Spin-thermoelectric effects in a quantum dot hybrid system with magnetic insulator.

We investigate spin thermoelectric properties of a hybrid system consisting of a single-level quantum dot attached to magnetic insulator and metal electrodes. Magnetic insulator is assumed to be of ferromagnetic type and is a source of magnons, whereas metallic lead is reservoir of electrons. The temperature gradient set between the magnetic insulator and metallic electrodes induces the spin current flowing through the system.

Ultra-fast optical ranging using quantum-dash mode-locked laser diodes.

Laser-based light detection and ranging (LiDAR) is key to many applications in science and industry. For many use cases, compactness and power efficiency are key, especially in high-volume applications such as industrial sensing, navigation of autonomous objects, or digitization of 3D scenes using hand-held devices. In this context, comb-based ranging systems are of particular interest, combining high accuracy with high measurement speed.

Coherent WDM transmission using quantum-dash mode-locked laser diodes as multi-wavelength source and local oscillator.

Quantum-dash (QD) mode-locked laser diodes (MLLD) lend themselves as chip-scale frequency comb generators for highly scalable wavelength-division multiplexing (WDM) links in future data-center, campus-area, or metropolitan networks. Driven by a simple DC current, the devices generate flat broadband frequency combs, containing tens of equidistant optical tones with line spacings of tens of GHz. Here we show that QD-MLLDs can not only be used as multi-wavelength light sources at a WDM transmitter, but also as multi-wavelength local oscillators (LO) for parallel coherent reception.

Comb-based WDM transmission at 10 Tbit/s using a DC-driven quantum-dash mode-locked laser diode.

Chip-scale frequency comb generators have the potential to become key building blocks of compact wavelength-division multiplexing (WDM) transceivers in future metropolitan or campus-area networks. Among the various comb generator concepts, quantum-dash (QD) mode-locked laser diodes (MLLD) stand out as a particularly promising option, combining small footprint with simple operation by a DC current and offering flat broadband comb spectra. However, the data transmission performance achieved with QD-MLLD was so far limited by strong phase noise of the individual comb tones, restricting experiments to rather simple modulation formats such as quadrature phase shift keying (QPSK) or requiring hardware-based compensation schemes.

Cross-correlations in a quantum dot Cooper pair splitter with ferromagnetic leads.

We investigate Andreev transport through a quantum dot attached to two external ferromagnetic leads and one superconducting electrode. The transport properties of the system are studied by means of the real-time diagrammatic technique in the sequential tunneling regime. To distinguish various contributions to Andreev current we calculate the current cross-correlations, i.

Ultrafast optical ranging using microresonator soliton frequency combs.

Light detection and ranging is widely used in science and industry. Over the past decade, optical frequency combs were shown to offer advantages in optical ranging, enabling fast distance acquisition with high accuracy. Driven by emerging high-volume applications such as industrial sensing, drone navigation, or autonomous driving, there is now a growing demand for compact ranging systems.

Microresonator-based solitons for massively parallel coherent optical communications.

Solitons are waveforms that preserve their shape while propagating, as a result of a balance of dispersion and nonlinearity. Soliton-based data transmission schemes were investigated in the 1980s and showed promise as a way of overcoming the limitations imposed by dispersion of optical fibres. However, these approaches were later abandoned in favour of wavelength-division multiplexing schemes, which are easier to implement and offer improved scalability to higher data rates.

Current cross-correlations in double quantum dot based Cooper pair splitters with ferromagnetic leads.

We investigate the current cross-correlations in a double quantum dot based Cooper pair splitter coupled to one superconducting and two ferromagnetic electrodes. The analysis is performed by assuming a weak coupling between the double dot and ferromagnetic leads, while the coupling to the superconductor is arbitrary. Employing the perturbative real-time diagrammatic technique, we study the Andreev transport properties of the device, focusing on the Andreev current cross-correlations, for various parameters of the model, both in the linear and nonlinear response regimes.

Field Measurement-Based System Identification and Dynamic Response Prediction of a Unique MIT Building.

Tall buildings are ubiquitous in major cities and house the homes and workplaces of many individuals. However, relatively few studies have been carried out to study the dynamic characteristics of tall buildings based on field measurements. In this paper, the dynamic behavior of the Green Building, a unique 21-story tall structure located on the campus of the Massachusetts Institute of Technology (MIT, Cambridge, MA, USA), was characterized and modeled as a simplified lumped-mass beam model (SLMM), using data from a network of accelerometers.

Spin-dependent thermoelectric properties of a Kondo-correlated quantum dot with Rashba spin-orbit coupling.

