Generation of single-sideband （SSB） multi-carrier source based on a recirculating frequency shifter （RFS） is anal- ysed theoretically and realized experimentally. The effects of affecting factors originating from ...Generation of single-sideband （SSB） multi-carrier source based on a recirculating frequency shifter （RFS） is anal- ysed theoretically and realized experimentally. The effects of affecting factors originating from the deviation from the right operation bias voltage and unbalanced amplitude, and the phase of the radio frequency （RF） drive signals on the performance of the multi-tone source are discussed in detail. Based on the theoretical analysis, high-quality 50-tone out- put is successfully realized. Experiments under some implementation imperfections are also carried out. The imperfect and low-quality output results are in good agreement with theoretical analysis.展开更多
This paper proposes a robust control-oriented identification method for errors-in-variables(EIV)systems in output feedbacks using frequency-response(FR)experimental data.An important relation between such a closed-loo...This paper proposes a robust control-oriented identification method for errors-in-variables(EIV)systems in output feedbacks using frequency-response(FR)experimental data.An important relation between such a closed-loop EIV system and its coprime factor(CF)uncertainty description is first derived,based on which the FR measurements suitable for plant CF identification are able to be generated.Different factorizations of a given controller in the closed-loop system can be made best use to adjust right coprime factors(RCFs)of the plant so as to realize an improvement on the signal-to-noise ratio of identification experimental data.Subsequently,a nominal RCF model is estimated by linear matrix inequalities from the applicable FR measurements and its associated worst-case errors are quantified from a priori and a posteriori information on the underlying system.A resulting RCF perturbation model set can then be described by the nominal RCF model and its worst-case error bounds.Such a model set capable of being stabilized by the given controller is ready for its robust stabilizing controller redesign and robust performance analysis.Finally,a numerical simulation is given to show the efficacy of the proposed identification method.展开更多
A high-sensitivity,low-noise single photon avalanche diode(SPAD)detector was presented based on a 180 nm BCD process.The proposed device utilizes a p-implant layer/high-voltage n-well(HVNW)junction to form a deep aval...A high-sensitivity,low-noise single photon avalanche diode(SPAD)detector was presented based on a 180 nm BCD process.The proposed device utilizes a p-implant layer/high-voltage n-well(HVNW)junction to form a deep avalanche multiplication region for near-infrared(NIR)sensitivity enhancement.By optimizing the device size and electric field of the guard ring,the fill factor(FF)is significantly improved,further increasing photon detection efficiency(PDE).To solve the dark noise caused by the increasing active diameter,a field polysilicon gate structure connected to the p+anode was investigated,effectively suppressing dark count noise by 76.6%.It is experimentally shown that when the active diameter increases from 5 to 10μm,the FF is significantly improved from 20.7%to 39.1%,and thus the peak PDE also rises from 13.3%to 25.8%.At an excess bias voltage of 5 V,a NIR photon detection probability(PDP)of 6.8%at 905 nm,a dark count rate(DCR)of 2.12 cps/μm^(2),an afterpulsing probability(AP)of 1.2%,and a timing jitter of 216 ps are achieved,demonstrating excellent single photon detection performance.展开更多
In mineral exploration, the apparent resistivity and apparent frequency （or apparent polarizability） parameters of induced polarization method are commonly utilized to describe the induced polarization anomaly. When...In mineral exploration, the apparent resistivity and apparent frequency （or apparent polarizability） parameters of induced polarization method are commonly utilized to describe the induced polarization anomaly. When the target geology structure is significantly complicated, these parameters would fail to reflect the nature of the anomaly source, and wrong conclusions may be obtained. A wavelet approach and a metal factor method were used to comprehensively interpret the induced polarization anomaly of complex geologic bodies in the Adi Bladia mine. Db5 wavelet basis was used to conduct two-scale decomposition and reconstruction, which effectively suppress the noise interference of greenschist facies regional metamorphism and magma intrusion, making energy concentrated and boundary problem unobservable. On the basis of that, the ore-induced anomaly was effectively extracted by the metal factor method.展开更多
Effects of pressure and temperature in the chamber during vacuum drying on the relative humidity and evaporation of wood surface were investigated by using the vacuum chamber. The setting temperature during vacuum dry...Effects of pressure and temperature in the chamber during vacuum drying on the relative humidity and evaporation of wood surface were investigated by using the vacuum chamber. The setting temperature during vacuum drying included dry-bulb temperature ta, the wet-bulb temperature tw and the temperature difference between the air in the vacuum chamber and the cooling water in the condenser. Results indicated that relative humidity during vacuum drying was affected by the dry-bulb temperature td, the wet-bulb temperature tw and the temperature difference between the air in the vacuum chamber and the water in the condenser. Relative humidity of wood decreased with the increase in temperature at the given temperature of the water in the condenser. The relative humidity was affected slightly by pressure in the vacuum chamber pA, and it decreased from 70% to 65% with pA increased from 50 kPa to 101 kPa. Moreover, there was nearly no evaporation under the vacuum without external heating.展开更多
In this paper, three existing source spectral models for stochastic finite-fault modeling of ground motion were reviewed. These three models were used to calculate the far-field received energy at a site from a vertic...In this paper, three existing source spectral models for stochastic finite-fault modeling of ground motion were reviewed. These three models were used to calculate the far-field received energy at a site from a vertical fault and the mean spectral ratio over 15 stations of the Northridge earthquake, and then compared. From the comparison, a necessary measure was observed to maintain the far-field received energy independent of subfault size and avoid overestimation of the long- period spectra/level. Two improvements were made to one of the three models （i.e., the model based on dynamic comer frequency） as follows： （i） a new method to compute the subfault comer frequency was proposed, where the subfault comer frequency is determined based on a basic value calculated from the total seismic moment of the entire fault and an increment depending on the seismic moment assigned to the subfault; and （ii） the difference of the radiation energy from each suhfault was considered into the scaling factor. The improved model was also compared with the unimproved model through the far-field received energy and the mean spectral ratio. The comparison proves that the improved model allows the received energy to be more independent of subfault size than the unimproved model, and decreases the overestimation degree of the long-period spectral amplitude.展开更多
