Wyniki wyszukiwania - BazTech

1

Ground-Active Arthropod Recovery in Response to Size of Shrub Plantations in a Desertified Grassland Ecosystem

Liu R., Liu J., Zhao J., Xi W., Yang Z.

Polish Journal of Ecology

|

2017

|

Vol. 65, nr 3

410--422

EN

The ground-active arthropod diversity response to size of shrub plantations in desertified grassland ecosystems is largely unknown. In the study ground-active arthropods were collected by pitfall trapping beneath shrub canopy of very low, low, medium and high size, with adjacent mobile sandy land as a control. It was found that arthropod dominant taxa from mobile sandy land were significantly distinctive from those from plantations of different shrub size. A considerably lower Sørensen index (i.e., 0.25-0.48) was found between the arthropod communities from mobile sandy land and the canopy of either shrub size, than between those under low and medium/high shrub size (i.e., 0.62 to 0.69). The arthropod total abundance was significantly greater under the shrub canopy of very low size in comparison to that of low and medium shrub size and mobile sandy land, with the intermediate values under shrub canopy of high shrub size. Taxon richness and diversity of arthropod communities were distinctly lower under the shrub canopy of low size in comparison to very low, medium and high shrub size. The shrub size was found to have different effects on the density and richness distribution of arthropod trophic groups (i.e., predators, phytophagous, saprophagous, and omnivorous). It was concluded that shrub plantations could facilitate ground-active arthropod diversity recovery when they were afforested in mobile sandy land. There was a contrasting effect of shrub size on ground-active arthropod diversity recovery versus arthropod abundance when grazing was excluded.

2

Adsorption kinetics of fluoride on bone char and its regeneration

Hu J., Wu D., Rao R., Liu R., Lai W.

Environment Protection Engineering

|

2017

|

Vol. 43, nr 3

93--112

EN

The adsorbent of bone char (BC), produced from the pyrolysis of crushed animal bones, was dominated by the mesopores of the Brunauer Emmett Teller (BET) surface area. The optimal condition for defluoridation with BC was a pH level near 5.0. Chloride and nitrate ions could increase fluoride adsorption capacity in contrast with the effect of sulfate and carbonate ions. The interchangeability between fluoride and hydroxyl groups on BC sorbent was proved by the Fourier transform infrared spectroscopy. Langmuir equation had a better correlation coefficient than the Freundlich equation at various temperatures. Thermodynamic parameters such as Delta G degrees, Delta H degrees, Delta S degrees, Ea and S*, have been calculated to describe the nature of fluoride adsorption onto BC. Negative Delta G degrees and Delta H degrees values at various temperatures indicate a spontaneous process, and its exothermic effect, respectively. However, a positive Delta S degrees value represents an increasing process for entropy. The E-a and S* values ranging from 5 to 40 kj.mol-1 and 0 to 1, respectively, demonstrated that the adsorption is dominated by physical process, although the adsorption kinetic process was involved external diffusion, intraparticle diffusion and chemical reaction equilibrium stage. A high concentration of NaOH solution increases efficiency of removing adsorbed F- ions from the BC surface.

3

The Effect of the Energetic Additive Coated MgH2 on the Power of Emulsion Explosives Sensitized by Glass Microballoons

Cheng Y., Wang Q., Liu F., Ma H., Shen Z., Guo Z., Liu R.

Central European Journal of Energetic Materials

|

2016

|

Vol. 13, no. 3

705--713

EN

Traditional emulsion explosives, in spite of excellent water resistance, safe handling and good storage performance, have low power problems which seriously hinders their use. In order to improve the power of emulsion explosives, a hydrogen based emulsion explosive was devised. Scanning electron microscope pictures and experimental storage results show that the coating effect and stability of coated magnesium hydride (MgH2) are very good. The power of an emulsion explosive sensitized by glass microballoons was significantly increased (24.30 mm compression of lead block) after adding coated MgH2, compared to only 16.10 mm compression when not added. Thus emulsion explosives with coated MgH2 as an energetic additive have many potential applications.

4

Deblending of Simultaneous-source Seismic Data using Fast Iterative Shrinkage-thresholding Algorithm with Firm-thresholding

Qu S., Zhou H., Liu R., Chen Y., Zu S., Yu S., Yuan J., Yang Y.

