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For effectively predicting the tank failure time and analyzing the key elements influencing the reliability of corroded bottom plates, this article presents a model for calculating the reliability of corroded tank bottom plates based on a hierarchical Bayesian corrosion growth model. Firstly, the growth of corrosion defect depth is expressed by the gamma process, and the hierarchical Bayesian model is used to calculate the corrosion depth growth. After that, the reliability calculation model of the corroded tank base plate is established by combining the results of the hierarchical Bayesian model with the stress-strength interference theory, and the three uncertain factors of the base plate thickness, radius, and yield strength are considered in the model. Finally, the reliability assessment and sensitivity analysis of corroded bottom plate are carried out. The results show that the proposed reliability calculation model can provide more accurate failure state prediction results than the reliability calculation model which only considers the influence of corrosion depth, and can provide reference for reducing the failure rate of tank floor and reasonably formulating the maintenance plan of tank floor.

Zeaxanthin is a carotenoid, a dihydroxy derivative of β-carotene. Zeaxanthin has antioxidant, anti-inflammatory, anticancer, and neuroprotective properties. In this study, Yarrowia lipolyticawas used as a host for the efficient production of zeaxanthin. The strain Y. lipolyticaPO1h was used to construct the following engineered strains for carotenoid production since it produced the highest β-carotene among the Y. lipolyticaPO1h- and Y. lipolyticaPEX17-HA-derived strains. By regulating the key nodes on the carotenoid pathway through wild and mutant enzyme comparison and successive modular assembly, the β-carotene concentration was improved from 19.9 to 422.0 mg/L. To provide more precursor mevalonate, heterologous genes mvaEand mvaSMTwere introduced to increase the production of β-carotene by 27.2% to the yield of 536.8 mg/L. The β-carotene hydroxylase gene crtZwas then transferred, resulting in a yield of zeaxanthin of 326.5 mg/L. The oxidoreductase RFNR1 and CrtZ were then used to further enhance zeaxanthin production, and the yield of zeaxanthin was up to 775.3 mg/L in YPD shake flask.

Quorum sensing (QS) system can dynamically control the expression of proteins along with the cell growth. The promoting period of QS system has been little focused on until now. In this study, a self-induced dynamic regulated expression (SIDRE) system was constructed in Escherichia coli. To enable the system suitable for the expression of enzymes, promoter engineering was used to obtain PluxImutants. To test the SIDRE system, alginate lyase AL493 and esterase Est7 were used as target protein for expression. The enzyme activity of alginate lyase and esterase reached 96.38 % and 106.71 % of the control strains containing the T7promoter. In high-density fermentation, the activity of alginate lyase expressed by the SIDRE system with PluxI(T-38C) as promoter was 4.34-fold of that expressed by the T7promoter. Therefore, the PluxImutants with different promoting periods and/or different strengths show great potential in both laboratory and industrial scale for protein expression.

Frequency converters are widely used in power grids, motor speed regulation, and other fields. When the voltage level is above low voltage and the workspace is limited, traditional frequency converters mostly adopt the power frequency transformer to connect to the power grid. But the structure has the problems of bigger volume and complexity. To solve these problems, this paper proposes a three-stage topology structure of high-frequency isolation type of dual-PWM variable frequency speed regulation based on three-phase rectification, single active isolated DC/DC converter, and three-phase inverter, and analyzes its power transmission characteristics in detail. And a new method that combines high-frequency electrical isolation and frequency conversion is discussed. Then, the control strategies of the new method are also described. Lastly, simulation and experiment are constructed to verify the new design method is correct and feasible, and that the steady and dynamic characteristics of the three-stage high-frequency isolated frequency converter are better.

