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VOLUMETRIC-SWEPT DISPLAY SYSTEM BASED ON HELIX ROTATING SCREEN AND DMD
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作者 岳键 赵晓庚 +2 位作者 邢建芳 潘文平 沈春林 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2011年第4期367-371,共5页
Based on the helix rotating screen and the digital micro-mirror device (DMD), the former proto of volumetric-swept display system is improved. The 3-D display system adopting a helix rotating screen to construct an ... Based on the helix rotating screen and the digital micro-mirror device (DMD), the former proto of volumetric-swept display system is improved. The 3-D display system adopting a helix rotating screen to construct an imaging space meliorate the defects, such as the smaller image space, the fewer voxels and the severer voxel overlap dead zone caused by planar rotating screen. DMD with spatial light modular (SLM) technology increases the transmission bandwidth of 3-D data in the voxel activation subsystem and activate multi-voxel once time. The volumetric-swept system based on helix rotating screen and DMD is developed. The experimental results show that the image space, the vision dead zone, the voxels on slice, and the voxel activation capacity of the designed proto are superior to the plane rotating screen system. 展开更多
关键词 true 3-D display volumetric 3-D display volumetric-swept display helix rotating screen digital micro-mirror device (DMD)
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Twelve weeks of dance exergaming in overweight and obese adolescent girls:Transfer effects on physical activity,screen time,and self-efficacy 被引量:9
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作者 Amanda E.Staiano Robbie A.Beyl +2 位作者 Daniel S.Hsia Peter T.Katzmarzyk Robert L.Newton Jr 《Journal of Sport and Health Science》 SCIE 2017年第1期4-10,127,共8页
Background: Given the low levels of physical activity(PA) among adolescent girls in the US, there is a need to identify tools to motivate increased PA. Although there is limited evidence that adolescents transfer PA f... Background: Given the low levels of physical activity(PA) among adolescent girls in the US, there is a need to identify tools to motivate increased PA. Although there is limited evidence that adolescents transfer PA from one context to another, exergames(i.e., video games that require gross motor activity) may act as a gateway to promote overall PA outside game play. The purpose of this study was to examine potential transfer effects(i.e., influences on external behaviors and psychological constructs) of a 12-week exergaming intervention on adolescent girls' PA, screen time,and self-efficacy toward PA, as well as the intrinsic motivation of exergaming.Methods: Participants were 37 girls aged 14–18 years(65% African American, 35% white) who were overweight or obese(body mass index ≥ 85 th percentile) and were recruited from the community via school, physicians, news media, and social media websites. Adolescents were randomly assigned to a 12-week group exergaming intervention(thirty-six 60 min sessions of group-based dance exergaming in a research laboratory using Kinect for Xbox360(Microsoft Corporation, Redmond, WA, USA)) or to a no-treatment control group. Outcome variables included objectively measured PA(total) and self-reported leisure-time PA(discretionary time only) 1 week before vs. 1 week after the intervention; selected type and intensity of PA when placed in a gym setting for 30 min("cardio free choice"); screen time; self-efficacy toward PA; and intrinsic motivation toward exergaming.Results: Attendance at the exergaming sessions was high(80%). Compared with the control group, the intervention group self-reported an increase in PA(p = 0.035) and fewer hours watching television or videos(p = 0.01) after the intervention, but there were no significant differences in sedentary, light, moderate, or vigorous PA measured by accelerometry. The intervention group significantly improved self-efficacy toward PA(p = 0.028). The intervention group highly rated intrinsic motivation toward exergaming.Conclusion: Exergaming for 12 weeks was associated with positive impacts on adolescent girls' self-reported PA, television viewing, self-efficacy,and intrinsic motivation. Future research is warranted to leverage exergames as an enjoyable, motivating, and effective PA tool. 展开更多
