Terahertz Transmission Properties of Split Ring Resonator Arrays

The transmission properties of double-ring split ring resonator(SRR) arrays and closed ring resonator arrays are measured using terahertz(THz) time-domain spectroscopy. This technique allows for the simultaneous measurement of the amplitude and phase of the transmission coefficient as a function of frequency. The ability to directly measure the phase spectrum is expected to be important in characterizing potential negative index media. In the employed experimental geometry, THz pulses are normally incident on the arrays. Thus, the magnetic field lies in the plane of the arrays and cannot contribute to the magnetic resonance of the SRR. However, it is found that the electric field, when appropriately polarized, can couple to the magnetic resonance. Shifts in the resonance properties with changes in the SRR dimensions and the substrate medium are measured, the results of which are consistent with theory.

Synthesis and Catalytic Activity of a Two-core Ruthenium Carbene Complex: a Unique Catalyst for Ring Closing Metathesis Reaction

The reaction of a ruthenium carbide complex RuCl2（C：）（PCy3）2 with [H（Et2O）x]＋[BF4]- at a molar ratio of 1：2 produced a two-core ruthenium carbene complex, {[RuCl（=CHPCy3）（PCy3）]2（μ-Cl）3}＋·[BF4]-, in the form of a yellow-green crystalline solid in a yield of 94%. This two-core ruthenium complex is a selective catalyst for ring closing metathesis of unsubstituted terminal dienes. More importantly, no isomerized byproduct was observed for N-substrates when the two-core ruthenium complex was used as the catalyst at an elevated temperature（137 °C）, indicating that the complex is a chemo-selective catalyst for ring closing metathesis reactions.

Compact Metamaterial Antenna with High Directivity for Bio-Medical Systems

In this paper, high directive antenna using metamaterial property is presented for wireless medical systems. The antenna is constructed by semi-circular patch and hexagonal closed ring resonator (HCRR). For medical applications such as wireless patient movement monitoring, telemetry and telemedicine, communication devices working at ISM band frequency is needed. Here, the requirement is completed with improved directivity such as 16 dBi. And also impedance matching also achieved with low reflection loss -20 dB. This antenna works for multiple frequency bands (Industrial, Scientific and Medical-ISM 2.45 GHz, WLAN 5.3 GHz and GSM 1.9 GHz) with improved directivity.

An attempted approach to the tricyclic core of haliclonin A：Structural elucidation of the final product by 2D NMR

We describe the design and execution of a novel synthetic route to the tricyclic core of haliclonin A,a tetracyclic marine natural product.The approach features Bachi＇s thiol-medicated free radical cyclization of alkenyl isocyanide to build the bridged ring system,and ring-closing metathesis（RCM） reaction to form the macrocycle.Execution of the synthetic plan ultimately resulted in a diazatricyclic compound.By means of 2D NMR techniques,the structure of this compound was revealed to an unexpected product 8.Analysis of the synthetic pathways allowed concluding that the unexpected product is a result of an ＂unexpected＂ migration of olefinic bond during dioxolanation of the 2-cyclohexenone derivative 7.This investigation also resulted in a concise construction of the functionalized hexahydro-1H-isoindole-1,5（4H）-dione 12 and the macrocyclic tricyclic ring system 8.