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The end goal of vocational training is employment, so this issue of employment and work settlement is always crucial. The Law on Vocational Education promulgated by the National Assembly on November 7, 2014, stipulated: “The general goal of vocational education is to train human resources director for the production, business, and services, have professional practice capacity corresponding to the training level; be ethical and healthy; have professional responsibility; have the ability to be creative and adapt to the working environment in the context of international integration…” However, there is still a gap between training products and the requirements of the labor market. Therefore, in other to vocational training to effectively satisfy the rising demands of the labor market, it will face both opportunities and problems in the context of global economic integration and the growth of industry 4.0. Our essay will briefly discuss the factors influencing the conformity between vocational training and the labor market.

Butt joining of ultra-thin silicon steel sheets is a major challenge because of the ultra-thin thickness, high silicon content, and the coating layer on their surfaces. For the first time, welding butt-joint of the 0.2 mm ultra-thin silicon steel sheets has been performed successfully and reported in this paper. The results show that the weld beads fabricated by the novel-GTAW process are straight, stable, and without defects. They have a narrower width on the top and a larger width on the bottom side compared to the conventional-GTAW process. The mechanical properties of the welding joints also overmatch that of the base metal, confirming good qualities of the weldment. The success of the novel GTAW process in butt weld of ultra-thin silicon steel sheets is because of its unique characteristics: First, the mechanism of the novel-GTAW torch allows removing and blowing the insulation coating layer to prevent its penetration into the melting point and its accumulation on the electrode during the welding process; thus, eliminating welding defects and electrode wear and maintaining the arc stability. Second, the novel-GTAW process enables superiorly reducing the heat input and increasing the cooling rate, which ensures the high quality of the butt weld of ultra-thin silicon steel sheets. Lastly, the shielding efficiency of the melting pool is enhanced to prevent silicon oxidation and welding defects.

Vật liệu InSb hứa hẹn được ứng dụng rộng rãi trong các nhiệm vụ dân sự và đến quân sự, từ lĩnh vực từ học cho đến quang học. Bài báo này trình bày kết quả chế tạo và khảo sát xác định hình thái cấu trúc cùng một số thuộc tính của màng mỏng InSb khi độ dày thay đổi. Các màng mỏng InSb được chế tạo bằng phương pháp lắng đọng laser xung (PLD) ở nhiệt độ 300 °C có độ dày thay đổi trong khoảng 150 nm - 2000 nm. Phép phân tích cấu trúc tinh thể (XRD) cho thấy màng mỏng kết tinh tốt ở tất cả các độ dày. Phép đo hiển vi lực nguyên tử (AFM) quan sát thấy sự tăng độ dày màng mỏng dẫn tới kích thước hạt tinh thể tăng lên (18 nm - 33 nm) và các hạt vi mô bao gồm nhiều hạt tinh thể. Ở độ dày màng mỏng < 500 nm, màng có độ nhám căn quân phương thấp (3 nm), và độ nhám này tăng lên (15 nm) khi độ dày màng ≥ 500 nm. Ảnh hiển vi điện tử quét (SEM) cho thấy tất cả các màng có cấu trúc liên tục, xếp chặt. Kết quả về cấu trúc tinh thể, hình thái vi mô được liên hệ để giải thích sự biến đổi tính chất quang của màng mỏng được chế tạo thông qua phép đo quang phổ hồng ngoại biến đổi Fourier (FTIR).

In the context of the economy's increasing demands on the quality of human resources, especially in performance capabilities, preparation of knowledge, skills and attitudes for engineering students who want to succeed in the future is key factor. As for skills, core skills play an important role to success in academic and professional practice of technical students. Analyzing the scientific basis to define the core skills of engineering students as well as studying the reality of the formation and development of these skills in schools is necessary. Qualitative and quantitative research methods are applied in this article to understand the current situation of core skills training of engineering students, data collected from three universities with engineering training in Vietnam including Ho Chi Minh City University of Technology and Education, Ho Chi Minh City University of Technology, Ho Chi Minh City University of Food Industry has shown the problems of awareness, methods, ways to practice core skills of teachers and methods of students to develop core skills.

