Performance Analysis of Passive Magnetic Pointing Method for Implementation of Directional Antennas on CubeSats

Jin S. Kang,Jeffery T. King,Christopher R. Anderson,Michael H. Sanders 한국항공우주학회 2022 International Journal of Aeronautical and Space Sc Vol.23 No.4

As CubeSats have become hugely popular in the recent years, the demand on their capability has also increased. As the missions and functionalities become more complex, coupled with the popular VHF and UHF bands becoming less accessible, CubeSats have been getting pushed into using higher frequency bands. For more capable CubeSats such as NASA and military satellites, utilization of S- and X-band communication have become a common place. While S- and X-band communication provide much higher data rate for the mission, the power and attitude control demand has also increased. Meeting this increased cost and demand on resources may not be feasible for university-level projects as attitude control systems can often cost more than the rest of the CubeSat. This research revisits passive magnetic pointing as an option for providing antenna pointing capability for CubeSats, enabling S- and X-band communication without requiring an active attitude control system. CubeSats can make contact with ground stations located at higher latitude to establish data link with directional antennas. The analyses shows that a higher data throughput can be achieved using S- and X-band communication over the traditional 9600 bps link with the proposed setup, without requiring active attitude control or deployable solar panels. The study characterizes the expected communication link performance for a typical 3U CubeSat when implementing the proposed communication architecture using a S- or X-band patch antenna taking into consideration the expected pointing performance and power generation capability of a 3U CubeSat.

Drug-Resistant Pneumococcal Infections in the United States : A Problem for Clinicians, Laboratories, and Public Health

Simberkoff, Michael S. MediMedia Korea 1994 JAMA-Korea Vol.9 No.10

Halogen−π Interactions between Benzene and X₂/CX₄ (X = Cl, Br): Assessment of Various Density Functionals with Respect to CCSD(T)

Youn, Il Seung,Kim, Dong Yeon,Cho, Woo Jong,Madridejos, Jenica Marie L.,Lee, Han Myoung,Kołaski, Maciej,Lee, Joonho,Baig, Chunggi,Shin, Seung Koo,Filatov, Michael,Kim, Kwang S. American Chemical Society 2016 The Journal of physical chemistry A Vol.120 No.46

<P>Various types of interactions between halogen (X) and pi moiety (X-pi interaction) including halogen bonding play important roles in forming the structures of biological, supramolecular, and nanomaterial systems containing halogens and aromatic rings. Furthermore, halogen molecules such as X-2 and CX4 (X = Cl/Br) can be intercalated in graphite and bilayer graphene for doping and graphene functionalization/modification. Due to the X-pi interactions, though recently highly studied, their structures are still hardly predictable. Here, using the coupled-cluster with single, double, and noniterative triple excitations (CCSD(T)), the Moller-Plesset second-order perturbation theory (MP2), and various flavors of density functional theory (DFT) methods, we study complexes of benzene (Bz) with halogen-containing molecules X-2 and CX4 (X = Cl/Br) and analyze various components of the interaction energy using symmetry adapted perturbation theory (SAPT). As for the lowest energy conformers (S1), X-2-Bz is found to have the T-shaped structure where the electropositive X atom-end of X-2 is pointing to the electronegative midpoint of CC bond of the Bz ring, and CX4-Bz has the stacked structure. In addition to this CX4 Bz (S1), other low energy conformers of X-2-Bz (S2/S3) and CX4-Bz (S2) are stabilized primarily by the dispersion interaction, whereas the electrostatic interaction is substantial. Most of the density functionals show noticeable deviations from the CCSD(T) complete basis set (CBS) limit binding energies, especially in the case of strongly halogen-bonded conformers of X-2-Bz (S1), whereas the deviations are relatively small for CX4-Bz where the dispersion is more important. The halogen bond shows highly anisotropic electron density around halogen atoms and the DFT results are very sensitive to basis set. The unsatisfactory performance of many density functionals could be mainly due to less accurate exchange. This is evidenced from the good performance by the dispersion corrected hybrid and double hybrid functionals. B2GP-PLYP-D3 and PBE0-TS (Tkatchenko-Scheffler)/D3 are well suited to describe the X-pi interactions adequately, close to the CCSD(T)/CBS binding energies (within similar to 1 kJ/mol). This understanding would be useful to study diverse X-pi interaction driven structures such as halogen containing compounds intercalated between 2-dimensional layers.</P>

Direct Nonadiabatic Dynamics by Mixed Quantum-Classical Formalism Connected with Ensemble Density Functional Theory Method: Application to <i>trans</i>-Penta-2,4-dieniminium Cation

