Delay Effect on Coherent Transfer of Optical Frequency Based on a Triple-Pass Scheme

We demonstrate a triple-pass scheme for coherent transfer of optical frequency and the delay effect on the fiber phase noise compensation. It is theoretically proved that the delay effect consists of both fiber delay and servo delay. The delay effect confines the servo bandwidth within 1/8 and induces a residual fiber phase noise after noise compensation. For a 25-km-long fiber, the servo bandwidth is found to be around 1 k Hz, and the fiber phase noise is suppressed approaching to the theoretical limitation. The triple-pass scheme enables the simultaneous transfer of optical frequency to multiple remote users. The performance of noise compensator in the triple-pass scheme can achieve a similar level result compared with that in the double-pass scheme.

Time delay in InGaN multiple quantum well laser diodes at room temperature

This paper reports that a long delay between the beginning of pumping current pulse and the onset of optical pulse is observed in InGaN laser diodes. The delay time decreases as the pumping current increases, and the speed of the delay time reduction becomes slower as the current amplitude increases further. Such delay phenomena are remarkably less serious in laser diodes grown on GaN substrate than those on sapphire. It attributes the delay to the traps which cause a large optical loss by saturable absorption and retard the laser action. The traps can be bleached by capturing injected carriers. The effect of GaAs laser irradiation on InGaN laser action demonstrates that the traps responsible for the delay are deep centres which can be filled by the photo-assisted processes.

Single Exposure to Antidepressants during Infancy Is Associated with Delayed Behavioral Changes in C57BL/6 Mice

As serotoninergic transmission plays a crucial role in higher brain function in mammals, the disturbance of this system will likely have significant effects on emotion and cognition. Previous studies have reported that chronic treatment with Specific Serotonin Reuptake Inhibitors (SSRIs) during both late pregnancy and lactation was associated with abnormal behavior in adult rats. These data imply that disturbances in serotoninergic transmission during neurodevelopment may have negative effects on both the structure and function of the resultant adult brain. Therefore, the effect of a single exposure to an SSRI or a tricyclic antidepressant that preferentially inhibits serotonin reuptake during the pre-weaning period was examined in adult mice. An oral infusion of paroxetine (70 mg/kg), fluvoxamine (250 mg/kg), clomipramine (180 mg/kg), or saline was administered on postnatal day 14. Starting at 11 weeks of age, mice were assessed using a comprehensive behavioral test battery. Mice treated with paroxetine demonstrated altered behavior on the open field and hole-board tasks;those treated with fluvoxamine had behavioral changes on the light-dark box, hole-board, and sucrose preference tasks, while alteration in forced swimming and cued fear behavior were noted in mice treated with clomipramine. These results suggest that even a single administration of an antidepressant could have profound effects on behavior in adulthood, although the effects might differ dependent on the specific drug that was administered.

The vitiation effects of water vapor and carbon dioxide on the autoignition characteristics of kerosene

In ground tests of hypersonic scramjet, the highenthalpy airstream produced by burning hydrocarbon fuels often contains contaminants of water vapor and carbon dioxide. The contaminants may change the ignition characteristics of fuels between ground tests and real flights. In order to properly assess the influence of the contaminants on ignition characteristics of hydrocarbon fuels, the effect of water vapor and carbon dioxide on the ignition delay times of China RP-3 kerosene was studied behind reflected shock waves in a preheated shock tube. Experiments were conducted over a wider temperature range of 800-1 500 K, at a pressure of 0.3 MPa, equivalence ratios of 0.5 and 1, and oxygen concentration of 20%. Ignition delay times were determined from the onset of the excited radical OH emission together with the pressure profile. Ignition delay times were measured for four cases： （1） clean gas, （2） gas vitiated with 10% and 20% water vapor in mole, （3） gas vitiated with 10% carbon dioxide in mole, and （4） gas vitiated with 10% water vapor and 10% carbon dioxide, 20% water vapor and 10% carbon dioxide in mole. The results show that carbon dioxide produces an inhibiting effect at temperatures below 1 300 K when Ф = 0.5, whereas water vapor appears to accelerate the ignition process below a critical temperature of about 1 000 K when Ф = 0.5. When both water vapor and carbon dioxide exist together, a minor inhibiting effect is observed at Ф = 0.5, while no effect is found at Ф = 1.0. The results are also discussed preliminary by considering both the combustion reaction mechanism and the thermophysics properties of the fuel mixtures. The current measurements demonstrate vitiation effects of water vapor and carbon dioxide on the autoignition characteristics of China RP-3 kerosene at air-like O2 concentration. It is important to account for such effects when data are extrapolated from ground testing to real flight conditions.