In this study, Al-Mg alloy coatings were deposited on a C45 steel substrate by using the electric arc spray technique. The corrosion behavior of the coating was studied by electrochemical measurements and salt spray tests. The electrochemical tests were performed in 3.5 wt.% NaCl solution. Polarization tests indicated that the corrosion potential of the coating is significantly more negative than that of steel substrate after 240 hours of immersion. EIS measurements showed that after 24 hours of immersion, the total impedance increased with increasing the immersion time. This could be due to sealing of pores by corrosion products which hinder further penetration of the solution through the coating. Red rust spots did not appear on the surface of the coating after 1360 hours of salt spray test. The corrosion rate of the coating decreased with the increase in salt spray test time. After the salt spray test, the coating surface pitted and the cross section of the coating appeared with many long voids. In addition, XRD analysis proved that the main corrosion product was Al(OH)3. The results obtained indicated that arc thermal sprayed Al-Mg alloy coatings can reliably protect steel structures against corrosion in chloride-containing aqueous solutions.

Core skills are common, indispensable skills for anyone who wants to participate in learning and working in the twenty-first century. It is necessary to research and develop the core skills of engineering students to contribute to the improvement of the labor quality of the country. Research on the core skills of engineering students has not shown the specific skills of engineering students has not given a specific scale to evaluate those core skills. The core skills assessment framework is developed based on determining the structure and scale of skills. Based on the assessment framework, teachers can appropriately design the core skills development process for students. This article mainly focuses on research results that will be foundations for developing an assessment framework for the three core skills of engineering students including: technical communication skills, creative problem-solving skills, and technical system thinking skills. These are essential skills that are closely coordinated with the specialized skills of engineering students.

Background: Chronic kidney disease (CKD) is an increasingly common disease worldwide and has become a global health problem, especially in Vietnam. Cystatin C is a marker for the detection, classification, and prognosis of CKD. Cystatin C is filtered entirely through the glomerular membrane, reabsorbed, and metabolized completely in the renal tubules. In case of damage to the kidneys, glomerular filtration rate declines, and some substances increase in the blood, such as cystatin C. The concentration of cystatin C changes with damage to the renal system. Objectives: This study aimed to estimate the concentration of cystatin C and its variation in the different stages of CKD. Methods: A descriptive, cross-sectional study was conducted on 40 healthy individuals and 137 patients with CKD grade III, IV, and V in 103 Hospital. The concentration of cystatin C was estimated in all subjects. Results: Cystatin C plasma levels were significantly higher in the CKD group (9.17 ± 3.75 mg/L) than in the control group (0.82 ± 0.12 mg/L). Cystatin C plasma levels increased linearly with the serious kidney failure as the stage of CKD. Conclusions: Cystatin C is an effective marker for estimating kidney damage in CKD.

In this study, Cr3C2-25NiCr cermet coatings were fabricated by atmospheric plasma spraying on 304 stainless steel substrate. Then, the coatings were sealed with a Polytetrafluoroethylene (PTFE) emulsion by using two methods: conventional impregnation and ultrasonic vibration. The phase composition, surface morphology, porosity, permeability of PTFE emulsion into the coating, wear and corrosion resistance of the coatings were investigated. The results showed that in the PTFE sealed coatings, besides carbide phases, a PTFE phase with an hexagonal crystal structure was formed. The PTFE covered the surface of the coating. The ultrasonic vibration method increased the permeability of the PTFE emulsion into the coating by more than 2 times that of the conventional impregnation method. The PTFE sealed coating by ultrasonic vibration method had a lower porosity, higher wear and corrosion resistances in 3.5 wt.% NaCl solution than the PTFE coating sealed by conventional impregnation method and PTFE unsealed coating.

