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The microstructure of long flame coal samples subjected to different high temperature steam was studied by means of micro CT technique. The results show that when the pyrolysis temperature is lower than 300 ℃, the loss of free water and gas leads to the formation of cracks. When the pyrolysis temperature is higher than 300 ℃, the interconnecting crack network is formed in the pyrolysis of organic matter, and the pores and cracks are mainly formed in the organic matter. Pyrolysis can be divided into three stages. Before 300 ℃, coal samples are pyrolyzed slowly, and pores and cracks increase slowly. The pyrolysis intensifies between 300 ℃ and 500 ℃, and the porosity of coal samples increases obviously. When the pyrolysis temperature is higher than 500 ℃, the pyrolysis is the most complete and the porosity of coal samples increases sharply. After 550 ℃, the volume porosity of the coal sample reaches 32.35%, which is 9.82 times higher than that at 25 ℃. Moreover, 300 ℃ is the threshold point of pyrolysis. When the pyrolysis temperature is higher than the threshold point, different bedding planes are well developed, forming a pore network through each other, accelerating pyrolysis and providing a migration channel for pyrolysis products.

The coalification process significantly influences the composition of coal material and the development of pore size, ultimately affecting the adsorption capacity of coal seams and the extraction of coalbed methane. This project aimed to assess the pore structure and gas adsorption capacity of coal samples from nine key sedimentary basins in China. The N 2 test results revealed that during the initial stage of coalification, micropore, transition pore, and mesopore dominate in order of magnitude. In the subsequent coalification stages, the development of mesopore is most significant during the second jump, while the transition pore becomes more prominent in the third jump. Additionally, the findings from nuclear magnetic resonance tests indicate that the proportion of adsorbed pore demonstrates a decreasing-then-increasing trend throughout the coalification process. The first and second coalification jumps primarily contribute to the development of adsorption pore and seepage pore, whereas the third jump mainly focuses on adsorption pore development. The gas adsorption capacity is influenced by various factors such as pore structure, material composition, and chemical structure. During the first coalification jump, gas adsorption mainly occurs in the adsorption pore. In the second jump, medium gas adsorption capacity is achieved due to the combined effects of enhanced adsorption pore development and reduced moisture and ash content. Finally, the third coalification jump exhibits highly developed adsorption pores, the lowest moisture and ash levels, and a sufficient aromatic structure in the chemical composition, resulting in high adsorption capacity. These findings contribute to a deeper understanding of the variations in coalbed methane enrichment across different basins in China, with coalification playing a crucial controlling role. • Three key stages in coal pore evolution identified. • Pore size distribution during coal thermal evolution in key basins studied. • Gas adsorption capacity of coal during coalification jumps studied. [ABSTRACT FROM AUTHOR]

Configurational entropy manipulation strategy has been proposed for designing high-performance thermoelectric materials. Understanding the phase stability is essential to regulate the thermal conductivity for optimizing the thermoelectric performance. Herein, the lattice thermal conductivity of PbSe is found to decrease from 1.87 to 0.76 Wm−1 K−1 of PbSe 0.5 Te 0.25 S 0.25 , which mainly results from the decreased contribution from the phonon modes in the frequency range of 0.5–2 THz. Moreover, we find local chemical ordering (LCO) in PbSe 0.5 Te 0.25 S 0.25 by conducting hybrid Monte Carlo and molecular dynamics simulations based on our constructed machine-learning interatomic potential. The local chemical ordering can reduce phonon scattering with frequency in 0–2 THz, thus enhancing thermal conductivity by approximately 14%. This work unfolds the energy favorable structure with LCO in entropy-tailored thermoelectric material, which gives guidance for regulating thermal transport. [ABSTRACT FROM AUTHOR]

This paper studies the prediction based on a composite target function that allows to simultaneously predict the actual and the mean values of the unobserved regressand in the generalized linear model. The best linear unbiased prediction (BLUP) of the target function is derived. Studies show that our BLUP has better properties than some other predictions. Simulations confirm its better finite sample performance.

