Sheet Electron Research Articles

Analysis of the Effectiveness of PBL-Oriented Interactive Electronic Student Activity Sheets Development on the Material of Factors Affecting Chemical Equilibrium to Improve Students Science Literacy Skills

The science literacy skills of Indonesian students are still low based on the results of PISA 2022. Chemical equilibrium material is very important, and understanding chemical equilibrium is a prerequisite for understanding subsequent materials. One of the efforts to improve understanding of chemical equilibrium material is applying a student-centred learning model, the PBL model. PBL can also improve students' science literacy skills. Thus, research was conducted to develop PBL-oriented interactive electronic student activity sheets on chemical equilibrium material to improve students' science literacy skills. This research aims to describe the effectiveness of interactive E-LAPD as a learning media for improving students' science literacy skills. Research and development (Research and Development) is the type of research used. The research design used in this research is the 4-D model development research design according to Thiagarajan's 4-D model, which consists of the define, design, develop, and disseminate stages. The instrument used in this research is a pretest and posttest sheet of science literacy skills to measure students' science literacy skills. This research used a limited trial with a one-group pretest-posttest research design. The limited trial was conducted at SMAN 1 Kedamean with 36 class XI MIPA 3 students. The effectiveness results analyzed using the paired sample t-test obtained a p-value of 0.000, which indicates that the posttest value after learning using interactive E-LAPD is greater than the pretest value before learning using interactive E-LAPD. Thus, PBL-oriented Interactive E-LAPD can be said to improve students' science literacy skills.

Prediction of s^{±}-Wave Superconductivity Enhanced by Electronic Doping in Trilayer Nickelates La_{4}Ni_{3}O_{10} under Pressure.

Motivated by the recently reported signatures of superconductivity in trilayer La_{4}Ni_{3}O_{10} under pressure, we comprehensively study this system using abinitio and random-phase approximation techniques. Without electronic interactions, the Ni d_{3z^{2}-r^{2}} orbitals show a bonding-antibonding and nonbonding splitting behavior via the O p_{z} orbitals inducing a "trimer" lattice in La_{4}Ni_{3}O_{10}, analogous to the dimers of La_{3}Ni_{2}O_{7}. The Fermi surface consists of three electron sheets with mixed e_{g} orbitals, and a hole and an electron pocket made up of the d_{3z^{2}-r^{2}} orbital, suggesting a Ni two-orbital minimum model. In addition, we find that superconducting pairing is induced in the s^{±}-wave channel due to partial nesting between the M=(π,π) centered pockets and portions of the Fermi surface centered at the Γ=(0,0) point. With changing electronic density n, the s^{±} instability remains leading and its pairing strength shows a domelike behavior with a maximum around n=4.2 (∼6.7% electron doping). The superconducting instability disappears at the same electronic density as that in the new 1313 stacking La_{3}Ni_{2}O_{7}, correlated with the vanishing of the hole pocket that arises from the trilayer sublattice, suggesting that the high-T_{c} superconductivity of La_{3}Ni_{2}O_{7} does not originate from a trilayer and monolayer structure. Furthermore, we confirm the experimentally proposed spin state in La_{4}Ni_{3}O_{10} with an in-plane (π, π) order and antiferromagnetic coupling between the top and bottom Ni layers, and spin zero in the middle layer.

Reversible Carrier Concentration Control on Ultra-Thin in2O3 By Viologen Molecules Charge Transfer Method