Nerve growth factor(NGF)plays an important role in promoting neuroregeneration after peripheral nerve injury.However,its effects are limited by its short half-life;it is therefore important to identify an effective mo...Nerve growth factor(NGF)plays an important role in promoting neuroregeneration after peripheral nerve injury.However,its effects are limited by its short half-life;it is therefore important to identify an effective mode of administration.High-frequency ultrasound(HFU)is increasingly used in the clinic for high-resolution visualization of tissues,and has been proposed as a method for identifying and evaluating peripheral nerve damage after injury.In addition,HFU is widely used for guiding needle placement when administering drugs to a specific site.We hypothesized that HFU guiding would optimize the neuroprotective effects of NGF on sciatic nerve injury in the rabbit.We performed behavioral,ultrasound,electrophysiological,histological,and immunohistochemical evaluation of HFU-guided NGF injections administered immediately after injury,or 14 days later,and compared this mode of administration with intramuscular NGF injections.Across all assessments,HFU-guided NGF injections gave consistently better outcomes than intramuscular NGF injections administered immediately or 14 days after injury,with immediate treatment also yielding better structural and functional results than when the treatment was delayed by 14 days.Our findings indicate that NGF should be administered as early as possible after peripheral nerve injury,and highlight the striking neuroprotective effects of HFU-guided NGF injections on peripheral nerve injury compared with intramuscular administration.展开更多
In order to contribute to the improvement of brain infarction management in Brazzaville, a cross-sectional and analytical study with prospective data collection was conducted in the cardiology and neurology department...In order to contribute to the improvement of brain infarction management in Brazzaville, a cross-sectional and analytical study with prospective data collection was conducted in the cardiology and neurology departments of the Brazzaville University Hospital, from February 1 to July 31, 2018. It included patients hospitalized for cerebral infarction confirmed with imaging, and having done an etiological assessment with at least one electrocardiogram at rest and one of long duration. Among these 138 patients included, 11 had atrial fibrillation, equaling?a frequency of 7.9%. The mean age of AF patients was 71 ± 8.8 years. The cardiovascular risk factors found were hypertension in eight cases (72.7%), diabetes in five cases (45.5%), abdominal obesity in four cases (36.4%). AF was permanent in 10 cases (91%), and paroxysmal in one case (9%). It was valvular in three cases (27.3%) and non-valvular in eight cases (72.7%). The cardiopathy involved was hypertensive in seven cases (63.6%), ischemic and valvular in two cases each. The CHA2DS2-VASc score, calculated in eight patients, was an average of 2.2, and ≥2 in more than 80% of patients;HAS-BLED score of 2.4 on average was ≥?3 in more than 72% of patients. Digoxin was prescribed in seven cases (63.6%) and an anti-vitamin K in eight cases (72.7%). In multivariate analysis, age (OR = 20.10, p = 0.023), arterial hypertension (OR = 23.82, p = 0.011), and dyslipidemia (OR = 2.03, p = 0.032) were the predictive factors found. AF is infrequent during brain infarction in Brazzaville. This systematic research raises the problem of age in our context.展开更多
The effect of the volume fraction of ferromagnetic metal （x） in （Ni75Fe25）x（ZnO）1-x nanogranular thin films on microstructural, soft-magnetic, and high-frequency properties was investigated. Good soft-magnetic p...The effect of the volume fraction of ferromagnetic metal （x） in （Ni75Fe25）x（ZnO）1-x nanogranular thin films on microstructural, soft-magnetic, and high-frequency properties was investigated. Good soft-magnetic properties were obtained in a broad x range, with 0.55 〈 x 〈 0.82. High resolution transmission electron microscopy （HRTEM） observations reveal that the grain size of the samples is lower than 14 nm, and that it decreases with decreasing x. Of special interest, our investigation of the permeability spectra indicates that these films exhibit an adjustable frequency linewidth of resonance peak, dependant upon changing x. Correspondingly, large and adjustable damping coefficients （aeff） from 0.023 to 0.043 were achieved by decreasing x from 0.82 to 0.55. Combined with the HRTEM results, the variation of αeff with x was analyzed in detail.展开更多
Effects of pressure and temperature in the chamber during vacuum drying on the relative humidity and evaporation of wood surface were investigated by using the vacuum chamber.The setting temperature during vacuum dryi...Effects of pressure and temperature in the chamber during vacuum drying on the relative humidity and evaporation of wood surface were investigated by using the vacuum chamber.The setting temperature during vacuum drying included dry-bulb temperature td,the wet-bulb temperature tw and the temperature difference between the air in the vacuum chamber and the cooling water in the condenser.Results indicated that relative humidity during vacuum drying was affected by the dry-bulb temperature td,the wet-bulb temperature tw and the temperature difference between the air in the vacuum chamber and the water in the condenser.Relative humidity of wood decreased with the increase in temperature at the given temperature of the water in the condenser.The relative humidity was affected slightly by pressure in the vacuum chamber pA,and it decreased from 70%to 65%with pA increased from 50 kPa to 101 kPa.Moreover,there was nearly no evaporation under the vacuum without external heating.展开更多
Background: Autonomic dysfunction in idiopathic Parkinson disease is a frequent and disabling complication, with an estimated prevalence of 47% and has a significant impact on the patient’s quality of life. Objective...Background: Autonomic dysfunction in idiopathic Parkinson disease is a frequent and disabling complication, with an estimated prevalence of 47% and has a significant impact on the patient’s quality of life. Objectives: The main objective of this study was to determine the frequency of autonomic dysfunction among Sudanese Parkinson patients and identify possible risk factors attribute to develop autonomic dysfunction and to assess the extent to which the progression of dysautonomia affects activities of daily living, health-related quality of life. Methods: In this descriptive perspective, cross-sectional hospital-based study, 51 patients were studied using standardized questionnaire including history and clinical examination. Results: A total of 51 patients have been examined: male to female ratio 1.5:1;mean age 55 ± 5 years;Parkinson disease duration, 7 ± 2 years. 47% of the patients had one or more symptoms of autonomic dysfunction with mean age 59 ± 10. Constipation and bloating were the most common symptoms where sweating abnormality was the least symptoms to observe. The symptom of autonomic dysfunction has been worse with disease progression in 50% of the patients and 47% of the patients reported that both motors and autonomic dysfunction symptoms were causing disability than autonomic dysfunction symptoms alone. Conclusions: The study demonstrates that autonomic dysfunction is not only common in Parkinson Disease, but it increases in severity with increasing disease stages. Older age with long disease duration was also considered along with advanced disease stages strong factors determining the presence of autonomic dysfunction. The study recommends that symptoms of autonomic dysfunction survey be a routine aspect of the evaluation of Parkinson disease patients, especially with advanced age.展开更多