Filatov, Michael,Min, Seung Kyu,Kim, Kwang S. American Chemical Society 2018 Journal of chemical theory and computation Vol.14 No.9

<P>In this work, a direct mixed quantum-classical dynamics approach is presented, which combines two new computational methodologies. The nuclear dynamics is solved by the decoherence-induced surface hopping based on the exact factorization (DISH-XF) method, which is derived from the exact factorization of the electronic-nuclear wave function and correctly describes quantum decoherence phenomena. The state-interaction state-averaged spin-restricted ensemble-referenced Kohn-Sham (SI-SA-REKS, or SSR, for brevity) electronic structure method is based on ensemble density functional theory (eDFT) and provides correct description of real crossings between the ground and excited Born-Oppenheimer electronic states. The new combined approach has been applied to the excited-state nonadiabatic dynamics of the <I>trans</I>-penta-2,4-dieniminium cation (PSB3). The predicted S<SUB>1</SUB> lifetime of <I>trans</I>-PSB3, τ = 99 ± 51 fs, and the quantum yield of the cis conformation, ϕ = 0.63, agree with the results obtained previously in nonadiabatic molecular dynamics simulations performed with a variety of electronic structure methods and dynamics formalisms. Normal-mode analysis of the obtained classical nuclear trajectories suggests that only a few vibrational normal modes contribute to the nuclear wavepacket; where synchronization between several modes plays a dominant role for the outcome of photoisomerization.</P> [FIG OMISSION]</BR>

BREAKS IN THIN AND THICK DISKS OF EDGE-ON GALAXIES IMAGED IN THE<i>SPITZER</i>SURVEY OF STELLAR STRUCTURE IN GALAXIES (S⁴G)

Comeró,n, Sé,bastien,Elmegreen, Bruce G.,Salo, Heikki,Laurikainen, Eija,Athanassoula, E.,Bosma, Albert,Knapen, Johan H.,Gadotti, Dimitri A.,Sheth, Kartik,Hinz, Joannah L.,Regan, Michael W. IOP Publishing 2012 The Astrophysical journal Vol.759 No.2

<P>Breaks in the radial luminosity profiles of galaxies have until now been mostly studied averaged over disks. Here, we study separately breaks in thin and thick disks in 70 edge-on galaxies using imaging from the Spitzer Survey of Stellar Structure in Galaxies. We built luminosity profiles of the thin and thick disks parallel to midplanes and we found that thin disks often truncate (77%). Thick disks truncate less often (31%), but when they do, their break radius is comparable with that in the thin disk. This suggests either two different truncation mechanisms-one of dynamical origin affecting both disks simultaneously and another one only affecting the thin disk-or a single mechanism that creates a truncation in one disk or in both depending on some galaxy property. Thin disks apparently antitruncate in around 40% of galaxies. However, in many cases, these antitruncations are an artifact caused by the superposition of a thin disk and a thick disk, with the latter having a longer scale length. We estimate the real thin disk antitruncation fraction to be less than 15%. We found that the ratio of the thick and thin stellar disk mass is roughly constant (0.2 < M-T/M-t < 0.7) for circular velocities v(c) > 120 km s(-1), but becomes much larger at smaller velocities. We hypothesize that this is due to a combination of a high efficiency of supernova feedback and a slower dynamical evolution in lower-mass galaxies causing stellar thin disks to be younger and less massive than in higher-mass galaxies.</P>

THICK DISKS OF EDGE-ON GALAXIES SEEN THROUGH THE<i>SPITZER</i>SURVEY OF STELLAR STRUCTURE IN GALAXIES (S⁴G): LAIR OF MISSING BARYONS?

Comeró,n, Sé,bastien,Elmegreen, Bruce G.,Knapen, Johan H.,Salo, Heikki,Laurikainen, Eija,Laine, Jarkko,Athanassoula, E.,Bosma, Albert,Sheth, Kartik,Regan, Michael W.,Hinz, Joannah L.,de Pa IOP Publishing 2011 The Astrophysical journal Vol.741 No.1

