Preparation of large rylenes often needs the use of solubilizing groups along the rylene backbone,which results in the distortion of the skeleton and thus broadening of the absorption spectrum.In this work,we successf...Preparation of large rylenes often needs the use of solubilizing groups along the rylene backbone,which results in the distortion of the skeleton and thus broadening of the absorption spectrum.In this work,we successfully synthesized 2,5,8,16,19,22-hexakis[2,6-bis(tri-fluoromethyl)phenyl]hexarylene(H)by using an oxidative fusion reaction of perylene trimer in 5%yield.The product is soluble in common organic solvents and could be purified with column chromatography.Single-crystal X-ray diffraction analysis revealed that the hexarylene core is not disturbed by the substituents very much and is almost planar.The longest absorption of H exhibits a sharp peak at 831 nm and an on-set at 875 nm in toluene with a small full-width-at-half-maximum(FWHM)of 660 cm^(-1).The molar extinction coefficient is as large as 131,000 M^(-1)cm^(-1).The substituents could not perturb the electronic properties of the hexarylene because aryl groups are perpendicular to the hexarylene core and the carbon atoms at 2,5,16,19-positions have negligible coeffi-cients on its HOMO and LUMO,estimated by theoretical calculations.As a result,the hexarylene having less absorption at the visible light region was stable enough in solution under the LED room light for more than 1 week.This strategy gives a useful guideline to establish the near-infrared materials that exhibit stability under ambient conditions.展开更多
目的:分析基于高清小视野弥散加权成像(Field-of-View Optimized and Constrained Undistorted Single Shot Difusion Weighted Imaging,Focus-DWI)技术在乳腺癌术前磁共振扫描中的应用价值。方法:选取80例乳腺癌患者,均为某院2022年1月...目的:分析基于高清小视野弥散加权成像(Field-of-View Optimized and Constrained Undistorted Single Shot Difusion Weighted Imaging,Focus-DWI)技术在乳腺癌术前磁共振扫描中的应用价值。方法:选取80例乳腺癌患者,均为某院2022年1月~2024年4月所收治,全部患者均经过手术病理检查证实,术前接受乳腺常规DWI及Focus-DWI序列MRI检查;安排两名具有丰富临床经验的医师负责阅片,通过双盲法来主观评分常规DWI、Focus-DWI图像的整体质量、清晰度、伪影以及变形情况,并对正常乳腺腺体及乳腺癌的腺体表观弥散系数值进行测量,比较常规DWI及Focus-DWI序列的定量参数、主观评分。结果:相比于常规DWI序列成像,Focus-DWI序列成像的清晰度、整体图像质量评分均明显更高(P<0.05),而变形程度、伪影评分均明显更低(P<0.05)。与常规DWI序列成像相比较,Focus-DWI序列成像的乳腺癌表观弥散系数值明显更低(P<0.05)。结论:在乳腺癌术前磁共振扫描中,应用Focus-DWI技术能让整体图像质量显著提高,能让图像的模糊度、伪影、形变明显减少,和常规DWI序列相比较,Focus-DWI技术的病变显示效果、清晰度更加理性,更有利于诊断及观察乳腺癌。展开更多
针对经典的最小方差无畸变响应波束形成器应用在FDA-BFF(Frequency Diverse Array Based On Fre-quency Filter,FDA-BFF)及FDA-MIMO(Frequency Diverse Array Multiple-Input Multiple-Output,FDA-MIMO)接收机结构时,当阵元数较大或干...针对经典的最小方差无畸变响应波束形成器应用在FDA-BFF(Frequency Diverse Array Based On Fre-quency Filter,FDA-BFF)及FDA-MIMO(Frequency Diverse Array Multiple-Input Multiple-Output,FDA-MIMO)接收机结构时,当阵元数较大或干扰与目标角度维接近时波束主瓣会产生峰值畸变或偏移,波束形成器输出性能下降,无法有效确定目标位置的问题,提出了基于双边小方差无畸变响应的子阵频控阵波束形成算法。该算法将一维均匀线性阵列划分为两个采用不同非线性频偏的中心对称子阵结构,在目标位置形成点状波束,对传统频偏固定的频控阵方向图中的距离-角度实现解耦。之后,通过双边小方差无畸变响应算法中求解克罗内克积的方式降低了算法计算量。仿真验证表明,阵元数较大时该算法在目标位置处形成点状波束的同时,可以有效抑制角度维不可分的干扰。展开更多
