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1

An improved feature extraction method for rolling bearing fault diagnosis based on MEMD and PE

Zhang H., Zhao L., Liu Q., Luo J., Wei Q., Zhou Z., Qu Y.

Polish Maritime Research

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2018

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S 2

98--106

EN

The health condition of rolling bearing can directly influence to the efficiency and lifecycle of rotating machinery, thus monitoring and diagnosing the faults of rolling bearing is of great importance. Unfortunately, vibration signals of rolling bearing are usually overwhelmed by external noise, so the fault frequencies of rolling bearing cannot be readily obtained. In this paper, an improved feature extraction method called IMFs_PE, which combines the multivariate empirical mode decomposition with the permutation entropy, is proposed to extract fault frequencies from the noisy bearing vibration signals. First, the raw bearing vibration signals are filtered by an optimal band-pass filter determined by SK to remove the irrelative noise which is not in the same frequency band of fault frequencies. Then the filtered signals are processed by the IMFs_PE to get rid of the relative noise which is in the same frequency band of fault frequencies. Finally, a frequency domain condition indicator FFR(Fault Frequency Ratio), which measures the magnitude of fault frequencies in frequency domain, is calculated to compare the effectiveness of the feature extraction methods. The feature extraction method proposed in this paper has advantages of removing both irrelative noise and relative noise over other feature extraction methods. The effectiveness of the proposed method is validated by simulated and experimental bearing signals. And the results are shown that the proposed method outperforms other state of the art algorithms with regards to fault feature extraction of rolling bearing.

2

PIV measurement of tube-side in a shell and tube heat exchanger

Wang K., Zhang Z., Liu Q., Tu X., Hyoung-Bum K.

Polish Journal of Chemical Technology

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2018

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Vol. 20, nr 1

60--66

EN

In order to improve the performance of the shell and tube heat exchanger, a porous baffle and a splitter bar are employed in this research. Through the arrangement of the porous baffle in the tube-side inlet and the splitter bar in the tube, the flow distribution of liquid in the heat exchanger is improved. PIV technology is used to investigate the unsteady flow in the tube-side inlet and the outlet of different models. The porous baffle significantly improves the flow of fluid in the shell and tube heat exchanger, especially by eliminating/minimizing the maldistribution of fluid flow in the tube-side inlet. The performance of the arc baffle is better than that of the straight baffle. The splitter bar has a minimal effect on the flow field of the tube-side inlet, but it effectively improves the flow in the tube bundle and restrains the vortex generation in the tube-side outlet.

3

Optimization and evaluation of alkali-pretreated Paeonia ostii seed coats as adsorbent for the removal of MB from aqueous solution

Liu Q., Li T., Zhang S., Qu L., Ren B.

Polish Journal of Chemical Technology

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2018

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Vol. 20, nr 3

29--36

EN

A novel efficient adsorbent, alkali-pretreated Paeonia ostii seed coats (AP-PSC), was investigated for the removal of methylene blue (MB) dye from solution. Orthogonal array design was applied to optimize the process parameters viz. alkali concentration, liquid-solid ratio (LSR) and pretreatment time. The results revealed that the optimal pretreatment conditions were at 0.8% (w/w) NaOH with LSR of 0.35 L g–1 treating for 50 min. Equilibrium and kinetic studies indicated that Langmuir isotherm and Pseudo-second-order models described the experimental data well. The maximum adsorption capability was of 368.2 mg g–1 for MB at 25°C. Thermodynamic parameters suggested that the AP-PSC adsorption process was physical, endothermic and spontaneous. Furthermore, the adsorption process was influenced by several interactive mechanisms, including ion-exchange, as well as Van der Waals forces and hydrogen bonds that occur concomitantly. It was concluded that AP-PSC may be potential as an efficient adsorbent to remove MB from solution.

4

Oil-assisted flotation of fine hematite using sodium oleate or hydroxamic acids as a collector

Li H., Liu M., Liu Q.

