Further studies on thickness vibrations of piezoelectric plate excited by parallel field

I.IntroductionThcthickncssvibrationsofahomogeneous-anisotropicpiezoclectriccrystalplatewithanexcitingficldparallcltothemajorsurfacesofthep1ate,andalsototheplanewavefront(calledasthepara11e1fic1dcxcitatloninbricO,havebccnana1yzedI'1.Theprimarybehaviourofthick-nessvibrationshasbecnobtaincdasthepIatewitharbitraryorientationisexcitedbythepara11elfield.Inthispapcr,wcwillgofurthcrtogivcancwformu1aofthemechanicalresonantfrequen-cyequation.ILqformisthesameasthercsonantequationofthepuremodeandiseasyt…     

Optical readout method for microcantilever array sensing and its sensitivity analysis

An optical readout platform using a knife-edge filter for detecting the bending of a bimaterial microcantilever array is established, and the influence of stress-induced micromirror deformation on the optical detection sensitivity is discussed. The influence of deformation is modeled theoretically and validated experimentally. Analysis shows that the optical detection sensitivity will decrease by 50% when the mirror has a deformation of lambda/5 (lambda is the wavelength of readout light). Finally, an infrared image is obtained by the platform.     

Novel and Potent Acetylcholinesterase Inhibitors for the Treatment of Alzheimer’s Disease from Natural (±)-7,8-Dihydroxy-3-methyl-isochroman-4-one

Alzheimer’s disease (AD) is a neurodegenerative disease that causes memory and cognitive decline as well as behavioral problems. It is a progressive and well recognized complex disease; therefore, it is very urgent to develop novel and effective anti-AD drugs. In this study, a series of novel isochroman-4-one derivatives from natural (±)-7,8-dihydroxy-3-methyl-isochroman-4-one [(±)-XJP] were designed and synthesized, and their anti-AD potential was evaluated. Among them, compound 10a [(Z)-3-acetyl-1-benzyl-4-((6,7-dimethoxy-4-oxoisochroman-3-ylidene)methyl)pyridin-1-ium bromide] possessed potent anti-acetylcholinesterase (AChE) activity as well as modest antioxidant activity. Further molecular modeling and kinetic investigations revealed that compound 10a was a dual-binding inhibitor that binds to both catalytic anionic site (CAS) and peripheral anionic site (PAS) of the enzyme AChE. In addition, compound 10a exhibited low cytotoxicity and moderate anti-Aβ aggregation efficacy. Moreover, the in silico screening suggested that these compounds could pass across the blood–brain barrier with high penetration. These findings show that compound 10a was a promising lead from a natural product with potent AChE inhibitory activity and deserves to be further developed for the prevention and treatment of AD.     

Theoretical studies on the structures and electronic spectra of C75B−

Intermediate neglect of differential overlap (INDO) calculations were used to study the structure of C₇₅B^?—the isoelectronic molecule of C₇₆. It was found that the boron atom mainly substitutes the second carbon atom (there are 19 types of carbon atoms in C₇₆). The electronic spectra of all the possible isomers of C₇₅B^? were calculated based on the optimized geometries. It was shown that the UV‐Vis spectra of C₇₅B^? and C₇₆ resemble each other in many ways with the exception of the absorptions beyond 700 nm. The red shift of the absorptions was rationalized and nature of transition of the peaks discussed. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003     

An Optical Readout Method Based Uncooled Infrared Imaging System

This paper presents an optical readout method based uncooled infrared imaging system that contains an optical read-out section and a bi-material micro-cantilever arrays (BMCA) detector. The optical read-out section is based on incoherent light spatial filter technique. The read-out section converts the deflection angles of BMCA caused by absorption of infrared (IR) radiation to a visible image through optical filtering operation of the BMCA with a knife-edge filter. A spatial mathematical model is presented to describe the read-out method and its validity is proved. The IR image of a person’s hand obtained through the using of the 100 × 100 BMCA and the 12-bit A/D quantizer demonstrates the ability of the system to create image. The performance test shows that the average Noise-equivalent temperature difference (NETD) of the imaging system can arrive at about 183mK with some areas having a NETD as low as 78mK. Project supported by Natural Science Foundation of China (No.60576053), National Technology Research and Development Program of China (No.2007AA03Z333).     

