A Microwave Field-Induced Nonlinear Metamaterial with Wafer Integration Level.

Field-induced nonlinear materials, with extended abilities of manipulating electromagnetic waves, have been widely employed in electromagnetic protection, absorption, and detection. Until now, it was found that the field-induced nonlinearity mainly shows in the optical and terahertz frequency bands. Applying the microwave band into such technical activities is hampered due to a lack of investigations on the nonlinearity caused by microwave electric fields, especially in the ultrawideband and microwave high-frequency bands. In this paper, a nonlinear metamaterial (NLMM) concept based on the integration of metamaterial structures and a semiconductor on the same wafer is proposed, which shows nonlinear behavior to the electromagnetics' field energy in the microwave band. The designed NLMM is transparent to low-density electromagnetic radiation fields, while it adaptively becomes opaque to high-density electromagnetic radiation fields. Two types of NLMM are designed to verify the nonlinear characteristics of ultrawide and narrow bands in the microwave band, respectively. The concept of NLMM can be used for the application of the microwave frequency band in electromagnetic protection and detection.

2-Cyano-N'-(5-hy-droxy-2-nitro-benzyl-idene)acetohydrazide monohydrate.

The title compound, C(10)H(8)N(4)O(4)·H(2)O, was obtained by the reaction of 5-hy-droxy-2-nitro-benzaldehyde with cyano-acetohydrazide in methanol. The non-H atoms of the hydrazone molecule are approximately coplanar, with a mean deviation from the least-squares plane of 0.056 Å. In the crystal, mol-ecules are linked by N-H⋯O, O-H⋯N and O-H⋯O hydrogen bonds, generating a three-dimensional network.