基金supported by Grants-in-Aid for Scientific Research(Nos.JP20H02816(HH),JP20H00379(HY),JP20H05833(HY),JP20H02711(NA),JP22H19067(NA),JP22K05225(KM),JP20K15261(KM))。
文摘Preparation of large rylenes often needs the use of solubilizing groups along the rylene backbone,which results in the distortion of the skeleton and thus broadening of the absorption spectrum.In this work,we successfully synthesized 2,5,8,16,19,22-hexakis[2,6-bis(tri-fluoromethyl)phenyl]hexarylene(H)by using an oxidative fusion reaction of perylene trimer in 5%yield.The product is soluble in common organic solvents and could be purified with column chromatography.Single-crystal X-ray diffraction analysis revealed that the hexarylene core is not disturbed by the substituents very much and is almost planar.The longest absorption of H exhibits a sharp peak at 831 nm and an on-set at 875 nm in toluene with a small full-width-at-half-maximum(FWHM)of 660 cm^(-1).The molar extinction coefficient is as large as 131,000 M^(-1)cm^(-1).The substituents could not perturb the electronic properties of the hexarylene because aryl groups are perpendicular to the hexarylene core and the carbon atoms at 2,5,16,19-positions have negligible coeffi-cients on its HOMO and LUMO,estimated by theoretical calculations.As a result,the hexarylene having less absorption at the visible light region was stable enough in solution under the LED room light for more than 1 week.This strategy gives a useful guideline to establish the near-infrared materials that exhibit stability under ambient conditions.
文摘目的:分析基于高清小视野弥散加权成像(Field-of-View Optimized and Constrained Undistorted Single Shot Difusion Weighted Imaging,Focus-DWI)技术在乳腺癌术前磁共振扫描中的应用价值。方法:选取80例乳腺癌患者,均为某院2022年1月~2024年4月所收治,全部患者均经过手术病理检查证实,术前接受乳腺常规DWI及Focus-DWI序列MRI检查;安排两名具有丰富临床经验的医师负责阅片,通过双盲法来主观评分常规DWI、Focus-DWI图像的整体质量、清晰度、伪影以及变形情况,并对正常乳腺腺体及乳腺癌的腺体表观弥散系数值进行测量,比较常规DWI及Focus-DWI序列的定量参数、主观评分。结果:相比于常规DWI序列成像,Focus-DWI序列成像的清晰度、整体图像质量评分均明显更高(P<0.05),而变形程度、伪影评分均明显更低(P<0.05)。与常规DWI序列成像相比较,Focus-DWI序列成像的乳腺癌表观弥散系数值明显更低(P<0.05)。结论:在乳腺癌术前磁共振扫描中,应用Focus-DWI技术能让整体图像质量显著提高,能让图像的模糊度、伪影、形变明显减少,和常规DWI序列相比较,Focus-DWI技术的病变显示效果、清晰度更加理性,更有利于诊断及观察乳腺癌。
文摘针对经典的最小方差无畸变响应波束形成器应用在FDA-BFF(Frequency Diverse Array Based On Fre-quency Filter,FDA-BFF)及FDA-MIMO(Frequency Diverse Array Multiple-Input Multiple-Output,FDA-MIMO)接收机结构时,当阵元数较大或干扰与目标角度维接近时波束主瓣会产生峰值畸变或偏移,波束形成器输出性能下降,无法有效确定目标位置的问题,提出了基于双边小方差无畸变响应的子阵频控阵波束形成算法。该算法将一维均匀线性阵列划分为两个采用不同非线性频偏的中心对称子阵结构,在目标位置形成点状波束,对传统频偏固定的频控阵方向图中的距离-角度实现解耦。之后,通过双边小方差无畸变响应算法中求解克罗内克积的方式降低了算法计算量。仿真验证表明,阵元数较大时该算法在目标位置处形成点状波束的同时,可以有效抑制角度维不可分的干扰。