Background (including purposes): Periodontitis is a chronic bacterial infection destroying tooth supporting tissues. Although metronidazole exhibits a high effectiveness in the periodontitis treatment, its fast release and the usage frequency of several times per day can become obstacles for the local treatment. Therefore, nanotechnology is necessary to extend the duration of action and reduce the frequency of drug usage per day. The aim of this study was to formulate metronidazole nanoparticles by the nanoprecipitation method and to evaluate their physicochemical properties. Materials and methods: Metronidazole, Eudragit RS100 polymer were used in this study. Nanoparticles containing metronidazole were prepared by the nanoprecipitation method. The factors of the formulation and manufacturing process of nanoparticles containing metronidazole were investigated. The resulting nanoparticles were characterized in terms of the particle size, polydispersed index (PDI), encapsulation efficiency, etc. Results: The nanoparticles containing metronidazole were successfully prepared with the spherical shape, the particle size of 201.9 ± 5.6 nm, PDI of 0.092 ± 0.014, and entrapment efficiency of 46.28 ± 1.18%. These nanoparticles could prolong the drug release (53.45 ± 1.49% at 24 hours). The Korsmeyer-Peppas equation best described the release kinetics of the drug from metronidazole nanoparticles. Key words: Metronidazole, nanoparticle, periodontitis

Purpose In this work, Cr3C2-25NiCr coatings were deposited on 410 stainless steel substrate by using the atmospheric plasma spray technique, at varying spaying parameters. The porosity and microhardness, adhesion strength and corrosion behaviour of coatings were examined in relation to these spraying parameters. Design/methodology/approach The microstructure of prepared coatings was examined by using scanning electron microscopy. The coating compositional analysis was performed by using X-ray diffraction (XRD) technique. The corrosion resistance of coated steel was investigated by potentiodynamic polarization. Results indicate that optimal factors for minimalizing the porosity were as follows: 10 g/min feed rate, 600 A plasma current and 100 mm spraying distance. The spraying factors influencing corrosion resistance of coating were also evaluated. Findings Under this optimal condition, the porosity of coating reached its minimal value of 3.1 per cent. The microhardness and adhesion of coatings also reached their maximum values of 64.8 Rockwell Hardness scale C and 60 MPa, respectively. XRD results indicated the transformation of Cr3C2 originating from Cr3C2-25NiCr source powder into Cr7C3 and Cr23C6 crystalline phases, due to the high temperature during spraying process. The undetectable Cr3C2 peaks indicating that this phase was remained in coating at very low concentrations. The potentiodynamic polarization and salt spray tests confirmed the highest corrosion resistance for the coating prepared by optimal spraying parameters. Originality/value The application of Cr3C2-NiCr cermet carbit coating for protection of steel from corrosion-erosion is very promising.

Thermally sprayed Al2O3-TiO2 ceramic coatings provide exceptional hardness and corrosion and wear resistance, but the high velocities at which they are applied result in an inherently porous structure that requires some type of remediation. This study evaluates the effectiveness of ultrasonic aluminum phosphate sealing treatments on plasma sprayed Al2O3-40TiO2 ceramic coatings. The sealants were applied with and without ultrasonication (20-40 kHz) and were assessed using SEM/EDX analysis, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). Test data indicate that optimum sealing, corresponding to the highest values of corrosion protection and erosion resistance, are achieved under ultrasonication at 30 kHz for 5 hours.

