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Search Results: 1 - 10 of 126380 matches for " ZHANG Kao-Wen "
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Cotyledon loss and its effects on survival and growth of Quercus wutaishanica seedlings under different densities

YAN Xing-Fu,ZHOU Li-Biao,ZHANG Kao-Wen,ZHOU Yun-Feng,

植物生态学报 , 2012,
Abstract: Aims Our objective are to explore cotyledon predation by rodents and its effects on survival and growth of Quercus wutaishanica seedlings under different densities, and to disclose the potential bottlenecks limiting seedling recruitment and natural regeneration of populations. Methods We transplanted Q. wutaishanica seedlings at six densities of 3.24, 2.56, 1.96, 1.44, 1.00 and 0.64 individuals·m–2 in a Larix principis-rupprechtii plantation of China’s Dadaogou forest region, Liupan Mountains. We surveyed retention rate of seedling cotyledon (RRC), retention rates of taproot (RRT) and apical bud (RRA) after cotyledon predation by rodents and retention rates of cotyledon- and apical bud-predated (RRCP, RRAP) and cotyledon- and apical bud-remained seedlings (RRCR, RRAR). At the end of the experiments, we harvested all surviving seedlings and determined seedling height (SH), basal stem diameter (BSD), leaf number (LN), taproot length, leaf area per seedling (LAPS), total dry mass, root shoot ratio and specific leaf area. Important findings Density effect of cotyledon predation on Q. wutaishanica seedlings was observed and the RRC decreased with increase of seedling density. Six and five weeks after transplanting, the RRCs of two higher densities (3.24 and 2.56 individual·m–2) stabilized at their minimums (8.64% and 7.81%), while those of two lower densities (1.44 and 0.64 individual·m–2) were still higher at the last cotyledon survey and were signifycantly higher than those of all other density treatments (p < 0.05). The RRA was the highest (25.23%) in 1.44 individual· m–2 density and was higher (4.19%) than that in 3.24 individual·m–2 density (p < 0.05), and all other densities resulted in < 20% of RRA. Significant difference between RRCP and RRCR was detected only on certain survey dates of individual density. RRAP was slightly lower than RRAR, and individual density exhibited the inverse. The fluctuation of retention rate of different seedling types may have be resulted from new germinated sprouts after apical buds were gnawed. SH, BSD, LN and LAPS all increased slightly with density decrease. The maxima of all parameters except SH were detected under the density of 1.44 individual·m–2 and, to some extent, were related to whether cotyledon was predated by rodents or not, indicating that more seedlings grown at higher density lost their cotyledons and thus exerted influence on seedling growth.
Seedling regeneration of Quercus liaotungensis in Liupan Mountains, China

YAN Xing-Fu,DU Qian,SHI Chun,ZHOU Li-Biao,ZHANG Kao-Wen,

植物生态学报 , 2011,
Abstract: Aims Quercus liaotungensis forest, which occurs on shaded, semi-shaded and semi-sunny slopes at an elevation of 1 700–2 300 m, is the main natural secondary forest and zonal climax community in China’s Liupan Mountains. It is essential for forest management to better understand the natural regeneration processes and limiting factors in the restoration of degraded Q. liaotungensis shrubs and secondary Q. liaotungensis forest. Our objectives are to (a) investigate the important ecological processes associated with recruitment and seedling regeneration (seed production, seed bank composition, seed storage and seed/cotyledon predation) and (b) analyze potential bottlenecks limiting seedling regeneration. Methods We surveyed the seed production of Q. liaotungensis shrubs and soil seed bank composition of secondary Q. liaotungensis forest in Daliang Mountain and Qiuqianjia forest region of Liupan Mountains, respectively. We also investigated the effects of moist sand and natural air-dry storage on seed life-span and the effects of cotyledon predation (by excluding animals) on seedling establishment. Important findings The percentage of viable seeds of Q. liaotungensis shrubs was 27.51%, and the rate of seed predation/removal (41.51%) was significantly higher than that of other seed types (P < 0.01). The rate of germination and insect infection in soil seed bank of secondary Q. liaotungensis forest was 35.16% and 38.29%, respectively, while only 13.65% of seeds were viable in the soil seed bank. Seed predators played an important role in influencing the density of the soil seed bank by removing and hoarding seeds. Storage in moist sand for 60 d resulted in germination of 96.67% of Q. liaotungensis seeds, and both short-term moist sand and air-dry storage led to accelerated germination timing and enhanced germination percentage and germination index. However, with the extension of the storage period, germination was delayed and germination percentage, germination index and vigor index were decreased. Survival rates of seedlings treated by predator elimination caged seedlings were 80% and 83% in forest gap and under canopy, respectively, while only 25% and 31% of survival rate, respectively, were found for uncaged seedlings, indicating the important role of cotyledons in seedling establishment. The predation rate of cotyledons in forest gaps (85.00%) was higher than that under canopy (71.00%). Although the survival rate of seedlings with cotyledons in forest gaps (6.00%) was higher than that under canopy (15.50%), the survival rate of cotyledon-predated seedlings in forest gaps (18.50%) was similar to that under canopy (18.00%).
Electronic structures and magnetic properties in SmCo7-xMx

