Energy- and exergy-based working fluid selection and performance analysis of a high-temperature PEMFC-based micro combined cooling heating and power system

A combined cooling heating and power (CCHP) system based on high-temperature proton exchange membrane fuel cell (PEMFC) is proposed. This CCHP system consists of a PEMFC subsystem, an organic Rankine cycle (ORC) subsystem and a vapor compression cycle (VCC) subsystem. The electric power of the CCHP system is 8 kW under normal operating conditions, the domestic hot water power is approximately 18 kW, and the cooling and heating capacities are 12.5 kW and 20 kW, respectively. Energy and exergy performance of the CCHP system are thoroughly analyzed for six organic working fluids using Matlab coupled with REFPROP. R601 is chosen as the working fluid for ORC subsystem based on energy and exergy analysis. The results show that the average coefficient of performance (COP) of the CCHP system is 1.19 in summer and 1.42 in winter, and the average exergy efficiencies are 46% and 47% under normal operating conditions. It can also be concluded that both the current density and operating temperature have significant effects on the energy performance of the CCHP system, while only the current density affects the exergy performance noticeably. The ambient temperature can affect both the energy and exergy performance of the CCHP system. This system has the advantages of high facility availability, high efficiency, high stability, low noise and low emission; it has a good prospect for residential applications

Visualization 1: Numerical studies of focal modulation microscopy in high-NA system

Total illumination pattern and X, Y, Z polarized components, as a function of time in z=0 plane. Originally published in Optics Express on 22 August 2016 (oe-24-17-19138

Gender-specific differences in gene expression profiles in gynogenetic Pengze crucian carp

Gynogenesis is a form of asexual reproduction that is used to obtain all-female fish stocks. In this study, we were interested in studying gender-specific differences in gene expression profiles in gynogenetic teleosts, using a carp species. The four-month old gynogenetic Pengze crucian carp F1 (<i>Carassius auratus </i>var. <i>pengzensis</i>, Pcc) showed a high ratio of males under laboratory culture condition. The present study aimed to investigate the differences between males and females. The gonadosomatic index of the females was significantly higher than that of the males. Moreover, the hepatosomatic index of the females was significantly lower than that of the males. Vitellogenin B mRNA was abnormally highly expressed in male hepatopancreas and testes compared to females. Similarly, zona pellucida 2 expressed at a significantly high level in the testes. For the sex related genes, dosage-sensitive sex reversal, adrenal hypoplasia congenital critical region on the X-chromosome gene 1, doublesex and mab-3 related transcription factor 1a, nuclear receptor subfamily 5, group A, member 1b and SRYbox containing gene 9a had significantly higher expression levels in the males than in the females, whereas there was no difference in expression of anti-Müllerian hormone, cytochrome P450 family 19 subfamily A member 1A and forkhead box L2 transcripts between the two genders. The females showed higher levels of estrogen but no significant difference in testosterone compared to the males. The data suggest remarkable differences between the two genders of the Pengze crucian carp

Molecular Scaffolding Strategy with Synergistic Active Centers To Facilitate Electrocatalytic CO₂ Reduction to Hydrocarbon/Alcohol

A major impediment to the electrocatalytic CO₂ reduction reaction (CRR) is the lack of electrocatalysts with both high efficiency and good selectivity toward liquid fuels or other valuable chemicals. Effective strategies for the design of electrocatalysts are yet to be discovered to substitute the conventional trial-and-error approach. This work shows that a combination of density functional theory (DFT) computation and experimental validation of molecular scaffolding to coordinate the metal active centers presents a new molecular-level strategy for the development of electrocatalysts with high CRR selectivity toward hydrocarbon/alcohol. Taking the most widely investigated Cu as a probe, our study reveals that the use of graphitic carbon nitride (g-C₃N₄) as a molecular scaffold allows for an appropriate modification of the electronic structure of Cu in the resultant Cu–C₃N₄ complex. As a result, the adsorption behavior of some key reaction intermediates can be optimized on the Cu–C₃N₄ surface, which greatly benefits the activation of CO₂ and leads to a more facile CO₂ reduction to desired products as compared with those on the Cu(111) surface and other kinds of Cu complexes formed on nitrogen-doped carbons. Remarkably, different from the most studied elementary metal surfaces, an intramolecular synergistic catalysis with dual active centers was for the first time observed on the Cu–C₃N₄ complex model, which possesses a unique capability to generate C₂ products. A good agreement between electrochemical measurements and the DFT analysis of the CRR has been achieved on the basis of the newly designed and synthesized Cu–C₃N₄ electrocatalyst

