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1

Ag+/S2O8 2– system for the degradation of aqueous flutriafol

Yang H., Zhou W., Yang L., Deng J., Hu Q., Wei H., Au C., Yi B.

Environment Protection Engineering

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2018

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Vol. 44, nr 2

57--72

EN

The degradation of flutriafol in aqueous persulfate (S2O82–) system in the presence of selected transition metal ions was investigated. In the presence of Ag+ or Fe2+, flutriafol degradation occurs, whereas in the presence of Mn2+, Co2+, Ni2+, Cu2+, Zn2+ and Bi3+ ions, the degradation is less than 15%. The Ag+/ S2O82– aqueous system being the most effective was adopted for experimental and theoretical investigations. It was confirmed that pH of 3.0 is the most suitable, and that both · SO4–and ·OH– radicals are the main active species to afford flutriafol degradation, with the former contributes more than the latter. To elucidate degradation mechanism, molecular orbital calculations were performed and reaction intermediates identified by GC/MS and HPLC/MS/MS analyses. Three degradation pathways are proposed that involve the cleavage of C–N and C–C bonds as a result of ·SO4– attack, as well as the formation of hydroxylated products due to · OH radicals.

2

Development of WC-Inconel composites using selective laser melting

Nguyen Q. B., Zhu Z., Chua B. W., Zhou W., Wei J., Nai S. M. L.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 4

1410--1420

EN

In the present study, selective laser melting (SLM) was used to successfully fabricate Inconel 718–tungsten carbide (WC) composites. The processing parameter optimization results reveal that nearly non-porous composites (99.54%) were achieved with the laser power of 220 W, scanning speed of 850 mm s−1, and the hatch spacing of 150 μm. The microstructural characterization unveils that elongated grain structure in the heat flow direction was observed in the case of pure IN718 while WC particles served as obstacles to hinder the grain growth in the composites. The formation of in situ intermediate layer and the strong interfacial bonding between WC super-hard particles and the matrix acted as load bearing and significantly contribute to the overall properties of composites. Mechanical tests indicate significant improvements of microhardness and tensile strengths, although a drop in strength was observed when the amount of WC reached 15 wt.%. In addition, the thermal experiment shows that the composites are dimensionally stable at higher temperature compared to their monolithic counterpart. The findings suggest that the developed IN718-WC composites can be utilized in many critical engineering applications in nuclear sector.

3

Yellowfin tuna (Thunnusalbacares) fishing ground forecasting model based on bayes classifier in the South China Sea

Zhou W., Li A., Ji S., Qiu Y.

Polish Maritime Research

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2017

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S 2

140--146

EN

Using the yellowfin tuna (Thunnusalbacares,YFT)longline fishing catch data in the open South China Sea (SCS) provided by WCPFC, the optimum interpolation sea surface temperature (OISST) from CPC/NOAA and multi-satellites altimetric monthly averaged product sea surface height (SSH) released by CNES, eight alternative options based on Bayes classifier were made in this paper according to different strategies on the choice of environment factors and the levels of fishing zones to classify the YFT fishing ground in the open SCS. The classification results were compared with the actual ones for validation and analyzed to know how different plans impact on classification results and precision. The results of validation showed that the precision of the eight options were 71.4%, 75%, 70.8%, 74.4%, 66.7%, 68.5%, 57.7% and 63.7% in sequence, the first to sixth among them above 65% would meet the practical application needs basically. The alternatives which use SST and SSH simultaneously as the environmental factors have higher precision than which only use single SST environmental factor, and the consideration of adding SSH can improve the model precision to a certain extent. The options which use CPUE’s mean ± standard deviation as threshold have higher precision than which use CPUE’s 33.3%-quantile and 66.7%-quantile as the threshold

4

Electrostatic Hazards Assessment of Nitramine Explosives: Resistivity, Charge Accumulation and Discharge Sensitivity

Peng Q., Cao W., Zhou W., He Z., Jiang W., Chen W.