Physicochemical Problems of Mineral Processing

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2018

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Vol. 54, iss. 4

1130--1145

EN

Micro-flotation and batch flotation tests were carried out on fine (-20 µm) hematite to investigate the influences of non-polar oil when sodium oleate, octyl hydroxamic acid, or oleoyl hydroxamic acid was used as a collector. Both micro-flotation and batch flotation tests were performed using single hematite mineral and/or artificial mixed minerals (hematite:quartz = 1:1), and kerosene was utilized as the neutral oil. The experimental results showed that the addition of a kerosene emulsion benefited hematite recovery in the micro-flotation tests where a froth layer did not exist. In the batch flotation where a froth layer existed, kerosene behaved differently when used in conjunction with the three collectors. Kerosene helped improve the batch flotation when sodium oleate or oleoyl hydroxamic acid was used as a collector. However, it reduced concentrate weight yield, grade and recovery to a noticeable extent when octyl hydroxamic acid was used as a collector, especially at low dosages. In addition, single hematite batch flotation kinetics tests coupled with water recovery measurement were carried out to study the role of kerosene at different collector dosages. It was observed that water drainage and the resulting froth destabilization by kerosene was dominant at low collector dosages, especially in the flotation using octyl hydroxamic acid. At higher collector dosages, the water drainage and froth destabilization effect by kerosene was possibly counter-balanced by the higher hematite surface hydrophobicity and bubble surface tension gradient, which led to more stable froth layer.

5

A continuous-time distributed algorithm for solving a class of decomposable nonconvex quadratic programming

Zhao Y., Liu Q.

Journal of Artificial Intelligence and Soft Computing Research

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2018

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Vol. 8, No. 4

283--291

EN

In this paper, a continuous-time distributed algorithm is presented to solve a class of decomposable quadratic programming problems. In the quadratic programming, even if the objective function is nonconvex, the algorithm can still perform well under an extra condition combining with the objective, constraint and coupling matrices. Inspired by recent advances in distributed optimization, the proposed continuous-time algorithm described by multi-agent network with consensus is designed and analyzed. In the network, each agent only accesses the local information of its own and from its neighbors, then all the agents in a connected network cooperatively find the optimal solution with consensus.

6

Synthesis, Characterization and Thermal Decomposition of a New Energetic Salt of 1H,1′H-5,5′-Bistetrazole-1,1′-diol

Xiao L., Jin B., Shang Y., Liu Q., Guo Z., Peng R.

Central European Journal of Energetic Materials

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2018

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Vol. 15, no. 3

405--419

EN

1,1-Dimethylbiguanidium 1H,1′H-5,5′-bistetrazole-1,1′-diolate (MGBTO), a novel nitrogen-rich energetic salt, was synthesized by cation exchange. Its structure was characterized by elemental analysis, FTIR, NMR, DTA and TG-DTG. Single crystal X-ray diffraction analysis revealed that MGBTO was crystallized in the monoclinic space group C2/c. Thermal analysis demonstrated that its thermal stability extended up to 531.1 K. The nonisothermal kinetic and apparent thermodynamic parameters of the exothermic decomposition of MGBTO were determined by the Kissinger and Ozawa methods. Its detonation velocity and detonation pressure were calculated on the basis of the Kamlet-Jacobs equation and were 6342 m·s–1 and 15.78 GPa, respectively. The impact and friction sensitivities of MGBTO were quantified using standard BAM (10 kg drop hammer) procedures. The results revealed that the salt has good mechanical sensitivity (FS > 120 N, IS > 40 J), thus indicating its potential applications as an energetic material.

7

Research on the neuro-protective compounds in Terminalia chebula retz extracts in-vivo by UPLC–QTOF-MS

Zhang Y., Liu X., Gao S., Qian K., Liu Q., Yin X.

