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Influence of soaking time on nonlinear electrical behavior and dielectric properties of TiO_2-based varistor ceramics 被引量:4
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作者 孟凡明 鲁飞 +1 位作者 肖磊 孙兆奇 《Journal of Central South University》 SCIE EI CAS 2009年第6期897-901,共5页
The influence of soaking time on the nonlinear electrical behavior and dielectric properties of TiO2-based varistor ceramics was investigated. Based on single sintering process, six disk samples of (Sr, Bi, Si, Ta)-... The influence of soaking time on the nonlinear electrical behavior and dielectric properties of TiO2-based varistor ceramics was investigated. Based on single sintering process, six disk samples of (Sr, Bi, Si, Ta)-doped TiO2-based varistor ceramics were fabricated by sintering at 1 250 ℃ for 0.5-5.0 h. The samples were characterized by X-ray diffraction, voltage-current characteristics, energy spectra, metallographs, breakdown voltages, and apparent dielectric constant. It is found that the breakdown electrical field intensity at a current density of 10 mA/cma decreases from 5.5 to 4.1 V/mm first and then increases to 7.0 V/mm, the nonlinear coefficient increases from 2.39 to 2.62 first and then decreases to 2.42, and the apparent dielectric constant increases from 98 200 to 1l5 049 first and then decreases to 73 865 with the soaking time increasing from 0.5 to 5.0 h. These indicate that the optimal soaking time is 2.0-3.0 h considering both nonlinear electrical behavior and dielectric properties. 展开更多
关键词 TiO2 varistor ceramics breakdown voltage nonlinear coefficient dielectric constant soaking time
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Influence of soaking time on semi-conductivity and nonlinear electrical properties of TiO_2-based varistor ceramics 被引量:4
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作者 孟凡明 《Journal of Chongqing University》 CAS 2008年第4期297-301,共5页
We investigated the influence of soaking time on the semi-conductivity and nonlinear electrical properties of TiO2- based varistor ceramic samples. We used a single sintering process and fabricated six disk samples of... We investigated the influence of soaking time on the semi-conductivity and nonlinear electrical properties of TiO2- based varistor ceramic samples. We used a single sintering process and fabricated six disk samples of (Sr, Bi, Si, Ta)-doped TiO2- based varistor ceramics sintered at 1 250℃ for 0.5 h, 1.0 h, 2.0 h, 3.0 h, 4.0 h, and 5.0 h, respectively. The samples were characterized by X-ray diffraction, breakdown voltage, and complex impedance. The results show that as the soaking time increases from 0.5 h to 5.0 h, the breakdown voltage drops before rising while the nonlinear coefficient increases and then decreases. We suggest that, considering both grain semi-conductivity and nonlinear electrical properties of the TiO2-based varistor ceramics, the optimal soaking time is between 2.0 h and 3.0 h. 展开更多
关键词 TiO2-based varistor ceramics nonlinear electrical properties semi-conductivity soaking time
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Effect of GA_(3) Concentration and Soaking Time on Seed Germination Characteristics of Blueberry 被引量:4
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作者 HU Xuan-ping 《Agricultural Science & Technology》 CAS 2022年第2期7-11,共5页
This study aims to explore the effect of GA_(3) concentration and soaking time on seed germination characteristics of blueberry.To be specific,big(B),medium-sized(M),and small(S)blueberry seeds were soaked in 0,100,20... This study aims to explore the effect of GA_(3) concentration and soaking time on seed germination characteristics of blueberry.To be specific,big(B),medium-sized(M),and small(S)blueberry seeds were soaked in 0,100,200,and 300 mg/L GA_(3) solution for 18 h and 200 mg/L GA_(3) solution for 0,24,and 48 h,respectively.The results showed that 300 mg/L GA_(3) had significant effect on the germination of B and M seeds(P<0.01)and enabled the germination 4~5 d and 7~8 d earlier,respectively.Soaking with 200 mg/L GA_(3) for 24 h was conducive to the germination of B and M seeds(P<0.05).However,GA_(3) concentration and soaking time had no obviously promoting effect on the germination of S seeds.The interactions between GA_(3) concentration and seed size and between soaking time and seed size were significant(P<0.01). 展开更多