Acta Geophysica

|

2016

|

Vol. 64, no. 4

1064--1092

EN

In this paper, an improved algorithm is proposed to separate blended seismic data. We formulate the deblending problem as a regularization problem in both common receiver domain and frequency domain. It is suitable for different kinds of coding methods such as random time delay discussed in this paper. Two basic approximation frames, which are iterative shrinkage-thresholding algorithm (ISTA) and fast iterative shrinkage-thresholding algorithm (FISTA), are compared. We also derive the Lipschitz constant used in approximation frames. In order to achieve a faster convergence and higher accuracy, we propose to use firm-thresholding function as the thresholding function in ISTA and FISTA. Two synthetic blended examples demonstrate that the performances of four kinds of algorithms (ISTA with soft- and firm-thresholding, FISTA with soft- and firm-thresholding) are all effective, and furthermore FISTA with a firm-thresholding operator exhibits the most robust behavior. Finally, we show one numerically blended field data example processed by FISTA with firm-thresholding function.

5

Effect of Shrub Microhabitats on Aboveground and Belowground Arthropod Distribution in a Desertified Steppe Ecosystem

Liu R., Zhu F., Steinberger Y.

Polish Journal of Ecology

|

2015

|

Vol. 63, nr 4

534--548

EN

The influence of the shrub canopy on the spatial distribution of above and below ground arthropod communities in desertified ecosystems is largely unknown. Using the shrubs Hedysarum scoparium (H. scoparium) and Artemisia ordosica (A. ordosica) as model systems, the above and belowground arthropod communities were sampled by using pitfall trapping and hand-sorting, in order to examine the linkage between above and belowground arthropods across shrub microhabitats. Different profile layers harboured mostly distinct arthropod taxon and trophic groups that preferred specific microhabitats. Even the common taxa, including the Carabidae and Formicidae families, were found to have different abundance distributions in above and belowground soil layers across shrub microhabitats. Total abundance distribution was found to differ, while taxon-richness and Shannon-index distributions were similar in above and belowground parts across the shrub microhabitats. Markedly higher taxon-richness and Shannon-index values were found beneath the shrub canopy compared to the open spaces, particularly beneath the A. ordosica shrub canopy. The abundance distribution in above and below ground arthropod communities were affected by the shrub microhabitats along vertical and horizontal axes more than the richness and diversity of these communities. The A. ordosica shrub canopy (compared with the H. scoparium shrub) was found to have greater ecological implications on the spatial distribution of the arthropod communities. All these findings were expected to be helpful for the conservation of biodiversity, shrub plantation management, and desertification control.

6

Enhancing the Thermal Protective Performance of Firefighters' Protective Fabrics by Incorporating Phase Change Materials

Zhu F L, Feng Q Q, Liu R, Yu B, Zhou Y

Fibres & Textiles in Eastern Europe

|

2015

|

Vol. 23, no. 2 (110)

68--73

EN

A composite fabric consisting of an outer shell, moisture barrier, thermal liner and comfort layer used for firefighters’ protective clothing, was incorporated with shape-stabilised phase change material (PCM) powder in order to improve the thermal protection capability provided by thermal protective clothing. Then we conducted a series of FTP (fire testing protection) experiments to investigate the effects of PCM location and phase change temperature on the heat protection efficiency of firefighters’ protective fabrics (FFPFs). Simultaneously the thermoregulation performance of the composite fabrics with PCMs was evaluated by using step-cooling experimental technology during the cooling process. Data from the FTP tests were also compared with those from the existing enthalpy formulation model of heat transfer through FFPFs embedded with PCMs. It was concluded that the use of PCMs could improve the heat buffering capacity. However, as PCM has a moderate melting temperature, it is better than the other two samples because they have a lower and higher melting temperature. Therefore PX 52 PCMs (melting temperature: 47 - 53 °C) could provided the maximum heat protection time compared with the other two kinds of PCMs.

PL

W celu zwiększenia zdolności ochrony termicznej odzieży ochronnej dla strażaków, przy użyciu stabilizowanego materiału zmiennofazowego w postaci proszku, stworzono materiał kompozytowy składający się z powłoki zewnętrznej, warstwy stanowiącej barierę dla wilgoci, wkładki termicznej i warstwy zapewniającej komfort. W celu zbadania wpływu umieszczenia materiału zmiennofazowego i temperatury przemiany fazowej na efektywność ochrony cieplnej przeprowadzono serię eksperymentów (testy ochrony przeciwpożarowej). Jednocześnie oceniono zdolność termoregulacji tkanin kompozytowych, oceny tej dokonano stosując technikę stopniowego chłodzenia. Dane z badań porównano z danymi teoretycznymi. Stwierdzono, że stosowanie materiałów zmiennofazowych może poprawić zdolność buforowania ciepła. Określono optymalny rodzaj materiału zmiennofazowego.