The history and mechanisms of dust storms in northern China remain unclear owing to the paucity of reliable long-term, high-resolution geological records. In this study, we reconstructed the dust storm history of the last ~500 years in northern China, based on sedimentary coarse fraction (>63 µm) of a well-dated core from Lake Daihai, Inner Mongolia. The high-resolution data reveal three intervals of frequent dust storms: AD 1520–1580, AD 1610–1720, and AD 1870–2000. The dust storm events in the Lake Daihai area were broadly synchronous with those inferred from other historical or geological records and generally occurred during cold intervals. Changes in the intensity of Siberian High and the westerlies modulated by temperature variations are the likely major factors controlling dust storm dynamics. An interesting feature is that although the intensities of dust storms have been systematically increased during the recent warming period, a clear decreasing trend within this period is evident. The recent increase in average dust storm intensity may be ascribed to an increase in particle supply resulting from a rapid increase in human activity, whereas the weakening trend was likely caused by decreases in average wind speed resulting from the recent global warming.

Single-phased and dual-emissive nanocrystals with broad emission are attractive fluorescent materials for optoelectronic devices due to their unique properties. Until now, the effect of different metallic cations and inorganic anions on III–V group quantum dots (QDs) concerning luminescence features and crystalline growth has been less explored. In this work, dual-emissive InP/ZnS QDs single-doped with transition-metal compounds (Cu2+, Ag+, or Mn2+) are synthesized to compare their optical and morphological properties. The corresponding doping concentrations to realize dual emission with comparative intensity for Cu, Ag, and Mn are 0.8, 6, and 80%, which vary greatly and might be attributed to different precursor reactivities. As for the morphological and internal structures, transmission electron microscopy (TEM) images indicate that transition-metal ions have no obvious effect on the morphological properties and a higher concentration of chloride anions binding with an In-rich interface could conduce to a homogeneous distribution and triangular growth through the comparison of different metal chlorides as precursors. X-ray photoelectron spectroscopy (XPS) results further demonstrate that the high-resolution In 3d spectrum of Mn-doped InP/ZnS QDs with MnCl2is mainly dominated by In–P bonds, indicating fewer intermediate chemical states. These results concerning well-defined InP/ZnS QDs could promote more diverse insight into surface chemistry and help to better understand the growth mechanism, thus making it possible to regulate InP/ZnS QDs into desired formats for different practical applications like white light-emitting diodes (LEDs).

The Valley of Kashmir in the western Himalayas holds a large number of Neolithic sites that are part of a loosely affiliated group of prehistoric cultures occupying mountains and valleys in the north of the Indian subcontinent – the Northern Neolithic. Despite extensive excavations at several sites in the 20th century, full reports on key sites are still lacking. As a result of this a number of issues have arisen, including a poorly resolved internal chronology based in part on relative dating of ceramics, as well as unclear or speculative links to neighbouring cultures. This study reports new absolute dates, botanical materials and ceramic analyses resulting from preliminary survey and testing work aimed at rectifying these problems. A thorough synthesis of previously reported excavation data is also provided, and considered alongside the newly reported material. This has allowed us to contextualise the development of the Neolithic in Kashmir against a growing number of recent studies on the spread of early dry-farming agricultural villages in the mountain zones of South Asia. The long term cultural and economic stability of the Northern Neolithic in Kashmir has allowed us to situate it as an important niche within a wider network of agriculturalist-pastoralist exchange taking place between the mountain zones and the settled areas of Inner Asia during the 3rd- 2nd millennia BCE.

A sensitive and selective fluorescent probe for the cadmium ion (Cd2+) was developed based on the aggregation-induced emission enhancement (AIEE) of Zn–Ag–In–S quantum dots (ZAIS QDs). The QDs were synthesized by a convenient hydrothermal method with l-cysteine as ligands, with the average size of 3.2 nm and the emission peak at 520 nm. The interference study indicated the good selectivity of the probe. It has a broad detection range from 25 μM to 2 mM and the detection limit is 1.56 μM. AIEE is triggered by the interaction between Cd2+and thiol groups on the surface of QDs, which causes weaker electrostatic repulsion between QDs and the passivation of surface defects. To the best of our knowledge, this is the first report on the AIEE of quaternary QDs. The method was successfully applied to the determination of Cd2+in water samples with recoveries between 98.1% and 103.3%. This work shows its potential as a candidate for Cd2+detection and provides a new understanding of AIEE.

