A CVD diamond film detector for pulsed proton detection

A chemical vapour deposition （CVD） diamond film detector was prepared and the main characteristics for pulsed proton detection were studied at Beijing Tandem Accelerator. The result shows that the charge collection efficiency of the detector increases with increasing electric field intensity and reaches to 9.44% at 5 V/μm with the charge collection distance of 15.9 μm. The relationship between the sensitivity of the detector and proton energy is consistent with the Monte Carlo （MC） simulation result. Its plasma time for a pulse with 4.85×10^5 protons is 1l.2ns. The dose threshold for onset of damage under 9MeV proton irradiation in the detector is about 10^13 cm^-2. All of the results show that a CVD diamond detector has fast time response and high radiation hardness, and can be used in pulsed proton detection.

A Method of Peak Detecting for Nanosecond Pulse in Optical Performance Monitoring System

In optical performance monitoring system,the analog to digital converter is needed to detect the peak of nanosecond pulse and get the signal envelope.A scheme based on a designed anti-aliasing filter and analog to digital converter is proposed to broaden the nanosecond pulse and make it easier for the analog to digital converter to catch the peak of the nanosecond pulse.The experimental results demonstrate that,with the proposed scheme,the optical performance system needs less time to get the recovered eye-diagram of high speed optical data signal,and is robust to phase mismatch in the analog to digital converter circuit.

Determination of neomycin in water samples by high performance anion chromatography with pulsed amperometric detection

A simple, fast and reliable method, using high performance anion chromatography with pulsed amperometric detection, had been developed for the analysis of neomycin in water samples. The elution and separation were carried out with an isocratic mobile phase, containing 10 mmol/L NaOH. The influence of the concentration and pH of the mobile phase on the separation and detection was investigated. A quadruple-potential waveform used for the detection was optimized. The detection limit of neomycin was down to 0.027 μg/mL. The linearity of neomycin calibration curve ranged from 0.050 to 0.505 μg/mL with correlation coefficient of 0.9997. R.S.D. (n = 11) was 4.0%.

Deterministic Quantum Key Distribution with Pulsed Homodyne Detection

In this paper, we propose a deterministic quantum communication protocol using weak coherent states and pulsed homodyne detection. In this protocol, the communication parties exchange their secret information deterministicaJly in two rounds. The devices and efficiency of the protocol are discussed respectively. We also show the security of the protocol against intercept-resend and Trojan-Horse eavesdropping attacks.

A study of the strong pulses detected from PSR B0656+14 using the Urumqi 25-m radio telescope at 1540 MHz

We report on the properties of strong pulses from PSR B0656＋14 by analyzing the data obtained using the Urumqi 25-m radio telescope at 1540 MHz from August 2007 to September 2010.In 44 h of observational data,a total of 67 pulses with signal-to-noise ratios above a 5σthreshold were detected.The peak flux densities of these pulses are 58 to 194 times that of the average profile,and their pulse energies are 3 to 68 times that of the average pulse.These pulses are clustered around phases about 5-ahead of the peak of the average profile.Compared with the width of the average profile,they are relatively narrow,with the full widths at half-maximum ranging from 0.28 ° to 1.78 °.The distribution of pulse-energies follows a lognormal distribution.These sporadic strong pulses detected from PSR B0656＋14 have different characteristics from both typical giant pulses and its regular pulses.

A digital transmission system for high intensity pulsed radial detection

A digital transmission system with 900 MHz bandwidth and over 40 dB linear dynamic range for high intensity pulsed radial detection is designed. The transient signals （with a subnanoseconds rising edge） from the detectors can be transmitted to diagnosing systems kilometers away with high fidelity. It can adapt to interference and a hostile detecting environment by using the intelligent functions of this system. The feasibility and reliability of this system is verified by system evaluation tests.

Optimizing the Quadruple-potential Waveform for the Determination of Gentamicin Sulfate by High Performance Liquid Chromatography with Pulsed Electrochemical Detection

In this paper, a quadruple-potential waveform was investigated and optimized for the determination of gentamicin by reversed phase ion-pair chromatography. Instead of a relatively high positive potential, a negative potential was adopted as a potential for the cleaning of gold working electrode. By this way, the formation of gold oxide resulting from the application of high positive potential during the analyte detection and electrode cleaning was greatly reduced, and therefore, the dissolution and recession of gold working electrode was also reduced. The good condition of gold working electrode achieved by this quadruple-potential waveform can help us to obtain a good reproducibility. In order to acquire signal-to-noise ratio as high as possible, several waveform parameters affecting the detection of gentamicin were carefully selected. The analytical method has been applied to the determination of two real gentamicin samples, and good results with low relative standard deviation not more than 4% were obtained.

