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It is vital to develop a quick and reliable approach for nitrobenzene in gas phase detection. In this work, the quartz crystal microbalance (QCM) platform was used to take advantage of the porphyrin-based metal-organic frameworks (MOFs) of PCN-224 as a novel sensing material for the sensitive and selective detection of nitrobenzene vapor. Besides, a quick response time of only 16 s was achieved. Meanwhile, the frequency shift in gas sensor could be proportionally quenched in correlation with the concentration of nitrobenzene vapor. Additionally, this PCN-224-based sensor demonstrated great stability to nitrobenzene vapor. This foreshadowed the huge potential of nitrobenzene detection in gas phase for practical applications in public security.

Selective chemical detection of aniline vapor from benzene, toluene, ethylbenzene, and xylene (BTEX) is still a challenge. Here, we deliberately design a hydroxyapatite (HAP) nanorods nanobiomaterial modifying on the quartz crystal microbalance transducer for highly efficient detection of aniline from aniline/BTEX mixture. Besides, at room temperature, HAP nanorods perform excellent sensitivity of aniline, and the corresponding detection limit can reach down to 5 part per billion (ppb). The stability of HAP nanorods in the sensing process is also satisfactory. The sensing mechanism, as unveiled by the theoretical basis and the enthalpy extraction experiment, is due to the moderate acid–base absorptive interaction between aniline molecule and the HAP structure. The molecular formula of hydrate C6H7N·βH2O existing in wet air (with 50–90% relative humidity) can be obtained as C6H7N·1.36∼1.93H2O based on quantitatively measurement data.

Refereed/Peer-reviewed In this paper, we argue that off-balance-sheet information is potentially useful to evaluate accounting information quality in addition to financial indicators. We propose a novel method to evaluate the accounting information quality of listed companies in China by merging four financial attributes and six indicators derived from off-balance-sheet information, where the principal component analysis is used to filter the indicators which count heavily for the evaluation. Validation and comparison are implemented on the dataset of all financial frauds and violations (5031 cases) of 1995 listed companies of Shenzhen Stock Exchange from 2003 to 2017. The results show that the proposed method outperforms both the traditional "DD model" (Dechow and Dichev, The Accounting Review 77(1):35-59, 2002) and the model only involving financial indicators in identifying and predicting financial fraud of enterprises. The results highlight that off-balance-sheet information is indeed useful and important to evaluate accounting information quality.

Three-dimensional porous carbon network (3D-C) was used as the substrate for the in situ growth of molybdenum disulfide (MoS2) through a wet chemistry method. The obtained 3D-C@MoS2 nanocomposite exhibited a porous structure, high surface area and good electrical conductivity. By using the 3D-C@MoS2 nanocomposite as a novel electrode modifier, the electrochemical oxidation peak current of bisphenol A (BPA) was greatly enhanced with a lowered background current. The improved sensitivity benefits from adsorption of BPA onto MoS2 surface, the large surface area and good conductivity of the 3D-C@MoS2 nanohybrid. By using differential pulse voltammetry (DPV), we observed a good linearity with BPA levels in the range of 0.001–10 μM, with a detection limit estimated to be 0.5 nM (S/N = 3). The 3D-C@MoS2 modified electrode could be reused for several times in spite of the accumulation of BPA, and the fabrication reproducibility is excellent. The prepared 3D-C@MoS2 modified electrode showed higher selectivity to BPA than several other phenolic compounds due to their different electrochemical oxidation potentials and the enhanced accumulation property of BPA at the 3D-C@MoS2 surface. The BPA contents in plastic product and environmental water samples were determined with the proposed method.

The laser interferometer is one of the most important key technologies for the space gravitational wave detection. A laser interferometer prototype with pico-meter measurement precision for Taiji mission in China is presented in the paper. The results showed that the path-length measurement precision reached 5 pm/√Hz within the frequency range of 10 mHz – 1 Hz by improving the temperature fluctuation noise and electronic readout noise of the laser interferometer, which meets the requirement of Taiji Pathfinder mission inside the frequency range of 1 mHz – 1 Hz under the weak-light condition. It would be a fine experimental platform for the key technologies demonstration including the laser pointing modulation and the laser phase-locking control to improve the precision for the low measurement noise.

