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Isothermal compression tests of 25vol% B4Cp/2009Al composite have been carried out at temperatures ranging from 300 °C to 500 °C and strain rates ranging from 0.001 s−1 to 1 s−1. The results show that high-temperature flow stress of the composite decreases with the increase of deformation temperature and the decrease of strain rate. The flow stress has been corrected by friction and the friction corrected stress is lower than experimental values. The influence of friction becomes more obvious with decreasing temperature and increasing strain rate. Then a constitutive equation considering the effect of strain on material constants (i.e. α, n, Q and A) is developed on the basis of Arrhenius type equation. Compared with the experimental results, the flow stress calculated by the constitutive equation possesses a high precision with the correlation coefficient of 0.992. Higher temperature and lower strain rate is beneficial to hot deformation of B4Cp/2009Al composite.

Coal plays an important role in the Chinese energy source. The heavy metals released from combustion process stay in the environment and are not easily degraded. This paper examines 8 coal samples from China. It explores the content, characteristics, transformation and control of heavy metals through the microwave digestion, sequential chemical extraction, static burning test and X-ray diffraction (XRD) methods. The zinc (Zn) and cadmium (Cd) in coal mainly exist in exchangeable, sulfide, and residual forms. The arsenic (As) content is mainly present in the sulfide binding state. For these three elements, degrees of organic speciation are not considered to be important and the residue speciation mainly occurs in coal ash. After coal combustion, the heavy metals in coal ash are relatively enriched, and the harm to the environment cannot be ignored. Most of the Cd, As and Zn residues are released into the atmosphere and their volatility rates can be ordered as follows: As > Zn > Cd. There are significant differences in mineral composition between the main phases and mineral carriers of heavy metals in coal and ash. Based on these differences, modified calcium carbonate (CaCO3) is used as an additive. In orthogonal experiment, the optimal parameters for treating heavy metals are the temperature (1000 °C), metal salt (Al2(SO4)3), and ion ratio (γ = 15). Under this condition, the volatilization rates of heavy metals (As, Cd and Zn) decreased remarkably.

Qingnaopian has been used in traditional Chinese medicine for treating central nervous system (CNS) injury and inflammatory diseases. The aim of this study was to investigate the effects of Qingnaopian in concussion mice. C57BL/6 mice were used to establish the mild Traumatic Brain Injury (mTBI)/ concussion using the weight-drop techniques. Animal behavioral experiments righting reflex response and locomotor activity were assessed. The expression of pro inflammatory cytokines, including tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), IL-1 and Glial fibrillary acidic protein (GFAP) were assessed by enzyme-linked immunosorbent assay (ELISA) and Western blot method, respectively. SPSS 19.0 software was used for statistical analysis. The results showed that righting reflex time and locomotor activity were higher in model group compared with those in control group. Qingnaopian treated mice had lower pro inflammatory cytokines, such as IL-1, IL-6 and TNF-α with alleviated GFAP. In short, Qingnaopian treatment improved GFAP induced by blow to head and inflammatory cytokines in concussion mice.

Hastelloy C-276 was subjected to low strain deformation and then annealed at 1100 °C for different time. The ∑3 and ∑9 boundary percentages and grain boundary plane distributions were characterized by electron back-scatter diffraction (EBSD) and a five-parameter analysis method. The results show that the ∑3 boundary evolves towards a more exact coincident-site lattice (CSL) misorientation and the ∑3 boundary plane is closer to low surface energy plane {111} with the increasing of annealing time. This is consistent with fine tuning mechanism. While the population of incoherent ∑3 boundary is increasing, the proportion of ∑9 boundary with larger deviations increase, too. And the distributions of grain boundary density planes for ∑9 boundary are more intensive on the whole [110] zone.

