bluuebunny/crossref_metadata_2025 huggingface dataset:
INFLUENCE OF SATURATION MAGNETIZATION AND VISCOSITY ON SPECIFIC LOSS POWER FOR CoFe2O4 AND MnFe2O4 MAGNETIC NANOPARTICLES
Authors: Nguyen Luu Huu
Published: April 2018

Magnetic nanoparticles absorb energy from external alternating magnetic field to create ananosized heating source. Specific loss power (SLP) is affected strongly by several magneticparameters of material and viscosity of nanofluid. In this study, the specific loss power asdependent on saturation magnetization was calculated for hard ferrite CoFe2O4 (K = 290 kJ/m3)and soft ferrite MnFe2O4 (K = 3 kJ/m3) with two values of viscosity in biological range 1-2 mPas.Besides, we investigated the experimental dependence SLP on their saturation magnetizationwhile changing viscosity using agar powder. A large change of slopesSLPMwas found for CFOwhen the viscosity changes; whereas it remained almost unaffected by the variation of viscosityfluid of MFO. All calculation and experimental results are discussed via the competitionbetween Néel and Brown relaxation.
LOW TEMPERATURE PHASE OF THE RARE-EARTH-FREE MnBi MAGNETIC MATERIAL
Authors: Vuong Nguyen Van
Published: April 2018

The Low Temperature Phase (LTP) content determines the spontaneous magnetization Ms of the rare-earth-free hard magnetic material MnBi. LTP in MnBi samples alloyed by the arc-melting is timely developed when they are annealed at the annealing temperatures Ta < 340 oC. Because of the complexity of the phase diagram of MnxBi(100-x) system, the content hardly reaches the value of 100 wt%. Based on the phase diagram of MnxBi(100-x) system, the upper limit * was calculated and 59.8 wt% is the highest content which can be reached when the alloy is isothermally annealed for a long time. The time-dependent behavior of (t) reveals that the LTP is formed from Mn and Bi phases by the diffusion mechanism. The time-dependent diffusion equation has been used to investigate the diffusion process between Mn and Bi in order to form the LTP. The comparison between the theoretical and experimental data allowed to estimate the mutual diffusion coefficient D 510-12 cm2/s. This small value of D is suggested due to not only the low value of Ta necessary for forming LTP but the high surface tension of Bi melted at Ta as well. The calculated results showed that the size distribution of Mn grains embedded in the Bi matrix affected the dependence (t), enhancing and inhibiting in the samples annealed for short and long times, respectively. To increase over *, the anneal at Ta superimposed by the small temperature gradient of 2 oC/cm has been performed. This temperature-gradient driven annealing technique helped to overcome * and reach the value of 83 wt% which corresponds to the Ms = 60 emu/g measured at the field strength of 4 Tesla.
STRUCTURE, ELECTRICAL PROPERTIES, AND APPLICATION POSIBILITY AS SOLID OXIDE FUEL CELLS CATHODE MATERIALS OF (La2NiO4±δ)1-x(BaTiO3)x(x=0.0-0.5) COMPOSITES
Authors: Anh Thu Le Thi
Published: April 2018

(La2NiO4±δ)1-x(BaTiO3)x (LNO/BTO), x=0.0, 0.05, 0.2, 0.3, 0.5 composites were prepared and investigated in structure and electrical properties. Single phase La2NiO4±δ component was obtained by sintering at 1000 oC during 12 h in air. Electrical conductivity was measured by 4-point probe method in wide temperature region above room temperature. Experiment showed that the highest conductivity was obtained in x=0.3 composite sample. Glass shell-nanocrystallite core structure of grains plays important role for this conducting enhancement. Conducting behavior of composites change from metal to semiconductor in the temperature interval of 400 to 700 oC. The LNO/BTO systems with acceptable electrical conductivity in such temperature interval are suitable for making cathode materials in solid oxide fuel cells.
NGHIÊN CỨU TÍNH CHẤT VÀ HÌNH THÁI CẤU TRÚC CỦA VẬT LIỆU COMPOZIT POLYETYLEN/COPOLYME ETYLEN VINYL AXETAT/GYPSUM BIẾN TÍNH NATRI DODECYL SUNFAT
Authors: Hà Khương Việt
Published: April 2018

Vật liệu compozit trên cơ sở polyetylen tỉ trọng cao/copolyme etylen vinyaxetat (HDPE – EVA) và hạt gypsum phế thải đã được chế tạo bằng phương pháp trộn nóng chảy trên thiết bị trộn nội Haake. Gypsum được biến tính (Mgyp) bề mặt bởi natri dodecyl sunfat (SDS) ở 206oC để tăng cường tương hợp với các polyme. Phân tích phổ hồng ngoại Mgyp cho thấy sự có mặt của nhóm hidrocacbon trong SDS trên bề mặt gypsum. Đánh giá tính chất cơ học cho thấy modun đàn hồi của vật liệu compozit sử dụnggypsum biến tính tăng hơn so với mẫu sử dụng gypsum không biến tính. Kết quả đánh giá khả năng cháy của vật liệu compozit cho thấy, gypsum biến tính làm giảm đáng kể tốc độ cháy của vật liệu. Kết quả nghiên cứu hình thái cấu trúc của vật liệu bằng phương pháp hiển vi điện tử quét phát xạ trường (FESEM) đã khẳng định biến tính gypsum bằng SDS đã cải thiện khả năng tương hợp và kết dính của gypsum với các polyme tốt hơn so với gypsum chưa biến tính.
INVESTIGATION ON STRUCTURAL AND FERROELECTRIC PROPERTIES OF Bi3.25La0.75Ti3O12 THIN FILMS
Authors: Dung Tran Van
Published: April 2018

Lanthanum doped bismuth titanate (Bi3.25La0.75Ti3O12 abbreviated as BLT) has been known as one of typical materials for Bi-layered perovskite structure which possess several unique properties such as good fatigue with metal electrode and stable remanent polarization, hence it has potential applications in ferroelectric random access memory. In this work, the BLT thin films were fabricated on Pt/TiO2/SiO2/Si substrates by using a solution process, and then their features including crystal structure, surface morphology, and electrical properties were characterized by using X-ray diffraction system (XRD), scanning electron microscopy (SEM), and electrical measurement system (Radiant Precision LC 10), respectively. The obtained results point out that the BLT thin film annealed at 725 oC is mostly optimum from a viewpoint of film quality and ferroelectricity. In particular, the optimum BLT thin film having a thickness of 200 nm does not contain any cracks on the sample surface, and the grain size is closed to 400 nm from SEM observation. XRD patterns imply that the BLT thin film had stoichiometric structure with preferred orientations of (117) and (006), when annealed at temperatures higher than 725 oC. In addition, we found the influence of La (0.75) dopping on c-axis-oriented growth of BLT thin films is clear from the structural analysis. The remanent polarization of optimum BLT thin film is approximately 10 μC/cm2, but the ferroelectric hysteresis loops are not saturated at low applied voltages.
POLARIZATION DEPENDENCE IN OPTICAL REFLECTION AND TRANSMISSION OF OPAL PHOTONIC CRYSTALS
Authors: Tuyen Le Dac
Published: April 2018

