CDMA-800MHz频段低温低驻波比放大电路设计

为用HEMT晶体管设计L波段低驻波比放大电路,本文用输入无源复反射系数在输出反射平面上的共轭匹配区表达式,将驻波比约束转化为无源匹配区域的映射.同时为了计算放大电路低温下噪声,通过有损输入模型导出了噪声的温度关系式.实测CDMA-830MHz高温超导前端放大器噪声温度小于30K,输入驻波比小于1.3,输出驻波比小于1.8,增益大于17dB.     

Synthesis,characterization, potentiometry,and antimicrobial studies of transition metal complexes of a tridentate ligand

Complexes of Cu(II), Ni(II), Co(II), Mn(II), and Fe(III) with the tridentate Schiff base, 4-hydroxy-3(1-{2-(benzylideneamino)-phenylimino}-ethyl)-6-methyl-2H-pyran-2-one (HL) derived from 3-acetyl-6-methyl-(2H)-pyran-2,4(3H)-dione (dehydroacetic acid or DHA), o-phenylenediamine, and benzaldehyde were characterized by elemental analysis, molar conductivity, magnetic susceptibility, thermal analysis, X-ray diffraction, IR, ¹H-NMR, UV-Vis spectroscopy, and mass spectra. From analytical data, the stiochiometry of the complexes was found to be 1?:?2 (metal?:?ligand) with octahedral geometry. The molar conductance values suggest nonelectrolytes. X-ray diffraction data suggest monoclinic crystal systems. IR spectral data suggest that the ligand is dibasic tridentate with ONN donors. To investigate the relationship between formation constants of metal complexes and antimicrobial activity, the dissociation constants of Schiff base and stability constants of its binary metal complexes have been determined potentiometrically in THF–water (60?:?40) at 30?±?1°C and at 0.1?mol?L^?1 NaClO₄ ionic strength. The potentiometric titrations suggest 1?:?1 and 1?:?2 complexation. Antibacterial and antifungal activities in vitro were performed against Staphylococcus aureus, Escherichia coli, Aspergillus niger, and Trichoderma with determination of minimum inhibitory concentrations of ligand and metal complexes. The structure–activity correlation based on stability constants of metal complexes is discussed. Activity enhances upon complexation and the order of activity is in accord with the stability order of metal ions.     

Synthesis,characterization, semi-empirical study,and biological activities of organotin(IV) complexes with cyclohexylcarbamodithioic acid as biological active ligand

Cyclohexylcarbamodithioic acid has been synthesized by the reaction of cyclohexylamine with carbon disulfide at room temperature. Its complexes have been synthesized by the reaction of cyclohexylcarbamodithioic acid with organotin(IV) chlorides in 1?:?1/1?:?2 molar ratio. The ligand and complexes have been characterized by elemental analysis, infrared (IR), and multinuclear (¹H, ¹³C, and ¹¹⁹Sn) NMR spectroscopy. Elemental data show good agreement between calculated and found values of carbon, hydrogen, nitrogen, and sulfur. IR data show that the ligand is bidentate and complexes exhibit a five-coordinate geometry in the solid state, which is also confirmed by semi-empirical studies. NMR data show that the complexes exhibit tetrahedral geometry in solution state. The ligand and its complexes were screened for their in vitro mutagenic, antimicrobial, MIC, antioxidant activities, and cytotoxicity. Biological screening data demonstrate that complexes show significant activity against various bacterial and fungal strains and are good antioxidants. The cytotoxicity data show positive lethality for complexes as compared to ligand and can play a very significant role in drug development.     

Studies on Antimicrobial Evaluation of Some 1-((1-(1H-Benzo[d]imidazol-2-yl)ethylidene)amino)-6-((arylidene)amino)-2-oxo-4-phenyl-1, 2-dihydropyridine-3,5-dicarbonitriles

A new series of 1-((1-(1H-benzo[d]imidazol-2-yl)ethylidene)amino)-6-((arylidene)amino)-2-oxo-4-phenyl-1,2-dihydropyridine-3,5-dicarbonitriles (4a–o) have been synthesized for the development of antimicrobial agents. Newly synthesized compounds were evaluated for their in vitro antibacterial activity against Gram-positive bacteria (Pseudomonas aeruginosa, Streptococcus pyogenes), Gram-negative bacteria (Escherichia coli, Staphylococcus aureus), and antifungal activity (Candida albicans, Aspergillus niger, Aspergillus clavatus). These compounds were characterized by infrared, ¹H NMR, ¹³C NMR, and mass spectra. The synthesized compounds 4b, 4e, 4 h, and 4k showed potent antimicrobial activity against tested microorganisms.     

A Specially Designed Modulation-Induced Cyclostationarity Scheme for Blind SISO Channel Identification and Equalization

A special Modulation-Induced Cyclostationarity(MIC)scheme is designed for the identification and equaliza-tion of FIR Single-Input-Single-Output(SISO)channel,with the property that the transmit power is constant and the re-ceiver needs only one antenna.The cyclic Wiener equalizer is presented based on the estimated channel.     

