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In this study, we report on the spatial and temporal distribution of seasonal snow depth derived from passive microwave satellite remote-sensing data (e.g. SMMR from 1978 to 1987 and SMM/ I from 1987 to 2006) in China. We first modified the Chang algorithm and then validated it using meteorological observation data, considering the influences from vegetation, wet snow, precipitation, cold desert and frozen ground. Furthermore, the modified algorithm is dynamically adjusted based on the seasonal variation of grain size and snow density. Snow-depth distribution is indirectly validated by MODIS snow-cover products by comparing the snow-extent area from this work. The final snow-depth datasets from 1978 to 2006 show that the interannual snow-depth variation is very significant. The spatial and temporal distribution of snow depth is illustrated and discussed, including the steady snow-cover regions in China and snow-mass trend in these regions. Though the areal extent of seasonal snow cover in the Northern Hemisphere indicates a weak decrease over a long period, there is no clear trend in change of snow-cover area extent in China. However, snow mass over the Qinghai–Tibetan Plateau and northwestern China has increased, while it has weakly decreased in northeastern China. Overall, snow depth in China during the past three decades shows significant interannual variation, with a weak increasing trend.

Dome A, the highest point on the Antarctic ice sheet at just over 4000 ma.s.l., is located near the centre of East Antarctica. Chinese National Antarctic Research Expeditions have studied ice-sheet dynamics and mass balance along a traverse route from Zhongshan station to Dome A during the austral summers from 1996/97 to 2004/05. Nineteen GPS sites were occupied on at least two occasions at approximately 50 km intervals. The purpose of the surveys was to provide accurate ice-dynamics data. A dual-frequency GPS receiver was used and each site was occupied for 1–12 hours. GPS data were processed using GAMIT/GLOBK software, and horizontal accuracies were within 0.1 m. Repeat GPS measurements provided ice velocities. The horizontal surface ice velocities increase from the summit of the ice sheet to the coast. In the Dome A area, the velocities are <10ma–1; in the plateau area, velocities range from 8 to 24 ma–1 and reach about 98.2 ma–1 at a site (LT980) near the coast. The flow directions are roughly perpendicular to the ice-sheet surface elevation contours, primarily toward the Lambert Glacier basin.

Stakes at 2 km intervals were installed in January 1997 and remeasured in February 1998, January 1999, January 2005 and during the 2007/08 austral summer along a 1248 km traverse route from Zhongshan station to Dome A, East Antarctica. Based on topographical parameters, meteorological features and the records of ∼650 stakes and six stake arrays, the route is divided into five zones. We find that the snow accumulation rate decreases with increasing altitude as one progresses inland, except in the zone 800–1128 km from the coast, where the average annual accumulation rate is higher than in the zone 524–800 km from the coast. The Dome A zone (1128–1248 km) has the lowest accumulation rate (35 kg m−2 a−1, 2005–08) due to having the highest elevation and being furthest from the coast. The surface mass balance in the region 202–1128 km from the coast exhibits no temporal change from 1999–2005 to 2005–08, but there is a change in the accumulation distribution. The zone from 202 to 524 km shows a decrease in surface mass balance from 84 kg m−2 a−1 in 1999–2005 to 67 kg m−2 a−1 in 2005–08, while the zone between 800 and 1128 km shows an increase from 67 kg m−2 a−1 in 1999–2005 to 75 kg m−2 a−1 in 2005–08.

Glacier area changes in the Pumqu river basin, Tibetan Plateau, between the 1970s and 2001 are analyzed, based on the Chinese Glacier Inventory and ASTER images. A new glacier inventory is obtained by visually interpreting the remote-sensing images and the digital elevation model. By comparing the two inventories, glacier area changes over the past 30 years are revealed. The results show that the area loss is about 9.0% and the shrinkage trend continues according to the meteorological data.