关键词 Active video games Leisure activity Motivation screen time SELF-EFFICACY Television
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Physical activity, screen time and pediatric health-related quality of life in the Mississippi Delta 被引量:3
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作者 Tamara T. Perry Page C. Moore +2 位作者 Karen M. Redwine James M. Robbins Judith L. Weber 《Open Journal of Preventive Medicine》 2012年第1期105-111,共7页
Background: The association of physical activity (PA) and screen time (ST) on health-related quality of life (HRQOL) among predominantly low-income children in the Mississippi Delta region has not been previously desc... Background: The association of physical activity (PA) and screen time (ST) on health-related quality of life (HRQOL) among predominantly low-income children in the Mississippi Delta region has not been previously described. Methods: We performed a cross-sectional survey to assess health risks from a representative sample of the population ≥3 years old in the Delta Region of Arkansas, Louisiana, and Mississippi. Linear models were utilized to examine Pediatric Quality of Life Inventory (PedsQL) scores based on reported PA and ST. Results: Median age of the 371 participants was 9.8 years, 57% were African American, and 26% had annual household income ≤$14,999. Overall, 262 (75%) were categorized as physically active and 48% reported >2 hours ST per day. Children reporting exercising 5 - 7 days per week had significantly better PedsQL total score (84.3 vs 80.8;p 2 hours per day) did not significantly impact HRQOL. Conclusions: Findings suggest that PA among children living in the Mississippi Delta was related to higher HRQOL;however, the positive effects of PA on HRQOL may be less for minority and low-income children. 展开更多
关键词 PHYSICAL ACTIVITY screen time Quality of LIFE PEDIATRICS
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Association between tear film break up time and blink interval in visual display terminal users 被引量:6
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作者 Miki Uchino Motoko Kawashima +2 位作者 Yuichi Uchino Kazuo Tsubota Norihiko Yokoi 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2018年第10期1691-1697,共7页
AIM:To investigate the association between tear film break up time(TBUT)and blinking interval in visual display terminal(VDT)users.METHODS:Nine hundred and thirty VDT users underwent dry eye testing,and function... AIM:To investigate the association between tear film break up time(TBUT)and blinking interval in visual display terminal(VDT)users.METHODS:Nine hundred and thirty VDT users underwent dry eye testing,and functional visual acuity(FVA)test.The blinking interval during FVA was compared with TBUT.Subjects with longer blinking interval than TBUT were considered as unstable tear film.Logistic regression analysis revealed the risk factors for unstable tear group.RESULTS:Among 930 workers,858 subjects(92.3%)participated in this study.Almost 80% of the subjects were categorized into the unstable tear group.Unstable tear group has significantly lower Schirmer values and TBUT(17.5±11.6 vs 21.1±11.5 mm,3.7±2.6 vs 5.7±2.7s,both P〈0.001).There were no significant differences in epithelial staining or severity of symptoms.Logistic regression showed that over 40y was a risk for being unstable tear group[odds ratio(OR)=1.53;95%confidence interval(CI)=1.06-2.20].Contact lens use was protective factor for being in the unstable tear group(OR=0.37;95%CI=0.26-0.53).CONCLUSION:Subjects with shorter TBUT than blinking interval are prevalent among VDT users.Subjects over the age of 40 shows an increased risk for unstable tear film. 展开更多
