Working fluids selection for fishing boats waste heat powered organic Rankine-vapor compression ice maker

To utilize waste heat from fishing boats, an organic Rankine cycle/vapor compression cycle system was employed for ice making and a thermodynamic model was developed. Six working fluids were selected and compared in order to identify suitable working fluids which may yield high system efficiencies. The calculated results show that R600a is most suitable working fluid through comprehensive comparison of efficiency, size parameter, pressure ratio, coefficient of performance, system pressure and safety.     

基于光散射的实时气溶胶粒子形状识别技术研究

利用米氏散射理论和时域有限差分(FDTD)软件计算了不同大小、形状和折射率粒子的前向散射光场分布,分析了通过光强度分布和非对称因子反演粒子相关信息、区分粒形的可行性。研制了一台利用增强型CCD相机在线采集单个气溶胶粒子在5°~19°前向散射角范围内光场图样的装置。8μm粒径的聚苯乙烯球形粒子散射图样实验结果与理论计算对比较为吻合,验证了该装置的有效性。应用该装置对不同形状的气溶胶粒子进行检测,结果表明能够从散射图像和反演计算结果区分出球形、杆状和其他形状粒子。     

Evaluating a four-directional benzene-centered aliphatic polyamine curing agent for epoxy resins

A four-directional benzene-centered aliphatic polyamine, MXBDP, with high functionality and low volatility, is used to cure epoxy resin (DGEBA). Herein we originally report the isothermal cure kinetics and dynamic mechanical properties of DGEBA/MXBDP. Differential scanning calorimetry confirms that MXDBP is more reactive than commercial linear metaxylenediamine and branched Jeffamine T-403 and the isothermal curing reaction is autocatalytic. The Kamal model is found to be able to well describe the curing rate up to the onset of diffusion control, and the excellent match over the whole conversion range is achieved using the extended Kamal model. Interestingly, the isoconversional kinetic analysis indicates that the effective reaction activation energy (E _α ) changes substantially with conversion, and ultimately decreases to a very small value (<10 kJ mol^?1) because of the diffusion-controlled reaction kinetics. Then, dynamic mechanical analysis reveals that DGEBA/MXBDP exhibits the higher α- and β-relaxation temperatures and the much higher crosslink density than DGEBA/metaxylenediamine. Our experiment results support that MXBDP has the high reactivity and improved thermal resistance in combination with the advantages of the high functionality, low volatility and decreased CO₂ absorption. Therefore, MXBDP may be especially suitable for room temperature-cure epoxy coatings and adhesives.     

Syntheses, structures and magnetic properties of three Co(II) coordination architectures based on a flexible multidentate carboxylate ligand and different N-donor ligands

Three new cobalt complexes, {[Co₅(tci)₂(bimb)₃(µ₃-O)₂(H₂O)₂]·3DMF·4H₂O} _n (1), {[Co₃(tci)₂(bib)]·2DMF·2H₂O} _n (2) and {[Co(Htci)(bpea)_0.5]·H₂O} _n (3) (H₃tci = tris(2-carboxyethyl)isocyanurate, bimb = 4,4′-bis(imidazol-1-yl)biphenyl, bib = 1,4-bis(imidazol-1-yl)benzene, bpea = 1,2-bis(4-pyridyl)ethane, DMF = N,N′-dimethylformamide), have been successfully synthesized through the assembly of Co(II) ions, H₃tci and different N-donor ligands, respectively. All complexes were structurally characterized by single crystal X-ray diffraction, elemental analyses, IR spectra, thermogravimetric (TG) analyses and X-ray powder diffraction (XRPD). Complex 1 exhibits a 3D three-fold parallel interpenetrated 3D → 3D structure with (6⁵·8) CdSO₄ topology. Complex 2 is built from [Co₃(µ₂-O_carboxyl)₂(CO₂)₄] clusters and linear bib ligands, displaying a two-fold parallel interpenetrated (3,8)-connected (4³)₂(4⁶·6¹⁸·8⁴) topology, while complex 3 is a 3D pillar-layered structure involving an infinite -Co-(µ₂-Ocarboxyl)(CO₂)-Co-chain. The diverse structures of the three complexes indicate that the skeletons of different N-donor ligands play an important role in the assembly of such different frameworks. In addition, magnetic investigation indicates that besides spin-orbit coupling of Co(II) ions, there exist antiferromagnetic exchange interactions in Co₅ and Co₃ clusters of 1 and 2, respectively.     

Chemomics and drug innovation

Chemomics is an interdisciplinary study using approaches from chemoinformatics,bioinformatics,synthetic chemistry,and other related disciplines.Biological systems make natural products from endogenous small molecules (natural product building blocks) through a sequence of enzyme catalytic reactions.For each reaction,the natural product building blocks may contribute a group of atoms to the target natural product.We describe this group of atoms as a chemoyl.A chemome is the complete set of chemoyls in an organism.Chemomics studies chemomes and the principles of natural product syntheses and evolutions.Driven by survival and reproductive demands,biological systems have developed effective protocols to synthesize natural products in order to respond to environmental changes;this results in biological and chemical diversity.In recent years,it has been realized that one of the bottlenecks in drug discovery is the lack of chemical resources for drug screening.Chemomics may solve this problem by revealing the rules governing the creation of chemical diversity in biological systems,and by developing biomimetic synthesis approaches to make quasi natural product libraries for drug screening.This treatise introduces chemomics and outlines its contents and potential applications in the fields of drug innovation.     

