Wyniki wyszukiwania - Biblioteka Nauki

1

Lifetime Distribution and Associated Inference of Systems with Multiple Degradation Measurements Based on Gamma Processes

100%

Pan Z. , Feng J. , Sun Q.

Eksploatacja i Niezawodność

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2016

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tom Vol. 18, no. 2

307--313

EN

With development of science and technology, many engineering systems take on high reliable characteristic and usually have complex structure and failure mechanisms, with their reliability being evaluated by multiple degradation measurements. In certain physical situations, the degradation of these performance characteristics would be always positive and strictly increasing. Therefore, the gamma process is usually considered as a degradation process due to its independent and non-negative increments properties. In this paper, we suppose that a system has multiple dependent performance characteristics and that their degradation can be modeled by gamma processes. For such a multivariate degradation involving three or more performance characteristics, we propose to use a multivariate Birnbaum-Saunders distribution and its marginal distributions to approximate the reliability function and give the corresponding lifetime distribution. And then, the inferential method for the model parameters is developed. Finally, for an illustration of the proposed model and method, a simulated example is discussed and some computational results are presented.

PL

Wraz z rozwojem nauki i techniki, powstaje coraz więcej systemów inżynieryjnych o wysokich parametrach niezawodnościowych, które zwykle charakteryzują się złożoną strukturą i złożonymi mechanizmami uszkodzeń. Ocena niezawodności w przypadku takich systemów wymaga pomiarów współwystępujących procesów degradacji . W pewnych sytuacjach fizycznych, degradacja właściwości użytkowych systemu będzie zawsze dodatnia oraz ściśle rosnąca. Proces degradacji jest zwykle procesem gamma, który charakteryzują niezależne i nieujemne przyrosty. W niniejszej pracy, założono, że system ma wiele zależnych charakterystyk pracy oraz że ich degradację można modelować procesem gamma. W przypadkach takiej wielowymiarowej degradacji obejmującej trzy lub więcej charakterystyk pracy zaproponowano zastosowanie rozkładu Birnbauma-Saundersa (uwzględniającego wiele zmiennych) oraz jego rozkładów brzegowych do aproksymacji funkcji niezawodności oraz określania odpowiadającego jej rozkładu czasu pracy. Opracowano metodę wnioskowania dla parametrów modelu. Wreszcie, dla zilustrowania proponowanego modelu oraz metody, omówiono przykład symulacyjny oraz przedstawiono niektóre wyniki obliczeniowe.

2

Postnatal growth and age estimation in big-footed myotis, Myotis macrodactylus

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Liu Y. , Jin L.-R. , Metzner W. , Feng J.

Acta Chiropterologica

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2009

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tom 11

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nr 1

EN

We quantified the length of the forearm, the body mass and the length of the total gap of the fourth metacarpal-phalangeal joint of marked individuals of big-footed myotis bats (Myotis macrodactylus) from birth to flight in Dalazi Cave in Ji’an, Jilin Province, China. By using these data, we develop empirical growth curves, derive growth rates, establish age-predictive equations, and compare growth parameters based on three nonlinear growth models. Neonates of M. macrodactylus were bom within a half-month period, with length of forearm averaging ca. 38.4% of the size of adult females and body mass averaging ca. 39.6% of their mother’s body mass. Length of forearm increased linearly until 14 days after birth (growth rate = 1.20 mm/day), as did body mass until 11 days after birth (growth rate = 0.32 g/day). The length of the total gap of the fourth metacarpal-phalangeal joint decreased linearly from 13 days to 45 days of birth. Two most appropriate linear regression equations predicting the age of young bats were derived from forearm length (x̅ ± SE) from 15.35 ± 0.96 mm to 33.24 ± 1.87 mm and the length of the epiphyseal gap from 13 to 45 days. These two equations make it possible to estimate the age of pups from 1 to 45 days of age in M. macrodactylus. Of the three nonlinear growth models (logistic, Gompertz, and von Bertalanffy), the logistic equation provides the best fit to the empirical curves for length of forearm and body mass.