关键词 dry eye disease blink interval tear film break up time visual display terminal use
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Fundamental motor skills,screen-time,and physical activity in preschoolers 被引量:15
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作者 E.Kipling Webster Corby K.Martin Amanda E.Staiano 《Journal of Sport and Health Science》 SCIE 2019年第2期114-121,共8页
Purpose: To examine the associations among preschoolers fundamental motor skills, screen-time, physical activity(PA), and sedentary behavior(SB).Methods: Children ages 3à4 years were enrolled in a prospective obs... Purpose: To examine the associations among preschoolers fundamental motor skills, screen-time, physical activity(PA), and sedentary behavior(SB).Methods: Children ages 3à4 years were enrolled in a prospective observational trial of PA. Trained assessors conducted the Test of Gross Motor Development-3 rd edition(TGMD-3), and the Movement Assessment Battery for Children-2 nd edition, and parent-reported child screen-time and sociodemographic information. Children wore an accelerometer for 7 days to examine SB and total PA(TPA). TPA was further characterized as moderateto-vigorous PA(MVPA) or vigorous PA(VPA). Mixed linear models were calculated, controlling for age(for TGMD-3), sex, household income, and accelerometer wear time(for accelerometry models), with childcare center as a random effect. The primary analysis reported on the cross-sectional baseline data of 126 children with complete fundamental motor skill and screen-time data; a subanalysis included 88 children with complete accelerometry data.Results: Children were 3.4 § 0.5 years of age(54% girls; 46% white, 42% African American, 12% other). A total of 48% lived in households at or below the federal poverty level. Children engaged in 5.1 § 3.6 h/day of screen-time. Children's screen-time was inversely related to the Movement Assessment Battery for Children-2 nd edition, manual dexterity skills percentile(b(SE) = ?1.7(0.8), p = 0.049). In the accelerometry subsample,children engaged in 5.9 § 0.9 h/day of TPA of which 1.7 § 0.6 h/day was MVPA. Boys engaged in more MVPA and VPA and less SB compared with girls(all p < 0.05). A higher TGMD-3, total score(b(SE) = 0.4(0.2), p = 0.017) and locomotor score(b(SE) = 0.7(0.3), p = 0.018) were associated with more VPA but not with TPA or MVPA. Screen-time and television in the bedroom were not related to SB, TPA, MVPA, or VPA.Conclusion: Children's motor skills were positively related to VPA but inversely related to screen-time. Further inquiry into the implications of high exposure to screen-time in young children is needed. 展开更多
关键词 FUNDAMENTAL motor SKILLS Physical activity PRESCHOOL screen-time
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Screening and reconstruction of real-time traffic data 被引量:1
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作者 裴玉龙 马骥 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2003年第1期1-6,共6页
The quality of real time traffic information is of the great importance, therefore the factors having effect on traffic characteristics are analyzed in general, and the necessities of real time data processing are sum... The quality of real time traffic information is of the great importance, therefore the factors having effect on traffic characteristics are analyzed in general, and the necessities of real time data processing are summarized. The identification and reconstruction of real time traffic data are analyzed using Kalman filter equation and statistical approach. Four methods for ITS (Intelligent transportation system) detector data screening in traffic management systems are discussed in detail. Meanwhile traffic data examinations are discussed with solutions formulated through analysis, and recommendations are made for information collection and data management in future. 展开更多