Ultrasound‐Assisted Construction of Halogen‐Bonded Nanosized Cocrystals That Exhibit Thermosensitive Luminescence

Multi‐component organic nanocrystals that are comprised of two or more supramolecular building blocks can be used to extend the design and assembly scope of solid molecular materials. Herein, we report the use of ultrasonication to prepare halogen‐bonded stilbene‐based nano‐cocrystals that exhibit different photoemission properties, including one‐ and two‐phonon emission and fluorescence lifetimes, relative to those of macrodimensional crystals. The structural transformation from nano‐cocrystals into nanocrystals upon heating results in a luminescence red‐shift from greenish blue to yellow. The temperature‐dependent ratiometric luminescence may allow such nano‐cocrystals to be used as fluorescent sensors and thermosensitive materials.     

Status of uncertainty assessment in k 0-NAA measurement: anything still missing?

Several approaches to quantifying measurement uncertainty in k ₀-based neutron activation analysis (k ₀-NAA) are reviewed, comprising the original approach, the spreadsheet approach, the dedicated computer program involving analytical calculations and the two k ₀-NAA programs available on the market. Two imperfectness in the dedicated programs are identified, their impact assessed and possible improvements presented for a concrete experimental situation. The status of uncertainty assessment in k ₀-NAA is discussed and steps for improvement are recommended. It is concluded that the present magnitude of measurement uncertainty should further be improved by making additional efforts in reducing uncertainties of the relevant nuclear constants used.     

Development of a solid‐phase microextraction fiber by the chemical binding of graphene oxide on a silver‐coated stainless‐steel wire with an ionic liquid as the crosslinking agent

Graphene oxide was bonded onto a silver‐coated stainless‐steel wire using an ionic liquid as the crosslinking agent by a layer‐by‐layer strategy. The novel solid‐phase microextraction fiber was characterized by scanning electron microscopy, energy‐dispersive X‐ray spectroscopy and Raman microscopy. A multilayer graphene oxide layer was closely coated onto the supporting substrate. The thickness of the coating was about 4 μm. Coupled with gas chromatography, the fiber was evaluated using five polycyclic aromatic hydrocarbons (fluorene, anthracene, fluoranthene, 1,2‐benzophenanthrene, and benzo(a)pyrene) as model analytes in direct‐immersion mode. The main conditions (extraction time, extraction temperature, ionic strength, and desorption time) were optimized by a factor‐by‐factor optimization. The as‐established method exhibited a wide linearity range (0.5–200 μg/L) and low limits of determination (0.05–0.10 μg/L). It was applied to analyze environmental water samples of rain and river water. Three kinds of the model analytes were quantified and the recoveries of samples spiked at 10 μg/L were in the range of 92.3–120 and 93.8–115%, respectively. The obtained results indicated the fiber was efficient for solid‐phase microextraction analysis.     

A sensitive immunosorbent bio-barcode assay based on real-time immuno-PCR for detecting 3,4,3',4'-tetrachlorobiphenyl

A functionalized gold-nanoparticle bio-barcode assay, based on real-time immuno-PCR (IPCR), was designed for the determination of 3,4,3',4'-tetrachlorobiphenyl (PCB77). 15 nm gold nanoparticles were synthesized, and modified with thiol-capped DNA and goat anti-rabbit IgG. The nanoparticle probes were used to replace antibody–DNA conjugate in the IPCR, and were fixed on the PCR tube wall via the immune reaction. Real-time PCR was performed to quantify the DNA signal directly. Under optimized conditions, the new method was used to detect PCB77 with a linearity range from 5 pg L^?1 to 10 ng L^?1, and the limit of detection (LOD) was 1.72 pg L^?1. Real samples of Larimichthys polyactis, collected from the East China Sea, were analyzed. Recovery was from 82 % to 112 %, and the coefficient of variation (CV) was acceptable. The results were compared with GC–ECD, revealing that the method would be acceptable for providing rapid, semi-quantitative, and reliable test results for making environmental decisions.

Redox Dyshomeostasis Strategy for Hypoxic Tumor Therapy Based on DNAzyme-Loaded Electrophilic ZIFs

Redox homeostasis is one of the main reasons for reactive oxygen species (ROS) tolerance in hypoxic tumors, limiting ROS-mediated tumor therapy. Proposed herein is a redox dyshomeostasis (RDH) strategy based on a nanoplatform, FeCysPW@ZIF-82@CAT Dz, to disrupt redox homeostasis, and its application to improve ROS-mediated hypoxic tumor therapy. Once endocytosed by tumor cells, the catalase DNAzyme (CAT Dz) loaded zeolitic imidazole framework-82 (ZIF-82@CAT Dz) shell can be degraded into Zn²⁺ as cofactors for CAT Dz mediated CAT silencing and electrophilic ligands for glutathione (GSH) depletion under hypoxia, both of which lead to intracellular RDH and H₂O₂ accumulation. These “disordered” cells show reduced resistance to ROS and are effectively killed by ferrous cysteine-phosphotungstate (FeCysPW) induced chemodynamic therapy (CDT). In vitro and in vivo data demonstrate that the pH/hypoxia/H₂O₂ triple stimuli responsive nanocomposite can efficiently kill hypoxic tumors. Overall, the RDH strategy provides a new way of thinking about ROS-mediated treatment of hypoxic tumors.