关键词 Blueberry seeds GA_(3)concentration soaking time Germination characteristics
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Susceptible time window and endurable duration of cotton fiber development to high temperature stress 被引量:2
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作者 XU Bo ZHOU Zhi-guo +5 位作者 GUO Lin-tao XU Wen-zheng ZHAO Wen-qin CHEN Bing-lin MENG Ya-li WANG You-hua 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2017年第9期1936-1945,共10页
The development of the cotton fiber is very sensitive to temperature variation, and high temperature stress often causes reduced fiber yield and fiber quality. Short-term high temperature stress often occurs during co... The development of the cotton fiber is very sensitive to temperature variation, and high temperature stress often causes reduced fiber yield and fiber quality. Short-term high temperature stress often occurs during cotton production, but little is known about the specific timing and duration of stress that affects fiber development. To make this clear, pot experiments were carried in 2014 and 2015 in a climate chamber using cotton cultivars HY370WR(less sensitive variety) and Sumian 15(heat sensitive variety), which present different temperature sensitivities. Changes of the most important fiber quality indices(i.e., fiber length, fiber strength and marcironaire) and three very important fiber development components(i.e., cellulose, sucrose and callose) were analyzed to define the time window and critical duration to the high temperature stress at 34°C(max38°C/min30°C). When developing bolls were subjected to 5 days of high temperature stress at different days post-anthesis(DPA), the changes(Δ%) of fiber length, strength and micronire, as a function of imposed time followed square polynomial eq. as y=a+bx+cx^2, and the time around 15 DPA was the most sensitive period for fiber quality development in response to heat stress. When 15 DPA bolls were heat-stressed for different durations(2, 3, 4, 5, 6, 7 days), the changes(Δ%) of fiber length, strength and micronire, as a function of stress duration followed logistic equations y=A_1-A_2/1+(x/x_0)~p+A_2. Referred to that 5, 10 and 15% are usually used as criteria to decide whether techniques are effective or changes are significant in crop culture practice and reguard to the fiber quality indices change range, we suggested that 5% changes of the major fiber quality indices(fiber length, fiber strength and micronaire) and 10% changes of fiber development components(cellulose, sucrose and callose) could be taken as criteria to judge whether fiber development and fiber quality have been significantly affected by high temperature stress. The key time window for cotton fiber development in response to the high temperature stress was 13–19 DPA, and the critical duration was about 5 days. 展开更多
关键词 cotton(Gossypium hirsutum L.) fiber quality high temperature stress susceptible time window stress endurable duration
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Effect of Lactic Acid Bacteria and Yeast Starter Cultures on the Soaking Time and Quality of “Ofada” Rice 被引量:3
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作者 Oluwafunmilayo Adeniran Olusegun Atanda +1 位作者 Mojisola Edema Olusola Oyewol 《Food and Nutrition Sciences》 2012年第2期207-211,共5页
