Wyniki wyszukiwania - Biblioteka Nauki

1

An advanced machining simulation environment employing workpiece structural analysis

100%

Ratchev S. , Liu S. , Huang W. , Becker A. A.

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2006

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tom Vol. 16, nr 1-2

139--144

EN

Purpose: The study aims to reduce the surface dimensional error due to the part deflection during the machining of thin wall structures, thus, reduce machining costs and lead times by producing “right first time” components. Design/methodology/approach: The proposed simulation environment involves a data model, an analytical force prediction model, a material removal model and an FE analysis commercial software package. It focuses on the development of the simulation environment with a multi-level machining error compensation approach. Findings: The developed simulation environment can predict and reduce the form error, which is a limitation of the existing approaches. Research limitations/implications: The energy consumption, temperature change and residual stress are not studied in this research. Practical implications: The developed method provides a platform to deliver new functionality for machining process simulation. The convergence of the proposed integrated system can be achieved quickly after only a few iterations, which makes the methodology reliable and efficient. Originality/value: The study offers an opportunity to satisfy tight tolerances, eliminate hand-finishing processes and assure part-to-part accuracy at the right first time, which is a limitation of previous approaches.

2

Ethnobotanical study on medicinal plants used by Li people in Ledong, Hainan Island, China

89%

Huang W. , Li P. , Liu Y. , Huang W. , Ju Y. , Wang J. , Ntumwel C. B. , Long C.

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nr 1

EN

The paper documents on the uses of traditional medicinal plants used for treating human ailments in three villages of Ledong, a county inhabited by Liethnic group in the southwest of Hainan Province, China. Semi-structured interviews, key informant interviews and participatory observations were used to collect ethnobotanical data from February to March 2012 and in July 2013. The data collected was analyzed using descriptive statistics. Thirty native knowledgeable people were interviewed. The Li community uses 50 plant species in 36 families for medicinal purposes. The most common medicinal plant families were Leguminosae (14%), Compositae (6%), and Euphorbiaceae (6%), and the most common preparations methods were decoction (84%), crushing (38%), and poultice (34%). The traditional medicinal plants were mainly used for hemostasis (12.9%), body pains (11.4%), gastrointestinal disorders (11.4%), and trauma (10%). Twenty-four species of medicinal plants (48%) have never been reported in the literature of Li medicines. In addition, 22 species (44%) have already been studied by researchers and their extracts or compounds were good bioactives. However, the rapid socioeconomic development in the county is the main threat to the conservation of Li medicine and has resulted in the decrease in the abundance and use of medicinal plants and associated traditional knowledge. Other factors accounting for a decrease in the use of Li medicinal plants like loss of plant diversity, change of land use, and threatened traditional knowledge were equally discussed.

3

Trihelix family transcription factors in tea plant (Camellia sinensis): identification, classification, and expression profiles response to abiotic stress

88%

Li H. , Huang W. , Liu Z.-W. , Wu Z.-J. , Zhuang J.

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nr 10

4

Lithium Manganate Grown from Water-Solubility Explosive with EPS

75%

Xie X. , Wu H. , Wang W. , Wang M. , Huang W. , Li X.

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tom Vol. 3, nr 3

15-25

EN

Nanostructured spherical spinel lithium manganate with about 30 nm in diameter was synthesized for the first time by explosive method. The water-solubility explosive was prepared using a simple facility at room temperature. The growth of lithium manganate via detonation reaction was investigated with respect to the presence of an energetic precursor, such as the metallic nitrate and the degree of confinement of the explosive charge. The detonation products were characterized by scanning electron microscopy. Powder X-ray diffraction and transmission electron microscopy were used to characterize the products. Lithium manganate with spherical morphology and more uniform secondary particles, with smaller primary particles of diameters from 10 to 50 nm and a variety of morphologies were found. Lithium manganate with a fine spherical morphology different from that of the normal spinel is formed after detonation wave treatment due to the very high quenching rate. It might also provide a cheap large-scale synthesis method. Explosive detonation is strongly nonequilibrium processes, generating a short duration of high pressure and high temperature. Free metal atoms are first released with the decomposition of explosives, and then theses metal and oxygen atoms are rearranged, coagulated and finally crystallized into lithium manganate during the expansion of detonation process.

5

Carbon accumulation in the bulk soil and different soil fractions during the rehabilitation of desertified grassland in Horqin Sandy Land (Northern China)

75%

Li Y. , Zhao X. , Wang S. , Zhang F. , Lian J. , Huang W. , Mao W.