As one of the main interfaces of the Earth system, estuaries show the strongest land–sea interaction in the carbon cycle, which links terrestrial ecosystems to the marginal sea. Furthermore, estuaries are considered as one of the most active intermediate reservoirs for both terrestrial and marine matter due to complex hydrodynamic processes regulated by the river runoff, wave and tide. Processing of organic matter (OM) in tidal estuaries modifies its transfer and transformation from the river to the sea, so studies of on the source and distributions of estuarine OM can help us understand the behavior of production, exchange, transport and burial of diverse OM within this transition zone before entering the marginal sea. In this paper, we took the Minjiang River Estuary (MRE) as a typical system in which there is strong influence of the tide. The source, composition and spatial distribution of OM in surface sediments of MRE were deciphered based on multiple organic geochemical properties for source-specific biomarkers (n-alkanes, n-alkanols, sterols) and bulk OM. Results show that sedimentary organic components were negatively correlated with sediment grain size, which indicates fine particles such as silt and clay are the major carriers of the OM signals in tidal estuaries. Source-specific biomarker proxies indicate that in terms of source diversity the sedimentary OM in the MRE shows mixed signals of terrestrial and marine sources, and the proportion of terrestrial OM decreases with the increase in distance from the land. The fractional contributions of OM from the riverine (i.e., terrestrial), marine and deltaic sources were quantitatively estimated using a Monte Carlo (MC) three-end-member mixing model based on C/N and δ13C values, and the average contributions of the three sources are 40 ± 10%, 48 ± 10% and 12 ± 4%, respectively, with little contribution from deltaic sources. The dispersion of sedimentary OM from different sources in the MRE is primarily controlled by the depositional environment determined by dynamic conditions and tidal processes play a significant role in the redistribution of sedimentary OM dispersion patterns. Compared with other large estuaries in southeast China, the OM accumulation contribution in the tide dominated small and medium-sized estuaries such as the MRE which is largely dependent on riverine and marine deliveries. The MRE has a high potential for both terrestrial and marine organic carbon (OC) burial, with an accumulation rate of 3.39 ± 1.83 mg cm−2 yr−1 for terrestrial OC, and an accumulation rate of 3.18 ± 0.68 mg cm−2 yr−1 for marine OC in muddy sediment, making it an important contributor to the sedimentary carbon sink of the marginal sea. [ABSTRACT FROM AUTHOR]

This paper reports a Fabry−Pérot (F–P) cavity constructed by metal–organic frameworks (MOFs) encapsulated with TiO2 nanoparticles that can achieve selective sensing of chemicals. The MOFs‐based F–P cavity is fabricated by sequentially spray‐coating TiO2 in HKUST‐1 thin films through a layer‐by‐layer deposition strategy. The bandwidth of the cavity is tuned over a broad range by adjusting the thickness and refractive index of the HKUST‐1⊃TiO2 thin films with controllable TiO2 size and concentration. Selective sensing of chemical vapors is demonstrated on the HKUST‐1⊃TiO2 cavities which are attributed to enhanced interaction between hydroxyl groups on the surface of TiO2 and the specific oxygen‐containing analytes. In addition, molecule dynamics simulation and infrared absorption spectrum characterization are conducted to elucidate the mechanism of enhanced sensing properties. Homogeneous encapsulation of functional guest pieces with smaller sizes in MOF films contributes to specific physical–chemical properties that benefit their device applications in optical communication and chemical sensing. [ABSTRACT FROM AUTHOR]

This study investigated the effects of hyperoside pre-treatment on the oxidative stress, inflammatory response and apoptosis in rats with cerebral ischemia-reperfusion (I/R) injury. SD rats were randomly divided into sham, I/R, hyperoside (I/R + Hyp) and nimodipine (I/R + Nim) groups. The rats in the hyperoside group and the nimodipine group were intra-gastrically given hyperoside (50 mg/kg/day) and nimodipine (15 mg/kg/day), respectively, 15 days before operation. A rat cerebral ischemia model was established by suture-occlusion 1 h after the last administration. The thread embolus was removed 2 h after the ischemia for the 24 h reperfusion. The results showed that compared with that in the I/R model group, the neurologic function of the hyperoside group rats was significantly improved and the cerebral infarction volume ratio decreased significantly. The total antioxidant capacity, the activity of superoxide dismutase and glutathione peroxidase in the brain tissue of the hyperoside group rats were significantly higher than those in the I/R model group. The content of malondialdehyde, interleukin-1β and tumour necrosis factor-α in the brain tissue of the hyperoside group rats was significantly lower than that in the I/R model group. Compared with that in the I/R model group, the expression of Bcl-2 mRNA, and p-PI3K and p-AKT proteins in the hyperoside group increased significantly, whereas that of Bax and caspase-3 mRNA decreased significantly. These results suggest that hyperoside had a significant protective effect against cerebral I/R injury in rats, which is related to its inhibiting the oxidative stress, alleviating the inflammatory response and having anti-apoptotic effects. [ABSTRACT FROM AUTHOR]