Freshly harvested paddy rice was randomly obtained from three different farms in “Ofada” town, Ogun State, Nigeria and processed according to the traditional parboiling method. The rice was inoculated singly with cu... Freshly harvested paddy rice was randomly obtained from three different farms in “Ofada” town, Ogun State, Nigeria and processed according to the traditional parboiling method. The rice was inoculated singly with cultures of Lactobacillus amylophilus, Leuconostoc mesenteroides, Saccharomyces uvarum and Saccharomyces cerevisiae which were isolated from the soak-water. In order to assess the effect of starter cultures on the soaking time of the rice, the pH and titratable acidity were determined at 12 h interval. The chemical composition and the sensory quality of the rice were also determined at the end of the soaking period while uninoculated rice served as control. The chemical composition of the rice as well as the pH and TTA of the soak-water were significantly (p < 0.05) different from the control while the processing time was shortened to 48 h. The rice inoculated with Saccharomyces uvarum and Saccharomyces cerevisae had the highest protein content and best sensory attributes. 展开更多
关键词 “Ofada” RICE STARTER CULTURES soak-Water FERMENTATION time QUALITY
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On the Distribution of Duration of First Negative Surplus for a Discrete Time Risk Model with Random Interest Rate
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作者 汪荣明 吴贤毅 《Northeastern Mathematical Journal》 CSCD 2006年第3期299-305,共7页
In this paper, we examine further annuity-due risk model presented by Cai (Probability in the Engineering and Informational Sciences, 16(2002), 309-324). We consider the computation for the distribution of duratio... In this paper, we examine further annuity-due risk model presented by Cai (Probability in the Engineering and Informational Sciences, 16(2002), 309-324). We consider the computation for the distribution of duration of first negative surplus and the algorithm is shown for calculating probability that ruin occurs and the duration of first negative surplus takes any nonnegative integers values. Numerical illustration for the main result is given. 展开更多
关键词 discrete time risk model random interest rate annuity-due risk model duration of negative surplus
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Early Estimation of Strong Aftershock Duration Time
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作者 Zhou Cuiying,Wang Hongwei,Wang Mei,and Zhang YuxiaSeismological Bureau of Shandong Province,Jinan 250014,China Center for Analysis and Prediction,SSB,Beijing 100036,China 《Earthquake Research in China》 1997年第4期35-44,共10页
In order to solve the problem of early estimation of moderately strong aftershock duration time in an earthquake sequence,this study has been conducted.First,the definition of the strong aftershock has been given.It i... In order to solve the problem of early estimation of moderately strong aftershock duration time in an earthquake sequence,this study has been conducted.First,the definition of the strong aftershock has been given.It is pointed out that there is a difference in the strong aftershock duration time between the main shock type sequence and the strong earthquake swarm sequence.After dividing the three cases,i.e.,a strong aftershock duration time larger than 1 day,smaller than 1 day,and no strong aftershock occurred in a main shock type sequence by using the pattern recognition method,we gave the rough correlation relation between strong aftershock duration time and first large shock magnitude for two types of sequences.Finally,the judgment index and method of estimating strong aftershock duration times for different sequence types have been given. 展开更多
关键词 STRONG AFTERSHOCK duration time PATTERN recognition EARLY estimation.
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Minimum colonoscopy observation time for colonic diverticular bleeding: A new benchmark based on the 5% plateau time
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作者 Chikamasa Ichita Tadahiro Goto +2 位作者 Takashi Nishino Soichiro Nakaya Sayuri Shimizu 《World Journal of Gastroenterology》 2025年第40期123-134,共12页
