No abstract

Morella rubra, red bayberry, is an economically important fruit tree in south China. Here, we assembled the first high-quality genome for both a female and a male individual of red bayberry. The genome size was 313-Mb, and 90% sequences were assembled into eight pseudo chromosome molecules, with 32 493 predicted genes. By whole-genome comparison between the female and male and association analysis with sequences of bulked and individual DNA samples from female and male, a 59-Kb region determining female was identified and located on distal end of pseudochromosome 8, which contains abundant transposable element and seven putative genes, four of them are related to sex floral development. This 59-Kb female-specific region was likely to be derived from duplication and rearrangement of paralogous genes and retained non-recombinant in the female-specific region. Sex-specific molecular markers developed from candidate genes co-segregated with sex in a genetically diverse female and male germplasm. We propose sex determination follow the ZW model of female heterogamety. The genome sequence of red bayberry provides a valuable resource for plant sex chromosome evolution and also provides important insights for molecular biology, genetics and modern breeding in Myricaceae family.

Chemical looping combustion (CLC) with syngas, a synthesized gas mixture of CO, H 2 , CO 2 , H 2 O(g), N 2 , and H 2 S, was investigated using thermodynamic simulation, with focus on carbon deposition and sulfur evolution in CLC. Five metal oxides, such as NiO, CuO, Fe 2 O 3 , Mn 3 O 4 , and CoO, were selected as oxygen carriers for CLC application. Different influencing factors on the formation of carbon deposits were investigated, including pressure, fuel reactor (FR) temperature, oxygen excess number Φ (denoting the availability of lattice oxygen in the oxygen carrier to the fuel), and fuel gas composition. Higher temperature and larger oxygen excess number Φ inhibited the formation of carbon deposits while the pressurized condition caused the opposite. The increase of H 2 O(g) and CO 2 fraction in syngas reduced carbon deposition while, in contrast, a larger H 2 S occurrence in syngas led to more carbon deposits to be formed. A sensitivity analysis to the different factors revealed that carbon deposition was mainly determined by the FR temperature and the oxygen carriers provided while other factors played a minor role. In addition, the predominant C-bearing species and their distributions at different temperatures were thermodynamically investigated. At low FR temperature and oxygen-deficient condition (i.e., oxygen excess number Φ < 1), the predominant carbon species as solid deposits were mainly elemental carbon or carbonates for NiO, CuO, Fe 2 O 3 , and CoO while MnC 2 and MnCO 3 were the main species for Mn 3 O 4 . In terms of the evolution of sulfur in CLC with syngas containing a basic composition of CO, N 2 , H 2 , and H 2 S, the low pressure, high temperature, and adequate lattice oxygen would make more sulfur species form in the gas phase. After that, CO 2 and H 2 O(g) were introduced into the syngas, and they were found to possibly serve as additional oxidizers to convert H 2 S into SO 2 . The oxidation function of CO 2 was slightly stronger than that of steam. Again, the evolution and distribution of various sulfur species was studied. For four metal oxides (NiO, Fe 2 O 3 , Mn 3 O 4 , and CoO), the most possible solid sulfur compounds were Ni 3 S 2 , Fe 0.84 S, MnSO 4 , and Co 0.89 S, respectively. But for CuO, at Φ < 1, Cu 2 S was the main solid sulfur compound while at Φ > 1 CuSO 4 and Cu 2 SO 4 dominated.

No abstract

The use of mineral materials as oxygen carriers for Chemical Looping Combustion (CLC) is an attractive option due to their low cost. This paper reports an experimental study of four manganese minerals as potential oxygen carriers focusing on the behaviour in CLC as well as in Chemical Looping with Oxygen Uncoupling (CLOU). Experiments were carried out in a thermogravimetric apparatus (TGA) and a fluidized-bed reactor. Repeated tests with all the minerals showed no sufficient CLOU properties. Then, they can only be used in CLC applications involving the redox pairs Mn 3 O 4 /MnO and Fe 2 O 3 /Fe 3 O 4. Oxygen transport capacity and reactivity to the main fuel gases (H 2 , CO and CH 4) were determined in a TGA with gaseous fuels. Manganese minerals were also tested during 35-54h in a fluidized-bed reactor to evaluate the evolution of reactivity to H 2 , CO and CH 4, as well as their attrition rate and mechanical strength. The reactivity of the materials decreased in the first 10 cycles with CH 4 and then became quite stable for the rest of the cycles performed with CH 4 , CO and H 2. In comparison to previously tested Fe-based minerals, lower reactivity with CH 4 was found for the manganese minerals. However, in terms of CO and H 2 combustion, their reactivity was adequately high. During the tests, agglomeration and de-fluidization were never found for any material. Mechanical crushing strength of the particles decreased with cycles, which led to the increase of attrition rate of some materials above acceptable levels. Nevertheless, materials with adequate crushing strength and low attrition were identified. Combining the reactivity