Ultra-thin Oxide semiconductor fabricated by atomic layer deposition (ALD) is one of the promising candidates, due to their ultra-thin thickness and being highly compatible with the silicon process.[1] However, further tuning the oxide semiconductor's carrier concentration is still an interesting issue. Although annealing is a widely used way, the increase in thermal budget is unwilling to be met. To adjust the carrier concentration without increasing the thermal budget, viologen molecule, a strongly n-type dopant which have been successfully applied to different material systems including 2D,[2] CNT,[3] ultra-thin Ⅲ-Ⅴ,[4] has been used in the In2O3 transistor(as shown in Figure 1a). After viologen treatment, the viologen dopants increased the carrier concentration and caused a difference of n 2D, which is 2 × 1012 cm-2 of 2 nm thickness in In2O3, without degrading the mobility under the same overdrive voltage. The In2O3 transistor achieves an electron sheet density of 6.8 × 1012 cm−2. To further expand the function, viologen dopants are modified by hydroxy group. With hydroxy group modifying, the viologen dopants can be removed by acetone and be re-treated back on the In2O3 again. The reversible cycle of viologen treatment can be repeated multiple times without harming the In2O3 device (as shown in Figure 1b). Precise control of the threshold voltage allows for fine-tuning of the transistor between depletion mode and enhancement mode. Based on this, a depletion load inverter has been demonstrated. This result shows that the viologen dopants and In2O3 have the potential to be further integrated with other low dimensional materials in BEOL without raising the thermal budget while tuning the carrier concentrations. Figure 1. a) Schematic representation of the structure of a In2O3 bottom-gate transistor and the viologen charge transfer process. b) The transfer characteristics of In2O3 transistors repeatedly treated and removed of OHV for four cycles. References (1) Si, M.; Lin, Z.; Chen, Z.; Sun, X.; Wang, H.; Ye, P. D. Scaled Indium Oxide Transistors Fabricated Using Atomic Layer Deposition. Nat. Electron. 2022, 5 (3), 164-170. DOI: 10.1038/s41928-022-00718-w.(2) Kiriya, D.; Tosun, M.; Zhao, P.; Kang, J. S.; Javey, A. Air-Stable Surface Charge Transfer Doping of MoS2 by Benzyl Viologen. J. Am. Chem. Soc. 2014, 136 (22), 7853-7856. DOI: 10.1021/ja5033327.(3)Kim, S. M.; Jang, J. H.; Kim, K. K.; Park, H. K.; Bae, J. J.; Yu, W. J.; Lee, I. H.; Kim, G.; Loc, D. D.; Kim, U. J.; Lee, E.-H.; Shin, H.-J.; Choi, J.-Y.; Lee, Y. H. Reduction-Controlled Viologen in Bisolvent as an Environmentally Stable n-Type Dopant for Carbon Nanotubes. J. Am. Chem. Soc. 2009, 131 (1), 327-331. DOI: 10.1021/ja807480g.(4) Takei, K.; Kapadia, R.; Li, Y.; Plis, E.; Krishna, S.; Javey, A. Surface Charge Transfer Doping of III–V Nanostructures. J. Phys. Chem. C 2013, 117 (34), 17845-17849. Figure 1

Development of E-Worksheet Inquiry-Flipped Classroom on Chemical Equilibrium Material To Improve Students' Analytical Thinking Skills

One of the skills that students must have in the 21st century is analytical thinking skills. Learning media that can support this is needed to facilitate learning and practice analytical thinking skills. One learning media that can be used is an electronic student activity sheet (e-worksheet). This research aims to produce a product in the form of an e-worksheet suitable for use to improve students' analytical thinking skills on chemical equilibrium material. The feasibility of the e-worksheet is reviewed on its validity, effectiveness, and practicality. The method used is the research and development of 4D models consisting of definition, design, development, and deployment. This research was limited to the development stage by conducting a limited trial on students in grades XI-8 of SMAN 7 Surabaya who had studied chemical equilibrium material. The data collection technique of this research uses questionnaire, observation, and test methods. The research instruments used in this study include study sheets, validation sheets, student response questionnaire sheets, observation sheets, and test sheets. This study was analyzed using the N-gain test and the Wilcoxon test. The results of the validation of the e-worksheet from the aspects of content validity and construct validity obtained a mode of 4 so that it can be declared very valid for use. The results of the student response questionnaire reached an average of 98% positive responses in the very practical category. The results of the analysis of pretest and post-test data were obtained to improve analytical thinking skills, which was shown by 80% of students receiving an N-gain score of ≥ 0.7 with a high category and based on the Wilcoxon test, a P-Value value of 0.000 (< 0.05) was obtained which stated that there was a significant difference between the pretest and posttest scores Learners. From the results of the N-Gain analysis and the Wilcoxon Test, the e-worksheet was declared effective. It was concluded that the flipped classroom inquiry e-worksheet on chemical equilibrium material is suitable for training students' analytical thinking skills.