3

A new mouse-eared bat (Mammalia: Chiroptera, Vespertilionidae) from South China

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Tiunov M. P. , Kruskop S. V. , Feng J.

Acta Chiropterologica

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2011

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tom 13

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nr 2

EN

A small Myotis species belonging to the Myotis siligorensis group was found in four caves in Yunnan province, South China. Twenty specimens of this bat were compared with other East Asian Myotis species. Statistical and physical analysis of this sample demonstrates that, despite their similarity to M. siligorensis, the Yunnan specimens have characteristics of baculum morphology and cranial proportions suggesting that they represent a distinct species.

4

Wear properties of hemp, ramie and linen fabrics after liquid ammonia/crosslinking treatment

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Li J. , Feng J. , Zhang H. , Zhang J.

Fibres & Textiles in Eastern Europe

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2010

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tom Vol. 18, no. 5 (82)

81--85

EN

Desized and scoured hemp, ramie and linen fabrics were treated with liquid ammonia over practical ranges, followed by crosslink finishing with modified DMDHEU (Clariant Chemical Co). Appearance qualities, as well as comfort and mechanical properties were measured to investigate the wear behavior of all-cellulosic fabrics. The crease recovery, washing shrinkage and other appearance qualities of cellulosic fabrics were improved by NH3 treatment and especially by liquid ammonia pretreatment in conjunction with crosslink finishing. The moisture regain of the cellulosic fibers was increased by NH3 treatment, but on the other hand, water retention was decreased. The air permeability, moisture permeability and other comfort properties of the cellulosic fabrics were decreased by crosslink finishing, whereas those of NH3/crosslinked fabrics were greater than untreated ones. As a pretreatment for crosslink finishing, liquid ammonia significantly improved the tensile strength retention and tear strength in cellulosic fabrics compared to crosslink finishing alone.

PL

Tkaniny z konopi, ramii oraz lnu po usunięciu klejonki i odtłuszczeniu obrabiano ciekłym amoniakiem i sieciowano DMDHEU (Clariant Chemical Co). W celu określenia zachowania podczas użytkowania tkanin z włókien celulozowych oceniano ich wygląd oraz właściwości mechaniczne. Obróbka NH3 i wstępne działanie ciekłym azotem w połączeniu z sieciowaniem poprawiły odporność tkaniny na gniecenie, kurczliwość po praniu oraz inne cechy wyglądu tkanin. Absorpcja włókien celulozowych wzrosła po obróbce NH3, ale z innej strony, spadła retencja wody. Po sieciowaniu pogorszyła się przepuszczalność powietrza i wilgoci, a także inne właściwości użytkowe tkanin, podczas gdy te same cechy tkanin obrabianych NH3 i sieciowanych były lepsze niż tkanin nie obrabianych. Poprzedzenie sieciowania obróbką ciekłym amoniakiem znacząco polepsza wytrzymałość w porównaniu do tkanin poddanych samemu sieciowaniu.

5

Niewidzialne światy

100%

Feng J. , Trodden M.

Świat Nauki

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2010

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nr 12

6

Accurate measurements and establishment of a model of the mechanical properties of dried corn kernels

88%

Feng J. , Wu Z. , Qi D. , Jin Y. , Wu W.

International Agrophysics

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2019

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tom 33

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nr 3

7

Is food resource partitioning responsible for deviation of echolocation call frequencies from allometry in Rhinolophus macrotis?

88%

Shi L. , Feng J. , Liu Y. , Ye G. , Zhu X.

