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In this paper, the nanofiller consisting of graphene oxide (GO) and organically modified hydrotalcite (HT) was fabricated via the electrostatic self-assembly and further reduced and incorporated into the polyimide (PI) matrix to prepare superior nanocomposite films with high energy storage density. It was observed by transmission electron microscopy (TEM) that the insulating HT facesheets were attached well onto the GO film to form a stable sandwich structure. The synthesized ternary nanocomposite film (1.0 rGO@HT/PI) showed high breakdown strength of 175.9 kV/mm and ultra-high dielectric constant at 10 kHz (er = 35.4), about 10 folds more than pure PI (er = 3.4), resulting in a maximum energy storage density of 4.84 J/cm3. On account of electrostatic self-assembly, HT nanosheets can efficiently reduce the contact area between graphene oxides and inhibit the formation of conductive networks, thus maintaining a high level of breakdown strength and increasing the energy storage density of the nanocomposite films.

Three novel dianhydride monomers involving amide groups were synthesized and further polymerized with various diamines to afford a series of colorless polyimides (cPI). The resultant cPI films present outstanding optical performance, exceedingly good dimensional stability at high temperature, great film ductility and solution-processability. In particular, chemically imidized AMDA/TFDB has an ultra-low coefficient of thermal expansion value of 5.2 ppm K−A, a relatively high Tg value of 333 °C and large elongation at break of 29%, resulting from its rigid-rod backbone and the formation of hydrogen bonding (–CO⋯NH–) between adjacent molecular chains. Concurrently, it exhibits a high optical transmittance of 87% at a wavelength of 550 nm, a small haze value of 0.71 and low yellow index of 4.29 by reason that the incorporation of bulky trifluoromethyl and cyclohexyl preclude the formation of a charge transfer complex effectively. The high overall performance of the amide-containing cPI films suggests its potential application in the field of flexible OLED displays.

A series of polymer substrates based on the polyimides (PIs) containing diphenylpyridine for flexible OLED displays were successfully fabricated by the incorporation of graphene oxide (GO) and organically modified layered double hydroxide (OLDH) nanosheets. In comparison with pristine PI, the OTR and WVTR of PI nanocomposite films at a loading of 3% OLDH were reduced by 78% and 25.7%, respectively, whereas by incorporation of 0.3% GO, the OTR and WVTR of PI nanocomposite films declined by 85.5% and 31.8%, respectively. The results revealed that GO nanosheets could have a great advantage over OLDH from the aspect of improving the gas barrier performance. Moreover, compared with the pristine PI films (CTE: 4.73 ppm K−1), the incorporation of GO and OLDH nanosheets was of great benefit in reducing the CTE value, such as 1.57 ppm K−1 for PIL-3.0 and 3.33 ppm K−1 for PIG-0.3, while maintaining high Tg values exceeding 450 °C and excellent thermal stability. The resulting PI nanocomposite films showed improved barrier properties without sacrificing the thermal and mechanical performance, and could serve as a promising candidate for substrate materials of flexible OLED displays.

Supplemental Material for Transparent polyimide films with ultra-low coefficient of thermal expansion by Tingting Zhang, Zhenghui Yang, Fengyu Piao, Haiquan Guo in High Performance Polymers

Three-photon absorption (3 PA) in the near IR region is among the most prominent nonlinear optical (NLO) effects and has attractive applications in chemical/biological sensing and imaging. Yet, rationally constructed molecules with small molecular weight and reasonable 3 PA cross-section has been rarely reported. Herein, we designed a novel three-photon absorption photostable luminogen (namely X1) with enhanced aggregation induced emission (AIE) and the ability to achieve multi-photon imaging with femtosecond laser excitation. X1 was constructed from diaminobenzene and diethylamino salicylaldehyde forming a novel di-Schiff base. It possesses a large conjugated delocalization which exhibits large three-photon absorption (3 PA) cross-section values. We also showed that by using a suitable delivery vector, X1 compound could applied as a live cell imaging probe thus providing a valuable tool to study lipid droplets/lysosome interaction in depth tissues.

With the continuous development of computer hardware and software technology, mixed reality has been emerged. It has been applied in many industries. However, the use in nuclear power engineering is little. The current design data of nuclear power mainly uses 2D drawings and 3D models, which is not conducive to collaborative design and design verification. In the maintenance process of Nuclear Power Plant, the staff has to carry the manual, and can’t get real-time guidance. Teaching methods of technology and skill for staffs are a little boring and inefficient. It is possible to solve these problems by using mixed reality with Hololens. The sharing feature of Hololens is helpful to collaborative design. Rich holographic images and easy interactions of Hololens help maintenance workers get tasks done faster. The training system of HPR1000 is developed, which provides the nuclear power staffs with the content of HPR1000 plant layout and key equipments in the form of holographic images.

