Beam alignments based on the spectrum decomposition of orbital angular momentums for acoustic-vortex communications

Given the enhanced channel capacity of wave chirality, acoustic communications based on the orbital angular momentum (OAM) of acoustic-vortex (AV) beams are of significant interest for underwater data transmissions. However, the stringent beam alignment is required for the coaxial arrangement of transceiver arrays to ensure the accuracy and reliability of OAM decoding. To avoid the required multiple measurements of the traditional orthogonality based algorithm, the beam alignment algorithm based on the OAM spectrum decomposition is proposed for AV communications by using simplified ring-arrays. Numerical studies of the single-OAM and OAM-multiplexed AV beams show that the error of the OAM spectrum increases with the translation distance and the deflection angle of the transceiver arrays. To achieve an ideal arrangement, two methods of the single-array translation alignment and the dual-array deflection alignment are developed based on the least standard deviation of the OAM spectrum (SD-OAM). By decreasing the SD-OAM towards zero using transceiver arrays of 16 transmitters and 16 receivers, accurate beam alignments are accomplished by multiple adjustments in three dimensions. The proposed method is also demonstrated by experimental measurements of the OAM dispersion and the SD-OAM for misaligned beams. The results demonstrate the feasibility of the rapid beam alignment based on the OAM spectrum decomposition by using simplified transceiver ring-arrays, and suggest more application potentials for acoustic communications.     

橙皮中橙皮苷的分光光度法测定

建立了分光光度测定橙皮中橙皮苷含量的简便方法。橙皮苷和Al(NO3)3水溶液反应后生成的络合物在420nm处有最大吸收,在0—100μg/mL的浓度范围内吸光度具有良好的线性关系。可用于分光光度测定橙皮中橙皮苷。方法简单、快速,具有处理量大的优点。     

稀疏孔径光学系统成像的图像恢复算法研究

提出两种稀疏孔径光学系统成像的图像恢复模型.分析维纳滤波、最小二乘方滤波和极大似然法盲去卷积三种图像恢复算法的适用条件.针对存在噪声干扰的稀疏孔径光学系统,通过实验对比,指出维纳滤波和最小二乘方滤波把相机光学传函当作系统传函,其理论推导能够达到最优.盲去卷积把大气传输函数和相机光学传函作为系统传函进行恢复,其恢复结果优于维纳滤波带入常数K和最小二乘方滤波调整参量结果.     

Non-parametric reconstruction of dark energy and cosmic expansion from the Pantheon compilation of type Ia supernovae

The equation of state(EoS) of dark energy plays an important role in the evolution of the universe and has attracted considerable interest in the recent years. With the progress in observational technique, a precise constraint on the EoS of dark energy can be obtained. In this study, we reconstruct the EoS of dark energy and cosmic expansion using Gaussian processes(GP) from the most up-to-date Pantheon compilation of type Ia supernovae(SNe Ia),which consists of 1048 finely calibrated SNe Ia. The reconstructed EoS of dark energy has a large uncertainty owing to its dependence on the second-order derivative of the construction. Adding the direct measurements of Hubble parameters H(z) as an additional constraint on the first-order derivative can partially reduce the uncertainty; however, it is still not sufficiently precise to distinguish between the evolving and the constant dark energy. Moreover, the results heavily rely on the prior of the Hubble constant H0. The H0 value inferred from SNe+ H(z) without prior is H0= 70.5 ± 0.5 km s~(-1) Mpc~(-1). Moreover, the matter density ?M has a non-negligible effect on the reconstruction of dark energy. Therefore, more accurate determinations on H_0 and ?_M are required to tightly constrain the EoS of dark energy.     

