Nexus between CO2 Emissions and Economic Growth, Industrial Production, and Foreign Direct Investment in Vietnam: Symmetric ARDL Approach

Vietnam’s economy has been developing strongly in recent years;however, it is necessary to examine the impact of its economic activities on environmental quality. This study aims to evaluate the relationship between CO2 emissions and economic growth, industrial production, and foreign direct investment (FDI) in Vietnam. The ARDL estimation was used to process the dataset from World Bank. Results showed that economic growth, industrial production, and FDI have an impact on CO2 emissions in the long run in Vietnam. Granger Causality test also indicated that there is a causal relationship between economic growth, industrial production, and CO2 emissions in Vietnam from 1990 to 2018, at 5% statistical significance level. Proposed solutions to reduce CO2 emissions but still promote economic growth toward the green growth orientation and zero carbon target attainment are as follows: 1) reduce the use of fossil energy in industrial manufacturing and replace it by renewable energy sources;2) use modern technology for all production sectors in economy;and 3) develop a legal framework for FDI projects selection and choose foreign investors with modern and low carbon emission technology.

Effects of Silicon-Based Fertilizer on Growth, Yield and Nutrient Uptake of Rice in Tropical Zone of Vietnam

Application of silicon(Si) could greatly boost rice yield and mitigate abiotic stress,especially drought.A field experiment was conducted during 2015 at the research farm of Hong Duc University,Thanh Hoa City,Vietnam,to evaluate the effects of five different combined doses of standard fertilizer practice and Si fertilizer on growth,yield and yield components,as well as nutrient uptake of rice.The treatments consisted of the recommended dose of fertilizer(RDF,110 kg/hm^2 N + 90 kg/hm^2 P_2O_5 + 80 kg/hm^2 K_2O) as the control,RDF + 100 kg/hm^2 SiO_2,RDF + 200 kg/hm^2 SiO_2,RDF + 300 kg/hm^2 SiO_2 and RDF + 400 kg/hm^2 SiO_2.The results showed that the growth,grain and straw yields as well as yield components(number of grains per panicle,seed-setting rate and 1000-grain weight) were significantly affected by Si application.The highest grain yield of 3 705 kg/hm^2 was obtained with the highest level of Si fertilizer in combination with RDF(RDF + 400 kg/hm^2 SiO_2),however,it was statistically at par with the yields obtained with RDF + 300 kg/hm^2 SiO_2(3 664 kg/hm^2) and RDF + 200 kg/hm^2 SiO_2(3 621 kg/hm^2).The optimum dose of Si fertilizer with maximized grain yield(3 716 kg/hm^2) was 329 kg/hm^2 SiO_2.The nutrient(Si,N,P and K) uptakes of rice were also significantly enhanced by Si application.Si application at the level of 329 kg/hm^2 along with RDF would help in the sustainable production of rice in the tropical zone of Vietnam.

中国与越南岛屿水产养殖业比较分析

自20世纪80年代以来,全球的岛屿水产养殖业发展迅速,目前全球的水产品增长几乎都来自于水产养殖。本文通对中国与越南岛屿水产养殖业的现状进行比较分析,来探索水产养殖业的可持续发展之路。

Effects of NaOH Concentrations on Properties of the Thermal Power Plant Ashes-Bricks by Alkaline Activation

The use of the thermal power plant ashes including fly ash(FA) and bottom ash(BA) for producing unfired building bricks(UBB) using sodium hydroxide(NaOH) solution as an alkaline activator was investigated. A low applied forming pressure of 0.5 MPa and various NaOH concentrations of 5, 8, 10, and 12 M were used for the preparation of brick samples with different solution-to-binder(S/B) ratios of 0.35 and 0.40. The bricks were subjected to various test programs with reflecting the effect of both NaOH concentrations and S/B ratios on the brick’s properties. The compressive strength, unit weight, ultrasonic pulse velocity, and thermal conductivity of bricks increased with increasing NaOH concentration, whereas the contrary trend was found with increasing S/B ratio. Also, the water absorption of bricks was observed to reduce with increasing NaOH concentration and decreasing S/B ratio. As the results, the combined utilization of both low forming pressure and coal power plant ashes can produce the UBBs with low unit weight, low heat conductivity, and acceptable strength and water absorption rate as stipulated by TCVN 6477-2016. Furthermore, the outcomes of chemical analysis and microstructure observation also demonstrate that a high concentration of the Na OH promoted the geopolymerization process. Notably, the use of NaOH solution of either 10 M or above is recommended for the production of UBBs, which are classified as grade M5.0 or higher.