<b><span>Background:</span></b><span> </span><span>Periodontitis is a multifactorial disease which is highly preva</span><span>lent worldwide. The control of ...<b><span>Background:</span></b><span> </span><span>Periodontitis is a multifactorial disease which is highly preva</span><span>lent worldwide. The control of periodontal risk factor network is of para</span><span>mount importance for the management of the disease.</span><span> </span><b><span>Aim:</span></b><b><span> </span></b><span>The aim of </span><span>this study was to assess the frequency and identify the factors associated wit</span><span>h periodontitis in Congolese patients.</span><span> </span><b><span>Material and Methods</span></b><b><span>:</span></b><span> </span><span>This cross-sectional study was carried out in four medical centers in the city of Kinshasa between April 2017 and April 2018. The study included patients aged at least 12 years old who consulted the dental services of these centers and who met the inclusion criteria. The participants underwent a structured interview and a clinical periodontal examination. The latter involved the entire dentition, and periodontal pocket and attachment level measurements were taken at six sites per tooth. The plaque and bleeding index were recorded. Logistic regression was used to identify associated factors. The significance level was set at p</span><span> < </span><span>0.05.</span><span> </span><b><span>Results</span></b><b><span>:</span></b><span> </span><span>The study included 827 patients and 42% of them had periodontitis. The most represented age group was between 20 and 29 years old. In multivariate analysis, age greater than or equal to 35 years, OR = 2.45 CI 95% (1.77</span><span> </span><span>-</span><span> </span><span>3.45), and the amount of plaque expressed as plaque index ≥</span><span> </span><span>1, OR = 2 CI </span><span>95% (1.31 </span><span>-</span><span> 3.07) were factors associated with periodontitis.</span><span> </span><b><span>Conclusion</span></b><b><span>:</span></b><span> </span><span>Factors associated with periodontitis found in this study are age ≥35 years and the amount of plaque expressed as plaque index ≥</span><span> </span><span>1. The latter reveals the importance of good oral hygiene.</span>展开更多
The characteristics of temporal and spatial distribution of tropical cyclone frequencies over the South China Sea areas and its affecting factors in the past 50yrs are analyzed based on typhoon data that provided by C...The characteristics of temporal and spatial distribution of tropical cyclone frequencies over the South China Sea areas and its affecting factors in the past 50yrs are analyzed based on typhoon data that provided by CMA and Simple Ocean Data Assimilation （SODA）. The results show that the tropical cyclone frequencies from June to October show concentrated geographic distribution, for they mainIy distribute over the SCS area from 15 - 20°N. The characteristics present significant interdecadal changes. The impact of oceanic factors on the tropical cyclone frequencies in the SCS area is mainly realized by La Nina and La Nifia-like events before 1975 but mainly by E1 Nino and E1 Nifio-like events after 1975.展开更多
Background: Knowledge of temporal evolution of preeclampsia (PE) in its various aspects is essential in strategies to reduce maternal and perinatal morbidity and mortality. Preeclampsia is a public health problem due ...Background: Knowledge of temporal evolution of preeclampsia (PE) in its various aspects is essential in strategies to reduce maternal and perinatal morbidity and mortality. Preeclampsia is a public health problem due to maternal mortality associated with it worldwide (5.6%). Improving quality of its management is a major challenge in low-income countries where, despite progress made in this field, PE remains a major factor in maternal morbidity and mortality. Objective: To evaluate temporal evolution of frequency, risk factors and complications of PE at the University clinics of Kinshasa (UCK). Methods: Descriptive and cross-sectional study concerning minimum simple size of 119 pregnant women who consulted for antenatal care at the University clinics of Kinshasa from January 2012 to December 2022. Results will be reported as percentage proportion, mean and standard deviation. Comparison of proportion and means between groups will be made using Student’s t-test and Pearson’s chi-square test, respectively. The test will be statistically significant for a p value ≤ less than 0.05. Data will be collected and analysed anonymously and confidentially. Conclusion: This study will allow us to evaluate the effectiveness of different prevention and treatment modalities used over time in management of preeclampsia in our setting.展开更多
Introduction: Obstetric emergencies are clinical situations of a serious nature, often dangerous, which develop unexpectedly, threatening the vital prognosis of the mother and/or foetus in the short term. The aim of t...Introduction: Obstetric emergencies are clinical situations of a serious nature, often dangerous, which develop unexpectedly, threatening the vital prognosis of the mother and/or foetus in the short term. The aim of this study was to contribute to a review of obstetric emergencies at the Labé Regional Hospital maternity unit. Methods: This was a prospective descriptive and analytical study conducted over a period of 6 months in the maternity unit of the Labé Regional Hospital. It concerned all patients admitted to the department for obstetric emergencies. Results: Obstetric emergencies accounted for 20% of obstetric admissions. The mean age of the patients was 25.12 ± 7.15 years, with extremes of 14 and 45 years. The patients were housewives (42.52%), 42.86% did not attend school and 77.41% were from urban areas. The poor were the most numerous (43.52%). The ambulance was the means of transport in only 9% of cases. Acute foetal distress, pre-eclampsia, bony dystocia and post-partum haemorrhage were the most common types of emergency in our series, with frequencies of 27.57%, 22.59%, 17.94% and 10.63% respectively. The risk factors identified were age, origin, gestational age and the state of the maternal pelvis. Conclusion: Obstetric emergencies are frequent in our study site and represent a major concern for patients, providers and the community alike. In order to reduce the frequency of obstetric emergencies, young girls should be enrolled in school, the legal age for marriage should be respected, quality antenatal care should be provided in basic health facilities, and proper planning and spacing of pregnancies should be implemented.展开更多
