新歼平显画面计算机仿真练习效果的模拟器验证研究

考察新歼平显画面计算机仿真练习对于提高飞行员平显画面认知效果的有效性和可靠性。方法飞行员10名,按模拟器的前测成绩分为对照组和试验组。试验组应用平显计算机仿真练习,对照组无练习。练习六天后对10名飞行员进行模拟器的后测。比较施加不同处理的两组被试其在模拟器上考核的前后成绩和反应时间是否有差别。结果试验组与对照组在模拟器考核的前后成绩上有差别（P〈0.05）,两组在试验前后综合感知模拟器平显画面的反应时间差异不显著。结论使用平显画面计算机仿真练习反复进行练习,能够在一定程度上提高飞行员对飞行训练模拟器平显画面的认知成绩。     

新型歼击机平显武器瞄准符号显示格式的实验研究

比较飞行员对格斗模式下平显（Head Up Display,HUD）导弹一航炮两种瞄准符号显示格式的认知操作效果和使用评价意见,在此基础上提出新型歼击机HUD导弹一航炮显示的建议方案。实验采用2×2重复测量设计,以151名空军现役歼击机飞行员为实验对象,完成HUD导弹一航炮不同显示格式画面的测试,并在实验结束后对每种显示格式做出“优、良、中、差”的等级评定。根据工效学实验的结果数据和飞行员的使用性评价意见,提出新型歼击机HUD武器瞄准符号显示格式的优化方案。     

新型歼击机平显地空数传指令显示方案的工效学实验研究

比较飞行员对平显(Head Up D isp lay,HUD)地空数传指令各种显示方案的认知操作效果和使用评价意见,在此基础上提出新型歼击机HUD地空数传指令显示的建议方案。实验采用2×2×2重复测量设计,以151名空军现役歼击机飞行员为实验对象,完成HUD地空数传指令不同显示方案共8幅画面的测试,并在实验结束后对每种显示方案做出“优、良、中、差”的等级评定。根据工效学实验的结果数据和飞行员的使用性评价意见,提出新型歼击机HUD数传指令显示的优化方案。     

基于表面肌电信号对比分析的膝下假肢爬梯补偿机制研究

表面肌电信号是测试肌力大小的重要指标之一。本文通过对6名健体者（健康人组）和6名膝下假肢者（残疾人组）爬梯活动中左右竖脊肌和左右股直肌的表面肌电的时域和频域分析,对比两组被试在爬梯过程中的这四块主要活动肌群肌力的差异。结果,无论是中值频率（Mr）还是积分肌电值（iEMG）,残疾人被试在假肢一侧的股直肌指标值都要显著小于其健体一侧（P〈0．05,n=87）,也小于健康被试的股直肌。残疾被试的竖脊肌显著大于健康被试（P〈O．001,n=87）。研究表明,爬梯过程中,残疾人假肢一侧的股直肌持久力和爆发力均弱于其他身体部位,腰部及健体一侧提供能力补偿。     

模拟应急条件下的反应时研究

本研究用模拟任务负荷和紧张情绪负荷法分别测定了１０８名健康男性（其中５６名飞行员）和９名航空试验用锻炼员对应急信号做出反应并完成应急操纵动作所用的时间（ＲＴ＋ＭＴ），在平静无负荷状态下测定了４５名健康男性对声、光信号的反应时间ＰＲＴ。结果表明，飞行员组的（ＲＴ＋ＭＴ）在训练前后分别平均为１．７２５５和１．２７３５，对声、光信号的ＰＲＴ平均值分别为０．２７２５（声）、０．３１２ｓ（红）、０．３０３ｓ（绿）、０．３０２ｓ（蓝）；飞行员组与普通被试组无显著差异；紧张因素的影响未达显著程度；训练因素能显著提高反应能力。     

丙泊酚联合芬太尼用于妇科手术硬膜外麻醉的临床观察

目的探讨丙泊酚联合芬太尼用于妇科手术硬膜外麻醉的临床效果。方法ASAⅠ-Ⅱ级择期妇科手术的患者80例,随机分为丙泊酚联合芬太尼组（实验组）和芬太尼异氟醚组（对照组）,每组40例。观察血流动力学变化、麻醉苏醒及不良反应等情况。结果两组患者术中心率、呼吸、血氧饱和度和平均动脉压同术前相比差异无显著性,用药后两组比较差异有统计学方法（P〈0．05）;两组患者术后自然清醒、呼唤睁眼时间、自主呼吸恢复时间差异均有统计学意义（P〈0．05）。结论丙泊酚联合芬太尼用于妇科手术硬膜外麻醉安全、效果好。     