Wang Pei-Ji,Kao Hong,Zhang Chang-Wen,Yu Feng,Zhou Zhong-Xiang,

中国物理 B , 2009,
The Pion Electroproduction in the $Δ$(1232) region region
Chung Wen Kao
Physics , 1999,
Abstract: The amplitudes of the pion electroproduction from the nucleon are derived up to third order in the chiral effective theory including explicit $\Delta$(1232) >. The Q^2 evolutions of weighted integrals of amplitudes are presented.
Distribution of Nuclei of Different Ploidy Levels during Ovule, Seed and Protocorm Development in Phalaenopsis aphrodite subsp. formosana (Orchidaceae)  [PDF]
Goamg-Tyng Jean, Yu-Lin Kao, Ching-Yan Tang, Wen-Huei Chen
American Journal of Plant Sciences (AJPS) , 2011, DOI: 10.4236/ajps.2011.23037
Abstract: Distribution of nuclei of different ploidy levels was studied at different developmental stages in the embryonic tissue of the ovule, seed and protocorm of Phalaenopsis aphrodite subsp. formosana (Miwa) E.A. Christ. by a combination of flow cytometry and fluorescence microscopy with Apo Tome Slider. Three stages of ploidy patterns were identified in the ovular tissue at different days after pollination (DAP). Firstly, between pollination and fertilization (0 to 50 DAP), 2C nuclei were dominant over 4C nuclei and resulted in low level of cycle value. Secondly, between fertilization and seed maturation (50 to 110 DAP), amount of 4C nuclei increased rapidly, maintained at a high level and then decreased gradually to a low level. Small amount of 8C nuclei was also detected at this stage. Thirdly, at seed maturation (110 to 130 DAP), 2C nuclei became dominant over 4C nuclei again and the cycle value remained at a low but significant level at this stage. After seed sowing, nuclei with ploidy levels of 2C, 4C and 8C were observed in the developing protocorms as early as at 4 DAS (days after sowing). Nuclei with high ploidy levels (8C and 16C) increased gradually until 40 DAS in this study. Significant level of cycle value at this stage of protocorm development indicated the presence of endopolyploidy. 4,6-diamido-2-phenylindol (DAPI) staining showed large and prominent nuclei in the basal portions of the mature seeds before sowing and in the developing protocorms at 20 DAS. These findings clearly demonstrate the occurrence of different distribution patterns of nuclei with different ploidy levels during ovule, seed and protocorm de-velopment in Phalaenopsis aphrodite. These observations will provide fundamental information for further studies in Phalaenopsis orchids.
QCD Chiral restoration at finite $T$ under the Magnetic field: Studies based on the instanton vacuum model
Chung Wen Kao,Seung-il Nam
Physics , 2011, DOI: 10.1007/s00601-012-0352-z
Abstract: We investigate the chiral restoration at finite temperature $(T)$ under the strong external magnetic field $\vec{B}=B_{0}\hat{z}$ of the SU(2) light-flavor QCD matter. We employ the instanton-liquid QCD vacuum configuration accompanied with the linear Schwinger method for inducing the magnetic field. The Harrington-Shepard caloron solution is used to modify the instanton parameters, i.e. the average instanton size $(\bar{\rho})$ and inter-instanton distance $(\bar{R})$, as functions of $T$. In addition, we include the meson-loop corrections (MLC) as the large-$N_{c}$ corrections because they are critical for reproducing the universal chiral restoration pattern. We present the numerical results for the constituent-quark mass as well as chiral condensate which signal the spontaneous breakdown of chiral-symmetry (SB$\chi$S), as functions of $T$ and $B$. Besides we find that the changes for the $F_\pi$ and $m_\pi$ due to the magnetic field is relatively small, in comparison to those caused by the finite $T$ effect.
The third Zemach moment and the size of the proton
Bea Ya Wu,Chung Wen Kao
Physics , 2011,
Abstract: To resolve the puzzle of the proton size raised from the recent result of muonic hydrogen Lamb shift, De R\'{u}jula has proposed that a large value of the third Zemach moment $< r^3_{p}>{(2)}$ of the proton to be the solution. His suggestion has been criticized by many groups based on the $ep$ scattering data at low $Q^2$ regime. However, if there is a "thorn" or "lump" in the electric form factor of the proton $G_{E}(Q^2)$ at extremely low $Q^2$ regime, then the third Zemach moment $< r^3_{p}>{(2)}$ would be as large as De R\'{u}jula suggested. In this article, we show that the existence of such a "thorn" or "lump" has not been completely excluded, although tightly restricted, by the current data of $ep$ elastic scattering. We also suggest a more sophisticated global fitting procedure of $G_{E}(Q^2)$ for the future fitting.
Quark effects and isospin-violation in ${}1S_0$ NN scattering
Chung Wen Kao,Shin Nan Yang
Physics , 2001,
Abstract: We present the results of the effects of various mechanisms on the quark level, including QED-QCD interference effect, on isospin violation in ${}1S_0$ NN scatterings with the new sets of strength parameters obtained by fitting to mass splittings in the baryon isomultiplets listed in the most recent PDG compilation. We also give the matrix elements of the various potential operators which would be useful to study of these charge dependent effects in finite nuclei.
The pion photoproduction in the Δ(1232) region
Chung Wen Kao,Thomas D. Cohen
Physics , 1998, DOI: 10.1103/PhysRevC.60.064619
Abstract: We investigate the pion photoproduction in the \Delta(1232) region in the framework of an effective Lagrangian including pions, nulceon and \Delta(1232). We work to third order in a small scale expansion with both $m_{\pi}$ and $M_{\Delta}-M_N$ treated as light scales. We note that in the $\Delta$ region, straightward power counting breaks as the amplitudes become very large, to deal with this problem, we suggest that the appropriate way to compare theoretical calculations with experimental data is via weighted integrals of the amplitudes through the $\Delta$ region.
The loop corrections to the parity-violating electron-proton elastic scattering
Yu Chun Chen,Chung Wen Kao
Physics , 2009, DOI: 10.1142/S0217751X09047302
Abstract: We calculate the two-boson-exchange (TBE) corrections to the parity asymmetry of the elastic electron-proton scattering in a model using the formalism of generalized parton distributions (GPDs).
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