Chemical looping combustion (CLC) has emerged as an efficient and promising combustion technique for fossil fuels during the past few decades. The main advantages of CLC lie in its inherent CO 2 sequestration and cascade energy utilization, being primarily benefited from the in situ reactive separation facilitated by the circulation of a solid intermediate. Up to date, the research on the CLC-related oxygen carrier, reactor, and system has made extensive and in-depth development worldwide. CLC units with thermal power ranging from the kW th to MW th scale were demonstrated with fuels of different types (gaseous, liquid, and solid fuels). Over the past 20 years, Chinese researchers have made significant progress in chemical looping technologies, extending from fundamental oxygen carrier studies to the implementation of pilot-scale CLC units. For the use of solid fuels, such as coal, in CLC, it is a rather challenging task but a lot of opportunities also remain. As a result of the particular "rich coal, meager oil, and deficient gas" energy reserve characteristics, China has become the main research battlefield on CLC of coal these years. In this paper, the main advances and research status on CLC of coal in China are reviewed and appraised. The contents in this paper cover most of, if not all, the research hotspots on CLC of coal, i.e., oxygen carrier screening, reactor design/construction/operation, pollutant emission, reaction kinetics, and numerical simulation. Chinese researchers have made substantial contributions to two bottleneck issues faced by the coal-derived CLC technique, i.e., developing and preparing a low-cost while well-performing oxygen carrier and promoting the slow char gasification process in the fuel reactor. In addition, remaining challenges that constrain the development of large-scale CLC units and indeed deserve in-depth investigation are analyzed. Particular attention is paid to the following three key challenges: severe mismatch of reaction rates in CLC of coal, difficulty in attaining a good balance between the oxygen carrier performance and cost, and challenge in controlling solid circulation to manage heat and mass transfer. Accordingly, potential opportunities for future research and scaling-up of the coal-derived CLC technique are discussed. The academic thoughts that are highlighted here include (1) achieving a good compromise between the oxygen carrier cost and performance through the rational design of a multifunctional and composite oxygen carrier and its scalable preparation using cheap raw materials, (2) coordination among reactor modeling− reactor design−reactor operation to attain effective management of heat and mass transfer in the CLC reactor, and (3) a complex while effective matching matrix among coal type, oxygen carrier particle, and reactor configuration to acquire the optimal performance of the whole CLC system. Overall, this review summarizes the contributions of Chinese scholars to CLC of coal and presents how these research achievements benefit the commercial-sca...

CuO-CuO heterojunction was synthesized via a one-step flame spray pyrolysis (FSP) process and employed as photoactive material in construction of a photoelectrochemical (PEC) sensing device. The surface analysis showed that CuO-CuO nanocomposites in the size less than 10 nm were formed and uniformly distributed on the electrode surface. Under visible light irradiation, the CuO-CuO-coated electrode exhibited admirable cathodic photocurrent response, owing to the favorable property of the CuO-CuO heterojunction such as strong absorption in the visible region and effective separation of photogenerated electron-hole pairs. On the basis of the interaction of l-cysteine (l-Cys) with Cu-containing compounds via the formation of Cu-S bond, the CuO-CuO was proposed as a PEC sensor for l-Cys detection. A declined photocurrent response of CuO-CuO to addition of l-Cys was observed. Influence factors including CuO-CuO concentration, coating amount of CuO-CuO, and applied bias potential on the PEC response toward l-Cys were optimized. Under optimum conditions, the photocurrent of the proposed sensor was linearly declined with increasing the concentration of l-Cys from 0.2 to 10 μM, with a detection limit (3S/N) of 0.05 μM. Moreover, this PEC sensor displayed high selectivity, reproducibility, and stability. The potential applicability of the proposed PEC sensor was assessed in human urine samples.

Chemical-looping combustion (CLC) is a very promising technology to combine the energy-utilization situation in China and CO2 zero-emission in situ allowing for CO2 sequestration by efficient and energy-saving ways and without nitrogen oxide (NO x ) formation. Having an oxygen carrier with sufficient reactivities in reduction and oxidation and enough recyclability and strength for long-term operation is one of the key issues of the CLC process. This paper focuses on the investigation of Ni-based oxygen carriers for CLC by coal char. First, Al(OC3H7)3 and Ni(NO3)2 are selected as the main raw materials to prepare sol–gel-derived NiO/NiAl2O4 oxygen carriers. The oxygen carrier with a mass content of 60% NiO, a sintering temperature of 1300 °C, and a sintering time of 6 h performs comparatively well. Second, the reduction reaction of the NiO/NiAl2O4 oxygen carriers with char and the circular reduction/oxidation reactions of the NiO/NiAl2O4 oxygen carriers with char/air or hydrogen/air are carried out in a thermogravimetric analysis (TGA) instrument to investigate the reactivities and chemical life of the prepared NiO/NiAl2O4 oxygen carriers. The experimental results show that (a) when the TGA temperature is higher than 850 °C, NiO/NiAl2O4 starts to react with coal char rapidly, which indicates that CLC of coal char using NiO/NiAl2O4 as oxygen carriers is a feasible technology of energy utilization in principle; (b) NiO/NiAl2O4, which maintains its activity over single-cycle reduction/oxidation reactions with char/air or multiple-cycle reduction/oxidation reactions with hydrogen/air, exhibits extremely good recyclablity; (c) the porous beehive structure of the NiO/NiAl2O4 particle is maintained, and the sintering behavior between different particles is not observed during cyclic studies. Those experimental results prove the sol–gel-derived oxygen carrier NiO/NiAl2O4 is capable of being used in chemical-looping combustion fueled by coal char or H2.