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Haloxylon ammodendron is an excellent windproof and sand-fixing species whose shrubs are widely cultivated in arid desert areas of northwest China but are now at risk of degradation and shrinkage. Using the chlorophyll fluorescence image analysis technique, the response of photosystem II (PSII) photochemical efficiency and non-photochemical quenching capacity to sediment-carrying wind and sand-free wind (both 12 m s−1) lasting for 10, 20, and 40 min were studied with seedlings in a wind tunnel. The results indicated that the sand-free wind had little influence on the maximum quantum efficiency of PSII photochemistry, Fv/Fm, which was approximately 0.80 on average; however, the Fv/Fm decreased over exposure time in the sediment-carrying wind group, with values smaller than those in the wind-only group. The non-photochemical quenching was sensitive to wind erosion, and sediment-carrying wind could aggravate the reduction in non-photochemical quenching (NPQ). Except for the 10 min duration, the maximum quantum efficiency of PSII photochemistry after dark recovery for 15 min, Fvr/Fmr, was lower in seedlings exposed to sediment-carrying wind than in those in the wind-only group. Compared to wind-only, wind-blown sand led to a water imbalance and withering in seedlings, causing the concentration of photosynthetic pigments (when based on the fresh mass of green branches) to not decrease. With a longer exposure time to sediment-carrying wind, both the probability and extent of lignified spots occurring increased in green assimilative branches. Our results demonstrated that sediment-carrying wind at 12 m s−1 lasting for 20 min or more could cause irreversible damage to the photosynthetic apparatus of H. ammodendron seedlings. Therefore, frequent and strong sandstorms are the main disturbance factors leading to shrinkage of shrubs and limiting their self-renewal.

Swimming performance (aerobic and anaerobic) is often used to predict the ability of fish to adapt and survive. Fish raised in captivity are typically poor swimmers and have lower survival rates than wild conspecifics when released into the natural environment. We investigated the potential for exercise training to enhance the swimming performance of Schizothorax wangchiachii held in captivity. Juvenile fish (mean body mass 1.40 ± 0.13 g, mean body length 4.36 ± 0.24 cm) were trained under five different regimes [3 cm·s-1 control group (C), 10 cm·s-1 for 6 (L6) and 12 h (L12) per day and 20 cm·s-1 for 6 (H6) and 12 h (H12) per day] for 30 days and then detrained for 20 days (i.e. no training). Aerobic (i.e. critical swimming speed, Ucrit), anaerobic swimming performance (i.e. endurance time at 1.2 or 1.5 Ucrit), and morphological parameters were measured at the beginning (T0), after 30 days of exercise training (T30) and after 20 days of detraining (DT20). Aerobic exercise training significantly improved the Ucrit, endurance time at 1.2 and 1.5 Ucrit of juvenile S. wangchiachii (P < .05). After 20 days of detraining, both the aerobic and anaerobic swimming performance of the H6 and H12 groups declined and no longer differed from the control group indicating a failure to maintain improved swimming performance, whereas improved swimming performance was maintained in L6 and L12 groups. No significant difference in swimming performance was found between 6 and 12 hours training at 10 cm·s-1. Thus, exercise at close to 10 cm·s-1 for 6 h per day for 30 days or a longer time periods prior to release appears to be a suitable regime for swimming performance enhancement, potentially increasing survivability of released S. wangchiachii in wild.

DC-DC converter is a kind of power conversion equipment. Electricity is the direct power for most mechanical industrial equipment currently. However, because of the diversity of mechanical industrial equipment, electricity should be transformed through power conversion equipment. This paper presents a DC-DC boost converter with PWM control method. The hardware and the structure of the core circuit is designed and the boost principle is interpreted. The detail of the configuration circuit around is described as well.

The saliva pregnancy test apparatus is dependent on manual operation to obtain results by observing the saliva crystallization image with complex operation, how to recognize the saliva crystallization image quickly and accurately has become an important research topic. In this paper, an image recognition method on the crystallization of saliva is proposed. Firstly, gray processing on the original image, improved Otsu method is used to select the threshold and binaryzation. Then the proportion of black and white pixels is calculated to identify saliva crystal images with the percentage values. The results show that the method is simple and treatment results are accurate.