Mercury emitted from direct combustion of high-mercury coal does great harm to the environment. To make good use of high-mercury coal, it is necessary to study the occurrence characteristics of mercury in coal and high-efficient methods of mercury removal. In this paper, high-mercury coal of Guizhou Province of China was taken as an object to study the nature of mercury in coal and the rule of mercury removal by dry preparation method. Mercury mainly distributes in the medium and high density fractions, and has a good affinity with silicon, aluminum, iron, titanium, potassium, calcium, zinc, sodium and magnesium. It exists in minerals formed by these elements and presents significant correlation with ash in coal. After the high-mercury coal is separated by air dense medium fluidized bed, mercury content of clean coal is reduced to 1/10 of raw coal, while mercury content of gangue is increased to 3 times that of raw coal. This indicates that mercury in raw coal is rejected greatly by ADMFB and enriched in high-density fractions. The rates of ash removal and mercury removal decrease with the density and present a very high correlation.

Palaeobotanical studies at Qasim Bagh, a site of the Northern Neolithic culture in the Kashmir Valley, India, have produced important new data on the spread of agriculture across Inner Asia, and on the cross-transmission of Chinese and West Asian cultivars. Directly dated broomcorn millet (Panicum miliaceum) and compact wheat (Triticum aestivum), and a series of charcoal dates suggest that the Valley of Kashmir was integrated into a wider network of crop exchange in the mountainous regions of South and Central Asia from at least the 5th/4th millennium BP transition. The evidence of Qasim Bagh supplements recent data from other Central Asian sites which suggest that exchange of East and West Asian cultivars took place earlier than previously believed.

A well-preserved outer coffin, several hundred years old, was discovered under waterlogged conditions in the ancient Qian Zhang Tomb located within Wuxi, an old eastern Chinese city in southern part of Jiangsu Province. Wood anatomy was employed to identify the tree species used to build this ancient outer coffin. The results showed it was constructed of sturdy Chinese fir (Cunninghamia lanceolata). In addition, gas chromatography–mass spectrometry (GC-MS) was undertaken to examine the chemical composition of wood extract. The analysis indicates that cedrol, a sesquiterpene alcohol found in the essential oils, was the major compound of the extract and apparently a key factor responsible for the outstanding durability of this wood. A review of Chinese fir uses recorded in ancient Chinese literature is presented for historical context, along with a list of known archaeological sites that have contained remains of this conifer species in China. A hypothetical explanation for its selection as a coffin construction material by the noble family of Qian Zhang is also discussed.

Astaxanthin is a high-value red pigment and antioxidant widely used in the pharmaceutical, cosmetic, and food industries. However, the hydrophobicity of astaxanthin causes its low bioavailability. Glycosylation can substantially increase the water solubility of astaxanthin, thus enhancing its bioavailability, photostability, and biological activities. In this study, we report for the first time the heterologous production of glycosylated astaxanthin in Yarrowia lipolytica. By appropriate removal of the chloroplast transit peptide, carotenoid 4-hydroxy-β-ring 4-dehydrogenase (HBFD) and carotenoid β-ring 4-dehydrogenase (CBFD) from Adonis aestivaliswere expressed in a β-carotene-producing Y. lipolyticastrain, resulting in astaxanthin production with a yield of 0.59 mg/L, 0.05 mg/g DCW. This is the first time to successfully construct a plant-derived astaxanthin synthesis pathway in yeast. Modularized assembly of CBFD and HBFD, replacement of the promoter upstream CBFD, increasing the precursor β-carotene supply, and regulating the expressions of CBFD and HBFD led to a 4.9-fold increase in astaxanthin production (3.46 mg/L). Finally, introduction of crtXfrom Pantoea ananatisATCC 19321 into the astaxanthin-producing strain enabled glycosylated astaxanthin production, and the yield reached 1.47 mg/L, which is the highest yield of microbially produced glycosylated astaxanthin reported to date.

