolet (UV) detector, but the high dark current that comes from intrinsic defects limits its performance. ZnO nanorods (NRs) exhibit highest photocurrent under UV lights while lower photocurrent when exposed to cyan and red lights, so ZnO may only suatable as UV photodetector. Here, a new approach is proposed to reduce surface defects by decorating with MoS2, WS2 and MoSe2 quantum dots (QDs). MoS2, WS2 and MoSe2 QDs were fabricated by the pulsed laser ablation method and subsequently coated on the surface of hydrothermally grown ZnO nanorods (NRs). ZnO/TMD heterostucture shows a significant reduction in dark current until 82% for ZnO/MoS2 and also increases photocurrent more than 127% for ZnO/WS2 under 1V bias voltage. The sensitivities of ZnO/MoS2 are increased by more than 13 times, while ZnO/WS2 and ZnO/MoSe2 are increased by 3-4 times. The abundant active sites Mo-edges, S-edges, and Se-edges seem to be imperative in trapping dark current electrons, reducing recombination centers when exposed to UV light, and contributing to the adsorption and desorption process of O2 molecules."

"Nanopartikel ZnO merupakan bahan logam oksida yang memiliki kemampuan fotokatalis. Dekorasi ZnO dengan nanopartikel plasmonik diharapkan dapat menimbulkan LSPR yang meningkatkan aktivitas fotokatalitik. Pada penelitian ini emas (Au) dan perak (Ag) dipilih untuk memodifikasi ZnO sebagai material yang memiliki efek plasmonik yang dapat peningkatan medan elektromagnetik yang kuat di dekat permukaan nanopartikel. Peningkatan ini menawarkan peluang untuk meningkatkan penyerapan cahaya dan meningkatkan pemisahan muatan dalam sistem fotokatalitik. Pada penelitian ini sintesis nanomaterial tersebut dilakukan melalui RLAL. Teknik laser ablasi yang digunakan memiliki keistimewaan berupa proses yang biocompatible dengan meminimalkan penggunaan bahan kimia, namun parameter sintesis tetap dapat dikontrol dengan baik. Nanopartikel yang dihasilkan lebih murni dan memiliki permukaan yang bersih. Parameter sintesis pada penelitian ini, energi laser divariasi untuk masing-masing jenis material plasmonik, sehingga mendapatkan energi laser maksimum berdasarkan nilai uji fotokatalitik tertinggi. Karakteristik nanokomposit yang terbentuk diuji dengan UV-Vis dan TEM. Hasil penelitian menunjukkan, energi laser meningkatkan optical density ZnO dan energi band gap. Nanopartikel ZnO hasil sintesis memiliki puncak absorbansi pada spektrum UV dengan energi bandgap 3,14 – 3,3 eV dengan ukuran partikel 45 ± 15 nm, nanokomposit ZnO-Au memiliki energi bandgap 3,0 – 3,3 eV dengan ukuran partikel 42 ± 16 nm (ZnO) dan 9 ± 13 nm (Au), dan nanokomposit ZnO-Ag memiliki energi bandgap 3,26 – 3,3 eV dengan ukuran partikel 43 ± 14 nm (ZnO) dan 8 ± 3 nm (Ag). Nanokomposit ZnO-Au memiliki keamampuan degradasi RhB pada cahaya tampak sebesar 72,39% dan sedangkan ZnO-Ag 67,30 %.

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Zinc oxide (ZnO) nanoparticles are a metal oxide material with photocatalytic properties. Decoration of ZnO with plasmonic nanoparticles is expected to induce LSPR, which enhances photocatalytic activity. In this study, gold (Au) and silver (Ag) were chosen to modify ZnO as materials that have a plasmonic effect that can increase the strong electromagnetic field near the nanoparticle surface. This enhancement offers opportunities to improve light absorption and enhance charge separation in the photocatalytic system. In this study, the synthesis of these nanomaterials was carried out using RLA. The laser ablation technique used has the advantage of being a biocompatible process by minimizing the use of chemicals, but the synthesis parameters can still be well controlled. The resulting nanoparticles are purer and have a clean surface. The synthesis parameters in this study, laser energy was varied for each type of plasmonic material, to obtain the maximum laser energy based on the highest photocatalytic test value. The characteristics of the formed nanocomposites were tested with UV-Vis and TEM. The results showed that laser energy increases the optical density of ZnO and the band gap energy. The synthesized ZnO nanoparticles have an absorption peak in the UV spectrum with a band gap energy of 3.14 – 3.3 eV with a particle size of 45 ± 15 nm, ZnO-Au nanocomposites have a band gap energy of 3.0 – 3.3 eV with a particle size of 42 ± 16 nm (ZnO) and 9 ± 13 nm (Au), and ZnO-Ag nanocomposites have a band gap energy of 3.26 – 3.3 eV with a particle size of 43 ± 14 nm (ZnO) and 8 ± 3 nm (Au). ZnO-Au nanocomposites could degrade RhB under visible light by 72.39%, while ZnO-Ag is 67.30%."