起飞阶段不同能见度对飞行员的眼动行为影响分析

目的为了研究飞行员在低能见度下的眼动行为模式与工作负荷。方法使用Smart Eye眼动仪跟踪被试的眼睛,使用Prepare 3D模拟飞行软件构建仿真实验平台,开展不同能见度下的起飞模拟飞行实验。结果低能见度下起飞使用平视显示器飞行员主观工作负荷有所增加,但并不显著;低能见度下,飞行员眼动行为有差异,但并不显著。结论起飞阶段,使用平视显示仪,低能见度对被试人员的工作负荷、信息感知、搜索、加工过程并无显著影响。     

产科门诊标准化健康教育程序对初产妇分娩恐惧的影响

目的：探究产科门诊标准化健康教育程序在初产妇中的应用，观察其对初产妇分娩恐惧的影响。方法：选择2021年1月-2022年1月来医院门诊进行产检的孕妇92例作为本次研究对象，根据随机数字表法分为对照组（n=46）采取常规健康教育；观察组（n=46）采取产科门诊标准化健康教育程序，比较两组产妇的分娩恐惧、负面情绪及对门诊护理的满意度。结果：干预前，两组初产妇对分娩的恐惧比较差异无统计学意义（P>0.05）；对初产妇进行门诊标准化健康教育程序干预后，观察组孕妇对分娩的恐惧低于对照组（P<0.05）。干预前，两组患者就诊满意度比较差异无统计学意义（P>0.05）；观察组孕妇就诊满意度高于对照组（P<0.05）；干预前，两组患者焦虑、抑郁情绪比较差异无统计学意义（P>0.05）；干预后，两组患者负面情绪均减少且观察组少于对照组（P<0.05）。结论：给予初产妇在产科门诊标准化健康教育程序干预能够帮助患者由于分娩产生的恐惧心理，减少患者由于担忧产生的负面情绪，增加患者在就诊时的满意度。本研究经本院医学伦理委员会审批。     

高血压左心功能常规指标与声学定量技术比较

为了将反映高血压患者心功能的常规指标与声学定量技术（Acoustic Quantification,AQ）指标进行比较分析,评价高血压左心功能变化,将实验对象分为对照组30例和高血压病组45例,将高血压组分成非肥厚组和肥厚组;对各组进行了常规心功能指标及AQ检测。各组间DBP、LVM、LVMI、IVS、IVPW、LA有显著性差异（P〈0.05）。与对照组相比,非肥厚组与肥厚组的VE/VA及RF/AF降低,AFF及LVESV增加（P〈0.05）。与对照组相比,肥厚组RFF降低,PAFR、LVEDV及OAFV增加（P〈0.05）。常规心功能指标中EF同AQ指标中EF进行非配对T检验,显示前者低于后者（P〈0.05）。实验结果表明,AQ技术作为一种新的能评价舒张功能障碍的新方法,可视为常规超声心动图指标的补充,结合此两种方法可有效提高临床诊断左心室舒张功能异常。     

多排螺旋CT低剂量扫描在成人颅脑检查中的应用价值

目的：探讨多排螺旋CT低剂量扫描在成人颅脑检查中的应用效果与价值。方法：选取我院开展常规体检的健康成人500例,采用数字随机方法将样本分为5组,每组各100例,A组样本给予常规剂量扫描,其他4组分别采用80、100、160、200m As的低剂量扫描。依据每组样本的图像质量开展评分与辐射剂量比较。结果 ：通过具体评分后,C组、D组、E组的图像质量优良率与A组比较未见明显差异,不存在统计学意义（P〉0.05）。B组扫描图像质量优良率为68%,显著低于其他4组,具有统计学意义（P〈0.05）,临床数据显示B组、C组、D组、E组间的CT剂量指数与平均剂量长度乘积比较均无统计学意义（P〉0.05）,而A组样本的CT剂量指数为46.71m Gy,平均剂量长度乘积为560.01m Gy·cm,均显著高于其他4组,具有统计学意义（P〈0.05）。结论：针对成人开展颅脑检查时选用管电流为100m As的低剂量多排螺旋CT扫描,能够确保扫描图像的质量,也降低受检者的辐射剂量,减少不良事件的发生率。     

基于脑电非线性动力学特征探究TEAS内关穴对焦虑的影响

基于脑电非线性动力学特征,探究经皮穴位电刺激(TEAS)内关穴对焦虑的影响及其机制.实验选取l2位焦虑受试者随机分为TEAS内关穴干预组(穴位组)和TEAS非穴位干预组(非穴位组),分别采集电刺激前后各组受试者脑电数据,提取脑电信号的特征近似熵(ApEn)与关联维数(D2),分析大脑复杂度的变化,同时比较电刺激前后焦虑...     

