Cryogenic Break-Junction Characterization of Single Organic Molecules

In this thesis, a cryogenic mechanically controllable break-junction (MCBJ) setup is developed and used for the characterization of single organic molecules at different temperatures. Molecules are the building blocks of life and among others responsible for charge transfer in biological processes,e.g. photosynthesis in plants and metabolism in humans. Since these processes are not yet completely understood, single molecules are highly interesting systems to study. Furthermore, due to their astonishing properties they might be used as electronic components in future technologies. This approach is called “molecular electronics”, existing representatives that use thin or thick layers of organic molecules are for instance light emitting diodes (OLED) or liquid crystal displays (LCD). However, single molecule devices are still not in use, and in order to build such systems the single molecules have to be understood, especially their electronic properties. Since the size of single molecules is typically of the order of nm, their characterization requires an appropriate setup. In this thesis a MCBJ is developed that traps single molecules between two electrodes, and thus allows to characterize its electronic features. The first aim of this thesis is the construction and development of a cryogenic MCBJ setup, consisting mainly of three parts: (i) the sophisticated sample holder, suitable for measurements inside the helium-flow cryostat, including a piezo-positioner to bend the sample, (ii) an automated setup to control the measurement parameters and acquire the data (e.g. temperature, applied voltage, measured current, piezo-position), and (iii) the development of suitable break-junction samples consisting mainly of a lithographically prepared Au bridge (with nm size dimensions). The three parts together allow measurements of molecules with a position control in the pm regime, currents ranging from below pA to mA, and temperatures ranging from 4 K to room temperature. The second aim is to develop and to establish adequate procedures for break-junction measurements, regarding mounting of the sample, deposition of molecules and measurement techniques. For the latter one, conductance–position characteristics (CPCs), current–voltages characteristics(IVC), standard CPC histograms and contour histograms are developed, automated and tested in reference measurements without molecules. The third aim is the measurement of simple “test-bed” molecules. Hexanedithiol and benzenedithiol are chosen as representatives for simple alkanes and conjugated molecules, respectively. CPCs of the rod-like hexanedithiol show a distinct peak in agreement with literature values, while BeDT exhibits a more complex behavior. IVCs are performed on the molecules and molecular levels are obtained. The curves demonstrate the quality of the measurement techniques and the analysis methods. Finally, the fourth aim is the measurement of the temperature dependent electronic properties of the more complex molecules terphenyldithiol (TPT) and porphyrine (TPyP). The latter one plays an important role in biological processes and represents a promising candidate for molecular electronics. We find, that TPT exhibits a distinct and strongly temperature dependent conductance peak, while the level of the molecular orbital is independent of temperature. It is shown that for TPT a transition from direct tunneling to “hopping” mechanism takes place around a temperature of 100K. The TPyP displays unusual CPCs. Only tilted plateaus are observed, that are indicative for clustering of the molecule. Contour histograms demonstrate the presence of these clusters in the break-junction. IVCs of TPyP reveal a temperature dependent electronic or vibrational mode. It shifts towards higher voltages with increasing temperature and is therefore only detectable belowT $\lesssim$ 180K. Above this temperature reordering of the molecules and the molecule-Au bonds leadto large noise in the IVC at large voltages. The MCBJ represents an elegant way to detect interesting electronic properties of single molecules. Here, a major aspect is the great stability of the metal-molecule-metal system that allows extensive characterization even in the case of complex molecules. In this thesis it is shown, that lower temperatures improve the performance of the MCBJ, and, even more crucial, temperature dependent measurements allow a deeper insight in the charge transfer of single molecules

The multiplicity of massive stars in the Orion Nebula cluster as seen with long-baseline interferometry