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tom Vol. 63, nr 1

88--101

EN

Desertification, which affects more than two-thirds of the world’s arid and semi-arid regions, is a significant global ecological and environmental problem. There is a strong link between desertification of the drylands and emission of CO2 from soil and vegetation to the atmosphere. The Horqin Sandy Land is a severely desertified area in China’s agro-pastoral ecotone due to its fragile ecology, combined with unsustainable land management. We estimated changes of organic carbon content in the bulk soil (0–5 cm), in the light-fraction of soil organic matter (based on density fractionation), and in the various particle-size fractions in areas with mobile sand dunes after implementing grazing exclusion (12 and 27 years) and tree and shrub planting (22 and 24 years). Carbon stocks in the bulk soil and all soil density and particle-size fractions increased significantly in the exclosure and plantation plots. The average rates of carbon accumulation in the bulk soil in the exclosure and plantation plots were 16.0 and 17.8 g m-2 y-1, respectively, versus corresponding values of 2.3 and 7.1 g m-2 y-1 for the light fraction, 4.3 and 8.0 g m-2 y-1 for the coarse fraction, 5.0 and 3.4 g m-2 y-1 for the fine sand, 4.5 and 4.2 g m-2 y-1 for the very fine sand, and 1.8 and 1.8 g m-2 y-1 for the silt+clay fraction. The older the exclosure and plantation, the more carbon accumulated in the bulk soil and in each fraction. The carbon pool exceeded the level in non-desertified grasslands after 27 years of grazing exclosure and 24 years of the shrub plantation. Our results suggest that both grazing exclusion and planting trees and shrubs can restore desertified grassland, creating a high potential for sequestering soil carbon, but that the plantations appeared to accumulate soil carbon faster than the exclosures.

6

Crystallization of TeO2-Nb2O5 glasses and their network structural evolution

75%

Lin J. , Huang W. , Ma L. , Bian Q. , Qin S. , Wei H. , Chen J.

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tom Vol. 27, No. 1

329--338

EN

TeO2-Nb2O5 glass is a kind of heavy metal oxide glass with a chain-like network structure, in which Nb5+ ions connect the Te-O chains and adjust the types of [TeOx] (x = 3, 4) coordination polyhedra to stabilize the glass network. (100 - y)TeO2-yNb2O5 (y = 3-20 mol %) glasses were prepared, the crystallization behaviour and their network structural evolution were studied by means of differential thermal analysis (DTA), X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR). The results show that the stabilization of the TeO2-Nb2O5 glass network is greatly influenced by the constitution of Te-O chains and their linkage. The glass structure with lower Nb5+ content is inhomogeneous, it is composed of edge sharing Te-O chains, partly edge sharing chains connected by Nb5+ ions, apical sharing chains and apical sharing chains connected by Nb5+ ions. Crystalline phases of ß-TeO2, Nb2Te4O13, .beta.-TeO2 and Te3Nb2O11 will be formed in turn when the treatment temperature of the glass is increased. When the concentration of Nb5+ ions is sufficient to well connect Te-O chains, the glass network will tend to homogenize, only one crystalline phase, Nb2Te4O13, will be formed. A suitable preheat treatment will also help to homogenize the glass structure and make the glass more stable.

7

Temperature dependence of Bi4Ge3O12 photoluminescence spectra

75%

Kaczmarek S. M. , Tsuboi T. , Nakai Y. , Berkowski M. , Huang W. , Kowalski Z.

Materials Science Poland

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2014

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tom Vol. 32, No. 1

7--11

EN

Bi4Ge3O12 single crystals were obtained using Czochralski growth method. Photoluminescence spectra were analyzed versus temperature from 12 to 295 K. Besides the previously observed emission bands at 610 and 820 nm, the new emission band at 475 nm was found by a careful temperature dependence measurement in the present study. The influence of basic and defect structure on the shape and position of the spectra versus temperature was discussed.

8

Application of ethanol and fatty acids induces Ca2plus responses in pancreatic stellate cells in vitro and leads to activation of these cells in vivo

75%

Ferdek P. E. , Jakubowska M. A. , Zhang X. , Huang W. , Sutton R. , Petersen O. H.

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nr S2

9

Coding single nucleotide polymorphisms and SmCPS1 and SmKSL1 subcellular localization are associated with tanshinone biosynthesis in Salvia miltiorrhiza Bunge roots

63%

Bai Z. , Liu J. , Zhang C. , Huang W. , Liang Z. , Yan X. , Liu Y. , Zhu Y.

