Design of novel CNT/RGO/ZIF-8 ternary hybrid structure for lightweight and highly effective microwave absorption.

Carbon-nanotube-based composites are highly desirable for addressing the difficulties relevant to the quality of electromagnetic wave absorbers. The introduction of lightweight nanocomposites for constructing new structures has been widely studied due to the transformation in impedance matching and attenuation. In this paper, a novel carbon nanotube-graphene oxide-zeolitic imidazolate framework-8 (CNT/RGO/ZIF-8) ternary hybrid structure was successfully fabricated by a facile solvothermal process. The ZIF-8 was entangled initially by carbon nanotubes via the π-π interaction between organic ligands and benzene ring structure in CNT. Then, the CNT/ZIF-8 composite was immobilized on the surface of RGO by interacting with the active functional group of RGO. The structure and performance for CNT, CNT/ZIF-8, and CNT/RGO/ZIF-8 were compared to investigate the interaction mechanisms between components, and CNT/ZIF-8 exhibited a distinct improvement for microwave absorption performance. Furthermore, the introduction of RGO can accelerate the amelioration of absorption characteristics. The interfacial bonding between CNT, RGO, and ZIF-8 exerts a great influence on the absorbing quality. The mechanism of absorption of electromagnetic waves was explained by the synergistic effects of conduction loss, polarization behaviors, and eddy current. The unique structure could offer new insights to exploit advanced microwave-absorption materials.

Design of a novel carbon nanotube and metal-organic framework interpenetrated structure with enhanced microwave absorption properties.

The exploitation of carbon nanotube (CNT) and metal-organic framework (MOF) composite materials has been highly desirable in a number of applications. However, the construction of high dispersibility and stability CNT/MOF complex structures is still an enormous challenge. Herein, a novel assembly method is established for the construction of a CNT/Ni-MOF (0.1 CNT/MOF, 0.2 CNT/MOF, 0.3 CNT/MOF) interpenetrated structure by a solvothermal process. The MOFs can be robustly anchored on the surface of CNTs. Through a series of characterizations, the MOF can be comfortably integrated into the CNT fibers, which exhibits the enhancement of carrier mobility and fluorescence properties. The microwave absorption properties of the CNT/MOF are explored by a vector network analyzer. The 0.1 CNT/MOF has a maximum absorption of -9.2 dB at 18 GHz with a thickness of 5 mm, while the 0.2 CNT/MOF has a maximum absorption of -24.32 dB at 4.5 GHz with a thickness of 5 mm, a performance maximum. Therefore, the 0.2 CNT/MOF structures are potential candidates to ameliorate the microwave absorption properties.

Mid-term outcomes in patients undergoing tricuspid valve repair with rheumatic tricuspid valve disease / 中华胸心血管外科杂志

Objective The aim of this study was to summarize the characteristics of rheumatic tricuspid valve disease ( RTVD) and to evaluate the mid-term outcomes in patients undergoing tricuspid valve repair with RTVD. Methods Between January 2009 and June 2016, 251 consecutive patients with rheumatic heart disease( RHD) underwent left-sided valvular re-placement by a single surgeon. We analyzed 39 patients with RTVD which was diagnosed during the operation. Among them, 32 patients, with moderate or higher tricuspid regurgitation( TR) , were compared with other 59 patients of functional tricuspid regurgitation( FTR) for a better understanding of the features of the RTVD. A total of 39 patients were categorized into 2 groups:Ring annuloplasty group(n=33) and non-Ring annuloplasty group(n=6) which consisted of modified De Vega annu-loplasty for 4 patients and edge-to-edge repair for 2. Meanwhile, 13 of them underwent concomitant tricuspid commissurotomy and 1 patient had a tricuspid leaflet augmentation procedure. We analyzed the mid-term outcomes of 22 patients( follow-up du-ration>1 year)with a mean follow-up duration of(45.5 ±25.1) months. Results Compared with FTR, patients with RTVD had higher preoperative TR grade(3.1 ±0.8 vs. 2.6 ±0.7, P=0.004) but with lower preoperative PASP[(53.8 ±19.4) mmHgvs.(63.6±21.5)mmHg,P=0.037)](1mmHg=0.133kPa) andtricuspidannulusdiameter(TAD) thatobserved bothinpreoperativeechocardiogramtests[(37.0±5.7)mmvs.(41.9±6.7)mm,P=0.018)]andintraoperativedetection [(35.6±4.1)mmvs.(39.9±6.5)mm,P=0.000)] . TherewasnoearlymortalityandresidualmoderateorhigherTR grades in either group. Compared with patients in non-ring annuloplasty group, patients in ring annuloplasty group showed low-er postoperative TR grade(0. 2 ± 0. 4 vs. 0. 7 ± 0. 5, P=0. 039) and acceptable TR grade(0. 8 ± 0. 5 vs. 1. 3 ± 1. 9, P>0. 050) during the mid-term follow-up. PASP, the peak diastolic velocity and pressure gradient across tricuspid valve were not different between groups in preoperative, postoperative and follow-up. Conclusion Compared with FTR, Patients with RTVD had lower preoperative PASP and TAD, but with a higher preoperative TR grade. In our study, ring annuloplasty showed simi-lar mid-term outcomes compared with other procedures.