Comparison of force and tactile feedback for grasp force control in telemanipulation

The comparative efficacy of using direct force feedback or a simple vibrotactile display to convey changes in the intensity of remote grasp force relayed from a robotic end effector is examined. The findings show that a simple vibrotactile cue, in the absence of direct force feedback, is effective in signaling abrupt changes in remote grasp force regardless of magnitude, and when changes in force are not too slow or protracted in nature (i.e., ramp time less than 2 s). In cases where the operator must dynamically tract and respond to slow but large variations in grasp force, the comparatively crude vibrotactile display would prove helpful; but would not be as effective as that of a direct contact force display. Immediate applications and utility of current generation and near-term prototype tactile displays are discussed

Strong spin-lattice coupling in multiferroic HoMnO3_{3}: Thermal expansion anomalies and pressure effect

Evidence for a strong spin-lattice coupling in multiferroic HoMnO_3 is derived from thermal expansion measurements along a- and c-axis. The magnetoelastic effect results in sizable anomalies of the thermal expansivities at the antiferromagnetic (T_N) and the spin rotation (T_{SR}) transition temperatures as well as in a negative c-axis expansivity below room temperature. The coupling between magnetic orders and dielectric properties below T_N is explained by the lattice strain induced by the magnetoelastic effect. At T_{SR} various physical quantities show discontinuities that are thermodynamically consistent with a first order phase transition

Vietnamska konfucijanska diplomatska tradicija ter dopisovanje med zadnjimi predkolonialnimi odposlanci vladavine Nguyễn in Li Hongzhangom

The Vietnamese envoys’ records during their diplomatic journeys to Beijing, especially poems and prose, have attracted increasing academic attention, from both international and local scholars. Some studies have comprehensively examined the Vietnamese envoys’ routes when visiting China, literary works, diplomatic strategies, and Confucian beliefs, such as the Taiwanese scholar Chen Yiyuan’s (陳益源) journal paper, which specifically problematizes the absence of filial expression related to the envoys’ journey in Xiaogan (孝感), Hubei Province. The systematic works of Liam C. Kelley and Peng Qian (彭茜) chiefly delineate the harmonious and normal communication based upon the long-developed cultural congruity between Vietnam and China. Their studies and other relevant research show the sophisticated impact of Chinese Confucianism on the Vietnamese envoys. However, there is so far insufficient investigation into the official representatives’ transformation and violation of Confucian manners and thoughts at specific historical moments. Hence, this paper intends to specify the practices of Confucian discourses in the final negotiation between the states of the Nguyễn and the Qing in 1883, both of which encountered the military threat from France and other Western countries. Our findings suggest that although those last envoys, including Phạm Thận Duật and Nguyễn Thuật, utilised a Sinocentric and Confucian manner to bargain with the Chinese for military aid, overall the Nguyễn adopted a Machiavellian approach instead. This means there was a division between political utility and ritual ethics, and the Vietnamese envoys, as pragmatic politicians, prioritized national security while discussing military aid in terms of Confucian rhetoric and values.Mednarodna in domača akademska skupnost čedalje večjo pozornost posvečata zapisom vietnamskih odposlancev, še posebej poeziji in prozi, ki so nastajali med njihovimi diplomatskimi potovanji v Peking. Avtorji so se v posameznih študijah osredotočili na poti, po katerih so potovali vietnamski odposlanci po kitajskem ozemlju, različna literarna dela, diplomatske strategije in konfucijanske ideje. Te še posebej izpostavi tajvanski učenjak Chen Yiyuan (陳益源), ki v svoji razpravi problematizira odsotnost poslušnosti in spoštovanja starejših na potovanju odposlancev v Xiaogan (孝感) v provinci Hubei. Liam C. Kelley in Peng Qiang (彭茜) sistematično prikažeta običajno harmonično komunikacijo, temelječo na kulturni skladnosti med Vietnamom in Kitajsko, ki se je oblikovala v daljšem zgodovinskem obdobju. Tovrstne študije sicer podrobno prikažejo sofisticiran vpliv kitajskega konfucianizma na vietnamske odposlance, a hkrati je še vedno premalo raziskav o uradnih predstavnikih in njihovih transformacijah ter kršenju konfucijanskih načel in idej v specifičnih zgodovinskih trenutkih. Članek zato poskuša prikazati prakse konfucijanskega diskurza v zadnjih pogajanjih med vladavino Nguyễn in dinastijo Qing leta 1883, ko sta se obe državi soočali z vojaškimi grožnjami Francije in drugih zahodnih dežel. Kljub temu da so zadnji odposlanci, kot na primer Phạm Thận Duật in Nguyễn Thuật, sinocentrična in konfucijanska načela uporabili kot metodo za uspešno pogajanje s kitajsko stranjo za vojaško pomoč, je Nguyễn namesto tega raje prevzel machiavellistični pristop. To kaže na razcep med politično koristjo in ritualno etiko, pri čemer so vietnamski odposlanci kot pragmatični politiki v kontekstu konfucijanske retorike in vrednot pri pogajanjih o vojaški pomoči prednostno obravnavali nacionalno varnost

