A Highly Efficient,Blue‐Phosphorescent Device Based on a Wide‐Bandgap Host/FIrpic: Rational Design of the Carbazole and Phosphine Oxide Moieties on Tetraphenylsilane

A new series of wide‐bandgap materials, 4‐dipenylphosphine oxide‐4′‐9H‐carbazol‐9‐yl‐tetraphenylsilane (CSPO), 4‐diphenylphosphine oxide‐4′,4″‐di(9H‐carbazol‐9‐yl)‐tetraphenylsilane (pDCSPO), 4‐diphenylphosphine oxide ‐4′‐[3‐(9H‐carbazol‐9‐yl)‐carbazole‐9‐yl]‐tetraphenylsilane (DCSPO), 4‐diphenylphosphine oxide‐4′,4″,4″′‐tri(9H‐carbazol‐9‐yl)‐tetraphenylsilane (pTCSPO) and 4‐diphenylphosphine oxide ‐4′‐[3,6‐di(9H‐carbazol‐9‐yl)‐9H‐carbazol‐9‐yl]‐tetraphenylsilane (TCSPO), containing different ratios and linking fashions of p‐type carbazole units and n‐type phosphine oxide units, are designed and obtained. DCSPO is the best host in FIrpic‐doped devices for this series of compounds. By utilizing DCzSi and DPOSi as hole‐ and electron‐transporting layers, a high EQE of 27.5% and a maximum current efficiency of 49.4 cd A^?1 are achieved in the DCSPO/FIrpic doped device. Even at 10 000 cd m^?2, the efficiencies still remain 41.2 cd A^?1 and 23.0%, respectively.     

Femtocell网络安全问题的分析与研究

分析Femtocell网络的安全威胁问题,提出三大安全问题的爆发点:空中接口、用户接入终端以及IP公网,针对每个爆发点分析可能出现的安全问题,并提出相应的解决方案。     

硫粉改性Mo基耐硫甲烷化催化剂

采用常规的H2S/H2混合气硫化方式和硫粉改性的硫化方式对15%(w)Mo/Al2O3和20%(w)Mo/25%(w)CeO2-Al2O3催化剂进行硫化处理,并考察了两种硫化方式处理的催化剂的耐硫甲烷化性能。实验结果表明,在600℃下,硫粉改性硫化处理的15%(w)Mo/Al2O3和20%(w)Mo/25%(w)CeO2-Al2O3催化剂上的CO转化率分别为60.3%和71.0%,而常规硫化方式处理的两种催化剂上的CO转化率仅为49.8%和61.2%,硫粉改性硫化的效果明显优于常规硫化。结合N2吸附-脱附、XRD、Raman光谱、XRF等表征手段对两种不同硫化方式处理的催化剂进行物相和结构分析的结果表明,两种硫化方式均能实现MoO3的完全转化,而硫粉改性的硫化方式可以促进Mo的硫化,提高n(S)∶n(Mo),使催化剂中出现晶态的MoS2。     

Using homomorphic encryption to secure the combinatorial spectrum auction without the trustworthy auctioneer

Spectrum auction is an enabling technology for improving the spectrum efficiency of unused licensed bands (white spaces) in wireless networks. However, the back-room dealing (i.e., the frauds of the untrustworthy auctioneer and the bid-rigging between the greedy bidders and the insincere auctioneer) poses serious security challenges, leading to failures of all existing secure auction designs in allocating spectrum bands. In this paper, we propose a secure combinatorial spectrum auction (SCSA) by utilizing homomorphic encryption to prevent the back-room dealing. The idea in SCSA is to incorporate cryptographic techniques into the spectrum auction to address the frauds and bid-rigging. It computes and reveals the results of spectrum auction while the actual bidding values of bidders are kept confidential. SCSA also provides a corresponding procedure in implementing the combinatorial spectrum auction under the interference constraints. We show that compared with existing secure spectrum auction designs against the untrustworthy auctioneer, SCSA is much more efficient in both communication and computational complexity; and compared with other spectrum auction designs with security consideration, SCSA can effectively thwart the back-room dealings due to the untrustworthy auctioneer without too much performance degradation.     

对向靶溅射TiN薄膜的结构和物性

利用对向靶溅射（ＦＴＳ）沉积出（１１１）择优取向的单相ＴｉＮ膜，膜硬度（ＨＶ）最高可达３８００，择优取向随基板偏压增高，可由（１１１）转向（２００），晶格常数随氮气分压增高而增大，这是氮原子进入四面体间隙引起的。     

Integrated chemo- and biocatalytic processes: a new fashion toward renewable chemicals production from lignocellulosic biomass

Concerns over climate change and environmental pollution resulting from petroleum refining has spurred the exploitation of green replacements for producing chemicals and fuels. Valorization of lignocellulosic biomass into chemicals represents a promising alternative to petroleum refining. Biological and chemical catalysis are two leading routes for lignocellulose variolization, but strategies relying simply on biological or chemical conversion have shown limitations. Integrating biocatalysts with chemocatalysts could leverage the inherent strengths of both while circumventing their respective disadvantages, benefiting product yield and selectivity, and reducing cost and waste generation. This review focuses on the coupled chemocatalytic and biocatalytic synthesis of renewable chemicals from polysaccharides and their derived platform chemicals. In addition, strategies for producing value-added products from lignin via integrated chemical depolymerization and biological conversion are highlighted. The techno-economics of integrating chemocatalysts and biocatalysts in producing chemicals in the context of biorefinery are also discussed. Finally, perspectives on designing integrated chemical and biological catalysis for renewable chemicals production are provided. © 2022 Society of Chemical Industry (SCI).     

