Wyniki wyszukiwania - BazTech

1

Badania nad Radix Sophorae Subprostratae za pomocą techniki nieliniowych fingerprintów chemicznych (pełne spektrum)

Ding F., She Y., Fang X., Li S., Liang Y., Zhang T., Si S.

Przemysł Chemiczny

|

2018

|

T. 97, nr 11

1884--1888

PL

Technika nieliniowego chemicznego fingerprintu NCF (non-linear chemical fingerprint) może być z powodzeniem stosowana do kompleksowej oceny układów złożonych. NCF wykorzystano do badania korzenia rośliny Sophorae Subprostratae ( Sophora subprostrata Chun et T. Chen), stosowanego w tradycyjnej medycynie chińskiej. W badaniach uwzględniono parametr jakościowy i parametr ilościowy reakcji (czas i potencjał) oraz ustalono matematyczną zależność pomiędzy nimi. W układzie oscylacyjnym złożonym z bromianu sodu, kwasu siarkowego, acetonu i siarczanu manganu optymalny zakres detekcji składników Radix Sophorae Subprostratae uzyskano dla ilości 0,7-1,5 g sproszkowanego korzenia. Wykazano pewne różnice w chemicznym składzie próbek Radix Sophorae Subprostratae pozyskanych z różnych regionów. Uzyskane wyniki porównano z wynikami analizy chromatograficznej.

EN

Radix Sophorae Subprostratae (traditional Chinese medicine) was evaluated in a fixed system consisting of NaBrO3, H2SO4, Me2CO and MnSO4 do det. its fingerprint. Three oscillation areas were established. The results agreed with chromatog. detd. data.

2

Double-layer microwave absorber based on nanocrystalline CoFe2O4 and CoFe2O4/PANI multi-core/shell composites

Xu Y., Shen G., Wu H., Liu B., Fang X., Zhang D., Zhu J.

Materials Science Poland

|

2017

|

Vol. 35, No. 1

94--104

EN

Organic-inorganic nano-CoFe2O4/PANI (polyaniline) multi-core/shell composites have been successfully synthesized by chemical oxidative polymerization of aniline. The characterization results showed that the ferrite nanocrystals were efficiently embedded in PANI. The electromagnetic parameters of the composites were measured by a vector network analyser in the frequency range of 2 GHz to 18 GHz. Double-layer absorbers based on the CoFe2O4/PANI composite (matching layer) and calcined CoFe2O4 ferrite (absorbing layer) have been designed. The reflection loss of the microwave absorbers of both single layer and double-layer with a total thickness of 2.0 mm and 2.5 mm was calculated according to transmission-line theory. The results indicated that the minimum reflection loss of the CoFe2O4/PANI composite was −19.0 dB at 16.2 GHz at the thickness of 2.0 mm and −23.6 dB at 13.1 GHz at the thickness of 2.5 mm, respectively. The minimum reflection loss for double-layer absorbers reached −28.8 dB at 16.2 GHz at the total thickness of 2.0 mm, and −31.1 dB at 12.8 GHz at the total thickness of 2.5 mm. The absorption bandwidth under −10 dB was 4.2 GHz (13.8 GHz to 18.0 GHz) and 5.5 GHz (10.3 GHz to 15.8 GHz), respectively. The results show that the reflection loss and absorption bandwidth of the double-layer absorbers are obviously enhanced compared to corresponding single layer absorbers.

3

Lifetime prediction of self-lubricating spherical plain bearings based on physics-of-failure model and accelerated degradation test

Wang Y., Fang X., Zhang C., Chen X., Lu J.

Eksploatacja i Niezawodność

|

2016

|

Vol. 18, no. 4

528--538

EN

Due to small friction coefficient and no need for lubrication during operation, self-lubricating spherical plain bearings (SSPBs) have been widely used in operation and transmission systems in aerospace, nuclear power plants, and ship equipment and they are key components of these systems. SSPBs failure will directly affect the operational reliability and safety of the equipment; therefore, it is necessary to accurately predict the service life of SSPBs to define reasonable maintenance plans and replacement cycles and to ensure reliability and safety of vital equipment. So far, lifetime prediction of SSPB has been primarily based on empirical formulae established by most important bearing manufacturers. However, these formulae are lack of strong theoretical basis; the correction coefficients are difficult to determine, resulting in low accuracy of lifetime prediction. In an accelerated degradation test (ADT), the load is increased to accelerate the SSPB wear process. ADT provides a feasible way for accurate lifetime prediction of SSPB in a short period. In this paper, wear patterns are studied and methods of wear analysis are presented. Then, physics-offailure model which considers SSPB wear characteristics, structure parameters and operation parameters is established. Moreover, ADT method for SSPB is studied. Finally, lifetime prediction method of SSPBs based on physics-of-failure model and ADT is established to provide a theoretical method for quick and accurate lifetime prediction of SSPBs.