To protect mining areas from electrical fire, it is very important to install electrical fire monitoring system to ensure safety in development of mineral resources and for buildings. In this paper, design for electrical fire monitoring and detection system with optional sensor modules has been proposed. In addition, necessity and suitability of electrical fire monitoring and detection system with optional sensor modules in mining areas have been reviewed. The designed electrical fire monitoring and detection system suitable for work environment of mining industry is composed by host-computer monitoring software and slave-computer detectors. Monitoring detectors are manufactured by using embedded technology. External shells deployed have superior enclosure performances and explosion-proof properties. It is easy to install and maintain the system. In general, the system has reached, or even exceeded standards specified in national standards for performances and appearances of such devices. Test results show application of electrical fire monitoring and detection system can effectively enhance monitoring intensity over the mining areas and provide reliable guarantee to ensure orderly development of mineral resources and to protect physical and property safety of citizens in these areas.

Abstract: In this paper, the impact of the viaduct on flow and traffic exhausting particles dispersion within urban street canyons was numerically simulated using a computational fluid dynamics (CFD) model. Two-dimensional flow and dispersion of particles from traffic exhausts were modeled using the standard k-∈ turbulence model. The street canyons with a viaduct at different widths and different heights above the ground are simulated. The results show that the airflow in street canyon is evidently influenced by the viaduct: The position of the main vortex center is changed, especially there are two strong vortexes when the viaduct is placed at 10 m height above the ground. It is found based on the study of the particles number concentrations (PNCs) that the viaduct may mitigate the pollution level in the street canyon sometimes. The impact of the viaduct width on PNCs is stronger than that of the height. The study of PNDs reveals that the mean PNCs at the wall of upwind building increase when a viaduct is placed in street canyon. In addition, it is found based on the study of mean particles residence time (PRT) that the removal of the particles strongly correlates to the mean PNCs. The results indicate that the viaduct is an important factor to influence the flow patterns and particles dispersion in street canyons.

More and more infrared imaging systems were applied in military and civil fields and the performance of detecting dim target is one important index for infrared imaging system. The performance of the method based on background suppression is declined with many false alarms and even loss target in image with clutter background. In order to improve the performance of dim target detection, the method base on target enhance is developed. In this paper, after analyzing the grey value distribution of target, background and noise in local area, the pixel's shape parameter was defined, maximum strategy was used to obtain one size of pixel's shape parameter, and enumerate strategy was used to search the possible target size. And then, one character filter based on shape parameter was designed to enhanced target and suppress clutter background. Compared with the method based on background suppression, experimental results show that proposal method is effective to enhance target and suppress clutter background.

Concerning the target losing problem caused by partial occlusion, uneven illumination and so on during the image tracking procedure by traditional algorithms, a new tracking method based on robust similarity measurement criteria is proposed in this paper. The measurement is carried out with the original gray image pair with no preprocessing such as feature extraction. First, a two-dimensional joint distribution histogram is set up to describe the gray value change between the pixel in the reference and its corresponding pixel in the real image. Then, the law of data distribution under uneven illumination and partial occlusion is concluded. At last, a strategy based on Hough transformation is adopted to calculate the measurement value on the joint histogram. The method is robust for the uneven illumination. And small partial occlusion has little influence on the output value of the similarity measurement. Comparing experimental results show the new method's efficiency.

Active learning is typically limited by the small sample problem which makes the resulting classifiers perform poorly, especially in the initial stages. To overcome this problem, in this paper, a novel framework - graph-incorporated active learning - is proposed, in which the selection pool is regarded as a graph. Its graph structure is applied to both improve sample selection criterion and provide the learner enough pseudo-labeled samples. By comparing with the state-of-theart technique, the experiments on benchmark datasets show that the improvement of the proposed method is significant, i.e., it can solve the small problem well. The framework is combined with, but is not limited to, SVM.