"ABSTRAKSaat ini teknologi nuklir berkembang dengan baik di Indonesia dan pemanfaatannya baik di bidang kesehatan, pertanian, peternakan, industri dan energi digunakan sepenuhnya untuk kesejahteraan seluruh masyarakat Indonesia. Dalam pengembangan dan pemanfaatan teknologi nuklir tentu harus mempertimbangkan dan meminimalisir efek bahaya dari radiasi nuklir, baik untuk pekerja yang berada dilingkungan instalasi nuklir maupun bahaya kontaminasi lingkungan disekitar instalasi nuklir. Untuk itu kegiatan pemantauan, pendeteksian dan pengukuran radiasi mutlak diperlukan. Umumnya kegiatan pemantauan, pendeteksian dan pengukuran radiasi dilakukan dengan perangkat deteksi nuklir. Pada penelitian kali ini dilakukan metode alternatif pengukuran, analisis dan identifikasi unsur radioaktif dengan teknik laser induced plasma spectroscopy LIPS . Penggunaan teknologi LIPS dipilih karena LIPS adalah suatu teknik analisis sampel secara in situ, kualitatif dan kuantitatif yang cepat, dan hampir tanpa preparasi sampel. Analisis dan identifikasi unsur radiaoaktif dilakukan dengan menembakkan laser pulsa NdYAG Q-Switch 355 nm, 10 Hz, durasi pulsa 5.5 ns, f = 100 mm, dengan variasi energi 5.5 mJ - 140 mJ dan dengan variasi tekanan udara 4 Torr ndash; 1 atm pada sampel material radioaktif alamiah atau Naturally Occurring Radioactive Material NORM dengan metoda ablasi laser yang dilanjutkan dengan metoda spectral plasma analisis. Berdasarkan penelitian yang telah dilakukan, secara kualitatif teknik LIPS mampu mengidentifikasi adanya unsur radioaktif Uranium U dan Thorium Th yang terdapat pada sampel uji dengan energi laser optimum sebesar 107 mJ dan secara kuantitatif didapatkan nilai prediksi konsentrasi unsur Uranium sebesar 155 ppm dengan persentase error 11.3 dan nilai batas deteksi sebesar 7.89 ppm, nilai prediksi konsentrasi unsur Thorium sebesar 124 ppm dengan persentase error 8 dan nilai batas deteksi sebesar 12.4 ppm. Dengan kata lain teknik LIPS secara inheren sangat cocok dan sangat memungkinkan digunakan sebagai teknik pengukuran, analisis dan identifikasi keberadaan unsur radioaktif.

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ABSTRACTNuclear technology is currently well developed in Indonesia and its use in the field of health, agriculture, industry and energy is completely used for the welfare of all the people of Indonesia. In the development and utilization of nuclear technology should certainly consider and minimize the effects of nuclear radiation hazards, both for the workers who are in the environment of nuclear installations and the danger of contamination of the environment around nuclear installations. Therefore monitoring activity, detection and measurement of radiation is absolutely necessary. Generally the monitoring activity, detection and measurement of radiation carried by the nuclear detection devices. In this study, alternative methods of measurement, analysis and identification of radioactive elements is carried out by using laser induced plasma spectroscopy LIPS . The use of LIPS technology is selected since LIPS is a technique in situ sample analysis, qualitative and quantitative fast, and almost no sample preparation. Analysis and identification of the radioactive element is carried out by firing laser pulses NdYAG Q Switch 355 nm, 10 Hz, pulse duration of 5.5 ns, f 100 mm, with a variation of the energy 5.5 mJ 140 mJ and with variations in air pressure 4 Torr 1 atm in a sample of Naturally Occurring Radioactive Material NORM with laser ablation method, followed by plasma spectral analysis method. Based on the research that has been done, LIPS technique is qualitatively able to identify the presence of radioactive elements, i.e. Uranium U and thorium Th contained in the test sample with a laser energy optimum of 107 mJ and quantitatively obtained predictive value of elemental concentrations of Uranium of 155 ppm along with 11.3 of percentage error and 7.89 ppm of detection limit value, also the predictive value of the elemental concentration of thorum of 124 ppm along with 8 of percentage error and 12.4 ppm of detection limit value. In other words, LIPS technique is inherently very suitable and it is possible to use as a measurement technique, analysis and identification of the presence of radioactive materials."