关键词 real time traffic data ITS screenING RECONSTRUCTION
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Examining Screen Time, Screen Use Experiences, and Well-Being in Adults
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作者 Tracy Liran Wang Dianne A. Vella-Brodrick 《Social Networking》 2018年第1期32-44,共13页
Screen technologies have been found to have adverse outcomes on people’s well-being and mental health if used excessively however findings have varied depending on the screen type being assessed. The impact of prolon... Screen technologies have been found to have adverse outcomes on people’s well-being and mental health if used excessively however findings have varied depending on the screen type being assessed. The impact of prolonged TV-watching on mental health has been well established, whereas the influence of computers, the internet, and mobile phones is still being debated. Research exploring total screen use in adults is surprisingly lacking. The current study examined the relationship between Screen Time and well-being in adults, including positive relationships, meaning, and loneliness. The study is possibly the first to investigate how much pleasure and meaning people feel during screen use and their mediating effects. Using a correlational study design, participants (N = 139) reported their hours spent on all screen devices per day, how much pleasure and meaning they experience during screen use on average, and their general well-being levels. Screen Time was not found to be significantly correlated with well-being;and screen use experiences did not mediate any of the screen time and well-being relationships. However, screen use meaning was positively associated with overall well-being and positive relationships. This finding prompts a review of the importance of screen time for well-being, suggesting that this may be a limited approach. Other factors related to screen quality may be equal if not more important for well-being. Limitations and implications for maintaining or enhancing well-being while using screen devices are discussed. 展开更多
关键词 screen time screen USE Experiences WELL-BEING PERMA RELATIONSHIPS LONELINESS
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Specific Types of Screen-Based Sedentary Time and Depressive Symptoms in Adolescents
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作者 Shande Liu 《International Journal of Mental Health Promotion》 2022年第4期491-501,共11页
Purpose:Screen-based sedentary behavior(SSB)has been identified as risk factor for mental disorders in most of adolescents.However,there is little literature pertaining to the specific kinds of SSB and its connections w... Purpose:Screen-based sedentary behavior(SSB)has been identified as risk factor for mental disorders in most of adolescents.However,there is little literature pertaining to the specific kinds of SSB and its connections with depressive symptoms in most of adolescents.In the present study,we are going tofind out the connections between specific types of SSB and depressive symptoms in Chinese adolescents.Methods:A cross-sectional data based on 996 study participants of middle school students in Guangdong Province.SSB was evaluated by distri-buting the questionnaire of Health Behavior in School-aged Children,while depressive symptoms were evaluated using Chinese version of Children’s Depressive symptoms Inventory(CDI).SSB was categorized into TV/movie time,video games time and other electronic devices-based time(e.g.,mobile phone,computer use).Generalized linear models was used to explore the connections between specific kinds of