含银医疗器械质量检验中的几点建议

含银医疗器械因没有相应的国家标准和行业标准可依，企业注册质量标准技术要求不统一，给市场监管带来不便。本文对目前含银医疗器械质量检验过程中出现的问题进行了分析，并对质量技术要求及银含量检测方法提出了相应的建议。     

Development of a Flexible Metamaterial Film with High EM Wave Absorptivity by Numerical and Experimental Methods

The present study is intended to develop and test a cost-effective and efficient printing method for fabricating flexible metamaterial film with high electromagnetic wave absorptivity. The film can be easily applied to the surfaces with curved aspects. Firstly, numerical parametric study of the absorption characteristics of the film is performed for the range of frequency varying from 2.0 to 9.0 GHz based on commercial software package. Secondly, the flexible metamaterial films are fabricated, and experiments are conducted. The flexible metamaterial film consists of a flexible dielectric film made of polyimide (PI) and an array of split-ring resonators. The split-ring resonators of different geometric dimensions are fabricated on the PI film surface by using a silver nanoparticles ink jet printer. The performance of the flexible structure is then measured and dependence of operation frequency with higher absorptivity on the dimensions of the split-ring resonators is investigated. A comparison between the numerical and experimental data shows that the numerical predictions of the operation frequency with higher absorptivity closely agree with the experimental data.     

The Effect of Pore Structure on Impact Behavior of Concrete Hollow Brick,Autoclaved Aerated Concrete and Foamed Concrete

Porous concrete is an energy absorption material, which has been widely used in civil engineering, traffic engineering and disaster reduction engineering. However, the effect of pore structure on the impact behavior of the porous concrete is lacked. In this study, a series of drop-weight impact tests were carried out on three typical types of porous concrete, i.e., concrete hollow brick (CHB), autoclaved aerated concrete (AAC) and foamed concrete (FC), to investigate the effect of pore structures on their impact behavior. For comparison, static load tests were also conducted as references. According to the damage to the samples, the developments of impact force, strain, contact stress–strain relationship and absorbed energy during drop-weight during the impact test were measured and analyzed. The results show that the ratio between the peak impact stress and compressive strength of CHB was 0.44, while that of AAC and FC increased to about 0.6, indicating that the small and uniform pore structure in AAC and FC had a higher resistance against impact load than the hollow cavity of CHB. In addition, the elastic recovery strain in AAC increased by about 0.2% and its strain at peak contact stress increased by about 160% for a comparison of CHB, implying that a small open pore structure could enhance ductility. Besides, the peak contact stress of FC was close to that of AAC during impact loading, while the strain at peak contact stress of FC increased by about 36% compared with AAC, revealing that the closed-pore structure could further enhance the deformation potential. Correspondingly, the energy absorption rates of CHB, AAC and FC were 85.9 kJ/s, 54.4 kJ/s and 49.7 kJ/s, respectively, where AAC decreased by about 58% compared with CHB, and FC decreased by about 10% compared with AAC.     

Amorphous FeCoCrSiB Ribbons with Tailored Anisotropy for the Development of Magnetic Elements for High Frequency Applications

The ferromagnetic resonance (FMR) in the frequency range of 0.5 to 12.5 GHz has been investigated as a function of external magnetic field for rapidly quenched Fe₃Co₆₇Cr₃Si₁₅B₁₂ amorphous ribbons with different features of the effective magnetic anisotropy. Three states of the ribbons were considered: as-quenched without any treatment; after relaxation annealing without stress at the temperature of 350 °C during 1 h; and after annealing under specific stress of 230 MPa at the temperature of 350 °C during 1 h. For FMR measurements, we adapted a technique previously proposed and tested for the case of microwires. Here, amorphous ribbons were studied using the sample holder based on a commercial SMA connector. On the basis of the measurements of the reflection coefficient S_11, the total impedance including its real and imaginary components was determined to be in the frequency range of 0.5 to 12.5 GHz. In order to confirm the validity of the proposed technique, FMR was also measured by the certified cavity perturbation technique using a commercial Bruker spectrometer operating at X-band frequency of 9.39 GHz. As part of the characterization of the ribbons used for microwave measurements, comparative analysis was performed of X-ray diffraction, optical microscopy, transmission electron microscopy, inductive magnetic hysteresis loops, vibrating sample magnetometry, magneto-optical Kerr effect (including magnetic domains) and magnetoimpedance data for of all samples.     

