检索结果-南通市图书馆

Long-Term Trends and Its Best Functional Form Estimation of Yearly Maximum and Minimum Temperatures at Cotonou City by Improved Complete Ensemble Empirical Mode Decomposition with Adaptive noise Method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Atmospheric and Climate Sciences 2022年第1期12卷 31-42页

作者： Médard noukpo Agbazo Joseph Adébiyi Adéchinan gabin koto n’gobi Joseph Bessou International Chair in Mathematical Physics and Applications (CIPMA-Chair Unesco) Université d’Abomey-Calavi UAC Cotonou Bénin Laboratoire de Physique du Rayonnement (LPR) Faculté des Sciences et Techniques Université d’Abomey-Calavi UAC Cotonou Bénin Département de Physique Faculté des Sciences et Techniques Université Nationale des Sciences Technologies Ingénierie et Mathématiques (UNSTIM) Abomey Bénin Agence nationale de la Météorologie du Bénin Meteo Bénin

The understanding of the long-term trend in climatic variables is necessary for the climate change impacts studies and for modeling several processes in environmental engineering. However, for climatic variables, long-term trend is usually unknown whether there is a trend component and, if so, the functional form of this trend is also unknown. In this context, a conventional strategy consists to assume randomly the shape of the local trends in the time series. For example, the polynomial forms with random order are arbitrarily chosen as the shape of the trend without any previous justification. This study aims to 1) estimate the real long-term nonlinear trend and the changing rate of the yearly high temperature among the daily minimum (YHTaDMinT) and maximum temperatures (YHTaDMaxT) observed at Cotonou city, n>2) find out for these real trend and trend increment, the best polynomial trend model among four trend models (linear, quadratic, third-order and fourth-order polynomial function). For both time series, the results show that YHTaDMinT and YHTaDMaxT time series are characterized by nonlinear and monotonically increasing trend. The trend increments present differenn style="font-family:Verdana;">t phases in their nonmonotone variations. Among the four trend estimations models, the trend obtained by third-order and fourth-order polynomial functions exhibits a close pattern with the real long-term nonlinear trend given by the Improved Complete Ensemble Empirical Mode Decomposition with Adaptive noise (ICEEMDAn). But, the fourth-order polynomial function is optimal, therefore, it can be used as the funct

关键词： Long-Term Trends Polynomial Trend Models Trend Increment ICEEMDAn Extrema Temperature

Analysis and Predictability of Dry Spell Lengths Observed in Synoptic Stations of Benin Republic (West Africa)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

American Journal of Climate Change 2021年第4期10卷 597-618页

作者： Médard noukpo Agbazo Joseph Adébiyi Adéchinan gabin koto n'gobi Joseph Bessou International Chair in Mathematical Physics and Applications (ICMPA-UnESCO Chair) Université d’Abomey-Calavi Abomey-Calavi Bénin Laboratoire de Physique du Rayonnement (LPR) Université d’Abomey-Calavi Abomey-Calavi Bénin Département de Physique Faculté des Sciences et Techniques Université Nationale des Sciences Technologies Ingénierie et Mathématiques (UNSTIM) Abomey Bénin Agence nationale de la Météorologie du Bénin (METEO BEnIn) Cotonou Bénin