Based on the Gauss linear frequency modulated wavelet transform, a new characteristic index is presented, namely time frequency energy attenuation factor which can reflect the difference features of waveform in earthq...Based on the Gauss linear frequency modulated wavelet transform, a new characteristic index is presented, namely time frequency energy attenuation factor which can reflect the difference features of waveform in earthquake focus mechanism, wave traveling path and its attenuation characteristics in focal area or near field. In order to test its validity, we select the natural earthquakes and explosion or collapse events whose focus mechanisms vary obviously,and some natural earthquakes located at the same site or in a very small area. The study indicates that the time frequency energy attenuation factors of the natural earthquakes are obviously different with that of explosion or collapse events, and the change of the time frequency energy attenuation factors is relatively stable for the earthquakes under the normal seismicity background. Using the above mentioned method, it is expected to offer a useful criterion for strong earthquake prediction by continuous earthquake observation.展开更多
BACKGROUND Bowel preparation is a critical step in colonoscopy and endoscopic surgery.Adequate and effective bowel cleansing significantly improves lesion detection rates while reducing operative risks and complicatio...BACKGROUND Bowel preparation is a critical step in colonoscopy and endoscopic surgery.Adequate and effective bowel cleansing significantly improves lesion detection rates while reducing operative risks and complications.AIM To investigate the current state of inadequate bowel preparation in patients undergoing colonoscopy,identify the contributing factors,and develop interventions.METHODS This study was designed as a retrospective cohort study.A convenience sampling method was used to select 484 patients who underwent colonoscopy at Beijing Chao-Yang Hospital,Capital Medical University,from October 2023 to October 2024.General patient data,disease-related variables,and the Boston bowel preparation scale were collected.Logistic regression analysis was conducted to identify the factors associated with inadequate bowel preparation.RESULTS Among the 484 patients,the rate of inadequate bowel preparation was 25.8%(125/484).Influential factors for poor bowel preparation included history of colorectal surgery[odds ratio(OR)=5.814],low-residue diet 1 day prior(OR=0.145),time interval from last dose to start of examination(OR=1.447),total exercise time after medication(OR=0.992),and total number of bowel movements after medication(OR=0.900)(all P<0.05).CONCLUSION This study highlights several modifiable and non-modifiable factors influencing bowel preparation,such as surgical history and behavioral adherence.The findings support implementing dietary adjustments,optimized laxative timing,physical activity guidance,and tailored strategies for high-risk patients to improve bowel cleansing and enhance the diagnostic accuracy of colonoscopy.展开更多
Connection methods are essential for integrating environmental factors with machine learning models for landslide susceptibility assessments.However,current research does not consider the different characteristics of ...Connection methods are essential for integrating environmental factors with machine learning models for landslide susceptibility assessments.However,current research does not consider the different characteristics of continuity and discreteness within environmental factors and therefore does not analyze the suitability of various connection methods for different factor types.Moreover,the applicability of connection methods remains unclear when slope units are used as the basic assessment units.This study employed slope units as mapping units.The original data of 15 environmental factors,including 12 continuous and three discrete factors,and two connection methods,i.e.,frequency ratio(FR)and modified FR(MFR),were separately used to construct the input datasets for landslide susceptibility modeling.The performance of four widely used machine learning models,random forest(RF),support vector machine(SVM),logistic regression(LR),and multilayer perceptron(MLP),was analyzed to evaluate the suitability of the connection methods for landslide susceptibility mapping.The results show that,in contrast to the decision tree-based RF model,the use of different connection methods for different factor types significantly influences the results of nontree models,including SVM,MLP,and LR.SVM model is the most sensitive to factor types and connection methods.When the MFR is used as the connection method,it improves the mapping results,especially for the SVM model.This shows that it is essential to consider the different characteristics of the data and select an appropriate environmental factor connection strategy to increase the effectiveness of landslide susceptibility evaluation.Furthermore,this study explored the role of connective methods from a sample distribution perspective,providing a theoretical foundation for the more rational and effective integration of environmental factors.展开更多
Martens proposed a highly efficient and simply formed DFT algorithm——RCFA,whose efficien-cy is comparable with that of WFTA or that of PFA,and whose structure is similar to that of FFT.Theauthors have proved that,in...Martens proposed a highly efficient and simply formed DFT algorithm——RCFA,whose efficien-cy is comparable with that of WFTA or that of PFA,and whose structure is similar to that of FFT.Theauthors have proved that,in the case of radix 2,the RCFA is exactly equivalent to the twiddle factor mergedfrequency-decimal FFT algorithm.The twiddle factor merged time-decimal FFT algorithm is providedin this paper.Thus,in any case,the FFT algorithm used currently can be replaced by the more efficientalgorithm——the twiddle factor merged FFT algorithm,with exactly the same external property and thesimilar internal structure.Also in this paper,the software for implementing the twiddle factor merged FFTalgorithm(TMFFT)is provided.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No.60977049)the Chinese Universities Scientific Fund (Grant No.BUPT 2009RC0413)
文摘Generation of single-sideband （SSB） multi-carrier source based on a recirculating frequency shifter （RFS） is anal- ysed theoretically and realized experimentally. The effects of affecting factors originating from the deviation from the right operation bias voltage and unbalanced amplitude, and the phase of the radio frequency （RF） drive signals on the performance of the multi-tone source are discussed in detail. Based on the theoretical analysis, high-quality 50-tone out- put is successfully realized. Experiments under some implementation imperfections are also carried out. The imperfect and low-quality output results are in good agreement with theoretical analysis.
