In Situ MOF-74-Pyrolysis-Generated Porous Carbon Supporting Spinel Cu0.15Co2.85O4/C Boosts Ammonium Perchlorate Accelerating Decomposition: Precise Cu Doping Modulating Oxygen Vacancy Concentration.

As one of the main components of solid propellant, ammonium perchlorate (AP) shows slow sluggish decomposition kinetics with unconcentrated heat release. To achieve efficient catalytical decomposition, it is a significant challenge to design reasonable catalyst structure and explore the interaction between catalyst and AP. Herein, a series of porous carbon supported spinel-typed homogeneous heterometallic composites CuxCo3-xO4/C via pyrolysis of MOF-74-Co doped Cu. On basis of precise electronic-structure-tuning through modulating Cu/Co ratio in MOF-74, Cu0.15Co2.85O4/C with 5% Cu-doping featuring oxygen vacancy concentration of 26.25% exhibits the decrease to 261.5 °C with heat release up to 1222.1 J g-1 (456.9 °C and 669.2 J g-1 for pure AP). The detail process of AP accelerated decomposition is approved by TG-DSC-FTIR-MS technique. Density functional theory calculation revealed that in the Cu0.15Co2.85O4/C, the distinctive ability for NH3 catalyzed oxidation assisted with absorption performance of active porous C boosts accelerating AP decomposition. The findings would provide an insight for perceiving and understanding AP catalytic decomposition.

Influence of lattice water molecules on the magnetization dynamics of binuclear dysprosium(III) compounds: insights from magnetic and ab initio calculations.

Lattice water effects on the structures and magnetic properties of single-molecule magnets (SMMs) have attracted considerable attention. Herein, we have successfully synthesized two centrosymmetric binuclear compounds [Dy2(2,3'-ppcad)2(C2H3O2)4(H2O)2] (1) and [Dy2(2,3'-ppcad)2(C2H3O2)4(H2O)2]·6H2O (2) (2,3'-Hppcad = N3-(2-pyrazinyl)-3-pyridinecarboxamidrazone) by elaborately varying the amount of the base (LiOH·H2O). Through isothermal titration calorimetry (ITC), the interactions between DyIII ions and 2,3'-Hppcad with different amounts of LiOH·H2O were monitored in real time. Magnetic studies reveal that two compounds exhibit the typical zero-field single-molecule magnet behavior with different energy barrier (Ueff) values of 103.43 K for 1 and 386.48 K for 2, wherein the SMM performance for 2 stands out among the reported nine-coordinated Dy2-SMMs systems with spherical capped square antiprism (C4v) geometries. To rationalize the observed difference in the magnetic properties of 1 and 2, ab initio calculations have been performed. The introduction of lattice water molecules leads to differences in the J values observed for 1 and 2. The stronger antiferromagnetic DyIII-DyIII couplings in 2 were presented and the fast quantum tunneling of magnetization was further suppressed, thereby achieving a higher Ueff value. This work provides an effective strategy to enhance the SMM performance, and combines with ab initio calculations to explain how lattice water molecules can affect the magnetic interactions of Dy2-SMMs.

Biomimetic Total Synthesis of the Spiroindimicin Family of Natural Products.

A unified strategy for the biomimetic total synthesis of the spiroindimicin family of natural products was reported. Key transformations include a one-pot two-enzyme-catalyzed oxidative dimerization of L-tryptophan/5-chloro-L-tryptophan to afford the bis-indole precursors chromopyrrolic acid/5',5''-dichloro-chromopyrrolic acid, and regioselective C3'-C2'' and C3'-C4'' bond formation converting a common bis-indole skeleton to two skeletally different natural products, including (±)-spiroindimicins D and G with a [5,5] spiro-ring skeleton, and (±)-spiroindimicins A and H with a [5,6] spiro-ring skeleton, respectively.

[Study on Si-PIN and CdTe Detectors Used in Energy Dispersive X-Ray Fluorescence Measurements].