Hot compression tests were conducted using a Gleeble–3500 thermomechanical simulator to investigate the effect of hot deformation conditions on dynamic recrystallization (DRX) of GH690 alloy. The results show that the DRX process of GH690 alloy is controlled by deformation temperature and strain rate. Under the investigated condition at a constant strain rate ranging from 0.001 to 1 s −1 , the temperature needed for fully dynamic recrystallization increases with the increases of strain rate, and the size of dynamically recrystallized grain is greatly affected by the increase of deformation temperature. The values of critical strain for the initiation of DRX can be determined from the strain-stress curves, and a equation related to the Zener-Hollomon Parameter is as follows: ɛ c =1.135×10 −3 Z 0.14233 . A discontinuous dynamic recrystallization (DDRX) mechanism with nucleation of bulging of the original grain boundaries is the operating nucleation mechanism of DRX of GH690 alloy. A continuous dynamic recrystallization (CDRX) with subgrain rotation, which can only be considered as an assistant nucleation mechanism of DRX, occurs simultaneously with the DDRX.

Aboveground litter is a key factor for carbon sequestration in territorial ecosystems as well as soil conservation in erosion-derived,degraded areas.On the Loess Plateau,understanding aboveground litter contribution to soil respiration(LC) enhances the investigation of soil C dynamics as a consequence of litter accumulation accompanying vegetation restoration.Aboveground litter manipulation was carried out in a 26-year-old black locust plantation(Robinia pseudoacacia) in the Wangdong catchment in the gully region of the Loess Plateau.Litter treatments consisted of no litter(NL,aboveground litter excluded from plots),control(CK,normal litter inputs allowed),and double litter(DL,aboveground litter doubled by adding litter removed from NL plots).There were three plots in each treatment,and the plot size was 1.5 m×1.5 m.Three polyvinyl chloride(PVC) collars were installed along the diagonal in each plot.Soil respiration rates(Rs) were measured approximately once every two weeks in 2009 decreasing to once every four weeks in 2010 during the period of April to October in both years using a Li-8100 closed chamber system(Li-COR,Lincoln,NE,USA).In total,Rs was measured on 19 occasions during the two-year period.Concurrent with each respiration measurement,soil temperature at the 5-cm depth was measured using a Li-Cor thermocouple while soil moisture content at the 5-cm depth was also measured using a hand-held frequency-domain reflectometer(ML2x,Delta-T Devices Ltd,UK) at five locations close to the outer edge of each PVC collar.During the experimental period,the mean Rs in CK was 3.23 μmol m-2 s-1.DL significantly increased Rs in CK by 26%(P = 0.091) while NL significantly decreased Rs in CK by 22%(P=0.099).The maximum difference between the Rs of DL(or NL) and the Rs of CK occurred from July to September when air temperatures were high and rainfall was sufficient.Soil temperatures showed no treatment differences(P=0.48) but the difference of soil moisture contents within treatments was significant(P 0.01).The cumulative CO2-C emissions from NL,CK and DL were 631,787 and 973 g C m-2 a-1,respectively.The Rs of NL,CK and DL had significant exponential correlation(R2=0.81 to 0.90;P 0.0001) with soil temperature but had unclear relationships with soil moisture.The temperature sensitivity of soil respiration,Q10,in NL,CK and DL was 1.92,2.29 and 2.31,respectively.And annual mean contribution rate of aboveground litter to soil respiration was 20%.Correlation analysis showed that litter contribution on every measurement day had significant positive correlativity with soil temperature(r=0.54,P 0.05) or moisture(r=0.68,P 0.05).The aboveground litterfall was 213 g C m-2 a-1,which was greater than the release of C from respiration caused by aboveground litter(156 g C m-2 a-1).This result has strong implications for soil C storage,indicating that aboveground litter accumulation in this young black locust plantation may be expected to continue contributing to the carbon pool in the ecosystem undergoing vegetation restoration and soil conservation measures on the Loess Plateau,at least in the near future.

The functional magnetic resonance imaging (fMRI) based on blood oxygen level dependent (BOLD) contrast has emerged as one of the most potent noninvasive tools for mapping brain function and has been widely used to explore physiological, pathological changes and mental activity in the brain. Exploring the nature and property of BOLD signal has recently attracted more attentions. Despite that great progress has been made in investigation of the characteristics and neurophysiological basis, the exact nature of BOLD signal remains unclear. In this paper we discuss the characteristics of BOLD signals, the nonlinear BOLD response to external stimuli and the relation between BOLD signals and neural electrophysiological recordings. Furthermore, we develop our new opinions regarding nonlinear BOLD response and make some perspectives on future study. *Supported by National Natural Science Foundation of China (Grant Nos. 30570538, 30400103 and 30470517)