文摘This paper proposes a robust control-oriented identification method for errors-in-variables(EIV)systems in output feedbacks using frequency-response(FR)experimental data.An important relation between such a closed-loop EIV system and its coprime factor(CF)uncertainty description is first derived,based on which the FR measurements suitable for plant CF identification are able to be generated.Different factorizations of a given controller in the closed-loop system can be made best use to adjust right coprime factors(RCFs)of the plant so as to realize an improvement on the signal-to-noise ratio of identification experimental data.Subsequently,a nominal RCF model is estimated by linear matrix inequalities from the applicable FR measurements and its associated worst-case errors are quantified from a priori and a posteriori information on the underlying system.A resulting RCF perturbation model set can then be described by the nominal RCF model and its worst-case error bounds.Such a model set capable of being stabilized by the given controller is ready for its robust stabilizing controller redesign and robust performance analysis.Finally,a numerical simulation is given to show the efficacy of the proposed identification method.
基金supported by the National Natural Science Foundation of China under Grant 62171233the Natural Science Foundation of China,Jiangsu Province under Grant BK20241891the Jiangsu Province Graduate Research and Practice Innovation Plan under Grants SJCX24_0313 and KYCX24_1169。
文摘A high-sensitivity,low-noise single photon avalanche diode(SPAD)detector was presented based on a 180 nm BCD process.The proposed device utilizes a p-implant layer/high-voltage n-well(HVNW)junction to form a deep avalanche multiplication region for near-infrared(NIR)sensitivity enhancement.By optimizing the device size and electric field of the guard ring,the fill factor(FF)is significantly improved,further increasing photon detection efficiency(PDE).To solve the dark noise caused by the increasing active diameter,a field polysilicon gate structure connected to the p+anode was investigated,effectively suppressing dark count noise by 76.6%.It is experimentally shown that when the active diameter increases from 5 to 10μm,the FF is significantly improved from 20.7%to 39.1%,and thus the peak PDE also rises from 13.3%to 25.8%.At an excess bias voltage of 5 V,a NIR photon detection probability(PDP)of 6.8%at 905 nm,a dark count rate(DCR)of 2.12 cps/μm^(2),an afterpulsing probability(AP)of 1.2%,and a timing jitter of 216 ps are achieved,demonstrating excellent single photon detection performance.
基金Project(41174103)supported by the National Natural Science Foundation of ChinaProject(2010-211)supported by the Foreign Mineral Resources Venture Exploration Special Fund of China
文摘In mineral exploration, the apparent resistivity and apparent frequency （or apparent polarizability） parameters of induced polarization method are commonly utilized to describe the induced polarization anomaly. When the target geology structure is significantly complicated, these parameters would fail to reflect the nature of the anomaly source, and wrong conclusions may be obtained. A wavelet approach and a metal factor method were used to comprehensively interpret the induced polarization anomaly of complex geologic bodies in the Adi Bladia mine. Db5 wavelet basis was used to conduct two-scale decomposition and reconstruction, which effectively suppress the noise interference of greenschist facies regional metamorphism and magma intrusion, making energy concentrated and boundary problem unobservable. On the basis of that, the ore-induced anomaly was effectively extracted by the metal factor method.
文摘Effects of pressure and temperature in the chamber during vacuum drying on the relative humidity and evaporation of wood surface were investigated by using the vacuum chamber. The setting temperature during vacuum drying included dry-bulb temperature ta, the wet-bulb temperature tw and the temperature difference between the air in the vacuum chamber and the cooling water in the condenser. Results indicated that relative humidity during vacuum drying was affected by the dry-bulb temperature td, the wet-bulb temperature tw and the temperature difference between the air in the vacuum chamber and the water in the condenser. Relative humidity of wood decreased with the increase in temperature at the given temperature of the water in the condenser. The relative humidity was affected slightly by pressure in the vacuum chamber pA, and it decreased from 70% to 65% with pA increased from 50 kPa to 101 kPa. Moreover, there was nearly no evaporation under the vacuum without external heating.