八位串行输入锁定驱动器MIC5841/MIC5842及其应用

MIC5841/5842是MICREL公司采用BiCMOS工艺技术生产的可驱动多种外围功率应用系统的完整8位串行输入驱动器集成电路。它内含8-bitCMOS移位寄存器、CMOS控制电路、8个CMOS数据锁存器和8个双极型电流阻断式复合晶体管输出驱动器 ,可用于驱动照明灯以及继电器、螺线管和其它感性负载。文中介绍了它的主要特点、引脚排列、内部结构和主要参数,同时给出了MIC5841/MIC5842的典型应用电路     

Exploration of the Antimicrobial Effects of Benzothiazolylthiazolidin-4-One and In Silico Mechanistic Investigation

Background: Infectious diseases still affect large populations causing significant morbidity and mortality. Bacterial and fungal infections for centuries were the main factors of death and disability of millions of humans. Despite the progress in the control of infectious diseases, the appearance of resistance of microbes to existing drugs creates the need for the development of new effective antimicrobial agents. In an attempt to improve the antibacterial activity of previously synthesized compounds modifications to their structures were performed. Methods: Nineteen thiazolidinone derivatives with 6-Cl, 4-OMe, 6-CN, 6-adamantan, 4-Me, 6-adamantan substituents at benzothiazole ring were synthesized and evaluated against panel of four bacterial strains S. aureus, L. monocytogenes, E. coli and S. typhimirium and three resistant strains MRSA, E. coli and P. aeruginosa in order to improve activity of previously evaluated 6-OCF₃-benzothiazole-based thiazolidinones. The evaluation of minimum inhibitory and minimum bactericidal concentration was determined by microdilution method. As reference compounds ampicillin and streptomycin were used. Results: All compounds showed antibacterial activity with MIC in range of 0.12–0.75 mg/mL and MBC at 0.25–>1.00 mg/mL The most active compound among all tested appeared to be compound 18, with MIC at 0.10 mg/mL and MBC at 0.12 mg/mL against P. aeruginosa. as well as against resistant strain P. aeruginosa with MIC at 0.06 mg/mL and MBC at 0.12 mg/mL almost equipotent with streptomycin and better than ampicillin. Docking studies predicted that the inhibition of LD-carboxypeptidase is probably the possible mechanism of antibacterial activity of tested compounds. Conclusion: The best improvement of antibacterial activity after modifications was achieved by replacement of 6-OCF₃ substituent in benzothiazole moiety by 6-Cl against S. aureus, MRSA and resistant strain of E. coli by 2.5 folds, while against L. monocytogenes and S. typhimirium from 4 to 5 folds.     

Chemical, spectroscopic characterization, DFT studies and initial pharmacological assays of a silver(I) complex with N-acetyl-l-cysteine

A new silver(I) complex with N-acetyl-l-cysteine (NAC) of composition AgC₅H₈NO₃S·H₂O was synthesized and characterized by a set of chemical and spectroscopic measurements. Solid-state ¹³C nuclear magnetic resonance (SSNMR) and infrared (IR) analyses indicate the coordination of the ligand to Ag(I) through the sulfur atom. The Ag-NAC complex is slightly soluble in dimethyl sulfoxide. It is insoluble in water, methanol, ethanol, acetone and hexane. Antibacterial activity of the silver complex with N-acetyl-l-cysteine (Ag-NAC) was evaluated by antibiogram assays using the disc diffusion method. The compound showed an effective antibacterial activity against Staphylococcus aureus (Gram-positive), Escherichia coli and Pseudomonas aeruginosa (Gram-negative) bacterial cells. Biological analysis for evaluation of a potential cytotoxic effect of Ag-NAC was performed using HeLa cells derived from human cervical adenocarcinoma. The complex presented a significant cytotoxic activity, inducing 80% of cell death at a concentration of 200 μmol L⁻¹.     

Characterization of peptide–protein interactions using photoaffinity labeling and LC/MS

The combination of photoaffinity labeling (PAL) with modern mass spectrometric techniques is a powerful approach for the characterization of peptide–protein interactions. Depending on the analytical strategy applied, a PAL experiment can provide different levels of information ranging from the identification of interaction partners to the structural characterization of ligand-binding sites. On the basis of LC/MS data generated in the framework of the identification of the binding site of the neuropeptide corticotropin-releasing factor (CRF) on its binding protein (CRFBP), the key role of LC/MS in the characterization of photoadducts on different structural levels was demonstrated. Covalent photoadducts of rat CRFBP (rCRFBP) were obtained by PAL with different mono- and bifunctional benzophenone photoprobes designed on the basis of the sequence of the synthetic CRF fragment human/rat CRF^6–33 which binds to CRFBP with high affinity. In view of the stoichiometry, LC/MS analysis revealed that the photoadducts consisted of one molecule of photoprobe and one molecule of rCRFBP. For a further characterization of the photoadducts on the oligopeptide level, enzymatic digests of unlabeled rCRFBP and of the respective photoadduct were compared by peptide mapping monitored with LC/MS. Thereby, it was found that the photoprobe that contained the photophore at its N-terminus labeled the amino acid sequence rCRFBP(34–38), whereas the photoprobe that contained the photophore at its C-terminus labeled rCRFBP(12–26). On the basis of the characterization of the photoadduct formed by rCRFBP and the bifunctional photoprobe that contained photophores on both termini, semiquantitative comparison of different enzymatic digests was accomplished by application of the mass-selective multiple ion chromatogram strategy.