High-quality opal photonic crystals were fabricated by self-assembling of monodispersed SiO2 nanospheres with a thermal-assistant cell method. The angle- and polarization-resolved optical reflection and transmission of an artificial opal were studied. A strong anisotropy in the intensity and the full width at half maximum of reflection and transmission spectra of the s- and p-polarized light was observed along the L-U (L-K) direction of the first Brillouin zone, and these differences become more pronounced in the vicinity U (K) point. The observed polarization anisotropy of optical properties is caused by symmetry characterization of polarized light and opal structure. The obtained results agree fairly well with calculated photonic band structure, which is also compared with predictions based on the group theory.
FABRICATING THE MICROFLUIDIC CHIP WITH LENGTH-AND-DIAMETER RATIO OF CHANNEL AROUND 3000
Authors: Thanh Giang Le Thuy
Published: April 2018

Microfluidics is a device that accurately controls the motion of fluid flow with a very small amount of liquid. This field has been studied with many empirical applications in physics, chemistry, biochemistry, nanotechnology and biotechnology. Depending on particular application, the length-and-diameter ratio of channel is designed specifically in order to gain the highest efficiency for physical response and chemical reaction, etc. In this report, microfluidic chips, based on PDMS material, fabricated by soft lithography with the length-and-diameter ratio of channel 3000 times, have been fabricated for the research on biomedical orientation.Illustration of microfluidic chip with straight and spiral shape and the length-and-diameter ratio of channel around 3000.
THE FABRICATION OF Ag NANOPARTICLES LOADED TiO2 NANOTUBES BY PHOTOREDUCTION METHOD AND THEIR PHOTOCATALYTIC ACTIVITY
Authors: Viet Pham Van
Published: April 2018

In this paper, we survey the effect of the photoreduction (illumination) time and the annealing temperature on the formation of Ag nanoparticles supported on TiO2 nanotubes (Ag/TNTs). The morphology, crystal structure and compositions were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS), respectively. The results showed that Ag nanoparticles are supported on TNTs and the amount of Ag nanoparticles could be controlled. The morphology of TNTs can be changed by the photoreduction time and the annealing temperature.
ION Mn4+ VÀ Cr3+ TRONG TRƯỜNG TINH THỂ α-Al2O3
Authors: Son Nguyen Manh
Published: April 2018

Vật liệu phát quang α-Al2O3 pha tạp Mangan (Mn4+), Crôm (Cr3+) được chế tạo bằng phương pháp nổ dung dịch urê-nitrat, sử dụng chất khử urê, ở nhiệt độ thấp. Các kết quả XRD cho thấy mẫu có cấu trúc pha lục giác. Phổ kích thích phát quang của α-Al2O3: Mn4+ và α-Al2O3: Cr3+ gồm hai dải rộng có cực đại ở 405 nm và 558 nm, tương ứng với các chuyển dời điện tử của ion Mn4+ và Cr3+ từ 4A2 → 4T1 và 4A2 → 4T2. Kết quả xác định Dq/B chứng tỏ các ion này chiếm vị trí của trường tinh thể mạnh trong mạng nền.
NGHIÊN CỨU MỐI LIÊN HỆ CẤU TRÚC RỖNG NANO - SỰ THẨM THẤU KHÍ CỦA MÀNG GHÉP MẠCH ĐIỆN CỰC POLYMER SỬ DỤNG CHO PIN NHIÊN LIỆU
Authors: Anh Nguyễn Hoàng
Published: April 2018

Màng điện cực polymer poly(styrenesulfonic acid) ghép mạch bức xạ với poly(ethylene-co-tetrafluoroethylene) (ETFE) được tạo ra bằng phương pháp trùng hợp khơi mào bức xạ gamma để ghép styrene vào bề mặt tạo thành phim ghép mạch grafted-ETFE, sau đó sunfo hoá các màng đã ghép mạch để tạo màng dẫn proton ETFE-PEM. Mối liên hệ giữa cấu trúc rỗng kích thước nano với sự thẩm thấu khí qua màng của ETFE-PEM với mức độ ghép mạch (GD) biến đổi rộng (0127 %) được nghiên cứu bằng phổ thời gian sống của bức xạ huỷ positron (PALS). Phổ PAL của tất cả các phim ghép mạch grafted-ETFE và màng dẫn proton ETFE-PEM cho thấy sự tồn tại của hai loại o-Ps tương ứng với sự hình thành của chúng trong các cấu trúc rỗng có kích thước nhỏ hơn (V3) và lớn hơn (V4). Giá trị V3 (0,0440,075 nm3) và V4 (0,170,26 nm3) của màng ghép grafted-ETFE lớn hơn không đáng kể so với màng điện cực polymer ETFE-PEM chứng tỏ rằng cấu trúc rỗng kích thước nano của màng được hình thành và ảnh hưởng chủ yếu tại bước ghép mạch, không phải bước sunfo hoá. Trên toàn dải giá trị GD, giá trị V3 của cả phim ghép mạch grafted-ETFE và màng dẫn proton ETFE-PEM nhỏ hơn ba đến bốn lần giá trị V4, do đó sự thẩm thấu khí được dự đoán sẽ đi qua màng chủ yếu tại các vùng vô định hình của ETFE có chứa vật liệu ghép mạch polystyrene/polystyrenesulfonic acid. Khi giá trị GD tăng, giá trị V4 giảm, dẫn tới giảm thẩm thấu khí qua màng, do đó giữ được tính bền hoá học để sử dụng cho pin nhiên liệu.
TỔNG HỢP VÀ ĐẶC TRƢNG VẬT LIỆU HẤP THU DẦU TỪ SỢI RƠM
Authors: Vân An Hoàng Thị
Published: April 2018