基金National Natural Science Foundation of China Under Grant No. 50778058 and 90715038National Key Technology R&D Program Under Contract No. 2006BAC13B02
文摘In this paper, three existing source spectral models for stochastic finite-fault modeling of ground motion were reviewed. These three models were used to calculate the far-field received energy at a site from a vertical fault and the mean spectral ratio over 15 stations of the Northridge earthquake, and then compared. From the comparison, a necessary measure was observed to maintain the far-field received energy independent of subfault size and avoid overestimation of the long- period spectra/level. Two improvements were made to one of the three models （i.e., the model based on dynamic comer frequency） as follows： （i） a new method to compute the subfault comer frequency was proposed, where the subfault comer frequency is determined based on a basic value calculated from the total seismic moment of the entire fault and an increment depending on the seismic moment assigned to the subfault; and （ii） the difference of the radiation energy from each suhfault was considered into the scaling factor. The improved model was also compared with the unimproved model through the far-field received energy and the mean spectral ratio. The comparison proves that the improved model allows the received energy to be more independent of subfault size than the unimproved model, and decreases the overestimation degree of the long-period spectral amplitude.
基金supported by the National Natural Science Foundation of China,No.81100922
文摘Nerve growth factor(NGF)plays an important role in promoting neuroregeneration after peripheral nerve injury.However,its effects are limited by its short half-life;it is therefore important to identify an effective mode of administration.High-frequency ultrasound(HFU)is increasingly used in the clinic for high-resolution visualization of tissues,and has been proposed as a method for identifying and evaluating peripheral nerve damage after injury.In addition,HFU is widely used for guiding needle placement when administering drugs to a specific site.We hypothesized that HFU guiding would optimize the neuroprotective effects of NGF on sciatic nerve injury in the rabbit.We performed behavioral,ultrasound,electrophysiological,histological,and immunohistochemical evaluation of HFU-guided NGF injections administered immediately after injury,or 14 days later,and compared this mode of administration with intramuscular NGF injections.Across all assessments,HFU-guided NGF injections gave consistently better outcomes than intramuscular NGF injections administered immediately or 14 days after injury,with immediate treatment also yielding better structural and functional results than when the treatment was delayed by 14 days.Our findings indicate that NGF should be administered as early as possible after peripheral nerve injury,and highlight the striking neuroprotective effects of HFU-guided NGF injections on peripheral nerve injury compared with intramuscular administration.
文摘In order to contribute to the improvement of brain infarction management in Brazzaville, a cross-sectional and analytical study with prospective data collection was conducted in the cardiology and neurology departments of the Brazzaville University Hospital, from February 1 to July 31, 2018. It included patients hospitalized for cerebral infarction confirmed with imaging, and having done an etiological assessment with at least one electrocardiogram at rest and one of long duration. Among these 138 patients included, 11 had atrial fibrillation, equaling?a frequency of 7.9%. The mean age of AF patients was 71 ± 8.8 years. The cardiovascular risk factors found were hypertension in eight cases (72.7%), diabetes in five cases (45.5%), abdominal obesity in four cases (36.4%). AF was permanent in 10 cases (91%), and paroxysmal in one case (9%). It was valvular in three cases (27.3%) and non-valvular in eight cases (72.7%). The cardiopathy involved was hypertensive in seven cases (63.6%), ischemic and valvular in two cases each. The CHA2DS2-VASc score, calculated in eight patients, was an average of 2.2, and ≥2 in more than 80% of patients;HAS-BLED score of 2.4 on average was ≥?3 in more than 72% of patients. Digoxin was prescribed in seven cases (63.6%) and an anti-vitamin K in eight cases (72.7%). In multivariate analysis, age (OR = 20.10, p = 0.023), arterial hypertension (OR = 23.82, p = 0.011), and dyslipidemia (OR = 2.03, p = 0.032) were the predictive factors found. AF is infrequent during brain infarction in Brazzaville. This systematic research raises the problem of age in our context.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.50901050 and 51101079)
文摘The effect of the volume fraction of ferromagnetic metal （x） in （Ni75Fe25）x（ZnO）1-x nanogranular thin films on microstructural, soft-magnetic, and high-frequency properties was investigated. Good soft-magnetic properties were obtained in a broad x range, with 0.55 〈 x 〈 0.82. High resolution transmission electron microscopy （HRTEM） observations reveal that the grain size of the samples is lower than 14 nm, and that it decreases with decreasing x. Of special interest, our investigation of the permeability spectra indicates that these films exhibit an adjustable frequency linewidth of resonance peak, dependant upon changing x. Correspondingly, large and adjustable damping coefficients （aeff） from 0.023 to 0.043 were achieved by decreasing x from 0.82 to 0.55. Combined with the HRTEM results, the variation of αeff with x was analyzed in detail.
基金supported by National Natural Science Foundation of China(No.30571453)Heilongjiang Postdoc-toral Science-Research Foundation(No.LBH-Q06116).
文摘Effects of pressure and temperature in the chamber during vacuum drying on the relative humidity and evaporation of wood surface were investigated by using the vacuum chamber.The setting temperature during vacuum drying included dry-bulb temperature td,the wet-bulb temperature tw and the temperature difference between the air in the vacuum chamber and the cooling water in the condenser.Results indicated that relative humidity during vacuum drying was affected by the dry-bulb temperature td,the wet-bulb temperature tw and the temperature difference between the air in the vacuum chamber and the water in the condenser.Relative humidity of wood decreased with the increase in temperature at the given temperature of the water in the condenser.The relative humidity was affected slightly by pressure in the vacuum chamber pA,and it decreased from 70%to 65%with pA increased from 50 kPa to 101 kPa.Moreover,there was nearly no evaporation under the vacuum without external heating.