Exosomes can pass through the blood-brain barrier and are present in the cerebrospinal fluid (CSF). The components in exosomes, such as DNA, RNA, protein, and lipids, change greatly and are closely related to disease progression. Circular RNA (circRNA) is stable in structure and has a long half-life in exosomes without degradation. Therefore, circRNA is considered an ideal biomarker and can be used to monitor a variety of central nervous system diseases. This study aimed to investigate the expression profiles of exosomal circRNA (exo-circRNA) in CSF from patients with immune-mediated demyelinating diseases to identify suitable biomarkers for the early diagnosis of immune-mediated demyelinating diseases. circRNA expression levels in exosomes obtained from five CSF samples from immune-mediated demyelinating disease patients and five paired CSF control samples were analyzed using a hybridization array. Hierarchical clustering analysis showed that 5,095 exo-circRNAs were differentially expressed between patients with immune-mediated demyelinating diseases and paired control samples. Of these exo-circRNAs, 26 were identified as significantly differentially expressed in CSF exosomes from patients with immune-mediated demyelinating diseases (FC ≥1.5 and p ≤ 0.05). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis indicated that the upregulation or activation of protein tyrosine phosphatase receptor type F (PTPRF) and RAD23 homolog B, nucleotide excision repair protein (RAD23B) may be associated with the occurrence and development of immune-mediated demyelinating diseases. Then, a competing endogenous RNA network was constructed and centered on the most upregulated/downregulated exo-circRNAs to predict their function in immune-mediated demyelinating diseases. In addition, reverse transcription quantitative polymerase chain reaction results stating that hsa_circ_0087862 and hsa_circ_0012077 were validated in an independent cohort of subjects. Canonical correlation analysis results indicated a potential connection between exosomal hsa_circ_0012077 expression level and immunoglobulin G levels in CSF. Finally, the receiver operating characteristic (ROC) curve showed that when hsa_circ_0087862 or hsa_circ_0012077 was employed alone for diagnosing immune-mediated demyelinating diseases, the diagnostic accuracy was 100%. In conclusion, based on this study, exosomal hsa_circ_0087862 and hsa_circ_0012077 in CSF could be used as suitable biomarkers for the diagnosis of immune-mediated demyelinating disease based on their expression levels. Moreover, the upregulation or activation of PTPRF and RAD23B was potentially associated with the occurrence and development of immune-mediated demyelinating diseases. [ABSTRACT FROM AUTHOR]

The present study explored the role of endothelin-1, H2S, and Nrf2 in remote preconditioning (RIPC)-induced beneficial effects in ischemia–reperfusion (I/R)-induced vascular dementia. Mice were subjected to 20 min of global ischemia by occluding both carotid arteries to develop vascular dementia, which was assessed using Morris water maze test on 7th day. RIPC was given by subjecting hind limb to four cycles of ischemia (5 min) and reperfusion (5 min) and it significantly restored I/R-induced locomotor impairment, neurological severity score, cerebral infarction, apoptosis markers along with deficits in learning and memory. Biochemically, there was increase in the plasma levels of endothelin-1 along with increase in the brain levels of H2S and its biosynthetic enzymes viz., cystathionine-β-synthase (CBS) and cystathionine-γ-lyase (CLS). There was also an increase in the expression of Nrf2 and glutathione reductase in the brain in response to RIPC. Pretreatment with bosentan (dual blocker of ETA and ETB receptors), amino-oxyacetic acid (CBS synthase inhibitor), and DL-propargylglycine (CLS inhibitor) significantly attenuated RIPC-mediated beneficial effects and biochemical alterations. The effects of bosentan on behavioral and biochemical parameters were more significant than individual treatments with CBS or CLS inhibitors. Moreover, CBS and CLS inhibitors did not alter the endothelin-1 levels possibly suggesting that endothelin-1 may act as upstream mediator of H2S. It is concluded that RIPC may stimulate the release endothelin-1, which may activate CBS and CLS to increase the levels of H2S and latter may increase the expression of Nrf2 to decrease oxidative stress and prevent vascular dementia. [ABSTRACT FROM AUTHOR]

Multiple loops have been used extensively to enhance the system performance in various applications. However, the increasing complexity of multi-loop systems also makes them much more difficult to analyze and implement. In this paper, a new methodology to analyze multi-loop system is proposed. In the proposed framework, multi-loop systems are regarded to be built upon of sub-modules of cascade, parallel adding, and feedback units, and then, they are simplified following a certain procedure based on the correlation of the Bode characteristics of the segmented sub-modules. Applying this methodology, the Bode plot and the transfer function of the system can be easily obtained with the system properties of gains, zeros, and poles. Two examples are provided as demonstrators, including a multi-loop low-dropout regulator (LDO) from literature, and a newly designed multi-loop LDO aiming at enhancing the stability over a wide load range, which show that the Bode plot and the transfer function can be obtained more intuitively and rapidly. Excellent agreements among theory, simulations, and measurements are confirmed, which verify the proposed method. It can help designers to gain more intuitions and insights on multi-loop systems from both circuit and device perspectives, which is also an effective tool for both stability analysis and circuit design. [ABSTRACT FROM AUTHOR]