Central European Journal of Energetic Materials

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2016

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Vol. 13, no. 3

755--769

EN

The electrostatic hazards of nitramine explosives (RDX, HMX) were assessed in this paper. The resistivities of different particle-size RDX and HMX were tested by a device designed and manufactured according to the standard ISO/IEC 80079-20-2:2016. This work shows that the resistivities of uncompacted RDX and HMX increase as the particle size decreases. Charging characteristics test experiments were also carried out using a so-called sieve method. Using this method, the influence of aperture size on charge accumulation of RDX was studied, and the characteristics of electrostatic accumulation of different particle-size RDX and HMX sieved with 50 mesh standard sieve were compared. The results show that the absolute value of the charge accumulation increases as the mesh number increases (i.e. the aperture size decreases), and increases as the particle size is decreased, indicating that nano-sized RDX and nano-sized HMX accumulate static electricity more easily than conventional micron-sized ones. Finally, the electrostatic discharge (ESD) sensitivity of nano-sized RDX and nano-sized HMX was investigated. Nano-sized nitramine explosives were found to have a higher ESD sensitivity than micron-sized ones.

5

Epileptic seizure detection based on improved wavelet neural networks in long-term intracranial EEG

Geng D., Zhou W., Zhang Y., Geng S.

Biocybernetics and Biomedical Engineering

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2016

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Vol. 36, no. 2

375--384

EN

Automatic seizure detection is of great importance for speeding up the inspection process and relieving the workload of medical staff in the analysis of EEG recordings. In this study, a method based on an improved wavelet neural network (WNN) is proposed for automatic seizure detection in long-term intracranial EEG. WNN combines the traditional back propagation neural network (BPNN) with wavelet transform. Compared with classic WNN architectures, a modified point symmetry-based fuzzy c-means (MSFCM) algorithm is applied to the initialization of wavelet transform's translations, which has been successful in multiclass cancer classification. In addition, Fast-decaying Morlet wavelet is chosen as the activation function to make the WNN learn faster. Relative amplitude and relative fluctuation index are extracted as a feature vector to describe the variation of EEG signals, and the feature vector is then fed into WNN for classification. At last, post-processing including smoothing, channel fusion and collar technique is adopted to achieve more accurate and stable results. This system performs efficiently with the average sensitivity of 96.72%, specificity of 98.91% and false-detection rate of 0.27 h_1. The proposed approach achieves high sensitivity and low false detection rate, which demonstrates its potential for clinical usage.

6

Comparison of the Variation of Soil Respiration in Carbon Cycle in Temperate and Subtropical Forests and the Relationship with Climatic Variables

Shi Z., Zhang Y., Chen B., Zhou W., Du E., Fang J.

Polish Journal of Ecology

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2015

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Vol. 63, nr 3

365--376

EN

Forest soil respiration (SR) has become a vital issue in global change ecology because of its critical role in global warming processes. However, SR remains the least understood component of the terrestrial carbon cycle because of its high spatial-temporal variability, inaccessibility of the soil substrate, and the high cost of measurement equipment. This study investigated the spatial and temporal variations of SR in six temperate and subtropical forest sites in eastern China. Seasonal variations of SR, the relationship between SR and soil temperature (ST) and volumetric water content (SW) were analyzed. Mean monthly SR varied seasonally and peaked in summer. SR varied temporally with ST (R2 = 0.43∼0.79) in different sites and varied spatially with latitude (R2 = 0.68). The responses of SR to the changes of SW varied across different sites and forest types. Their relationships were simulated by piecewise functions in the north three sites. The modules of ST and SW showed that ST is the dominant environmental factor in regulating seasonal dynamics of SR. This study is the first to examine the temporal and spatial variations of SR using a consistent method in situ in temperate and subtropical forests in eastern China. The results provide a scientific basis for accurately assessing future soil CO2 efflux as a result of climate changes, and aid predictions of the changes of forest SR.

7

Research on the influence of excavation and loading on Z-Direction displacement in surrounding soil mass

Li X., Zhou W., Han L., Xi W. J., Crusoe Jr. G. E.

