摘要：文章以STC89C52单片机为核心器件,结合HC-RS04超声波传感器、光敏电阻、定时器、ADC0832模数转换器、LCD1602液晶显示屏,设计了坐姿纠正系统。通过超声波传感器对用户与被测物体的距离进行实时监测,通过光敏电阻对所处环境的光照强度进行实时监测,并通过单片机处理收集到的数据。当测得的距离或者光照强度任意一者超出正常范围时,单片机通过驱动蜂鸣器报警,提醒用户注意纠正。同时,通过LCD1602显示屏实时显示测得的数据。详细研究了基于单片机的坐姿纠正系统设计的硬件电路和软件设计方案,运用Keil软件进行代码调试,运用Proteus进行软件仿真。功能测试证明,所设计的坐姿纠正系统能够在多种情况下正常工作。

摘要：村庄是自然、历史及文化等各要素共同凝结而成的文化单元。它不仅是不同族群代代生存繁衍的时空聚落,更是多元民族文化的生成沃土,是各民族活态文化传统绵延与承继的空间载体。近一个多世纪以来,伴随着救亡图存和乡村建设的时代步伐,关注和研究乡村成了中国知识分子的使命和责任。

摘要：目的:探究基弧区非球面设计角膜塑形镜矫正青少年近视伴中高度散光的疗效及其对眼表形态与泪液的影响。方法:选取2018-12/2020-03于本院接受治疗的近视伴中高度散光青少年患者232例464眼为研究对象,随机分为对照组(116例232眼)和观察组(116例232眼),对照组采用基弧区球面设计角膜塑形镜矫正,观察组采用基弧区非球面设计角膜塑形镜矫正。配戴12mo后,比较两组患者矫正效果,配戴前后客观视觉质量、眼表形态、泪液相关指标及并发症发生率。结果:与配戴前比较,两组患者配戴后裸眼视力(UCVA)、屈光度均明显改善,且观察组UCVA、屈光度均显著优于对照组(均P0.05);与配戴前比较,两组患者配戴后非侵入式泪膜破裂时间(NI-BUT)显著下降(P0.05),且配戴前后两组患者泪液基础分泌量及泪河高度均无差异(P>0.05)。观察组与对照组配戴后并发症发生率无差异(6.9%vs 6.0%,P>0.05)。结论:基弧区非球面设计角膜塑形镜矫正青少年近视伴中高度散光的矫正效果及客观视觉质量优于球面设计角膜塑形镜,而两种角膜塑形镜对眼表形态与泪液影响相当。

摘要：As feature size scales down, reliability issues like single event upset(SEU) have become serious for circuit and system designers, especially for those who work on memory and latch designs. In this paper, an improved SEU tolerant data cell design based on the Quatro-10 T cell is proposed. The introduced cell enhances the capability of SEU tolerance by weakening the key transistors in the feedback loop to block the effects of transient fault. Simulation results show that our proposed design achieves obvious higher resilience to SEU and better performance on speed and power dissipation at the expense of an increased area. The proposed cell is a fully SEU immune design with an amount of critical charge at least 7 times more than the Quatro-10 T cell and has the lowest Power Delay Product. It shows that our design is very suitable in high-performance circuit and system design.

摘要：为保证路基供热防冻胀系统的合理设计和节能运行控制,发展一种基于建筑热环境设计模拟工具包DeST(designer’s simulation toolkit)的寒区路基动态热负荷预测方法。在DeST软件中建立由一系列“路基微元”构成的计算模型,利用软件内置的气象模型、遮挡模型、光照模型模拟路基所处的气候环境、太阳辐照和地形条件;应用建筑分析模拟模块BAS(building analysis simulation module),通过状态空间法求解路基微元基础温度,通过预测值与实测值的校核保证计算精度;设置路基目标温度,完成热负荷的逐时计算。依托哈齐高铁DK221+150监测断面实测数据,对所述方法进行验证,结果表明,路基温度场计算值与实测值一致。案例路基的最大热负荷为945 W/m,冻结期平均热负荷为335 W/m。热负荷可以反映路基阴阳坡效应和沿深度的传热滞后效应。基于中国严寒和寒冷气候区23个城市的典型气象年数据,对高铁路基的热负荷进行区域统计分析,结果表明,最大热负荷范围为531 W/m~1338 W/m,并与纬度呈线性正相关关系。研究成果可为寒区路基冻害评价和供热方案设计提供参考。

摘要：Endmember extraction is a key step in the hyperspectral image analysis process. The kernel new simplex growing algorithm （KNSGA）, recently developed as a nonlinear alternative to the simplex growing algorithm （SGA）, has proven a promising endmember extraction technique. However, KNSGA still suffers from two issues limiting its application. First, its random initialization leads to inconsistency in final results; second, excessive computation is caused by the iterations of a simplex volume calculation. To solve the first issue, the spatial pixel purity index （SPPI） method is used in this study to extract the first endrnember, eliminating the initialization dependence. A novel approach tackles the second issue by initially using a modified Cholesky fac- torization to decompose the volume matrix into triangular matrices, in order to avoid directly computing the determinant tauto- logically in the simplex volume formula. Theoretical analysis and experiments on both simulated and real spectral data demonstrate that the proposed algorithm significantly reduces computational complexity, and runs faster than the original algorithm.

摘要：We propose an effective method to design the working parameters of a pulse-driven charge qubit implemented with double quantum *** is shown that intrinsic qubit population leakage to undesired states in the control and measurement process can be determined by the simulation of coherent dynamics of the qubit and minimized by choosing proper working parameters such as pulse *** result demonstrated here bodes well for future quantum gate operations and quantum computing applications.

摘要：在频率源芯片窄带应用时,输出信号有较好的积分均方根抖动性能(RMS jitter),需要压控振荡器(VCO)有较出色的相噪特性。通过分析VCO的结构特点,确定电感是影响片上VCO相位噪声的关键性因素,通过HFSS软件建模的方式,将高品质因素(Q)值的键合线电感引入到片上VCO设计中。采用0.18μm SiGe BiCMOS工艺,设计了整块频率源芯片,并着重优化了VCO输出信号的相位噪声。经过实测,在开环状态下,VCO输出信号为2.2GHz,在1 MHz频偏处的相位噪声为-136dBc/Hz;在环路带宽80kHz,芯片输出信号相噪2.2GHz时,整颗芯片输出信号的带内本底噪声为-220dBc/Hz,杂散为-70dBc,积分均方根抖动为207.666fs。

摘要：论文针对大型薄壁件旋转加工要求,设计了专用对接环支撑部件,以实现工件支撑和旋转驱动。在满足结构强度及刚度的前提下,对其进行了减重设计,同时利用有限元分析的方法,对减重前后的对接环结构进行了详细的机械性能对比。结果表明,对接环的结构设计及减重设计满足工件加工的要求。

摘要：文章通过对桂林旅游特色产品包装设计个案设计思路的分析,结合桂林旅游产品市场的现状分析,由点带面地阐述桂林文化特色在旅游产品包装设计中的开发应用,从而强调对地域文化在产品包装设计中的城市地理、城市文化开发的重要性。