Acta Chromatographica

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2018

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Vol. 30, no. 3

169--174

EN

We have developed a strategy to analyze the components absorbed in the plasma and brain tissue of rats after intragastric administration of Terminalia chebula Retz extracts by ultra-performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UPLC–QTOF-MS). Nine components (gallic acid, methyl gallate, ferulic acid, ethyl gallate, brevifolin carboxylic acid, ellagic acid, galloflavin, arjugenin, and arjunic acid) and four metabolites were identified in plasma, and five components (ethyl gallate, brevifolin carboxylic acid, ellagic acid, arjugenin, and arjunic acid) were identified in the rat brain based on their fragmentation behaviors. The components present in the plasma were associated with the antioxidant activity of T. chebula Retz, and the components absorbed in the brain were associated with its neuro-protective effects. This approach allowed us to rapidly determine the active components of T. chebula Retz and develop a method for its quality control. This analysis method showed good resolution and high sensitivity, and is a potentially powerful tool for the determination of effective components of natural products.

8

Preparative separation of two alkaloids from devil pepper radix (Rauvolfia verticillata [Lour.] Baill.) by ph-zone-refining counter-current chromatography

Duan W. J., Liu Q., Zhao R. X., Mu Y., Guo L. P., Li D. P., Wang X.

Acta Chromatographica

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2018

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Vol. 30, no. 2

81--84

EN

A method was developed for the preparative separation of two alkaloids from the crude extract of the radix of Rauvolfia verticillata (Lour.) Baill. in a single run. The two-phase solvent system composed of petroleum ether–ethyl acetate–methanol–water (5:5:2:8, v/v), where triethylamine (40 mmol/L) was added to the upper organic phase as the stationary phase and hydrochloric acid (10 mmol/L) was added to the lower aqueous phase as the mobile phase, was selected for this separation by pH-zone-refining counter-current chromatography (PZRCCC). For the preparative separation, the apparatus was rotated at a speed 850 rpm, while the mobile phase was pumped into the column at 2 mL/min. As a result, 112 mg of reserpine and 21 mg of yohimbine were obtained from 3 g of crude extract in a single run. The analysis of the isolated compounds was determined by high-performance liquid chromatography (HPLC) at 230 nm with purities of over 91.0%, and the chemical identification was carried out by the data of electrospray ionization–mass spectrometry (ESI–MS) and nuclear magnetic resonance (NMR) spectroscopy. The technique introduced in this paper is an efficient method for preparative separation of reserpine and yohimbine from devil pepper radix. It will be beneficial to utilize medicinal materials and also useful for the separation, purification, and pharmacological study of Chinese herbal ingredients.

9

Preparation and characterization of (Co0:3Zn0:7)(Ti1–xSnx)Nb2O8 microwave dielectric ceramics

Tang B., Zhang X., Fang Z., Liu Q., Zhang S.

Materials Science Poland

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2017

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Vol. 35, No. 2

405--411

EN

Zn0.7Co0.3 (Ti1-xSnx)Nb2O8 (x = 0.1, 0.15, 0.2, 0.25, 0.3, 0.35) microwave ceramics were prepared by traditional solidstate reaction method. The influences of Sn substituted for Ti on the phase constitution, crystal structure and microwave dielectric properties of Zn0.7Co0.3 (Ti1-xSnx)Nb2O8 ceramics were discussed. The XRD patterns revealed the main phase of ZnTiNb2O8 and little content of Zn0.17Ti0.5Nb0.33O2 secondary phase. With further substitution of Sn, the lattice constant, volume and apparent density of the ceramics increased, the ceramic structure reached a maximal compactness at x = 0.2 which was shown on SEM. Tremendous improvement of Q × f and a declining trend of Ɛr and τf were obtained with increasing x value. Appropriate substitution value (x = 0.10) would ensure excellent microwave dielectric properties (Ɛr = 34.1, Q × f = 40562 GHz, τf =-5 ppm/°C) of the ceramics sintered at 1080 °C.

10

Intelligent Retail Forecasting System for New Clothing Products Considering Stock-out

Huang H., Liu Q.