Các sự cố tràn dầu xảy ra thường gây hậu quả nghiêm trọng đến môi trường và hệ sinh thái vì vậy việc tìm ra các giải pháp để khắc phục hậu quả của sự cố tràn dầu có ý nghĩa vô cùng quan trọng. Trong nghiên cứu này, quá trình axetyl hóa sợi rơm và tính chất hấp thu dầu của sản phẩm được nghiên cứu. Trên cơ sở khảo sát chi tiết các yếu tố ảnh hưởng đến quá trình axetyl hóa, có thể rút ra điều kiện tối ưu như sau: tỉ lệ sợi rơm/anhydit axetic =1/10, [NBS] = 2 %, thời gian phản ứng 120 phút, nhiệt độ phản ứng 90 0C và mức độ axetyl hóa đạt được 30,6 %. Sợi rơm và sợi rơm axetyl hóa được đặc trưng bởi phổ hồng ngoại biến đổi Fourier (FTIR), hiển vi điện tử quét (SEM) và nhiễu xạ tia X (XRD). Tính chất hấp thu dầu đối với dầu thô và khả năng tái sử dụng của vật liệu cũng được nghiên cứu, đánh giá.
SYNTHESIS AND CHARACTERIZATION OF LAURYL METHACRYLATE – GRAFT - POLYPROPYLENE FIBER
Authors: Ha Hoang Thu
Published: April 2018

The graft polymerization of lauryl methacrylate (LMA) onto polypropylene fiber (PP) was investigated by using 2,2’-azobisisobutyronitrile (AIBN) as initiator. The grafting was influenced by AIBN concentration, monomer concentration, the reaction time and reaction temperature. On the basis of a detailed investigation of these factor, the optimal conditions for the grafting of LMA onto PP with the said initiator were as follows: [AIBN] = 0.015 mol/l, [LMA] = 1.25 mol/l, reaction time 240 min, reaction temperature 80 oC, in which the graft yield (%GY) of 15.7 % was obtained. Characterization of the polypropylene fiber-graft-lauryl methacrylate was done by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM).
XÁC ĐỊNH CẤU TRÚC VÙNG CHUYỂN TIẾP CỦA MÀNG ĐIỆN CỰC POLYMER SỬ DỤNG CHO PIN NHIÊN LIỆU: TIẾP CẬN TỪ VIỆC HIỆU CHỈNH QUY LUẬT POROD
Authors: Hải Huỳnh Thị
Published: April 2018

Poly(styrenesulfonic acid)-grafted poly(ethylene-co-tetrafluoroethylene) (ETFE-PEMs) được tổng hợp bằng phương pháp chiếu xạ gamma trong đó phim ban đầu ETFE được chiếu xạ và ghép mạch bởi monomer styrene (Grafted-ETFE) sau đó là sunfo hoá để tạo thành màng dẫn proton. Cấu trúc vùng chuyển tiếp của ETFE-PEMs được nghiên cứu như là hàm của mức độ ghép mạch bức xạ (GD) bởi phương pháp tán xạ tia X góc nhỏ bằng cách so sánh với các phim ban đầu grafted-ETFE và ETFE. Bởi vì sự lệch của quy luật Porod đã được phát hiện do sự tồn tại của thăng giáng mật độ electron và sự khuếch tán vùng chuyển tiếp nên việc hiệu chỉnh quy luật Porod đã được thực hiện bằng cách sử dụng hàm mô tả mật độ electron tại vùng chuyển tiếp dạng hình tam giác để tính toán bề dày vùng chuyển tiếp của các phim. Kết quả cho thấy rằng giá trị bề dày vùng chuyển tiếp (1 - 2 nm) phụ thuộc vào mô hình mô tả mật độ electron tại vùng chuyển tiếp và mô hình để hiệu chỉnh thăng giáng mật độ electron. Chú ý rằng bề dày vùng chuyển tiếp thay đổi theo quy trình tổng hợp mẫu cũng như theo mức độ ghép mạch và ảnh hưởng đến tính dẫn proton và độ bền cơ học của PEM sử dụng cho pin nhiên liệu.
FABRICATION OF Fe3O4 MAGNETIC FLUID BY POLY (ACRYLIC ACID) FOR BIOMEDICAL APPLICATIONS
Authors: Kim Oanh Vuong Thi
Published: April 2018

Fe3O4 nanosystems of different sizes were synthesized by thermal decomposition method in organic solvent. Magnetic fluid based on Fe3O4 nanoparticles was prepared by using poly acrylic acid (PAA) as a phase transfer agent. The structure, morphology and magnetic properties of samples were studied by: X-ray diffraction patterns (XRD), transmission electron microscope (TEM), and vibrating sample magnetometer (VSM). XRD results indicated that all samples had spinel single phase structure with average crystaline size less than 15 nm. TEM images showed that the average size of samples were nearly equal to those of XRD. The highest value of saturation magnetization obtained at room temperature for the sample synthesized at optimal reaction time and temperature (2 hours and 298 oC, respectively) after phase transferring was 75 emu/g. The linkage between magnetic nanoparticles’ surface and functional groups of PAA was confirmed by FT-IR spectra. Simultaneously, the particle size and stability of magnetic fluid were evaluated by DLS and Zeta potential. These results demonstrated the narrow size distribution and high stability of nanosystem. The important point was that the phase transfer contributed to enhance of saturation magnetization of samples (about 5 % of the initial ones). Magnetic fluid based on Fe3O4 nanoparticles with high homogeneity, high saturation magnetization and good stability promised a potential application in biomedical, especially in magnetic hyperthermia and contrast-enhanced magnetic resonance imaging.
PREPARATION OF ACTIVATED CARBON FROM SUGARCANE BAGASSE USING ZnCl2 FOR THE REMOVAL OF Cu (II) ION FROM AQUEOUS SOLUTION: APPLICATION OF RESPONSE SURFACE METHODOLOGY (RSM)
Authors: Thuan Tran Van
Published: April 2018

This study aimed at preparing low cost activated carbon (AC) from sugarcane bagasse by ZnCl2 activation and evaluating the effects of synthesis conditions and variables using the response surface methodology (RSM) approach for the adsorption of Cu (II) ion from aqueous solution by the synthesized ACs. From the analysis of variance (ANOVA), the most influential factors including activation temperature, impregnation ratio and activation time on each experimental design response were investigated. The optimized conditions for preparation of AC and removal of Cu (II) ions were identified with the activation temperature of 673 K, impregnation ratio of 1.5 and activation time of 35.2 minutes. An optimized conditions based–test experiment with 48.8 % of AC yield and 92.3 % Cu (II) ion removal was observed.
CHẾ TẠO VÀ KHẢO SÁT TÍNH CHẤT NANOCOMPOZIT GRAPHEN/POLYPYROL
Authors: Long Ngô Cao
Published: April 2018