Potential of Cosmos caudatus Kunth. extract as natural food sanitiser

Bacterial growth in food sources after harvesting and during food manufacturing has emerged as a major agricultural concern. Currently, several chemical preservatives have been added to foods to prevent or inhibit bacterial growth. These phenomena, however, become a concern when consumers begin to demand the safety of the food they consume, thus resulting in a search for natural plant extracts as an alternative. The antimicrobial activity of Cosmos caudatus leaf extract against six food pathogens was thus investigated in the present work. The disc-diffusion test, the minimum inhibitory concentration (MIC), and the minimum bactericidal concentration (MBC) tests were used to determine the antibacterial potential. Time-kill kinetics were used to determine their killing endpoints at various incubation times. Thereafter, Bacillus cereus was selected as a representative bacterium to be viewed under the light sheet electron microscope (LSEM) to observe the morphological changes. For the application as a sanitiser, different concentrations of C. caudatus extract were applied to chicken meat and oyster mushroom to determine bacterial reduction and sensory acceptability. The toxicity test using brine shrimp lethality assay was also performed to determine the toxicity level of C. caudatus extract. Results showed that C. caudatus extract contain five major peaks of flavonoids. In the antibacterial test, all tested pathogens were inhibited, with B. cereus being the most susceptible, with a significant reduction time of more than 3 log10 at 3.125 mg/mL. Under LSEM, the population of B. cereus was reduced, and the shape was wrinkled. In the application, C. caudatus extract at 0.05% for 5 min treatment time was chosen as the best formulation, whereas the brine shrimp tests showed that C. caudatus extract was safe for human consumption (LC50: 3.54 mg/mL). In conclusion, C. caudatus extract could have the potential to be further explored as a natural food sanitiser.

Achieving semi-metallic conduction in Al-rich AlGaN: Evidence of Mott transition

The development of high performance wide-bandgap AlGaN channel transistors with high current densities and reduced Ohmic losses necessitates extremely highly doped, high Al content AlGaN epilayers for regrown source/drain contact regions. In this work, we demonstrate the achievement of semi-metallic conductivity in silicon (Si) doped N-polar Al0.6Ga0.4N grown on C-face 4H-SiC substrates by molecular beam epitaxy. Under optimized conditions, the AlGaN epilayer shows smooth surface morphology and a narrow photoluminescence spectral linewidth, without the presence of any secondary peaks. A favorable growth window is identified wherein the free electron concentration reaches as high as ∼1.8 × 1020 cm−3 as obtained from Hall measurements, with a high mobility of 34 cm2/V·s, leading to a room temperature resistivity of only 1 mΩ·cm. Temperature-dependent Hall measurements show that the electron concentration, mobility, and sheet resistance do not depend on temperature, clearly indicating dopant Mott transition to a semi-metallic state, wherein the activation energy (Ea) falls to 0 meV at this high value of Si doping for the AlGaN films. This achievement of semi-metallic conductivity in Si doped N-polar high Al content AlGaN is instrumental for advancing ultrawide bandgap electronic and optoelectronic devices.

Generation of attosecond gigawatt soft x-ray pulses through coherent Thomson backscattering.

Collision between relativistic electron sheets and counterpropagating laser pulses is recognized as a promising way to produce intense attosecond x rays through coherent Thomson backscattering (TBS). In a double-layer scheme, the electrons in an ultrathin solid foil are first pushed out by an intense laser driver and then interact with the laser reflected off a second foil to form a high-density relativistic electron sheet with vanishing transverse momentum. However, the repulsion between these concentrated electrons can increase the thickness of the layer, reducing both its density and subsequently the coherent TBS. Here, we present a systematic study on the evolution of the flying electron layer and find that its resulting thickness is determined by the interplay between the intrinsic space-charge expansion and the velocity compression induced by the drive laser. How the laser driver, the target areal density, the reflector, and the collision laser intensity affect the properties of the produced x rays is explored. Multidimensional particle-in-cell simulations indicate that employing this scheme in the nonlinear regime has the potential to stably produce soft x rays with several gigawatt peak power in hundreds of terawatt ultrafast laser facilities. The pulse duration can be tuned to tens of attoseconds. This compact and intense attosecond x-ray source may have broad applications in attosecond science.