PL

W związku z niskim współczynnikiem tarcia oraz brakiem konieczności smarowania podczas pracy,samosmarujące łożyska ślizgowe (self-lubricating spherical bearings, SSPB) znajdują szerokie zastosowanie w układach pracy oraz układach przełożeń urządzeń w przemyśle lotniczym, elektrowniach jądrowych, oraz na statkach, stanowiąc kluczowe elementy tych układów. Uszkodzenie łożyska SSPB ma bezpośredni wpływ na niezawodność eksploatacyjną oraz bezpieczeństwo sprzętu; dlatego też istnieje konieczność precyzyjnego prognozowania resursu łożysk SSPB, pozwalającego na odpowiednie planowanie konserwacji oraz cykli wymiany , które ma na celu zapewnienie niezawodności i bezpieczeństwa kluczowego sprzętu. Dotychczas czas pracy łożysk SSPB prognozowano przede wszystkim w oparciu o wzory empiryczne podawane przez największych producentów łożysk. Wzory te, jednak, nie mają solidnej podstawy teoretycznej; trudno jest dla nich określić współczynniki korygujące, co zmniejsza trafność prognozowania czasu pracy. W przyspieszonych badaniach degradacji zwiększa się obciążenie celem przyspieszenia procesu zużycia łożysk SSPB. Badania przyspieszone umożliwiają trafne przewidywanie czasu pracy łożysk SSPB w krótkim okresie czasu. W przedstawionej pracy analizowano wzorce zużycia badanych łożysk oraz przedstawiono metody analizy zużycia. Następnie opracowano model fizyki uszkodzeń, który uwzględnia charakterystyki zużycia, parametry konstrukcyjne oraz parametry eksploatacyjne omawianych łożysk ślizgowych. Ponadto rozpatrywano możliwość zastosowania badań przyspieszonych dla tego typu łożysk. W wyniku przeprowadzonych badań, opracowano metodę prognozowania czasu pracy łożysk SSPB opartą na modelu fizyki uszkodzeń oraz badaniach przyspieszonych, która pozwala na szybkie i trafne prognozowanie czasu pracy samosmarujących łożysk ślizgowych.

4

Laser Ignition of an Optically Sensitised Secondary Explosive by a Diode Laser

Fang X., Ahmad S. R.

Central European Journal of Energetic Materials

|

2016

|

Vol. 13, no. 1

103--115

EN

As a green technology, laser ignition of a relatively insensitive secondary explosive has been experimentally investigated. The explosive, hexanitrostilbene (HNS), was doped with one of two optical sensitizers, carbon black or a laser absorbing dye, and a continuous-wave (CW) infrared diode laser was used as the igniting source. The ignition sensitivities of HNS with each of the two optical sensitizers were analysed and compared in terms of: optical power threshold for ignition, ignition delay and full burn delay at various laser powers. The results have shown that both the chemical dye and carbon black optically sensitize the explosive with similar efficiencies. In contrast to the carbon black, the dye provides wavelength specificity and selectivity in the laser ignition process and its solubility in some specific solvents improves the coating of the explosive material. It was therefore concluded that the laser absorbing dye is a better candidate for optical sensitization in laser ignition than the commonly used carbon black. The combination of laser ignition sensitivity with wavelength selectivity potentially offers higher reliability and safety at a low optical power for future ignitors of secondary explosives.

5

Influence of Processing Techniques on Mechanical Properties and Impact Initiation of an Al-PTFE Reactive Material

Feng B., Fang X., Li Y.-C., Wu S.-Z., Mao Y.-M., Wang H.-X.