BACKGROUND Colonic diverticular bleeding(CDB)is a leading cause of gastrointestinal blee-ding-related hospitalizations in Japan and is increasingly recognized as a signifi-cant burden in the United States.Identifying ... BACKGROUND Colonic diverticular bleeding(CDB)is a leading cause of gastrointestinal blee-ding-related hospitalizations in Japan and is increasingly recognized as a signifi-cant burden in the United States.Identifying the stigmata of a recent hemorrhage(SRH)during colonoscopy enables targeted hemostasis and reduces rebleeding.However,no benchmark exists for an appropriate observation duration,resulting in operator-dependent variation.Short observation periods may lead to missed SRH,whereas unnecessarily prolonged procedures,particularly in older patients,can increase patient burden and limit endoscopy unit availability.METHODS We retrospectively analyzed patients with acute hematochezia who underwent an initial colonoscopy between January 2017 and December 2024 at a Japanese tertiary hospital.The Observation time was measured from scope insertion to SRH detection(excluding therapeutic time)or withdrawal.The primary outcome,the“5%plateau time”,was defined as the point when the proportion of patients newly identified with SRH in each 5-minute interval consistently dropped below 5%.Computed tomography(CT)-based stratified analyses were performed by endoscopists who conducted≥10%of procedures.RESULTS Of the 1039 patients who underwent colonoscopy,845(mean age 77±11 years;64.5%male)were included.Nine board-certified endoscopists performed the procedures.SRH was detected in 286 patients(33.8%),with a median detection time of 19 minutes(interquartile range,12-28 minutes).The overall 5%plateau time was 40 minutes and varied according to the CT findings:40,35,and 30 minutes for no extravasation,right-sided extravasation,and left-sided extravasation,respectively.This time point corresponded to when 80%-90%of SRH cases were detected.De-spite variations in SRH detection rates and observation durations among endoscopists,the 5%plateau time was consistently approximately 40 minutes.CONCLUSION Although it varied according to the CT findings,the overall 5%plateau time was 40 minutes.This offers a practical benchmark for the minimum observation time without SRH detection. 展开更多
关键词 Diverticular hemorrhage Lower gastrointestinal bleeding Stigmata of recent hemorrhage Observation time Observation duration Withdraw time Bleeding source
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Effect of the Duration Time of the Action Sentence Representation on the Judgment of the Present Time
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作者 Zhang Shilei Ba Xiaona +1 位作者 Xu Peng Lu Zhongyi 《Psychology Research》 2016年第4期220-224,共5页
关键词 持续时间 动作时间 判决 语言理解 认知理论 实验性 句子 参与者
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Effect of Soaking Time on the Mechanical Properties of Annealed Cold-Drawn Low Carbon Steel
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作者 Nurudeen Adekunle Raji Oluleke Olugbemiga Oluwole 《Materials Sciences and Applications》 2012年第8期513-518,共6页
The paper presents the results of investigation on the effect of soaking time on the yield strength, ductility and hardness properties of annealed cold-drawn low carbon steel. The low carbon steel cold-drawn at 40% de... The paper presents the results of investigation on the effect of soaking time on the yield strength, ductility and hardness properties of annealed cold-drawn low carbon steel. The low carbon steel cold-drawn at 40% deformation was annealed at 900 deg Celsius for soaking times of 10, 20, 30, 40, 50 and 60 minutes. Tensile, charpy and Brinnel hardness tests were conducted to determine the yield strengths, tensile strengths, impact strengths, ductility and hardness of the annealed steel with increasing soaking time. The yield strength, tensile strength, hardness and impact strength of the steel showed a continuous drop in value with increasing soaking time up to 60 minutes with a steep drop between 30 and 40 minutes. Ductility values followed the same decreasing trend up to 40 minutes soaking time after which the values started increasing again till 60 minutes soaking time. There was a linear relationship between the tensile strength and hardness of the material for different soaking times. This linear relationship was also observed for yield strength and hardness of the material. 展开更多
