The 30 GHz solid state amplifier for low cost low data rate ground terminals

This report details the development of a 20-W solid state amplifier operating near 30 GHz. The IMPATT amplifier not only met or exceeded all the program objectives, but also possesses the ability to operate in the pulse mode, which was not called for in the original contract requirements. The ability to operate in the pulse mode is essential for TDMA (Time Domain Multiple Access) operation. An output power of 20 W was achieved with a 1-dB instantaneous bandwidth of 260 MHz. The amplifier has also been tested in pulse mode with 50% duty for pulse lengths ranging from 200 ns to 2 micro s with 10 ns rise and fall times and no degradation in output power. This pulse mode operation was made possible by the development of a stable 12-diode power combiner/amplifier and a single-diode pulsed driver whose RF output power was switched on and off by having its bias current modulated via a fast-switching current pulse modulator. Essential to the overall amplifier development was the successful development of state-of-the-art silicon double-drift IMPATT diodes capable of reproducible 2.5 W CW output power with 12% dc-to-RF conversion efficiency. Output powers of as high as 2.75 W has been observed. Both the device and circuit design are amenable to low cost production

Probing neutrino and Higgs sectors in SU(2)1×SU(2)2×U(1)YSU(2)_1 \times SU(2)_2 \times U(1)_Y model with lepton-flavor non-universality

The neutrino and Higgs sectors in the \mbox{SU(2)}_1 \times \mbox{SU(2)}_2 \times \mbox{U(1)}_Y model with lepton-flavor non-universality are discussed. We show that active neutrinos can get Majorana masses from radiative corrections, after adding only new singly charged Higgs bosons. The mechanism for generation of neutrino masses is the same as in the Zee models. This also gives a hint to solving the dark matter problem based on similar ways discussed recently in many radiative neutrino mass models with dark matter. Except the active neutrinos, the appearance of singly charged Higgs bosons and dark matter does not affect significantly the physical spectrum of all particles in the original model. We indicate this point by investigating the Higgs sector in both cases before and after singly charged scalars are added into it. Many interesting properties of physical Higgs bosons, which were not shown previously, are explored. In particular, the mass matrices of charged and CP-odd Higgs fields are proportional to the coefficient of triple Higgs coupling $\mu$. The mass eigenstates and eigenvalues in the CP-even Higgs sector are also presented. All couplings of the SM-like Higgs boson to normal fermions and gauge bosons are different from the SM predictions by a factor $c_h$, which must satisfy the recent global fit of experimental data, namely $0.995<|c_h|<1$. We have analyzed a more general diagonalization of gauge boson mass matrices, then we show that the ratio of the tangents of the $W-W'$ and $Z-Z'$ mixing angles is exactly the cosine of the Weinberg angle, implying that number of parameters is reduced by 1. Signals of new physics from decays of new heavy fermions and Higgs bosons at LHC and constraints of their masses are also discussed.Comment: 40 pages, 1 figure; Journal vesio

Validating foundry technologies for extended mission profiles

This paper presents a process qualification and characterization strategy that can extend the foundry process reliability potential to meet specific automotive mission profile requirements. In this case study, data and analyses are provided that lead to sufficient confidence for pushing the allowed mission profile envelope of a process towards more aggressive (automotive) applications.\ud \u

Cholesteatoma and family history: An international survey

Objective To explore the relative frequency of a family history of cholesteatoma in patients with known cholesteatoma, and whether bilateral disease or earlier diagnosis is more likely in those with a family history. Associations between cleft lip or palate and bilateral disease and age of diagnosis were also explored. Design An online survey of patients with diagnosed cholesteatoma was conducted between October 2017 and April 2019. Participants The sample consisted of patients recruited from two UK clinics and self‐selected respondents recruited internationally via social media. Main outcome measures Side of cholesteatoma, whether respondents had any family history of cholesteatoma, age of diagnosis and personal or family history of cleft lip or palate were recorded. Results Of 857 respondents, 89 (10.4%) reported a positive family history of cholesteatoma. Respondents with a family history of cholesteatoma were more likely to have bilateral cholesteatoma (P = .001, odds ratio (OR) 2.15, 95% confidence interval (CI) 1.35‐3.43), but there was no difference in the age of diagnosis (P = .23). Those with a history of cleft lip or palate were not more likely to have bilateral disease (P = .051, OR 2.71, CI 1.00‐7.38), and there was no difference in age of diagnosis (P = .11). Conclusion The relatively high proportion of respondents that reported a family history of cholesteatoma offers supporting evidence of heritability in cholesteatoma. The use of social media to recruit respondents to this survey means that the results cannot be generalised to other populations with cholesteatoma. Further population‐based research is suggested to determine the heritability of cholesteatoma

Cataract occurrence in Micropogonia furnieri (Desmarest, 1822) in the area between Capes Frio and Torres (23° S and 29° S), Brazil : investigation of causes and electrophoretic studies of total proteins of the eye lenses

The frequency and distribution of these specimens were analysed and the electrophoretic patterns of soluble eye-lens proteins were determined. This cataract is not of parasitic origin and was rare in specimens from the coastal area. In the lagunar region it occurs mainly in specimens of the River Baguacu from April to November

Growth changes after maxillary protraction in class III patients

published_or_final_versio

Risk of cervical cancer is not increased in Chinese carrying homozygous arginine at codon 72 of p53

Homozygous arginine at codon 72 (HA72) of p53 was found in 22% of normal cervices and 30.0% of cervical cancers and no significant difference was detected between normal and cervical cancer with or without HPV 16/18. There was no correlation between HA72 and risk of cervical cancer in Chinese.link_to_subscribed_fulltex

An effectual approach to online social networking in entrepreneurial marketing: an empirical research from small hospitality firms

Online social networking is considered a low-cost, effective and efficient approach for entrepreneurs to practice marketing. Using various types of the network has been established in the literature as crucial to the way in which entrepreneurs do business. It is suggested that small firms with limited sources can utilise the “affordable” marketing approach to enhance their competitive advantage through networking with customers which is essential for firms’ survival. While previous studies have explored how entrepreneurs use social media marketing, little evidence as to how they use effectual approach to utilise social media channels in their online networking activities. As such, our paper looks into entrepreneurial online social networks and how these networks are used among small firms to facilitate their marketing strategy. Our study has illustrated how entrepreneurs in small hospitality firms used social media as a tool to carrying out online networking activities from an effectual perspective. In doing so, we contribute to EM literature by enhancing our knowledge in entrepreneurs’ online networking activities from an effectual approach. As a working paper, we aim to further develop our work by conducting the main study stage with a more in-depth interview with entrepreneurs from a wider range of companies to explore more insightfully the effectual process toward online networking to facilitate entrepreneurial marketing