Acoustic Metamaterials for Low-Frequency Noise Reduction Based on Parallel Connection of Multiple Spiral Chambers

Acoustic metamaterials based on Helmholtz resonance have perfect sound absorption characteristics with the subwavelength size, but the absorption bandwidth is narrow, which limits the practical applications for noise control with broadband. On the basis of the Fabry–Perot resonance principle, a novel sound absorber of the acoustic metamaterial by parallel connection of the multiple spiral chambers (abbreviated as MSC-AM) is proposed and investigated in this research. Through the theoretical modeling, finite element simulation, sample preparation and experimental validation, the effectiveness and practicability of the MSC-AM are verified. Actual sound absorption coefficients of the MSC-AM in the frequency range of 360–680 Hz (with the bandwidth Δf₁ = 320 Hz) are larger than 0.8, which exhibit the extraordinarily low-frequency sound absorption performance. Moreover, actual sound absorption coefficients are above 0.5 in the 350–1600 Hz range (with a bandwidth Δf₂ = 1250 Hz), which achieve broadband sound absorption in the low–middle frequency range. According to various actual demands, the structural parameters can be adjusted flexibly to realize the customization of sound absorption bandwidth, which provides a novel way to design and improve acoustic metamaterials to reduce the noise with various frequency bands and has promising prospects of application in low-frequency sound absorption.     

Structure of Randomly Distributed Nanochain Aggregates on Silicon Substrates: Modeling and Optical Absorption Characteristics

Nanoparticle aggregate structures allow for efficient photon capture, and thus exhibit excellent optical absorption properties. In this study, a model of randomly distributed nanochain aggregates on silicon substrates is developed and analyzed. The Gaussian, uniform, and Cauchy spatial distribution functions are used to characterize the aggregate forms of the nanochains and their morphologies are realistically reconstructed. The relationships between the structural parameters (thickness and filling factor), equivalent physical parameters (density, heat capacity, and thermal conductivity), and visible absorptivity of the structures are established and analyzed. All the above-mentioned parameters exhibit extreme values, which maximize the visible-range absorption; these values are determined by the material properties and nanochain aggregate structure. Finally, Al nanochain aggregate samples are fabricated on Si substrates by reducing the kinetic energy of the metal vapor during deposition. The spectral reflection characteristics of the samples are studied experimentally. The Spearman correlation coefficients for the calculated spectral absorption curves and those measured experimentally are higher than 0.82, thus confirming that the model is accurate. The relative errors between the calculated visible-range absorptivities and the measured data are less than 0.3%, further confirming the accuracy of the model.     

Calibration and response of an EMI scanner

Summary Computed tomography provides a measurement of the linear absorption coefficient of material in vivo. The precision and accuracy of the measurements of this parameter made by the EMI scanner have been investigated at all three recommended voltage settings of the machine. The relationship between the EMI number and the linear absorption coefficient was found to be linear despite the polychromatic nature of the X-ray beam. The spatial resolution of the machine and the response to materials at different depths within the section have also been investigated.     

微量元素与中老年人冠心病、高血压病等关系的研究

本文采用电感耦合等离子体-原子发射光谱法测定了乌鲁木齐地区冠心病、高血压病、高脂血症,眼底动脉硬化患者及正常人（共210例）发中7种微量元素及Mg的含量。结果表明：4种患者发中Zn含量均低;除眼底动脉硬化组外,Mg含量也降低;Zn／Cu除高血压病组外比值也低;冠心病与高血压患者的发Cd,冠心病组与高血压病组患者的发Fe均降低。Fisher判别分析的结果提示,发中的Mo、Mg、Cd、Fe含量与冠心病关系密切,Mg、Mo含量与高血压关系密切;Zn、Mg、Fe、Mo与高脂血症关系密切。其中Mo、Mg在各病例组中均起着负向或正向的作用。并用逐步回归方法分析了元素与年龄间的关系,建立了部分元素的回归方程。     

灯盏花素大鼠在体肠吸收动力学研究

目的 研究灯盏花素在大鼠肠道的吸收动力学。方法 进行大鼠在体肠循环灌流肠吸收实验，HPLC法测定灯盏花乙素，研究灯盏花素在小肠和结肠的吸收情况，并分别考察不同质量浓度和不同pH对小肠吸收的影响。结果胆管结扎与胆管不结扎的实验组之间，吸收速率常数（ka）和吸收百分率均有显著性差异，在小肠和结肠的ka分别为（0．1071±0．013O）和（0．0707±0．0089）h^-1；灯盏花素在不同质量浓度下，未发现饱和现象，其ka几乎保持不变，在pH6．0～7．4，灯盏花素的吸收不受pH的影响。结论 灯盏花素在小肠的吸收多于在结肠的吸收，其吸收机制为被动扩散，吸收过程为一级动力学过程，提示灯盏花素可以被制成口服缓释剂型。     

大鼠长期服苯妥英锌或苯妥英钠对体内锌铜代谢的影响

本文用原子吸收分光光度法测定了大鼠分别服用苯妥英锌和苯妥英钠13周后(每天剂量为12mg/kg体重),肝脏、全脑、齿龈和血清锌铜的含量。苯妥英锌使齿龈和肝脏锌分别增高80％和49％,全脑和血清锌分别降低39％和35％,而苯妥英钠使齿龈和肝脏锌分别降低70％和28％,血清锌增高41％。两药均使全脑和齿龈铜降低。