SSB and depressive symptoms.Results:After controlling for variables of sex,ethnicity,grade,residence,siblings,perceived family affluence,father educational level,mother educational background,body mass index(BMI),physical exercise,duration of sleep,other electronic devices-based time was positively correlated with depressive symptoms in Chinese adolescents(B=0.557%,95%CI:0.187–0.926,p=0.003).This significant connection was also found in girls(B=0.728%,95%CI:0.230–1.225,p=0.004)instead of boys(p>0.05).The other types of SSB were not signifi-cantly in relation to depressive symptoms in adolescents regardless of sex.Conclusion:This study suggested that it might be effective in reducing or preventing depressive symptoms through limiting electronic devices-based time,like computer use or mobile phone use time.This strategy would be particularly useful in girls.Future stu-dies should negate or replicate the research results by introducing more improved study design,which is beneficial to better understand the connections between SSB and depressive symptoms as well as then design more efficient interventions in adolescents. 展开更多
关键词 screen time TYPES middle school students DEPRESSION
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Association of Physical Activity, Screen Time and Sleep with Depressive Symptoms in Adolescents
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作者 Qiang Sun Xuzhi Zhan 《International Journal of Mental Health Promotion》 2021年第1期75-86,共12页
Little is known on the association between movement behaviors including physical activity(PA),screen time(ST)and sleep(SLP)with depression in adolescents.This study aimed to explore the associations of PA,ST and SLP w... Little is known on the association between movement behaviors including physical activity(PA),screen time(ST)and sleep(SLP)with depression in adolescents.This study aimed to explore the associations of PA,ST and SLP with depressive symptoms in adolescents.A total of 1,331 middle school students participated in this survey and provided valid data pertaining to the study variables.Self-reported questionnaires were used to collect information on participants’sociodemographic parameters.The Health Behavior in School-aged Children Questionnaire was used to assess the PA(days for moderate to vigorous PA),ST(daily hours of ST)and SLP(daily hours of SLP).Study participants’depressive symptoms were assessed using the Children’s Depression Inventory.Generalized linear models were used to estimate the associations of PA,ST and SLP with depressive symptoms.Of all the 1331 study participants,boys accounted for 51.31%and percentage of 7th,8th and 9th graders were 52.44%,23.22%and 24.34%,respectively.After controlling for sex,body mass index,grade,ethnicity,residence,siblings,perceived family affluence,father and mother educational level,only ST was positively associated with depressive symptoms(beta=0.17,p=0.005).This study suggests that excessive ST would be detrimental to depressive symptoms in adolescents.It may be effective to reduce ST for depression intervention or prevention.Future studies are encouraged to use an improved study design to confirm or negate this study’s researchfindings. 展开更多
关键词 Moderate to vigorous physical activity screen time SLEEP DEPRESSION middle school students
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Momentum Eigensolutions of Feinberg-Horodecki Equation with Time-Dependent Screened Kratzer-Hellmann Potential 被引量:1
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作者 Mahmoud Farout Sameer M. Ikhdair 《Journal of Applied Mathematics and Physics》 2020年第7期1207-1221,共15页