Coincidence Doppler broadening study on hydrocarbons with pi and sigma valence electrons: positronium correction

The coincidence Doppler broadening (CDB) technique was applied to study the electron momentum distribution in anthracene, diphenyl, naphthalene, and polystyrene. A method for separation of the positron and positronium (Ps) components from the Doppler-broadened annihilation line (DBAL) was developed further to be applicable to hydrocarbons with different π and σ valence electron distributions. This method allows extraction of the electron momentum distribution (EMD) from DBAL for samples when Ps formation occurs. The annihilation on π valence electrons was detected as broadening of the EMD compared to that obtained for a polymer sample only with σ valence electrons. The broadening appeared as a significant change in the shape of the CDB ratio of the corresponding positronium-corrected curves: a slight enhancement above the unity line in the low-momentum region and a drop in the momentum region, 10–20×10⁻³m_oc.     

Potential for improving the Rubidium Frequency Standard with anovel optical pumping scheme using diode lasers

Frequency stability of a Rubidium Frequency Standard (RFS) is directly related to the signal-to-noise ratio (S/N) of the microwave-induced (6834 MHz) optical signal which is proportional to the fractional atomic population difference between the two M_F=0 ground state sublevels of ⁸⁷Rb. In the present RFSs this fractional population difference is small (<1%). S/N can be substantially improved by concentrating all of the atoms in one of the two M_F=0 sublevels. Potentially, this could lead to a significant improvement in the short-term performance of RFSs. We have developed a novel scheme for concentrating a large fraction of the Rb atoms in one of the two M_F=0 ground state sublevels. We optically pump the Rb vapor with circularly polarized light from a AlGaAs diode laser tuned to the D₁ transition (794.7 nm). Nearly all of the atoms are concentrated in one of the two high angular momentum states (M_F=2 or -2 sublevels depending on the handedness of the circular polarization). The pumping laser is switched off and two radiofrequency (RF) π-pulses are applied sequentially. The first π-pulse transfers the atoms from the 2,2(F,M_F) sublevel to the 2,1 sublevel and the second π-pulse transfers the atoms from the 2,1 sublevel to the 2,0 sublevel. The resulting population distribution is diagnosed using a second AlGaAs diode laser (weak probe) in conjunction with a microwave field tuned to the 0-0 transition (6834 MHz). We obtain a fractional population difference of 0.7-0.9 between the two M_F=0 sublevels. This should result in an improvement in the S/N by a factor of 70-90 over the lamp pumped RFSs. This could potentially be of considerable importance towards the development of future RFSs. Various relaxations and field inhomogeneities limit the transfer efficiency from being 100%. The details of the experimental technique and possible applications are discussed     

影响血清蛋白检测结果的放置时间分析及对策

目的评估血清标本在运行自动生化分析仪器中放置时间对血清总蛋白(TP)、白蛋白(ALB)检测结果的影响。方法按放置时间2、4、6、8h,分4组,每组20份标本;对照管只测TP和ALB。结果血清标本在运行仪器中放置2、4h,TP和ALB与对照管比较无显著性变化;放置6、8h后,TP和ALB与对照管比较显著升高。结论标本在运行的分析仪器中的放置时间,属于分析前的影响因素必须引起观注,并提出相应的对策。     

Performance optimisation of the micro pixel chamber

A thorough performance analysis of large-area μ-PIC detectors has been made. Through systematic simulations and comparison with test results of the two detector versions, μ-PIC1 and μ-PIC3, we have identified that low primary electron collection was responsible for the degradation of measured gas gain of the μ-PIC3 device. The test of a new detector, μ-PIC5, fabricated with a narrower inter-cathode gap and anodes raised above the insulator surface, shows a threefold increase in gas gain reaching 10⁴ in argon 80%–ethane 20% gas mixture, which agrees with simulations. The new detector demonstrates a stable long-term operation at high gains, above 6000 measured during more than 70 h with an X-ray source, with a moderate 6% gain increase due to dielectric polarisation.     

Artificial neural network modelling of uncertainty in gamma-ray spectrometry

An artificial neural network (ANN) model for the prediction of measuring uncertainties in gamma-ray spectrometry was developed and optimized. A three-layer feed-forward ANN with back-propagation learning algorithm was used to model uncertainties of measurement of activity levels of eight radionuclides (²²⁶Ra, ²³⁸U, ²³⁵U, ⁴⁰K, ²³²Th, ¹³⁴Cs, ¹³⁷Cs and ⁷Be) in soil samples as a function of measurement time. It was shown that the neural network provides useful data even from small experimental databases. The performance of the optimized neural network was found to be very good, with correlation coefficients (R²) between measured and predicted uncertainties ranging from 0.9050 to 0.9915. The correlation coefficients did not significantly deteriorate when the network was tested on samples with greatly different uranium-to-thorium (²³⁸U/²³²Th) ratios. The differences between measured and predicted uncertainties were not influenced by the absolute values of uncertainties of measured radionuclide activities. Once the ANN is trained, it could be employed in analyzing soil samples regardless of the ²³⁸U/²³²Th ratio. It was concluded that a considerable saving in time could be obtained using the trained neural network model for predicting the measurement times needed to attain the desired statistical accuracy.     