Fibres & Textiles in Eastern Europe

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2017

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Vol. 25, no. 1 (121)

10--16

EN

Improving the accuracy of forecasting is crucial but complex in the clothing industry, especially for new products, with the lack of historical data and a wide range of factors affecting demand. Previous studies more concentrate on sales forecasting rather than demand forecasting, and the variables affecting demand remained to be optimized. In this study, a two-stage intelligent retail forecasting system is designed for new clothing products. In the first stage, demand is estimated with original sales data considering stock-out. The adaptive neuro fuzzy inference system (ANFIS) is introduced into the second stage to forecast demand. Meanwhile a data selection process is presented due to the limited data of new products. The empirical data are from a Canadian fast-fashion company. The results reveal the relationship between demand and sales, demonstrate the necessity of integrating the demand estimation process into a forecasting system, and show that the ANFIS-based forecasting system outperforms the traditional ANN technique.

PL

Poprawa dokładności prognozowania jest bardzo istotna, ale skomplikowana w przypadku przemysłu odzieżowego, zwłaszcza dla nowych produktów oraz szerokiego zakresu czynników wpływających na popyt. Wcześniejsze badania bardziej koncentrowały się na prognozowaniu sprzedaży, niż prognozowaniu popytu. Zmienne wpływające na popyt powinny zostać zoptymalizowane. W tym badaniu opracowano dwustopniowy inteligentny system prognozowania sprzedaży detalicznej przeznaczony dla nowych produktów odzieżowych. W pierwszym etapie, popyt jest określony za pośrednictwem oryginalnych danych dotyczących sprzedaży. Adaptacyjny neuronowy system danych rozproszonych (ANFIS) jest wprowadzony w drugim etapie do prognozowania popytu. Jednocześnie prezentowany jest proces selekcji danych. Dane empiryczne pochodzą z kanadyjskiej firmy.

11

Multivariate information dynamic monitoring system application of tunnel construction process model test

Liu Q., Chen J., Wei L., Huang P., Luo Y., Pu X.

Archives of Civil Engineering

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2016

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Vol. 62, nr 3

117--136

EN

Geomechnical model testing has been widely applied as a kind of research technique in underground engineering problems. However, during the practical application process, due to the influence of many factors, the desired results cannot be obtained. In order to solve this problem, based on the measurement requirements of the model test, combined with FBG(Fiber Bragg Grating) sensor technology and traditional measurement methods, an FBG monitoring system, Micro-multi-point displacement test system, resistance strain test system and surrounding rock pressure monitoring system are developed. Applying the systems to a model test of the tunnel construction process, the displacement in advance laws of tunnel face, radial displacement distribution laws and surrounding rock pressure laws are obtained. Test results show that a multivariate information monitoring system has the advantage of high precision, stability and strong anti-jamming capability. It lays a solid foundation for the real-time data monitoring of the tunnel construction process model test.