<P>Most, if not all, disk galaxies have a thin (classical) disk and a thick disk. In most models thick disks are thought to be a necessary consequence of the disk formation and/or evolution of the galaxy. We present the results of a study of the thick disk properties in a sample of carefully selected edge-on galaxies with types ranging from T = 3 to T = 8. We fitted one-dimensional luminosity profiles with physically motivated functions-the solutions of two stellar and one gaseous isothermal coupled disks in equilibrium-which are likely to yield more accurate results than other functions used in previous studies. The images used for the fits come from the Spitzer Survey of Stellar Structure in Galaxies (S(4)G). We found that thick disks are on average more massive than previously reported, mostly due to the selected fitting function. Typically, the thin and thick disks have similar masses. We also found that thick disks do not flare significantly within the observed range in galactocentric radii and that the ratio of thick-to-thin disk scale heights is higher for galaxies of earlier types. Our results tend to favor an in situ origin for most of the stars in the thick disk. In addition, the thick disk may contain a significant amount of stars coming from satellites accreted after the initial buildup of the galaxy and an extra fraction of stars coming from the secular heating of the thin disk by its own overdensities. Assigning thick disk light to the thin disk component may lead to an underestimate of the overall stellar mass in galaxies because of different mass-to-light ratios in the two disk components. On the basis of our new results, we estimate that disk stellar masses are between 10% and 50% higher than previously thought and we suggest that thick disks are a reservoir of 'local missing baryons.'</P>

THE THICK DISK IN THE GALAXY NGC 4244 FROM S⁴G IMAGING

Comeró,n, Sé,bastien,Knapen, Johan H.,Sheth, Kartik,Regan, Michael W.,Hinz, Joannah L.,Gil de Paz, Armando,Mené,ndez-Delmestre, Karí,n,Muñ,oz-Mateos, Juan-Carlos,Seibert, IOP Publishing 2011 The Astrophysical journal Vol.729 No.1

<P>If thick disks are ubiquitous and a natural product of disk galaxy formation and/or evolution processes, all undisturbed galaxies that have evolved during a significant fraction of a Hubble time should have a thick disk. The late-type spiral galaxy NGC 4244 has been reported as the only nearby edge-on galaxy without a confirmed thick disk. Using data from the Spitzer Survey of Stellar Structure in Galaxies (S(4)G) we have identified signs of two disk components in this galaxy. The asymmetries between the light profiles on both sides of the mid-plane of NGC 4244 can be explained by a combination of the galaxy not being perfectly edge-on and a certain degree of opacity of the thin disk. We argue that the subtlety of the thick disk is a consequence of either a limited secular evolution in NGC 4244, a small fraction of stellar material in the fragments which built the galaxy, or a high amount of gaseous accretion after the formation of the galaxy.</P>

Structural and Functional Relationships in Glaucoma Using Standard Automated Perimetry and the Humphrey Matrix

Seong Bae Park,Yoon Pyo Nam,Kyung Rim Sung,Michael S. Kook 대한안과학회 2009 Korean Journal of Ophthalmology Vol.23 No.3

Purpose: To evaluate and compare correlations between structural and functional loss in glaucoma as assessed by optical coherence tomography (OCT), scanning laser polarimetry (GDx VCC, as this was the model used in this study), standard automated perimetry (SAP), and the Humphrey Matrix (Matrix). Methods: Ninety glaucomatous eyes identified with SAP and 112 eyes diagnosed using Matrix were independently classified into six subgroups, either S1/M1 (MD>-6dB), S2/M2 (-12<MD<-6dB) or S3/M3 (MD<-12dB), according to the mean deviation (MD) of each test. Average and sectoral retinal nerve fiber layer (RNFL) thickness and percentage of abnormal classifications using the internal normative databases of OCT and GDx VCC were compared among the six subgroups. Results: In the SAP subgroups, RNFL thickness values obtained by OCT in the nasal and temporal quadrants and the inferior averages of GDx VCC did not differ between the S1 and S2 subgroups (p=0.137, 0.738 and 0.149, respectively). In the Matrix subgroups, no measurement parameters differed between the M1 and M2 groups except for the overall mean and average inferior RNFL thickness given by OCT and the NFI values of GDx VCC (p=0.013, 0.016 and 0.029, respectively). When abnormal classifications were compared, all measurement parameters, without exception, were significantly different in both the SAP and the Matrix subgroups. Conclusions: SAP subgroups showed a good correlation of structural and functional defects when assessed using OCT and GDx VCC. These correlations were weaker in the Matrix subgroups, especially in the early stages of glaucoma. Korean J Ophthalmol 2009;23:176-182

Chemically driven carbon-nanotube-guided thermopower waves

Choi, Wonjoon,Hong, Seunghyun,Abrahamson, Joel T.,Han, Jae-Hee,Song, Changsik,Nair, Nitish,Baik, Seunghyun,Strano, Michael S. Nature Publishing Group 2010 NATURE MATERIALS Vol.9 No.5