Local Existence of Solution to a Class of Stochastic Differential Equations with Finite Delay in Hilbert Spaces

In this paper, we present a local Lipchitz condition for the local existence of solution to a class of stochastic differential equations with finite delay in a real separable Hilbert space which has the following form:

Direct Structural Evidences of Epitaxial Growth Ge<SUB>1-X</SUB>Mn<SUB>X</SUB>Nanocolumn Bi-Layers on Ge(001)

Molecular Beam Epitaxy (MBE) system equipped with in-situ Reflection High-Energy Electron Diffraction (RHEED) has been used for (Ge, Mn) thin film growth and monitoring the surface morphology and crystal structure of thin films. Based on the observation of changes in RHEED patterns during nanocolumn growth, we used a real-time control approach to realize multilayer structures that consist of two nanocolumn layers separated by a Ge barrier layer. Transmission Electron Microscopy (TEM) has been used to investigate the structural properties of the GeMn nanocolumns and GeMn/Ge nanocolumns bi-layers samples.

A New Approach for Heavy <i>N</i>-Doping Process in Ge Epilayers Using Specific Solid Source

As an indirect band gap material, Germanium (Ge) has low efficiency of radiative recombination in the wavelength area of about 1550 nm. However, the difference between the direct and indirect band gap is very small (~140 meV) and photoluminescence emission ability of Ge could be greatly enhanced by heavy n-doping process. In this work, Ge growth directly on Si (001) substrate by molecular beam epitaxial (MBE) technique and a high n-doping level in Ge was obtained owning to using GaP decomposition source. The GaP solid source produces P2 molecules instead of P4 molecules, which have higher sticking coefficient than that of P4 comparing to the traditional doping method from PH3 gas precursor molecules. The dependence of optical property on Ge film thickness is also studied. The out-diffusion phenomenon of phosphorus dopant has been observed through SIMS profile analysis. An activated phosphorus concentration can be achieved up to more than 2 × 1019 atoms?cm&minus3 confirmed by Hall effect measurement. This result contributes to realization of Ge-on-Si devices for optoelectronic applications.

Essential Oils Leaf of <i>Cinnamomum glaucescens</i>and <i>Cinnamomum verum</i>from Vietnam

In this paper, compounds identified in the essential oils obtained by hydrodistillation of the leaves of Cinnamomum glaucescens (Nees) Hand.-Mazz and Cinnamomum verum J.S. Presl (Lauraceae family) of Vietnam origin are reported. The chemical analyses were performed using gas chromatography-flame ionisation detector (GC-FID) and gas chromatography coupled with mass spectrometry (GC-MS). The significant compounds of C. glaucescens were geraniol (36.2%) and terpinen-4-ol (19.7%). On the other hand, C. verum comprised of linalool (22.0%) and bicyclogermacrene (11.2%). The present results may represent new chemotypes of the essential oils of C. verum and C. glaucescens.

Critical Parameters and Magnetocaloric Effect of the La_5/8Ca_3/8Mn_0.9750Pd_0.025O₃Compound

The La5/8Ca3/8Mn0.9750Pd0.025O3 compound was studied using DC magnetization measurements. The data were analyzed in the paramagnetic-ferromagnetic phase transition region by the Arrott plot method. The results show the Curie temperature TC ~ 247.8 K and the critical exponents of b = 0.48633, g = 1.18623 and d = 3.431682. The values of the critical exponents are between the mean- field theory and 3D Ising model. The magnetocaloric value is ~5 J/kgK, extracted from the M(H) curves.

Preliminary Study on the Magnetic Properties of GeMn Nanocolumn/Ge Multilayers

Ge0.94Mn0.06 nanocolumn thin film is a unique phase of GeMn diluted magnetic semiconductors (DMS) which exhibit Curie temperature (TC) > 400 K. The multilayers of Ge0.94Mn0.06 nanocolumns separated by nano-scaled spacers represent great interests for spintronic applications, such as spin valves or giant magneto-resistance (GMR) multilayers. In this article, we present the results obtained from the preliminary study on the exchange coupling in two types of GeMn nanocolumn/Ge multilayers. All the samples have been grown using molecular beam epitaxy (MBE). The superconducting quantum interference device (SQUID) magnetometer has been used to determine the magnetic properties of the samples. In the multilayer system Ge/[Ge0.94Mn0.06(40 nm)/Ge(d nm)]9/Ge0.94Mn0.06(40 nm)/Ge, no exchange coupling can be observed. Inversely, exchange coupling between the layers exists and depends on the thickness of the Ge spacers for the GeMn nanocolumns/Ge multilayer spin valve systems. The exchange coupling in the nanocolumns multilayer systems has been shown to be complex due to the leakage field induced by neighboring nanocolumns and the magnetic anisotropy of nanocolumns.

Exponentially Bounded C-semigroup and the Cauchy Initial Value Problems in Complete Random Normed Modules

In this paper,the notion of C-semigroup of continuous module homomorphisms on a complete random normal(RN)module is introduced and investigated.The existence and uniqueness of solution to the Cauchy problem with respect to exponentially bounded C-semigroups of continuous module homomorphisms in a complete RN module are established.