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21.
CORDIC算法在B超数字扫描变换器中的应用 总被引:1,自引:0,他引:1
数字扫描变换器在B型超声诊断仪的应用,能使现代实时B型超声诊断仪实现一些新的诸如图像冻结、多帧贮存、数据测量计算和TV显示等功能。在设计B型超声诊断仪中数字扫描变化器的过程中,直角坐标到极坐标变换是一个关键的技术,本研究论述了应用在数字扫描变化器中的一种新的算法——CORDIC算法,对该算法的原理进行了简介,将CORDIC算法应用到直角——极坐标变换中,并进行了算法修正和公式计算。根据其具体的应用对该算法进行了优化,并给出了算法的硬件实现结构。最后,对算法进行了软件仿真,并给出了结果分析。 相似文献
22.
We determined the microviscosity of synaptosomal plasma membrane vesicles (SPMV) isolated from bovine cerebral cortex and
liposomes of total lipids (SPMTL) and phospholipids (SPMPL) extracted from SPMV. Changes in the microviscosity induced by
the range and rate of lateral diffusion were measured by the intramolecular excimerization of 1,3-di(1-pyrenyl)-propane (Py-3-Py).
The microviscosity values of the direct probe environment in SPMV, SPMTL and SPMPL were 38.17, 31.11 and 27.64 cP, respectively,
at 37°C and the activation energies (Ea) of the excimer formation of Py-3-Py in SPMV, SPMTL and SPMPL were 8.236, 7.448 amd 7.025 kcal/mol, respectively. Probe location
was measured by polarity and polarizability parameters of the probe Py-3-Py and probe analogues, pyrene, 1-pyrenenonanol and
1-pyrenemethyl-3β-hydroxy-22,23-bisnor-5-cholenate (PMC), incorporated into membranes or solubilized in reference solvents.
There existed a good linear relationship between the first absorption peak of the1La band and the polarizability parameter (n
2−1)/(2n
2+1). The calculated refractive index values for SPMV, SPMTL and SPMPL were close to 1.50, which is higher than that of liquid
paraffin (n=1.475). The probe location was also determined by using a polarity parameter (f−1/2f1). Here f=(ε−1)/(2ε+1) is the dielectric constant function and f'=(n
2−1)/(2n
2+1) is the refractive index function. A correlation existed between the monomer fluorescence intensity ratio and the solvent
polarity parameter. The probes incorporated in SPMV, SPMTL, and SPMPL report a polarity value close to that of 1-hexanol (ε=13.29).
In conclusion, Py-3-Py is located completely inside the membrane, not in the very hydrophobic core, but displaced toward the
polar head groups of phospholipid molecules, e.g., central methylene region of aliphatic chains of phospholipid molecules. 相似文献
23.
在微型诊疗装置的应用中,微型装置的体内空间定位非常重要,而定位数据的采集是其中的关键环节.根据体内微型装置磁定位实验研究系统数据采集的特点,设计出一种基于单片机和串口通信的计算机接口用于定位数据的收集、传输等.实验表明,该接口电路能满足实时采集数据的需要,数据传输可靠,在计算机中可以进行现场采集数据的实时保存及其他后处理,能满足实验系统的要求. 相似文献
24.
Blurring the distinctions between on and off the job injuries: similarities and differences in circumstances.
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OBJECTIVES: To compare the causes of non-fatal work and non-work injuries and the places or environments where they occur. It has been suggested that many injuries may have similar etiologies on and off the job and thus involve some common prevention strategies. However lack of comparable data on work relatedness has prevented testing this proposition. METHODS: The National Health Interview Survey (NHIS) now collects information on the cause, location, and work relatedness of all medically attended injuries. National US estimates of non-fatal work and non-work injuries were compared by cause and place/location for working age adults (18-64 years). RESULTS: Overall 28.6% of injuries to working age adults were work related (37.5% among employed people). The causes and locations of many work and non-work injuries were similar. Falls, overexertion, and struck/caught by were leading causes for work and non-work injuries. Motor vehicle injuries were less likely to be work related (3.4% at work v 19.5% non-work) and overexertion injuries more likely to be work related (27.1% v 13.8%). Assaults were less than 1% of work injuries and 1.8% of non-work injuries. Both work and non-work injuries occurred in every location examined-including the home where 3.5% of injuries were work related. CONCLUSIONS: Work and non-work injuries share many similarities suggesting opportunities to broaden injury prevention programs commonly restricted to one setting or the other. Comprehensive efforts to prevent both non-work and work injuries may result in considerable cost savings not only to society but also directly to employers, who incur much of the associated costs. 相似文献
25.