The Bouguer correction is an important item in gravity reduction, while the traditional Bouguer correction, whether the plane Bouguer correction or the spherical Bouguer correction, exists approximation error because of far-zone virtual terrain. The error grows as the calculation point gets higher. Therefore gravity reduction using the Bouguer correction with limited range, which was in accordance with the scope of the topographic correction, was researched in this paper. After that, a simplified formula to calculate the Bouguer correction with limited range was proposed. The algorithm, which is innovative and has the value of mathematical theory to some extent, shows consistency with the equation evolved from the strict integral algorithm for topographic correction. The interpolation experiment shows that gravity reduction based on the Bouguer correction with limited range is prior to unlimited range when the calculation point is taller than 1000 m.

The flexibility of organic light-emitting diode (OLED) displays highly depends on the properties of the flexible substrates. In this paper, a series of aromatic polyimides have been fabricated via the copolycondensation of pyromellitic dianhydride (PMDA), the two different rigid heterocyclic diamines, 2,5-bis(4-aminophenyl)pyrimidine (PRM) or 2,5-bis(4-aminophenyl)pyridine (PRD), and another flexible diamine, 4,4′-oxydianiline (ODA). The performance of the polyimide films could be systematically tailored by means of adjusting the main-chain rigidity, as well as the close packing and orientation of polymer chains by the formation of the intermolecular hydrogen bonds between poly(amic acid)s. The optimal results (PIb-4, PIb-5, PIc-2) showed that the polyimides were endowed with ultra-high glass transition temperature (Tg) exceeding 450 °C, low coefficient of thermal expansion (CTE) at 0–5 ppm K−1 and excellent thermal stability (Td5% = 570–590 °C). Meanwhile, all of them exhibited sufficient flexibility, the elongation at break at of 40–60%, extremely high tensile strength of 250–380 MPa and modulus of 4.1–6.1 GPa. Hence, the polyimide films should be the promising candidates for application as the polymer substrates for flexible OLED displays.

Lipid droplets (LDs) ultrastructure progression under proteohormone stimulation provide valuable clues for understanding conditions associated with obesity and diabetes. Current available LDs probes either alter intra-LDs environments or lack photo-resistance; thus, this research domain is poorly understood. In this work, a N-B-O type BODIPY- hexylcarbazole derivative named BoCz-Lip was rationally designed while achieving specific LDs live-cell targeting. BoCz-Lip showed minimal impact on cell viability as well as internal LDs' protein, triglyceride and cholesterol level. Along with its good photostability, it can be used to monitor LDs evolution under super-resolution nanoscopy. More importantly, we concluded how proteohormone could influence LDs ultrastructure, offering a better understanding for correlating diseases at the nanoscale.

Nowadays, operators often need to install and disassemble key equipment according to the technical drawings or documents in the process of nuclear construction and maintenance. It’s more dependent on personal skills, experience and environmental impact in this scenario, also with higher error rate. On the other hand, two-dimensional drawings and documents are aimed to reflect the design parameters and specifications of equipment. However, drawing cannot give the on-site operators a three-dimensional and intuitive feeling, and it affects the accuracy of the operator’s judgment. On the basis of in-depth analysis of technical characteristics of nuclear power key equipment and the on-site job requirements, this paper puts forward the method of two-dimensional drawing recognition and 3D model visualization based on augmented reality technology. It also forms an application on the mobile platform, superimposes the 3-D model and drawing in one viewport and provides necessary interaction. By the achievement of this paper, the digitalized, virtualized and intelligentized on-site operation processes in nuclear power plant are optimized, and the operating efficiency and accuracy are improved. At the same time, a new experience and implementation scheme for equipment maintenance analysis, preview and staff training are provided.

Using the first-principles calculation and the electronic conductivity relaxation (ECR) experimental technique, we investigated the adsorption and dissociation behaviors of O2 on Pt-modified La0.625Sr0.375Co0.25Fe0.75O3-δ (LSCF) surface. Toward the O2 reduction, the calculation results show that the perfect LSCF (100) surface is catalytically less active than both the defective (100) surface and the perfect (110) surface. O2 molecule can weakly adsorb on the perfect LSCF (100) surface with a small adsorption energy of about -0.30 eV, but the dissociation energy barrier of the O2 molecule is about 1.33-1.43 eV. Doping of Pt cluster on the LSCF (100) surface can remarkably enhance its catalytic activity. The adsorption energies of O2 molecules become -1.16 and -1.89 eV for the interfacial Feint site and the Ptbri bridge site of Pt4-cluster, respectively. Meanwhile, the dissociation energy barriers are reduced to 0.37 and 0.53 eV, respectively. The migration energy barrier of the dissociated oxygen from the interfacial Pt to the LSCF surface is 0.66 eV, and it is 2.58 eV from the top site of the Pt cluster to the interfacial Pt site, suggesting that it is extremely difficult for oxygen to migrate over the Pt cluster. The Bader charge analysis results further indicate that the charges transferring from Pt cluster to LSCF surface promote the adsorption and dissociation of O2 molecules. Experimentally, a dramatic decrease of the surface oxygen exchange relaxation time was observed on Pt-modified LSCF cathode, with a chemical surface exchange coefficient increased from 6.05 × 10(-5) cm/s of the bare LSCF cathode to 4.04 × 10(-4) cm/s of the Pt-modified LSCF cathode, agreeing very well with our theoretical predictions.