Quá trình chế tạo graphen bằng phương pháp oxi hóa hóa học graphit trong môi trường axit thu được sản phẩm với các nhóm chức chứa oxi trên lớp graphen. Vật liệu này có độ dẫn kém do vậy cần khử hóa graphen oxit bằng hydrazyl, thu được vật liệu mới (RGO) có độ dẫn tốt. RGO sau khi khử hóa được biến tính bề mặt với polystyren sunfonat nhằm tăng cường khả năng phân tán. Sử dụng vật liệu này chế tạo nanocompozit graphen/ polypyrol bằng phương pháp trùng hợp tại chỗ. Kết quả cho vật liệu nanocompozit có tính dẫn điện tốt, các hạt nanocompozit tạo thành có kích thước khoảng 250 nm.
SCREENING OF PEPTIDE RECEPTOR SEQUENCES FOR AMITROL DETECTION USING CHROMATOGRAPHIC BIOPANNING
Authors: Lien Thuong Nguyen Thi
Published: April 2018

Endocrine disrupting chemicals (EDCs) have been known as health threatening compounds and much attention has been paid in a research related with detection and/or removal from food sources and living environment. Amitrol, classified as one of EDCs, is hard to be detected and removed due to its chemical characteristics such as small molecular weight, low reactivity and high solubility. Some of organic compounds were investigated to find the corresponding binding peptides to those by biopanning protocol. However, peptides with affinity to amitrol remained to be searched for because amitrol is hard to be used as a target of free form or immobilized form in common biopanning protocol. In our experiment, amitrol was successfully immobilized on CDI monolithic column with the presence of catalyst and hence was able to be applied as a target component in biopanning. Chromatic biopanning was carried out as a fast and convenient method for the selection of peptides with high affinity to amitrol. Chemical and physical methods were combined in elution step to improve the selection efficiency for strong binders. After multiple rounds of negative screening and positive screening, high affinity peptide sequences were isolated from initial peptide libraries. Applications of these peptide sequences can be widened from bio adsorption to biosensor for environment pollution control.
ECO-FRIENDLY SYNTHESIS OF GOLD NANOPARTICLES USING AVERRHOA CARAMBOLA L.
Authors: Nhat Hang Nguyen Thi
Published: April 2018

In this work we report an eco-friendly method for the synthesis of gold nanoparticles (AuNPs) using Averrhoa carambola L. fruit extract at different temperatures. AuNPs were formed and coated conjugatedly with the components of aqueous fruit extract of Averrhoa carambola L. as verified under UV-vis spectroscopy, transmission electron microscopy (TEM) and used for testing of antimicrobial activity. AuNPs - Averrhoa carambola L. extract combination showed synergistic effect on the antibacterial activity as judged by well diffusion method. AuNPs alone did not showed the antibacterial activity, and Averrhoa carambola L. extract had the inhibition zone of 8.8 ± 1.08 mm, while the combination of AuNPs - Averrhoa carambola L. extract showed 16.33 ± 2.33 mm inhibition zone when Averrhoa carambola L. extract was 285 mg/ml. Therefore, green-synthesized AuNPs by our protocol are potential to biomedical applications.
ANAEROBIC DIGESTION OF SLUDGE IN WASTEWATER TREATMENT PLANT FOR ENERGY RECOVERY – A CASE STUDY OF HANOI URBAN DISTRICT
Authors: Thuy Bui Thi
Published: April 2018

In a wastewater treatment plant (WWTP) energy optimization is a big concern whilst sludge stabilization and energy recovery by anaerobic digestion implementation has recently gained importance. The calculation of an urban district level (selected as Long Bien) with 352,000 populations showed that with a total energy required of 39,750 kWh per day in WWTP, it could be supplied by utilization of biogas production, varying from 0% to ~ 43.44 % depending upon the non-application or application of anaerobic digestion for sludge treatment. In mesophylic anaerobic digestion, the biogas yields production of the calculated WWTP was obtained at 3,710 m3/day; equal to 8,394 kWh power and 13,919 kWh heat per day. As a conventional treatment process, centrifugal dewatering of sludge required an additional energy of 1,376 kWh per day for recycling, pumping, mixing as well as transporting sludge. The conclusion was that anaerobic digestion can reduce the green-house gases versus conventional dewatering. The results from this research can thus demonstrate the applicability of anaerobic digestion on conversion of waste to energy, looking forward to resource recovery.
APPLICATION OF IRON-BASED ADSORBENT (FEOOH) TO REMOVE HYDROGEN SULFIDE (H2S) FROM BIOGAS
Authors: Uan Do Khac
Published: April 2018

Biogas generated during the anaerobic digestion of piggery wastes is considered as one of the renewable energy sources. This biogas is methane-rich, based on a typical composition of 60 - 70 % methane (CH4). However, trace amounts of undesirable compounds, such as hydrogen sulfide (H2S) is also present, which hinder their use as it is very toxic and corrode the equipment. In this study, a lab-scale adsorption system was conducted to removal H2S from biogas collected at Thanh Hung pig farm (Thanh Oai district, Hanoi). The initial biogas contained high CH4 concentration of 72 %, and the H2S concentration was about 1995 ppm. The iron-based adsorbent (FeOOH) with the particle size of 0.50-1.18 mm was used for H2S purification. The system was operated continuously at various biogas flow rates from 0.5 to 3 L/min. Breakpoint of FeOOH appeared after 1,038 min. The adsorption capacity was estimated up to 0.18 g H2S/g FeOOH. A longer empty bed contact time increased the amount of H2S that was adsorbed up until the time of breakpoint. During operation, the temperature in the air and in biogas was varied insignificantly in the range of 29 to 32 oC. However, the humidity was much different between in the ambient air (56 %) and in biogas (87 %). In conclusion, FeOOH has high capacity for H2S purification to produce high quality purified biogas with H2S concentration of below 100 ppm which could be used for electrical generation.
ENERGY RECOVERY FROM ACTIVE SLUDGE OF WASTEWATER TREATMENT PLANTS
Authors: Chau Ngan Nguyen Vo
Published: April 2018