7

Synthesis, Crystal Structure, and Properties of a Novel, Highly Sensitive Energetic, Coordination Compound: Iron (II) Carbohydrazide Perchlorate

Liu R., Zhou Z., Qi S., Yang L., Wu B., Huang H., Zhang T.

Central European Journal of Energetic Materials

|

2013

|

Vol. 10, no. 1

17--36

EN

A single crystal of iron (II) carbohydrazide perchlorate [FeII (CHZ)3](ClO4)2 (FeCP), a novel, lead-free, energetic coordination compound, was synthesized and its structure determined by X-ray single crystal diffraction for the frst time. The crystal belongs to the monoclinic system P2(1)/n space group, with a = 1.0066(2) nm, b = 0.8458(2) nm, c = 2.1194(4) nm, β = 100.693(3)° and Z = 4. The central Fe(II) ion is coordinated to three bidentate carbohydrazide units through the carbonyl oxygen atom and an amino nitrogen atom, forming a six-coordinated, non-centrosymmetric complex cation. The thermal analyses by differential scanning calorimetry and thermogravimetry show that the onset temperature of thermal decomposition (152.7 °C) and the critical temperature of thermal explosion of FeCP (161.2 °C) are both much lower than those of other transition metal carbohydrazide perchlorate compounds, and also those of some other primary explosives in service. FeCP has a high enthalpy of combustion, as measured by oxygen bomb calorimetry. The impact, friction and fame sensitivity tests indicate that FeCP is extremely sensitive and hazardous. Unexpected explosions occurred even during the operational processes. In order to explore the intrinsic cause of these explosions, theoretical calculations of the orbital energies were performed based on DTF. These results reveal that the impact sensitivity is positively correlated with the energy gap between HOMO and LUMO: the smaller energy gap results in the higher impact sensitivity.

8

Applied Research of Route Similarity Analysis Based on Association Rules

Xiang Z., Liu R., Hu Q., Shi C.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

|

2012

|

Vol. 6, no. 2

181--185

EN

In recent years, with the development of information technology, businesses have accumulated a lot of useful historical data, as the shipping industry does. These data can be found deposited a large number of "knowledge", for example, Shipping records for historical information, Ship-Port relations information, Ship-ship relations information, Port & shipping route relations, Shipping route information. It can provide intellectual support to shipping informatization development. Association rules in data mining technology is one of important technologies. The technology, based on sta-tistical methods, can mine the associated and implied "knowledge" from data warehouse ,which has a large number of accumulated data. Apart from this, the technology can also play an important role in the prediction. In this paper, based on FP-growth algorithm, we improve it forming Relevent ships routes. From the prevalent perspective of data mining, deal with the corresponding vessels' dynamic information, ac-quired from the AIS, such as data collection, data statistics. On this basis, get the ship-port relation and ship-ship relation after a certain level of data analysis, processing, handing. Furthermore, this paper use the numer-ous historical ship-port relation and ship-ship relation to build a mathematical model on the ship-port and ship-ship relation. And use the improved association algorithm, FP-growth algorithm, to acquire the strong association rules between ship-port and ship-ship, and eventually mine the similarity of the ship route. Main points of this paper as follows: Collect ,count and check the data, which is from ship dynamic information; Establish the mathematical model between ship-port and ship-ship relation; Improve the algorithm; Analyse the similarity of ship route more accurately using the improved algorithm.

9

Detection of PD under Oscillatory Impulse Voltage

Liu R., Li J., Fan Y., Tian W.

Przegląd Elektrotechniczny

|

2012

|

R. 88, nr 7a

117-121

EN

In order to study the partial discharge (PD) pulses under oscillatory impulse voltage (OIV), an oscillation waveform generator is designed and the waveform parameters expressions are presented based on the equivalent circuit model. A high-frequency current transducer is developed for measurement of PD. Then the effects of coil turns and integral resistance on frequency properties are studied. Moreover, calibration and analysis of the actual dynamic response are performed by adopting function generator and square-wave source. The PD measurement system to detect the PD signals of needle-plate model under OIV is provided finally. Experiment shows that by adapting this PD measurement system, the source interferences are restrained and PD signals are effectively extracted, therefore it could be a worthy approach not only for further study on PD character under OIV, but also to explore the mechanism behind it.