"Pada penelitian ini telah dilakukan sintesis ZnO nanorods (NR) 4 jam dan ZnO nanotubes (NT) dengan variasi waktu self-etching 18 jam dan 22 jam dan diapikasikan sebagai devais detektor UV 365 nm. Nanomaterial ini telah disintesis menggunakan metode ultrasonic spray pyrolysis (USP) dan hydrothermal. ZnO NT telah berhasil disintesis melalui proses self-etching ZnO NR yang tidak mengalami perubahan fasa kristal, parameter kisi maupun energi band gap. Namun demikian ZnO NT yang dihasilkan memiliki lebih banyak cacat kristal yang diindikasikan dengan kurva absorbansi optik yang lebih lebar pada daerah cahaya tampak. Hal ini menyebabkan penurunan photocurrent yang lebih tinggi daripada penuruan dark current , yang menyebabkan penurunan kinerja fotodetektor UV. Nilai sensitivitas ZnO NR menurun dari 43,74% menjadi 29,20% dan 30,80% pada sampel ZnO NT 18 jam dan 22 jam. Demikian pula nilai responsivitas menurun dari 5,83 A/W menjadi 3,09 A/W dan 4,06 A/W dan nilai detektivitas menurun dari 1,20×106 Jones menjadi 0,71×106 Jones dan 0,84×106 Jones.

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In this study, the synthesis of ZnO nanorods (NR) and ZnO nanotubes (NT) with variations in self-etching time of 18 h and 22 h was carried out and applied as a UV detector device. This nanomaterial has been synthesized using ultrasonic spray pyrolysis (USP) and hydrothermal methods. ZnO NT has been successfully synthesized through the self-etching process of ZnO NR which does not change the crystal phase, lattice parameters or band gap energy. However, the resulting ZnO NT has more crystal defects indicated by a wider optical absorbance curve in the visible light region. This results in a higher photocurrent IL than an dark current ID, leading to a decrease in the performance of the UV photodetector. The sensitivity of ZnO NR decreased from 43.74% to 29.20% and 30.80% in samples of ZnO NT 18 h and 22 h. Likewise, the responsivity value decreased from 5.83 A/W to 3.09 A/W and 4.06 A/W and the detectivity value decreased from 1.20×106 Jones to 0.71×106 Jones and 0.84×106. Jones."

"ABSTRACTLaser induced thin film production (LITFP) technique was employed for making plumbum (Pb) thin film by nitrogen laser deposition in miniature scale. The energy of nitrogen laser operated at 12.5 kv, 90 torr was 3.5 mj with 5 ns pulse duration, thus producing peak power at around 0.7 MW. Pb plasma of 1 cm diameter was generated in each laser bombardment, producing thin film above the glass substrate. The thin film characteristics were measured by means of their thickness and surface morphology using scanning electron microscope (SEM). It was proved that there was a linear relationship between the number of laser shots and film thickness."

"The purpose of this reserach is to find out the influence of laser shooting to the ovaries stem of eye,ablation of crab's eye to the level of egg's maruty,the diameter of eggs and the number of eggs scylla serrata....."

"ABSTRACT

Probing of the atmospheric parameters have been done by many scientists since a century ago up to present with various techniques. A simple system of laser radar without using any collimated beam but a reflected mirror as transmitter and a small cassegranian type (10.5 an in diameter) telescope as receiving was constructed to investigate the relative Mie backscattering coefficient by utilizing a nitrogen laser as a light source in the range of measurement bellow 1 Km. The backscattered light received by the receiving telescope is converted into electric current by photomultiplier and is shown and known as "A scope" display on an oscilloscope. SNR of the signal from photomultiplier was increased by using a boxcar integrator and its output could be recorded with XY recorder."