关键词 Cold-Drawn ANNEAL soaking-time TENSILE-STRENGTH Yield-Strength Hardness Toughness RECRYSTALLIZATION Grain Growth
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Influence of the quickness and duration of De Qi on the analgesic effect of acupuncture in primary dysmenorrhea patients with a cold and dampness stagnation pattern 被引量:6
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作者 Hu Nijuan Ma Liangxiao +7 位作者 Wang Pei Wu Guiwen Zhao Minyi Hu Shangqing Sun Junjun Wang Yafeng Zhang Zhuang Zhu Jiang 《Journal of Traditional Chinese Medicine》 SCIE CAS CSCD 2019年第2期258-266,共9页
OBJECTIVE: To investigate the influence of the quickness and duration of De Qi(or Qi arrival) on the analgesic effect of acupuncture in primary dysmenorrhea patients with a cold and dampness stagnation pattern.METHODS... OBJECTIVE: To investigate the influence of the quickness and duration of De Qi(or Qi arrival) on the analgesic effect of acupuncture in primary dysmenorrhea patients with a cold and dampness stagnation pattern.METHODS: Sixty-eight patients were randomly assigned to the De Qi group(deep needling with thick needles and manipulation, n = 17) or the non-De Qi group(shallow needling with thin needles and no manipulation, n = 51). Both groups underwent needling at Sanyinjiao(SP 6) for 30 min.The visual analogue scale was used to measure the degree of menstrual pain, and the Acupuncture De Qi Clinical Assessment Scale was used to assess De Qi. Only data from patients who experienced actual De Qi were included in the analysis.RESULTS: Thirty-nine patients experienced actual De Qi. Patients who experienced actual De Qi in the De Qi group(n = 14) felt De Qi more rapidly(P =0.028) and for a longer duration(P = 0.04) than patients who experienced actual De Qi in the non-De Qi group(n = 25). Both groups showed a reduction in the visual analogue scale score for pain after treatment. The analgesic effect did not significantly differ between the two groups. The occurrence time of De Qi showed a significant negative correlation with pain reduction at 20 and 30 min after needle removal(P < 0.05). There was no correlation between the duration of De Qi and the therapeutic effect.CONCLUSION: In primary dysmenorrhea patients with a cold and dampness stagnation pattern,quicker onset of De Qi when needling Sanyinjiao(SP 6) achieves a better analgesic outcome. However, a longer duration of De Qi does not affect the degree of analgesia. Compared with minimal acupuncture, active acupuncture stimulation achieves a more rapid onset and longer duration of De Qi. 展开更多
关键词 Dysmenorrhea COLD-DAMPNESS ACUPUNCTURE ANALGESICS Arrival of QI duration Occurrence time
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Duration-HyTE:基于持续时间建模的时间感知知识表示学习方法 被引量:7
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作者 崔员宁 李静 +3 位作者 沈力 申扬 乔林 薄珏 《计算机研究与发展》 EI CSCD 北大核心 2020年第6期1239-1251,共13页
知识表示学习是知识获取与应用的基础,是贯穿知识图谱构建与应用全过程的重要问题,伴随含有时间标签的大型知识图谱的发展,近几年时间感知的知识表示学习成为该领域研究热点之一.针对传统方法不能有效学习知识持续时长分布规律的问题,... 知识表示学习是知识获取与应用的基础,是贯穿知识图谱构建与应用全过程的重要问题,伴随含有时间标签的大型知识图谱的发展,近几年时间感知的知识表示学习成为该领域研究热点之一.针对传统方法不能有效学习知识持续时长分布规律的问题,融合超平面和有效持续时间建模,提出一种时间感知知识表示学习方法Duration-HyTE.首先,将元事实按照有效持续时间分类,对知识有效持续时间进行建模,提出知识有效可信度的计算方法,将其作用于训练过程评价函数和损失函数的计算,最后在含有时间标签的数据集Wikidata12K、YAGO11K和新建立的持续型关系数据集上进行对比实验,结果表明与其他同类方法相比,Duration-HyTE方法在实体和关系的链接预测和时间预测上性能得到有效提升,尤其在Wikidata12K数据集上,经Duration-HyTE训练得到的知识表示模型对于头尾实体的预测效果比当前最优的表示方法分别提升了25.7%和35.8%,有效提高了链接预测准确率. 展开更多
关键词 知识图谱 持续时间建模 时间感知 知识表示学习 链接预测 有效可信度
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Comparative effectiveness research on incision healing after lumbar spinal surgery with different TDP irradiation durations 被引量:2
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作者 Feng Xiao Ren-Lian Jiang +1 位作者 Jun-Ru Chen Xue-Mei Long 《Frontiers of Nursing》 CAS 2018年第4期273-276,共4页