•A Micro-CT scan and 3D reconstructed images were applied in the present study.•This necklace reflects a high level of plants cognition and the pursuit of aesthetics by Yanghai people during the 1st millennium.•The discovery of Nitrariafindings in China were summarized and reviewed in the present paper.

The micro-proton induced X-ray emission (micro-PIXE) spectrum of a single aerosol particle (SAP) was considered as its fingerprint for tracing its origin. A proton microprobe was used to extract fingerprints of SAPs. Environmental monitoring samples of PM10were collected from a heavy industrial area of Shanghai and were analyzed by proton microprobe for finding their pollution sources. In order to find the sources of SAPs collected from environmental monitoring sites, a fingerprint database of SAPs collected from various pollution sources was established. The origins of samples collected through environmental monitoring were identified by comparison of the micro-PIXE spectra of SAPs with those of SAPs in the fingerprint database using a pattern recognition technique. The results of this study show that most of the measured PM10is derived from metallurgic industry, soil dust, coal combustion, automobile exhaust, and motorcycle exhaust. The study also shows that the proton microprobe is an ideal tool for the analysis of SAPs. The unidentified particles of PM10are classified into seven classes by hierarchical cluster analysis based on the element peak intensity in the spectra.

Abstract: A synchrotron radiation X-ray fluorescence microprobe analysis technique was used to scan a slice of the femoral head from its periphery to its center, via cartilage, compact, and spongy zones in order to determine the distribution and the way inorganic substances are lost in bone tissue. The sample preparation and experimental apparatus are described in detail. The quantitative computerized tomography of elemental distribution, such as Ca, P, K, Fe, Zn, Sr, and Pb in bone slice tissue, including cartilage, substantial compact, and substantial spongy, is investigated. Combined with the correlation among, P, K, Zn, Sr, and Ca, the route of loss of minerals and the physiological functions of some metal elements in bone are also discussed.

Abstract: Diabetes mellitus is characterized by hyperglycemia and is closely related to trace elements. Quite a few pregnant women suffer from impaired glucose tolerance (IGT) or gestational diabetes mellitus (GDM). Investigation of the changes of elemental contents in serum of the pregnant women with IGT and GDM is significant in the etiological research and cure of the diseases. In the present work, the elements Cu, Zn, Ca, Sr, Mg, P, Fe, and Al in the serum of pregnant women were determined. The elemental contents in different experimental groups were compared. Also, the correlation between elemental contents and gestational period was observed. The results showed that compared with normal pregnant women, the Cu contents in serum of pregnant women with GDM increased, but Zn contents had a decreasing trend. In addition, for all pregnant women, the Ca contents in serum had an obvious inverse correlation with gestational period.

Abstract: This article deals with an osteoporosis model using New Zealand rabbits in order to study the function of inorganic elements for women patients with osteoporosis. Thirty cases of iliac crests were collected and determined using the neutron activation analysis technique. The results show that the fluorine concentrations in the experimental group are higher than those in the control group and that the magnesium concentrations are significantly lower (p<0.001), but the concentrations of potassium, sodium, calcium, barium, manganese, and strontium show no significant differences. Combined with the serum biochemical markers of bone formation and resorption, the physiological functions of some metal elements in bone are also discussed.

Abstract: More than 30 aerosol samples were collected from 1 place near Zaojiaban Road (downtown of Shanghai) and 1 village near Jiading country (suburb) by a stacked-filter air sampler. The coarse particulates (>2.5 m) and the fine particulates (PM2.5) and their unsoluble parts were analyzed by proton-induced X-ray emission. The cytotoxicity of particulates from the two places was evaluated by malondialdehyde (MDA) and thiazolyl blue (MTT) methods. The results show that the transition metal Fe, Cr, and Mn compounds from downtown are more easily soluble than those from the suburb, both in coarse and fine particulates, and the S content is much higher in particulates from downtown than that from the suburb. The cytotoxicity of the particulates from downtown is higher than that from the suburb and the cytotoxicity of acidified particulates is significantly higher than that of the controls. Because there are higher-soluble transition metal compounds that can induce free radicals in acidified particulates, the soluble transition metals may be one of the main factors for cytotoxicity.

