Variation of productivity and nutritive values of oat (Avena sativa) with geographical locations in Gansu Province of Northwest China under irrigation and fertilization conditions

Field experiments were conducted in low, medium and high sites; Jingqianghe, Huangzangsi and Lanzhou areas of Gansu Province, China from 2000 to 2001 to investigate the effects of geographicallocations on herbage dry matter (DM) yield and nutritive values of oat. It was found that the plant growing in Jingqianghe area yielded the highest forages (16046.0 DM/hm2) at high accumulation rate(300 kg ha-1d-1) and within long growing season (120 d), the plant growing in Huazangsi area produced medium quantity of forages (13020.3 DM/hm2) at low accumulation rate (200 kg ha-1d-1) but within long growing season (120 d), and the plant growing in Lanzhou area had the lowest forage yield (12505.7 kg DM/hm2) at relatively high accumulation rate (270 kg ha-1d-1) but within extremely short growing season (50 d). The highest seed production of 3789.3 kg DM/hm2 annually was observed in Huangzangsi area, the lowest seed production of 933.7 kg DM/hm2 annually was found in Jingqianghearea, and the medium seed production of 1632.7 kg DM/hm2 annually was recorded in Lanzhou area. The plant growing in high site of Jinqianghe area concentrated more (P 0.05) in in sacco degradability (ISD) of the plant among different growing sites was observed in the whole growing season. It was concluded from this study forage productionshould be conducted in high site of Jingqianghe area and seed production of oat should be conducted in low site of Lanzhou area with enough water and fertilizer supply

Solar modulation of cosmic ray intensity and solar flare events inferred from (14)C contents in dated tree rings

The delta 14C values in 42 rings of a white spruce grown in Mackenzie Delta was measured as a continuing effort of tracing the history of solar modulation of cosmic ray intensity. The delta 14C values in six rings were measured, in search of a 14C increase due to two large solar flares that occurred in 1942. The results are presented

Improper ferroelectricity in ultrathin hexagonal ferrites films

Suppression of ferroelectricity in ultrathin films of improper ferroelectric hexagonal ferrites or manganites has been attributed to the effect of interfacial clamping; however, the quantitative understanding and related phenomenological model are still lacking. In this work, we report on the paraelectric-to-ferroelectric phase transition of epitaxial h-ScFeO3 films with different thicknesses through in situ reflection highenergy electron diffraction. Based on the interfacial clamping model and the Landau theory, we show that the thickness-dependence of the ferroelectric Curie temperature can be understood in terms of the characteristic length of an interfacial clamping layer and the bulk Curie temperature. Furthermore, we found that the critical thickness of improper ferroelectricity is proportional to the characteristic length of the interfacial clamping layer. These results reveal the essential role of mechanical clamping from interface on the improper ferroelectricity of hexagonal ferrites or manganites and could serve as the guidance to achieve robust improper ferroelectricity in ultrathin films

A study on the extraction and purification technology of tea sapogenin

In order to extract and purify tea sapogenin, first the extraction liquid is obtained using mechanically pressed tea-seeds as raw material, which will be decreased by organic solvent. When the conditions like the methanol volume fraction is 75v/v, solid-liquid is 1:4 and the ultrasonic frequency is 25.8 Hz, extract them for 30 min. After this, collect the extraction liquid and slowly add in Hz-841 macroporous resin column, then elute it with 0.3% NaOH. The third step is to elute with ethanol of different concentrations after the coloring pigment is got rid of, and then detect it with thin layer chromatography (TLC). It is discovered that there is only tea sapogenin in the 35 – 95v/v ethanol elution liquid. The last step is to collect the 95% ethanol elution liquid and vacuum condense it; and then tea-Tea sapogenin with a purity of 96% can be obtained

Probe of Spin Dynamics in Superconducting NbN Thin Films via Spin Pumping

The emerging field of superconductor (SC) spintronics has attracted intensive attentions recently. Many fantastic spin dependent properties in SC have been discovered, including the observation of large magnetoresistance, long spin lifetimes and the giant spin Hall effect in SC, as well as spin supercurrent in Josephson junctions, etc. Regarding the spin dynamic in SC films, few studies has been reported yet. Here, we report the investigation of the spin dynamics in an s-wave superconducting NbN film via spin pumping from an adjacent insulating ferromagnet GdN layer. A profound coherence peak of the Gilbert damping is observed slightly below the superconducting critical temperature of the NbN layer, which is consistent with recent theoretical studies. Our results further indicate that spin pumping could be a powerful tool for investigating the spin dynamics in 2D crystalline superconductors.Comment: 11 pages, 4 figures, and S

Effect of Mg/B ratio on the superconductivity of MgB2 bulk with SiC addition

To improve the self-field critical current density (Jc) and critical temperature (Tc) in SiC-doped MgB2, optimization of the nominal Mg/B mixing ratio has been performed. The effects of the nominal Mg/B mixing ratio (x:2) on the superconductivity, Raman spectra, current transport properties, and flux pinning mechanisms in MgB2 with 10 wt.% SiC doping were investigated systematically, with x varied from 1 to 1.2. It has been found that the sample with the Mg/B ratio of 1.15:2 exhibited the best Jc performance for all fields (0–8.5 T), and its Tc was also enhanced. The optimized Mg/B ratio diminished the interband scattering caused by Mg or B vacancies, and in turn, increased Tc. The connectivity and disorder were increased in the Mg1.15B2 sample. Both of these were responsible for the improved Jc under all the fields examined

Atomic entanglement sudden death in a strongly driven cavity QED system

We study the entanglement dynamics of strongly driven atoms off-resonantly coupled with cavity fields. We consider conditions characterized not only by the atom-field coupling but also by the atom-field detuning. By studying two different models within the framework of cavity QED, we show that the so-called atomic entanglement sudden death (ESD) always occurs if the atom-field coupling lager than the atom-field detuning, and is independent of the type of initial atomic state

The macro-behavior of agents' opinion under the influence of an external field

In this paper, a model about the evolution of opinion on small world networks is proposed. We studied the macro-behavior of the agents' opinion and the relative change rate as time elapses. The external field was found to play an important role in making the opinion $s(t)$ balance or increase, and without the influence of the external field, the relative change rate $\gamma(t)$ shows a nonlinear increasing behavior as time runs. What's more, this nonlinear increasing behavior is independent of the initial condition, the strength of the external field and the time that we cancel the external field. Maybe the results can reflect some phenomenon in our society, such as the function of the macro-control in China or the Mass Media in our society.Comment: 8 pages, 3 figure

Matter loops corrected modified gravity in Palatini formulation

Recently, corrections to the standard Einstein-Hilbert action are proposed to explain the current cosmic acceleration in stead of introducing dark energy. In the Palatini formulation of those modified gravity models, there is an important observation due to Arkani-Hamed: matter loops will give rise to a correction to the modified gravity action proportional to the Ricci scalar of the metric. In the presence of such term, we show that the current forms of modified gravity models in Palatini formulation, specifically, the 1/R gravity and $\ln R$ gravity, will have phantoms. Then we study the possible instabilities due to the presence of phantom fields. We show that the strong instability in the metric formulation of 1/R gravity indicated by Dolgov and Kawasaki will not appear and the decay timescales for the phantom fields may be long enough for the theories to make sense as effective field theory . On the other hand, if we change the sign of the modification terms to eliminate the phantoms, some other inconsistencies will arise for the various versions of the modified gravity models. Finally, we comment on the universal property of the Palatini formulation of the matter loops corrected modified gravity models and its implications.Comment: 11 pages, 1 figures, References adde