Archives of Mining Sciences

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2014

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Vol. 59, no. 4

959--970

EN

To probe into the pattern in which the excavation and loading process have on such factors as stress and displacement in neighboring regions of deep open pits, a mechanical unloading model in coal mining process and another model for the loading process are set up respectively. Besides, FLAC3D software is used to simulate dynamic excavating and loading process in open pits and record such data as the unbalanced stress, unloading strength and displacement fluctuations, which further serve as basis for studying the functional relationship about different mining heights and scope of influence using fitting method. The research results indicate that the unloading strength enhances with increasing mining depth in a linear fashion. In addition, a noticeable displacement circle takes shape around the stope, which would also extends with growing mining depth. As to waste loading, it brings about large-scale surface subsidence in neighboring regions, which follows a logarithm function convergence pattern with the distance away from the dump border. Under combined effects of excavation and loading, the value of the soil mass displacement would increase with growing mining depth and loading height. Specifically, the soil displacement at a distance of 100 m away from the stope border (around 200 m away from the outer dump border) is abnormally significant and it further develops at a rate of 0.0228 mm/h.

PL

W celu zbadania zależności pomiędzy procesami wydobycia i składowania urobku a takimi czynnikami jak naprężenia i przemieszczenia w sąsiadujących partiach głębokich wyrobisk odkrywkowych, wykorzystano model mechaniczny procesu urabiania węgla oraz model procesu jego składowania. Wykorzystano oprogramowanie FLAC 3D do symulacji procesów wydobycia i składowania w wyrobiskach odkrywkowych, zapisano odpowiednie dane: niezrównoważone naprężenia, wytrzymałość w trakcie odciążania oraz wahania przemieszczeń gruntu, które wykorzystane zostały następnie jako podstawa do badania funkcjonalnych zależności pomiędzy wysokością poziomu wydobycia a skalą oddziaływania, przy użyciu odpowiednich metod dopasowania. Wyniki badań wskazują, że wytrzymałość w trakcie odciążania wzrasta liniowo z głębokością. Ponadto, zarejestrowano wyraźny kołowy przebieg przemieszczenia wokół zbocza, który także rośnie z głębokością. W przypadku obciążenia wskutek urobku odpadowego, zanotowano obniżenia terenu o dużym zasięgu o przebiegu konwergencji opisanym funkcją logarytmiczną odległości od miejsca składowania urobku odpadowego. W przypadku wystąpienia połączonych efektów wydobycia i składowania, wielkość przemieszczeń mas gruntu wzrastać będzie wraz z głębokością prowadzenia prac i wysokością składowania. Przemieszczenie gruntu w odległości 100 m od brzegu wyrobiska (ok. 200 od zewnętrznej granicy składowiska) okazuje się niepokojąco duże i postępujące w tempie 0.0228 mm/h).

8

Separating Storm surge from Tidal Level Based on Wavelet Packet Transform

He S., Zhou W.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 3b

107--109

EN

A method of wavelet packet transformation (WPT) is presented in this paper, which regards the tidal level as a signal with containing different frequency of astronomical tidal components and storm surge components. The tidal level signal can be decomposed serials of frequency bands signals by using WPT to carry out time-frequency analysis for procuring the representative frequency bands of storm surge. Then the storm surge process gained by reconstructing the exclusive decomposed wavelet packet coefficients. Taken the typhoon NO.9608 measured tidal level of Xiamen tide station as an example, the storm surge calculates by using the presented method, which compared the value calculated by transformation linear method with the measured value. The result shows that the suggested method can preferably separate storm surge and provide a new way to separate storm surge from short-term tidal level material.

PL

W artykule przedstawiono algorytm realizacji transformaty Falkowej, analizujący dane o astronomicznych parametrach pływów oraz podniesieniu się poziomu morza w czasie sztormu (nagon). Opracowana metoda pomaga w efektywnym odróżnieniu tych dwóch zjawisk, co ogranicza ryzyko fałszywego alarmu. Na podstawie rzeczywistych danych, dokonano jej porównania z metodami liniowymi, co wykazało sprawniejsze działanie.

9

RSM-optimized IRAE sample pretreatment and HPLC simultaneous determination of Tryptanthrin, indigo, and indirubin from Chinese herbal medicine Radix Isatidis

Zhou W., Zhang X. Y., Lv Y. P., Liu X. D., Xu C., Duan G. L.