Semiconductor detector is widely used in energy dispersive X-ray fluorescence measurements due to its excellent performance. In this paper, Si-PIN and CdTe semiconductor detectors were studied, performances of the two detectors were compared in material properties, detection efficiency, energy resolution and other aspects. Focused on the performance of the detectors influenced by the thickness of detector sensitive area, energy of incident X-ray, shaping time of post-stage circuit, and analyzed the differences of energy spectrum caused by escape peaks and hole trailing. Aiming at the problem of incomplete hole collection in detector, a digital multi-channel analyzer (DMCA) based on FPGA with rise-time discriminator was designed, it could reduce the influence of hole trailing effectively and improve energy resolution. The experimentation results indicate that the detection efficiency of Si-PIN and CdTe is roughly equal when energy is below 15 keV while CdTe has much higher detection efficiency than Si-PIN when energy is above 15 keV. The optimum forming time of the Si-PIN detector is about 10 µs, and the CdTe detector is about 2.6 µs, so the CdTe detector is more suitable for the high count rate condition. Si-PIN detector has better energy resolution than CdTe detector for different energy incident X-ray. CdTe detector has obvious hole tailing effect and the energy resolution of CdTe detector is significantly improved by using DMCA with rise-time discrimination.

Deep-learning-based cross-modality translation from Stokes image to bright-field contrast.

Significance: Mueller matrix (MM) microscopy has proven to be a powerful tool for probing microstructural characteristics of biological samples down to subwavelength scale. However, in clinical practice, doctors usually rely on bright-field microscopy images of stained tissue slides to identify characteristic features of specific diseases and make accurate diagnosis. Cross-modality translation based on polarization imaging helps to improve the efficiency and stability in analyzing sample properties from different modalities for pathologists. Aim: In this work, we propose a computational image translation technique based on deep learning to enable bright-field microscopy contrast using snapshot Stokes images of stained pathological tissue slides. Taking Stokes images as input instead of MM images allows the translated bright-field images to be unaffected by variations of light source and samples. Approach: We adopted CycleGAN as the translation model to avoid requirements on co-registered image pairs in the training. This method can generate images that are equivalent to the bright-field images with different staining styles on the same region. Results: Pathological slices of liver and breast tissues with hematoxylin and eosin staining and lung tissues with two types of immunohistochemistry staining, i.e., thyroid transcription factor-1 and Ki-67, were used to demonstrate the effectiveness of our method. The output results were evaluated by four image quality assessment methods. Conclusions: By comparing the cross-modality translation performance with MM images, we found that the Stokes images, with the advantages of faster acquisition and independence from light intensity and image registration, can be well translated to bright-field images.

Polycyclic aromatic hydrocarbons with molecular weight 302 in PM 2.5 at two industrial sites in South China.

Daytime and nighttime PM(2.5) samples were collected between August 5 and 16, 2009 and between January 24 and February 4, 2010 in an industrial complex site (site A) and an electronic waste recycling site (site B) to determine the seasonal and diurnal variations of 19 individual polycyclic aromatic hydrocarbons (PAHs) with molecular weight 302 (MW302) including four highly carcinogenic dibenzopyrene (DBP) isomers dibenzo[a,l]pyrene (DBalP), dibenzo[a,e]pyrene (DBaeP), dibenzo[a,i]pyrene (DBaiP), and dibenzo[a,h]pyrene (DBahP). This is the first report on DBP isomers in air particles from South China. The total concentration of PAH MW302 isomers ranged from 1.65 to 3.60 ng m(-3) in summer and 3.82 to 9.81 ng m(-3) in winter. The strongest peaks in the chromatograms of the MW302 isomers were naphtha[2,1-a]pyrene (N21aP), dibenzo[j,l]fluoranthene (DBjlF), naphtha[1,2-b]fluoranthene (N12bF), naphtha[1,2-k]fluoranthene (N12kF) and dibenzo[a,e]fluoranthene (DBaeF), constituting 52.0 to 55.4% of the total MW302 isomers. All the MW302 isomers showed notable seasonal variations. Most of the MW302 isomers in site B showed distinctive diurnal variations with higher concentrations occurring in the night. Taking into account both concentration and potency equivalence factors (PEFs), the strongest carcinogen in the analyzed samples was DBaiP, and the ratios of sum carcinogenic potency of four highly carcinogenic DBP isomers to benzo[a]pyrene (BaP) was about 0.94 in winter to 1.89 in summer, indicating the importance of DBP isomers for the risk assessment. Health risk assessment indicated that on average, 1 in 100 000 residents in the two industrial sites may have an increased risk of cancer due to PAH exposure.

