Wyniki wyszukiwania - Biblioteka Nauki

1

Ground sediment transport model and numerical simulation

100%

Sun J.

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2016

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tom 25

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nr 4

EN

Geological disasters caused by city ground subsidence are typical examples of soil failure, which significantly impact urban planning and development. The sediment transport in the soils leads to the increasing porosity of soils, and changes the elastic modulus and Poisson’s ratio, thus the carrying capacity of the soil is reduced and ground subsidence appears. Therefore, the sediment transfer and loss driven by the underground water becomes a key reason for ground subsidence. Studies in this area thus present significant meanings. In this paper, mutual effects between the sediment particles and groundwater seepage are analyzed. We partially fix sediments in soils. Using the numerical simulation, hydraulic pressure is applied to scour so as to study the regular patterns of sediment transport in the soil mass: as time extended, the porosity in soils is gradually enlarged, tending to be stable; as more particles are fixed, porosity is reduced. It is also found that fixed particles, with a part of free sediment particles, form some new fixed sediment structures that hinder the transfer of the free sediment. In addition, parameters like scour time, hydraulic pressure, and the porosity evolution equation relating to the amount of fixed sediment particles are acquired. Findings of this research are expected to provide references for predicting, forecasting, and treating ground subsidence, which is led by sediment transport from the perspective of the soil mass porosity evolution.

2

Stability and support analysis of coverage rock-soil aggregate of longhuguan landslide

63%

Sun J. , Zhou F.

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nr 6

EN

Rock-soil aggregate landslides are distributed all over the world and have done great harm to transportation networks, buildings, personal safety, and city construction. Although landslide studies usually focus on the slope of the single homogeneous material, few slopes are composed of or covered by various complicated geomaterials. This paper proposes a calculation model of the slope covered by rock-soil aggregate and analyzes Longhuguan landslide in Guangxi, China, considering rainfall. Fully considering the weak surface, a support design plan is given.The unbonded cable is taken to support the landslide, the concrete beams are adopted on the angle turning point of the surface, and the slide-resistant piles are used to jointly support the front edge of the slope. Top fissures are blocked and landslide drainage measures are taken. The displacement monitoring proves that the support is effective. This study can provide many references for landslide support and analysis covered by rock-soil aggregate.

3

Netz-Phytoplankton Diversity in the western and Southern regions of the South China Sea

63%

Liu H. , Sun J.

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nr 4

4

Netz-Phytoplankton Diversity in the western and southern regions of the South China Sea

63%

Liu H. , Sun J.

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2015

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tom Vol. 44, No. 4

530--538

EN

Based on the survey records on netz-phytoplankton (>76 μm) collected in the South China Sea (SCS) during the cruise from the 21st August to the 18th October, 2012, the species composition, biodiversity and its spatial distribution were studied. The identified 326 phytoplankton species belonged to 75 genera and 4 phyla. Thalassionema nitzschioides was the most dominant species accounting for 33.24% of the total cell abundance, followed by Bacteriastrum furcatum − 8.69%. Whereas the phytoplankton cell abundance (cells l-1) was the highest in the Zhubi Reef (1106.45 ± 2475.38), the southern SCS (396.84 ± 969.87), the western SCS (90.82 ± 144.66) and the northern SCS (66.48 ± 70.89) in order. The distribution of phytoplankton appears to be affected by the Mekong river discharge and particles derived in Sumatra and Kalimantan from biomass burning, nutrient concentrations, the South China Sea Warm Current (SCSWC). The evaluation of biodiversity indices indicated the high level of species richness, evenness and biodiversity in the survey area.

5

Combined load buckling for cylindrical shells based on a symplectic elasticity approach

51%

Sun J. , Xu X. , Lim C. W.

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tom Vol. 54 nr 3

705--716

EN

Buckling behavior of cylindrical shells subjected to combined pressure, torsion and axial compression is presented by employing a symplectic method. Both symmetric and non- -symmetric boundary conditions are considered. Hamiltonian canonical equations are established by introducing four pairs of dual variables. Then, solution of fundamental equations is converted into a symplectic eigenvalue problem. It is concluded that the influence of pressure on buckling solutions is more significant than that due to compressive load, in particular for a longer external pressured cylindrical shell. Besides, buckling loads and circumferential wavenumbers can be reduced greatly by relaxed in-plane axial constraints.

6

Dynamics and controls of carbon use efficiency across China’s grasslands

51%

Hou G. , Sun J. , Wang J.

