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Pervasiveness of microplastics in the gastrointestinal tract of some selected fish species from Turag River alongside the capital city of Bangladesh

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Emerging Contaminants 2024年第3期10卷 77-85页

作者： hm Shahnewaz Khan Jabed Hasan Mohammed Manik Murad Ahmed Farukh Md Shahjahan Department of Environmental Science Bangladesh Agricultural UniversityMymensingh2202Bangladesh Laboratory of Fish Ecophysiology Department of Fisheries ManagementBangladesh Agricultural UniversityMymensingh2202Bangladesh

Microplastics(MPs)are synthetic contaminants that have received global attention due to their ubiquitous occurrence,extreme durability,and capacity to harm ecosystems and human *** study investigated the occurrence of MPs in three fish species(Channa striata,Puntius sophore and Anabas testudineus)collected from two locations(Ashulia Bridge and Mirpur Road)of the Turag River,which flows alongside the Dhaka city,*** abundance(items/individuals)was highest in Channa striata(3.8±0.6)from the Ashulia Bridge area and lowest in Puntius sophore(1.8±0.4)from the Mirpur Road *** was found to be the most dominant(89e93%)form of MPs followed by fragments(21 e35%),films(0e26%)and foams(0e5%).The dominant color of MPs was blue(69e83%),then red(20 e33%),black(11e14%),green(8e20%),and purple(6e8%).The majority(56e71%)of the MPs assessed were<0.5 mm in size,followed by 0.5e1.0 mm(29e33%)and 1e5 mm(38e53%).ATR-FTIR examination revealed three specific polymer varieties-PP(40%),PS(30%)and LDPE(30%).The results of this study provided a baseline of MPs pollution in one of the major protein sources freshwater fishes and raised concern on public health particularly who consume fishes from the urban waterways.

关键词： Microplastics Polymer Bangladesh Turag river ATR-FTIR

MUSCL TYPE SCHEMES AND DISCRETE ENTROPY CONDITIONS

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维普期刊数据库

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Journal of Computational Mathematics 1997年第1期15卷 72-80页

作者： Zhao, N Wu, hm NANJING UNIV DEPT AERODYNAMNANJING 210008PEOPLES R CHINA CHINESE ACAD SCI STATE KEY LAB SCI & ENGN COMPICMSECBEIJINGPEOPLES R CHINA

In this paper, the semi-discrete entropy conditions with so called the proper discrete entropy flux of a class of high resolution MUSCL type schemes are discussed for genuinely nonlinear scalar conservation laws. It is shown that the high resolution schemes satisfying such;semi-discrete entropy conditions cannot preserve second order accuracy in the rarefaction region.

关键词： Computational fluid dynamics Convergence of numerical methods Nonlinear equations Numerical methods

SELECTIVE　REDUCTION　OF　CLERODANE　DITERPENOIDS

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Chinese Chemical Letters 1996年第5期7卷 411-414页

作者： Chen, hm Min, ZD NANKAI UNIV INST ELEMENTOORGAN CHEMTIANJIN 300071PEOPLES R CHINA CHINA PHARMACEUT UNIV DEPT PHYTOCHEMNANJING 210008PEOPLES R CHINA

Abstract: The α,β-unsaturated γ-lactones of neo-clerodane diterpenoids teucvidin, teupernin E and ajugacumbin A were selectively transformed into saturated γ-lactones and unsaturated diol derivatives with NaBH4. These transformations are of interest due to their selective reduction as compared with catalytic hydrogenation and LiAlH4 reduction of these diterpenoid compounds.

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ELASTIC WAVES IN 3-D DISCRETE GRIDS

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Acta Mechanica Solida Sinica 1995年第4期8卷 283-293页

作者： Guan, hm Liao, ZP INST ENGN MECH HARBIN 150080PEOPLES R CHINA

Wave motion in finite element models presents some characteristics different from those of wave motion in continuum, which leads to the errors and other special phenomena in finite element simulation of wave motion. The wave propagation in a 3-D finite element model is studied by utilizing the formal solution in the paper, and the corresponding dispersion relations are derived. Then the main properties of wave motion in 3-D grids such as dispersion, cut-off frequency and polarization drift are discussed. Characteristics different from those of wave motion in 2-D grids are revealed.

关键词： finite elements discrete grids 3-dimensional wave motion

Ab initio Study on the Molecular Geometry, Electronic Structure and Thermodynamic Properties of Benzotrifuroxan(BTF)

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Chinese Journal of Structural Chemistry 1999年第2期18卷 49-55页

作者： Gong, XD Xiao, hm Dong, HS Nanjing Univ Sci & Technol Dept Chem Nanjing 210094 Peoples R China China Acad Engn Phys Inst Chem Mat Mianyang 610003 Peoples R China

The molecular geometries and electronic structures of two isomers of benzotrifuroxan (BTF) have been studied using ab initio molecular orbital method at the HF/6 31G * level. The calculated results show that the hexanitroso isomer has much higher energy than the tetracyclic form and is unstable. Infrared frequencies have been calculated for the stable tetracyclic structure and scaled by 0.89. The scaled frequencies agree well with the available experimental results, and have been used to derive the standard thermodynamic functions, heat capacity( Cp °), entropy( S °) and enthalpy( H° H 298 °).