Due to fast growth of industrial sector, the volume of sludge from wastewater treatment systems increases, and this becomes a big problem to the environment. The cost for treatment of sludge is high and requires typical landfill for disposal. This study suggested recovering energy from the sludge of wastewater treatment plants through an anaerobic fermentation process. Sludge from wastewater treatment plants of fish processing factory (C) and shrimp processing factory (T) were collected for the testing of this study. The 20 L lab-scale batch anaerobic digesters were used to ferment sludge which has different humidity of 85 - 90 % and of 95 - 98 %. The biogas yield of the treatment C 85-90 is 305.3, C 95-98 is 444.2, T 85-90 is 144.4, and T 95 - 98 is 171.1 L/kg ODMfermented. After 10 operation days, the percentage of CH4 in the produced biogas was around 50 % which is high enough for energy purposes. The result clearly confirms that sludge from wastewater treatment plants not only is possible treated in anaerobic digesters but also is able to be applied as input material to produce biogas for energy consumption.
WATER MANAGEMENT AND METHANE EMISSION FROM RICE CULTIVATION: A CASE STUDY IN AN GIANG PROVINCE, VIET NAM
Authors: Linh Duong Mai
Published: April 2018

Rice cultivation causes the emission of CH4 consequenced to the global warming. Reduction of irrigation in rice cultivation is not only saving water resources but also reducing greenhouse gases emission. The objectives of this study was to determine impacts of water management on the emission of CH4 and rice yield. Experiment was conducted in field conditions in An Giang province, Viet Nam with three treatments as continuous flooding (CF), An Giang Alternative Wetting and Drying (AAWD) which is mostly applied by farmers in An Giang province-Viet Nam, and Alternate Wetting and Drying (AWD). Water levels in the field +5 cm, ± 5 cm and -15 cm were controlled higher, fluctuated and lower than soil surface, respectively for CF, AAWD and AWD. CH4 emission determined every week during 13 weeks of the experiment. Rice yield was determined in 1 m2 at the end of the experiment. The results showed that AWD and AAWD, respectively decreased 78.7 % (p < 0.05) and 6.8 % (p > 0.05) CH4 emission compared to the CF 11.9 mg CH4/m2/h. The rice yield of CF was 6.32 ton/ha lower than AAWD 7.8 ton/ha (p < 0.05) but not different with AWD 6.67 ton/ha. AAWD had higher rice yield but same emission than the CF. Farmers in An Giang province should consider application of AWD in rice cultivation in term of saving water and reduction of CH4 emission.
FORECASTING THE WATER QUALITY AND THE CAPACITY OF RECEIVING WASTEWATER OF THE DONG NAI RIVER UP TO 2020
Authors: Anh Nguyen Viet
Published: April 2018

Dong Nai river, the largest river system in the South East region, flows through five provinces in the South East area. Dong Nai river serves water for living, production, irrigation, aquaculture, navigation, and hydropower. It receives a huge impact from the natural and artificial elements, such as municipal wastewater from residential areas and urban centers; industrial wastewater from industrial zones, toxic wastewater from agricultural activities, etc [4, 6, 7, 12]. Therefore, the prediction of water quality change and the capacity of receiving wastewater are very essential in environmental protection for Dong Nai river. The study results showed that the water quality of Dong Nai river is currently achieved to the standard requirement and the using purposes. However, there were some sections where had locally polluted signs and had not be used (such as Dong Nai river in the section 3). Predictably up to 2020, pollutant load will increases, however, the water quality of Dong Nai river is still achieving the fundamental purpose of water supply, except TSS which, water from the area below Tri An damp to Dong Nai bridge, is not reached the regulation permit in the beginning and ending of rainy season. To protect the water of Dong Nai River, the optimal solution is necessary to collect and treat all wastewater from industrial, domestic, livestock and medical activities to get the standard permission before discharged into Dong Nai river. At the same time, considering the capacity of receiving wastewater on the each section of Dong Nai river is conducted to allow new investment projects and license of wastewater dischargement.
ESTABLISHMENT OF MRV PROCEDURES FOR NAMAS DEVELOPMENT IN THE STEEL INDUSTRY
Authors: Anh Tuyet Nguyen Thi
Published: April 2018

In Vietnam, the Monitoring, Reporting and Verification (MRV) of greenhouse gas emissions and procedures that is required to establish a baseline scenario that meets the requirement of a Nationally Appropriate Mitigation Action (NAMA) framework. The steel industry has a strong commercial incentive to monitor its energy use, as energy costs are a key driver for commercial success. In this study, the key question that needs to be examined is whether this data is made available to regulators under existing reporting requirements. If not, the related reasons have to be understood. On the basis of our findings, recommendations need to focus on strengthening reporting incentives, provision of more detailed reporting requirements, and protection of confidentiality. One more key question that needs to be addressed in this context is to which extent there is a gap between Ministry of Industry and Trade’s current and required capabilities in relation to the above functionalities. A number of NAMA readiness activities will be identified and subsequently implemented.
INVESTIGATE THE EFFICIENCY OF RECOVERY OF RECYCLABLES FROM HOUSEHOLD WASTES IN DAU TIENG TOWN, DAU TIENG DISTRICT, BINH DUONG PROVINCE
Authors: Ngoc Thuy Dang Thi
Published: April 2018

The purpose of this paper is to present some results of an investigation of the efficiency of recovery of recyclables from household wastes in Dau Tieng town, Dau Tieng district, Binh Duong. Main methods used in the study are solid waste analysis, sociological investigation and estimation. Interviewed participants include households, scrap purchasing enterprises, scrap buyers (individuals) and solid waste collection employees. The result shows the efficiency of recovery of recyclables from household wastes in Dau Tieng town is quite high with 77.99 %. The major component of the recyclables consists of plastic, glass, paper, aluminum, iron and steel. The amount of recyclable materials lost in the recovery process in studying area is 258.52 kg/day, equivalent to 1,310,696 VND each day.
APPLICATION OF ACID MODIFIED RED MUD FOR LEAD ION REMOVAL FROM AQUEOUS SOLUTION
Authors: Trang Pham Thu
Published: April 2018

In this study, the Pb(II) adsorption experiments with the single acid modified red mud were conducted as a function of initial pH, adsorbent doses, contact time, initial Pb(II) concentrations, and competitive ions. The adsorption results pointed that the highest Pb(II) removal efficiency was achieved at the initial pH 4.0, adsorbent dose 7.5 g/L, shaking speed 150 rpm and contact time around 60 minutes at the room temperature. The adsorption results arrowed that the Pb(II) removal efficiency of the modified red mud was enhanced to 150% compared to the raw red mud. The adsorption capacity of the modified red was measured of 9.52 mg/g, higher compared to several previous studies using the same method and type of acid. The study also indicated that the Pb(II) adsorption kinetic and isotherm were best described by the Pseudo - second - order kinetic and fitted to linearly transform both Langmuir and Freundlich with correlation coefficient (R2) over 0.99. The data obtained in this study indicated that modified red mud by using acid can be used as an effective and low cost adsorbent for heavy metals removal from wastewater.
DISTRIBUTION OF HEAVY METALS IN SURFACE WATER, SUSPENDED PARTICULATE MATTER, SEDIMENT AND CLAM (MERETRIX LYRATA) FROM DOWNSTREAM OF SAIGON-DONG NAI RIVER, VIETNAM
Authors: Viet Tran Tuan
Published: April 2018