Central European Journal of Energetic Materials

|

2016

|

Vol. 13, no. 4

989--1004

EN

Reactive materials (RMs) or impact-initiated materials have received much attention as a class of energetic materials in recent years. To assess the influence of processing techniques on mechanical properties and impact initiation behaviors of an Al-PTFE reactive material, quasi -static compression tests and drop-weight tests were performed. Scanning electron microscopy (SEM) was used to identify the characteristics of the interior microstructures of the Al-PTFE samples. A sintering process was found to transform Al-PTFE from a brittle to a ductile material with an increased elasticity modulus (from 108-160 MPa to 256-336 MPa) and yield stress (from 12-16 MPa to 19-20 MPa). Increasing the molding pressure from 36 MPa to 182 MPa increased the elastic modulus of all Al-PTFE samples and also the yield stress of unsintered ones. Unsintered samples in general required less energy to initiate than sintered ones. As the molding pressure increased, the impact initiation energy for sintered Al-PTFE fell from 96 J to 68 J, whereas the initiation energy for unsintered Al-PTFE rose from 68 J to 85 J. PTFE nanofiber networks observed in sintered samples formed under the higher molding pressures could contribute to the opposite trends observed in the impact initiation energy of unsintered and sintered Al-PTFE samples.

6

Behavior Consistency Analysis Based on the Behavior Profile about Transition Multi-Set of Petri Net

Fang X., Wang M., Yin Z.

Przegląd Elektrotechniczny

|

2013

|

R. 89, nr 1b

171--173

EN

Duplicate activities often appear in the business process modeling, analyzing the consistency of corresponding model containing duplicate activities is a problem , the existing behavior consistency methods can not analyze effectively the process model with the multi-set of transition. In the paper, by analyzing of three kinds of weak order relations of multi set of transition, a kind of consistency measure methods based on behavior profile of multi-sets of transitions of Petri net is proposed. Finally , an example is given out, which shows the method is effective.

PL

W artykule przedstawiono metodę określenia regularności związków słabych w systemie wielowątkowym o powielających się danych. Analiza, trzech wybranych rodzajów relacji oparta została na profilu wielowątkowej sieci Petriego. Opisano także przykład, potwierdzający skuteczność działania.

7

Weyl's theorem for algebraically k-quasiclass a operators

Gao F., Fang X.

Opuscula Mathematica

|

2012

|

Vol. 32, no. 1

125-135

EN

If T or T* is an algebraically k-quasiclass A operator acting on an infinite dimensional separable Hilbert space and F is an operator commuting with T, and there exists a positive integer n such that Fn has a finite rank, then we prove that Weyl's theorem holds for ∫ (T)+F for every ∫∈ H(σ (T)), where H(σ (T)) denotes the set of all analytic functions in a neighborhood of σ (T). Moreover, if T* is an algebraically k-quasiclass A operator, then α-Weyl's theorem holds for ∫(T). Also, we prove that if T or T* is an algebraically k-quasiclass A operator then both the Weyl spectrum and the approximate point spectrum of T obey the spectral mapping theorem for every ∫∈ H(σ (T)).

8

Effect of minor Cu addition on the precipitation sequence of an as-cast Al-Mg-Si 6005 alloy

Li K., Song M., Du Y., Fang X.

Archives of Metallurgy and Materials

|

2012

|

Vol. 57, iss. 2

458-466

EN

The whole precipitation sequences of two as-cast Al-Mg-Si 6005 alloys (containing no Cu or 0.1 wt.% Cu) at 150 degree Celsjus were investigated using X-ray diffraction, transmission electron microscopy and hardness examinations. The precipitation sequence of the Cu-free alloy can be expressed as: super-saturated solid solution (SSSS) → spherical G.P. zones → pre - β'' → β'' → U2 +Si + β x → Si + β β xwhile that of the Cu-containing alloy can be expressed as: SSSS → spherical G.P. zones + platelet-like G.P. zones → pre - β → β'' → Q' + β + Si → Q + β + Si. A new type of βprecipitate, namely β x here, has been discovered in the Cu-free alloy. The addition of minor Cu is found to accelerate the microstructural evolution by inducing the formation of a new type of platelet-like G.P. zone along {111} Al planes, and improve the hardening response at the over-aged stage by forming Q' and Q precipitates.