Considering the Fault Dependency Concept with Debugging Time Lag in Software Reliability Growth Modeling Using a Power Function of Testing Time

Since the early 1970s tremendous growth has been seen in the research of software reliability growth modeling. In general, software reliability growth models （SRGMs） are applicable to the late stages of testing in software development and they can provide useful information about how to improve the reliability of software products. A number of SRGMs have been proposed in the literature to represent time-dependent fault identification / removal phenomenon; still new models are being proposed that could fit a greater number of reliability growth curves. Often, it is assumed that detected faults are immediately corrected when mathematical models are developed. This assumption may not be realistic in practice because the time to remove a detected fault depends on the complexity of the fault, the skill and experience of the personnel, the size of the debugging team, the technique, and so on. Thus, the detected fault need not be immediately removed, and it may lag the fault detection process by a delay effect factor. In this paper, we first review how different software reliability growth models have been developed, where fault detection process is dependent not only on the number of residual fault content but also on the testing time, and see how these models can be reinterpreted as the delayed fault detection model by using a delay effect factor. Based on the power function of the testing time concept, we propose four new SRGMs that assume the presence of two types of faults in the software： leading and dependent faults. Leading faults are those that can be removed upon a failure being observed. However, dependent faults are masked by leading faults and can only be removed after the corresponding leading fault has been removed with a debugging time lag. These models have been tested on real software error data to show its goodness of fit, predictive validity and applicability.

宽带相控阵天线波束指向频响分析和实时延迟器应用

分析了直线和平面宽带相控阵天线扫描波束指向随工作频率改变而产生漂移的现象,给出了阵列单元或子阵采用实时延迟器后,这种指向漂移得以改善的估计。结果表明,漂移为原先的1/M(M为子阵列)。

Drought trend analysis in a semi-arid area of Iraq based on Normalized Difference Vegetation Index, Normalized Difference Water Index and Standardized Precipitation Index

Drought was a severe recurring phenomenon in Iraq over the past two decades due to climate change despite the fact that Iraq has been one of the most water-rich countries in the Middle East in the past.The Iraqi Kurdistan Region(IKR)is located in the north of Iraq,which has also suffered from extreme drought.In this study,the drought severity status in Sulaimaniyah Province,one of four provinces of the IKR,was investigated for the years from 1998 to 2017.Thus,Landsat time series dataset,including 40 images,were downloaded and used in this study.The Normalized Difference Vegetation Index(NDVI)and the Normalized Difference Water Index(NDWI)were utilized as spectral-based drought indices and the Standardized Precipitation Index(SPI)was employed as a meteorological-based drought index,to assess the drought severity and analyse the changes of vegetative cover and water bodies.The study area experienced precipitation deficiency and severe drought in 1999,2000,2008,2009,and 2012.Study findings also revealed a drop in the vegetative cover by 33.3%in the year 2000.Furthermore,the most significant shrinkage in water bodies was observed in the Lake Darbandikhan(LDK),which lost 40.5%of its total surface area in 2009.The statistical analyses revealed that precipitation was significantly positively correlated with the SPI and the surface area of the LDK(correlation coefficients of 0.92 and 0.72,respectively).The relationship between SPI and NDVI-based vegetation cover was positive but not significant.Low precipitation did not always correspond to vegetative drought;the delay of the effect of precipitation on NDVI was one year.

子阵级应用延迟线对相控阵天线带宽改善的分析

采用频率无关移相器的相控阵天线的波束指向会随频率发生变化,实时延迟线是提高宽带相控阵天线指向精度的重要方法。分析了平面相控阵天线波束指向随频率改变而产生漂移的现象,理论分析和仿真结果均表明,当频率改变时,平面相控阵天线的波束指向仅在俯仰角面发生漂移,而在方位角的指向不变。详细讨论采用子阵分割技术,并在子阵级别用实时延迟线,单元内采用移相器的混合波束控制技术。结果表明,这种方法可以有效扩展相控阵天线的带宽。

Highly efficient hybrid warm white organic light-emitting diodes using a blue thermally activated delayed fluorescence emitter: exploiting the external heavy-atom effect