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nr 01

EN

Tanshinone is one of the major medicinal components of the roots of Salvia miltiorrhiza Bunge, and SmCPS1 and SmKSL1 are key enzymes in the tanshinone biosynthesis pathway. To increase our understanding of the coding single nucleotide polymorphisms (cSNPs) involved in tanshinone biosynthesis, seven S. miltiorrhiza landraces were examined. Our results revealed that the tanshinone content was significantly different among the seven landraces. In total, 48 cSNPs in SmCPS1 and 47 cSNPs in SmKSL1 were identified, and of these, 38 and 42 cSNPs, respectively, were associated with tanshinone content. The highest A/G and C/T base substitution rates were in SmCPS1 and SmKSL1, respectively. SmKSL1 expression was significantly, positively correlated with tanshinone IIA and tanshinone I contents, and SmCPS1 expression was significantly associated with tanshinone IIA content. Interestingly, subcellular SmCPS1 and SmKSL1 expression was enriched in the plastids. Therefore, cSNPs of SmCPS1 and SmKSL1 are involved in tanshinone biosynthesis in the plastids, where SmCPS1 and SmKSL1 enzymes catalyze tanshinone production in this species.

10

Photosynthetic performance and growth traits in Pennisetum centrasiaticum exposed to drought and rewatering under different soil nutrient regimes

63%

Luo Y. , Zhao X. , Qu H. , Zuo X. , Wang S. , Huang W. , Luo Y. , Chen M.

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tom 36

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nr 02

EN

Responses of plants exposed to drought and rewatering have been well documented; however, little is known concerning strategies of psammophyte to drought and rewatering under different soil nutrient regimes. For this study, Pennisetum centrasiaticum under two soil nutrient regimes was subjected to progressive drought and subsequent rewatering. Soil water status, gas exchange characteristics, chlorophyll a fluorescence characteristics as well as biomass traits were measured to investigate ecophysiological responses. Net photosynthesis rate (Pn), stomatal conductance (gs), water use efficiency, maximum quantum efficiency of photosynthesis system II (PSII, FV/ FM), electron transport flux per cross section (ET₀/CS₀), and performance index on cross section basis (PICS) were suppressed during drought periods for both nutrient regimes. Meanwhile, leaf intercellular CO₂ concentration (Ci), minimal fluorescence intensity (F₀), and dissipated energy flux per cross section (DI₀/CS₀) increased. Reversible downregulation of PSII photochemistry and enhanced thermal dissipation of excess excitation energy (DI₀/CS₀) contributed to enhanced photo-protection in drought-stressed plants. Thus, the results indicate that P. centrasiaticum is capable of withstanding and surviving extreme drought events, and the recovery pattern of stressed P. centrasiaticum under both nutrient regimes was similar. However, fertilization increased the biomass and the variation in gas exchange and chlorophyll a fluorescence characteristics during drought periods. Additionally, fertilization accelerated the process of drought and aggravated stress under extreme drought events. Thus, the fertilization strategy used in P. centrasiaticum restoration should be carefully selected—fertilization may not always be beneficial.

11

Application and prospect of graphene and its composites in wastewater treatment

63%

Liu J. , Chen F. , Yao Q. , Sun Y. , Huang W. , Wang R. , Yang B. , Li W. , Tian J.

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2020

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tom 29

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nr 6

12

Decreased expression of the human carbonyl reductase 2 gene HCR2 in hepatocellular carcinoma

63%

Liu S. , Ma L. , Huang W. , Shai Y. , Ji X. , Ding L. , Liu Y. , Yu L. , Zhao S.

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nr 2

EN

Altered gene expression was associated with the induction and maintenance of hepatocellular carcinoma (HCC). To determine the significance of HCR2 in HCC, here we compare the expression levels of HCR2 in carcinoma and in paired non-carcinoma tissues using semiquantitative reverse-transcription polymerase chain reaction (RT-PCR), Western blot analysis, and immunohistochemical staining. The expression ratio (ER) of HCR2 between the tumor and paired tumor-free tissues was calculated for each case and the data was clinicopathologically analyzed. The expression of HCR2 mRNA was found to be significantly decreased in HCC tissues compared with paired normal tissues (P < 0.001). HCR2 was downregulated in 58% (n = 22) of 38 HCC patients. The ER of HCR2 was higher in Edmondson’s grade I/II carcinomas than that in Edmondson’s grade III/IV carcinomas (P < 0.05). Western blot analysis showed HCR2 to be notably depressed in carcinoma tissues in 3 out of 4 HCC patients. Immunohistochemical staining indicated most HCR2 protein accumulated in non-carcinoma cells. These results suggested that altered HCR2 expression might play roles in the carcinogenesis and progression of HCC, and it could be a clinical marker for prognosis, and a molecular target for screening potential anti-HCC drugs.