Acta Chromatographica

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2013

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Vol. 25, no. 2

297--315

EN

Radix Isatidis has widely useful activities including anti-virus, anti-bacterial. Tryptanthrin, indigo, and indirubin are active ingredients in R. Isatidis. Response surface methodology (RSM)-optimized infrared-assisted extraction (IRAE) was developed and combined with HPLC for simultaneous determination of tryptanthrin, indigo, and indirubin from R. Isatidis. IRAE were investigated through extraction yields of the three components and optimized by RSM. The optimum conditions were as follows: infrared power of 129 W, solid/liquid ratio of 1:40 g/mL, and irradiation time of 22.5 min. IRAE conditions obtained by RSM were not only accurate, but also had practical value reflecting the expected optimization. Subsequently, this novel IRAE method was evaluated by extraction yield of the components of R. Isatidis samples from different regions. Compared with common extraction methods including maceration extraction (ME), reflux extraction (RE), ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE), IRAE showed higher yield with advantages of no limitation of solvent selection, low cost, convenience under optimum extraction conditions. These results suggested the potential of RSM-optimized IRAE for extraction and analysis of the water-/fat-soluble compositions of Chinese herbal medicine. A simple chromatographic separation for simultaneous determination of tryptanthrin, indigo, and indirubin from Chinese herbal medicine R. Isatidis was performed on a C18 column (Diamonsil 150 mm × 4.6 mm i.d., 5 μm) with a mobile phase isocratic consisting of methanol and water at a flow-rate of 0.8 mL min -1. The retention times of tryptanthrin, indigo, and indirubin were 15.4, 31.9, and 58.6 min, respectively. The linear equations were obtained as follows: y = −3094.5744 + 21208.792x for tryptanthrin (R = 0.9998, 0.9–18.0 μg mL -1), y = 4730.0448 + 30180.567x for indigo (R = 0.9997, 0.5–10.0 μg mL−1) and y = −6582.9045 + 67069.312x for indirubin (R = 0.9997, 0.4–8.0 μg mL -1). The result showed that RSM-optimized IRAE was a simple, efficient pretreatment method for the analysis of complex matrix.

10

Large-area self assembled monolayers of silica microspheres formed by dip coating

Wang Y., Chen L., Yang H., Guo Q., Zhou W., Tao M.

Materials Science Poland

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2010

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Vol. 28, No. 2

467--478

EN

Formation by dip coating of highly ordered and closely packed, self assembled monolayers (SAMs) of microsized silica spheres has been reported. Under optimized coating conditions, SAMs were formed with 2 žm diameter silica spheres on record-breakingly large areas, measuring 3×10 mm2 on silicon substrates and 1.5×11 mm2 on glass substrates. The SAMs structure and their spatial extension were significantly influenced by the concentration of the solution, withdrawal speed, immersion time, relative humidity, types of solvent and substrate material. The SAMs of silica microspheres provide a glimpse into the wide range of photonic applications for dip coating such as surface texturing and anti-reflection coatings.

11

Effect of Yarn Properties on the Pilling of Cashmere Knitted Fabric

Li L., Jia G., Zhou W.

Fibres & Textiles in Eastern Europe

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2009

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Vol. 17, no. 6 (77)

76--79

EN

The factors influencing fabric pilling include the fibre properties, yarn properties, fabric structure and wear condition. As an expensive textile material, cashmere fibre exhibits a small diameter, short length and smooth surface. The pilling of cashmere knitted fabric has attracted the attention of consumers, manufacturers and researchers. In this work, the effect of yarn properties on the pilling rates of cashmere knitted fabric is investigated. The results showed that the dye colour of cashmere fibers is of primary importance for the pilling rates of cashmere knitted fabric. The relationship between the pilling rates and yarn properties was obtained by using optimal scaling regression analysis. The pilling rates of different coloured fabrics were compared.

PL

Czynnikami wpływającymi na jakość tkanin i dzianin są właściwości włókien i przędzy, struktura materiału, i warunki użytkowania. Włókna kaszmirowe będące kosztownym surowcem charakteryzują się małą średnicą, gładkością powierzchni oraz małą długością włókien odcinkowych. Piling dzianin kaszmirowych skupia uwagę wytwórców, konsumentów i naukowców. W artykule przedstawiono badania wpływu właściwości włókien na piling dzianin. Wyniki wykazały, ze kolor włókien posiada bardzo duże znaczenie dla pilingu dzianin. Zależności pomiędzy kolorem włókien a pilingiem zostały określone przez oznaczenie współczynników regresji. Porównano wielkość pilingu przy rożnych kolorach włókna.