The characterization of multiple stellar systems is an important ingredient for testing current star formation models. Stars are more often found in multiple systems, the more massive they are. A complete knowledge of the multiplicity of high-mass stars over the full range of orbit separations is thus essential to understand their still debated formation process. Observations of the Orion Nebula Cluster can help to answer the question about the origin and evolution of multiple stars. Earlier studies provide a good knowledge about the multiplicity of the stars at very small (spectroscopic) and large separations (AO, speckle) and thus make the ONC a good target for such a project. We used the NIR interferometric instrument AMBER at VLTI to observe a sample of bright stars in the ONC. We complement our data set by archival NACO observations of \theta 1 Ori A to obtain more information about the orbit of the close visual companion. Our observations resolve the known multiple systems \theta 1 Ori C and \theta 1 Ori A and provide new orbit points, which confirm the predicted orbit and the determined stellar parameters for \theta 1 Ori C. Combining AMBER and NACO data for \theta 1 Ori A we were able to follow the motion of the companion from 2003 to 2011. We furthermore find hints for a companion around \theta 1 Ori D and a previously unknown companion to NU Ori. With a probability of ~90% we can exclude further companions with masses of > 3 Msun around our sample stars for separations between ~2 mas and ~110 mas. We conclude that the companion around \theta 1 Ori A is most likely physically related to the primary star. The newly discovered possible companions further increase the multiplicity in the ONC. For our sample of two O and three B-type stars we find on average 2.5 known companions per primary, which is around five times more than for low-mass stars.Comment: accepted by A&

The multiplicity of massive stars in the Orion Nebula Cluster as seen with long-baseline interferometry

This is the final version of the article. Available from EDP Sciences via the DOI in this record.Context. The characterization of multiple stellar systems is an important ingredient for testing current star formation models. Stars are more often found in multiple systems, the more massive they are. A complete knowledge of the multiplicity of high-mass stars over the full range of orbit separations is thus essential to understand their still debated formation process. Aims. Infrared long baseline interferometry is very well suited to close the gap between spectroscopic and adaptive optics searches. Observations of the Orion Nebula Cluster (ONC) in general and the Trapezium Cluster in particular can help to answer the question about the origin and evolution of multiple stars. Earlier studies provide a good knowledge about the multiplicity of the stars at very small (spectroscopic companions) and large separations (AO, speckle companions) and thus make the ONC a good target for such a project. Methods. We used the near infrared interferometric instrument AMBER at ESOs Very Large Telescope Interferometer to observe a sample of bright stars in the ONC. We complement our data set by archival NACO observations of θ1 Ori A to obtain more information about the orbit of the close visual companion. Results. Our observations resolve the known multiple systems θ1 Ori C and θ1 Ori A and provide new orbit points, which confirm the predicted orbit and the determined stellar parameters for θ1 Ori C. Combining AMBER and NACO data for θ1 Ori A we were able to follow the (orbital) motion of the companion from 2003 to 2011. We furthermore find hints for a companion around θ1 Ori D, whose existence has been suggested already before, and a previously unknown companion to NU Ori. With a probability of ~90% we can exclude further companions with masses of ≥ 3 M⊙ around our sample stars for separations between ~2 mas and ~110 mas. Conclusions. We conclude that the companion around θ1 Ori A is most likely physically related to the primary star and not only a chance projected star. The newly discovered possible companions further increase the multiplicity in the ONC. For our sample of two O and three B-type stars we find on average 2.5 known companions per primary, which is around five times more than for low-mass stars. Key words: binaries:We gratefully acknowledge funding of this work by the German Deutsche Forschungsgemeinschaft, DFG project number PR 569/8-1. K.G.H. acknowledges support provided by the Proyecto FONDECYT Postdoctoral No. 3120153 and the Polish Nacional Science Center grant No. 2011/03/N/ST9/01819. This research has made use of the Jean-Marie Mariotti Center AMBER data reduction package3 and LITpro4 service co-developed by CRAL, LAOG and FIZEAU. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France. We thank the referee Douglas Gies for the helpful und constructive comments, which helped to improve the paper

relationships and interdependencies

Behavioral and personality characteristics are factors that may jointly regulate body weight. This study explored the relationship between body mass index (BMI) and self-reported behavioral and personality measures. These measures included eating behavior (based on the Three-Factor Eating Questionnaire; Stunkard and Messick, 1985), sensitivity to reward and punishment (based on the Behavioral Inhibition System/Behavioral Activation System (BIS/BAS) scales) (Carver and White, 1994) and self-reported impulsivity (based on the Barratt Impulsiveness Scale-11; Patton et al., 1995). We found an inverted U-shaped relationship between restrained eating and BMI. This relationship was moderated by the level of disinhibited eating. Independent of eating behavior, BIS and BAS responsiveness were associated with BMI in a gender-specific manner with negative relationships for men and positive relationships for women. Together, eating behavior and BIS/BAS responsiveness accounted for a substantial proportion of BMI variance (men: ∼25%, women: ∼32%). A direct relationship between self-reported impulsivity and BMI was not observed. In summary, our results demonstrate a system of linear and non-linear relationships between the investigated factors and BMI. Moreover, body weight status was not only associated with eating behavior (cognitive restraint and disinhibition), but also with personality factors not inherently related to an eating context (BIS/BAS). Importantly, these relationships differ between men and women