PL

Niniejsza praca omawia system dynamicznego monitorowania wieloczynnikowej informacji podczas badania modelu procesu budowy tunelu. Geometryczna metoda badania modelu jest skuteczną metodą badania poważnych problemów geotechnicznych, które wiążą się ze stosowaniem podobnych materiałów w pomieszczeniu, tworzeniem podobnych modeli na podstawie podobnych zasad oraz opierają się na obserwacji naprężeń, odkształceń i przemieszczeń wielowymiarowej informacji, w celu zrozumienia zjawiska mechanicznego i prawa stanu naprężeń i przemieszczeń na prototypie, aby osiągnąć cel realizacji geotechnicznego projektowania i budowy. Z uwagi na praktyczne, zaawansowane przemieszczenie w przedniej części tunelu oraz przemieszczenie samej powierzchni tunelu, pomiary są trudne do przeprowadzenia za pośrednictwem monitorowania. Możemy prowadzić skuteczną analizę i dyskusję dotyczącą słabej/uszkodzonej skały otaczającej przy użyciu podobnej geometrycznej metody badania modelu. Jednakże, badania modelu zależą od wielu czynników w rzeczywistym procesie zastosowania, przez co trudno jest osiągnąć pożądany efekt. Wśród nich, technologia pozyskiwania licznych informacji na temat dynamicznego monitorowania procesu badania stała się ważnym czynnikiem, ograniczającym rozwój geometrycznej metody badań modelu. Jak wiemy, mnogość informacji geometrycznej na temat metody badań modelu obejmuje napięcie, naprężenie, ciśnienie, przemieszczenie, itp. Mnogość informacji w procesie budowy tunelu, takich jak dynamiczne monitorowanie pierwszego przemieszczenia, przemieszczenie i tylne przemieszczenie powierzchni tunelu, jest rzadko analizowana. Jednakże, pomyślne zdobycie licznych informacji podczas budowy tunelu jest kluczem do sukcesu w badaniu modelu. Dlatego też, w celu zbadania systemu monitorowania wielu informacji w procesie budowy tunelu, należy uchwycić stan przekształcenia i naprężenia, jak również zwiększyć dokładność pomiarów i nie ma wątpliwości co do pełnego wykorzystania zalet technologii badań modelu. Na podstawie techniki monitorowania światłowodu, różnorodny zbiór informacji dla systemu monitorowania jest tworzony jako rdzeń systemu dynamicznego monitorowania światłowodu w czasie rzeczywistym. W połączeniu z wysokoprecyzyjnym mechanicznym i mikroprzemieszczającym miernikiem o typie kraty i innymi środkami, zgodnie z wymogami pomiarów badania modelu, system monitorowania licznych informacji został opracowany i skutecznie wykorzystany w procesie budowy tunelu. Wyniki badania modelu pokazują, że system może być stosowany do monitorowania procesu budowy tunelu, a ponadto jest zdolny do wychwytywania drobnych zmian i wartości fluktuacji komunikatów wielojednostkowych, jak również do tworzenia podwaliny dla powodzenia badania modelu.

12

Lignite cleaning in NaCl solutions by the reverse flotation technique

Zhang H., Liu Q.

Physicochemical Problems of Mineral Processing

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2015

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Vol. 51, iss. 2

695--706

EN

A cleaning possibility of low (BD) and high ash content (IM) lignites in NaCl solutions using a reverse flotation technique was studied. Preliminary test results indicated that BD lignite cannot be cleaned effectively in the traditional manner because gangue was floated first rather than a combustible material. Further studies indicated that the lignite cleaning in NaCl solutions using the reverse flotation technique is possible. However, a large quantity of dodecyl amine hydrochloride (DAH) was required. A lower ash content in a concentrate can be obtained by addition of NaCl. A concentrate yield can be im-proved by addition of starch. Under the test conditions, for BD lignite with the ash content in the feed 15.19%, the ash content in the concentrate 11.44% and the concentrate yield 67.38% were obtained. Similarly, for IM lignite with the ash content in the feed 57.40%, the ash content in the concentrate 32.90% and the concentrate yield 25.08% were obtained. The flotation rate constant k and maximum ash recovery ε∞ significantly increased with the NaCl concentration.

13

Optimal quasi-periodic preventive maintenance policies for a repairable system with stochastic maintenance interval

Gao W., Zhang Z., Ji H., Zhou Y., Liu Q.

Eksploatacja i Niezawodność

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2015

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Vol. 17, no. 3

389--397

EN

The usual preventive maintenance (PM) of a repairable system is done before failure at integer multiples of time T. In some real cases, PM cannot be performed as soon as a planned PM period is reached because of effects of some random factors, while it is usually done within an implemented period, and thus it makes the PM period become a stochastic interval. From this viewpoint, a quasi-periodic imperfect preventive maintenance policy is proposed in this paper, in which a repairable system experiences either a minor failure or catastrophic failure when a failure occurs, and the first (N-1) PM intervals is divided into a planned PM period and an implemented period. In the former, the system may be suffered an unplanned PM for removing a catastrophic failure and performing a PM, whereas in the latter, the system is preventively maintained following an occurrence of a catastrophic failure or a dynamic PM plan, whichever comes first. At the Nth PM interval, the system is replaced either when a catastrophic failure occurs or operational time reaches T, whichever comes first. An optimization of the proposed mode is introduced, the existence and the uniqueness of the optimal solution are presented, and a useful constraint of the implemented period is obtained. Finally, a real case study of PM on Chinese diesel locomotives is examined to illustrate the proposed maintenance policy.