文摘Background: Autonomic dysfunction in idiopathic Parkinson disease is a frequent and disabling complication, with an estimated prevalence of 47% and has a significant impact on the patient’s quality of life. Objectives: The main objective of this study was to determine the frequency of autonomic dysfunction among Sudanese Parkinson patients and identify possible risk factors attribute to develop autonomic dysfunction and to assess the extent to which the progression of dysautonomia affects activities of daily living, health-related quality of life. Methods: In this descriptive perspective, cross-sectional hospital-based study, 51 patients were studied using standardized questionnaire including history and clinical examination. Results: A total of 51 patients have been examined: male to female ratio 1.5:1;mean age 55 ± 5 years;Parkinson disease duration, 7 ± 2 years. 47% of the patients had one or more symptoms of autonomic dysfunction with mean age 59 ± 10. Constipation and bloating were the most common symptoms where sweating abnormality was the least symptoms to observe. The symptom of autonomic dysfunction has been worse with disease progression in 50% of the patients and 47% of the patients reported that both motors and autonomic dysfunction symptoms were causing disability than autonomic dysfunction symptoms alone. Conclusions: The study demonstrates that autonomic dysfunction is not only common in Parkinson Disease, but it increases in severity with increasing disease stages. Older age with long disease duration was also considered along with advanced disease stages strong factors determining the presence of autonomic dysfunction. The study recommends that symptoms of autonomic dysfunction survey be a routine aspect of the evaluation of Parkinson disease patients, especially with advanced age.
文摘<b><span>Background:</span></b><span> </span><span>Periodontitis is a multifactorial disease which is highly preva</span><span>lent worldwide. The control of periodontal risk factor network is of para</span><span>mount importance for the management of the disease.</span><span> </span><b><span>Aim:</span></b><b><span> </span></b><span>The aim of </span><span>this study was to assess the frequency and identify the factors associated wit</span><span>h periodontitis in Congolese patients.</span><span> </span><b><span>Material and Methods</span></b><b><span>:</span></b><span> </span><span>This cross-sectional study was carried out in four medical centers in the city of Kinshasa between April 2017 and April 2018. The study included patients aged at least 12 years old who consulted the dental services of these centers and who met the inclusion criteria. The participants underwent a structured interview and a clinical periodontal examination. The latter involved the entire dentition, and periodontal pocket and attachment level measurements were taken at six sites per tooth. The plaque and bleeding index were recorded. Logistic regression was used to identify associated factors. The significance level was set at p</span><span> < </span><span>0.05.</span><span> </span><b><span>Results</span></b><b><span>:</span></b><span> </span><span>The study included 827 patients and 42% of them had periodontitis. The most represented age group was between 20 and 29 years old. In multivariate analysis, age greater than or equal to 35 years, OR = 2.45 CI 95% (1.77</span><span> </span><span>-</span><span> </span><span>3.45), and the amount of plaque expressed as plaque index ≥</span><span> </span><span>1, OR = 2 CI </span><span>95% (1.31 </span><span>-</span><span> 3.07) were factors associated with periodontitis.</span><span> </span><b><span>Conclusion</span></b><b><span>:</span></b><span> </span><span>Factors associated with periodontitis found in this study are age ≥35 years and the amount of plaque expressed as plaque index ≥</span><span> </span><span>1. The latter reveals the importance of good oral hygiene.</span>
基金Research on Techniques of Predicting the Prospects of Drought and Flood Years inGuangdong – a project of the Science and Technology Plan of Guangdong Province (2005B32601007)Experiments with the Coupling between Typhoons, Waves and Storm Surges and Pre-estimation of Typhoon-inflicted Dagames, a project of the Research Fund for Tropical Oceanic and Meteorological Science
文摘The characteristics of temporal and spatial distribution of tropical cyclone frequencies over the South China Sea areas and its affecting factors in the past 50yrs are analyzed based on typhoon data that provided by CMA and Simple Ocean Data Assimilation （SODA）. The results show that the tropical cyclone frequencies from June to October show concentrated geographic distribution, for they mainIy distribute over the SCS area from 15 - 20°N. The characteristics present significant interdecadal changes. The impact of oceanic factors on the tropical cyclone frequencies in the SCS area is mainly realized by La Nina and La Nifia-like events before 1975 but mainly by E1 Nino and E1 Nifio-like events after 1975.
文摘Background: Knowledge of temporal evolution of preeclampsia (PE) in its various aspects is essential in strategies to reduce maternal and perinatal morbidity and mortality. Preeclampsia is a public health problem due to maternal mortality associated with it worldwide (5.6%). Improving quality of its management is a major challenge in low-income countries where, despite progress made in this field, PE remains a major factor in maternal morbidity and mortality. Objective: To evaluate temporal evolution of frequency, risk factors and complications of PE at the University clinics of Kinshasa (UCK). Methods: Descriptive and cross-sectional study concerning minimum simple size of 119 pregnant women who consulted for antenatal care at the University clinics of Kinshasa from January 2012 to December 2022. Results will be reported as percentage proportion, mean and standard deviation. Comparison of proportion and means between groups will be made using Student’s t-test and Pearson’s chi-square test, respectively. The test will be statistically significant for a p value ≤ less than 0.05. Data will be collected and analysed anonymously and confidentially. Conclusion: This study will allow us to evaluate the effectiveness of different prevention and treatment modalities used over time in management of preeclampsia in our setting.