Investigating Mobile Accessibility Guidance for People with Aphasia

The World Wide Web Consortium’s (W3C) Web Content Accessibility Guidelines (WCAG 2.0) have become widely accepted as the standard for web accessibility evaluation. This poster investigates how the mobile version of these guidelines caters for people with aphasia (PWA) by comparing the results from user testing against that of an audit using the guidelines. We outline the efficacy of the guidelines in the broader context of how they cater for various impairments and offer some recommendations for designing for people with aphasia

Fenologia e características agronômicas de cultivares de ameixeira (prunus sallcina lindl.) recomendadas para a Região serrana do RS.

CULTIVAR DE AMEIXEIRA AMARELINHA A planta é semi-vigorosa, de hábito de crescimento semi-aberto e muito produtiva. É medianamente suscetível à bacteriose. O fruto é de tamanho médio a grande, com epiderme amarela-esverdeada com manchas vermelhas e polpa amarela. Apresenta baixa exigência em frio. O período de floração, em Veranópolis, nas safras de 2000/01 a 2004/05 foi de 23/08 a 14/09 (2000/01), 10/08 a 31/08 (2001/02), 08/08 a 02/09 (2002/03), 11/09 a 29/09 (2003/04) e de 04/08 a 06/09 (2004/05). Já o período de colheita dessa cultivar, em Veranópolis, no período de 2000/01 a 2004/05 foi de 21/01 a 31/01 (2000/01), 09/01 a 18/01 (2001/02), 12/01 a 23/01 (2002/03), 10/01 a 22/01 (2003/04) e de 13/01 a 25/01 (2004/05). A produtividade foi alta, epiderme amarela-esverdeada com vermelho, polpa amarela, fruto redondo de tamanho médio a grande. CULTIVAR DE AMEIXEIRA AMÉRICA A planta é vigorosa, de hábito de crescimento aberto e com boa resistência à bacteriose. O fruto é de tamanho médio, apresenta epiderme vermelho-claro, com fundo e polpa amarela. Possui média exigência em frio. É originária de cruzamento entre Prunus munsoniana e Prunus salicina. O período de floração, em Veranópolis, nas safras de 2000/01 a 2004/05 foi de 24/08 a 14/09 (2000/01), 21/08 a 10/09 (2001/02), 21/08 a 19/09 (2002/03), 10/09 a 03/10 (2003/04) e de 14/08 a 13/09 (2004/05). Já o período de colheita dessa cultivar, em Veranópolis, no período de 2000/01 a 2004/05 foi de 10/12 a 21/12 (2000/01), 30/11 a 11/12 (2001/02), 05/12 a 17/12 (2002/03), 12/12 a 24/12 (2003/04) e de 24/11 a 14/12 (2004/05). A produtividade foi de média a alta, epiderme amarela-avermelhada, polpa amarela, fruto esférico-oblonga de tamanho médio. CULTIVAR DE AMEIXEIRA FRONTIER A planta é semi-vigorosa e de hábito de crescimento ereto. É suscetível à bacteriose. O fruto é grande, com epiderme e polpa de coloração vermelho-escuras. Apresenta média a alta exigência em frio. O período de floração, em Veranópolis, nas safras de 2000/01 a 2004/05 foi de 05/09 a 23/09 (2000/01), 24/08 a 11/09 (2001/02), 31/08 a 19/09 (2002/03), 22/09 a 14/10 (2003/04) e de 31/08 a 17/09 (2004/05). Já o período de colheita dessa cultivar, em Veranópolis, no período de 2000/01 a 2004/05 foi de 12/12 a 20/12 (2000/01), 02/12 a 12/12 (2001/02), 06/12 a 16/12 (2002/03), 06/12 a 14/12 (2003/04) e de 26/11 a 17/12 (2004/05). A produtividade foi baixa a média, epiderme vermelho escuro, polpa vermelha, fruto redondo de tamanho grsnde. CULTIVAR DE AMEIXEIRA GULF BLAZE Planta é semi-vigorosa, com hábito de crescimento aberto. Floração coincidente, em grande parte, com Gulf Ruby, podendo ser polinizada pela mesma. A manutenção inicia, geralmente, em meados de novembro, sendo a colheita muito próxima da cv. Irati. É de baixa necessidade em frio hibernal. O sabor é doce-ácido, mas com acidez e amargo na película. Os frutos têm bom tamanho. A polpa é amarela e a película vermelha. CULTIVAR DE AMEIXEIRA GULF RUBY A planta é semi-vigorosa, com ramos fortes e longos e de hábito de crescimento semi-aberto. As folhas são grandes, de coloração verde-clara. A floração é abundante ocorrendo sobre ramos mistos e esporões. Os frutos são de coloração vermelha, ovalados (semelhantes aos da cultivar Irati) e com lenticelas bem perceptíveis. A polpas