The complex behavior and predictability of the Dry Spell Lengths (DSL) series obtained in Benin synoptic stations, from 1951 to 2010 are analyzed in this paper using a fractal approach. The synoptic stations are located in Cotonou, Bohicon, Save (subequatorial climate), and Parakou, natitingou, Kandi (Sudanian climate). The DSLs are computed by considering four thresholds level, R0 = {1.0, 1.5, 2.0 and 5.0} mm/day. The fractal trace is estimated for dry spell density by the mean of the “Dry Spell Spell” (DSS) n-index. The rescaled range method is used to determine the predictability of DSL. By analyzing the DSS, results show that low DSS n-index values (n-index n the northern part of Benin than in the southern region, whereas, high values of DSS n-index (n-index > 0.4) occur preferentially in the southern part. Therefore, during 1951-2010, the Sudanian region presents frequent wet spells, alternated with short dry spells than in the subequatorial one. However, a high degree of long dry spell persistence, followed by short dry events is observed in the subequatorial region than in the Sudanian one. The longest DSL is observed in the subequatorial region, especially in Cotonou. Except for the Kandi station, the DSLs series obtained at synoptic stations are characterized by persistence. Therefore, autoregressive processes could be applied to the DSL series. Generally, the physical process governing dry spells observed at Save, natitingou, and Bohicon are consistently predictable than the process governing the stations of the Cotonou and Parakou. However, at Kandi station, the DSL process approximates the usual Brownian motion, and it is, therefore, unpredictable or difficult to predict.

关键词： Hurst Exponent n-Index DSL Predictability Complex Behavior Benin

Evaluation of Particle Properties of MgO/TiO₂ Material by Monte Carlo Simulation Method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science and Chemical Engineering 2024年第2期12卷 49-60页

作者： Koffi n’guessan Placide gabin Allangba Yves Kily Hervé Fagnidi Hermann n’guessan Zié Traoré Koffi Arnaud Kamenan Physics Pedagogical Unit Laboratory of Environmental Science and Technology University Jean Lorougnon Guédé Daloa C&#244te d’Ivoire Laboratory of Fundamental and Applied Physics University Nangui Abrogoua Abidjan C&#244te d’Ivoire Department of Medical Physics University of Trieste and International Centre for Theoretical Physics (ICTP) Trieste Italy Department of Science and Technology University Alassane Ouattara Bouaké C&#244te d’Ivoire nuclear Physics and Radiation Protection Team Laboratory of Material Sciences Environment and Solar Energy University Felix Houphouet-Boigny Abidjan C&#244te d’Ivoire Department of Mathematics Physics and Chemistry UFR Biological Sciences University Peleforo Gon Coulibaly Korhogo C&#244te d’Ivoire

The simulation by the Monte Carlo method executed by the software PyPEnELOPE proved effective to specify the particle propagation characteristics by calculating the absorption fractions, backscattering and transmission of electrons and secondary photons under the incidence of 0.5 to 20 KeV range of primary electrons. More than 99.9% of the primary electrons were transmitted in the 125 nm thick MgO/TiO2 material at 20 KeV. This occurred because several interactions took place in the transmitted primary irradiation such as characteristic, fluorescence, and bremsstrahlung produced when of the occupation of the KL3, KL2, KM3, and KM2 shell and sub-shell of titanium and magnesium which are the elements with a high atomic number in the material. The transmission particle characteristic of this material is therefore an indicator capable of improving the electrical performance and properties of the sensor.

关键词： Monte Carlo PyPEnELOPE Primary Electrons Transmission MgO/TiO2

Anti-inflammatory and antipyretic properties of Kang 601 heji,a traditional Chinese oral liquid dosage form

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Biomedicine 2015年第11期5卷 921-927页

作者： Raphael nammahime Alolga Sarah Wambui Amadi Vitus Onoja Assogba gabin Assanhou Moses Muyaba Said Abasse Kassim State Key Laboratory of natural Medicines China Pharmaceutical University Department of Pharmacology China Pharmaceutical University Joint Key Laboratory for Drug Development Department of PharmaceuticsChina Pharmaceutical University Department of Medicinal Chemistry China Pharmaceutical University

Objective: To evaluate the scientific basis for the use of Kang 601 heji(K-601) as an anti-in flammatory and antipyretic agent using appropriate animal ***: Carrageenan-induced rat paw and xylene-induced ear oedemas were models used to investigate anti-in flammatory actions of K-601. Lipopolysaccharide-induced pyrexia model was used to evaluate antipyretic activity in Wistar rats. The antiin flammatory and antipyretic mechanisms were evaluated by detecting prostaglandins E2, nitric oxide, interleukin-1b and tumour necrosis factora levels using appropriate reagents and ELISA ***: The results revealed that K-601 reduced the level of in flammations in both antiin flammatory models in a dose-dependent manner. The same was true for the antipyretic model. The possible mechanisms of actions were through the inhibition of prostaglandins E2, interleukin-1b, tumour necrosis factora and nitric ***: K-601 has proven anti-in flammatory and antipyretic actions. The findings provide a scientific basis for the use of K-601 as anti-in flammatory and antipyretic agent in traditional Chinese medicinal practice.