Objective: This research aims to investigate the best "Te Ding Dian Ci Bo Pu Zhi Liao Qi"(TDP) irradiation duration to enhance the efficacy of nursing and patient satisfaction.Methods: A total of 34 eligible... Objective: This research aims to investigate the best "Te Ding Dian Ci Bo Pu Zhi Liao Qi"(TDP) irradiation duration to enhance the efficacy of nursing and patient satisfaction.Methods: A total of 34 eligible patients were randomly divided into the treatment group(n=18) and the control group(n=16) between December 2015 and December 2016. Qualitative and quantitative studies were combined to create an impersonal evaluation of incision pain score, time of stitches removal, duration of hospital stays, patient satisfaction, and subjective experience due to different TDP irradiation durations.Results: The incision pain scores of the treatment group were 3.06±0.899 and 1.35±0.493 before and after treatment, respectively(P< 0.05), whereas those of the control group were 2.46±1.127 and 1.0±0.707 before and after treatment, respectively(P<0.05).No significant difference was found between the treatment group and the control groupup(P>0.05). The time of stitches removal and the duration of hospital stays of the treatment group were 14.85±4.070 and 19.08±6.652, respectively, whereas those of the control group were 14.08±0.641 and 23.15±10.72(P>0.05), respectively. The patient satisfaction degree score of the treatment group was2.77±0.439, whereas that of the control group was 2.08±0.954(P< 0.05).Conclusions: TDP irradiation can effectively relieve the incision pain of patients after lumbar spinal surgery. The treatment group is superior to the control group in patient satisfaction. 展开更多
关键词 TDP TDP irradiation duration patient satisfaction lumbar operation time incision pain PHYSIOTHERAPY
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Daily Activities and Sleep Durations of Patients with Ischemic Heart Disease Who Were Discharged to Their Homes after Elective Percutaneous Coronary Intervention 被引量:2
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作者 Yuko Yasuhara Tetsuya Tanioka +3 位作者 Rozzano Locsin Waraporn Kongsuwan Beth King Haruo Kobayashi 《Open Journal of Psychiatry》 2017年第4期318-328,共11页
The purpose of this study was to examine the relationship between daily activities and sleep durations for patients following elective percutaneous coronary intervention (ePCI) and diagnosed with ischemic heart diseas... The purpose of this study was to examine the relationship between daily activities and sleep durations for patients following elective percutaneous coronary intervention (ePCI) and diagnosed with ischemic heart disease (IHD) after discharge to their homes. The actigraph data were used to collect data from twenty five patients. The duration of night-time sleep (minutes from the start to end of night-time) and actual night-time sleep duration (total sleep duration excluding wake-up durations of night-time) on the seventh day after discharge were divided into three groups;less than 360, 360 to 480, and more than 480 minutes (short, optimal and long respectively). Subsequently, among the three groups of patients, the data were analyzed by Kruskal Wallis H-test with multiple comparison procedures using the Scheffé-test in order to compare differences in daytime activity items at seven days after discharge from the hospital. Total daytime nap duration (p p p p < 0.05). However, the duration of night-time sleep and daytime activity did not significantly differ. If actual night-time sleep duration is improved from 360 to 480 minutes, daytime nap could potentially be decreased. Determining objective sleep conditions for patients and treating sleep disorders may improve overall patient health, facilitating appropriate sleep and wake rhythms. 展开更多
关键词 ACTIGRAPHY ELECTIVE PERCUTANEOUS CORONARY Intervention Actual Night-time Sleep duration Daily Activity
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Optimization of Injection Timing and Injection Duration of a Diesel Engine Running on Pure Biodiesel SME (Soya Methyl Ester)
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作者 Abdullah Alghafis Eihab A. Raouf 《Open Journal of Applied Sciences》 2020年第7期486-502,共17页