Local probes strongly favor ΛCDM against power-law and R_h=ct universe

We constrain three cosmological models – the concordance cold dark matter plus cosmological constant(ΛCDM) model, the power-law(PL) model, and the Rh =ct model – using the available local probes, which include the JLA compilation of type-Ia supernovae(SNe Ia), the direct measurement of the Hubble constant(H_(z)), and the baryon acoustic oscillations(BAO). For the ΛCDM model, we consider two different cases, i.e. zero and non-zero spatial curvature. We find that by using the JLA alone, the ΛCDM and PL models are indistinguishable, but the Rh =ct model is strongly disfavored. If we combine JLA+H_(z), the ΛCDM model is strongly favored over the other two models. The combination of all three datasets supports ΛCDM as the best model. We also use the low-redshift(z 0.2) data to constrain the deceleration parameter using the cosmography method, and find that only the ΛCDM model is consistent with cosmography. However, there is no strong evidence to distinguish between flat and non-flatΛCDM models by using the local data alone.     

Optical and Structural Properties of Mn-Doped GaN Grown by Metal Organic Chemical Vapour Deposition

Mn-doped GaN epitaxial films were grown by metal organic chemical vapour deposition （MOCVD）. Microstructural properties of films are investigated using Raman scattering. It is found that with increasing Mn-dopants levels, longitudinal optical phonon mode A1 （LO） of films is broadened and shifted towards lower frequency. This phenomenon possibly derives from the difference in bonding strength between Ga-N pairs and Mn-N pairs in host lattice. In addition, optical properties of films are investigated using cathodoluminescence and absorption spectroscopy. Mn-related both emission band around 3.0eV and absorption bands around 1.5 and 2.95eV are observed. By studies on structural and optical properties of Mn-doped GaN, we find that Mn ions substitute for Ga sites in host lattice. However, carrier-mediated ferromagnetic exchange seems unlikely due to deep levels of Mn acceptors.     

8-羟基喹啉与醋酸钴固相配位反应的热化学研究

用具有恒定温度环境的反应热量计,以 ４ ｍ ｏｌ· Ｌ－ １ Ｈ Ｃｌ溶液为量热溶剂,测得８羟基喹啉与醋酸钴固相反应焓Δｒ Ｈｍ ＝ ２９．６８ ｋ Ｊ·ｍ ｏｌ－ １,计算了配合物 Ｃｏ（ｏｘｉｎ）２ ·２ Ｈ２ Ｏ 的标准生成焓Δｆ Ｈｍ ＝ － ７６４．６ ｋ Ｊ·ｍ ｏｌ     

镨对锌单取代杂多化合物气相扩渗的电性能及XPS研究

报道了采用气相法对K7ZnBW11O39配合物进行Pr的化学热扩渗, 研究了材料的电性能, 并结合XPS等表征手段对其导电机理加以了初步的分析. 通过配合物的TG-DTA分析确定了扩渗温度,扩渗后材料的ICP分析测试表明, 微量Pr可渗入到试样中. 经XRD分析发现, 扩渗后,化合物的晶型发生了改变, 得到了新的化合物. 利用四电极法和交流阻抗法对扩渗前后样品的导电性能进行了测试, 结果表明材料的导电性能发生了十分显著的变化, 扩渗后试样的电导率为2.98×10-2 S*cm-1, 比扩渗前的电导率3.54×10-6 S*cm-1提高了约104倍. XPS能谱及交流阻抗谱分析显示可能存在氧空穴导电.     

二水醋酸镉与邻氨基苯甲酸的分步固相反应的热化学研究

用溶解量热法,以一定比例的盐酸(0.2mol·L     

四水氯化锰与对甲基苯胺配位反应的热化学研究

用溶解量热法测定聚凝相反应的焓变,并进一步得到指定物质未见报道的标准生成焓数据,是一种较准确的研究手段。所得到结果可完善物质的标准热力学性质,满足化学研究与应用的需要。本文选择氯化锰（NnCl2.4H2O)与对甲基苯胺（CH3C6H4NH2,简称p-tol)进行反应,合成了配合物Mn(p-tol)2Cl2。用新型的具有恒定温度环境的反应热量计^[1],以溶解量热法^[2,3],用一定比例的HCl(3.0mol.L^-1)与无水乙醇的合溶液作为量热溶剂,分别测定了反应物,产物的溶解熔,设计了一个新的热化学循环,得到了配位反应的反应焓,并计算出了配合物Mn(p-tol)2Cl2的标准生成焓。