In situ surface regulation of 3D perovskite using diethylammonium iodide for highly efficient perovskite solar cells.

Surface passivation by constructing a 2D/3D structure is considered to be an effective strategy for suppressing non-radiative recombination and improving the device efficiency and stability. Herein, the 2D perovskite is formed in situ on the surface of a 3D perovskite via chemical interactions between diethylammonium iodide (DAI) and Pb-I octahedra, which greatly reduces the deep level defects and non-radiative recombination. Moreover, the 2D/3D structure can regulate the energy level alignment, enhance the charge extraction, and improve the open-circuit voltage. Finally, compared with the control device, the power conversion efficiency (PCE) of the DAI-treated device increases from 21.58 to 23.50%. The unencapsulated devices stored in air for more than 500 hours can still retain 97% of their initial PCE, revealing good long-term placement stability. This work provides a promising strategy to fabricate efficient PSCs through the in situ construction of 2D/3D perovskite heterojunctions.

Rheological properties and volumetric isothermal expansivity of bamboo kraft black liquor with high solids content and low lignin content.

In this study, a certain percentage of lignin in original bamboo kraft black liquor (BKBL) was separated, and the residual BKBL with low lignin content was expected to be fed into the alkali recovery boiler to reduce the heat transfer load of the alkali recovery boiler. With the decrease in lignin content, the rheological properties/volumetric isothermal expansivity (VIE) of BKBL change. When the lignin content was 70% remaining in the original BKBL, the viscosity of BKBL with low lignin content is close to that of the passivated BKBL at the same solids content, the dynamic viscoelasticity is superior, and the VIE decreases by 57.2%. When the amount of desilication agent is 1.5%, the viscosity of BKBL with low lignin content did not change much, and the VIE increased sharply and was 62.7% higher than that of the passivated BKBL. Therefore, the combination of partial lignin separation process and sodium aluminate desilication process can effectively improve the ability of alkali recovery boiler to deal with BKBL and reduce the influence of "silicon interference".

Interfacial silicon­nitrogen aerogel raise flame retardancy of bamboo fiber reinforced polylactic acid composites.

A triazine derivative containing nitrogen and silicon (SiN) was synthesized and the SiN hybrid aerogel was covered on the surface of bamboo fiber (BF). The modified BF was identified as MBF. The MBF and ammonium polyphosphate (APP) were used to regulate the flame retardancy and mechanical properties of polylactic acid (PLA). The PLA/BF composites were investigated using limiting oxygen index (LOI), UL-94 vertical combustion, cone calorimetry, thermogravimetric analysis linked with infrared spectra (TG-IR) etc. The char residue of MBF at 800 °C is as high as 43.5 % which is 200 % more than that of BF. Incorporating 9 wt% APP generates a PLA9 which displays the UL-94 V2 rating and a LOI value of 28.0 vol%. PLA9/MBF composites display the UL-94 V0 rating and increased LOI values while PLA9/BF composites obtain the UL-94 V2 rating and decreased LOI. The MBF reduces the release of flammable gases during combustion, enhances charring ability and decreases the thermal conductivity of composites. Besides, the tensile and impact strength of PLA9/20MBF is 20 % and 37 % more than that of PLA9/20BF due to stronger interfacial adhesion. This work provides a good method to regulate the flame retardancy and mechanical properties of PLA/BF composites.

Redispersion of dried plant nanocellulose: A review.

Nanocellulose has undergone substantial development as a high value-added cellulose product with broad applications. Dried products are advantageous to decrease transportation costs. However, dried nanocellulose has redispersion challenges when rewetting. In this work, drying techniques, factors affecting redispersibility, and strategies improving the nanocellulose redispersibility are comprehensively reviewed. Hydrogen bonds of nanocellulose are unavoidably developed during drying, leading to inferior redispersibility of dried nanocellulose, even hornification. Drying processes of nanocellulose are discussed first. Then, factors affecting redispersibility are discussed. Following that, strategies improving the nanocellulose redispersibility are analyzed and their advantages and disadvantages are highlighted. Surface charge modification and steric hindrance concept are two main pathways to overcome the redispersion challenge, which are mainly carried out by chemical modification, additive incorporation and non-cellulosic component preservation. Despite several advancements having been achieved, new approaches for enhancing the nanocellulose redispersibility are still required to promote the industrial-scale applications of nanocellulose in various domains.

Contribution Ratio Assessment of Process Parameters on Robotic Milling Performance.

Robotic milling has broad application prospects in many processing fields. However, the milling performance of a robot in a certain posture, such as in face milling or grooving tasks, is extremely sensitive to process parameters due to the influence of the serial structure of the robot system. Improper process parameters are prone to produce machining defects such as low surface quality. These deficiencies substantially decrease the further application development of robotic milling. Therefore, this paper selected a certain posture and carried out the robotic flat-end milling experiments on a 7075-T651 high-strength aeronautical aluminum alloy under dry conditions. Milling load, surface quality and vibration were selected to assess the influence of process parameters like milling depth, spindle speed and feed rate on the milling performance. Most notably, the contribution ratio based on the analysis of variance (ANOVA) was introduced to statistically investigate the relation between parameters and milling performance. The obtained results show that milling depth is highly significant in milling load, which had a contribution ratio of 69.25%. Milling depth is also highly significant in vibration, which had a contribution ratio of 51.41% in the X direction, 41.42% in the Y direction and 75.97% in the Z direction. Moreover, the spindle speed is highly significant in surface roughness, which had a contribution ratio of 48.02%. This present study aims to quantitatively evaluate the influence of key process parameters on robotic milling performance, which helps to select reasonable milling parameters and improve the milling performance of the robot system. It is beneficial to give full play to the advantages of robots and present more possibilities of robot applications in machining and manufacturing.