Large transverse thermoelectric effect induced by the mixed-dimensionality of Fermi surfaces

Transverse thermoelectric effect, the conversion of longitudinal heat current into transverse electric current, or vice versa, offers a promising energy harvesting technology. Materials with axis-dependent conduction polarity, known as p × n-type conductors or goniopolar materials, are potential candidate, because the non-zero transverse elements of thermopower tensor appear under rotational operation, though the availability is highly limited. Here, we report that a ternary metal LaPt2B with unique crystal structure exhibits axis-dependent thermopower polarity, which is driven by mixed-dimensional Fermi surfaces consisting of quasi-one-dimensional hole sheet with out-of-plane velocity and quasi-two-dimensional electron sheets with in-plane velocity. The ideal mixed-dimensional conductor LaPt2B exhibits an extremely large transverse Peltier conductivity up to ∣αyx∣ = 130 A K−1 m−1, and its transverse thermoelectric performance surpasses those of topological magnets utilizing the anomalous Nernst effect. These results thus manifest the mixed-dimensionality as a key property for efficient transverse thermoelectric conversion.

The development of W waveband diffraction radiation oscillator

This study presents the development of a continuous wave diffraction radiation oscillator utilizing a sheet electron beam. The oscillator comprises a slow-wave system formed by double-comb gratings, an open resonant cavity consisting of a spherically curved mirror and a cylindrically curved mirror, and a sheet electron beam generated by a diode gun. A permanent magnetic focusing system stabilizes the transmission of the sheet electron beam within the slow-wave system. Through a combination of mechanical and electronic tuning, the oscillator generates stable signal output in the TEM00q mode. The oscillator's frequency tuning range spans from 87 to 97 GHz, achieving a maximum output power of 13.5 W.

Impact of composition and thickness of step-graded AlGaN barrier in AlGaN/GaN heterostructures

We propose an optimization method to change the Al component and the thickness of step-graded AlGaN barrier to achieve better electrical performance of the device. Based on the polarization effect, we find that a second potential well occurs while increasing the Al fraction and thickness of the upper AlGaN layer, which contributes to better drain current performance in the simulations. The wafers with different AlGaN barriers were grown to compare their surface morphology and electrical properties. The surface roughness of the wafer is related to the lattice constant of the upper AlGaN layer. According to the Hall and TLM measurements, the electron sheet density and electron mobility of the 20 nm-Al0.35Ga0.65N/10 nm-Al0.25Ga0.75N barrier sample are 1593 cm2/Vs and 1.17 × 1013 cm−2 respectively, resulting in a high spacing current of 61.45 mA. Moreover, the maximum drain current density of this barrier device is 589.02 mA/mm under the I–V characteristics, 1.37 times as much as that of the 20 nm-Al0.25Ga0.75N barrier. The higher gate barrier height of Al0.35Ga0.65N reduces the gate leakage current.

Optical and Electrical Properties of AlxGa1-xN/GaN Epilayers Modulated by Aluminum Content.

AlGaN-based LEDs are promising for many applications in deep ultraviolet fields, especially for water-purification projects, air sterilization, fluorescence sensing, etc. However, in order to realize these potentials, it is critical to understand the factors that influence the optical and electrical properties of the device. In this work, AlxGa1-xN (x = 0.24, 0.34, 0.47) epilayers grown on c-plane patterned sapphire substrate with GaN template by the metal organic chemical vapor deposition (MOCVD). It is demonstrated that the increase of the aluminum content leads to the deterioration of the surface morphology and crystal quality of the AlGaN epitaxial layer. The dislocation densities of AlxGa1-xN epilayers were determined from symmetric and asymmetric planes of the ω-scan rocking curve and the minimum value is 1.01 × 109 cm-2. The (101¯5) plane reciprocal space mapping was employed to measure the in-plane strain of the AlxGa1-xN layers grown on GaN. The surface barrier heights of the AlxGa1-xN samples derived from XPS are 1.57, 1.65, and 1.75 eV, respectively. The results of the bandgap obtained by PL spectroscopy are in good accordance with those of XRD. The Hall mobility and sheet electron concentration of the samples are successfully determined by preparing simple indium sphere electrodes.

Biomechanical comparison of composite and cadaveric humeri models in experiments on operated humeral shaft fractures

A study was undertaken to determine how well contacting fracture fragments of composite bone replicated the behavior of fracture fragments in real bone. Ten composite and ten real humeral diaphyses were transected and reconstructed with limited-contact dynamic-compression plates. Two screws were placed on each side of the transection site and a calibrated electronic sensor sheet was placed between the imitated fracture fragments. After insertion of the distal screws, pressure measurements were made during insertion of the first proximal screw in compression mode, during insertion of the second screw in compression mode after loosening the first screw, and finally after retightening the first screw. The process was repeated after bending the plate. The contact area, the net compression force and the average compressive stress were computed and statistically compared. The composite bone and cadaveric bone differed in contact area and compressive stress but not in net compressive force. Plate bending did not produce a significant difference between composite and cadaveric bone. The results indicate that composite bone does not reproduce all the local fracture fragment conditions so that hardware testing in composite bone should proceed carefully. A gap between fracture fragments as is often used in comminuted fracture tests may remain as the most appropriate situation for fracture hardware testing.