To attain high efficiencies in hybrid white organic light-emitting diodes(WOLEDs),mutual quenching of the fluorophors and phosphors should be minimized.Efforts have been devoted to reducing the triplet quenching of phosphors;however,the quenching of fluorophors by the external heavy-atom effect(EHA)introduced by the phosphors is often ignored.Here,we observed that conventional fluorophors and fluorophors with thermally activated delayed fluorescence(TADF)behave differently in the presence of EHA perturbers.The efficiencies of the conventional fluorophors suffer greatly from the EHA,whereas the TADF fluorophors exhibit negligible changes,which makes TADF materials ideal fluorophors for hybrid devices.WOLEDs using a blue TADF fluorophor and an orange phosphor achieve a maximum forward viewing external quantum efficiency of 19.6%and a maximum forward viewing power efficiency of 50.2 lm W^(-1),among the best values for hybrid WOLEDs.This report is the first time that the EHA effect has been considered in hybrid WOLEDs and that a general strategy toward highly efficient hybrid WOLEDs with simple structures is proposed.

DGPS在船舶导航定位应用中多径效应的分析

分析了ＧＰＳ多径效应的机理，论述了船舶导航定位应用中岸台与运动台多径噪声的统计特性和频谱特性。分析了非相干包络相关延时锁相环作伪距检测器时，多径噪声时延对直达信号时延估计的影响，指出动态ＤＧＰＳ工作方式时多径噪声可能达到ＧＰＳ工作方式时的倍。

Measurements of effective delayed neutron fraction in a fast neutron reactor using the perturbation method

A perturbation method is proposed to obtain the effective delayed neutron fraction βeff of a cylindrical highly enriched uranium reactor. Based on reactivity measurements with and without a sample at a specified position using the positive period technique, the reactor reactivity perturbation Ap of the sample in βeff units is measured. Simulations of the perturbation experiments are performed using the MCNP program. The PERT card is used to provide the difference dk of effective neutron multiplication factors with and without the sample inside the reactor. Based on the relationship between the effective multiplication factor and the reactivity, the equation βeff=dk/△ρ is derived. In this paper, the reactivity perturbations of 13 metal samples at the designable position of the reactor are measured and calculated. The average βeff value of the reactor is given as 0.00645, and the standard uncertainty is 3.0%. Additionally, the perturbation experiments for fleer can be used to evaluate the reliabilities of the delayed neutron parameters. This work shows that the delayed neutron data of 235U and 23SU froin G.R. Keepin＇s publication are more reliable than those from ENDF-B6.0, ENDF-B7.0, JENDL3.3 and CENDL2.2.

MODELING GENETIC REGULATORY NETWORKS:A DELAY DISCRETE DYNAMICAL MODEL APPROACH

Modeling genetic regulatory networks is an important research topic in genomic research and computationM systems biology. This paper considers the problem of constructing a genetic regula- tory network （GRN） using the discrete dynamic system （DDS） model approach. Although considerable research has been devoted to building GRNs, many of the works did not consider the time-delay effect. Here, the authors propose a time-delay DDS model composed of linear difference equations to represent temporal interactions among significantly expressed genes. The authors also introduce interpolation scheme and re-sampling method for equalizing the non-uniformity of sampling time points. Statistical significance plays an active role in obtaining the optimal interaction matrix of GRNs. The constructed genetic network using linear multiple regression matches with the original data very well. Simulation results are given to demonstrate the effectiveness of the proposed method and model.

Camellia oil trait and DIA quantitative proteomics analyses reveal the impact of harvesting time on the oil content and quality of the late-maturing cultivar C.oleifera‘Huaxin’

Objectives:Harvesting fruits prematurely is a serious problem in many Camellia oleifera‘Huaxin’orchards.Systematic views of dynamic alterations in central metabolism associated with the oil content and oil quality of this cultivar at different harvesting dates were investigated.Materials and Methods:Oil trait analysis was performed in conjunction with data-independent acquisition proteomics analysis using kernels harvested at three time points.Samples were taken from different years and locations to verify oil trait changes,and parallel reaction monitoring(PRM)was performed for some pivotal proteins to validate changes in their abundance.Results:Samples harvested at 6 d after the recommended harvesting date had the highest contents and best fatty acid composition of Camellia oil.A total of 614 differentially accumulated proteins were detected in three pairwise comparisons.Six days prior to the recommended harvesting date,the maximum expression of ribonucloprotein,helicase ATP-binding domain-containing protein,and glycerol kinase and the highest seed moisture content were observed.The highest mitogen-activated protein kinase 6,very-long-chain 3-oxoacyl-CoA reductase and stearoyl-CoA desaturase expression appeared on the recommended harvesting date.A delayed effect was observed for proteomic and oil trait data.Oil trait and PRM validations indicated that the results were highly reliable.Conclusions:The current data strongly suggest that in Guizhou Province,‘Huaxin’cannot be harvested earlier than the recommended harvesting date;appropriately delaying the harvesting time can improve the ultimate production and quality of Camellia oil.