The stability of rock slope is often controlled by the existing discontinuous surfaces, such as discrete fractures, which are ubiquitously distributing in a geological medium. In contrast with the traditional approaches used in soil slope with a continuous assumption, the simulation methods of jointed rock slope are different from that of in soil slope. This paper presents a study on jointed rock slope stability using the proposed discontinuous approach, which considers the effects of discrete fractures. Comparing with traditional methods to model fractures in an implicit way, the presented approach provides a method to simulate fractures in an explicit way, where grids between rock matrix and fractures are independent. To complete geometric components generation and mesh partition for the model, the corresponding algorithms were devised. To evaluate the stability state of rock slope quantitatively, the strength reduction method was integrated into our analysis framework. A benchmark example was used to verify the validation of the approach. A jointed rock slope, which contains natural fractures, was selected as a case study and was simulated regarding the workflow of our framework. It was set up in the light of the geological condition of the site. Slope stability was evaluated under different loading conditions with various fracture patterns. Numerical results show that fractures have significant contributions to slope stability, and different fracture patterns would lead to different shapes of the slip surface. The devised method has the ability to calculate a non-circular slip surface, which is different from a circular slip surface obtained by classical methods.

The stability of a fractured rock mass around a subsurface opening is critical to tunnel excavation. The traditional underground excavation analysis is based on a continuum description of randomly distributed discrete pre-existing fractures. In contrast to this, we have developed an improved hybrid finite element method (FEM) to investigate the stability of fractured rocks around an excavation by incorporating the outputs into the FEM codes. The proposed model consists of a discrete fracture network (DFN) model and cohesive zone model (CZM). The DFN model automatically generates a fracture network with a given fracture opening distribution and provides grid generation strategy to the FEM. The CZM captures material failure and intersection and surface contacts through the fracture element with different constitutive laws. As a case study, a DFN model was formulated for the underground excavation at Jinping Hydropower Station, in light of the input requirements of our model, and its deformation analysis was performed. The comparison analysis of rock deformation was made for excavation in both intact rock mass and fractured rock mass under the same boundary conditions. The numerical results show that two different modes of rock failure exist in these two rock masses and that intense deformation at the fractures intersected by the tunnel is responsible for fractured rock mass instability. The proposed approach was verified using data from field investigations. A larger displacement can be produced if the rock mass is weakened by a key block. A sensitivity analysis was carried out to investigate the effects of different model parameters on deformation variations. This study provides an insightful understanding of the deformation of fractured rock mass during tunnel excavation.

Optic atrophy resulting from retinal ganglion cell (RGC) degeneration is a prominent ocular manifestation of mitochondrial dysfunction. Although transgenic mice lacking the mitochondrial complex I accessory subunit NDUFS4 develop early-onset optic atrophy, severe systemic mitochondrial dysfunction leads to very early death and makes this mouse line impractical for studying the pathobiology of mitochondrial optic neuropathies. Theoretically, RGC-specific inactivation of ndufs4 would allow characterization of RGC degeneration over a longer time course, provided that RGC death from mitochondrial dysfunction is a cell-autonomous process. We demonstrate that the vesicular glutamate transporter VGLUT2 may be exploited to drive robust Cre recombinase expression in RGCs without any expression observed in directly neighboring retinal cell types. Deletion of ndufs4 in RGCs resulted in reduced expression of NDUFS4 protein within the optic nerves of Vglut2-Cre;ndufs4loxP/loxP mice. RGC degeneration in Vglut2-Cre;ndufs4loxP/loxP retinas commenced around postnatal day 45 (P45) and progressed to loss of two-thirds of RGCs by P90, confirming that intrinsic complex I dysfunction is sufficient to induce RGC death. The rapidly-developing optic atrophy makes the Vglut2-Cre;ndufs4loxP/loxP mouse line a promising preclinical model for testing therapies for currently untreatable mitochondrial optic neuropathies such as Leber Hereditary Optic Neuropathy.