This study was carried out to predict the impact of injection timing and injection duration on engine brake power and Nitrogen Oxides emissions in a diesel engine using biofuel Soya Methyl Ester (SME). Predictions wer... This study was carried out to predict the impact of injection timing and injection duration on engine brake power and Nitrogen Oxides emissions in a diesel engine using biofuel Soya Methyl Ester (SME). Predictions were accomplished at three different injection timings 10<span style="white-space:nowrap;">°</span>, 5<span style="white-space:nowrap;">°</span> Crank Angle (CA) before Top Dead Center (bTDC) and 0<span style="white-space:nowrap;">° </span>CA at Top Dead Center (TDC) and four injection durations 20<span style="white-space:nowrap;">°</span>, 25<span style="white-space:nowrap;">°</span>, 30<span style="white-space:nowrap;">°</span>, 35<span style="white-space:nowrap;">°</span> CA. The study was conducted using a simulation software (Diesel-RK). The predicted results showed that the power<span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> produced by all the setups of the different injection timings </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">are</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> almost equal, but they differ in injection durations, e.g. the power at setup (10<span style="white-space:nowrap;">°</span> CA</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">bTDC) duration 20<span style="white-space:nowrap;">°</span> CA and 2500 rpm equal to 52 kW, at setup (5<span style="white-space:nowrap;">°</span> CA</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">bTDC) duration 25<span style="white-space:nowrap;">° </span>CA and same engine speed the power is equal to 51 kW, and at setup (0<span style="white-space:nowrap;">°</span> CA</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">TDC) durations 30<span style="white-space:nowrap;">°</span> the power is equal to 51 kW. The power in all setups are decreased as the injection duration increased, e.g. at setup 0<span style="white-space:nowrap;">°</span> CA TDC durations 25<span style="white-space:nowrap;">°</span>, 35<span style="white-space:nowrap;">°</span>, and 40<span style="white-space:nowrap;">°</span> CA and at 4000 rpm, the brake powers are equal 71, 65, and 59 kW respectively, thus the reduction percentages are 9% and 17% when compared to the 25<span style="white-space:nowrap;">°</span> injection duration. The nitrogen oxides emissions decreased as the injection duration is increased, e.g. the emissions at setup (10<span style="white-space:nowrap;">°</span> CA</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">bTDC) durations 25<span style="white-space:nowrap;">°</span>, 30<span style="white-space:nowrap;">°</span>, and 40<span style="white-space:nowrap;">°</span> CA and at 2500 rpm are equal 852, 589, 293 ppm respectively, the reduction percentages are 30% and 72%. The variations of injection timing and injection duration </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">have </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">taken a weighty influence on engine performance and emissions. The results </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">are</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> considered as a novelty in the field of using pure biofuel Soya Methyl Ester in diesel engine according to our information.</span></span></span> 展开更多
关键词 Pure Biofuel Soya Methyl Ester Diesel Engine Injection Timing Injection duration Optimization
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Effect of Raman-pulse duration related to the magnetic field gradient in high-precision atom gravimeters
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作者 Yuan Cheng Yu-Jie Tan +3 位作者 Min-Kang Zhou Xiao-Chun Duan Cheng-Gang Shao Zhong-Kun Hu 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第3期137-145,共9页