A novel method for preparing microcrystalline cellulose from bleached chemical pulp using transition metal ions enhanced high temperature liquid water process.

A novel method for preparing microcrystalline cellulose (MCC) from bleached chemical pulp based on the transition metal ion-enhanced high temperature liquid water (HTLW) process was established in this study. Transition metal ions (Fe3+, Cu2+ or Cr3+) were used to enhance the depolymerization effect of HTLW treatment on fibers. Hemicelluloses are selectively removed, resulting in an increase in the α-cellulose content; cellulose undergoes hydrolytic degradation, causing a significant decrease in the average degree of polymerization (DP). SEM images indicated that the as-prepared MCC had granular or rod-like shape. The repose angle results showed a desirable fluidity of obtained MCC. The copper number results showed an increase in the reducing end groups of the obtained MCC. The XRD analysis indicated that the cellulose crystallite exhibited negligible changes, and the crystallization index (CI) increased. However, a very high concentration of transition metal ions lowered the CI. The transition metal ion-enhanced HTLW treatment provides an acid free method for preparing MCC.

A comprehensive and precise set of intervarietal substitution lines to identify candidate genes and quantitative trait loci in oilseed rape (Brassica napus L.).

KEY MESSAGE: A set of intervarietal substitution lines were developed in rapeseed by recurrent backcrossing and marker-assisted selection and employed for mapping both qualitative and quantitative traits. Intervarietal substitution lines (ISLs) may be assembled into advanced secondary mapping populations that have remarkable potential for resolving trait loci and mapping candidate genes. To facilitate the identification of important genes in oilseed rape (canola, Brassica napus), we developed 89 ISLs using an elite cultivar 'Zhongyou 821' (ZY821) as the recipient and a re-synthesized line 'No.2127' as the donor. In the whole process of ISLs development, the target chromosome segments were selected based on the genotypes of 300 microsatellite markers evenly distributed across the genome. Eighty-nine ISLs fixed at BC5F4 were genotyped by sequencing using double digestion to survey the lengths of target substitution segments from the donor parent and the background segments from the recurrent parent. The total length of the substituted chromosome segments was 3030.27 Mb, representing 3.56 × of the Darmor-bzh reference genome sequence (version 4.1). Gene mapping was conducted for two qualitative traits, flower colour and seed-coat colour, and nine quantitative traits including yield- and quality-related traits, with 19 QTLs identified for the latter. Overlapping substitution segments were identified for flower colour and seed-coat colour loci, as well as for QTLs consistently detected in 2 or 3 years. These results demonstrate the value of these ISLs for locus resolution and subsequent cloning, targeted mutation or editing of genes controlling important traits in oilseed rape.

High-density ddRAD linkage and yield-related QTL mapping delimits a chromosomal region responsible for oil content in rapeseed (Brassica napus L.).

Rapeseed (Brassica napus L.) is one of the most important oil crops almost all over the world. Seed-related traits, including oil content (OC), silique length (SL), seeds per silique (SS), and seed weight (SW), are primary targets for oil yield improvement. To dissect the genetic basis of these traits, 192 recombinant inbred lines (RILs) were derived from two parents with distinct oil content and silique length. High-density linkage map with a total length of 1610.4 cM were constructed using 1,329 double-digestion restriction site associated DNA (ddRAD) markers, 107 insertion/deletions (INDELs), and 90 well-distributed simple sequence repeats (SSRs) markers. A total of 37 consensus quantitative trait loci (QTLs) were detected for the four traits, with individual QTL explained 3.1-12.8% of the phenotypic variations. Interestingly, one OC consensus QTL (cqOCA10b) on chromosome A10 was consistently detected in all three environments, and explained 9.8% to 12.8% of the OC variation. The locus was further delimited into an approximately 614 kb genomic region, in which the flanking markers could be further evaluated for marker-assisted selection in rapeseed OC improvement and the candidate genes targeted for map-based cloning and genetic manipulation.

Molecular simulation study of adsorption and diffusion on silicalite for a benzene/CO2 mixture.

The adsorption and diffusion of a binary mixture of supercritical CO2 and benzene on silicalite (MFI-type) have been studied through the grand canonical Monte Carlo and molecular dynamics (MD) simulations. The adsorption behavior of pure CO2 on silicalite was discussed in detail from the adsorption isotherms, adsorption sites, interaction energies, and isosteric heats of adsorption. For the mixture, the influences of temperature, pressure and composition on the adsorption isotherms have been examined. The adsorption site behavior of the mixture has been analyzed, and benzene molecules get adsorbed preferentially in the more spacious channel intersection positions. These simulation results suggest that SC-CO2 fluid can be used as an efficient desorbent of larger aromatics in the zeolite material. The diffusion characteristic for the benzene/CO2 mixture was studied on the basis of MD simulation. It was found that the large coadsorbed benzene molecule has a pronounced effect on the CO2 diffusion in the mixture, while the mobility of benzene molecules is very small due to geometrical restrictions.