A typical structure of thermal spray coatings consisted of molten particles, semi-molten particles, oxides, pores and cracks. These factors caused the porosity of sprayed coatings, leading to a great influence on the coating properties, especially their wear-corrosion resistance. In this study, a post-spray sealing treatment of Cr3C2-NiCr/Al2O3-TiO2 plasma sprayed coatings was carried out, then their corrosion properties were evaluated, before and after the treatment. For sealing process, aluminum phosphate (APP) containing aluminum oxide (Al2O3) nanoparticles (~10 nm) was used. The permeability of APP into the sprayed coating was analyzed by scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS). The treatment efficiency for porosity and corrosion resistance of sprayed coatings were evaluated by electrochemical measurements, such as the potentiodynamic polarization and electrochemical impedance spectroscopy. In addition, the wear-corrosion resistance of the sealed coating was examined in 3.5 wt.% NaCl circulation solution containing 0.25 wt.% SiO2 particles. The obtained results showed that APP penetrated deeply through the sprayed coating. The incorporation of Al2O3 nanoparticles into APP sealant enhanced the treatment efficiency of porosity for sprayed coating. The effect of the post-treatment on corrosion protection of the sprayed coating has been discussed.

The access transport networks are currently facing the traffic congestion problem due to rapid growth of user’s needs. The future fifth generation (5G) and beyond networks must overcome this issue to ensure that end-users have access to high-speed networks, especially in the ace of internet of things (IoTs), big data and so on. In particular, free-space optical (FSO) communication is technology that transmit large bandwidth’s signal wirelessly by using light propagating in free space and enables to realize this existing problem. In this paper, the access network configuration, i.e. transmitter to hybrid SSMF/FSO channel then to receiver, has been studied. We analyzed and evaluated system performance Q-factor of the dual polarization multiplexed 16 quadrature amplitude modulation (DP-16QAM) signal with hybrid configuration of SSMF and FSO links under atmospheric conditions such as clear air, rain and heavy weather. The lowest bandwidth of signal DP-16QAM through hybrid 80 km SSMF and 1 km FSO link in heavy weather conditions (25 mm/h) is 40 Gbaud. At the same time, the transmission distance of SSMF, FSO range, beam divergence, and receiver aperture diameter is optimized.

Groundwater table could be a significant problem during the excavation of a basement. Water through seepage forces does not only interrupt the construction work but also reduce soil strength that leads to instability of support systems. Therefore, groundwater control methods (or dewatering) before or during basement work are indispensable. Many experts have proposed both analytical and numerical analyses for simulation of the dewatering process. However, in reality, the calculation and arrangement of dewatering wells are often uncertain due to a lack of geology investigation and seasonal changes of the groundwater table. To facilitate the construction work, a quick solution needs to be proposed. In this paper, the experienced mitigation methods during basement construction are presented through case studies. In detail, deep excavation with various support systems and complex geotechnical and hydrogeological conditions have been chosen. Differences between dewatering systems in design and at actual site conditions are also shown. Thereby, an optimal design would be obtained in the future.

Recovering MS Office password using the Brute-Force method with multi-core CPUs and GPU support has been studied in several works, and obtained some success. In these works, the combination of multi-core CPUs and computer clusters in the computing process is essential in order to increase the processing speed. In this paper, we propose a method for recovering Microsoft Office passwords by an exhaustive method based on a parallel computing system with multiple compute nodes and also take advantage of multi-core capabilities in each node. Moreover, this paper presents an assessment of the impact of communication delays on the performance of a parallel computing system.

In this study, the effect of oxygen in the shielding gas on the material flow behavior of the weld pool surface was discussed to clarify the dominant driving weld pool force in keyhole plasma arc welding (KPAW). To address this issue, the convection flow on the top surface of weld pool was observed using a high-speed video camera. The temperature distribution on the surface along keyhole wall was measured using the two-color pyrometry method to confirm the Marangoni force activity on the weld pool. The results show that the inclination angle of the keyhole wall (keyhole shape) increased especially near the top surface due to the decrease in the surface tension of weld pool through surface oxidation when a shielding gas of Ar + 0.5% O2 was used. Due to the change in the keyhole shape, the upward and backward shear force compositions created a large inclination angle at the top surface of the keyhole. From the temperature measurement results, the Marangoni force was found to alter the direction when 0.5% O2 was mixed with the shielding gas. The shear force was found to be the strongest force among the four driving forces. The buoyant force and Lorentz force were very weak. The Marangoni force was stronger than the Lorentz force but was weaker than shear force. The interaction of shear force and Marangoni force controlled the behavior and speed of material flow on the weld pool surface. A strong upward and backward flow was observed in the case of mixture shielding gas, whereas a weak upward flow was observed for pure Ar. The heat transportation due to the weld pool convection significantly changed when only a small amount of oxygen was admixed in the shielding gas. The results can be applied to control the penetration ratio in KPAW.