文摘Introduction: Obstetric emergencies are clinical situations of a serious nature, often dangerous, which develop unexpectedly, threatening the vital prognosis of the mother and/or foetus in the short term. The aim of this study was to contribute to a review of obstetric emergencies at the Labé Regional Hospital maternity unit. Methods: This was a prospective descriptive and analytical study conducted over a period of 6 months in the maternity unit of the Labé Regional Hospital. It concerned all patients admitted to the department for obstetric emergencies. Results: Obstetric emergencies accounted for 20% of obstetric admissions. The mean age of the patients was 25.12 ± 7.15 years, with extremes of 14 and 45 years. The patients were housewives (42.52%), 42.86% did not attend school and 77.41% were from urban areas. The poor were the most numerous (43.52%). The ambulance was the means of transport in only 9% of cases. Acute foetal distress, pre-eclampsia, bony dystocia and post-partum haemorrhage were the most common types of emergency in our series, with frequencies of 27.57%, 22.59%, 17.94% and 10.63% respectively. The risk factors identified were age, origin, gestational age and the state of the maternal pelvis. Conclusion: Obstetric emergencies are frequent in our study site and represent a major concern for patients, providers and the community alike. In order to reduce the frequency of obstetric emergencies, young girls should be enrolled in school, the legal age for marriage should be respected, quality antenatal care should be provided in basic health facilities, and proper planning and spacing of pregnancies should be implemented.
文摘Based on the Gauss linear frequency modulated wavelet transform, a new characteristic index is presented, namely time frequency energy attenuation factor which can reflect the difference features of waveform in earthquake focus mechanism, wave traveling path and its attenuation characteristics in focal area or near field. In order to test its validity, we select the natural earthquakes and explosion or collapse events whose focus mechanisms vary obviously,and some natural earthquakes located at the same site or in a very small area. The study indicates that the time frequency energy attenuation factors of the natural earthquakes are obviously different with that of explosion or collapse events, and the change of the time frequency energy attenuation factors is relatively stable for the earthquakes under the normal seismicity background. Using the above mentioned method, it is expected to offer a useful criterion for strong earthquake prediction by continuous earthquake observation.
基金Supported by the Beijing Key Clinical Specialty Project.
文摘BACKGROUND Bowel preparation is a critical step in colonoscopy and endoscopic surgery.Adequate and effective bowel cleansing significantly improves lesion detection rates while reducing operative risks and complications.AIM To investigate the current state of inadequate bowel preparation in patients undergoing colonoscopy,identify the contributing factors,and develop interventions.METHODS This study was designed as a retrospective cohort study.A convenience sampling method was used to select 484 patients who underwent colonoscopy at Beijing Chao-Yang Hospital,Capital Medical University,from October 2023 to October 2024.General patient data,disease-related variables,and the Boston bowel preparation scale were collected.Logistic regression analysis was conducted to identify the factors associated with inadequate bowel preparation.RESULTS Among the 484 patients,the rate of inadequate bowel preparation was 25.8%(125/484).Influential factors for poor bowel preparation included history of colorectal surgery[odds ratio(OR)=5.814],low-residue diet 1 day prior(OR=0.145),time interval from last dose to start of examination(OR=1.447),total exercise time after medication(OR=0.992),and total number of bowel movements after medication(OR=0.900)(all P<0.05).CONCLUSION This study highlights several modifiable and non-modifiable factors influencing bowel preparation,such as surgical history and behavioral adherence.The findings support implementing dietary adjustments,optimized laxative timing,physical activity guidance,and tailored strategies for high-risk patients to improve bowel cleansing and enhance the diagnostic accuracy of colonoscopy.
基金supported by the National Key Research and Development Program of China(No.2023YFC3007202)Joint Research Project on Meteorological Capacity Enhancement of the China Meteorological Administration(No.23NLTSZ009)Project of the Department of Science and Technology of Sichuan Province(No.2024YFHZ0098)。
文摘Connection methods are essential for integrating environmental factors with machine learning models for landslide susceptibility assessments.However,current research does not consider the different characteristics of continuity and discreteness within environmental factors and therefore does not analyze the suitability of various connection methods for different factor types.Moreover,the applicability of connection methods remains unclear when slope units are used as the basic assessment units.This study employed slope units as mapping units.The original data of 15 environmental factors,including 12 continuous and three discrete factors,and two connection methods,i.e.,frequency ratio(FR)and modified FR(MFR),were separately used to construct the input datasets for landslide susceptibility modeling.The performance of four widely used machine learning models,random forest(RF),support vector machine(SVM),logistic regression(LR),and multilayer perceptron(MLP),was analyzed to evaluate the suitability of the connection methods for landslide susceptibility mapping.The results show that,in contrast to the decision tree-based RF model,the use of different connection methods for different factor types significantly influences the results of nontree models,including SVM,MLP,and LR.SVM model is the most sensitive to factor types and connection methods.When the MFR is used as the connection method,it improves the mapping results,especially for the SVM model.This shows that it is essential to consider the different characteristics of the data and select an appropriate environmental factor connection strategy to increase the effectiveness of landslide susceptibility evaluation.Furthermore,this study explored the role of connective methods from a sample distribution perspective,providing a theoretical foundation for the more rational and effective integration of environmental factors.
文摘Martens proposed a highly efficient and simply formed DFT algorithm——RCFA,whose efficien-cy is comparable with that of WFTA or that of PFA,and whose structure is similar to that of FFT.Theauthors have proved that,in the case of radix 2,the RCFA is exactly equivalent to the twiddle factor mergedfrequency-decimal FFT algorithm.The twiddle factor merged time-decimal FFT algorithm is providedin this paper.Thus,in any case,the FFT algorithm used currently can be replaced by the more efficientalgorithm——the twiddle factor merged FFT algorithm,with exactly the same external property and thesimilar internal structure.Also in this paper,the software for implementing the twiddle factor merged FFTalgorithm(TMFFT)is provided.