Thermoelectric transport phenomena in a single-level quantum dot coupled to ferromagnetic leads are considered theoretically in the Kondo regime. The dot is described by the Anderson model with Rashba type spin-orbit interactions. The finite-U mean field slave boson technique is used to describe transport characteristics, such as the heat conductance, thermopower and thermoelectric efficiency (figure of merit).

The role of the indirect tunneling processes and asymmetry in couplings in orbital Kondo transport through double quantum dots.

A system of two quantum dots attached to external electrodes is considered theoretically in the orbital Kondo regime. In general, the double dot system is coupled via both Coulomb interaction and direct hopping. Moreover, the indirect hopping processes between the dots (through the leads) are also taken into account.

Kondo-Dicke resonances in electronic transport through double quantum dots.

Electronic transport through a system of two quantum dots coupled to external leads is considered theoretically. The dots are assumed to be in the Kondo regime, and the infinite-U mean-field slave-boson approach is used to obtain basic transport characteristics. Density of states and electron transmission probability in the Kondo regime are considered and calculated numerically.

Effect of radioprotectant WR 2721 on cyclic nucleotides, prostaglandins, and lysosomes.

Within 1 hr after ip injection of the radioprotectant WR 2721 into rats, splenic cGMP levels dropped and remained suppressed for 6 hr before returning to normal. However, if rats were exposed to ionizing radiation 30-40 min after WR 2721 treatment, they had higher cGMP levels at 3 hr postirradiation than the nonirradiated, drug-treated controls, but the cGMP content was still found to be lower than that of the irradiated nondrug-treated controls. Radiation exposure of animals pretreated with WR 2721 also resulted in higher liver and spleen levels of cAMP and additional elevations in spleen prostaglandin content, compared with irradiated controls at 3-6 hr after radiation treatment.

Effects of WR 2721 on cyclic nucleotide levels and lysosomal enzyme activities.

The radioprotectant WR 2721 administered intraperitoneally to rats at 30--40 min before exposure to 1000 rad of 60Co caused a reduction in spleen lysosomal enzyme activity and fluctuations in cyclic nucleotide levels. Liver and spleen cAMP levels from drug-treated animals were higher at 3--6 hr postirradiation whereas spleen cGMP levels were lower at 1--4 hr postirradiation than irradiated controls not given the radioprotectant. At 3 days after radiation exposure, spleen cyclic nucleotide levels and lysosomal enzyme activities in rats given WR 2721 were closer to the level of nonirradiated control rats than of irradiated rats receiving saline.

Prostaglandin levels and lysosomal enzyme activities in irradiated rats.

Whole-body irradiation of rats results in the release of hydrolases from lysosomes, an increase in lysosomal enzyme activities, and changes in the prostaglandin levels in spleen and liver tissues. A transient increase in the concentration of prostaglandins E and F and leakage of lysosomal hydrolases occurred in both spleen and liver tissues 3-6 hours after the animals were irradiated. Maximal values for hydrolase activities, prostaglandin E and F content, and release of lysosomal enzymes were found 4 days postirradiation in rat spleens whereas in the liver only slight increases were observed at this time period for prostaglandin F levels.

Method for screening urinary steroids by gas chromatography.

Numerous methods are available for measuring urinary steroids in evaluating endocrine dysfunctions. Measurements of these particular steroids, or groups of them, usually involve tedious isolation methods, corrections for interferences and losses of the steroid, and (or) expensive reagents. We show how gas-liquid chromatography provides a rapid, sensitive, and direct method for several steroid metabolites in urine.

Yeast mutants blocked in removing the methyl group of lanosterol at C-14. Separation of sterols by high-pressure liquid chromatography.

Sterols of a nystatin resistant mutant of the wild type parent of Saccharomyces cerevisiae were separated by a newly developed procedure involving high-pressure liquid chromatography and were identified. The mutant contained larger amounts of squalene and lanosterol (I) than the wild type, as well as 4,14-dimethylcholesta-8,24-dien-3beta-ol (II), 4,14-dimethylergosta-8,24(28)-dien-3beta-ol (III), and 14-methylergosta-8,24(28)-dien-3beta-ol (IV), which were not hitherto found in yeast. These results indicated a block in removal of the methyl group at C-14 of lanosterol.

Lactate dehydrogenase isoenzymes linked to beta-lipoproteins and immunoglobulin A.

A clinically asymptomatic individual had an abnormal electrophoretic pattern for lactate dehydrogenase, seven isoenzyme bands being present. This atypical pattern was a result of an interaction of lactate dehydrogenase with immunoglobulin A and beta-lipoprotein. Lactate dehydrogenase enzymes LD2 and LD3 were the isoenzymes responsible for the formation of the complexes.