Acta Theriologica

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2009

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tom 54

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nr 4

371-382

EN

There is an apparent allometric relationship between peak frequency of echolocation and body size in rhinophilids. However, some rhinolophids deviate from this rule. To date this variation has been explained as a result of partitioning of communication channels. An alternative hypothesis that food resource partitioning results in this divergence in expected frequencies was tested by comparing prey selection between Rhinolophus macrotis Blyth, 1844 and Rhinolophus lepidus Blyth, 1844 in Yunnan Province, China. These two sympatric species are morphologically similar but acoustically divergent: R. macrotis has an echolocation frequency significantly lower than that predicted by the allometric relationship, whereas that of R. lepidus agreed with expectations. Prey selection experiments, conducted in a flight tent, indicated that the dominant prey taxa of R. macrotis were Lasiocampidae, Arctiidae and Noctuidae, whilst that of R. lepidus were Arctiidae, Noctuidae and Ichneumonidae. R. macrotis ate more earless moths and fewer eared moths than R. lepidus, and R. macrotis fed on larger prey in general and captured a wider size range than that captured by R. lepidus. These results confirmed the existence of finely tuned trophic niche differentiation and suggested that food resource partitioning is one of the factors leading to lower peak frequency of calls in R. macrotis.

8

Photosynthesis inhibition of pyrogallol against the bloom-forming cyanobacterium microcystis aeruginosa TY001

88%

Wang J. , Liu Q. , Feng J. , Lv J. , Xie S.

Polish Journal of Environmental Studies

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2016

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tom 25

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nr 6

EN

Severe eutrophication and harmful cyanobacterial blooms of freshwater ecosystems has been a persistent environmental topic in recent decades. Allelochemical inhibition has received great attention in aquatic ecology and quality management. This study investigates the growth and full photosynthesis performance of pyrogallol on Microcystis aeruginosa TY001. The growth and pigment contents of M. aeruginosa were seriously inhibited by pyrogallol. The relative expression levels of the nblA gene were up-regulated under pyrogallol treatments. Unexpectedly, the relative transcript abundance of the psaB and psbA genes significantly increased compared with the control, but the chlorophyll fluorescence parameters of M. aeruginosa TY001 decreased significantly, except at 1 mg L-1 pyrogallol. In conclusion, the target sites of pyrogallol’s toxic effect on the PSII of M. aeruginosa TY001 were mainly on the active reaction centers and the electron transport at the acceptor side.

9

Developmental gene expression of antimicrobial peptide Protegrin-1 and effect of weaning on gene regulation of Protegrin-1 in piglets

88%

Han F. F. , Wang Y. Z. , Feng J. , Guo J. , Xu Z. R.

Journal of Animal and Feed Sciences

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2007

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tom 16

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nr 1

86-95

10

Postnatal development of morphological features and vocalization in the pomona leaf-nosed bat Hipposideros pomona

88%

Jin L.-r. , Lin A.-q. , Sun K.-p. , Liu Y. , Feng J.

Acta Theriologica

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2011

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tom 56

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nr 1

EN

Based on mark-recapture data, we studied the postnatal development of morphological features and vocalization of the pomona leaf-nosed bat (Hipposideros pomona). Morphological changes indicated that body mass and length of forearm followed a linear pattern of growth until 13 days of age at mean growth rates of 0.14 g/day and 1.08 mm/day, respectively, and thereafter, growth rates slowed. The length of the total epiphyseal gap of the fourth metacarpal–phalangeal joint showed a linear increase for up to 10 days, followed by a linear decrease until day 40 at a mean rate of 0.09 mm/day. Together, two equations permitted estimation of the age of H. pomona pups between 1 and 40 days. The logistic equation provided the best fit to the empirical curves for body mass and length of forearm. Studies of vocal development showed that the precursors of echolocation calls were not emitted until day 7 after birth. As the pups grew, the dominant frequency (DF) of isolation calls increased and number of harmonics (NH) decreased, whereas the duration remained relatively stable. The DF and BFM2 (the bandwidth of the terminal frequency-modulated sweep from the second harmonic) of the early echolocation calls increased; however, the NH and duration decreased.

11

Numerical Study of the Effect of Furrows on Biosonar Beamforming in Aselliscus Stoliczkanus Bat

88%

He W. , Feng J. , Gao L. , Zhang Z. , Lu H.