Low temperature dielectric anomalies in HoMnO_3: The complex phase diagram

The dielectric constant of multiferroic hexagonal HoMnO_3 exhibits an unprecedented diversity of anomalies at low temperatures (1.8 K< T <10 K) and under external magnetic fields related to magnetic phase transitions in the coupled system of Ho moments, Mn spins, and ferroelectric polarization. The derived phase diagram is far more complex than previously assumed including reentrant phases, phase transitions with distinct thermal and field hysteresis, as well as several multicritical points. Magnetoelastic interactions introduce lattice anomalies at the magnetic phase transitions. The re-evaluation of the T-H phase diagram of HoMnO_3 is demanded.Comment: 12 pages, 3 figure

Pressure-Temperature Phase Diagram of Multiferroic Ni3V2O8Ni_3V_2O_8

The pressure-temperature phase diagram of multiferroic $Ni_3V_2O_8$ is investigated for hydrostatic pressures up to 2 GPa. The stability range of the ferroelectric phase associated with the incommensurate helical spin order is reduced by pressure and ferroelectricity is completely suppressed at the critical pressure of 1.64 GPa at 6.2 K. Thermal expansion measurements at ambient pressure show strong step-like anomalies of the lattice parameters associated with the lock-in transition into the commensurate paraelectric phase. The expansion anomalies are highly anisotropic, the related volume change is consistent with the high-pressure phase diagram

Marginally Trapped Surfaces in the Nonsymmetric Gravitational Theory

We consider a simple, physical approach to the problem of marginally trapped surfaces in the Nonsymmetric Gravitational Theory (NGT). We apply this approach to a particular spherically symmetric, Wyman sector gravitational field, consisting of a pulse in the antisymmetric field variable. We demonstrate that marginally trapped surfaces do exist for this choice of initial data.Comment: REVTeX 3.0 with epsf macros and AMS symbols, 3 pages, 1 figur

Coupling of Magnetic Order, Ferroelectricity, and Lattice Strain in Multiferroic Rare Earth Manganites

Multiferroic rare earth manganites attracted recent attention because of the coexistence of different types of magnetic and ferroelectric orders resulting in complex phase diagrams and a wealth of physical phenomena. The coupling and mutual interference of the different orders and the large magnetoelectric effect observed in several compounds are of fundamental interest and bear the potential for future applications in which the dielectric (magnetic) properties can be modified by the onset of a magnetic (dielectric) transition or the application of a magnetic (electric) field. The physical mechanisms of the magnetoelectric effect and the origin of ferroelectric order at magnetic transitions have yet to be explored. We discuss multiferroic phenomena in the hexagonal HoMnO3 and show that the strong magneto-dielectric coupling is intimately related to the lattice strain induced by unusually large spin-phonon correlations.Comment: Proceedings of the ACERS Annual Meeting, April 200

The Associations between Near Visual Activity and Incident Myopia in Children: A Nationwide 4-Year Follow-up Study

OBJECTIVE: This nationwide population-based study aimed to examine the prospective association between near visual activities and incident myopia in Taiwanese children 7 to 12 years old over a 4-year follow-up period. DESIGN: Prospective cohort design. PARTICIPANTS: There were 1958 children aged 7 to 12 years from the Taiwan 2009 National Health Interview Survey who were linked to the 2009 through 2013 claims data from the National Health Insurance system. METHODS: Multivariable Cox proportional hazard models were used to estimate the associations between 3 types of near visual activities in sedentary posture, namely reading (< 0.5, 0.5-0.9, ≥1.0 hours per day [h/d]), use of computer, Internet, and games (<0.5, 0.5-0.9, ≥1.0 h/d), and "cram school" attendance (<0.5, 0.5-1.9, ≥2.0 h/d), and incident myopia. MAIN OUTCOME MEASURES: Prevalent myopia was defined as those who had ≥2 ambulatory care claims (International Classification of Diseases code 367.1) in 2008-2009. Incident myopia was defined by those who had at least 2 ambulatory care claims (International Classification of Diseases code 367.1) during the 4-year follow-up period (2010-2013) after excluding prevalent cases. RESULTS: Overall, 26.8% of children had myopia at baseline, and 27.7% of those without myopia at baseline developed incident myopia between 2010 and 2013. On average, they spent 0.68±0.86 h/d on computer/Internet use, 0.63±0.67 h/d on reading, and 2.78±3.53 h/d on cram school. The results showed that children attending cram schools ≥2 h/d (hazard ratio, 1.31; 95% confidence interval, 1.03-1.68) had a higher risk of incident myopia. The effects of these activities remained similar in sensitivity analyses. CONCLUSIONS: Cram school attendance for ≥2 h/d may increase the risk of children's incident myopia. This effect may be due to increased near visual activity or reduced time outdoors