The precision of seismic reflection data does not fulfil to explore private and complex structure oil-gas pools. So we need to improve the resolution of seismic data. To achieve this, we used the inverse Q filter methods to improve the resolution for the seismic data. The results for processing the pre-stack seismic data indicated that the inverse Q filter method can improve peak frequency and frequency bandwidth. Low and middle-high frequency components in those results are reasonable, and its signal/noise ratios are obviously larger than that for other methods in middle-high frequency. Moreover, the results using various Q values indicated that the peak frequency is little added and the frequency bandwidth is expanded when Q value is reducing, but the signal/noise ratio is reducing. Moreover, the improving of the signal/noise ratio is very small when Q value is larger than 200.0, namely addition for Q value only gains reducing of the peak frequency and the bandwidth.

The conventional velocity analysis and normal moveout (NMO) are based on hyperbolic event, but the assumption of hyperbolic travel-time only applies to the situation where offset is less than or equal to the depth of reflecting interface. In recent years, in order to explore the new domain in deeper region, acquisition and processing about seismic data are developed rapidly. Maximum offset of acquisition has been reached or more than 8000 meters, and the coverage reached 100 times too. So the conventional hyperbolic normal moveout is not suitable for long cable acquisition. To solve the problems led by long array, this paper introduces the long array non hyperbolic NMO method, and it works well both in the model and practical data.

The selective transalkylation of N -methyl tertiary amines with 3,4-dibromobutenolides is described. The N -methyl group of the parent tertiary amines was replaced by alkenyl units of the butenolides; and a series of butenolide-containing tertiary enamines were obtained in moderate to good yields. Interestingly, the product 2b has shown a promising anticancer activity against HeLa cell lines (IC 50 = 0.19 μmol/L).

An efficient synthesis of 4,5-diamino-3-halofuran-2(5 H )-ones has been developed based on a sequential acylation and bisamination of mucohalic acids. The β - and γ -amination products have also been prepared with high regioselectivity. This reaction shows some advantages in terms of its simple operation and readily available but highly functionalized starting material. All products gave satisfactory IR, 1 H NMR, 13 C NMR and HRMS.

The selective transalkylation of N -methyl tertiary amines with 3,4-dibromobutenolides is described. The N -methyl group of the parent tertiary amines was replaced by alkenyl units of the butenolides; and a series of butenolide-containing tertiary enamines were obtained in moderate to good yields. Interestingly, the product 2b has shown a promising anticancer activity against HeLa cell lines (IC 50 = 0.19 μmol/L).

The reaction of O-acetylated mucobromic and mucochloric acid with excess primary and secondary amines is investigated.

In the present paper, the authors analysed 10 mineral elements in the roots of Rheum tanguticum collected from 30 different habitats. The mean concentration values of the 10 elements decreased as follows: CaMgKFeMnCrZnNiCuSe. Ca, Mg, K and Fe were abundant in this herb. Most elements varied over a wide range depending on the different habitats. The mineral element data were evaluated by principal component analysis to reveal the distribution pattern of elements in root. Four principal components (K-Ca factor, Cu factor, Mg factor and Zn-Se factor) of plant elements were selected. The authors' study provided a new scientific foundation for further studies and general application of this Chinese herb.

A hydride atomic fluorescence spectrometry has been developed for the determination of trace arsenic and mercury in medicinal animal horns. This method was simple, rapid and sensitive. The samples were digested with HNO3-HClO4(5:1), under the optimum conditions, the allowable amounts of 26 coexist elements were determined. The detection limits of this method were as follows: As 1.50 ng.mL-1, Hg 0.80 ng.mL-1. The relative standard deviations of 11 determinations were 1.2%-2.3% for As and 2.5%-4.7% for Hg. The recoveries were 98.9%-103.8% for As and 95.4%-105.0% for Hg.