关键词： Kang 601 heji Anti-in flammatory Antipyretic Model

The Intensification of Sino-African Economic Cooperation： What Is the Role of the Congolese Economy in the Game of Equality and Mutual Benefit？

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Modern Accounting and Auditing 2012年第10期8卷 1541-1559页

作者： gabin Merlin Gambou Paulin Houanye Zhao Zhongxiu University of International Business and Economics Beijing China

The main goal of this paper is to examine the economic relations of the Republic of Congo in its bilateral cooperation with China and to see its real implications in the Congolese economy. In other words, this paper is going to highlight the real status of the Republic of Congo in the recent intensification of cooperation with the Middle Kingdom. Indeed, China has always been criticized as a predator of African raw materials by its opponents （traditional partners of Africa）. Thus, in the Congolese context, the authors try to analyze and see whether this cooperation has corroborated that anti-thesis or not. After examining various facets of Chinese interventions in Congo, the authors conclude that： The cooperation between these two countries is a kind of cooperation for the modernization and industrialization of the Congo, which is now developing in a satisfactory way. It brings real benefits to people of both countries, and it is also welcomed by both of them. Congo and China are bound by a traditional friendship, they have cooperated with each other since 1964, and both countries must be determined to further strengthen this cooperation to achieve a common development. It should also be noted that China is first and foremost a strategic partner of development for the Congo because of the positive results recorded by its actions in different areas of its operations in that country. The authors have also noted some pitfalls and have made some suggestions accordingly, in order to enhance the performance of cooperation between the two countries. It is particularly in terms of the transfer of technology, compliance with the regulations in force in Congo by Chinese enterprises, the adjustments made by China concerning the training of Congolese students who receive scholarships from the Chinese government for their training in China and on Chinese language, and finally the area of diversification of production, it is worth pointing out that the Congo only exports its main

关键词： Sino-Africa trade economic cooperation Congolese and Chinese economic presence in Africa

Thermal Properties of Earth Bricks Stabilised with Cement and Sawdust Residue Using the Asymmetrical Hot-Plane Method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Applied Sciences 2023年第11期13卷 1910-1934页

作者： gabin Alex nouemssi Guy Edgar ntamack Martin ndibi Mbozo’O Bonaventure Djeumako Ecole nationale Supérieure des Sciences Agros Industrielles Laboratoire de Mécanique Matériaux et Photonique University of Ngaoundéré Ngaoundéré Cameroon Département de Physique/EGCIM Faculté des Sciences et Physique Université de Ngaoundéré Ngaoundéré Cameroon Ecole nationale Supérieure des Sciences Agros Industrielles Département de Génie Mécanique et Productique University of Ngaoundéré Ngaoundéré Cameroon

This paper presents an experimental study of the characterisation of local materials used in the construction and thermal insulation of buildings. These materials are compressed earth bricks stabilised with cement and sawdust. The thermal conductivity, diffusivity, effusivity, and specific heat of earth-based materials containing cement or sawdust have been determined. The results show that the blocks with earth + sawdust are better thermal insulators than the blocks with simple earth. We observe an improvement in thermal efficiency depending on the presence of sawdust or cement stabilisers. For cement stabilisation, the thermal conductivity increases (λ: 1.04 to 1.36 W·m-1·K-1), the diffusivity increases (from 4.32 × 10-7 to 9.82 × 10-7 m2·s-1), and the effusivity decreases (1404 - 1096 J·m-2·K-1·s-1/2). For sawdust stabilisation, the thermal conductivity decreases (λ: 1.04 to 0.64 W·m-1·K-1), the diffusivity increases (from 4.32 × 10-7 to 5.9 × 10-7 m2·s-1), and the effusivity decreases (1404 - 906 J·m-2·K-1·s-1/2). Improving the structural and thermal efficiency of BTC via stabilisation with derived binders or cement is beneficial for the load-bearing capacity and thermal performance of buildings.

