Quantum computation has been drawing more and more attentions, since the Shor's algorithm and Grover's algorithm are proposed in the middle 1990s. Among the systems being pursued for physically implementing a quantum computer, the diamond solid-state quantum computation, which use the electronic or nuclear spins of nitrogen-vacancy (NV) centers as qubits, is considered more favorable because it has a super long coherence time at room
temperature and precise manipulations for the system are readily available. In addition, NV centers may be used for single spin detection by magnetic resonance. For NV centers with a distance of tens of nanometers among them, the inter-center force will be strong enough to establish a quantum computer. However, the conventional confocal microscopy can only be used to resolve centers that are more than two hundred nanometers away from each other. Super-resolution microscopy techniques, such as stimulated emission depletion (STED) and ground state depletion (GSD), may provide a way to resolve NV centers with a resolution beyond the diffraction limit. In recent year, super-resolution microscopy has been used in combination with advanced surface processing technology for accurate positioning of NV centers in diamond. In this paper, we briefly summarize the super-resolution microscopy
techniques that have been used in diamond solid-state quantum computation, and reviewed the latest developments in the field.

The design and implementation of a low-temperature liquid level monitor unit used in superconducting magnets is introduced. In the design, voltage-controlled current source circuit and voltage-frequency conversion circuit are used in liquid helium level measurement, and capacitance-frequency conversion circuit is used in liquid nitrogen level measurement. Digital circuit based on STM32 microcontroller is used to control the voltage-controlled current source, process the frequency signal, display the liquid-level data, send the liquid-level data to the upper computer and use CAN bus to complete the remote control of the unit. The feasibility of the design was demonstrated by experimental measurements.

We developed a computer-controlled olfactometer for delivering odors for functional magnetic resonance imaging (fMRI) experiments. The olfactometer is consisted of an air transport system and a control system. Odors are produced and delivered by the air transport system, in which air flow first passes through liquid mixed with odorants in gas-washing bottles and then is delivered to the test subjects. The control system provides a user interface for
operating the device and controlling solenoid valves. The system is based on virtual instrumentation technology, and the software for it is written in LabVIEW. The device was tested on a Siemens 3.0 T MRI scanner. Block-design fMRI data were collected from one healthy subject who was stimulated with two odors, isoamyl acetate and pyridine. The raw fMRI data were processed with Matlab-based SPM8 and MarsBaR toolbox. Region-of-interest (ROI)-based analysis was performed for the left orbitofrontal cortex and left insula. It was found that the signal changes in the two ROIs were basically in compliance with the stimulation paradigm, but the signal changes induced by pyridine were more robust than that produced by isoamyl acetate stimulation. In the same ROI, the signal intensity changes caused by pyridine were higher than that induced by isoamyl acetate.

The goal of the study is to design and construct a system that can be used to detect magnetic resonance signals generated in the stray magnetic field produced by fully-opened unilateral magnets. The radiofrequency (RF) probe was carefully designed to meet the detection depth requirement for specific applications, and tested on a unilateral nuclear magnetic resonance experiment system. The probe had a 90º pulse width as short as 2.5 s. The whole system has a short system dead time (i.e., 10 s), and the minimum half echo time was 15 s. The SGSE-CPMG experiment was performed on the system to acquire signals from a depth of 5 mm under a constant B0 gradient of 15.3 T/m. Diffusion coefficients were measured under the constant B0 gradient.

Although the portable NMR spectrometers usually have lower signal-to-noise (SNR) and resolution compared to superconducting nuclear magnetic resonance (NMR) spectrometers, they show great advantages in more practical applications, such as fast on-site testing. In recent years, the rapid advances in hardware and experimental methods improved portable NMR spectrometers considerably, in terms of both robustness and analysis ability. This paper introduces recent progresses of portable NMR spectrometers in several aspects: hardware and software developments, high-resolution experimental methods, applications, and prospective on their future development.

A method to increase signal-to-noise ratio (SNR) in magnetic resonance imaging using dynamic receiver gain was proposed. In the method, the receiver gain was adjusted dynamically according to amplitude of each echo signal before acquisition. By doing so, the receiver dynamic range could be optimized to improve SNR of each acquisition. To reconstruct the images, a double-precision floating-point arithmetic processing procedure was used to expand the dynamic range of all acquisitions to the same scale. Imaging experiments were conducted using the proposed method on a 1.5 T clinical MRI scanner.
The results showed that the SNR of T1-weighted images could be improved by approximately 10%, compared to the fixed-receiver-gain images. More importantly, the method proposed needs no extra circuits or multiple time-consuming scans. It is concluded that using dynamic receiver gain for each acquisition is an effective way to improve SNR in MR imaging, especially for high-resolution and high-filed imaging applications.