晶相可控的ZrO2纳米线的无卤制备及表征

采用无卤法制备晶相可控的ZrO₂纳米线. 通过静电纺丝法制备聚乙烯吡咯烷酮(PVP)与Zr(NO₃)₄的复合纤维; 再通过煅烧法在除去聚合物模板的同时制备ZrO₂纳米线. 采用X射线衍射(XRD)、 扫描电子显微镜(SEM)、 透射电子显微镜(TEM)、 傅里叶变换红外光谱(FTIR)仪及热重差热联用热分析仪(DSC-TGA)对材料的晶相结构、 形貌及热稳定性进行表征. 通过改变煅烧温度, 可以实现ZrO₂纳米材料形貌及晶相组成的调控.     

二氧化硫测定过程中烟气预处理器适用范围研究

建立了一种确定二氧化硫测定过程中烟气预处理器适用范围的方法。通过使用模拟烟气检测平台,分析了使用烟气预处理器条件下,湿度和二氧化硫设定浓度变化对二氧化硫浓度测定值及二氧化硫其损失的影响,确定了二氧化硫损失率小于5%时烟气预处理器的适用范围:二氧化硫含量大于91.9 mg/m3时,湿度不大于15.1%;二氧化硫含量在33.0~91.9 mg/m3之间时,湿度不大于10.4%。该方法有助于提高二氧化硫检测和排污总量核算的准确性。     

Biomass estimation of desert steppe based on spectral indices along a precipitation gradient

Abstract

Accurate estimation of grassland biomass in desert steppe is crucial for various studies such as grassland dynamic monitoring, scientific management, and environmental degradation. Observational tests were conducted in the Ordos desert steppe in July and August from 2014 to 2016 to measure the grassland biomass and grassland canopy spectral data along a precipitation gradient, to analyze the spectral reflectance characteristics and the correlation between different spectral indices and grassland biomass in the range of 350–1830?nm, and to establish and verify a model for estimating grassland biomass of desert steppe. The results showed that the spectral reflectance of the Ordos desert steppe is similar to the spectral characteristics of typical green vegetation. The spectral reflectance values of control and of lightly, medium-, and heavily degraded plots successively increased in the visible light band at 350–696?nm and decreased in the near-infrared band at 792–1349?nm. The sensitive band of the normalized difference spectrum indices after optimization was 705 and 710. The coefficient of determination of normalized difference spectral indices (705 and 710) and grassland biomass was R²?=?0.735. These values were significantly correlated at the p?R² values of the fitted power function model and the verification power function model were 0.764 and 0.746, respectively. The root mean square error was 41.59?g/m². The relative error was 28.37%, and the constructed power function model was the best model. Therefore, the optimized spectral indices can be used to effectively estimate the grassland biomass of desert steppe.     

Discovery of Norbornene as a Novel Hydrophobic Tag Applied in Protein Degradation

Hydrophobic tagging (HyT) is a potential therapeutic strategy for targeted protein degradation (TPD). Norbornene was discovered as an unprecedented hydrophobic tag in this study and was used to degrade the anaplastic lymphoma kinase (ALK) fusion protein by linking it to ALK inhibitors. The most promising degrader, Hyt-9 , potently reduced ALK levels through Hsp70 and the ubiquitin−proteasome system (UPS) in vitro without compensatory upregulation of ALK. Furthermore, Hyt-9 exhibited a significant tumor-inhibiting effect in vivo with moderate oral bioavailability. More importantly, norbornene can also be used to degrade the intractable enhancer of zeste homolog 2 (EZH2) when tagged with the EZH2 inhibitor tazemetostat. Thus, the discovery of novel hydrophobic norbornene tags shows promise for the future development of TPD technology.