We obtain an approximate value of the quantized momentum eigenvalues, <em>P<sub>n</sub></em>, together with the space-like coherent eigenvectors for the space-like counterpart of the Schr<sp... We obtain an approximate value of the quantized momentum eigenvalues, <em>P<sub>n</sub></em>, together with the space-like coherent eigenvectors for the space-like counterpart of the Schr<span style="white-space:nowrap;">&#246;</span>dinger equation, the Feinberg-Horodecki equation, with a screened Kratzer-Hellmann potential which is constructed by the temporal counterpart of the spatial form of this potential. In addition, we got exact eigenvalues of the momentum and the eigenstates by solving Feinberg-Horodecki equation with Kratzer potential. The present work is illustrated with three special cases of the screened Kratzer-Hellman potential: the time-dependent screened Kratzer potential, time-dependent Hellmann potential and, the time-dependent screened Coulomb potential. 展开更多
关键词 Coherent States Feinberg-Horodecki Equation time-Dependent screened Kratzer-Hellmann Potential time-Dependent Kratzer Potential time-Dependent Yukawa Potential time-Dependent Hellmann Potential time-Dependent Coulomb Potential
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Screening for Plant Toxins in Honey and Herbal Beverage by Ultrahigh-Performance Liquid Chromatography-Ion Mobility-Quadrupole Time of Flight Mass Spectrometry
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作者 Qiaozhen Guo Yi Yang +2 位作者 Jiang Li Bing Shao Jing Zhang 《American Journal of Analytical Chemistry》 2022年第3期108-134,共27页
The standards of plant toxins were separated by a C18 column with gradient elution with 0.1% formic acid/water (V/V) and 0.1% formic acid/acetonitrile (V/V) as mobile phase and acquired by ion mobility-quadrupole time... The standards of plant toxins were separated by a C18 column with gradient elution with 0.1% formic acid/water (V/V) and 0.1% formic acid/acetonitrile (V/V) as mobile phase and acquired by ion mobility-quadrupole time of flight mass spectrometry (IM-QTOF MS) in positive ion mode. A database of 308 plant toxins including retention time, collision cross-section (CCS) and its fragment ions was established. Honey dissolved in water or herbal beverage was extracted by acetonitrile and purified with PSA sorbent, and then acquired by ultrahigh-performance liquid chromatography IM-QTOFMS. The acquired data were processed by comparing with the database we established to confirm the target compounds. The average recoveries for samples at two levels ranged from 60.6% - 120.1%, with relative standard deviation (n = 6) less than 25%. The limit of quantitation for plant toxins ranged from 1 - 20 μg/kg. The developed screening method was used in determination of honey, herbal beverage and honey flavored tea beverage samples. The results showed that berberine was detected in one honey with 1 μg/kg and caffeine was present in some beverages with the concentration from 200 and 5500 μg/kg. This method could meet the requirement for rapid screening of plant toxins in honey and herbal beverage. It can be used for the quality control of honey and herbal beverage in enterprises or quality inspection departments. It also can be used in the rapid screening of food poisoning. 展开更多
关键词 screenING Plant Toxins HONEY Herbal Beverage Ultrahigh-Performance Liquid Chromatography ion Mobility-Quadrupole time of Flight Mass Spectrometry
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人工智能宫颈癌实时筛查系统TruScreen在宫颈癌筛查中的作用研究 被引量:4
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作者 刘航 兰翀 +1 位作者 刘志辉 牛菊敏 《生殖医学杂志》 CAS 2023年第8期1177-1184,共8页
目的探讨人工智能宫颈癌实时筛查系统TruScreen(TS)在宫颈癌筛查中的临床应用价值。方法回顾性分析2019年12月至2020年12月于我院妇科门诊进行宫颈癌筛查的997例受检对象的临床资料,所有研究对象均进行了TS检测、人乳头瘤病毒(HPV)检测... 目的探讨人工智能宫颈癌实时筛查系统TruScreen(TS)在宫颈癌筛查中的临床应用价值。方法回顾性分析2019年12月至2020年12月于我院妇科门诊进行宫颈癌筛查的997例受检对象的临床资料,所有研究对象均进行了TS检测、人乳头瘤病毒(HPV)检测、液基薄层细胞学(TCT)检测。3种筛查方法中有任何1种异常者行阴道镜检查,阴道镜下有病变的患者均行宫颈活检。以组织病理学结果为诊断标准,比较3种方法单独筛查及TS+HPV联合筛查、TCT+HPV联合筛查的灵敏度、特异度、阳性预测值、阴性预测值及受试者工作特征曲线下面积(AUC)。结果纳入的997例受检对象平均年龄(35.42±8.47)岁。131例患者行宫颈活检术,病理结果异常[低级别鳞状上皮内病变(LSIL)及以上]共59例,其中TS检测阳性率为86.44%(51/59),HPV检测阳性率为94.92%(56/59),TCT检测阳性率为89.83%(53/59)。以组织病理结果[高级别鳞状上皮内病变(HSIL)及以上]为标准,TS检测的灵敏度为88.24%、特异度为58.76%,AUC为0.735;TCT检测的灵敏度为47.06%、特异度为70.10%,AUC为0.586;HPV检测的灵敏度为94.12%、特异度为36.08%,AUC为0.651;TS+HPV联合检测的灵敏度为97.06%、特异度为87.63%,AUC为0.588;TCT+HPV联合检测的灵敏度为91.18%、特异度为98.96%,AUC为0.598。结论TS检测用于宫颈癌筛查有较好的效果,具有一定的临床应用价值。 展开更多