An automatic baseline correction method for nuclear magnetic resonance (NMR) spectra is presented. It is based on improved baseline recognition in peak regions using an iterative moving averaging algorithm, followed by an iterative baseline modeling procedure. The method combines advantages of two baseline correction methods in order to improve baseline modeling in peak regions. A set of baseline anchor points in peak regions are picked during baseline recognition, and utilized for baseline modeling with baseline points. The proposed baseline correction method was shown to perform well on
NMR spectra even when they have a large nonlinear baseline distortion.

To increase the speed of acquisition of two-dimensional solid-state DQ-SQ spectrum, a compressed sensing algorithm which makes use of the self-sparsity of the spectrum to construct under-sampled data. The energy function used in optimization is l₁ norm together with the finite difference term. In the finite different term, we used different weights for the horizontal and vertical finite differences. Different sampling schemes were compared and pseudo-random sampling combined with compressed sensing reconstruction was found to yield the best results. Furthermore, we found that the extreme case of
pseudo-random sampling, that is, t1-cutoff sampling may be the best choice.the best results. Furthermore, we found that the extreme case of pseudo-random sampling, that is, t₁-cutoff sampling may be the best choice.

Mungbean (Vigna radiata) is an important crop that has various beneficial functions such as antioxidant and anti-inflammatory activities. However, the metabolites in mungbean have only been partially identified and quantified in previous studies. In this study, we systematically identified and assigned 48 metabolites in mungbean (Elü No.4) seeds with J-RES, COSY, TOCSY, HSQC, HMBC and 2D NMR spectra. In particular, the composition of raffinose family oligosaccharides in the extracts was determined using DOSY experiments. Most of the metabolites in the extracts were quantified. This study will provide useful information for mungbean metabolomic and nutritional studies.

The chiral recognition of racemic ibuprofen by thiourea was studied using ¹H NMR spectroscopy. It was found that, with the participation of DMAP, excellent
recognition of the enantiomers of ibuprofen by thiourea could be achieved, and the process was not affected by the chiral bisthiourea and DMAP. To evaluate the ability of the chiral bisthiourea/DMAP for enantiomeric determination, several ee. values of ibuprofen samples were determined by ¹H NMR, and the results coincided with the theoretical value.

Phosphatidylcholines (PC) is one of the most important phospholipids in the human and animal serum. It is the major constituent of lipoproteins that play important roles in the transport and metabolism of cholesterol. It was found that the many diseases, such as atherosclerosis, cancer, dementia and so on, were often associated with compositional and structural changes of phospholipids. Therefore, it is of interest to study the composition and structure of phospholipids. Here, small unilamellar vesicles (SUV) formed by PC were studied using 1D and 2D NMR experiments. It was found that there were two different [-N+(CH3)3] signals of PC, indicating that the SUV formed by PC may have a bilayer-spherical structure, not as previously thought to be a mono-layer structure.

The use of oil-mixed drilling fluid application may potentially affect the discovery of oil layer, as well as the results of chromatography or spectrum surface
logging. To study and quantify how the use of oil-mixed drilling fluid would affect the results of logging, high-resolution NMR surface logging while drilling technology was used to measure T₂ spectrum and oil content with different levels of oil added into the drilling fluid. The results indicated that oil-mixed drilling fluid exhibited properties of oil in water, and could not blended with the oil layer. As a result, the T₂ spectrum showed two independent peaks of oil. It is concluded that the oil layer can be identified accurately with the use of oil-mixed drilling fluid. In addition, by using the normalization method or external standard method, it was shown that the oil content of layer oil can be calculated in the drilling fluid. Field experiments were used to confirm the results of laboratory experiments.

A narrow-band voltage controlled oscillator (VCO) circuit for phase-locked frequency multiplier in rubidium atomic clock was designed. A clapp oscillation circuit scheme was used in the design. The design of the VCO was analyzed and optimized by simulation. A true VCO circuit was constructed and tested. The performance specifications of VCO were as following: frequency covering 440~470 MHz, tuning sensitivity 18 MHz/V and second harmonic suppression -15 dBc. The phase-locked frequency multiplication system was found to have a low phase noise meeting the requirement of the miniature rubidium atomic clocks.

The influenza fusion peptide plays a pivotal role in the fusion process of the viral membrane with the host-cell endosomal membrane. Recent success of solving the structure of influenza hemagglutinin fusion peptide has led to a new understanding of the fusion mechanism. Although a few hypotheses have been proposed, it is still of great interest to investigate the structure-function relationship of the fusion peptide. In this paper, the progresses in the field for the last decade is reviewed.