This study aimed to evaluate distribution of selected heavy metals (Cu, Zn, Pb, Cr and Cd) in clams Meretrixlyrata (clam), suspended particulate matter (SPM), water and sediment in the downstream area of Saigon – Dong Nai (SG-DN) River. During March to September 2015, the contamination of those metals at four sampling sites from fresh water to brackish water zone and Meretrix Lyrata clams, which were cultured at many clam farms at Can Thanh beach at Can Gio District, were monitored. The concentrations of metals in clam samples were also determined at a comparative sampling site at Tan Thanh beach (Tien Giang province). Generally, the order of metal concentrations in all environmental components along the SG-DN River was Zn>Cu>Cr>Pb>Cd while the metal concentrations in different environmental components at Can Thanh area were in different orders. According to the results, the increasing tendency of only Cu, Zn and Cd concentrations in SPM and sediment from river upstream to estuary were found. All trace metal concentrations in clam samples were higher than in water and smaller than in sediment and SPM at Can Thanh. Only Cr concentrations in medium and small clam samples had positive significant correlations with those in sediment and SPM (medium size only). In comparison with concentrations of trace metals in water, sediment, SPM and clams at Tan Thanh, those at Can Thanh were higher.
COMPARISON OF ETHANOL YIELD BETWEEN SEPARATE AND SIMULTANEOUS HYDROLYSIS AND ETHANOL FERMENTATION OF FORMIC- FRACTIONATED SUGARCANE BAGASSE
Authors: Sa Ngo Duy
Published: April 2018

The fractionation of sugarcane bagasse using formic acid allowed removing lignin and hemicellulose, obtaining a material containing up to 90 % cellulose. The material can be easily hydrolyzed into glucose to serve as materials to produce high value added products such as biofuel, chemicals, pharmaceuticals, food additives, and the likes. The hydrolysate of fractionated bagasse was easily fermented with a (ethanol) fermentation yield attained 91.08 ± 2.02 %, showing no significant inhibition to the yeast in the hydrolysate. In this study, a process of simultaneous hydrolysis and fermentation (SSF) was performed to convert fractionated sugarcane bagasse at 20 % consistency to ethanol. The process with 6h pre-hydrolysis at 50 0C then SSF at 37 0C could attain a high ethanol concentration of 82.46 ± 3.42 g/L in the fermentation with the ethanol recovery yield of 81.66±1.88%; which was15.37 ± 1.06 % higher than that of the separate hydrolysis and fermentation (SHF) process (70.78 ± 0.25 %). In addition, in the SSF, the process time was shorten to 4 days instead of 7 days in the SHF.
LAB-SCALE STUDY ON CO-DIGESTION OF KITCHEN WASTE, SLUDGE AND SEWAGE
Authors: Tran Son Minh
Published: April 2018

Anaerobic digestion is widely used for biodegradable solid organic wastes in order to recover bio-energy in the form of biogas. Some previous studies presented that co-digestion of various substrates can improve biogas yields as well as enhanceperformance of organic wastes digestion, in comparison with digestion of sole solid waste. This study aimed to evaluate the performance of anaerobic mono-digestion and anaerobic co-digestion of the following mixtures: (a) sole kitchen waste (KW), (b) KW and sewage (SW), (c) sole sludge (SL)and (d) KW and SL. This study was conductedby four lab-scale anaerobic complete mixing reactors (numbered MH1 – MH4) in 4,5 liters working volume atorganic loading rate (OLR) 2,0 g(VS).L-1.d-1. The KW was collected from canteen B4 and SW was collected from effluent from septic tank C6 Building in Ho Chi Minh University of Technology (HCMUT). The results show that the reactor of sole KW obtained average total chemical oxygen demand (tCOD), soluble chemical oxygen demand (sCOD), total solid (TS), volatile solid (VS), total phosphorus (TP) and total Kjeldahl nitrogen (TKN) of 62 %, 62 %, 71 %, 72 %, 73 % and 45 %, respectively, whereas reactor of KW and SW co-digestion had were tCOD, sCOD, TS, VS, TP and TKN removal of 73 %, 78 %, 75 %, 79 %, 59 % and 57 %, respectively. Thus co-digestion of KW and SW revealed an efficient enhancement of digestion, instead of sole KW digestion. Similarly, TS (74 %) and VS removals (75 %) of co-digesting mixtures of SL and KW were higher than those of sole SL digestion (67 %). Furthermore, co-digestion of SL and KW obtained better performance in tCOD and sCOD removals (70 % and 76 %, respectively).
PARTITION OF POLYCYCLIC AROMATIC HYDROCARBONS IN WATER-SEDIMENT SYSTEM CONTAINING HUMIC ACID
Authors: Anh Van Dieu
Published: April 2018

Natural dissolved organic matter (DOM) in the water environment has the potential to enhance the solubility of PAHs into the water phase, resulting in strong influence on their environmental fate. In this study, Nordic aquatic humic acid (HA) was used as a DOM. The effect of HA on the partition behaviour of PAHs in the sediment water system was examined by comparing the partition of three PAHs: Phenanthrene (Phe), Pyrene (Pyr), and Benzo[a]pyrene (BaP) in the water sediment system. An isotherm partition of PAHs between water and sediment was studied. The presence of HA in the sediment water system shifted the sediment water  partition of PAHs to the water phase. The more hydrophobic the PAH was, the stronger the effect of HA on Kd was. Observed KDOM fitted well the linear free energy relationship. A three-phase partitioning model was established and successfully described the partition behavior of PAHs in water-sediment system.
APPLICATION OF PRE-OZONATION FOR REMOVAL OF DISINFECTION BY- PRODUCTS PRE-CURSOR FROM SAIGON RIVER WATER
Authors: Thanh Loan Bui Thi
Published: April 2018