Archives of Acoustics

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2017

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tom Vol. 42, No. 3

395--399

EN

The Aselliscus Stoliczkanus bat, studied here, has intricately shaped structures surrounding the nostrils. These structures are hypothesised to have influence on animals’ acoustic radiation patterns. Using micro-tomography scanning technique, a 3D digital model of the noseleaf is reconstructed and biosonar beam pattern is analysed using a finite element method based on the 3D noseleaf model. The present research focuses on the conspicuous furrows in noseleaf, and our analysis allows to conclude the followings: a) structural details in noseleaf of Aselliscus Stoliczkanus bat can produce acoustic effects even if it is not adjacent to the nostrils, b) the furrows possess frequency-selective characteristics, c) the furrows have the function to manipulate the direction and width of the outgoing ultrasound wave.

12

DC-Link Voltage Balancing Method with Reduced CommonMode Voltage for a Five-Level ANPC Inverter

88%

Wang K. , Li Y. , Zheng Z. , Xu L. , Feng J.

Przegląd Elektrotechniczny

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2013

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tom R. 89, nr 3b

32--34

EN

This paper presents a DC-link voltage balancing method with reduced common-mode voltage for a five-level active neutral-point clamped (ANPC) inverter. The DC-link voltage balancing method is based on zero-sequence voltage injection using carrier-based PWM. By further limiting the range of injected zero-sequence voltages, the amplitude of common-mode voltage can be reduced to 1/4 of the dc-link voltage. Experimental results are presented to verify the validity of this method.

PL

W artykule przedstawiono metodę balansowania napięciami kondensatorów obwodu pośredniczącego DC dla pięcio-poziomowego falownika Active NPC z redukcją napięcia common-mode. W metodzie wykorzystywana jest modulacja PWM z falą nośną i sygnałem kolejności zerowej, o regulowanym zakresie aplikacji. Przedstawiono wyniki eksperymentalne.

13

Function of distress calls in least horseshoe bats: a Field study using playback experiments

88%

Wu X. , Pang Y. , Luo B. , Wang M. , Feng J.

Acta Chiropterologica

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2018

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tom 20

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nr 2

EN

Many social animals utter distress calls in the context of fear. These vocalizations may serve to attract audiences for help, warn individuals of danger, and confuse the predator. Here, we aim to assess the function of distress calls in free-living least horseshoe bats, Rhinolophus pusillus. We recorded distress calls from four allopatric colonies in mainland China. Playback trials, consisting of distress calls, silence, and noise, were presented to bats outside three bat roosts. Rhinolophus pusillus emitted long, harsh, broadband calls when under duress. Playback of distress calls induced a significant increase in bat passes at the loudspeaker in comparison with control trials. The number of recorded echolocation pulses increased 3.2–6.1 folds during playbacks of distress calls compared to playbacks of silence, and 2.9–5.2 folds compared to playbacks of noise. There was a positive association between bat passes and echolocation vocalizations. However, some bats delayed their emergence from the roost in response to distress call stimuli. Despite similar delayed responses, more bat passes were detected in the presence of allopatric distress calls than those from colony members. Overall, the results indicate that distress calls could attract and warn conspecifics in least horseshoe bats.

14

Postnatal development in the big-footed bat, Myotis macrodactylus: wing morphology, echolocation calls, and flight

88%

Wang L. , Lin A. , Xiao Y. , Jiang T. , Feng J.

Acta Theriologica

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2014

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tom 59

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nr 3

EN

We studied the postnatal development of wing morphology and echolocation calls during flight in a free-ranging population of the big-footed bat, Myotis macrodactylus, using the mark-recapture methodology. Young bats were reluctant to move until 7 days of age and started fluttering at a mean age of 10 days. The wingspan and wing area of pups followed a linear pattern of growth until 22 days of age, by which time the young bats exhibited flapping flight, with mean growth rates of 0.62 mm/day and 3.15 mm2/day, for wingspan and area, respectively, after which growth rates decreased. Pups achieved sustained flight at 40 days of age. Of the three nonlinear growth models (logistic, Gompertz, and von Bertalanffy), the logistic equation provided the best fit to the empirical curves for wingspan and wing area. Neonates emitted long echolocation calls with multiple harmonics. The duration of calls decreased significantly between flutter (19 days) and flight (22 days) stages. The peak and start frequency of calls increased significantly over the 3-week period of development, but the terminal frequency did not change significantly over the development period.