Các thành tạo cát ven biển tỉnh Bình Thuận được chia là 4 đơn vị địa mạo - trầm tích tương ứng với 4 đơn vị cấu trúc địa chất: đồng bằng - lagun; cồn cát và thềm cát ven biển; đới thủy triều; đáy biển nông ven bờ. Các thành tạo cát Đệ Tứ ven biển Ninh Thuận càng cổ phân bố ở độ cao càng lớn chứng tỏ các quá trình chuyển động nâng kiến tạo của khu vực ven biển tỉnh Bình Thuận xảy ra mạnh mẽ trong Đệ Tứ. Nghiên cứu thành phần vật chất, môi trường trầm tích, tuổi tuyệt đối (TL và tectit) các thành tạo cát ven biển tỉnh Bình Thuận cho phép phân chia cát trong khu vực làm 5 đơn vị trầm tích mỗi đơn vị tương ứng với 5 chu kỳ trầm tích (Q11, Q12a, Q12b, Q13a, Q13b - Q2). Mỗi chu kỳ trầm tích tương ứng với một chu kỳ thay đổi mực nước biển toàn cầu trong đó có một pha biển thoái thấp (LST), một pha biển tiến (TST), một pha biển thoái cao (HST). Cát ven biển Bình Thuận có nguồn gốc biển thuộc tướng đê cát ven bờ liên quan đến sự dao động mực nước biển toàn cầu do ảnh hưởng của 5 pha băng hà và gian băng trong Đệ Tứ. Màu vàng, màu đỏ nhạt và đỏ rượu vang của cát là màu thứ sinh được thành tạo trong điều kiện cổ khí hậu khô nóng, khô ấm xen kẽ kết hợp với quá trình nâng và hạ mực nước ngầm theo chu kỳ tạo ra sự thấm nhuộm các oxit sắt quanh các hạt thạch anh.

For mainland-island communication applications, radio-over-fiber (RoF) links which have been commonly designated for short-reach access networks need to be re-designed due to the long geogrgphical distance nature. In this paper, we present a calculating model of long-distance RoF communication systems that connect mainland and islands using intensity modulation (IM) technique, two erbium-doped fiber amplifiers (EDFAs) and coherent receiver for transferring mobile RF signal. Signal and noise powers, signal-to-noise ratio (SNR) and bit-error rate (BER) of these systems are calculated and determined. We then build algorithm chart to find out system's essential parameter values including transmitter power, local oscillator power, EDFA's Gains, EDFA's position on the link so that BER values at the receiver are in the interval of [10−14-10−10] corresponding to different lengths (200–300) km. Next, we write and make MatLab-based program run to show system performance under the impacts of fiber link length, transmitter's laser power, and receiver's local oscillator. The results could be used effectively in calculating, designing and operating the long-distance RoF systems.

The paper presents the Kriging technique based on Matlab environment applied to interpolate the value of all points in the interpolation range from porosity values obtained from 13 wells of lower Miocene reservoir, ST Xam oil field. The MATLAB function meshgrids are used to create the interpolated cell (cell-Kriging) instead of point discrete interpolation. After selecting the Variogram model with nugget values and the correlation threshold (in scope), the next step is Kriging porosity values which regression permeability values. Finally, displays the values in the cells and interpolated coordinates X, Y, respectively. With input data the first mission is to analyze this set, select the necessary parameters and removal of useless data, and assess the scope of application of each type of data. Then combine the document with wellogging interpretation results to determine reservoirs and the layered in which filter out the corresponding data averaging and conducting. Based on the selected average value of the corresponding products in each well for each subclass, calculate the results of an empirical Variogram model as the basis for Kriging weighted matrix. The last work is to calculate error and evaluate the reliability of the Kriging results. The error of porosity model are minor and distributed apropriately with kriging range. However the results are numerous correlation. The permeability experiment results are collected just from 03 points, therefore the ultimate solution is recurred porosity from porosity Kriging results.