Strain Effect in Bimetallic Electrocatalysts in the Hydrogen Evolution Reaction

Unravelling the electrocatalytic activity origins of bimetallic nanomaterials is of great importance, yet fundamentally challenging. One of the main reasons for this is that the interactive contributions from geometric and electronic effects to enhancements in reaction activity are difficult to distinguish from one another. Here, on well-defined Ru–Pt core–shell (Ru@Pt) and homogeneous alloy (RuPt) model electrocatalysts, we are able to isolate these two effects. Furthermore, we observe the dominant role of strain in the intrinsic activity of the alkaline hydrogen evolution reaction. In the Ru@Pt icosahedral nanostructure, the highly strained Pt shells effectively accommodate the interfacial lattice mismatch from a face-centered cubic structured Ru core. This unique property leads to a weak binding of hydrogen and optimal interaction with hydroxyl species during the reaction, thus leading to an enhanced apparent activity of Ru@Pt

High Electrocatalytic Hydrogen Evolution Activity of an Anomalous Ruthenium Catalyst

Hydrogen evolution reaction (HER) is a critical process due to its fundamental role in electrocatalysis. Practically, the development of high-performance electrocatalysts for HER in alkaline media is of great importance for the conversion of renewable energy to hydrogen fuel via photoelectrochemical water splitting. However, both mechanistic exploration and materials development for HER under alkaline conditions are very limited. Precious Pt metal, which still serves as the state-of-the-art catalyst for HER, is unable to guarantee a sustainable hydrogen supply. Here we report an anomalously structured Ru catalyst that shows 2.5 times higher hydrogen generation rate than Pt and is among the most active HER electrocatalysts yet reported in alkaline solutions. The identification of new face-centered cubic crystallographic structure of Ru nanoparticles was investigated by high-resolution transmission electron microscopy imaging, and its formation mechanism was revealed by spectroscopic characterization and theoretical analysis. For the first time, it is found that the Ru nanocatalyst showed a pronounced effect of the crystal structure on the electrocatalytic activity tested under different conditions. The combination of electrochemical reaction rate measurements and density functional theory computation shows that the high activity of anomalous Ru catalyst in alkaline solution originates from its suitable adsorption energies to some key reaction intermediates and reaction kinetics in the HER process

Identification of odorant binding proteins and chemosensory proteins in <i>Microplitis mediator</i> as well as functional characterization of chemosensory protein 3

<div><p>Odorant binding proteins (OBPs) and chemosensory proteins (CSPs) play important roles in transporting semiochemicals through the sensillar lymph to olfactory receptors in insect antennae. In the present study, twenty OBPs and three CSPs were identified from the antennal transcriptome of <i>Microplitis mediator</i>. Ten OBPs (<i>MmedOBP11–20</i>) and two CSPs (<i>MmedCSP2–3</i>) were newly identified. The expression patterns of these new genes in olfactory and non-olfactory tissues were investigated by real-time quantitative PCR (qPCR) measurement. The results indicated that <i>MmedOBP14</i>, <i>MmedOBP18</i>, <i>MmedCSP2</i> and <i>MmedCSP3</i> were primarily expressed in antennae suggesting potential olfactory roles in <i>M</i>. <i>mediator</i>. However, other genes including <i>MmedOBP11</i>–<i>13</i>, <i>15–17</i>, <i>19</i>–<i>20</i> appeared to be expressed at higher levels in body parts than in antennae. Focusing on the functional characterization of MmedCSP3, immunocytochemistry and fluorescent competitive binding assays were conducted indoors. It was found that MmedCSP3 was specifically located in the sensillum lymph of olfactory sensilla basiconca type 2. The recombinant MmedCSP3 could bind several types of host insects odors and plant volatiles. Interestingly, three sex pheromone components of Noctuidae insects, <i>cis</i>-11-hexadecenyl aldehyde (<i>Z</i>11-16: Ald), <i>cis</i>-11-hexadecanol (<i>Z</i>11-16: OH), and <i>trans</i>-11-tetradecenyl acetate (<i>E</i>11-14: Ac), showed high binding affinities (Ki = 17.24–18.77 μM). The MmedCSP3 may be involved in locating host insects. Our data provide a base for further investigating the physiological roles of OBPs and CSPs in <i>M</i>. <i>mediator</i>, and extend the function of MmedCSP3 in chemoreception of <i>M</i>. <i>mediator</i>.</p></div

Sequence alignment of all identified OBPs and CSPs in <i>M</i>. <i>mediator</i>.

<p>A: Sequence alignment of OBPs, six conserved cysteine residues are marked in black; B: Sequence alignment of CSPs, four conserved cysteine residues are marked in black. Predicted signal peptides are boxed in the figure.</p

Phylogenetic tree of OBPs and CSPs from Hymenoptera species.

<p>Mmed (red): <i>M</i>. <i>mediator</i>; Ccun (purple): <i>Chouioia cunea</i>; Ssp (green): <i>Sclerodermus sp</i>.; Amel (blue): <i>Apis mellifera</i>.</p

qPCR analysis of <i>MmedOBPs</i> and <i>MmedCSPs</i> expression in different tissues.

<p>The error bars represent standard error and the different small letters above each bar indicate significant differences in transcript abundances (<i>P</i> < 0.05).</p