Research on the Drawing-up of the Pole Figure for Orientation Analysis of Directional Si Steel Sheet

The magnetic property of soft magnetic metals and alloys depends strongly on the crystallo-graphic orientation. In automated equipment for orientation research, the intensity for drawing up the pole figure is measured in detail. The present research shows that the accurate pole figure can be drawn up without measuring concretely the intensity. For directional Si steel sheet the measuring step may be 4～5 degrees. In this paper the experimental equation for defo-cusing correction was derived from the experimental data in different specimens with random orientation.

Directional Analysis of the Chaotic Superlattice around the Equilibrium Point in the Phase Space

The recently proposed method of our research group named as directional Lyapunov exponents（DLEs） is presented. Then, DLEs are used to analyze the eigenstructure of the output phase space around the equilibrium points. Finally, the impacts of the superlattice parameter changes on the characteristics of the output chaotic signal are analyzed. The experimental results show that parameter changes of the superlattice will affect the eigenstructure around the equilibrium points in the output phase space, and DLEs are sensitive to these changes.

Emerging frontier technologies for food safety analysis and risk assessment

Access to security and safe food is a basic human necessity and essential for a sustainable world. To perform hi-end rood safety analysis and risk assessment with state of the art technologies is of utmost importance thereof. With applications as exemplified by microfiuidic immunoassay, aptasensor, direct analysis in real time, high resolution mass spectrometry, benchmark dose and chemical specific adjustment factor, this review presents frontier food safety analysis and risk assessment technologies, from which both food quality and public health will benefit undoubtedly in a foreseeable future.

Analysis of Peanut Oil Adulterated with Other Edible Oils by Spectrophotometry

Since peanut oil（PO） is more expensive than other seed oils, some PO is adulterated with other cheap seed oils, such as soybean oil, palm olein, cottonseed oil, corn oil and rapeseed oil. The conventional method for deter mining whether PO was adulterated is to detect the freezing point of oils. The proposed method for the determination of adulterants in PO was based on monitoring the change of absorbance when the sample was refrigerated. A special spectrophotometer was developed. A total of 10 kinds of POs from different suppliers were chosen and adulterated with other seed oils at the volume fraction levels ranging from 5% to 30%. A total of 150 samples were analyzed by the proposed method and the results were satisfactory.

The Security Analysis of Two-Step Quantum Direct Communication Protocol in Collective-Rotation Noise Channel

To analyze the security of two-step quantum direct communication protocol （QDCP） by using Einstein-Podolsky Rosen pair proposed by Deng et al. [Phys. Rev. A 68 （2003）042317] in collective-rotation noise channel, an excellent model of noise analysis is proposed. In the security analysis, the method of the entropy theory is introduced, and is compared with QDCP, an error rate point Qo（M ： （Q0, 1.0）） is given. In different noise levels, if Eve wants to obtain the same amount of information, the error rate Q is distinguishable. The larger the noise level ~ is, the larger the error rate Q is. When the noise level ~ is lower than 11%, the high error rate is 0.153 without eavesdropping. Lastly, the security of the proposed protocol is discussed. It turns out that the quantum channel will be safe when Q 〈 0.153. Similarly, if error rate Q〉 0.153 = Q0, eavesdropping information I 〉 1, which means that there exist eavesdroppers in the quantum channel, and the quantum channel will not be safe anymore.

Observations and Estimations of Directional Spectrum of Sea Waves

The directional spectrum is one of the basic characteristics of sea waves. The observations of directional spectrum of sea waves were successfully conducted at platform Bohai 8 during 1991 and 1992 using a wave gage array for the first time in China. Based on the field data, the directional spectrum which depends on the wave growth is given in this paper. Before observations, the effects of the type of gage array, the distance between the gages and the platform itself on the measured results and the precision of some methods for estimating the directional spectrum were investigated and compared with the methods of numerical simulations and model tests of multi-direcitonal irregular waves. This ensures the quality of the observations and estimations of the directional spectrum.

Improving RNA secondary structure prediction using direct coupling analysis

Secondary structures of RNAs are the basis of understanding their tertiary structures and functions and so their predictions are widely needed due to increasing discovery of noncoding RNAs.In the last decades,a lot of methods have been proposed to predict RNA secondary structures but their accuracies encountered bottleneck.Here we present a method for RNA secondary structure prediction using direct coupling analysis and a remove-and-expand algorithm that shows better performance than four existing popular multiple-sequence methods.We further show that the results can also be used to improve the prediction accuracy of the single-sequence methods.

