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Continuous wave optically detected magnetic resonance (CW-ODMR) is a practical way to study the sensitivity of the DC magnetic field. However, in large ensemble nitrogen-vacancy (NV) defects, the simultaneous excitation of microwave and laser will deteriorate the parameters of the ODMR spectrum and some unwanted sideband excitations caused by P1 electron spins will also bring challenges to further improve the sensitivity and signal quality. Here, we first achieve the CW-ODMR and acquire DC photon-shot-noise-limited magnetic sensitivity of 12 nT / Hz . Different from the conventional method, we take advantage of pulsed quantum filtering (PQF) technology to eliminate such impacts above and demonstrate a sensitivity of about 1 nT / Hz , which an order of magnitude enhancement over CW-ODMR. We find this method provides simple but effective support for relevant high-sensitivity DC magnetometry and obtains pure resonance signal when using large ensemble NV- defects.

The nitrogen-vacancy (NV) centers in diamond have the advantages of stable triaxial structure, ultra-long electron spin coherence time and simple optical readout at room temperature. A nitrogen atom in the diamond crystal replaces a carbon atom and a vacancy is generated at the adjacent position, forming a point defect in the C3v space group structure. Its ground state and excited state are both spin triplet states. It is the key to achieving efficient preparation of optical initial state and extracting NV color center’s information in the researches of highly sensitive sensing magnetic detection, temperature detection, biological imaging, quantum computing, etc. However, there was no systematic study on relevant parameters of laser for high-concentration NV color center’s samples in previous experimental studies. Based on a high concentration diamond NV ensemble, we use pulsed optical detection magnetic resonance (ODMR) technology to systematically study the relationship among laser initial polarization time, information reading time and laser power, and the influence of laser incident polarization angle on the accuracy of sensing information. The effects of various laser parameters on the NV1 peak of ODMR on the [111] axis of the NVs of diamond are also investigated. The contrast of ODMR increases firstly with a sigmoid function and then decreases with an e-exponential function as the information reading time increases. The incident polarization angle of the laser is sinusoidal, with a period of 90°. According to the above experimental results, we finally choose the appropriate experimental parameters at 45.8 W/cm2 (300 μs of polarization, 700 ns, reading time, laser incident angle is 220°) for ODMR test. Compared with previous experimental parameters (polarization time was 50 us, read the time of 3000 ns, laser incident angle was 250°), the experimental results show that the contrast of ODMR increases from 2.1% to 4.6%, and the typical magnetic sensitivity is improved from 21.6 nT/Hz1/2 to 5.6 nT/Hz1/2. The optimization of the optical control of NVs in solid diamond is realized. The above results provide an effective support for the detection of high-sensitivity manipulation sensing based on high-concentration NV ensemble.

Case-based reasoning system (CBR) has been widely applied to the issue of market segmentation. Most of previous studies focused on dividing customers into two groups. Consequently, traditional voting method used for two groups in CBR would become inappropriate when one would like to divide customers into three groups through some segmentation variable. In this paper, a new voting method called 3NN+1 is proposed to bridge the gap. To make the inference of the 3NN+1 based CBR system more efficient, the features and instances (or cases) for reasoning is selected simultaneously by means of genetic algorithms. This new system is applied to a real case of notebook market to demonstrate its usefulness for market segmentation. From the results of the real case, it shows that the system would be valuable to enterprises, when dividing customers into three groups in compliance with their purchasing behaviors for developing marketing strategies.

One new diferrocene Schiff base was prepared by condensing 1′-formyl[(2,2-diferrocenyl)propane] with isonictinoyl hydrazine. 1′-formyl[(2,2-diferrocenyl)propane]isonicotinoyl hydrazone (HL) and its chelates with lanthanide ions, Ln(HL) 2 Cl 3 (H 2 O) n (Ln=La, Dy, Yb, Gd, Sm, Nd; n =1–5.) were prepared, isolated and characterized by elemental analysis, IR and 1 H NMR spectra. In these chelates the ligand coordinates to lanthanide ions in the keto form, and some chloride ions and water molecules participate in coordination to the metal ion. The redox properties of the ligand and its complexes were investigated using cyclic voltammetric method. Both the ligand and its lanthanide complexes exhibit two distinct pairs of redox peaks displaying electrochemical characteristics of multi-component system.

Complexes of the type [(3-Fc, 5-Me)Pz]n'MCl2 [Fc = ferrocenyl, Pz = pyrazole, M = Zn(II), Cd(II) and n = 1 or 2] have been synthesized and characterized by elemental analyses, IR, 1H NMR spectra and cyclic voltammetry Elemental analyses reveal a ligand to metal ratio of 1. 1 for Cd(II) and 2 : 1 for Zn(II). No satisfactory elemental analysis results were obtained for the Hg(II) complex due to possible decomposition of the ligand.

Eight new emodin derivatives that contain large conjugative system have been synthesized and their anticancer activities also have been evaluated. The result shows that large conjugative system can not enhance the anticancer activities of emodin derivatives, but the introduction of an alkylating center can make emodin derivative effective against cancer cell lines. Compound 12 has the highest alkylating ability, but its anticancer activity is not remarkable, which indicates that there is not a direct correlation between the chemical reactivity of the alkylating agent and the toxic effects.