Polish Journal of Environmental Studies

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2018

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tom 27

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nr 4

EN

China’s grasslands play a significant role in the carbon cycle. Accurately evaluating carbon use efficiency (CUE) of grassland ecosystems is of great importance. Therefore, we adopted moderate resolution imaging spectroradiometer documents to explore dynamics and controls of CUE across grasslands of China from 2001 to 2010. Results demonstrated that CUE presented an increasing trend (0 to 0.0067 year⁻¹) in the most studies regions except for desert steppe (-0.0046 to 0 year⁻¹). At spatial scale, the precipitation, temperature, and aridity index significantly regulated the dynamics of CUE in alpine grasslands. Furthermore, the different mechanisms are explored at the transect scale, and CUE revealed the positive correlation with aridity index (R² = 0.92, P<0.0001) and precipitation (R² = 0.88, P<0.0001), but a negative correlation with temperature (R² = 0.92, P<0.0001) in alpine grasslands. However, in temperate grasslands, CUE exposed the negative correlation with aridity index (R² = 0.40, P<0.0001) and precipitation (R² = 0.54, P<0.0001), but a positive correlation with temperature (R² = 0.56, P<0.0001). Moreover, precipitation was decreasing with the increased temperature in the alpine grasslands (R² = 0.85, P<0.0001) and temperature of grasslands (R² = 0.19, P<0.0001). In conclusion, CUE had a slight increased trend across grasslands in China, with higher precipitation, aridity index, and lower temperature promoting CUE in the alpine region – nevertheless restraining the CUE variations in grassland temperature. The better heat and water conditions in temperate grasslands than in alpine grasslands resulted in higher CUE in temperate grasslands.

7

Buckling of cylindrical shells under external pressure in a Hamiltonian system

51%

Sun J. , Xu X. , Lim C. W.

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2014

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tom Vol. 52 nr 3

641--653

EN

In this article, the elastic buckling behavior of cylindrical shells under external pressure is studied by using a symplectic method. Based on Donnell’s shell theory, the governing equations which are expressed in stress function and radial displacement are re-arranged into the Hamiltonian canonical equations. The critical loads and buckling modes are reduced to solving for symplectic eigenvalues and eigenvectors. The buckling solutions are mainly grouped into four categories according to the natures of the buckling modes. The effects of geometrical parameters and boundary conditions on the buckling loads and modes are examined in detail.

8

Complexity of the Soundness Problem of Workflow Nets

51%

Liu G. J. , Sun J. , Liu Y. , Dong J. S.

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tom Vol. 131, nr 1

81--101

EN

Classical workflow nets (WF-nets for short) are an important subclass of Petri nets that are widely used to model and analyze workflow systems. Soundness is a crucial property of workflow systems and guarantees that these systems are deadlock-free and bounded. Aalst et al. proved that the soundness problem is decidable for WF-nets and can be polynomially solvable for free-choice WF-nets. This paper proves that the soundness problem is PSPACE-hard for WF-nets. Furthermore, it is proven that the soundness problem is PSPACE-complete for bounded WF-nets. Based on the above conclusion, it is derived that the soundness problem is also PSPACE-complete for bounded WF-nets with reset or inhibitor arcs (ReWF-nets and InWF-nets for short, resp.). ReWF- and InWF-nets are two extensions to WF-nets and their soundness problems were proven by Aalst et al. to be undecidable. Additionally, we prove that the soundness problem is co-NP-hard for asymmetric-choice WF-nets that are a larger class and can model more cases of interaction and resource allocation than free-choice ones.

9

An improved region-growth algorithm for dense matching

51%

Xing Y. J. , Meng J. J. , Sun J. , Wang Z. Q.

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tom Vol. 18, nr 1-2

323--326

EN

Purpose: Improve the accuracy and speed of the region-growth algorithm between two 2D images. Design/methodology/approach: The algorithm includes two parts: the selection of seeds points and propagation. Some improvements are made in each one. For the first part, the best-first strategy is used to assure the accuracy of seeds. The epipolar line constraint and continuity constraint reduce the double phase matching course into single phase matching. For the second one, a dynamic and adaptive window is adopted instead of the large window. Findings: In the first section, the process of searching and the computational duties are decreased in large extent. And in the second one, the adaptive window makes the searching course more efficient in time and space. It is really difficult to get the most suitable window to search for the points as soon as possible. If it can be easily got, it will advance the efficiency of search. It is the future work. Practical implications: The method can be used in many different images, such as the structural images and the facial images. Originality/value: The original value is the region-growth algorithm, and in this paper I made some betterments to advance the efficiency and accuracy.