This study aimed to apply pre-ozonation for removal of disinfection by-products precursors to reduce the formation of trihalomethanes (THMs) in Saigon river water. The pre-ozonation process was conducted in a lab-scale ozone contactor. The raw water sample was collected from Saigon River at the Hoa Phu pump station in Cu Chi District, Ho Chi Minh City. The suitable condition for pre-ozonation was found. At ozone dose of 1.5 mgO3/mgDOC, pH of 8.5, and contact time of 15 minutes, the removal efficiency of turbidity, color, iron, manganese, dissolved organic carbon (DOC), trihalomethanes formation potential (THMFP) were 36 %, 25 %, 56 %, 81 %, 35 %, and 46 %, respectively. These results indicated that the pre-ozonation could reduce DOC concentration and thus resulted in significant mitigation of THMs formation. In comparison with pre-chlorination, THMFP of raw water pretreated by pre-ozonation was lower. Moreover, this study showed that the pre-ozonation was more effective than pre-chlorination in terms of turbidity, color, manganese, and DOC removals.
THE CULTIVATION OF SPIRULINA PLATENSIS ON VERTICAL AEROPONIC SUBSTRATES
Authors: Lien Nguyen Thi
Published: April 2018

To improve the efficiency of algae production process, most studies have focused on selecting algal strains; controlling nutrient, temperatures and pH as well as biomass processing technologies. However, technical innovations in algae cultivation have remained elusive. For this reason, a new technique in cultivation system was studied to determine if it could produce significant quantities of biomass compared to the traditional hydroponic system. After 8 days at same culture conditions: LED lights on a 24 hours off light cycle, microalgae density (OD560 = 1.4), 40 mL of the inoculum, luminosity 2000 lux and temperature was maintained between 25–26 °C, the algae was harvested and the effluent was collected for measuring dry weight of algal biomass. The vertical substrate system have a greater productivity on the substrate based system than traditional hydroponic system. There was increased up to 1.7 times for biomass dry weight in substrate-grown system compared to aqueous-grown system after 8 days of growth. This vertical substrate system produced significant areal yield of 0.8 g m-2d-1 and the areal growth rate of 9.1 g/ m² respectively.
VARIATIONS IN FATTY ACID COMPOSITION OF TEA LEAVES (CAMELLIA SINENSIS) DUE TO PLUCKING TIME AND CULTIVARS
Authors: Lan Anh Nguyen Thi
Published: April 2018

Fatty acid in green tea leaves is important flavour precursor which has a negative effect onaroma quality of black teas. In this study, fatty acid composition of three cultivars includingShan Chat Tien, Trung Du and PH11 plucked at different time was analyzed by GC-MS/MS.The results showed that C16:0, C18:2, C18:1, C18:0 and C18:3 were the most abundant fattyacids indentified in tea leaves. In particular, total saturated fatty acid in the tea leaves plucked inJune and September was higher than total unsaturated fatty acid and vice versa for sampleplucked in March. Principal component analysis (PCA) showed that fatty acid compositions insamples plucked in June of three cultivars were similar to each other and they were characterizedby C18:0, C22:0 and C20:0. The sample plucked in March and in September were characterizedby C18:1, C18:2 and C18:3, andC18:1, C16:1, C18:0, C14:1 and C14:0; respectively. Thesample plucked in March had the highest total fat content followed by sample plucked inSeptember and June. The results showed that plucking time and cultivars significantlyinfluenced the fatty acid composition of tea leaves.
SOME TRITERPENOIDS AND STEROIDS FROM THE LICHEN LOBARIA ORIENTALIS, LOBARIACEAE.
Authors: My Dung Nguyen Thi
Published: April 2018

Chemical investigation of the ethyl acetate extract of the lichen Lobaria orientalis,Lobariaceae, collected in Vietnam, afforded six known compounds, including four triterpenoids,zeorin (1), 16β-acetoxyhopane-6α,22-diol (2), retigeric acid A (3), retigeric acid B (4), togetherwith two steroids, ergosterol-5α,8α-peroxide (5) and cerevisterol (6). Their chemical structureswere elucidated by spectroscopic data analysis and comparison with those reported in theliterature. The cytotoxic activities of some compounds against liver hepatocellular carcinoma(HepG2), human lung cancer (NCI-H460), human epithelial carcinoma (HeLa) and humanbreast cancer (MCF-7) cell lines were evaluated. Compound 2 exhibited good cytotoxicityagainst MCF-7 cancer cell line with IC50 value of 21.10 μg/mL. This is the first time compounds(1), (2), (6) are reported in the Lobaria genus.
COMPUTATIONAL STUDY OF MOLECULAR STRUCTURES AND ANTIOXIDANT MECHANISM OF OVOTHIOLS
Authors: Le Tien Dung
Published: April 2018

In this paper, the molecular structure and antioxidant activity of ovothiols (OSH) have beenstudied by using four DFT functionals, namely B3LYP, B3PW91, X3LYP, M06 with the basisset of 6-311++G(2df,2p). Two major antioxidant mechanisms, namely, hydrogen atom transfer(HAT) and stepwise electron transfer-proton transfer (SET-PT) have been investigated andapplied on three optimized conformations of ovothiols. Bond dissociation enthalpy (BDE),vertical ionization energy (IE), proton dissociation enthalpy (PDE), chemical potential (μ),chemical hardness (η) and global electrophilicity (ω), have been calculated and discussed in thegas phase.
CHEMICAL CONSTITUENTS FROM THE MYCELIUM OF ISARIA JAPONICA YASUDA
Authors: Tuan Nguyen Ngoc
Published: April 2018

A chemical investigation of the mycelium of Isaria japnonica Yasuda resulted in theidentification of eight compounds, including two steroids (ergosterol, ergosterol peroxide), oneflavonoid (tricine), one phenolic (2-hydroxy-3-phenylpropanoic acid), two nitrogenouscompounds (adenosine, uracil), one saccharide (D-mannitol), one amino acid (3-amino butanoicacid). The chemical structures of nine compounds were determined on the basis of 1D and 2DNMR, UV, IR and MS analytical results.
ĐA DẠNG CỦA NHÓM CÂY CHO DẦU VÀ NHỰA Ở VƯỜN QUỐC GIA PÙ MÁT VÀ HIỆN TRẠNG KHAI THÁC, QUẢN LÍ
Authors: Minh Châu Đào Thị
Published: April 2018