Theoretical calculations predict that by coupling an exothermic chemical reaction with a nanotube or nanowire possessing a high axial thermal conductivity, a self-propagating reactive wave can be driven along its length. Herein, such waves are realized using a 7-nm cyclotrimethylene trinitramine annular shell around a multiwalled carbon nanotube and are amplified by more than 10<SUP>4</SUP> times the bulk value, propagating faster than 2 m s<SUP>−1</SUP>, with an effective thermal conductivity of 1.28±0.2 kW m<SUP>−1</SUP> K<SUP>−1</SUP> at 2,860 K. This wave produces a concomitant electrical pulse of disproportionately high specific power, as large as 7 kW kg<SUP>−1</SUP>, which we identify as a thermopower wave. Thermally excited carriers flow in the direction of the propagating reaction with a specific power that scales inversely with system size. The reaction also evolves an anisotropic pressure wave of high total impulse per mass (300 N s kg<SUP>−1</SUP>). Such waves of high power density may find uses as unique energy sources.

Genome Wide Proteomics of ERBB2 and EGFR and Other Oncogenic Pathways in Inflammatory Breast Cancer

Zhang, Emma Yue,Cristofanilli, Massimo,Robertson, Fredika,Reuben, James M.,Mu, Zhaomei,Beavis, Ronald C.,Im, Hogune,Snyder, Michael,Hofree, Matan,Ideker, Trey,Omenn, Gilbert S.,Fanayan, Susan,Jeong, S American Chemical Society 2013 Journal of proteome research Vol.12 No.6

<P>In this study we selected three breast cancer cell lines (SKBR3, SUM149 and SUM190) with different oncogene expression levels involved in ERBB2 and EGFR signaling pathways as a model system for the evaluation of selective integration of subsets of transcriptomic and proteomic data. We assessed the oncogene status with reads per kilobase per million mapped reads (RPKM) values for ERBB2 (14.4, 400, and 300 for SUM149, SUM190, and SKBR3, respectively) and for EGFR (60.1, not detected, and 1.4 for the same 3 cell lines). We then used RNA-Seq data to identify those oncogenes with significant transcript levels in these cell lines (total 31) and interrogated the corresponding proteomics data sets for proteins with significant interaction values with these oncogenes. The number of observed interactors for each oncogene showed a significant range, e.g., 4.2% (JAK1) to 27.3% (MYC). The percentage is measured as a fraction of the total protein interactions in a given data set vs total interactors for that oncogene in STRING (Search Tool for the Retrieval of Interacting Genes/Proteins, version 9.0) and I2D (Interologous Interaction Database, version 1.95). This approach allowed us to focus on 4 main oncogenes, ERBB2, EGFR, MYC, and GRB2, for pathway analysis. We used bioinformatics sites GeneGo, PathwayCommons and NCI receptor signaling networks to identify pathways that contained the four main oncogenes and had good coverage in the transcriptomic and proteomic data sets as well as a significant number of oncogene interactors. The four pathways identified were ERBB signaling, EGFR1 signaling, integrin outside-in signaling, and validated targets of C-MYC transcriptional activation. The greater dynamic range of the RNA-Seq values allowed the use of transcript ratios to correlate observed protein values with the relative levels of the ERBB2 and EGFR transcripts in each of the four pathways. This provided us with potential proteomic signatures for the SUM149 and 190 cell lines, growth factor receptor-bound protein 7 (GRB7), Crk-like protein (CRKL) and Catenin delta-1 (CTNND1) for ERBB signaling; caveolin 1 (CAV1), plectin (PLEC) for EGFR signaling; filamin A (FLNA) and actinin alpha1 (ACTN1) (associated with high levels of EGFR transcript) for integrin signalings; branched chain amino-acid transaminase 1 (BCAT1), carbamoyl-phosphate synthetase (CAD), nucleolin (NCL) (high levels of EGFR transcript); transferrin receptor (TFRC), metadherin (MTDH) (high levels of ERBB2 transcript) for MYC signaling; S100-A2 protein (S100A2), caveolin 1 (CAV1), Serpin B5 (SERPINB5), stratifin (SFN), PYD and CARD domain containing (PYCARD), and EPH receptor A2 (EPHA2) for PI3K signaling, p53 subpathway. Future studies of inflammatory breast cancer (IBC), from which the cell lines were derived, will be used to explore the significance of these observations.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jprobs/2013/jprobs.2013.12.issue-6/pr4001527/production/images/medium/pr-2013-001527_0010.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/pr4001527'>ACS Electronic Supporting Info</A></P>