PL

Kompletna sekwencja wydzieleń dwóch odlanych stopów Al-Mg-Si 6005 (zawierąjacych 0 i 0.1%.wag Cu), w temperaturze 150 stopni Celsjusza, została zbadana przy użyciu dyfrakcji rentgenowskiej, transmisyjnej mikroskopii elektronowej i badań twardości. Sekwencja wydzieleń w stopie nie zawierającym Cu może być przedstawiona następująco: przesycony roztwór stały → sferyczne strefy Guiniera-Prestona → pre - β'' → β'' → U2 +Si + β x → Si + β β x natomiast dla stopu zawierającego Cu następująco: przesycony roztwór stały → sferyczne i płytkowe strefy Guiniera-Prestona → pre - β → β'' → Q' + β + Si → Q + β + Si. Nowy rodzaj wydzieleń β, tj. β x , został odkryty w stopie niezawierajacym Cu. Stwierdzono, że dodatek niewielkiej ilości Cu przyspiesza zmiany mikrostruktury poprzez indukowanie tworzenia nowego typu płytkowych stref Guiniera-Prestona wzdłuż płaszczyzny {111}Al. i poprawia utwardzenie poprzez tworzenie wydzieleń Q' i Q.

9

Forecasting carbon budget under climate change and CO2 fertilization for subtropical region in China using Integrated Biosphere Simulator (IBIS) model

Zhu Q., Jiang H., Liu J., Peng C., Fang X., Yu S., Zhou G., Wei X., Ju W.

Polish Journal of Ecology

|

2011

|

Vol. 59, nr 1

3-23

EN

The regional carbon budget of the climatic transition zone may be very sensitive to climate change and increasing atmospheric CO2 concentrations. This study simulated the carbon cycles under these changes using process-based ecosystem models. The Integrated Biosphere Simulator (IBIS), a Dynamic Global Vegetation Model (DGVM), was used to evaluate the impacts of climate change and CO2 fertilization on net primary production (NPP), net ecosystem production (NEP), and the vegetation structure of terrestrial ecosystems in Zhejiang province (area 101,800 km2, mainly covered by subtropical evergreen forest and warm-temperate evergreen broadleaf forest) which is located in the subtropical climate area of China. Two general circulation models (HADCM3 and CGCM3) representing four IPCC climate change scenarios (HC3AA, HC3GG, CGCM-sresa2, and CGCM-sresb1) were used as climate inputs for IBIS. Results show that simulated historical biomass and NPP are consistent with field and other modelled data, which makes the analysis of future carbon budget reliable. The results indicate that NPP over the entire Zhejiang province was about 55 Mt C yr[^-1] during the last half of the 21st century. An NPP increase of about 24 Mt C by the end of the 21st century was estimated with the combined effects of increasing CO2 and climate change. A slight NPP increase of about 5 Mt C was estimated under the climate change alone scenario. Forests in Zhejiang are currently acting as a carbon sink with an average NEP of about 2.5 Mt C yr[^-1]. NEP will increase to about 5 Mt C yr[^-1] by the end of the 21st century with the increasing atmospheric CO2concentration and climate change. However, climate change alone will reduce the forest carbon sequestration of Zhejiang.s forests. Future climate warming will substantially change the vegetation cover types; warm-temperate evergreen broadleaf forest will be gradually substituted by subtropical evergreen forest. An increasing CO2 concentration willhave little contribution to vegetation changes. Simulated NPP shows geographic patterns consistent with temperature to a certain extent, and precipitation is not the limiting factor for forest NPP in the subtropical climate conditions. There is no close relationship between the spatial pattern of NEP and climate condition.

10

Fisher’s linear discriminant (FLD) and support vector machine (SVM) in non-negative matrix factorization (NMF) residual space for face recognition

Zhou C., Wei X., Zhang Q., Fang X.

Optica Applicata

|

2010

|

Vol. 40, nr 3

693--704

EN

A novel method of Fisher’s linear discriminant (FLD) in the residual space is put forward for the representation of face images for face recognition, which is robust to the slight local feature changes. The residual images are computed by subtracting the reconstructed images from the original face images, and the reconstructed images are obtained by performing non-negative matrix factorization (NMF) on original images. FLD is applied to the residual images for extracting FLD subspace and the corresponding coefficient matrices. Furthermore, features are obtained by mapping the residual image to FLD subspace. Finally, the features are utilized to train and test support vector machines (SVMs) for face recognition. The computer simulation illustrates that this method is effective on the ORL database and the extended Yale face database B.