We develop several new time‐varying coefficient regression models to investigate herding behavior in Chinese stock markets. We find evidence that herding behavior occurs during turbulent periods rather than periods of relative tranquility, which does not appear when using a conventional fixed‐coefficient regression model. Moreover, the US return dispersion had a significant influence on Chinese stock markets before 2015 but not in 2015. Finally, the herding shows significant asymmetry. [ABSTRACT FROM AUTHOR]

The nonlinear unit root test of Kapetanios, Shin, and Snell (2003) (KSS) has attracted much recent attention. However, the KSS test relies on the ordinary least squares (OLS) estimator, which is not robust to a heavy-tailed distribution and, in practice, the test suffers from a large power loss. This study develops three kinds of quantile nonlinear unit root tests: the quantile t-ratio test; the quantile Kolmogorov-Smirnov test; and the quantile Cramer-von Mises test. A Monte Carlo simulation shows that these tests have significantly better power when an innovation follows a non-normal distribution. In addition, the quantile t-ratio test can reveal the heterogeneity of the asymmetric dynamics in a time series. In our empirical studies, we investigate the unit root properties of U.S. macroeconomic time series and the real effective exchange rates for 61 countries. The results show that our proposed tests reject the unit roots more often, indicating that the series are likely to be asymmetric nonlinear reverting processes. [ABSTRACT FROM AUTHOR]

Cadmium zinc telluride detectors are the highly considered for room-temperature hard X-ray and gamma-ray detection. The readout systems are needed in the detectors to output the detecting data. The features of power supplies are very important for the readout circuits. In this paper, a low-dropout (LDO) regulator with very low power consumption and wide load variation is presented. A combining compensation method which includes partially controlled load-tracking technique and equivalent series resistance compensation technique are proposed to enhance the loop stability of the LDO regulator. Meanwhile, high dc gain is obtained to improve the power supply ripple rejection (PSRR), which can decrease the noise from the power supply. The prototype LDO chip has been fabricated and tested with a standard 0.18- \mu \textm CMOS technology. The measured results show that the LDO regulator can provide up to 150 mA load current with a stable output voltage of 2.8 V under an input voltage scope from 2.9 to 3.6 V. The measured PSRR is up to −60 dB. The output noise spectral densities are 1.16 \mu \textV\mathrm {RMS}/\sqrt {\mathrm {Hz}} and 211 nVRMS/s \sqrt \mathrm Hz at 1 and 100 kHz, respectively, at load current of 150 mA. Especially, the ultralow quiescent currents of 5.2~\mu \textA at no load and 18.2~\mu \textA at full load bring great benefit to the ultralow power integrated readout systems. [ABSTRACT FROM AUTHOR]

Many studies have estimated the optimal time-varying hedge ratio using futures, with most employing a bivariate generalized autoregressive conditional heteroscedasticity (BGARCH) model or a random coefficient model to estimate the time-varying hedge ratio. However, it has been argued that when the variability of the estimated time-varying hedge ratio is large, this ratio's hedging performance is not as good as that of the unconditional (constant) hedge ratio. This study proposes a nonparametric estimation approach to estimate and evaluate the optimal conditional hedge ratio. This method produces a time-varying hedge ratio with less volatility than those obtained from the BGARCH and random coefficient models. We evaluate the hedging performance of the various models using soybean oil, corn, S&P 500, and Hang Seng futures indices. The empirical results support the proposed nonparametric approach in terms of both in-sample and out-of-sample performance. © 2015 Wiley Periodicals, Inc. Jrl Fut Mark 36:968-991, 2016 [ABSTRACT FROM AUTHOR]

This article studies the real interest rate parity (RIP) for several Asian countries. This is done by examining the stationarity in the real interest rate differentials (rids) with respect to the US using the quantile unit root test. Our results show that rids exhibits unit-root behaviours in the lower quantile levels, and mean reversion in the upper quantile levels. Furthermore, large positive shocks tend to induce strong mean reversion and the adjustment towards the long-run equilibrium level is faster as rids gets larger, with shorter half-lives in the extreme quantile levels. [ABSTRACT FROM AUTHOR]