In indirect drive, reducing peak intensity of a single beam and controlling overlap of multi-beams are two opposite requirements for laser focal spot design. In this paper, an improved laser spot design technique for indirect drive built upon the geometric structures of laser propagation into hohlraum has been introduced. The proposed technique is able to generate appropriate continuous phase plate (CPP) producing a special shaped spot that can balance the opposite requirements. The corresponding CPP does not bring difficulties to the design and fabrication. Phase aberrations are more sensitive to the special shaped spot; however, it can be tolerable for the current beam control level.

The coordinates of common extragalactic radio sources will be different if the orientations of individual frames are different. If coordinates in each of the frames are in good consistence, i.e. small or non local relative deformations exist, common arcs in frames will be equal to each other (within precision) whether the orientations of the frames coincide or not. In addition, if relative deformations exist between frames, these deformations will be reflected partly on the difference of the lengths of common arcs. It is inferred that we can select candidates for primary objects by comparing the lengths of common arcs in individual frames. We call this as the Arc Length Difference (ALD) selection method.

Considering that it is unrealistic to distinguish between positions with or without deformations beforehand (Arias et al., 1988), and that an arc length difference gives us nothing definite about the consistency of a specified source in frames because of the variable values and the statistical zero mean of the differences (Li & Jin, 1994), we take the Mean value of all the Absolute Arc Length Differences (MAALD) related to each specified source as the criterion for the recognition of deformation. The large the deformation for a particular source is, the larger (statistically) the absolute value of the arc length difference or the MAALD related to this source will be. Taking all the MAALDs of all the common objects of two frames as a random series, and deleting large MAALDs in this series by means of statistics, we can select candidates for primary objects which have better internal and external consistencies in frames.

Here we make emphasis on the following two aspects of the ALD method. First, if we take all the absolute values of the arc length differences as a random series and perform statistical deletion on this series, there will come out the situation that among all the absolute values related to a specified source some will be deleted and others will be kept because of the variable value nature of the arc length difference. Therefore the characteristics of consistency of the source will be concealed and we will be faced to the ambiguous case to decide whether the source should be deleted or not. The effect of the variable value nature of the arc length difference can be avoided and the characteristics of consistency of a source is highlighted by using the mean of all the absolute values related to this source. Second, since the value of MAALD is the mean of all the absolute arc length differences related to a source, a specified arc length difference will enter into two MAALDs, so that all the MAALDs are then interweaved with one another. After one of the MAALDs is deleted, the rest will be changed accordingly. So we emphasize a progressive process to avoid a large number of sources being deleted in a single step.

Our tests show that the ALD selection method is stable and reliable. It can emphasize the characteristics of each source on the premise of the consistency of all the sources and the selection results of this method can reflect appropriately the total number of sources, the position precision, the sky coverage and so on of individual frames.

Based on 27 individual catalogues, which have been published since 60s' and consist of the positions of the counterparts of extragalatic radio sources, we have compiled a combined catalogue by means of Aoki (Aoki, S. et al. 1983) method for transferring the reference frame from FK4 to FK5 and the referred epoch from B1950.0 to J2000.0 and IERS method (Feissel, M. et al. 1988), which is used for compiling the combined catalog of radio sources. Of course, in the compiling procedure the systematic differences of Peth 70, AGK3RN, and AGK3 (Schwan, H. 1985) have been considered.

In this paper authors pointed out that the root mean square of post-residual is two or three times larger than that of normal points. It is mainly due to the ephemeris uncertainties, i.e. the uncertainties of obliquity of the ecliptic and equinox and the inaccurary of lunar love numbers adopted. At present, with exception of the corrections of ocean tide and pole tide the theoretical modeling such as earth solid tide, lunar tide, plate motion and the relativity modeling, especially the space curvature caused by the earth, have been considered to match the present observing precision in the magnitude of centimeter. The equivalent of relativity modeling used in geocentric or barycentric reference frame is further described.