关键词 人工智能宫颈癌实时筛查系统 液基薄层细胞学检测 人乳头瘤病毒检测 宫颈癌筛查 宫颈活检
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The Development of Time-of-flight Mass Spectrometry( TOF-MS) and Its Applications in Screening Food Hazard Factors
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作者 Lei WANG Lixue DONG +4 位作者 Yi LI Huihui CAO Yanhua YAN Ruihuan DU Aijun LI 《Agricultural Biotechnology》 CAS 2020年第2期101-104,共4页
The time-of-flight mass spectrometry(TOF-MS),one of the mass spectrometry techniques,has been widely applied in the field of rapid screening of food hazard factors as a superior analysis technique because of its wide ... The time-of-flight mass spectrometry(TOF-MS),one of the mass spectrometry techniques,has been widely applied in the field of rapid screening of food hazard factors as a superior analysis technique because of its wide mass range,high resolution and mass measurement accuracy,high sensitivity and high analysis speed.In this paper,research progresses of TOF-MS on the detection of food additives,food contaminants and residues,illegal additives,pesticide residues,veterinary drug residues and mycotoxin were reviewed,and its probable approaching applications were prospected. 展开更多
关键词 time-OF-FLIGHT mass SPECTROMETRY FOOD HAZARD FACTOR screenING Application
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青少年静态行为与抑郁症状的相关性研究
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作者 孙洁丽 郭亚茹 《体育学刊》 CAS 北大核心 2024年第5期68-74,共7页
探究静态行为与青少年抑郁症状之间的关系,为改善和预防青少年抑郁提供相关理论依据。于2021年9—12月在上海、昆明、乌鲁木齐、宿州与长沙采取分层整群随机抽样抽取10327名12~17岁青少年进行静态行为调查与抑郁症状评估,采用卡方检验... 探究静态行为与青少年抑郁症状之间的关系,为改善和预防青少年抑郁提供相关理论依据。于2021年9—12月在上海、昆明、乌鲁木齐、宿州与长沙采取分层整群随机抽样抽取10327名12~17岁青少年进行静态行为调查与抑郁症状评估,采用卡方检验、逻辑回归分析探讨两者关系。结果显示:青少年抑郁总检出率为28.6%,其中抑郁症状、严重抑郁总检出率分别为19.5%、9.1%。高中生抑郁检出率高于初中,女生检出率高于男生。控制相关影响因素后,静态行为时长≥8h、视屏时间≥2h组的青少年抑郁症状检出率分别为静态行为时长<8h、视屏时间<2h组的1.302和1.348倍(P<0.01)。研究表明:静态行为尤其是视屏时间与青少年抑郁症状密切相关。应当重视静态行为对青少年身心健康造成的危害,通过设定合理的使用时间、鼓励参与户外活动、教育正确的使用习惯、家长监督和参与等措施限制静态行为和视屏时间,引导青少年正确使用电子设备,以减少和预防青少年抑郁症状的发生。 展开更多
关键词 青少年 抑郁症状 静态行为 视屏时间
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综合干预对儿童视屏时间影响的研究
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作者 王璐 段宇祺 +3 位作者 岳芷涵 吕瑾莨 王辉 王海俊 《中国妇幼健康研究》 2024年第7期12-16,共5页
目的分析综合干预项目(DECIDE-children)对儿童视屏时间的影响及可能的中介因素,为控制儿童视屏时间提供依据。方法于2018年9月至2019年6月,在北京、山西、新疆的24所小学进行整群分层随机抽样,纳入1392名四年级学生,以1∶1的比例分为... 目的分析综合干预项目(DECIDE-children)对儿童视屏时间的影响及可能的中介因素,为控制儿童视屏时间提供依据。方法于2018年9月至2019年6月,在北京、山西、新疆的24所小学进行整群分层随机抽样,纳入1392名四年级学生,以1∶1的比例分为干预组或对照组,干预组儿童开展为期一学年的饮食运动行为综合干预,对照组参加常规教学。使用基线和终期随访问卷调查儿童视屏时长和运动与视屏知识、家长对儿童视屏时间的限制相关指标。使用线性回归及广义线性回归模型进行关联研究,非参数百分位Bootstrap法检验中介效应,调整基线调查的年龄和性别。结果在1392名调查对象中,基线调查时视屏时间≥2h/d的儿童有289人(20.8%)。与基线结果相比,终期干预组中家长限制儿童视屏时间不超过2h/d的比例、儿童的运动与视屏知识满分率增加大于对照组(OR_(adj)=1.64、2.27);儿童视屏时间≥2h/d的比例减少大于对照组(OR_(adj)=0.57)(均P<0.05)。中介效应检验结果显示,家长限制儿童视屏时间不超过2h/d的中介效应占总效应比例为4.01%,儿童运动与视屏知识满分的中介效应占比为11.40%(均P<0.05)。结论该综合干预项目可以增加儿童视屏时间达到指南标准的比例,其中家长限制儿童视屏时间不超过2h/d和儿童的运动和视屏知识满分发挥了部分中介作用。 展开更多
关键词 视屏时间 家长限制 儿童知识 干预 中介效应
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黑龙江省成年人身体活动和静态行为状况分析
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作者 闫世春 王亦南 +4 位作者 靳林 李阳春 崔晓明 周勇 周雪 《中国初级卫生保健》 2024年第3期34-36,41,共4页
目的:了解黑龙江省成年人身体活动和静态行为状况并进行分析,为改善居民不良生活习惯提供参考。方法:2018年6—12月,采用多阶段随机整群抽样法,选取黑龙江省10个县(市、区)作为国家级慢性病与营养监测点,对监测点18岁及以上居民进行身... 目的:了解黑龙江省成年人身体活动和静态行为状况并进行分析,为改善居民不良生活习惯提供参考。方法:2018年6—12月,采用多阶段随机整群抽样法,选取黑龙江省10个县(市、区)作为国家级慢性病与营养监测点,对监测点18岁及以上居民进行身体活动和静态行为问卷调查。结果:调查对象经常锻炼率为15.70%,从不锻炼率为77.70%,日平均总静态行为时间为(4.60±2.69) h,日平均看电视、使用电脑、玩电子游戏、使用手机的屏幕时间为(2.82±2.02) h,日平均睡眠时间为(7.14±1.63) h。结论:黑龙江省成年人经常锻炼率较低,身体活动不足普遍存在,业余静态行为时间较长。相关部门应关注居民身体锻炼情况,由体育指导员引领居民开展适合的体育活动;应通过提高人群的经常锻炼率和缩短屏幕时间防控慢性病;应加强健康宣传与促进,使居民意识到身体活动的益处,从而提高居民的健康水平。 展开更多