PL

Zazwyczaj przeglądy okresowe systemu naprawialnego wykonuje się przed wystąpieniem uszkodzenia, w określonych odstępach czasu stanowiących całkowitą wielokrotność czasu T. W warunkach rzeczywistych, jednak, nie zawsze można przeprowadzić przegląd w zaplanowanym terminie ze względu na działanie pewnych losowych czynników, natomiast zazwyczaj przeprowadza się go w dopuszczalnym okresie realizacji, w związku z czym przedział czasu między przeglądami okresowymi staje się wielkością stochastyczną. Biorąc powyższe pod uwagę, w niniejszej pracy zaproponowano strategię quasi-okresowej konserwacji zapobiegawczej, która zakłada, że system naprawialny może ulec albo drobnemu uszkodzeniu albo uszkodzeniu katastroficznemu, a czas, do którego należy wykonać pierwszy przegląd okresowy (N-1) można podzielić na zaplanowany czas przeprowadzenia przeglądu oraz dopuszczalny okres realizacji przeglądu. W pierwszym przypadku, może wystąpić konieczność przeprowadzenia nieplanowanej konserwacji systemu mającej na celu usunięcie uszkodzenia katastroficznego, natomiast w drugim, konserwację przeprowadza się po wystąpieniu uszkodzenia katastroficznego lub zgodnie z dynamicznym harmonogramem przeglądów, zależnie od tego, która z sytuacji zaistnieje wcześniej. W N-tym terminie przeglądu okresowego, dokonuje się wymiany systemu, albo wskutek wystąpienia uszkodzenia katastroficznego albo gdy czas pracy systemu osiągnie wartość T, zależnie od tego, co nastąpi wcześniej. W artykule przedstawiono optymalizację proponowanego trybu działania, wykazano istnienie i jednoznaczność optymalnego rozwiązania oraz wyznaczono przydatne ograniczenie dopuszczalnego okresu realizacji. Na koniec, proponowaną politykę konserwacji zapobiegawczej zilustrowano studium przypadku chińskich lokomotyw spalinowych.

14

Analysis of Fructus Arctii from Different Regions of China by HPLC Coupled with Chemometrics Methods

Liu Q., Qin K., Shen B., Cai H., Cai B.

Acta Chromatographica

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2015

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Vol. 27, no. 4

697--709

EN

To evaluate the quality of Fructus Arctii, an accurate and reliable method of high-performance liquid chromatography/diode array detection—electrospray ionization—mass spectrometry (HPLC/DAD—ESI—MS) was developed. Nine compounds, including chlorogenic acid, caffeic acid, trans-p-hydroxycinnamic acid, arctiin, arctignan A, ethyl caffeate, matairesinol, arctigenin, and lappaol B, were determined simultaneously in 19 batches of Fructus Arctii samples collected from different localities. Nineteen common peaks were identified or tentatively assigned by comparing their mass spectrometric data with reference compounds, self-established compound library, and published literatures. Also, the 19 common peaks were selected as characteristic peaks to assess the similarity of chromatographic fingerprinting of these samples. Moreover, hierarchical clustering analysis (HCA) and principal components analysis (PCA) were successfully applied to demonstrate the variability of samples. The results indicated the content of nine compounds that varied greatly among the samples, and 19 samples collected from different localities could be discriminated. Furthermore, chlorogenic acid, arctiin, and arctigenin were found to be chemical markers for evaluating the quality of Fructus Arctii.

15

Using a vision cognitive algorithm to schedule virtual machines

Zhao J., Mhedheb Y., Tao J., Jrad F., Liu Q., Streit A.