Ascidian-Inspired Temperature-Switchable Hydrogels with Antioxidant Fullerenols for Protecting Radiation-Induced Oral Mucositis and Maintaining the Homeostasis of Oral Microbiota

A key characteristic of radiation-induced oral mucositis (RIOM) is oxidative stress mediated by the “reactive oxygen species (ROS) storm” generated from water radiolysis, resulting in severe pathological lesions, accompanied by a disturbance of oral microbiota. Therefore, a sprayable in situ hydrogel loaded with “free radical sponge” fullerenols (FOH) is developed as antioxidant agent for RIOM radioprotection. Inspired by marine organisms, 3,4,5-trihydroxyphenylalanine (TOPA) which is enriched in ascidians is grafted to clinically approved temperature-switchable Pluronic F127 to produce gallic acid (containing the TOPA fragment)-modified Pluronic F127 (MGA) hydrogels to resist the fast loss of FOH via biomimetic adhesion during oral movement and saliva erosion. Based on this, progressive RIOM found in mice is alleviated by treatment of FOH-loaded MGA hydrogels whether pre-irradiation prophylactic administration or post-irradiation therapeutic administration, which contributes to maintaining the homeostasis of oral microbiota. Mechanistically, FOH inhibits cell apoptosis by scavenging radiation-induced excess ROS and up-regulates the inherent enzymatic antioxidants, thereby protecting the proliferation and migration of mucosal epithelial cells. In conclusion, this work not only provides proof-of-principle evidence for the oral radioprotection of FOH by blocking the “ROS storm”, but also provides an effective and easy-to-use hydrogel system for mucosal in situ administration.     

Relay Catalysis of Multi-Sites Promotes Oxygen Reduction Reaction

The two-electron pathway to form hydrogen peroxide (H₂O₂) is undesirable for the oxygen reduction reaction (ORR) in iron and nitrogen doped carbon (Fe–N–C) material as it not only lowers the catalytic efficiency but also impairs the catalyst durability. In this study, a relay catalysis pathway is designed to minimize the two-electron selectivity of Fe–N–C catalyst. Such a design is achieved by introducing two other sites, that is, MnN₄ site and α-Fe(110) face. A combination of transmission electron microscopy image and X-ray absorption spectra verify the three site formation. Electrochemical test coupled with post-treatment confirm the improvement of MnN₄ site and α-Fe(110) face on catalyst performance. Theoretical calculation proposes a relay catalysis pathway of three sites, that is, H₂O₂ released from the FeN₄ site migrates to the MnN₄ site or α-Fe(110) face, on which the captive H₂O₂ is further reduced to H₂O. The relay catalysis pathway positioned the as-prepared catalyst among the best ORR catalysts in both aqueous electrode and alkaline direct methanol fuel cell test. This study examples an interesting relay catalysis pathway of multi-sites for the ORR, which offers insights into the design of efficient electrocatalysts for fuel cells or beyond.     

A Magnetic Cloud Bomb for Effective Biofilm Eradication

Skin and soft tissue infection (SSTI) is an inflammatory condition caused by bacteria, and the eradication of biofilms is an important problem when treating such infections. Because of the low dispersibility and biofilm permeability of magnetic antibacterial materials, biofilm removal is difficult and infection persists. To solve these problems, inspired by conventional cloud bombs, a magnetic “nano-cloud bomb” by adjusting the synthesis ratio to alter the shape of an assembled zeolitic imidazolate framework (ZIF), namely ZIF-L-Fe, is synthesized simply and rapidly. ZIF-L-Fe has a flower-like clustered structure with sharp edges, which prevents the stacking of 2D ZIF nanoleaves, thereby enhancing the dispersion of Fe nanoparticles and increasing biofilm penetration under the action of magnetism. Additionally, ZIF-L-Fe retains the photothermal and catalytic properties of nanoparticles, which can kill methicillin-resistant Staphylococcus aureus (MRSA) at low temperature and efficiently catalyze hydrogen peroxide (H₂O₂). Because of its magnetic effect, ZIF-L-Fe can rapidly penetrate biofilm, thus forming craters and destroying the local biofilm structure. Accordingly, the proposed strategy of clustered ZIF-loaded delivery of Fe provides a novel concept that requires further development for clinical application to the treatment of biofilm infections.