An early screening model of pulse detection technology for hepatic steatosis

Background The increasing prevalence of hepatic steatosis presents a considerable challenge to public health.There is a critical need for the development of novel preventive and screening strategies for this condition.Thisstudy evaluated the potential applications of wrist pulse detection technology for the early detection of liverdiseases.The pulse time-domain features of a medical exam population with and without hepatic steatosis wereassessed to develop a screening model for this disease.Methods Participants were consecutively recruited from March 2021 to March 2022 in the medical examinationcenters of the Yueyang Hospital of Integrated Traditional Chinese and Western Medicine and the Shanghai Municipal Hospital of Traditional Chinese Medicine.Clinical data from 255 participants,including general information(sex,age,and body mass index),and data related to glucose and blood lipids(fasting plasma glucose,triglyceride,total cholesterol,high-density lipoprotein,and low-density lipoprotein levels)were collected.Wrist pulse signalswere acquired using a pulse detection device,and the pulse time-domain features,including t_(1),t_(4),t_(5),T,w_(1),w_(2),h_(2)/h_(1),h_(3)/h_(1),and h5/h_(1) were extracted.Participants were assigned to hepatic steatosis and non-hepatic steatosisgroups according to their abdominal ultrasound examination results.Their clinical data and pulse time-domainfeatures were compared using chi-square and parametric or non-parametric statistical methods.Three datasetswere used to construct screening models for hepatic steatosis based on the random forest algorithm.The datasetsfor modeling were defined as Dataset 1,containing blood glucose and lipid data and general information;Dataset2,containing time-domain features and general information;Dataset 3,containing time-domain features,bloodglucose and lipid data,and general information.The evaluation metrics,accuracy,precision,recall,F1-score,andareas under the receiver operating characteristic curve(AUC)were compared for each model.Results The time-domain features of the two groups differed significantly.The t_(1),t_(4),t_(5),T,h_(2)/h_(1),h_(3)/h_(1),w_(1),and w_(2) features were higher in the hepatic steatosis group than in the non-hepatic steatosis group(P<0.05),while the h5/h_(1) features were lower in the hepatic steatosis group than in the non-hepatic steatosis group(P<0.05).The screening models for hepatic steatosis based on both time-domain features and blood glucose andlipid data outperformed those based on time-domain features or blood markers alone.The accuracy,precision,recall,F1-score,and AUC of the combined model were 81.18%,80.56%,76.32%,79%,and 87.79%,respectively.These proportions were 1.57%,1.86%,1.76%,2%,and 3.54%higher,respectively,than those of the model basedon time-domain features alone and 3.14%,4.2%,2.64%,4%,and 6.47%higher,respectively,than those of themodel based on blood glucose and lipid alone.Conclusion The early screening model for hepatic steatosis using datasets that included pulse time-domainfeatures achieved better performance.The findings suggest that pulse detection technology could be used toinform the development of a mobile medical device or remote home monitoring system to test for hepatitissteatosis.

Combination of differential discrimination and direct discrimination in pulsed laser timeof-flight systems

The output amplitude of the differential circuit is studied for differential discrimination in pulsed laser time-offlight systems. Based on the studies of the probability of detection and the probability of false alarms, the minimum detectable input signal of differential discrimination can be calculated. The results indicate that the differential discrimination detectability of the small signal will be reduced. A combined discrimination is proposed in this Letter to improve the time resolution of the large signal and ensure the probability of detection of the small signal at the same time. A proper value of the circuit parameter is found to balance the time resolutions of the small and large signals.

Theoretical analysis and numerical solution of laser pulse transformation for satellite laser ranging

The processes of the pulse transformation in satellite laser ranging (SLR) are analyzed,the analytical expressions of the transformation are deduced,and the effects of the transformation on Center-of-Mass corrections of satellite and ranging precision are discussed.The numerical solution of the transformation and its effects are also given.The results reveal the rules of pulse transformation affected by different kinds of factors.These are significant for designing the SLR system with millimeter accuracy.

New organic scintillation fiber detector for the measurement of intense pulsed fission neutron

To measure the pulsed neutron of a pulsed fission source, an organic scintillation fiber （OSF） detector with separation structure has been designed. The proposed detector employs UV optical fibers as the light guide, and the sensitive region of the detector is composed of a linear array of OSFs, which are individually connected to the optical fibers. The other end of the light guide is coupled to a photomultiplier tube. The key properties of the device including the energy response, time response, neutron sensitivity, and radiation effect of the optical fiber were studied. The detector has a relatively high n/γ sensitivity ratio, which increases as the diameter of the OSF decreases, and ratios greater than 10 could be achieved when the diameter of the OSF is less than 0.3 nun. The sensitivity of the detector to neutrons ranges from 10-14 to 10-20 C cm2/n, and has a response time of 3 ns （FWHM）. The proposed detector is also highly flexible. For instance, the probe can be set close to the source, while the PMT can be placed far away from radiation, allowing easy shielding. Due to these characteristics, pulsed fission neutrons in the vicinity of the source can be accurately measured.

A proposed approach for detecting terahertz pulses by using double few-cycle laser pulses with opposite carrier envelope phases

Previous research shows that few-cycle laser（FCL） pulses with low energy and without a bias field can be used to coherently detect terahertz（THz） pulses. As we know, it is very difficult to stabilize the carrier envelope phase（CEP） of FCL pulses, i.e., there are some random fluctuations for the CEP. Here we theoretically investigate the influence of such instability on the accuracy of THz detection. Our results show that although there is an optimum CEP for THz detection, the fluctuations of the CEP will lead to terrible thorns on the detected THz waveform. In order to solve this problem, we propose an approach using two few-cycle laser pulses with opposite CEPs, i.e., their CEPs are differed by π.