关键词： Clay Brick West Cameroon Thermal Conductivity Asymmetric Hot Surface Thermal Properties

Simultaneous Determination by HPLC-UV Vis of Tartrazine and Sunset Yellow in Soft Drinks Sold in Benin

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

American Journal of Analytical Chemistry 2022年第8期13卷 277-288页

作者： Janvier Engelbert Agbokponto André Philippe S. Kpaibe Loconon Achille Yemoa Assogba gabin Assanhou Habib Ganfon Gildas Komenan Gbassi Michèle Aké n’cho Christoph Amin Laboratoire de Chimie Analytique et d’Analyse des Médicaments UFR Pharmacie Faculté des Sciences de la Santé Université d’Abomey-Calavi Cotonou Bénin UFR Pharmacie Faculté des Sciences de la Santé Université d’Abomey-Calavi Cotonou Bénin Département de Chimie Analytique Bromatologie Chimie Générale et Minérale UFR des Sciences Pharmaceutiques et Biologiques Université Félix Houphou&euml t-Boigny Abidjan C&ocirc te d’Ivoire

The use of dyes such as tartrazine (E102) and sunset yellow (E102) in food, beverages and health products for technological and commercial purposes is common. The adverse effects caused by these dyes, such as allergies and hyperactivity disorder have been reported, especially in children. In the present study, a chromatographic method was developed and validated for simultaneous determination of tartrazine and sunset yellow. The chromatographic separation was performed on a Lichrocart® C18 column (125 × 4.6 mm;5 μm) with a security Guard-C18 column (4 × 2.0 mm, 5 μm;Phenomenex, Torrance, CA, USA) maintained at 30°C. The mobile phase consisted of a mixture of acetonitrile/ammonium acetate buffer pH 6.8 in gradient mode with a flow rate of 1 mL/min. The injection volume was 10 μL. The detection wavelength was set at 455 nm. The parameters of specificity, linearity, precision, repeatability, accuracy and sensitivity were examined for validation. The developed method is linear in the range of 1 μg/mL to 100 μg/mL with a R2> 0.998. The intra-day and inter-day precisions (RSD) were less than 0.6% and 3.1% respectively. The detection limit was 0.03 μg/mL and the quantification limit was 0.1 μg/mL. The retention time of tartrazine was 2.86 min, while sunset yellow was detected at 5.67 min. A simple, rapid, accurate and robust HPLC/UV-Visible method was developed and validated for simultaneous identification and quantification of tartrazine and sunset yellow. This developed method was successfully applied for the simultaneous determination of tartrazine and sunset yellow in soft drinks sold in Benin.

关键词： Tartrazine Sunset Yellow HPLC-UV Food Dyes

Physico-Mechanical Characteristics of Earth Bricks Stabilized with Cement and Padouk Sawdust Residues

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Applied Sciences 2024年第7期14卷 1788-1806页

作者： gabin Alex nouemssi Bennis Amine Martin ndibi Mbozo’O Bonaventure Djeumako Doko K. Valery Guy Edgar ntamack LA2MP: Laboratory of Mechanics Materials and Photonics National School of Agro-Industrial Sciences ENSAI Ngaoundr Cameroun Department of Mechanical and Production Engineering National School of Agro-Industrial Sciences ENSAI Ngaoundr Cameroun LMTM: Laboratory of Mechanics Materials and Thermal National School of Mineral Industry ENIM Rabat Morocco LEMA: Laboratory of Energertic and Applied Mechanics University of Abomey-Calavi Cotonou Benin GMMA: Group of Mechanics Materials and Acoustics Department of Physics Faculty of Sciences-EGCIM Ngaoundr Cameroun