é de coloração amarela se bem madura, medianamente doce e com pouca acidez. Possui baixa exigência em frio. O período de floração, em Veranópolis, nas safras de 2000/01 a 2004/05 não foi disponível (2000/01), 03/07 a 10/08 (2001/02), 21/07 a 08/08 (2002/03), 04/07 a 18/08 (2003/04) e de 02/07 a 13/08 (2004/05). Já o período de colheita dessa cultivar, em Veranópolis, no período de 2000/01 a 2004/05 foi não disponível em 2000/01, 30/10 a 15/11 (2001/02), 04/11 a 18/11 (2002/03), 06/11 a 22/11 (2003/04) e de 27/10 a 16/11 (2004/05). A produtividade foi média a alta, epiderme vermelha, polpa amarela, fruto redondo-ovalalado de tamanho médio. CULTIVAR DE AMEIXEIRA HARRY PICKSTONE A planta é vigorosa, de hábito de crescimento semi-aberto e muito produtiva. É altamente suscetível à bacteriose, devendo ser plantada em locais abrigados do vento. O fruto é de tamanho médio a grande, com epderme amarela-esverdeada com roxo e polpa amarela. Cultivar de baixa exigência em frio. O período de floração, em Veranópolis, nas safras de 2000/01 a 2004/05 foi de 23/08 a 14/09 (2000/01), 14/08 a 06/09 (2001/02), 24/08 a 16/09 (2002/03), 19/09 a 03/10 (2003/04) e de 17/08 a 07/09 (2004/05). Já o período de colheita dessa cultivar, em Veranópolis, no período de 2000/01 a 2004/05 foi de 15/01 a 23/01 (2000/01), 04/01 a 13/01 (2001/02), 06/01 a 16/01 (2002/03), 07/01 a 18/01 (2003/04) e de 06/01 a 20/01 (2004/05). A produtividade foi alta, epiderme amarela-esverdeada com roxo, polpa amarela, fruto cordiforme de tamanho médio a grande. CULTIVAR DE AMEIXEIRA IRATI A planta é vigorosa, com ramificações laterais curtas e folhas grandes, de coloração verde-clara. Apresenta resistência à bacterise, mas é suscetível à escaldadura. O fruto é de tamanho médio, com epiderme de cor vermelho-carmim. A polpa é amarela, mas quando muito madura torna-se vermelha. Apresenta baixa exigência em frio. O período de floração, em Veranópolis, nas safras de 2000/01 a 2004/05 foi de 22/08 a 08/09 (2000/01), 13/08 a 28/08 (2001/02), 14/08 a 04/09 (2002/03), 01/09 a 17/09 (2003/04) e de 23/07 a 25/08 (2004/05). Já o período de colheita dessa cultivar, em Veranópolis, no período de 2000/01 a 2004/05 foi de 30/11 a 12/12 (2000/01), 16/11 a 27/11 (2001/02), 20/11 a 04/12 (2002/03), 25/11 a 09/12 (2003/04) e de 10/11 a 08/12 (2004/05). A produtividade foi alta, epiderme vermelho-carmim, polpa amarela, fruto redondo-cordiforme de tamanho médio. CULTIVAR DE AMEIXEIRA LETÍCIA A planta apresenta vigor médio e porte semi-ereto. É resistente à bacteriose. O fruto é grande, muito atrativo, de excelente qualidade e boa conservação. A epiderme é de coloração vermelho-púrpura e a polpa amarela. Cultivar de média a alta exigência em frio. O período de floração, em Veranópolis, nas safras de 2000/01 a 2004/05 foi de 08/09 a 25/09 (2000/01), 07/09 a 26/09 (2001/02), 09/09 a 01/10 (2002/03), 03/10 a 18/10 (2003/04) e de 08/09 a 24/09 (2004/05). Já o período de colheita dessa cultivar, em Veranópolis, no período de 2000/01 a 2004/05 foi de 18/01 a 29/01 (2000/01), 06/01 a 17/01 (2001/02), 10/01 a 22/01 (2002/03), 14/01 a 22/01 (2003/04) e de 11/01 a 26/01 (2004/05). A produtividade foi de média a alta, epiderme vermelho-púrpura, polpa amarela, fruto redondo-cônico de tamanho grande. CULTIVAR DE AMEIXEIRA METHLEY A planta é vigorosa, semi-aberta e com boa resistência à bacteriose. O fruto é de tamanho pequeno, com epiderme e polpa vermelhas. Cultivar de média exigência em frio. O período de floração, em Veranópolis, nas safras de 2000/01 a 2004/05 foi de 29/08 a 16/09 (2000/01), 21/08 a 11/09 (2001/02), 25/08 a 16/09 (2002/03), 18/09 a 06/10 (2003/04) e de 23/08 a 17/09 (2004/05). Já o período de colheita dessa cultivar, em Veranópolis, no período de 2000/01 a 2004/05 foi de 30/11 a 11/12 (2000/01), 16/11 a 30/11 (2001/02), 23/11 a 03/12 (2002/03), 02/12 a 12/12 (2003/04) e de 24/11 a 14/12 (2004/05). A produtividade foi de média a alta, epiderme vermelho-rosa, polpa vermelha, fruto redondo de tamanho pequeno. CULTIVAR DE AMEIXEIRA