Vườn Quốc Gia Pù Mát có diện tích lớn nhất miền bắc nước ta, với 94.804,4 ha vùng lõi, và86.000 ha vùng đệm, trong đó đến 94% diện tích được che phủ và 22 % diện tích rừng nguyênsinh. Theo kết quả nghiên cứu của chúng tôi, có 136 loài cây rừng cho nhựa, dầu thuộc 96 chi, 43họ thực vật bậc cao trong Vườn Quốc Gia Pù Mát. Có 7 loài thực vật thuộc nhóm này là loài quýhiếm, có tên trong Sách Đỏ Việt nam (2007) và danh lục đỏ của IUCN, chúng vẫn đang bị khaithác quá mức để xuất khẩu trái ngạch sang thị trường Trung Quốc. Hiểu biết của người dân và cánbộ quản lí địa phương về các loài cây cho dầu và nhựa còn rất hạn chế, rất ít quan tâm để việc quảnlí, khai thác bền vững, đó là nguyên nhân chính dẫn đến cạn kiệt nguồn tài nguyên này.
ISOLATION AND STRUCTURE ELUCIDATION OF THREE FLAVONOIDS FROM THE SEED OF ZIZIPHUS MAURITIANA LAM
Authors: Thanh Loan Vũ Thị
Published: April 2018

Three flavonoids, spinosin (1), 6′′′-feruloyl spinosin (2) and 6′′′-sinapoyl spinosin (3) wereisolated from EtOH extract of seed of Ziziphus mauritiana. Their structures were elucidated bythe analysis of their spectroscopic data (ESI-MS,1H-NMR,13C-NMR, DEPT, HSQC và HMBC)and compared with literatures. These compounds were isolated for the first time in Vietnamfrom the seed of Ziziphus mauritiana
THIẾT LẬP CHẤT CHUẨN VÀ ĐỊNH LƯỢNG HUPERZIN A TRONG MỘT SỐ LOÀI HỌ THẠCH TÙNG Ở VIỆT NAM
Authors: Chương Nguyễn Ngọc
Published: April 2018

Huperzin A được phân lập lần đầu tiên từ loài Thạch tùng răng và có tác dụng ức chếacetylcholinesterase. Thiết lập chất chuẩn Huperzin A với độ tinh khiết 99,13 % đã được thực hiệnlà rất cần thiết để làm chất đối chiếu trong kiểm nghiệm đánh giá chất lượng các dược liệu. Quytrình định tính và định lượng bằng phương pháp HPLC được xây dựng và thẩm định đạt yêu cầuđể ứng dụng phân tích hàm lượng huperzin A trong 10 loài thuộc họ Thạch tùng ở Việt Nam.
XÂY DỰNG QUY TRÌNH ĐỊNH LƯỢNG FALCARINDIOL TRONG ĐINH LĂNG (Polyscias fructicosa (L.) Harms)
Authors: Ngọc Đan Nguyễn Thị
Published: April 2018

Mục đích của nghiên cứu này là xây dựng được quy trình định lượng falcarindiol trongdược liệu Đinh lăng. Sử dụng hệ thống sắc kí lỏng hiệu năng cao (HPLC), cột Ascentis C18column (250 mm × 4,6 mm, 5 μm), hệ pha động methanol – nước, tốc độ dòng 1,2 ml/phút và ởbước sóng 205 nm. Quy trình định lượng đã được thẩm định về độ lặp lại và độ đúng phù hợp đểđịnh lượng falcarindiol trong mẫu dược liệu. Hàm lượng falcarindiol trong Đinh lăng được xácđịnh nằm trong 0,00031 %. Quy trình đơn giản, nhanh, ít tốn kém, kết quả có độ lặp lại cao vàđộ đúng đáng tin cậy. Với các ưu điểm trên, quy trình này có thể được áp dụng rộng rãi trongđiều kiện thí nghiệm ở Việt Nam. Kết qủa cũng góp phần xây dựng chỉ tiêu định lượng hoạt chấtfalcarindiol trong Đinh lăng. Ngoài ra còn có thể áp dụng quy trình này để định lượng hoạt chấtfalcarindiol trong các dược liệu khác.
NGHIÊN CỨU THÀNH PHẦN HÓA HỌC PHẦN TRÊN MẶT ĐẤT CÂY BẢY LÁ MỘT HOA (PARIS POLYPHYLLA VAR. CHINENSIS FRANCHET) HỌ TRỌNG LÂU (TRILLIACEAE)
Authors: Duyên Nguyễn Thị
Published: April 2018

Nghiên cứu hóa học phân đoạn n-butanol loài bảy lá một hoa (Paris polyphylla var.chinensis Franchet) đã phân lập được 5 hợp chất là: diosgenin (1), stigmasterol-3-O-β-Dglucopyranosid(2), este glycerol (3), dioscin (4) và paris saponin VII (5). Cấu trúc của các chấtđược xác định thông qua phân tích phổ thực nhiệm: MS và NMR. Đây là báo cáo đầu tiên về cácchất từ phần trên mặt đất bảy lá một hoa được trồng tại Sapa - Lào Cai.
NGHIÊN CỨU QUÁ TRÌNH HÌNH THÀNH VÀ HÌNH THÁI HỌC BỀ MẶT CỦA CÁC MÀNG ĐA LỚP CHỨA POLYSACCHARIDE
Authors: Thu Thủy Đinh Thị
Published: April 2018

Bằng phương pháp kết tủa theo lớp đã thu được màng đơn và đa lớp chứapolyhexamethylguanidine, chitosan, dimethylchitosan và carboxymethylcellulose. Hình thái họccủa các màng phủ này được nghiên cứu với việc sử dụng kính hiển vi nguyên tử (AFM), góc tiếpxúc được xác định bởi phương pháp giọt tĩnh. Đã chỉ ra được khả năng hình thành các màng phủđa lớp chứa các polysaccharide với bề mặt nhẵn đồng nhất và không khiếm khuyết (chỉ số độnhám < 0,5 nm). Đã xác lập được rằng, tất cả các đơn và đa màng có tính háo nước: góc biênthấm ươt < 40 grad.
LIVER INTENSITY DETERMINATION IN THE 3D ABDOMINAL MR IMAGE USING NEURAL NETWORK
Authors: Ngoc Le Trong
Published: April 2018

This study presents an approach to automatically identify the liver range intensity in the 3D abdominal MR images using neural network. The proposed scheme consists of three main stages. First, the T1-weighted MR images of the liver in the portal-venous phase are reduced noise by applying the anisotropic diffusion algorithm. The histogram of the 3D reduced image is determined. The function approximation is applied to the computed histogram by using the neural network. The peaks are computed and the peak corresponding to the liver region is determined. This peak plays an important role for a fully automatic liver segmentation. The another salient point of this proposed approach is that the neural network is trained by an effective algorithm called extreme learning machine, this algorithm can offer a good performance with high learning speed in many applications.