In this paper we present new petrological and whole-rock geochemical data for the Palaeoproterozoic metasedimentary rocks in the upper part of the Ji'an Group within the Jiao–Liao–Ji Belt, China, as well as zircon U–Pb age dates and in situ Lu–Hf isotope data. The new data improve our understanding of the original nature of the metasedimentary rocks, further providing insights into their tectonic setting and the evolutionary history of the northern segment of the Jiao–Liao–Ji Belt. The zircons can be divided into two groups, viz., one of magmatic origin and the other of metamorphic origin. Zircon U–Pb dating gave mean or statistical peak ages for the magmatic zircons at 2035, 2082, 2178, 2343–2421, 2451–2545, 2643–2814 and 2923–3446 Ma, and mean peak ages for the metamorphic zircons at 1855 and 1912 Ma, which indicate a maximum depositional age of 2.03 Ga and two-stage metamorphic events at c. 1.91 and 1.85 Ga for the metasedimentary rocks. Geochemical data show that (1) the protoliths of these rocks were mainly sandstones, greywackes and claystones, together with some shales; (2) the main sources of the sedimentary material were Palaeoproterozoic granites and acid volcanic rocks, with minor contributions from Archaean granitic rocks; and (3) the sediments were deposited in an active continental margin setting. Moreover, along the northeastern margin of the Eastern Block of the North China Craton there is evidence of ancient crustal materials as old as 3.76 Ga, and multiple crustal growth events at 3.23–3.05, 2.80–2.65, 2.54–2.45 and 2.28–2.08 Ga.

We examined the in vitro developmental competence of parthenogenetic activation (PA) oocytes activated by an electric pulse (EP) and treated with various concentrations of AZD5438 for 4 h. Treatment with 10 µM AZD5438 for 4 h significantly improved the blastocyst formation rate of PA oocytes in comparison with 0, 20, or 50 µM AZD5438 treatment (46.4% vs. 34.5%, 32.3%, and 24.0%, respectively; P < 0.05). The blastocyst formation rate was higher in the group treated with AZD5438 for 4 h than in the groups treated with AZD5438 for 2 or 6 h (42.8% vs. 38.6% and 37.2%, respectively; P > 0.05). Furthermore, 66.67% of blastocysts derived from these AZD5438-treated PA oocytes had a diploid karyotype. The blastocyst formation rate of PA and somatic cell nuclear transfer (SCNT) embryos was similar between oocytes activated by an EP and treated with 2 mM 6-dimethylaminopurine for 4 h and those activated by an EP and treated with 10 µM AZD5438 for 4 h (11.11% vs. 13.40%, P > 0.05). In addition, the level of maturation-promoting factor (MPF) was significantly decreased in oocytes activated by an EP and treated with 10 µM AZD5438 for 4 h. Finally, the mRNA expression levels of apoptosis-related genes (Bax and Bcl-2) and pluripotency-related genes (Oct4, Nanog, and Sox2) were checked by RT-PCR; however, there were no differences between the AZD5438-treated and non-treated control groups. Our results demonstrate that porcine oocyte activation via an EP in combination with AZD5438 treatment can lead to a high blastocyst formation rate in PA and SCNT experiments.

Accurate prediction of the flow around multi-element airfoil is a prerequisite for improving aerodynamic performance, but its complex flow features impose high demands on turbulence modeling. In this work, delayed detached-eddy-simulation (DDES) and zonal detached-eddy-simulation (ZDES) was applied to simulate the flow past a three-element airfoil. To investigate the effects of numerical dissipation of spatial schemes, the third-order MUSCL and the fifth-order interpolation based on modified Roe scheme were implemented. From the comparisons between the calculations and the available experimental result, third-order MUSCL-Roe can provide satisfactory mean velocity profiles, but the excessive dissipation suppresses the velocity fluctuations level and eliminates the small-scale structures; DDES cannot reproduce the separation near the trailing edge of the flap which lead to the discrepancy in mean pressure coefficients, while ZDES result has better tally with the experiment.