International Journal of Applied Mathematics and Computer Science

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2014

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Vol. 24, no. 3

535--550

EN

Scheduling virtual machines is a major research topic for cloud computing, because it directly influences the performance, the operation cost and the quality of services. A large cloud center is normally equipped with several hundred thousand physical machines. The mission of the scheduler is to select the best one to host a virtual machine. This is an NP-hard global optimization problem with grand challenges for researchers. This work studies the Virtual Machine (VM) scheduling problem on the cloud. Our primary concern with VM scheduling is the energy consumption, because the largest part of a cloud center operation cost goes to the kilowatts used. We designed a scheduling algorithm that allocates an incoming virtual machine instance on the host machine, which results in the lowest energy consumption of the entire system. More specifically, we developed a new algorithm, called vision cognition, to solve the global optimization problem. This algorithm is inspired by the observation of how human eyes see directly the smallest/largest item without comparing them pairwisely. We theoretically proved that the algorithm works correctly and converges fast. Practically, we validated the novel algorithm, together with the scheduling concept, using a simulation approach. The adopted cloud simulator models different cloud infrastructures with various properties and detailed runtime information that can usually not be acquired from real clouds. The experimental results demonstrate the benefit of our approach in terms of reducing the cloud center energy consumption.

16

Separation and analysis of phenylethanoid glycosides in Lamiophlomis rotata by high-performance liquid chromatography

Dong S., Shi X., Liu Q., Zhang Z., Zhao L.

Acta Chromatographica

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2013

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Vol. 25, no. 2

377--392

EN

A simple hydrolysis method has been developed for determination of phenylethanoid glycosides in Lamiophlomis rotata (L.R.). Different kinds of phenylethanoid glycosides were hydrolyzed in hydrochloric acid solution to produce corresponding phenethyl alcohols and cinnamic acids, mainly containing hydroxytyrosol, homovanillyl alcohol, 3,4-dimethoxyphenethyl alcohol, caffeic acid, fumalic acid and 3,4-dimethoxycinnamic acid. The six analytes could be determined simultaneously by high-performance liquid chromatography (HPLC). The effects of mobile phase, pH and concentration of running buffer, detection wavelength, flow rate and injection volume were also investigated. Under the optimum conditions, the six hydrolyzates could be perfectly separated within 45 min. The response was linear over four orders of magnitude with detection limits (S/N = 3) ranging from 1 × 10 -8 to 1.5 × 10-4 mol L-1 for the analytes. The method has been successfully applied to the analysis of real sample Du-Yi-Wei capsule and Qi-Zheng-Yan-Tong patch, with satisfactory results.

17

Denoising and detrending of measured oscillatory signal in power system

Yang D., Rehtanz C., Li Y., Liu Q., Görner K.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 3b

135-139

EN

This paper presents a novel method for denoising and detrending of oscillatory signal measured from wide area measurement system (WAMS) using empirical mode decomposition (EMD) and time-frequency analysis. First of all, the measured signal is decomposed into a set of intrinsic mode functions (IMFs) by EMD. Next, the IMFs are divided into three parts based on their time and frequency distributions. Then, the noise and higher frequency components, trend components and meaningful oscillation modes are identified respectively. The proposed method are validated by the actual measured signal from WAProtector and the estimated trend is confirmed by comparing with the sliding linear trend estimated method and other nonlinear trend estimated methods.

PL

W artykule zaprezentowano nową metodę usuwania szumu z sygnału okresowego w systemach WAMS. W pierwszej kolejności przeprowadza się dekompozycję sygnału na funkcje, które następnie dzielone są na trzy części w zależności od rozkładu czasowoczęstotliwościowego.

18

3-aminopropyltriethoxysilane functionalized nanoscale zero-valent iron for the removal of dyes from aqueous solution

Zhang J., Liu Q., Ding Y., Bei Y.