FIXED/PREASSIGNED-TIME SYNCHRONIZATION OF QUATERNION-VALUED NEURAL NETWORKS INVOLVING DELAYS AND DISCONTINUOUS ACTIVATIONS: A DIRECT APPROACH

The fixed-time synchronization and preassigned-time synchronization are investigated for a class of quaternion-valued neural networks with time-varying delays and discontinuous activation functions. Unlike previous efforts that employed separation analysis and the real-valued control design, based on the quaternion-valued signum function and several related properties, a direct analytical method is proposed here and the quaternion-valued controllers are designed in order to discuss the fixed-time synchronization for the relevant quaternion-valued neural networks. In addition, the preassigned-time synchronization is investigated based on a quaternion-valued control design, where the synchronization time is preassigned and the control gains are finite. Compared with existing results, the direct method without separation developed in this article is beneficial in terms of simplifying theoretical analysis, and the proposed quaternion-valued control schemes are simpler and more effective than the traditional design, which adds four real-valued controllers. Finally, two numerical examples are given in order to support the theoretical results.

Analysis of Nonlinear Directional Couplers

1 IntroductionSince the coupled-mode theory in cylindrical optical-fiber systems was proposed in 1972, the optical coupling between parallel optical waveguides has been a matter of scientific concern. Two-core fiber couplers, especially, have been studied extensively since the success of producing a two-core fiber functioning as a directional coupler in 1980. The wavelength and polarization selectivity of two-core fibers can find many applications. The nonlinear properties of the two-core fiber coupler ...

Electron acceleration by tightly focused radially polarized few-cycle laser pulses

Within the framework of plane-wave angular spectrum analysis of the electromagnetic field structure, a solution valid for tightly focused radially polarized few-cycle laser pulses propagating in vacuum is presented. The resulting field distribution is significantly different from that based on the paraxial approximation for pulses with either small or large beam diameters. We compare the electron accelerations obtained with the two solutions and find that the energy gain obtained with our new solution is usually much larger than that with the paraxial approximation solution.

DIRECT DIGITAL DESIGN AND SIMULATION OF MESHING IN WORM-GEAR DRIVE

A direct digital design method （DDDM） of worm-gear drive is proposed. It is directly based on the simulation of manufacturing process and completely different from the conventional modeling method. The loaded tooth contact analysis （LTCA） method is analyzed, in which the advanced surface to surface searching technique is included. The influence of misalignment errors and contact deformations on contact zone and transmission error （TE） is discussed. Combined modification approach on worm tooth surface is presented. By means of DDDM and LTCA, it is very conven- ient to verify the effect of worm-gear drive＇s modification approach. The analysis results show that, the modification in profile direction reduces the sensitivity of worm-gear drive to misalignment errors and the modification in longitudinal direction decreases the TE. Thus the optimization design of worm-gear drive can be achieved prior to the actual manufacturing process.

Design and Analysis of Compact Directionally Coupled Bistable Laser Diodes

A compact optical flip-flop with a directional coupler has been designed and analyzed. Using a narrow gap directional coupler, we have predicted the device length could be reduced down to 500μm from 1300μm.

Methods and applications of RNA contact prediction

The RNA tertiary structure is essential to understanding the function and biological processes. Unfortunately, it is still challenging to determine the large RNA structure from direct experimentation or computational modeling. One promising approach is first to predict the tertiary contacts and then use the contacts as constraints to model the structure. The RNA structure modeling depends on the contact prediction accuracy. Although many contact prediction methods have been developed in the protein field, there are only several contact prediction methods in the RNA field at present. Here, we first review the theoretical basis and test the performances of recent RNA contact prediction methods for tertiary structure and complex modeling problems. Then, we summarize the advantages and limitations of these RNA contact prediction methods. We suggest some future directions for this rapidly expanding field in the last.

Perspectives on Everyday Suffering among People with Adult Attention Deficit Hyperactivity Disorder and Concurrent Mental Disorders

The aim of this study was to describe the perceptions of everyday suffering among adults with attention deficit hyperactivity disorder (ADHD) and comorbid mental disease. Directed content analysis guided by Eriksson’s theory on human suffering was performed on data from 20 individual interviews. Expressions of both suffering and well-being were identified;the former centred on loneliness and related to life, illness, and care, which supported Eriksson’s theory, whereas expressions of well-being related to ADHD diagnosis and supportive social relationships. Nevertheless, results indicate the need to expand those expressions in order to better contribute to developing a supportive rehabilitation regimen that can provide more interpersonal care.

A direct coupling analysis method and its application to the Scientific Research and Demonstration Platform

Design of a very large floating structure(VLFS)deployed near islands and reefs,different from those in the open sea,inevitably faces new technical challenges including numerical analysis methods.In this paper,a direct coupling analysis method(DCAM)has been established based on the Boussinesq equations and the three-dimensional hydroelasisity theory with Rankine source method to analyze the responses of a VLFS in shallow sea with complicated geographical environment.Model tests have been carried out to validate the DCAM.To further verify the numerical methods and investigate the performance of such a VLFS,a“Scientific Research and Demonstration Platform(SRDP)”was built and deployed in 2019 at the site about 1000 m off an island with water depth around 40m in South China Sea.It is a simplified small model of a two-module semi-submersible-type VLFS.The numerical simulation of its responses on severe waves with focus on motions and connector forces is conduct by DCAM,and compared with the on-site measurements.Good agreement has been achieved.This approves the DCAM as a feasible tool for design and safety assessment of a VLFS deployed near islands and reefs.