10

All-optical frequency down-conversion based on cross-phase modulation in high nonlinearity dispersion-shifted fiber for WDM radio over fiber application

51%

Yang H. , Sun J. , Du Q.

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2009

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tom Vol. 39, nr 1

51--62

EN

Simultaneous all-optical frequency down-conversion technique based on cross-phase modulation in a high nonlinearity dispersion-shifted fiber is proposed and verified by simulation, and its application to a wavelength-division-multiplexing (WDM) radio over fiber (ROF) is proposed. Error-free simultaneous all-optical frequency down-conversion of the 16 WDM ROF upstream channels is achieved. The simulated results show the performance of WDM signals is in good accordance with a single signal without any interference, and the power difference of two beat frequencies of the down-conversion signal is independent of the optical local oscillator power. The wavelength span of larger than 20 nm for down-conversion signal can be obtained.

11

Toxicity evaluation of antibiotics in piggery wastewater by luminescent bacteria

51%

Sun J. , Li W. , Zheng P. , Zhu J.

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nr 3

EN

Antibiotics, as special pollutants in piggery wastewater, have negative effects on wastewater treatment processes. However, it is difficult to obtain a clear understanding of the toxic potency of antibiotics using the common inhibitory experiments of wastewater because of their low concentrations. Therefore, this study for the first time reports research on examining the toxic strength of piggery wastewater containing antibiotics by acute toxicity experiments using luminescent bacteria. Also reported herein for the first time were the mixed toxic effects of different antibiotics on luminescent bacteria using orthogonal experimental designs. Results showed that piggery wastewater had high ecotoxicity equal to 24.6 mg∙L⁻¹ HgCl₂, and the toxicity units (TU) of Chlortetracycline, amoxicillin, florfenicol, and sulfamethazine (SM₂) were 85.5, 64.72, 1.27, and 1.20, respectively, which fell under high or significant ecotoxicity according to the Toxicity Classification System (TCS). The IC₁₀ values indicated that the antibiotics could impose single or mixed toxic effects on luminescent bacteria even in trace concentrations. Among these antibiotics, Chlortetracycline was the most significant one needing more attention in the treatment of wastewater-containing antibiotics.

12

Conductometric titration studying on hollow microspheres preparation

51%

Cheng J. , Sun J. , Lin H. , Wei D.

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2006

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tom T. 51, nr 9

643-647

EN

Hollow microspheres were prepared via osmotic swelling. In order to study preparation process, a series of latex particles with different core/shell weight ratio were prepared by seeded emulsion polymerization. The content of surface carboxyl groups in the latex particles obtained from conductometric titration curve was used to determine the threshold core/shell weight ratio for hollow microspheres. Additionally, the rheology and opacity were studied. The results showed that the optimal core/shell weight ratio obtained from the conductometric titration curve was in agreement with the ratio acquired from transmission electron microscopy (TEM) analysis, the rheology and opacity studies.

PL

Puste mikrokulki były otrzymane za pomocą pęcznienia osmotycznego. Metodą polimeryzacji emulsyjnej z zastosowaniem różnych stosunków wagowych składników typu rdzeń/powłoka otrzymano dwie serie cząstek różniących się ilością użytego lateksu (tabele 1-3). W celu określenia granicznej wartości stosunku wagowego rdzeń/powłoka zapewniającego otrzymanie pustych mikrokulek zaproponowano nową metodę miareczkowania konduktometrycznego. Porównawczo zastosowano typową metodę elektronowej mikroskopii transmisyjnej (TEM) uzyskując podobne wyniki. Dodatkowo zbadano lepkość (tabela 5) i współczynnik nieprzezroczystości (tabela 6) uzyskanych próbek.

13

A novel multi-objective discrete particle swarm optimization with elitist perturbation for reconfiguration of ship power system

51%

Zhang L. , Sun J. , Guo C.

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nr Special Issue S3

EN

A novel multi-objective discrete particle swarm optimization with elitist perturbation strategy (EPSMODPSO) is proposed and applied to solve the reconfiguration problem of shipboard power system(SPS). The new algorithm uses the velocity to decide each particle to move one step toward positive or negative direction to update the position. An elitist perturbation strategy is proposed to improve the local search ability of the algorithm. Reconfiguration model of SPS is established with multiple objectives, and an inherent homogeneity index is adopted as the auxiliary estimating index. Test results of examples show that the proposed EPSMODPSO performs excellent in terms of diversity and convergence of the obtained Pareto optimal front. It is competent to solve network reconfiguration of shipboard power system and other multi-objective discrete optimization problems

14

A multi-objective fuzzy genetic algorithm for job-shop scheduling problems

51%

Xing Y. J. , Wang Z. Q. , Sun J. , Meng J. J.