15

Phytoremediation of phenol using Polygonum orientale and its antioxidative response

88%

Wang K. , Cai J. , Xie S. , Feng J. , Wang T.

Archives of Environmental Protection

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2015

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tom Vol. 41, no. 3

39--46

EN

Polygonum orientale with beautiful red flowers can be found as one dominant species in the vicinity of most water bodies and wetlands in China. However, its phytoremediation potential has not been sufficiently explored because little is known about its resistance to inorganic or organic pollutants. We investigated P. orientale response to low and moderate levels of phenol stress (≤ 80 mg L-1). Endpoints included phenol tolerance of P. orientale and the removal of the pollutant, antioxidant enzyme activities, damage to the cell membrane, osmotic regulators and photosynthetic pigments. In plant leaves, phenol stress significantly increased the activities of peroxidase (POD) and catalase (CAT), as well as the contents of proline, soluble sugars and carotenoids, whereas superoxide dismutase (SOD), H2O2 and electrolyte leakage (EL) levels remained unaltered. On the other hand, there were significant decreases of soluble protein and chlorophyll contents. We demonstrated that, in combination with phenol tolerance and its removal, P. orientale has efficient protection mechanisms against phenol-induced oxidative damage (≤ 80 mg L-1). We propose that P. orientale could be used as an alternative and interesting material in the phytoremediation of phenol.

16

Motion characteristics after ricochet: an experimental investigation

88%

Chen G. , Hu J. , Liu A. , Feng J. , Hu Q.

Polish Maritime Research

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2020

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tom 27

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nr 2

17

Postnatal growth and age estimation in the ashy leaf-nosed bat, Hipposideros cineraceus

88%

Jin L. , Lin A. , Sun K. , Liu Y. , Feng J.

Acta Chiropterologica

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2010

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tom 12

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nr 1

EN

We quantified changes in body mass, forearm length, and the total length of the epiphyseal gap of the fourth metacarpal-phalangeal joint of the ashy leaf-nosed bat (Hipposideros cineraceus) based on mark-recapture data obtained in Fangkong Cave in Hekou, Yunnan Province, China. We used these data to develop empirical growth curves, to derive growth rates, to establish age-predictive equations, and to compare growth parameters based on three nonlinear growth models. Forearm length and body mass of pups followed a linear pattern of growth until day 17, with mean growth rates of 0.81 mm/day and 0.09 g/day, respectively and thereafter their growth rates increased more slowly. The length of the epiphyseal gap initially increased linearly up to day 13 and then decreased linearly at a mean rate of 0.07 mm/day until day 37. An equation for estimating age based on forearm length was valid when this dimension was ≤ 27.6 mm, whereas the equation based on the length of the epiphyseal gap was valid for forearm lengths ≥ 24.3 mm. Together, these two equations permit estimation of the age H. cineraceus pups between 1 and 37 days. Of the three nonlinear growth models (logistic, Gompertz, and von Bertalanffy), the logistic equation provided the best fit to the empirical curves for body mass and forearm length.

18

Coexistence of Rhinolophus affinis and Rhinolophus pearsoni revisited

88%

Jiang T. , Lu G. , Sun K. , Luo J. , Feng J.