Improving the Environmental Footprint through Employees: A Case of Female Leaders from the Perspective of CSR.

Environmental quality strongly depends on human behavior patterns. Many environmental challenges are rooted in human actions, and thus, it is believed that these problems can be reduced through the promotion of pro-environmental behaviors (PB). Owing to this reality, the current study aims to reduce the environmental footprint of a hospital by promoting its employees' environment-specific behavior via corporate social responsibility (CSR) and ethical leadership (EL). More importantly, the study also considered the role of female leaders in the proposed relationship. The current study collected the data from the respondents employed in different hospitals of a developing economy through a questionnaire (paper-pencil method). A total of 489 valid responses were collected, which were analyzed by employing the structural equation modeling (SEM) technique. As per the current study's findings, there is a positive relationship between CSR, while EL mediates between CSR and PB. Likewise, the moderating role of female leaders in the proposed relationship was more significant than that of male leaders. More specifically, the study's findings have considerable theoretical and practical implications, as it opens paths for researchers to further investigate the applicability of different dimensions of CSR and the role of gender in environmental sustainability. It provides insight to policymakers on how to restructure their CSR preferences, priorities on the environment, and gender differences.

An Examination to Explain the Mechanism of Employees' Environment-Specific Behavior through CSR and Work Engagement from the Perspective of Stewardship Theory.

Corporate social responsibility (CSR) has emerged as an imperative for every sector globally. Yet, for a long time, the concept of CSR has been regarded from an organizational perspective. However, the importance of CSR in shaping the extra-role behavior of employees, such as their pro-environmental behavior (PEB-E), has been under-explored in the literature. Against this backdrop, the current study aims to investigate the impact of CSR on PEB-E with the mediating effect of work engagement (W.E) in the context of a emerging country. The study also employs stewardship theory as an alternate theory to explain the proposed relationships. The data of the current study were obtained from SME sector through a self-administered (paper-and-pencil method) questionnaire. A random sample of employees (n = 398) from different SMEs was selected and analyzed through structural equation modeling. The results of the current survey revealed that CSR directly and indirectly, via W.E, predicts PEB-E positively. The findings of the current study will be helpful for policymakers to understand that well-planned CSR activities, not only create positive repute for an SME, but also provide the underlying justification to its employees to be engaged in different environment-specific behaviors.

Research and development of a high-performance differential-hybrid charge sensitive preamplifier.

A differential-hybrid charge sensitive preamplifier (CSP) was designed by taking a monolithic dual N-Channel Junction Field-effect Transistor (JFET) and a high-speed, low-noise, operational amplifier as the core parts. Input-stage of the circuit employs low-noise differential dual JFET, which ensures high input impedance and low noise. The differential dual transistor makes the quiescent point of the first-stage differential output stable, which is convenient for connecting with the post stage high-speed operational amplifier. Broadband could be amplified by connecting to the double differential dual transistors through the folded cascode-bootstrap. The amplifying circuit which replaces the interstage and post stage discrete components of a traditional CSP with integrated operational amplifier is simpler and more reliable. It simplifies the design of the quiescent point, gives full play to advantages of releasing large open-loop gain, and improves charge-voltage conversion gain stability. Particularly, the charge-voltage conversion gain is larger under a smaller feedback capacitor, thus enabling to gain better signal-noise ratio. The designed CSP was tested, reporting 3.3×1013 V/C charge sensitivity, about 90ns rise time of signals, 35:1 signal-noise ratio to gamma-rays of 137Cs (662keV) and a 0.023 fC/pF noise slope. Gamma-rays of 241Am (59.5keV) were measured by the BPX66 detector and the designed CSP under room temperature, providing 1.97% energy resolution.