关键词： benzotrifuroxan(BTF) ab initio MO method molecular geometry electronic structure IR frequency thermodynamic property

A Whitecap Coverage Model Based on the Surface Slope For Criterion of Wave Breaking

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China Ocean Engineering 1998年第1期13卷 73-85页

作者： Xu, DL Yu, DY Lu, hm Ocean Univ Qindao Phys Oceanog Lab Qingdao 266003 Peoples R China Ocean Univ Qindao Sch Engn Qingdao 266003 Peoples R China

Using the limit surface slope as a criterion of wave breaking, a simple model for estimating the spatial fraction of breaking surface of sea at an instant, which is regarded as the whitecap coverge in this paper, is analytically derived from the probability density of surface slope based on Gaussian statistics. The resulting fraction is found depending on the fourth moment of wave spectum, m(4), as well as the critical threshold of surface slope. By expressing the fourth moment in terms of the Neumann spectrum, a formula linking the fraction and wind speed for fully developed sea states is obtianed. Another formula relating the fraction to both wind speed and fetch (or duration) is achieved by expressing m, in terms of the Krylov spectrum and applying the empirical relationships used in the SMB ocean wave predicting technique. A comparison between these results and the field data of whitecap coverage collected by Monahan and O'Muircheartuigh shows an encouraging agreement.

关键词： whitecap coverage criterion of wave breaking wind speed wind fetch wind duration fully developed sea state fetch-limited sea state

Proton transfer across conducting polypyrrole membrane separated by two electrolyte solutions

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Chinese Journal of Chemistry 1997年第5期15卷 410-416页

作者： Wang, hm Yu, ZM Wang, EK Chinese Acad Sci Changchun Inst Appl Chem Electroanalyt Chem Lab Changchun 130022 Jilin Peoples R China

Electrochemical behavior of the transfer of H+ across polypyrrole membrane (PPM) was studied. The transfer process was quasi-reversible and mainly diffusion-controlled. PPM electropolymerized in water solution has better reversibility than that in CH3CN solution for the transfer of H+. The transfer process of H+ across the two kinds of PPM indicated that the PPM electrochemically polymerized was of asymmetry.

关键词： polypyrrole membrane proton transfer electrochemical polymerization

Spectral Characteristics of Wind-Waves in Laboratory

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China Ocean Engineering 1998年第2期13卷 183-190页

作者： Lu, hm Xu, DL Yu, DY Ocean Univ Qingdao Phys Oceanog Lab Qingdao 266003 Peoples R China Ocean Univ Qingdao Coll Engn Qingdao 266003 Peoples R China

Spectral characteristics of wind-generated waves in labortaory are presented on the basis of a systematic measurement in a large-scale wind-wave channel and compared with those in the field. A marked characteristics of the measured spetra is the existence of secondary spectrum-peak. The dependence of spectral peak-frequency, peak-value and zeroth-order moment on wind speed and fetch are presented and found roughly similar to those in the field represented by the JONSWAP spectrum, regardless of the differences in coefficient. The spectral slope beta at high-frequencies are found somewhat greater than those of field wind-waves in both cases of deep and shallow waters. Except for the low-frequency part, the spectral forms measured in different wind conditions are similar and fit for the JONSWAP spectrum with gamma = 6 and beta = 5.5. Some relevant problems are discussed.

关键词： wind-wave channel spectral characteristics JONSWAP spectrum

Studies on monodispersed colloidal particles of doped yttrium compounds

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Chinese Journal of Chemistry 1995年第3期13卷 199-206页

作者： DENG, hm XU, Y GU, YD FUDAN UNIV ANAL & MEASUREMENT RES CTRSHANGHAI 200433PEOPLES R CHINA FUDAN UNIV DEPT CHEMSHANGHAI 200433PEOPLES R CHINA

Monodispersed particles of doped yttrium basic carbonates were prepared at aging at elevated temperature corresponding salts solutions in the presence of urea. Coprecipitation in mixed solutions of yttrium, lanthanum and neodymium salts under similar experimental conditions yielded composite particles of basic carbonates. The content of the three metals in the solids followed closely the initial composition of the reacting solutions. On calcination all prepared solids converted to their corresponding oxides while retaining their particle morphology. The so-prepared powders were characterized by various techniques.

关键词： YTTRIUM COMPOUNDS MONODISPERSED PARTICLES UREA DECOMPOSITION