The Alpha Magnetic Spectrometer (AMS) on the international space station: Part II — Results from the first seven years

The Alpha Magnetic Spectrometer (AMS) is a precision particle physics detector on the International Space Station (ISS) conducting a unique, long-duration mission of fundamental physics research in space. The physics objectives include the precise studies of the origin of dark matter, antimatter, and cosmic rays as well as the exploration of new phenomena. Following a 16-year period of construction and testing, and a precursor flight on the Space Shuttle, AMS was installed on the ISS on May 19, 2011. In this report we present results based on 120 billion charged cosmic ray events up to multi-TeV energies. This includes the fluxes of positrons, electrons, antiprotons, protons, and nuclei. These results provide unexpected information, which cannot be explained by the current theoretical models. The accuracy and characteristics of the data, simultaneously from many different types of cosmic rays, provide unique input to the understanding of origins, acceleration, and propagation of cosmic rays.</p

Molecular engineering of cocktail co-sensitization for efficient panchromatic porphyrin-sensitized solar cells

Co-sensitization of two or more dyes with complementary absorption spectra on a semiconductor film is an effective approach to enhance the performance of a dye-sensitized solar cell (DSSC). Porphyrin sensitizer YD2-oC8 showed outstanding photovoltaic performance co-sensitized with an organic dye to cover the entire visible spectral region, 400–700 nm. To promote the light-harvesting capability beyond 700 nm, a porphyrin dimer (YDD6) was synthesized for a co-sensitized system. We report a systematic approach for engineering of molecular co-sensitization of TiO2 films in a cocktail solution containing YD2-oC8, an organic dye (CD4) and YDD6 in a specific molar ratio to optimize the photovoltaic performance of the device. The resulting device showed panchromatic spectral features in the IPCE action spectrum in the region 400–700 nm attaining efficiencies of 75–80%; the spectrum is extended to the near-IR region attaining 40–45% in 700–800 nm region, giving JSC/mA cm 2 ¼ 19.28, VOC/mV ¼ 753, FF ¼ 0.719, and h ¼ 10.4% under standard AM 1.5 G one-sun irradiation. This performance is superior to what is obtained from the individual single-dye devices and the two-dye co-sensitized systems. The shifts of TiO2 potential upon dye uptake and the kinetics of charge recombination were examined through measurements of the charge extraction (CE) and intensity-modulated photovoltage spectroscopy (IMVS), respectively. Five co-sensitized systems were investigated to demonstrate that suppression of dye aggregation of YDD6 in the co-sensitized film is a key factor to further improve the device performance

Electrochemical regulation of microbial growth on disposable screen printed carbon electrodes

Herein we report an effective method to enhance microbial immobilization on screen-printed carbon electrode (SPCE) surface by electrochemical regulation of redox potential. This technique could deliver a prospective electrode for microbial biofuel cell and other applications. A phototrophic purple nonsulfur bacterium Rhodopseudomonas palustris CGA009 was selected as a model organism to examine the proposed approach. Scanning the electrode between −0.7 to 0.3 V (vs. Ag/AgCl) at 70 mV/s for 50 cycles (∼24 min), placed in the growth medium with bacteria, significantly increased microbial adhesion when compared to SPCE without electrochemical stimulation. The electron-transfer effect between the adsorbed microorganism and electrode surface was further studied by AC impedance spectroscopy to confirm the accelerated microbial immobilization. Stable photosynthetic electron transport chain from immobilized bacteria through SPCE was achieved