Polish Journal of Chemical Technology

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2011

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Vol. 13, nr 2

35-39

EN

Batch studies were conducted to investigate the potential of 3-aminopropyltriethoxysilane modified nano zero-valent iron (APS-NZVI) to adsorb two dyes (acid brilliant scarlet GR and reactive brilliant red K-2BP) from aqueous solution. APS-NZVI showed good adsorption performance for two dyes. Under the adsorption conditions of pH 4.5, initial concentration was 100 mg/L, and time=4h, the maximum adsorption capacities of APS-NZVI were 121.06 mg/g for acid brilliant scarlet GR and 191.5 mg/g for reactive brilliant red K-2BP, respectively. The results revealed that the adsorption behavior of the dyes on the nano-particles fitted well with the Langmuir model and the sorption kinetics fits well the pseudo-second-order rate equation.

19

Model badania potwierdzającego niezawodność dla dwumianowych systemów o rosnącej niezawodności

Wu X., Liu Q.

Eksploatacja i Niezawodność

|

2010

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nr 2

55-58

PL

Wiele złożonych systemów inżynieryjnych przechodzi proces wzrostu niezawodności w kolejnych etapach badań. Większość istniejących modeli badań potwierdzających niezawodność nie uwzględnia jednak wzrostu niezawodności. W niniejszym artykule przedstawiono model badania niezawodności dla systemów dwumianowych o 2 etapach testowych, który bierze pod uwagę możliwy wzrost niezawodności. Określono wskaźniki prawdopodobieństwa dla różnych możliwych sytuacji oraz wyprowadzono statystyczne reguły decyzyjne. Podany przykład ilustruje względnie niższe ryzyko decyzyjne proponowanego modelu w stosunku do tego, jakie niosą klasyczne modele badań.

EN

Many complex engineering systems experience reliability growth in successive test stages. In most existing reliability demonstration test models, reliability growth is not incorporated. In this paper, for binomial systems with 2 test stages, a reliability demonstration test model is presented that takes possible reliability growth into consideration. Likelihood ratios are defi ned for various possible situations, and statistical decision rules are derived. With a given example, the relative lower decision risk of the proposed model is illustrated by comparison with that of classical demonstration test models.

20

Photosynthetic and physiological responses of Swida hemsleyi (C.K. Schneid. et Wangerin) Sojak (Cornaceae) subjected to enhanced UV-B radiation and to nitrogen supply

Yao X., Liu Q.

Polish Journal of Ecology

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2009

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Vol. 57, nr 3

483-494

EN

Atmospheric ozone remains depleted which in turn leads to the increase of UV-B radiation reaching the surface of the earth and in the same time more and more nitrogen will be imported into the terrestrial ecosystems through nitrogen deposition. These two factors will operate simultaneously. The photosynthetic and physiological responses of deciduous broad leaved species Swida hemsleyi occurring commonly at 1350-3700 m a.s.l. subjected to enhanced UV-B and to nitrogen supply were studied. The experimental design included two levels of UV-B treatments (ambient UV-B, 11.02 KJ m[^-2] day[^-1] and enhanced UV-B, 14.33 KJ m[^-2] day[^-1] and two nitrogen levels (without supplemental nitrogen supply and with supplemental nitrogen supply). An experiment was conducted in open semi-field condition in Maoxian Ecological Station of Chinese Academy of Sciences, Sichuan province, China at 1820 m a.s.l. Enhanced UV-B caused a marked decline in growth parameters, net photosynthetic rate, stomatal conductance to water vapour, chlorophyll pigments, whereas it induced an increase in rate of reactive oxygen species (ROS) production and ROS accumulation and malondialdehyde (MDA) content. Enhanced UV-B also induced an increase in leaf thickness and antioxidant compounds content, such as carotenoids and proline content. On the other hand, nitrogen supply caused an increase in some growth parameters, chlorophyll pigments and antioxidant compounds, and reduced ROS accumulation. However, nitrogen supply did not affect MDA content under enhanced UV-B, though it increased antioxidant compounds content and reduced the rate of ROS production and ROS accumulation. These results implied that enhanced UV-B brought harmful effects on Swida hemsleyi seedlings and supplemental nitrogen supply could alleviate the adverse effects of UV-B radiation on plants to some extent.