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tom Vol. 17, nr 1-2

297--300

EN

Purpose: Many uncertain factors in job shop scheduling problems are critical for the scheduling procedures. There are not genetic algorithms to solve this problem drastically. A new genetic algorithm is proposed for fuzzy job shop scheduling problems. Design/methodology/approach: The imprecise processing times are modeled as triangular fuzzy numbers (TFNs) and the due dates are modeled as trapezium fuzzy numbers in this paper. A multi-objective genetic algorithm is proposed to solve fuzzy job shop scheduling problems, in which the objective functions are conflicting. Agreement index (AI) is used to show the satisfaction of client which is defined as value of the area of processing time membership function intersection divided by the area of the due date membership function. The multi-objective function is composed of maximize both the minimum agreement and maximize the average agreement index. Findings: Two benchmark problems were used to show the effectiveness of the proposed approach. Experimental results demonstrate that the multi-objective genetic algorithm does not get stuck at a local optimum easily, and it can solve job-shop scheduling problems with fuzzy processing time and fuzzy due date effectively. Research limitations/implications: In this paper only two objective functions of genetic algorithm are taken into consideration. Many other objective functions are not applied to this genetic algorithm. Originality/value: A new multi-objective fuzzy genetic algorithm is proposed for fuzzy genetic algorithm. The genetic operations can search the optimization circularly.

15

Removal of trivalent chromium from aqueous solutions by amphiphilic core-shell poly(methyl acrylate)/silk sericin nanospheres

51%

Song Y. , Jin Y. , Sun J. , Wei D.

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2007

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tom T. 52, nr 11-12

880-884

EN

Well-defined, core-shell poly(methyl acrylate/silk sericin) (PMA-SS) nanospheres, ranging from 100 to 150nm in diameter, were prepared via a direct graft copolymerisation of methyl acrylate (MA) with silk sericin (SS). The polymerisation was induced by a small amount of tert-butyl hydroperoxide (TBHP) in water at temp. 353K. The PMA-SS core-shell nanospheres were used as adsorbent in a series of batch adsorption experiments for the removal of trivalent chromium from aqueous solutions. The experimental results showed that PMA-SS nanospheres were an effective adsorbent for trivalent chromium from aqueous solution, and the maximum amount of adsorption reached 4.876mg Cr3+/g of sorbent within the experimental range. With the increase in pH values of solutions, the adsorption increased obviously, while the addition of electrolyte had a little effect on the adsorption. The adsorption equilibrium was reached after about 3h. The adsorption of trivalent chromium by PMA-SS nanospheres was significantly higher than that done by SS powder under the same adsorption conditions.

PL

Metodą bezpośredniej kopolimeryzacji szczepionej akrylanu metylu (MA) na serycynie (SS) otrzymano nanosfery typu rdzeń-otoczka (PMA-SS) o średnicach zawierających się w przedziale 100-150nm (rys. 1 i 2). Kopolimeryzację prowadzono w temp. 353K w roztworze wodnym i inicjowano za pomocą wodoronadtlenku tert-butylu (TBHP). Zbadano zdolność otrzymanych nanosfer PMA-SS do adsorbowania Cr3+ z roztworów wodnych. Stwierdzono, że ilość zaadsorbowanego Cr3+ rośnie wraz ze wzrostem stężenia początkowego roztworu (Co) osiągając wartość 4,876mg Cr3+/g sorbentu w temp. 293K w przypadku roztworu o pH=6,0 i Co=3,5mg Cr3+/L (rys. 3). Zaobserwowano, że w badanym przedziale pH od 4,0 do 6,0 adsorpcja wyraźnie rośnie ze wzrostem pH (rys. 4). Badania wykazały także, że ilość zaadsorbowanego Cr3+ nieznacznie wzrasta pod wpływem dodania do roztworu niewielkiej ilości KCl jako dodatkowego elektrolitu (rys. 5). Na podstawie badań kinetyki adsorpcji określono, że równowaga jest osiągana po ok. 3 godz. Na zakończenie porównano wyniki adsorpcji Cr3+ za pomocą nanosfer PMA-SS z wynikami uzyskanymi w takich samych warunkach z zastosowaniem jako adsorbenta samego proszku SS i stwierdzono zdecydowanie większą efektywność adsorpcji w pierwszym przypadku.