PLUMA 7 A planta é vigorosa, semi-aberta e altamente suscetível à bacteriose. O fruto é de tamanho médio a grande, com epiderme e polpa de coloração vermelho-escura. Cultivar de baixa exigência em frio. O período de floração, em Veranópolis, nas safras de 2000/01 a 2004/05 foi de 16/08 a 06/09 (2000/01), 28/08 a 13/09 (2001/02), 19/08 a 06/09 (2002/03), 16/08 a 04/09 (2003/04) e de 20/08 a 04/09 (2004/05). Já o período de colheita dessa cultivar, em Veranópolis, no período de 2000/01 a 2004/05 foi de 20/12 a 03/01 (2000/01), 04/01 a 13/01 (2001/02), 21/12 a 3012 (2002/03), 20/12 a 28/12 (2003/04) e de 20/12 a 28/12 (2004/05). A produtividade foi de média a alta, epiderme vermelha, polpa vermelha, fruto redondo de tamanho médio a grande. CULTIVAR DE AMEIXEIRA POLLI ROSA É uma mutação da cultivar Santa Rosa, mais produtiva e menos exigente em frio. A planta apresenta vigor médio e hábito de crescimento ereto. O fruto é de tamanho médio, com epiderme vermelha e polpa amarela rosada. Cultivar de baixa exigência em frio. O período de floração, em Veranópolis, nas safras de 2000/01 a 2004/05 foi de 21/08 a 13/09 (2000/01), 14/08 a 05/09 (2001/02), 19/08 a 04/09 (2002/03), 05/09 a 29/09 (2003/04) e de 06/08 a 06/09 (2004/05). Já o período de colheita dessa cultivar, em Veranópolis, no período de 2000/01 a 2004/05 foi de 08/12 a 19/12 (2000/01), 20/11 a 04/12 (2001/02), 25/11 a 05/12 (2002/03), 12/12 a 24/12 (2003/04) e de 20/11 a 13/12 (2004/05). A produtividade foi alta, epiderme vermelha, polpa amarela, fruto redondo de tamanho médio a grande. CULTIVAR DE AMEIXEIRA REUBENNEL A planta é vigorosa, semi-aberta, muito produtiva. É suscetível à bacteriose. O fruto é de tamanho médio a grande. A epiderme é amarela-esverdeada com vermelho. A polpa é amarela. Cultivar de baixa exigência em frio. O período de floração, em Veranópolis, nas safras de 2000/01 a 2004/05 foi de 17/08 a 06/09 (2000/01), 10/08 a 28/08 (2001/02), 24/08 a 30/08 (2002/03), 02/09 a 24/09 (2003/04) e de 23/07 a 30/08 (2004/05). Já o período de colheita dessa cultivar, em Veranópolis, no período de 2000/01 a 2004/05 foi de 28/12 a 10/01 (2000/01), 18/12 a 28/12 (2001/02), 20/12 a 31/12 (2002/03), 28/12 a 08/01 (2003/04) e de 20/12 a 02/01 (2004/05). A produtividade foi alta, epiderme amarela-esverdeada com vermelho, polpa amarela, fruto redondo-cônico de tamanho médio a grande. CULTIVAR DE AMEIXEIRA SANTA RITA A planta é vigorosa, de hábito de crescimento ereto, muito produtiva e levemente suscetível à bacteriose. O fruto é de tamanho pequeno, com epiderme vermelha e polpa amarela com manchas vermelhas, quando bem maduras. Cultivar de média exigência em frio. O período de floração, em Veranópolis, nas safras de 2000/01 a 2004/05 foi de 06/09 a 30/09 (2000/01), 09/09 a 30/09 (2001/02), 31/08 a 28/09 (2002/03), 27/08 a 27/09 (2003/04) e de 01/09 a 28/09 (2004/05). Já o período de colheita dessa cultivar, em Veranópolis, no período de 2000/01 a 2004/05 foi de 28/01 a 17/02 (2000/01), 18/02 a 14/03 (2001/02), 27/01 a 13/02 (2002/03), 25/01 a 15/02 (2003/04) e de 29/01 a 23/02 (2004/05). A produtividade foi alta, epiderme vermelha, polpa amarela, fruto redondo de tamanho pequeno. CULTIVAR DE AMEIXEIRA SANTA ROSA A planta apresenta vigor médio e hábito de crescimento ereto. É suscetível à bacteriose. Produz frutos de tamanho médio e muito atrativos. A epiderme é vermelha-escura, a polpa amarela-rosada e bastante aromática. Cultivar de média exigência em frio. O período de floração, em Veranópolis, nas safras de 2000/01 a 2004/05 foi de 30/08 a 20/09 (2000/01), 05/09 a 22/09 (2001/02), 27/08 a 24/09 (2002/03), 20/08 a 10/09 (2003/04) e de 28/08 a 18/09 (2004/05). Já o período de colheita dessa cultivar, em Veranópolis, no período de 2000/01 a 2004/05 foi de 09/12 a 27/12 (2000/01), 16/12 a 04/01 (2001/02), 14/12 a 28/12 (2002/03), 30/11 a 16/12 (2003/04) e de 14/12 a 20/12 (2004/05). A produtividade foi de média a alta, epiderme rosa, polpa rosa, fruto redondo de tamanho médio.bitstream/item/101150/1/Maria-do-Carmo.pd