Experimental investigations on triggering characteristic of TVS under DC and AC load

Triggered vacuum switches(TVSs)have fast growing applications in the field of power system and pulse power.The relation between triggering parameters of triggering system,such as triggering voltage and triggering power,between the triggering time delay and its scatter of TVS had been obtained through series of experiments.The result can be adopted as the steering for high-power controller design and application of TVS.A steepened high-voltage triggering pulse is introduced in the main high-voltage generating circuit.As a result,the triggering time delay and its scatter can be decreased remarkably.Synchronous switch technology is imported to control the triggering phase at the crest of applied voltage on TVS.The Triggering characteristic of TVS under alternating current(AC)and direct current(DC)load has been investigated emphatically.Given the identical triggering parameter of triggering system,DC condition is prior to AC on the triggering probability and stability markedly.Such conclusion can be drawn,for AC condition,TVS would require much for the triggering system.

Exploration of whole brain networks modulated by acupuncture at analgesia acupoint ST36 using scale-specific wavelet correlation analysis

Background Previous studies have demonstrated that acupuncture could modulate various brain systems in the resting brain networks. Graph theoretical analysis offers a novel way to investigate the functional organization of the large-scale cortical networks modulated by acupuncture at whole brain level. In this study, we used wavelets correlation analysis to estimate the pairwise correlations between 90 cortical and subcortical human brain regions in normal human volunteers scanned during the post-stimulus resting state. Methods Thirty-two college students, all right-handed and acupuncture na＇fve, participated in this study. Every participant received only one acupoint stimulation, resulting in 16 subjects in one group. Both structural functional magnetic resonance imaging （fMRI） data （3D sequence with a voxel size of 1 mm3 for anatomical localization） and functional fMRI data （TR=1500 ms, TE=30 ms, flip angle=90°） were collected for each subject. After thresholding the resulting scale-specific wavelet correlation matrices to generate undirected binary graphs, we compared graph metrics of brain organization following verum manual acupuncture （ACU） and sham acupuncture （SHAM） groups. Results The topological parameters of the large-scale brain networks in ACU group were different from those of the SHAM group at multiple scales. There existed distinct modularity functional brain networks during the post-stimulus resting state following ACU and SHAM at multiple scales. Conclusions The distinct modulation patterns of the resting brain attributed to the specific effects evoked by acupuncture. In addition, we also identified that there existed frequency-specific modulation in the post-stimulus resting brain following ACU and SHAM. The modulation may be related to the effects of verum acupuncture on modulating special disorder treatment. This preliminary finding may provide a new clue to understand the relatively function- oriented specificity of acupuncture effects.

PECULIARITIES OF IRREVERSIBLE STRAINING IN STEP-WISE LOADING, REVERSE AND INVERSE CREEP

The paper is concerned with the generalization of synthetic theory to the modeling of phenomena such as the Bauschinger negative effect, creep delay, reverse and inverse creep. Detailed calculations of plastic/creep strains are accompanied with the construction of loading surfaces that enhance the understanding of the processes studied. The calculated results show satisfactory agreement with experiments.

Frequency equation for the submicron CMOS ring oscillator using the first order characterization

By utilizing the first order behavior of the device,an equation for the frequency of operation of the submicron CMOS ring oscillator is presented.A 5-stage ring oscillator is utilized as the initial design,with different Beta ratios,for the computation of the operating frequency.Later on,the circuit simulation is performed from 5-stage till 23-stage,with the range of oscillating frequency being 3.0817 and 0.6705 GHz respectively.It is noted that the output frequency is inversely proportional to the square of the device length,and when the value of Beta ratio is used as 2.3,a difference of 3.64%is observed on an average,in between the computed and the simulated values of frequency.As an outcome,the derived equation can be utilized,with the inclusion of an empirical constant in general,for arriving at the ring oscillator circuit’s output frequency.