The objective of this work is to improve the physical and mechanical properties of stabilized earth blocks (BTC) used in construction in the ndé department of Cameroon. To achieve this, two stabilizers, cement and sawdust, were used at varying percentages of 0%, 4%, 6%, and 8%. Physical characterization tests, including natural water content, specific weight, jar test, Protor, and Atterberg limits, were conducted. Additionally, mechanical tests, such as compression and three-point bending, were performed. The results show that as the amount of stabilizer increases, the density of BTC decreases. The samples with 8% sawdust have the highest density, while those without stabilizers have the lowest. Porosity decreases as sawdust and cement content increases, with smaller values observed in samples with 8% sawdust or cement. Our tests indicate that blocks stabilized with cement have slightly higher compressive strength than those stabilized with sawdust. However, the water absorption rate increases with higher sawdust content.

关键词： Earth block Cement Sawdust Physico-mechanical Characteristics Bangante West Cameroon

Quality Control of Paracetamol Generic Tablets Marketed in Benin and Search of Its Two Impurities P-Aminophenol and P-nitrophenol by HPLC-UV/Visible

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

American Journal of Analytical Chemistry 2022年第11期13卷 449-460页

作者： Yemoa Loconon Achille Agbokponto Janvier Engelbert Assanhou Assogba gabin Adetona Pauline Doffon Parfait Ganfon Habib Roland Marini Djang’eing’a Laboratoire de Chimie analytique et Analyse des Médicaments Unité de Formation et de Recherche en Pharmacie Faculté des Sciences de la Santé. Université d’Abomey Calavi Cotonou Bénin Laboratoire de Pharmacie Galénique et de Technologie Pharmaceutique Unité de Formation et de Recherche en Pharmacie Faculté des Sciences de la Santé Université d’Abomey Calavi Cotonou Bénin Laboratoire de Pharmacognosie et de de Phytothérapie Unité de Formation et de Recherche en Pharmacie Faculté des Sciences de la Santé Université d’Abomey Calavi Cotonou Bénin Laboratoire de Chimie Analytique Pharmaceutique Departement de Pharmacie Université de Liège (ULiège) Liège Belgium

In this work, we evaluated the quality of paracetamol generic tablets while seeking its two main impurities namely 4-para-aminophenol (4-AP) and 4-para-nitrophenol (4-nP) which have nephrotoxic and teratogenic properties. ninety-four (94) samples were collected at various levels of the medicine supply chain and illegal markets in Benin for quality control tests such as visual inspection, pharmacotechnical tests as mass variation, disintegration test, dissolution test, followed by HPLC UV-Vis identification and assay of paracetamol, 4-AP and 4-nP. The analytes were separated on C18 Lichrocart column (250 mm × 4.0 mm i.d, 5 μm);the mobile phase was MeOH:10 mM ammonium acetate buffer pH 6.8 (35:65) pumped at a flow rate of 1 ml/min. The detection was done at 245 nm. Analysis of our results shows that 77.7% of the samples did not comply with the visual inspection test requirements, 2.1% did not pass the mass variation test, 24.3% of the sample batches didn’t comply with the disintegration test requirements. In addition none of these uncomply batches passed the dissolution test, even if the identification test indicated that all samples contained paracetamol. none contained 4-nP (acceptance limit ntained 4-AP but within acceptance limit (4-AP ns of the pharmacopoeias taken as reference (90% - 110%;USP). Further, broader studies should be conducted according to the same rules of good practice for a more comprehensive analysis of the situation. Generally the quality control of paracetamol in most African countries, particularly in Benin, is based on pharmacotechnical tests and paracetamol assay. This work, in addition to the usual tests, showed the importance to search for paracetamol and other drugs’ impurities during their routine quality control.

关键词： Quality Control Substandard Medicines Paracetamol P-Aminophenol P-nitrophenol Benin