PL

Zaprojektowano generator napięć impulsowych przeznaczony do badań wyładowań niezupełnych pod wpływem napięć impulsowych. Zaprojektowano też wysokoczęstotliwościowy czujnik prądu. Wyładowania niezupełne badano w układzie miedzy ostrzem a płaszczyzną. Uzyskano eliminację sygnału interferencji i dobrą ekstrakcję sygnału wyładowania.

10

Influence of grazing exclusion on soil macro-invertebrate diversity in degraded sandy grassland (Inner Mongolia, China)

Liu R., Zhao H., Zhao X.

Polish Journal of Ecology

|

2012

|

Vol. 60, nr 2

375-385

EN

In arid and semi-arid areas, heavy grazing combined with climate change cause land degradation (e.g., desertification). Grazing management is essential for ecosystem recovery and desertification control in these areas, including Northern China.s Horqin Sandy Land. However, the recovery of soil faunal community during grazing exclusion is unknown. We examined plant and soil macro-invertebrate community structure together with soil properties in three treatments in a representative degraded Horqin sandy grassland: exclosure for 15 and 10 years (15EX and 10EX) and long-term continuous grazing (CG). The vegetation cover and height increased significantly and soil bulk density decreased significantly along the gradient from CG to 15EX, but there were no significant differences in soil pH, electrical conductivity, organic carbon and total nitrogen. Soil macro-invertebrate abundance, group richness and diversity increased along the gradient from CG to 15EX, with significant differences in invertebrate abundance and group richness between CG and 15EX; there was no significant differences between CG and 10EX. There were no significant differences in soil macro-invertebrate diversity and evenness between these three treatments. These results suggested that grazing exclusion for at least 15 years might be necessary for the recovery of these fauna. The vegetation height and the soil electrical conductivity, organic carbon, and total nitrogen determined the distribution and community structure of soil macro-invertebrates. Some faunal groups lived in specific habitats due to strong adaptation to different management practices. For example, the Thomisidae, Philodromidae, Salticidae, and Rhopalidae tended to live in habitats with tall vegetation. The Lygaeidae, Miridae, Teneberionidae, and Linyphiidae adapted to live in soil with low soil organic carbon and nitrogen (ungrazed grassland).

11

Leaf nitrogen resorption pattern along habitats of semi-arid sandy land with different nitrogen status

Luo Y., Zhao X., Zuo X., Zhang J., Liu R., Wang S.

Polish Journal of Ecology

|

2010

|

Vol. 58, nr 4

707-716

EN

To assess nitrogen (N) resorption patterns in semi-arid sandy land, N concentrations in green leaves (N[g]) and senesced leaves (N[s]) of 35 species of shrubs and herbages were measured along habitats of decreasing soil total N (0.54 to 0.041 g g[^-1] d.w. of top soil level) in Horqin Sandy Land (Inner Mongolia, China). These habitats are following: inter-dune grassland (IDG), fixed sand dune (FD), semi-fixed sand dune (SFD), semi-mobile sand dune (SMD), and mobile sand dune (MD) were considered. Results showed that Ng and Ns (i.e. nitrogen resorption proficiency, NRP) increased and leaf nitrogen use efficiency (NUE) decreased significantly with increasing soil N status across the above habitas, but nitrogen resorption efficiency (NRE) was not affected. The levels of N[g], N[s] and NUE experience two stages across habitats: first, there were low N[g] and N[s and high NUE in MD and SMD; second, there were high N[g] and N[s] and low NUE in IDG, FD and SFD. Plants from IDG, FD and SFD had incomplete N resorption during foliar senescence, but plants from MD and SMD had complete N resorption. Leaf NRE was determined by life forms which had no significant effect on N[g] but on N[s] and NUE. For all plants in the five habitats, NRE and NUE decreased with the sequence of grass, herb, shrub, while Ns showed a contrary tendency. Plants from strong N limitation habitats did not show higher NRE, but showed higher NRP and leaf NUE, so NRP was a more sensitive indicator of changes in N status than NRE. In conclusion, Leaf N resorption patterns were mainly determined by soil N status across habitats, and there were some consistent patterns among life forms.