关键词 身体活动 静态行为 屏幕时间 分析
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串联网式过滤器拦截特性和过滤时间分析
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作者 刘贞姬 杨昊 +2 位作者 李俊峰 雷辰宇 龙洋娟 《农业工程学报》 EI CAS CSCD 北大核心 2024年第15期85-93,共9页
针对网式过滤器在实际灌溉水源条件下易堵塞、使用寿命短等问题,该研究将泵前和泵后网式过滤器串联组合,通过室内原型试验分析各级过滤器对泥沙和木屑的拦截规律。结果表明:过滤器拦截泥沙和木屑的分布情况与各级滤网孔径有关,当水源杂... 针对网式过滤器在实际灌溉水源条件下易堵塞、使用寿命短等问题,该研究将泵前和泵后网式过滤器串联组合,通过室内原型试验分析各级过滤器对泥沙和木屑的拦截规律。结果表明:过滤器拦截泥沙和木屑的分布情况与各级滤网孔径有关,当水源杂质以泥沙为主时,建议选取0.32和0.20 mm孔径滤网的泵前和泵后过滤器进行过滤,当有机物杂质含量较高时,采用0.25~0.32 mm滤网孔径的泵前过滤器有利于延长过滤时间。对水头损失随过滤时间的变化规律进行分析,明确了水源条件和滤网孔径对过滤时间的影响,极差和方差分析结果表明:不同进水流量条件下,初始水头损失和水头损失峰值分别集中在2.43~5.87和13.92~28.92 m,杂质含量对水头损失影响较小;进水流量越大,过滤器过滤时间越短。建立水头损失计算公式和过滤时间拟合经验公式,拟合与试验结果误差小于7%。各因素对过滤时间影响程度由大到小依次是杂质含量、滤网孔径、含沙量、进水流量。基于多层感知机(multilayer perceptron,MLP)神经网络模型对过滤时间进行预测,预测值与实测值误差基本在10%以内,均方误差和平均相对误差分别为0.32%、5.85%,该模型适用于对复杂水源条件下过滤时间的预测。研究结果可为灌溉工程中串联网式过滤器各级滤网参数的合理配置提供参考。 展开更多
关键词 灌溉 过滤器 滤网 过滤时间 拦截特性 杂质含量 MLP神经网络
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超高效液相色谱-四极杆-飞行时间高分辨质谱用于化妆品中15种前列腺素类似物的快速筛查和测定
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作者 陈安丽 张静 +1 位作者 黄子沣 严小红 《分析测试学报》 CAS CSCD 北大核心 2024年第7期1011-1017,共7页
建立了超高效液相色谱-四极杆-飞行时间高分辨质谱(UPLC-Q-TOF MS)快速筛查和测定化妆品中15种前列腺素类似物的方法。样品以饱和氯化钠作为分散剂(蜡质类样品以四氢呋喃分散),经乙腈提取,离心取上清液过滤后,采用Poroshell 120 EC-C_(... 建立了超高效液相色谱-四极杆-飞行时间高分辨质谱(UPLC-Q-TOF MS)快速筛查和测定化妆品中15种前列腺素类似物的方法。样品以饱和氯化钠作为分散剂(蜡质类样品以四氢呋喃分散),经乙腈提取,离心取上清液过滤后,采用Poroshell 120 EC-C_(18)柱(150 mm×3.0 mm,2.7μm)分离,以5 mmol/L甲酸铵(含0.1%甲酸)-乙腈为流动相梯度洗脱。在ESI正离子模式下,采用Targeted MS/MS模式采集15种前列腺素类似物的质谱信息,构建筛查数据库进行快速筛查,确证后的目标物通过外标法定量。结果表明,15种前列腺素类似物的线性关系良好,相关系数(r^(2))均大于0.99;检出限为0.3~17.6μg/g,定量下限为1.1~58.8μg/g。在低、中、高3个加标水平下,水剂、膏霜、乳类、粉类、凝胶5类化妆品基质的回收率为70.1%~134%,相对标准偏差不大于7.5%。该方法简单高效、准确度好,可用于化妆品中前列腺素类似物的定性确证和定量分析,为化妆品风险识别提供技术支撑。 展开更多
关键词 超高效液相色谱-四极杆-飞行时间高分辨质谱 快速筛查 化妆品 前列腺素类似物
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广州市越秀区青少年近视特点和危险因素分析
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作者 周焕宁 陈力 +1 位作者 温燕婷 朱紫杭 《广州医药》 2024年第5期541-547,共7页
目的探讨广州市越秀区青少年近视特点和危险因素,为降低青少年近视发病率提供参考依据。方法本项目采用分层随机整群抽样的研究方法,抽取分布于广州市越秀区2774名青少年作为研究对象,根据近视检查情况将其分为近视组(n=1657)与非近视组... 目的探讨广州市越秀区青少年近视特点和危险因素,为降低青少年近视发病率提供参考依据。方法本项目采用分层随机整群抽样的研究方法,抽取分布于广州市越秀区2774名青少年作为研究对象,根据近视检查情况将其分为近视组(n=1657)与非近视组(n=1117),通过问卷调查的方式,分析青少年近视整体现况、流行病学特征以及影响青少年近视发生、发展的相关行为和因素。结果2774名青少年中,1657名近视,检出率为59.73%;其中女生为872名,多于男生的785名;幼儿园、小学生、初中生、高中生近视人数分别为20名、446名、484名、707名,呈升高趋势。学段、校内用眼环境、校外用眼环境、读写姿势、电子屏幕使用情况、近距离用眼情况、户外活动及睡眠情况、近视检查及矫治情况是广州市越秀区青少年近视的影响因素(P<0.05)。广州市越秀区青少年近视程度均与学段、校外用眼环境、电子屏幕使用情况、户外活动及睡眠情况、近距离用眼情况呈正相关(P<0.05),与校内用眼环境、读写姿势、近视检查及矫治情况呈负相关(P<0.05)。对不同预后组间存在统计学差异的因素进行Logistic多因素分析后得到,学段、校内用眼环境、校外用眼环境、读写姿势、电子屏幕使用情况、近距离用眼情况、户外活动及睡眠情况、近视检查及矫治情况是广州市越秀区青少年近视的相关影响因素(P<0.05)。结论广州市越秀区青少年近视发生人群呈现高龄化,学段、校内用眼环境、校外用眼环境、读写姿势、电子屏幕使用情况、近距离用眼情况、户外活动及睡眠情况、近视检查及矫治情况是青少年近视的相关影响因素,建议加强组织学生到户外进行多种课间户外体育活动,同时鼓励家长在校外从自身做起,树立爱眼护眼好榜样,与学校共同保护孩子的视力。 展开更多
关键词 近视 校内用眼情况 校外用眼情况 屏幕使用时间
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基于频域阈值处理广义互相关和空间筛选的多源局部放电定位方法 被引量:3
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作者 关宇 董明 +3 位作者 席英杰 李易 张崇兴 任明 《电网技术》 EI CSCD 北大核心 2024年第4期1721-1730,I0089,I0091-I0093,共14页
该文针对电力设备的多源局部放电定位问题,提出了基于频域阈值处理广义互相关(frequency domain threshold processing generalized cross-correlation,FDTP-GCC)和空间筛选的多源局部放电定位方法。为实现多源局部放电超声信号的同源... 该文针对电力设备的多源局部放电定位问题,提出了基于频域阈值处理广义互相关(frequency domain threshold processing generalized cross-correlation,FDTP-GCC)和空间筛选的多源局部放电定位方法。为实现多源局部放电超声信号的同源时间差提取问题,该文提出了FDTP-GCC算法,该算法直接应用于超声传感设备采集的原始信号,在频域内通过设置幅度谱阈值排除干扰频段,幅度谱归一化突出多源信号时间差的冲激函数特征,直接得到对应同源信号的时间差。通过仿真证明了FDTP-GCC算法进行时间差估计的高准确性、高稳定性、高抗噪能力。为解决FDTP-GCC算法带来的同源时间差分离的问题,该文提出了基于空间筛选的多源局部放电定位方法,并分析了采用基于解析解的算法和智能算法进行空间筛选的定位性能。最后采用双局部放电源进行了定位试验,试验结果表明该文方法提取的时间差误差均在1μs以内,两个局部放电源的定位误差为20.53cm和4.93cm。 展开更多
关键词 局部放电 超声定位 到达时间差 频域阈值处理广义互相关 空间筛选
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