Position sensitivity of the TIGRESS 32-fold segmented HPGe clover detector

Sensitivity to the locations of γ-ray interactions within a 32-fold segmented clover-type HPGe detector has been investigated through 90 Compton scattering of -rays from a collimated source. A mean position sensitivity of 0.44 mm at an energy of 373 keV is deduced by comparing the average pulse shapes for net charge collecting signals, as well as transient induced signals in neighbouring contacts, from 1007 pairs of three-dimensionally localized interaction points. The reconstruction of individual event locations based on a χ² comparison with the measured set of basis waveforms is presented.     

Monitoring and blunting styles in fluid restriction consultation

Excessive fluid overload is common in hemodialysis patients. Understanding fluid intake behavior in relation to used cognitive coping style would serve the fluid restriction consultation. The aim of this study was to explore whether hemodialysis patients' fluid intake behavior differs as a function of used coping style. Secondary analysis of data from 51 hemodialysis patients regarding cognitive coping style (assessed by the Threatening Medical Situations Inventory) and fluid intake behavior were used. The participants' mean age was 62.9 years (range 27-84), they had received dialysis treatment for 3.9 years on average (range 0-22), 63% were male and they had gained 3.6% (±1.3) of their dry body weight during the interdialytic period. There was a significant difference in fluid intake behavior between coping groups (F = 3.899, d.f. 2, P = 0.027). The difference (P = 0.028) was isolated between patients with cognitive blunting style and patients with neutral coping style. Identification of hemodialysis patients using cognitive avoidance strategies can be advantageous in renal care. Fluid advice provided may have to be adjusted to the used coping style, especially for patients with a blunting coping style. However, the findings need to be confirmed, and the effect of individualized counseling needs to be evaluated in forthcoming studies.     

Karate injuries in children and adolescents

OBJECTIVES: To identify risk factors for injury and to establish safety guidelines for children in Uechi-Ryu karate. DESIGN: A 1-year retrospective survey of injuries. SETTING: A private karate school (Uechi-Ryu style) in Plymouth, MA. PATIENTS: A total of 68 athletes (age 6-16 years; mean age 10 years) who participated in karate during the 1995-1996 season. INTERVENTIONS: None. MAIN OUTCOME MEASURES: The presence or absence of injury, with grading of injuries as major, moderate or minor. The types of injuries and body region involved were also analyzed. RESULTS: Twenty eight percent of athletes sustained at least one injury. All injuries were minor, with no time off from training required. The injuries consisted primarily of bruises (11 of 19). Other injuries included mild sprains or strains (5 of 19) and having their 'wind knocked out' (3 of 19). Most injuries were localized to the extremities. Logistic regression analysis identified risk factors for injury. Risk of injury increased with number of years of training (odds ratio 2.95; 95% confidence interval 1.81-4.82; P<0.0001), number of hours per week (odds ratio 2.12; CI 1.15-4.21; P = 0.016) and rank, specifically brown belt versus lower belts (odds ratio 6.56; CI 2.02-21.26; P = 0.006). CONCLUSIONS: Karate is a relatively safe sport for children and adolescents when properly taught. Risk of injury increases with experience; therefore, greater supervision is required of higher ranks. Injury increases with weekly training; however, 3 h a week or less appears to be associated with a low risk of significant injury in this age group.     

GRAPES-3—A high-density air shower array for studies on the structure in the cosmic-ray energy spectrum near the knee

The change in the spectral index from about -2.7 to -3.1 at 3×10¹⁵ eV in the all-particle energy spectrum of primary cosmic rays is very significant for learning about the nature of cosmic sources of ultra-high energy particles and their acceleration and propagation in the galactic disk. Any observation of a fine structure in the spectrum would be important for improving our understanding of these physical processes. The GRAPES-3 air shower array has been designed to achieve higher precision in determination of various shower parameters to enable observation of any fine structure in the energy spectrum, if it exists. The details of the shower detectors, shower trigger and the data acquisition system are presented here along with estimates of trigger efficiencies from Monte Carlo simulations for primary photons (γ-rays) and several nuclei.