The effect of the Raman-pulse duration related to the magnetic field gradient, as a systematic error, is playing an important role on evaluating the performance of high-precision atomic gravimeters. We study this effe... The effect of the Raman-pulse duration related to the magnetic field gradient, as a systematic error, is playing an important role on evaluating the performance of high-precision atomic gravimeters. We study this effect with a simplified theoretical model of the time-propagation operator. According to the typical parameters, we find that this effect should be taken into account when the gravimeter reaches an accuracy of 10^-10g, and the larger the pulse duration is, the more obvious the systematic effect will be. Finally, we make a simple discussion on the possibility of testing this effect. 展开更多
关键词 atom gravimeters magnetic field gradient Raman-pulse duration time-propagation operator
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考虑决策者时长偏好的分时电价时段划分 被引量:1
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作者 李艳梅 顾诚凯 +2 位作者 任恒君 司戈 李一唯 《电力工程技术》 北大核心 2025年第3期131-139,共9页
时段划分是制定分时电价的重要环节,每个时段中的最小连续时长与最大连续时长对分时电价的调整效果有重要影响,但目前关于分时电价时段划分的研究鲜有考虑决策者的时长偏好。因此文中考虑决策者对时段总时长、时段内最小连续时长和时段... 时段划分是制定分时电价的重要环节,每个时段中的最小连续时长与最大连续时长对分时电价的调整效果有重要影响,但目前关于分时电价时段划分的研究鲜有考虑决策者的时长偏好。因此文中考虑决策者对时段总时长、时段内最小连续时长和时段内最大连续时长的不同需求,在聚类分析的基础上,构建考虑决策者偏好的分时电价时段划分模型。所提模型通过隶属度函数和欧氏距离计算负荷值之间的距离,并以各簇内相似性总和最小为目标函数。使用中国某地区的典型日负荷数据验证所提模型的合理性和有效性,结果显示,该模型可以得出满足决策者偏好的时段划分结果。研究发现,采用0-1整数线性规划对时间段进行聚类分析是解决决策者持续时间偏好问题的有效方法。在传统分时电价时段划分模型下,存在修正后的负荷与时段电价不符的现象,而文中所提考虑决策者时长偏好的分时电价时段划分模型对该现象有显著的纠偏效果。 展开更多
关键词 时段划分 分时电价 决策者时长偏好 最小连续时长 最大连续时长 聚类分析
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油莎豆种子萌发特性对不同浸种时间的响应研究
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作者 闫建国 柳振宇 +2 位作者 刘飞 包海柱 王诗瑶 《安徽农业科学》 2025年第20期22-26,32,共6页
[目的]探究浸种时间对油莎豆种子萌发的影响并确定其最适宜时长。[方法]设置0(CK)、24、48和72 h共4个浸种时间梯度,通过光照培养室盆栽试验测定种子的出苗率及相关性状。[结果]单因素方差分析表明,浸种时间对油莎豆种子的萌发及根芽性... [目的]探究浸种时间对油莎豆种子萌发的影响并确定其最适宜时长。[方法]设置0(CK)、24、48和72 h共4个浸种时间梯度,通过光照培养室盆栽试验测定种子的出苗率及相关性状。[结果]单因素方差分析表明,浸种时间对油莎豆种子的萌发及根芽性状指标影响显著(P<0.05)。与对照组相比,浸种24、48和72 h均能显著提高种子萌发率,其中以48 h处理的效果最佳,各项萌发与生长指标均达到峰值。当浸种时间超过48 h后,各指标呈下降趋势,表现出抑制效应。出苗率测定结果进一步验证,浸种48 h最利于油莎豆出苗。[结论]浸种48 h为油莎豆种子的最适浸种时间。研究结果可为缩短油莎豆育苗周期、提高田间成苗质量提供重要的理论依据与技术支持。 展开更多
关键词 油莎豆 浸种时间 种子 萌发指标
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近十年针刺频次与疗程的研究现状及其量效规律
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作者 罗钦 孙铭声 +7 位作者 田昊 徐桂兴 杨春滟 黄柳杨 李茜 刘亦琳 冀来喜 梁繁荣 《世界中医药》 北大核心 2025年第2期266-274,共9页
目的:通过总结近10年针刺刺激量研究现状,分析针刺频次、疗程的量效规律特征,为临床针刺时间参数选择提供参考。方法:检索2013年3月至2023年3月PubMed、Embase、Scopus、国家知识基础设施数据库(CNKI)、中国学术期刊数据库(CSPD)以及中... 目的:通过总结近10年针刺刺激量研究现状,分析针刺频次、疗程的量效规律特征,为临床针刺时间参数选择提供参考。方法:检索2013年3月至2023年3月PubMed、Embase、Scopus、国家知识基础设施数据库(CNKI)、中国学术期刊数据库(CSPD)以及中文科技期刊数据库(CCD)的针刺频次、疗程量效研究相关文献,按疾病类别及其临床分期对针刺优次时间剂量、起效时间剂量等进行汇总分析。结果:共纳入62篇临床研究;“针刺频率”“疼痛”“慢性期”关注较多。针刺频率:在一定疗程内,疗效与针刺频率正相关,提高针刺频率可更快起效;低频针刺起效较缓,但同次数长疗程时疗效更优。在特定疗程,疗效可能与针刺频率(≥2次/周)无关。疾病临床分期不同,其最优针刺频率存在差异,特发性面神经炎急性期宜≥3次/周,缺血性卒中亚急性期宜≥5次/周,慢性疾病稳定期宜3~4次/周。针刺疗程、次数:慢性期针刺疗程较急性、亚急性期长;疼痛、妇科疾病多在1~2周、2~6次针刺起效,而神经受损、复杂内科疾病则需超4周、10次以上针刺起效。结论:针刺宜以中高频率快速取效,达到效应峰值后,以低频率针刺延长疗程稳固疗效;不同疾病起效、最优时间剂量存在差异,同临床分期的不同疾病最优针刺频率存在共性。 展开更多
关键词 针刺 量效规律 针刺次数 针刺频率 针刺疗程 疼痛 临床分期 文献分析
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刺网布放时长与时段组合对莱州湾渔获物组成的影响
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作者 李忠义 王惠宾 韩青鹏 《广东海洋大学学报》 北大核心 2025年第5期19-25,共7页
【目的】评估刺网布放时长与时段数不同组合对刺网渔获物组成的影响,为建立莱州湾刺网调查作业的最佳布放时间模式提供依据,并为近岸渔业资源刺网调查标准化提供支撑。【方法】在莱州湾西北部水域,开展总时长12 h(17:30―5:30),分时长... 【目的】评估刺网布放时长与时段数不同组合对刺网渔获物组成的影响,为建立莱州湾刺网调查作业的最佳布放时间模式提供依据,并为近岸渔业资源刺网调查标准化提供支撑。【方法】在莱州湾西北部水域,开展总时长12 h(17:30―5:30),分时长与时段数3种不同组合的刺网调查,统计分析渔获率及物种组成差异。分组为A组,分3个时段每个时段4 h,布放在不同采样区域(4 h×3);B组,连续12 h布放在同一采样区域(12 h×1);C组,分4个时段每个时段3 h,布放在不同采样区域(3 h×4)。【结果】3种模式均能捕获调查水域主要资源种类,但4 h×3能覆盖更多资源种类,各时段间群落种类相似系数范围为0.47~0.70,远高于3 h×4分段模式的0.18~0.53。F_(r)iedman非参数检验显示,4 h×3各时段质量与数量渔获率具有时序异质性(F_(r)=7.97,7.25;P=0.02,0.03),而3 h×4各时段渔获率无统计学差异(F_(r)=0.17~1.21,P=0.24~0.90),能更真实反映群落结构组成。Wilcoxon秩和检验表明,4 h×3的质量与数量渔获率都极显著高于12 h×1和3 h×4(P<0.01),说明4 h×3可提高渔获率,缓解捕获累积效应。ANOSIM相似性分析表明,3种模式间群落质量与数量结构均差异极显著(R=1,P<0.01),4 h×3与其他两组的组间整体结构差别大于物种个体层面差异;12 h×1与3 h×4组间差异主要依赖独有物种的贡献,表明4 h×3群落组成更具水域代表性。两种分段模式各自时段间群落质量与数量结构的整体差异显著(R=0.79~0.86,P=0.001~0.030),且两两间差异均显著(P<0.05),时序异质性突出,17:30―21:30和2:30―5:30分别是其时序差异的核心时段。【结论】建议将涵盖昼夜交替时段的4 h×3组合作为基础调查方案,后续应开展多时间梯度长期对比监测,调整建立不同海域最佳布放时长与时段数组合。 展开更多
关键词 刺网 渔获物 渔业资源调查 时长 时段 莱州湾
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