Acta Theriologica

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2013

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tom 58

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nr 1

EN

The investigation of mechanism of species coexistence promotes understanding of the mechanistic processes behind community ecology and ecosystem functions. Niche theory declares that species coexistence within a community must partition the resources of their environment. Two sympatric and morphologically similar bat species, Rhinolophus affinis and Rhinolophus pearsoni, provided a unique opportunity to test the causal mechanism of coexistence. Previous study showed that their coexistence was promoted not by the trophic and spatial niche differentiation but the relatively high abundance of prey resources, which was not in accord with the prediction of niche theory. Here, therefore, we reanalyzed the dietary composition by fecal analysis and surveyed the feeding time of both species. Our results showed that R. affinis and R. pearsoni hunt mainly mostly on Coleoptera and Lepidoptera, and there was a very high overlap (0.84) of trophic niche between the two species. However, significant difference in the duration of the activity period between both species was detected, which illustrated that temporal partitioning of prey resource use facilitated their coexistence. Additionally, our work highlighted the importance of integration of the traditional methods and next-generation sequencing methods for identifying dietary composition of carnivores, and suggested that ongoing studies of species coexistence must consider simultaneously multiple niche axes.

19

Effect of dietary bovine lactoferrin on lipid peroxidation and activities, and mRNA levels of antioxidant enzymes of piglets

88%

Xu C. L. , Wang Y. Z. , Liu J. X. , Yao G. J. , Feng J.

Journal of Animal and Feed Sciences

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2006

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tom 15

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nr 4

609-620

EN

The experiment was conducted to evaluate effect of dietary bovine lactoferrin (bLF) on lipid peroxidation and activities as well as mRNA levels of antioxidant enzymes of piglets. Duroc×Landrace×Yorkshire crossbred female piglets (n=120, 35 days of age, liveweight 9.70±0.71 kg) were fed a diet containing 0, 1250, or 2500 mg/kg bLF for 30 days. After completion of the feeding experiment, twelve female piglets with 4 animals in each treatment were randomly selected to determine malondialdehyde (MDA) and total antioxidant capacity (TAOC) levelsczinc- superoxide dismutase (CuZnSOD), glutathione perioxidase (GPx), catalase (CAT) activities in serum and liver, and CuZnSOD, GPx and CAT mRNA levels in liver. Results showed that piglets treated with 2500 mg/kg bLF significantly increased (P<0.05) TAOC levels, the activities of GPx, CuZnSOD and CAT, and mRNA levels of CuZnSOD, GPx and CAT, and decreased (P<0.05) the contents of MDA as compared with control. Supplementation with 1250 mg/kg bLF also increased (P<0.05) the activities of CuZnSOD, GPx and CAT and mRNA levels of GPx and CAT, and decreased (P<0.05) the contents of MDA as compared with control, but the effect was not better than that of dietary addition of 2500 mg/kg bLF (P<0.05). The study indicated that addition of bLF improved the antioxidant function of piglets by up-regulation of mRNA levels and activities of certain antioxidant enzymes associated with free radicals metabolism.

20

The construction of the eukaryotic expression plasmid pcDNA3.1-azurin and the increased apoptosis of U2OS cells transfected with it

88%

Ye Z. , Peng H. , Fang Y. , Feng J. , Yang D. S.

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nr 3

EN

In our previous study, we demonstrated that azurin could selectively trigger apoptosis in human osteosarcoma cell line U2OS cells. However, the rate of apoptosis (35.8 ± 3.2%) is not very high, and azurin is too expensive to obtain readily. To solve these problems, we constructed a eukaryotic expression plasmid containing the azurin gene with an influenza virus haemagglutinin 9 peptide HA epitope tag, and transfected the recombinant plasmid pcDNA3.1(+)/azurin into U2OS cells. RT-PCR and Western blot analysis validated the successful transfection and the expression of the azurin-HA protein. Conspicuous apoptosis of the transfected cells was detected by flow cytometry (FCM) and the DNA ladder test. The apoptosis rate reached 64.3 ± 13.1%. The transcriptional levels of the Bax and p53 genes increased significantly in U2OS cells transfected with pcDNA3.1(+)/azurin, but the Bcl-2 mRNA level decreased. There was no difference in the levels of Bcl-xl mRNA and Survivin mRNA. We propose that the transfection of the recombinant plasmid pcDNA3.1(+)/azurin can significantly induce apoptosis in U2OS cells. This is closely associated with the up-regulation of the transcriptional level of the Bax and p53 genes, and the down-regulation of that of the Bcl-2 gene.