"Nanopartikel emas (AuNPs) merupakan suatu bahan yang mulai marak digunakan dalam bioimaging. AuNPs yang digunakan dalam bioimaging umumnya disintesis menggunakan metode kimiawi. Salah satu teknik pencitraan yang memakai AuNPs sebagai medium adalah Two photon microscopy. Teknik ini memanfaatkan eksitasi two photon pada AuNPs untuk memberikan label pada sampel-sampel biologis. Pada penelitian ini, telah disintesis AuNPs menggunakan metode ablasi laser menggunakan laser Nd:YAG dengan panjang gelombang 1064 nm selama 5 menit. Tiga jenis pelarut (aqueous, polyvinyl alcohol dan polyethylene glycol) digunakan untuk memodifikasi diameter AuNPs. Masing-masing AuNPs ini menunjukkan puncak absorbsi yang berbeda pada spektrometri UV-Vis. Spektrum ini kemudian dibandingkan dengan sebuah alat simulasi pada MATLAB. Didapatkan besar diameter AuNPs untuk masing-masing parameter adalah 16,2 nm, 16,7 nm, dan 15,9 nm secara berurutan. Telah dibuat pula setup optik untuk melakukan uji eksitasi two photon (TPE) pada AuNPs memvariasikan daya dari laser femtosecond. Didapatkan bahwa TPE terjadi pada rentang panjang gelombang ~490 sampai ~500 nm dengan daya laser sebear 1,2 W sampai 1,8 W.

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Gold nanoparticles (AuNPs) is a material that has been gaining attraction in bioimaging. AuNPs that used in bioimaging usually shynthetized using chemmicals method. An example of imaging techniques that use AuNPs as medium is Two photon microscopy. This technique use two photon excitation on AuNPs to dye or labels biological samples. Ini this experiment, AuNPs have been successfully fabricated using laser ablation method by Nd:YAG lser with 1064 nm wavelength for 5 minute. Three different solution (aqueous, polyvinyl alcohol and polyethylene glycol) was applied to modify AuNPs diameter. Each of these AuNPs was observed by mean UV-Vis spectroscopy exhibit different absorption peak. This spectrum then was compared to simulation tool on MATLAB. The measured AuNPs’ diameters was 16,2 nm, 16,7 nm, dan 15,9 nm repectively. An optical setup for two photon excitation (TPE) experiment on AuNPs has also been made by varying the power of femtosecond laser. TPE was detected at ~490 to ~500 nm range with laser power about 1,2 W to 1,8 W."

"ABSTRACTThe frequency dobled Rd: YAG laser (532 nm/10ns, 15mj/pulse) uses a pulsed, frequency dobled; which provides a monochromatic, energy source with extremely high peak power and to has capability to develop of latent fingerprint on various surface. In the porous surfaces, this laser to has superiority, the compared with the development another methods, like powder and chemical method in latent fingerprint development. The high peak power of the laser causes Palmar sweat: contain a variety compounds, among them amino acids, oils, enzymes, vitamins and other chemicals with in the print to fluoresce. Some latent fingerprints will fluoresce in their natural state during exposure to this laser energy. The natural state fluorescing prints make can be documented and recording by high-resolution TV cameras and monitor for maximum sensitivity. The next step, the compare latent fingerprints products with visible impression by comparable instruments, see patterns of the friction ridges and be found same amount of their galton detail. "

"Kopling antara amplifier permukaan miring dan fiber taper lens-ended diselidiki secara teori. Penelitian teori didasarkan pada model gelombang bidang tiga dimensi yang dihitung melalui pergeseran fasa akibat permukaan iring. Kopling diselidiki berkenaan dengan parameter-parameter berkas dari pandu gelombang amplifier lens-ended, dan juga berkenaan dengan posisi fiber. Terjadinya rugi-rugi kopling karena permukaan miring dan karena variasi dari uji lens yang terbaik, rugi untuk permukaan miring 10° ditemukan lebih kecil dari 0.5 dB dibandingkan amplifier permukaan normal.

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The coupling between angled-facet amplifiers and tapered lens-ended fibers is investigated theoretically. The theoretical investigation is based on a three-dimensional plane wave model which accounts for the phase differences introduced by the angled facets. The coupling is investigated with respect to the beam parameters of the amplifier wave guids and the tapered lens-ended fiber, and also with respect to the fiber position. For optimized lens radii the excess loss for 0l0° facet angle is found to be less than 0.5 dB compared to a normal facet amplifier."