Recent survey results indicate the presence of Tertiary sedimentary basins with hydrocarbon potential in the boundaries of Vietnam continental shelf. These basins were perhaps formed in the Early Oligocene on the Mesozoic basement of continental crust and were filled with mainly deltaic clastic sediments. From very early Miocene these basins have linked together and became wider. Sediments of marine and prograding delta facies accumulated and widespreaded on the whole continental shelf. At the Middle Miocene to present-day the opening of the Bien Dong Sea (Vietnam East Sea), the regional tectonic subsidence and the eustatic fluctuation had created sedimentary formations of open and deep marine facies with turbidite shale, platform carbonate including reef build-up. Andesite and basalt extrusion occurred in form of dykes resulting from tectonic inversions in Late Oligocene, in the beginning of Middle Miocene, particularly in Late Miocene-Pliocene. These Tertiary sedimentary basins are expected to have hydrocarbon potential and need to be investigated and explorated adequately. The main risk is the drilling technology, the exploitation in the deep sea and high investment cost.

In this paper, a calculating model of Digitized Radio over Fiber (RoF) system using EDFA amplifier and Coherent receiver is proposed. We then investigate Signal-to-Noise Ratio (SNR) in different parts of the system and establish SNRtotal equation at the output of RF signal recovery in three cases: Direct Detection, Coherent Detection and Combined EDFA-Coherent Detection. Next, we write and run MatLab-based program to draw graphs that show system performance such as BER, SNR versus signal power at receiver input (PS), versus signal power launched to the fiber (PTX), versus transmission length of the system (D). Then, the performance comparison of Direct Detection, Coherent Detection and Combined EDFA-Coherent Detection is carried on. At the same time, 8 different demodulation methods in Combined EDFA-Coherent Detection are investigated and presented on graphs. The comparison and numerical results show that thanks to using Combined EDFA-Coherent Detection in Digitized RoF system, the signal quality is enhanced remarkbly. Some suitable demodulation methods are also proposed for applications.

In this paper, we reference the idea of work[1] to investigate more complicated system where EDFA amplifier and Coherent receiver are used to enhance signal quality. Calculating model of RoF transport system using direct modulation technique at transmitter, EDFA and Coherent receiver is proposed. We calculate and determine BER and SNR of the NRZ system using many kinds of different silica-doped materials of optic fiber. We then build algorithm chart to find out system essential parameters such as EDFA's Gain, EDFA's position for enhancing SNR and reducing BER at the end of system corresponding to different lengths (from 100 km to 180 km). Next, we write and make MatLab-based program run to draw graphs that show system performance such as BER, SNR versus fiber link length with different silica-doped materials. The results could be used effectively in calculating, designing and operating the RoF systems.

In this paper, we propose calculating models of Terrestrial DWDM cascaded EDFAs Fiber Optic Communication Links using Hybird Fiber Amplifier (HFA) including combination of Distributed Raman Amplifier (DRA) and EDFA, and build algorithm charts to optimize parameters including signal power per channel launched fiber, EDFAs gain, pump power of Raman amplifier for improving optical Signal-to-Noise ratio (OSNR) at the end of link. Then, algorithm-based numerical calculating (MathCAD program) is applied in typical system (WDM Nation-wide links in Vietnam). Optimized results show that the OSNR can be increased by (1-5) dB comparing with that in cases of parameters chosen by experience way.