Abstract: Gestational diabetes is one of the most common diseases in pregnancy. In the present work, the possible relationship between serum selenium concentration and gestational diabetes was investigated. Blood samples of 234 pregnant women were collected, including 98 subjects with impaired glucose tolerance (IGT), 46 subjects with gestational diabetes mellitus (GDM), and 90 normal pregnant women (NPW). An additional 17 samples of normal women of fertile age (NW) were collected for comparison. The hydride generation atomic fluorescence spectrometry was used for selenium determination. The mean serum selenium levels obtained for each group were 0.07410.0167 mg/L for NPW, 0.06310.0132 mg/L for IGT, 0.06350.0120 mg/L for GDM, and 0.1080.0170 mg/L for NW. Serum selenium levels were significantly lower in pregnant woman with IGT (p<0.001) and GDM (p<0.001) than in NPW. Furthermore, an inverse correlation between the serum selenium concentration and the gestational period was also observed. Selenium supplementation during gestation for pregnant women, especially with IGT and GDM, should be considered.

AbstractA set of quadral-electrode DC input voltage measure equipment was built up to detect the electrical resistance of Sb–Bi single-phase alloy. The results suggest that Sb–5%wt Bi undergoes structural transition in the temperature range of 730–750°C. By overheating the melt to different temperatures and then cooling to 690°C after a period of time, the samples are directionally solidified in a Bridgeman-type furnace. It is found for the first time that after heat treatment of the melt, the solid/liquid interface morphology shows significant variation depending on the speciic heat treatment. Also, in Ag–Cu, Al–Cu systems, bicrystal growth with different orientation is found to have different interface morphologies after heat treatment. It is believed that the evolution of the cluster size distribution in the melt contributes to these phenomena.

Abstract: The influence of γ-irradiation on properties of METGLAS 2605S2 and FC3-1 Fe78B13Si9 has been investigated by Mssbauer spectroscopy, positron annihilation technique as well as bending test. The ductility and orientation of magnetization were changed by γ-irradiation. They probably correlate with the change of microscopic free volume and release of stress in the ribbon, respectively.

Mössbauer spectra of FeCl3-doped polyacetylenes [CH(FeCl3)y]x (y=0.010, 0.057) have been measured at temperatures of 300, 243, 208, 143, 108 and 80K, respectively. For the sample for y=0.010, only two doublets were observed at Room Temperature (RT) and a third doublet appeared when temperature decreased to 208K. However the RT spectrum of sample y=0.057 consisted of three quadruple-split doublets. The relative intensities of these three doublets, especially for the light doped sample, corresponding to charge transfer, changed with temperature.

A mathematical memory-based model is proposed to capture the hysteresis behavior in piezoelectric actuators. It is observed that the ascending (descending) hysteresis curves are alike and converge to one point without memory saturation. Therefore, two, dominant curves are determined and expressed as continuous functions, and the other hysteresis curves are modeled using two dominant curves through nonlinear transforming of coordinate axis. In the event of memory saturation, a new converging point is used to compensate the model prediction error. The experimental study has been carried out and our proposed model prediction method is compared with PI model and the linear model. It shows that the proposed model prediction method is better than other two methods.

The performance of infrared focal plane array (IRFPA) is known to be affected by the presence of spatial fixed pattern noise (FPN) that is superimposed on the true image. Scene-based nonuniformity correction (NUC) algorithms are widely concerned since they only need the readout infrared data captured by the imaging system during its normal operation. A novel adaptive NUC algorithm is proposed using the sparse prior that when derivative filters are applied to infrared images, the filter outputs tends to be sparse. A change detection module based on results of derivative filters is introduced to avoid stationary object being learned into the background, so the ghosting artifact is eliminated effectively. The performance of the new algorithm is evaluated with both real and simulated imagery.