New Strategy for Further Improving the Detection Sensitivity of Direct Analysis in Real Time-Mass Spectrometry

Ambient mass spectrometry facilitates surface detection under ambient conditions and has quickly found its applications in various areas.However,the sensitivity of AMS methods is usually not as good as that of encapsulated ion sources due to less efficient ion transmission.In this work,a briefly machined external ion funnel(threepole electrostatic lens)was adopted and installed between direct analysis in real time and the mass spectrometer inlet to increase detection sensitivity.Software investigation with SIMION version 8.0 was employed to calculate electric fields and to simulate the trajectories of charged particles in the electric field.Both the geometrical parameters of the ion funnel and the electric parameters were studied to obtain the optimal ion focusing results,which demonstrated the ion funnel equipment would greatly improve the ion transmission efficiency.The equipment showed good prospect in direct analysis in real time-mass spectrometry analysis in the future.

Application of Spectra Accuracy for Analysis of Organic Explosive: 2,4,6‑trinitrotoluene by AccuTOF‑DART

This paper,through mass spectrometric(MS)analysis for nitro compound explosives on a direct analysis in a real‑time time‑of‑flight MS,indicates that even on a high‑resolution MS with accurate mass measurement capabilities,there is no guarantee to obtain the unique molecular formula of a compound.By calculating spectra accuracy,highly accurate isotope pattern matching can be conducted to significantly improve performance of compound confirmation or identification.

Combination of Solid-Phase Micro-Extraction and Direct Analysis in Real Time-Fourier Transform Ion Cyclotron Resonance Mass Spectrometry for Sensitive and Rapid Analysis of 15 Phthalate Plasticizers in Beverages

A method for rapid identification and quantification of phthalate plasticizers in beverages was developed.A number of 15 phthalate plasticizers which covered all the phthalates concerned in the US Consumer Product Safety Improvement Act(CPSIA),European Union legislations and Chinese national standards(GB)were analyzed.By a combined solid-phase micro-extraction(SPME)and direct analysis in real time mass spectrometry(DART-MS)approach,phthalates at sub-ng•mL^(−1)levels can be qualitatively and quantitatively analyzed in a short time.The use of ultrahigh-resolving power and the accurate mass measurement capacity naturally provided by Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR-MS)minimizes the matrix interferences and thus enables the evaluation of phthalates in a complex matrix without extensive sample handlings or preparations.The limits of quantification(LOQs)were estimated to be at 0.3-5.0 ng•mL^(−1),lower than the Maximum Residue Limit(MRL)regulated by the European Union legislations(2007/19/EC)in foods,beverages,food packaging and toys(0.3-30 ng•mL^(−1)).This rapid and easy-to-use SPME-DART-FT-ICR-MS method provided a relatively high-throughput and powerful analytical approach for quick testing and screening phthalates in beverages and water samples to ensure food safety.

Direct analysis method of^(14)C radioactivity concentration in urine samples

Objective:To establish a rapid analysis method for the activity concentration of carbon-14(14C)in urine,in order to estimate the internal dose of 14C exposure,and to protect the health of occupational population.Methods:Liquid scintillation counting(LSC)combined with the function of transformed spectral index of the external standard spectrum(tSIE)was used to measure the quenching level and counting rate,and the spiked urine samples with different shades of color were measured by LSC.After establishing the efficiency-quenching curve,the quenching correction and activity concentration analysis of the actual samples were carried out.Results:By LSC and the data fitting,the relationship between efficiency and quenching index could be represented using the equation y=0.0013x-0.0177(R^(2)=0.978).Three actual spiked samples were tested to verify this method,with recoveries of 97%,102%,and 89%,respectively.14C activity concentration of 4 actual urine samples were 0.12,0.11,0.10 and 0.08 Bq/mL,respectively,while the corresponding extended relative uncertainties were 0.0652,0.0929,0.0893 and 0.1043,respectively.Conclusion:The direct analysis method of 14C activity concentration in urine samples was established using LSC.The recovery of 14C activity concentration in urine samples showed that the proposed method had relatively high accuracy.By studying on the source of uncertainty,the uncertainty of the analysis results mainly came from the statistical error of LSC,and the uncertainty component of counting efficiency.

DART-MS:A New Research Tool for Herbal Medicine Analysis

Direct analysis in real time(DART) possesses the merits of analyzing sample in its native status with minimal or even no sample pretreatment.In this review, we summarized the recent applications of DART in the field of herbal medicine analysis such as compound detection, species identification, metabolites profiling and initial quantification. DART with the characters of hyper-rapid, easy-hyphenated offers a new research tool for herbal medicines to complete the experimental process in a very simple but still reliable way. It is anticipated that more wide and deep applications of DART in herbal medicine analysis, as rapid quantification, high-throughput active compounds screening, rapid species identification, and fast illegal additives screening will be promising and foreseeable in the near future.