16

The impact of climate change and human activity on net primary production in Tibet

51%

Qin X. , Sun J. , Liu M. , Lu X.

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2016

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tom 25

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nr 5

EN

The Tibetan Plateau has faced environmental degradation in recent years due to intensified human activity and climate change. In this study, the dynamics of net primary production (NPP), annual mean temperature (AMT), annual mean precipitation (AMP), number of animals (NA), number of rural laborers (NRL), and animal husbandry (AH) were analyzed and the response of NPP to climate and human activity explored. The results show that NPP was increasing gradually from northwest to southeast and is similar to the distribution of AMP. In addition, NA, NRL, and AH cluster around Lhasa. Moreover, AMP had a negative correlation with NPP in Tibet while AMT has a positive effect on NPP. Moreover, because of the large number of livestock there is a negative relationship between NA and NPP in most Tibetan regions. Furthermore, it was found that human activity made a higher contribution to NPP in Tibet (24.73%) than climate factors (17.28%). It is, therefore, necessary to further explore the relationship between human activity and the vegetation dynamic in the region.

17

Effect of lactic acid fermented soyabean meal on the growth performance, intestinal microflora and morphology of weaned piglets

45%

Wang N. F. , Chen Q. , Le G. W. , Shi Y. H. , Sun J.

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nr 1

75-85

18

Development and application of the integration of physical activity into health care - a scoping review

45%

Sun J. , Ren Y. , Qian G. , Yue S. , Szumilewicz A.

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2024

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tom 31

|

nr 2

19

A novel alkaline protease with antiproliferative activity from fresh fruiting bodies of the toxic wild mushroom Amanita farinosa

45%

Sun J. , Zhao Y. , Chai H. , Wang H. , Ng T. B.

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nr 4

EN

A novel protease with a molecular mass of 15 kDa was purified from fresh fruiting bodies of the wild mushroom Amanita farinosa. The purification protocol entailed anion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, cation exchange chromatography on SP-Sepharose, and gel filtration by fast protein liquid chromatography on Superdex 75. The protease was unadsorbed on DEAE-cellulose but adsorbed on Affi-gel blue gel and SP-Sepharose. It demonstrated a single 15-kDa band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS/PAGE) and a 15-kDa peak in gel filtration. The optimal pH and optimal temperature of the protease were pH 8.0 and 65 °C, respectively. Proliferation of human hepatoma HepG2 cells was inhibited by the protease with an IC50 of 25 µM. The protease did not have antifungal or ribonuclease activity.

20

Determination of the trace lead in seasoning samples with derivative hydride generation atomic absorption spectrometry

45%

Liang S. , Ha J. , Sun H. , Kang W. , Sun J.

Chemia Analityczna

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2003

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tom Vol. 48, No. 4

723-732

EN

A new method for the determination of lead traces in seasoning by derivative hydride generation atomic absorption spectrometry (D-HGAAS) has been developed. The conditions influencing the derivative absorbance of lead were evaluated and optimised. The detection limit and sensitivity of the proposed method were improved 8.8 times and 26 times, respectively in comparison to those of the conventional hydride generation atomic absorption spectrometry. The characteristic concentration of lead (referring to derivative absorbance of 0.0044) was 0.017 ug L(-1) at maximum sensitivity. The detection limit (3sigma) for lead in the real sample equalled 0.96 ng g(-1) for 5.0 g sample at maximum sensitivity. The method was applied to the determination of lead in seasoning samples with a recovery range of 92-103%.

PL

Opracowano nową metodę oznaczania śladowych ilości ołowiu w przyprawach za pomocą pochodnej absorpcyjnej spektrometrii atomowej z generacją wodorków. Oszacowano i zoptymalizowano warunki wpływające na pochodną absorbancji ołowiu. Granica detekcji i czułość metody były lepsze odpowiednio 8.8 i 22 razy w porównaniu z konwencjonalną atomową spektrometrią absorpcyjną z generacją wodorków. Charakterystyczne stężenie (dla pochodnej absorbancji 0.0044) wynosiło 0.017 ng L(-1) przy maksymalnej czułości układu. Granca detekcji (3 Sigma) dla ołowiu w próbce rzeczywistej wynosiła 0.96 ng g(-1) (przy maksymalnej czułości układu i masie próbki 5.0 g). Metodę zastosowano do oznaczania ołowiu w przyprawach. Strwierdzono, że odzysk ołowiu waha się. w granicach 92-103%.