球花石斛茎中香豆素类成分的定位与相对定量 总被引:5,自引:0,他引:5
目的探讨不同生长年限、不同部位球花石斛 (Dendrobium thyrsiflorum Rchb. f.)茎中香豆素类(coumarins)成分的分布与相对含量变化,为合理评价及利用药用石斛提供科学依据。方法利用激光共聚焦显微技术(laser scanning confocal microscopy, LSCM)观察二月份采收的球花石斛1-3龄茎的基部、中部和顶部的香豆素类成分。所记录数据经正态性、方差齐性检验后进行方差分析(ANOVA),并使用Tukey′s检验作多重比较。结果 香豆素类成分主要分布在球花石斛茎的维管束部位并以维管束外侧纤维的壁较多。统计分析显示香豆素类成分的含量在不同年龄茎的各个部位之间差异极显著或显著,显著值分别为:基部P=0.004(<0.01);中部P=0.009(<0.01);顶部P=0.036(<0.05)。结论若以利用香豆素类成分为目的,建议二月采收时,宜选择2龄茎。 相似文献
26.
目的分析海南地区Dravet综合征患儿的遗传特征。方法收集2015—2017年期间海南省18例Dravet综合征患儿及家系成员的外周血,采用PCR扩增及Sanger测序法进行SCN1A基因检测,运用连锁分析应用软件GenomeStudio进行致病基因定位分型与连锁分析;对Sanger测序法未发现SCN1A基因突变的患儿,采用多重连接依赖的探针扩增(MLPA)方法分析SCN1A基因片段缺失或重复,并筛查父母SCN1A基因,分析其突变来源。结果 18例Dravet综合征患儿及父母基因定位扫描结果完全符合亲子间的孟德尔遗传关系。SCN1A基因突变患儿可定位到5号、9号、22号染色体3个候选突变区域。其中5号染色体区域位于SNPRs 4957954至Rs 728937,在Rs 1459085处可获取到最大LOD值2. 13;9号染色体区域位于SNPRs 720974至Rs 1220087,在Rs 71332677处可获取到最大LOD值1. 92;22号染色体区域位于SNPRs 756658至Rs 713751,在Rs 374225处可获取到最大LOD值1. 91。18例患儿中,12例SCN1A基因突变,其中6例CDS区域的第5383位碱基呈现杂合变异(G→A),4例13号外显子和CDS区域的第2292位碱基纯合变异(T→C),2例SCN1A基因非编码区域碱基纯合变异(A→T)。结论海南Dravet综合征患儿的基因定位完全符合孟德尔遗传关系,推测Rs4957954至Rs728937、Rs720974至Rs1220087、及Rs756658至Rs713751区域是Dravet综合征的可能致病性区域。 相似文献
27.
目的 分析在冠状动脉粥样硬化性心脏病(以下简称冠心病)诊断及病变血管定位中经胸实时三维超声可视化模型的应用价值.方法 选取2017年10月—2019年5月重庆三峡中心医院疑似冠心病并接受经胸实时三维超声可视化模型诊断者128例进行回顾性分析,均实施冠状动脉造影检查,并将其检查结果作为"金标准",明确经胸实时三维超声可视... 相似文献
28.
29.
Naofumi Ikeda Toshihide Hayashi Shikou Gen Nobuhiko Joki Kazuhiko Aramaki 《Renal failure》2022,44(1):1098
PurposeTo determine the location of coronary atherosclerosis distribution observed in patients with chronic kidney disease (CKD).MethodsA cross-sectional study was conducted using the database of cardiovascular medicine data from Saitama Sekishinkai Hospital to clarify the association between renal function and angiographic characteristics of coronary atherosclerosis. In total, 3268 patients who underwent percutaneous coronary intervention were included. Propensity score matching revised the total to 1772. The association of renal function with the location and/or distribution of coronary atherosclerosis lesions was then examined.ResultsOverall, coronary lesion was observed in the left anterior descending coronary artery (LAD) in 56% patients, whereas 28% and 22% were in the right coronary artery (RCA) and left circumflex coronary artery (LCX), respectively. LAD was most affected and observed in 57% patients with stage 1 CKD. RCA was second-most affected, at 26% CKD stage 1, but it increased to 31%, 38%, and 59% in CKD 3, 4, and 5, respectively. In CKD 5 patients, the RCA was the most affected artery (59%), with 41% LAD lesions. Logistic regression analysis after propensity score matching showed that the odds ratios for an RCA lesion was 3.658 in CKD 5 (p = .025) compared with CKD 1 after adjusting for traditional risk factors.ConclusionThe prevalence of RCA lesions, but not LAD or LCX lesions, increased with increasing CKD stage. The pathophysiology of coronary atherosclerosis may differ by lesion location. Deterioration of renal function may affect progression of atherosclerosis more in the RCA than in the LAD or LCX. 相似文献
30.
分析《本草经》药物产地分布的区域特征后指出 :以出产药物数量计 ,汉代十三部政区中之益州 ,郡国中之泰山都是当时大宗药物产地 ;从药物产地分布来看 ,药物出产分别以东都雒阳、西京长安为中心 ,向外辐射 ,而东部产药多于西部 ;推测位于雒阳与长安中心点的弘农郡 ,可能是东汉时期重要的药材贸易场所 :《本草经》关于药物产地的记载 ,反映了此书对药物道地性的重视 ,同时也在一定程度上揭示了秦汉以来药物道地产区的变化。 相似文献