12

Fabric mechanical-surface properties of compression hosiery and their effects on skin pressure magnitudes when worn

Liu R., Kwok Y.-L., Li Y., Lao T. T.

Fibres & Textiles in Eastern Europe

|

2010

|

Vol. 18, no. 2 (79)

91--97

EN

Compression hosiery (CH) is one kind of mechanical therapeutic approach for the prophylaxis and treatment of venous disorders in the lower limbs. Their compression functional performance and comfort sensations are largely related to their material properties. The objective of this study was to comprehensively investigate the mechanical and surface properties of CH fabrics and their effects on corresponding skin pressure magnitudes in practical application. The mechanical testing of the material and skin pressure objective measurements applied to different kinds of CHs with four pressure levels were carried out using the Kawabata Standard Evaluation System and Multichannel skin pressure measuring system. This study shows that significant differences in material properties existed in CH fabrics with different pressure levels. Tensile energy (WT), tensile strain (EM), shearing stiffness (G) and bending rigidity (B) are key mechanical material indices, significantly correlative to skin pressure magnitudes; CHs fabrics with higher levels of pressure were rougher, stiffer and had less extensibility, but they had better dimensional stability. Significant differences in tensile, compression and surface properties existed between CHs fabrics in series A and those in B. The hosieries in series A produced more linear correlations between the key material indices and skin pressure magnitudes, which can be attributed to their fabrics having a smoother surface, greater elasticity, resilience and better dimensional stability. Moreover, proper surface properties of the material and hose design may enhance the pressure functional performance of compression hosiery products.

PL

Pończochy uciskowe są jednym z rodzajów mechanicznej terapeutyki stosowanej w profilaktyce i leczeniu chorób żylnych kończyn dolnych. Działanie ich zależy w dużej mierze od zastosowanego materiału. Celem badania było określenie właściwości mechanicznych i powierzchniowych pończoch i wpływu wywieranego ciśnienia w praktyce. Badania wykonano dla czterech poziomów ciśnienia przy użyciu systemu Kawabata i wielokanałowego układu mierzenia ciśnienia. Wykazano, że występują istotne różnice przy stosowaniu rożnych materiałów przy różnych poziomach ciśnienia. Ważnymi czynnikami wpływającymi na wielkości ucisku skóry są energia i odkształcenie przy naprężaniu oraz sztywność ścinania i zginania. Stwierdzono, że pończochy uciskowe o wyższym poziomie wywieranego ciśnienia były mniej delikatne, sztywne i wykazywały mniejszą rozciągliwość ale miały lepszą stabilność wymiaru. Przebadano różne serię wyrobów pończoszniczych i określone różnice pomiędzy nimi.

13

High pressures studies on hydrides of selected manganese alloys

Sugiura H., Filipek S., Paul-Boncour V., Marchuk I., Liu R., Pyun S.

Nukleonika

|

2006

|

Vol. 51,suppl.1

73-77

EN

Specific behavior found in hydrides formed in manganese, Mn-Ni and YMn2 under high pressure is presented and discussed. The synthesis of ferromagnetic fcc-manganese was proved. Parameters of the equations of state (EOS) derived from measurements in the diamond anvil cell (DAC) are summarized for manganese hydrides and for hydrides derived from YMn2 Laves phase. It was found that the compression behavior of recently discovered YMn2H6 is different from YMn2-based hydrides with lower hydrogen content.

14

Computer modelling of the Lyocell fibre spinning process

Shao H., Liu R., Hu X.

Autex Research Journal

|

2003

|

Vol. 3, no. 1

16--22

EN

The cellulose Lyocell fibre spinning process can be divided into two processes, a dry spinning process in the air gap, and a wet spinning process in the coagulation bath. In order to simulate the process in the air gap, the heat capacity Cp, the density ρ, and the elongational viscosity ɳ were measured by experiments carried out as a function of temperature and concentration of cellulose. The calculated diameters and temperature profiles along the spinning path were compared with the experimental results. The concentration of N-methyl-morpholine-N-oxide (NMMO) in the fibre (in the coagulation bath) was also measured during the experiments, and the diffusion coefficient was then calculated. Using the data obtained, the time during which the NMMO content in the fibre reaches the equilibrium state in the coagulation bath can be predicted.