Diffusion Control on the Van der Waals Surface of Monolayers for Uniform Bi‐Layer MoS2 Growth

Abstract2D MoS2 has gained attention for the post‐silicon material owing to its atomically thin nature and dangling bond‐free surface. The bi‐layer MoS2 is considered a promising material for electronic devices due to its better electrical properties than monolayer MoS2. However, the uniform growth of bi‐layer MoS2 is still challenging. Herein, the uniform growth of bi‐layer MoS2 is demonstrated using gas‐phase alkali metal‐assisted metal–organic chemical vapor deposition (GAA‐MOCVD). Thanks to enhanced metal reactant diffusion length in GAA‐MOCVD, the uniform growth of bi‐layer MoS2 film is achieved even at fast nucleation kinetics for a shorter growth time compared to previously reported MOCVD. The bi‐layer MoS2 field‐effect transistors (FETs) show superior electrical properties such as sheet conductance and electron mobility than monolayer MoS2 FETs. The electron mobility of bi‐layer MoS2 FETs with bismuth contacts reaches a maximum of 92.35 cm2 V−1 s−1. Using the partially grown epitaxial bi‐layer (PGEB) MoS2, it is demonstrated that a photodetector showed a near‐infrared photoresponse with a low dark current that is advantageous for both monolayer and bi‐layer applications. The potential expansion of the growth technique to layer‐by‐layer growth can result in boosted performance across a wide spectrum of electronic and optoelectronic devices employing MoS2.

Limiting current on periodic electron sheets in a planar diode

We consider the steady-state limiting current that can be carried by an infinite periodic array of thin electron sheets spaced by period p in a planar diode of gap voltage V and gap separation d. Our primary assumptions are as follows: (1) electron motion is restricted by an infinite magnetic field to the direction normal to the electrode surfaces, (2) all electrons are emitted from the cathode with initial kinetic energy Ein, and (3) electron motion is non-relativistic. The limiting current density, averaged over a period and normalized to the classical 1D Child–Langmuir (CL) current density (including a factor that accounts for nonzero Ein), is found to depend only on the two dimensionless parameters p/d and Ein/eV. This average limiting current density is computed from the maximum current density for which the iterative solution of a non-linear integral equation converges. Numerical results and empirical curve fits for the limiting current are presented, together with an analysis as p/d and Ein/eV approach zero or infinity, in which cases previously published results are recovered. Our main finding is that, while the local anode current density within each electron sheet is infinite in our model (that is, it exceeds the classical 1D CL value by an “infinite” factor), the period average anode current density is in fact still bounded by the classical 1D CL value. This study therefore provides further evidence that the classical 1D Child–Langmuir current density is truly a fundamental limit that cannot be circumvented.

Analysis of Lanthanum Oxide Based Double-Gate SOI MOSFET using Monte-Carlo Process.

This work proposes a Double-Gate (DG) MOSFET with a Single Material made of Silicon On-Insulator (SOI). The Lanthanum Oxide material with a high k-dielectric constant has been used as an interface between two gates and the channel. The Monte Carlo analysis has been used to determine the Conduction Band Energy (Ec) profiles and electron sheet carrier densities (ns) for a Silicon channel thickness (tsi) of 10 nm at 0.5 V gate drain-source voltages. The transverse electric fields are weak at the midchannel of DG SOI MOSFETs, where quantum effects are encountered. The Monte Carlo simulation has been confirmed to be effective for high-energy transport. A particle description reproduces the granularity property of the transport for nanoscale modeling. This work utilizes a Monte Carlo (MC) Simulation for the proposed Double Gate Single Material Silicon On Insulator MOSFET with (La2O3=2 nm) as dielectric oxide on upper and lower gate material. The electrical properties of the DG SOI MOSFETs with Lanthanum Oxide were analyzed using Monte Carlo simulation, including the conduction band energy, electric field, potential distribution, particle movement, and average velocity. The peak electric field (E) simulation results and an average drift velocity (υavg) of 6Í105 V/cm and 1.6Í107 cm/s were obtained, respectively. The conduction band energy for the operating region of the source has been observed to be 4 % to the drain side, which obtained a value of -0.04 eV at the terminal end. This proposed patent design, such as double-gate SOI-based devices, is the best suggestion for significant scalability challenges. Emerging technologies reach the typical DG SOI MOSFET's threshold performance when their geometrical dimensions are in the nanometer region. This device based on nanomaterial compounds has been more submissive than conventional devices. The nanomaterials usage in the design is more suitable for downscaling and reducing packaging density.