Usability Testing – An Aphasia Perspective

This paper reports the experience of participating in usability testing from the perspective of a person with aphasia. We briefly report adaptations to classic usability testing to enable the participation of people with aphasia. These included the use of short, direct tasks and physical artefacts such as picture cards. Authors of the paper include Ian, a user with aphasia who participated in adapted usability testing and Abi, a speech and language therapist researcher who facilitated sessions. Ian reports that these methods allowed him, as a person with aphasia, to engage with the usability testing process. We argue that such adaptations are essential in order to develop technologies which will be accessible to people with aphasia. This collaborative report provides a case for both how and why these adaptations can be made

Masses of the components of SB2 binaries observed with Gaia. II. Masses derived from PIONIER interferometric observations for Gaia validation

In anticipation of the Gaia astrometric mission, a sample of spectroscopic binaries is being observed since 2010 with the Sophie spectrograph at the Haute--Provence Observatory. Our aim is to derive the orbital elements of double-lined spectroscopic binaries (SB2s) with an accuracy sufficient to finally obtain the masses of the components with relative errors as small as 1 % when combined with Gaia astrometric measurements. In order to validate the masses derived from Gaia, interferometric observations are obtained for three SB2s in our sample with F-K components: HIP 14157, HIP 20601 and HIP 117186. The masses of the six stellar components are derived. Due to its edge-on orientation, HIP 14157 is probably an eclipsing binary. We note that almost all the derived masses are a few percent larger than the expectations from the standard spectral-type-mass calibration and mass-luminosity relation. Our calculation also leads to accurate parallaxes for the three binaries, and the Hipparcos parallaxes are confirmed.Comment: 10 pages, 3 figures, accepted by MNRA