Metallic glasses (MGs) are known to have high strength, but poor ductility. Prior studies have shown that plasticity in MG can be enhanced by significantly reducing their dimension to nanoscale. Here we show that, via the introduction of certain types of crystalline/amorphous interfaces, plasticity of MG can be prominently enhanced as manifested by the formation of ductile “dimples” in a 2 μm thick amorphous CuNb film. By tailoring the volume fraction and architecture of crystalline/amorphous multilayers, tensile fracture surface of MG can evolve from brittle featureless morphology to containing ductile dimples. In situ micropillar compression studies performed inside a scanning electron microscope show that shear instability in amorphous layers can be inhibited by interfaces. The mechanisms for improving plasticity and fracture resistance of MG via interface and size effect are discussed.

The impact of climate change on the variability of local discharge was investigated in a glacierized high mountain catchment located in the source area of the Ürümqi river, northwest China. We used past climate records to drive a hydrological model to simulate the discharge from 2000 to 2008. The model was then used to project future discharge variations for the period 2041–60, based on a regionally downscaled climate-change scenario combined with three stages of glacier coverage (i.e. compared to the glacier coverage in 2008): unchanged glacier size (100% glacierized), recession of half the glacier area (50% glacierized) and complete disappearance of glaciers (0% glacierized). In each scenario, snowmelt will begin half a month earlier and the discharge will increase in May. For the 100% glacierized scenario, the discharge will increase by 66 ± 35% in a smaller (3.34 km2) and more glaciated (50%) catchment and 33 ± 20% in a larger (28.90 km2) and proportionally less glaciated (18%) catchment. If the glacier area reduces by half, the discharge will decrease by 8 ± 5% and 9 ± 6%, respectively. Once the glacier disappears, the discharge will decrease by 58 ± 20% and 40 ± 13%, respectively. Together, the results indicate that a warming climate and the resulting glacier shrinkage will cause significant changes in the volume and timing of runoff.

Melt-SHS (self-propagating high-temperature synthesis), based on the SHS process and oxide reaction method, was used for preparation of TiB2/Al composites. The mass ratio of two reactants, Ti powder/TiO2, in initial powder mixture was varied from 0:1 to 1:0. The results showed that the 5 wt% TiB2/Al composites could be successfully produced by a reaction of aluminum powder, TiO2, and B2O3 in Al melt at 950 °C, while the reaction rate was slow. The addition of titanium powder helps to reduce the content of Al2O3 and destroy the coating structure of Al2O3 covered TiB2 particles, which leads to the acceleration of reaction process and improvement of particle concentration. A significant improvement was that TiB2 particles were dispersively distributed when the mass ratio of Ti powder/TiO2 was 2:3. As a result, the 5 wt% TiB2/Al composites fabricated by melt-SHS process with modified reactants ratio showed excellent tensile properties with the ultimate tensile strength as high as 114.24 MPa. Besides, the composite also showed superior ductility.

Surface texture was prepared on the ASTM1045 steel substrate before spraying. Three texturing patterns (groove pattern, square pattern, and hexagon pattern) were acquired by laser processing to investigate the influence of texturing patterns on the adhesion strength of sprayed coatings. The Ni60 coatings were prepared on the textured surface by atmosphere plasma spraying technology. Scanning electron microscopy and laser 3D microscope were used to characterize the morphology of texturing. The adhesion strength between coating and substrate was examined by the tensile test. Image pro plus software was used to calculate the contact area ratio of the textured substrate. The results show that the texturing processed substrates by laser radiation present plain area between two dimples and the protrusion around texturing, and the contact area between coating and substrate is increased. The adhesion strength of coatings with a groove pattern, a square pattern, and a hexagon pattern is 58, 33, and 47 MPa, respectively. The adhesion strength of sprayed coatings varies with the change of the texturing pattern, and it does not only depend on the contact area ratio but also on the texturing density and the texturing microstructure.