Kuttsukigami: sticky sheet design.

Shaping 3D objects from 2D sheets enables form and function in diverse areas from art to engineering. Here we introduce kuttsukigami, which exploits sheet-sheet adhesion to create structure. The technique allows thin sheets to be sculpted without requiring sharp folds, enabling structure in a broad range of materials for a versatile and reconfigurable thin-sheet engineering design scheme. Simple closed structures from cylindrical loops to complex shapes like the Möbius loop are constructed and modeled through the balance between deformation and adhesion. Importantly, the balance can be used to create experimental measurements of elasticity in complex morphologies. More practically, kuttsukigami is demonstrated to encapsulate objects from the kitchen to micro scales and to build on-demand logic gates through sticky electronic sheets for truly reusable, reconfigurable devices.

Reversible Charge Transfer Doping in Atomically Thin In2O3 by Viologens.

Atomically thin oxide semiconductors are emerging as potential materials for their potentiality in monolithic 3D integration and sensor applications. In this study, a charge transfer method employing viologen, an organic compound with exceptional reduction potential among n-type organics, is presented to modulate the carrier concentration in atomically thin In2O3 without the need of annealing. This study highlights the critical role of channel thickness on doping efficiency, revealing that viologen charge transfer doping is increasingly pronounced in thinner channels owing to their increased surface-to-volume ratio. Upon viologen doping, an electron sheet density of 6.8 × 1012 cm-2 is achieved in 2 nm In2O3 back gate device while preserving carrier mobility. Moreover, by the modification of the functional groups, viologens can be conveniently removed with acetone and an ultrasonic cleaner, making the viologen treatment a reversible process. Based on this doping scheme, we demonstrate an n-type metal oxide semiconductor inverter with viologen-doped In2O3, exhibiting a voltage gain of 26 at VD = 5 V. This complementary pairing of viologen and In2O3 offers ease of control over the carrier concentration, making it suitable for the next-generation electronic applications.

Hydrophilic Bonding of GaN and Diamond Substrates

Owing to their excellent properties including breakdown voltage and electron sheet charge densities, AlGaN/GaN high electron mobility transistors (HEMT) are gaining more attention for next-generation network. With the demand for high-power and high-frequency operation, as well as miniaturization, the power density has rapidly increased to ~105 W/cm2, which exceeds that on the surface of the sun (~103 W/cm2). Thus, an extremely severe self-heating effect degrades device performance and reliability, limits the power output capability, and reduces the device's lifetime. To overcome this problem, many researchers have studied the integration of the GaN devices with a diamond heat spreader1–3, which can provide a 3 times larger power density over the GaN device fabricated on a SiC substrate.To bond the GaN substrate with a single crystalline diamond substrate, which has the highest thermal conductivity among solid materials, direct bonding techniques has been developed. Several GaN/diamond bonding process has been proposed4,5; the previous processes requires ultra-high vacuum conditions, which hinders the widespread applications. The purpose of this study is to design a low-temperature bonding process of the GaN and diamond substrates under atmospheric conditions.Our research group developed the low-temperature bonding of the diamond substrate surface OH-terminated with an NH4OH/H2O2 mixture (i.e. SC1) 6,7 with other semiconductor materials (e.g. Si6,7, InP8, Ga2O3 9). In addition, the SiC substrate OH-terminated by removing the native oxide layer with HF acid could form atomic bonds with Ga2O3 through a ~1-nm-thick amorphous intermediate layer10. We hypothesize that the GaN surface functionalized by chemically removing the oxide layer can form atomic bonds with the OH-terminated diamond surface. In this study, the oxide layer on the GaN substrate was etched with an HCl acid, and then the GaN surface was bonded with the diamond surface that was functionalized with the NH4OH/H2O2 mixture.3-mm-square diamond substrates having ~3° off angled from diamond (111) surfaces were bonded on 10-mm-square self-standing GaN substrate. The bonding process is shown in the upper side of the attached figure. The diamond substrates were dipped into a mixture of NH4OH/H2O2 at 70 °C for 10 min. It consists of 10 mL of 28% NH4OH solution, 10 mL of 30% H2O2 solution, and 50 mL of deionized water (DI). Our previous study demonstrated that the diamond surface was cleaned and functionalized with OH groups6,7. On the other hand, the GaN substrate was dipped into a 5% HCl solution (10 mL of 35% HCl acid and 60 mL of DI) at room temperature (~20°C) for 5 min. After the wet chemical processes, they were rinsed using DI and dried using a flow of N2 gas. Then, the GaN and diamond surfaces were contacted with each other in a clean room (temperature: 23 °C, relative humidity: 40%). The contacted specimen was annealed at 200 °C for 2 h under a bonding pressure of 1MPa.The photograph of the diamond substrates bonded onto the GaN substrates is shown in the lower side of the attached figure. As the diamond substrates are transparent, the dispersion caused by the gap between the substrates can be observed. It is supposed that the edges were not bonded due to the warpage of the diamond surface. When the HCl treatment for the GaN surface was at room temperature, the interface was exfoliated by the shear force of 2.12 kgf (2.31 MPa). The MIL-STD 883 requires shear strength over 1 kgf for the 3-mm-square specimen. This indicates that sufficiently strong bonding is achieved by the proposed bonding process.GaN device fabricated on single crystalline diamond substrate is known as one of the most efficient heat dissipation structures11. This structure requires a low-temperature GaN/diamond bonding process. We have demonstrated the bonding between the GaN and diamond surfaces at 200 °C. The GaN/diamond integration was achieved by the simple bonding process consisting of wet treatments followed by low-temperature annealing; it doesn’t include any vacuum process and fabrication process of adhesion layers. We believe that this easy bonding process would contribute to the widespread applications of the GaN/SCD integrated device that enables extremely high-power and high-frequency operation. Figure 1

Jobsheet Elektronik berbasis Project Based Learning Matakuliah Pemograman berorientasi Objek

One of the practicum courses in the Informatics and Computer Engineering Education Study Program (PTIK) is Object-Oriented Programming. Practical learning still uses printed job sheets, so the practical process is less systematic. The research aims to produce a valid and practical electronic job sheet based on project-based learning (PjBL) in object-oriented programming courses. The research method used is research and development with the four-dimensional development model, namely: define (definition), design (design), develop (development), and disseminated (deployment). The research instruments were a validity sheet and a practicality questionnaire. The data analysis technique used is descriptive analysis in the form of percentage validity tests and practicality tests. The validity analysis was carried out by design experts and material experts, while the practicality analysis was completed by 23 students of the PTIK FKIP Bung Hatta University study program. The result of this research is a PjBL-based electronic job sheet, which was declared valid by validators at 86% based on aspects of presentation, writing, programming, content, and language. The practicality results that students fill out on the electronic job sheet meet the practical criteria of 84.6% in terms of usage, benefits, appearance, and language aspects. Therefore, this jobsheet can be used according to student needs as a digital learning resource in practical activities.

Determining the frequency of reporting laboratory data in summary sheets of patients in a pediatric ward based on the classification of diagnoses in ICD-10

BackgroundA summary of clinical findings and laboratory data is collected in patient summary sheets. The aim of this study was to determine the frequency of laboratory data reported in the summary sheets based on the classification of diagnoses in ICD-10. MethodsA descriptive-cross sectional study was performed on summary sheets of patients admitted to the pediatric ward from March 2015 to February 2016.The laboratory data of these sheets were extracted using a data collection form. Because of high number of data in each sheet and given that, depending on the diagnosis, the reported laboratory data were different, to simplify the presentation of the results the data were categorized based on patients’ diagnoses which were coded by ICD-10. ResultsA total of 10224 laboratory data were extracted, which included 47 unique data elements. The highest number of laboratory data was related to hematology (N = 14) and the lowest number was related to urine and stool analysis (N = 6). ConclusionsLaboratory data are recorded in summary sheets in accordance with patient's diagnosis. Therefore, it is possible to process the existing summary sheets and extract the registration rules, then implement these rules in hospital information systems to generate electronic summary sheets.