Probing primordial gravitational waves: Ali CMB Polarization Telescope.

In this paper, we will give a general introduction to the Ali CMB Polarization Telescope (AliCPT) project, which is a Sino-US joint project led by the Institute of High Energy Physics and involves many different institutes in China. It is the first ground-based Cosmic Microwave Background (CMB) polarization experiment in China and an integral part of China's Gravitational-wave Program. The main scientific goal of the AliCPT project is to probe the primordial gravitational waves (PGWs) originating from the very early Universe. The AliCPT project includes two stages. The first stage, referred to as AliCPT-1, is to build a telescope in the Ali region of Tibet at an altitude of 5250 meters. Once completed, it will be the highest ground-based CMB observatory in the world and will open a new window for probing PGWs in the northern hemisphere. The AliCPT-1 telescope is designed to have about 7000 transition-edge sensor detectors at 95 GHz and 150 GHz. The second stage is to have a more sensitive telescope (AliCPT-2) with more than 20 000 detectors. Our simulations show that AliCPT will improve the current constraint on the tensor-to-scalar ratio r by one order of magnitude with three years' observation. Besides the PGWs, AliCPT will also enable a precise measurement of the CMB rotation angle and provide a precise test of the CPT symmetry. We show that three years' observation will improve the current limit by two orders of magnitude.

[Air humidity solubility assay].

Measurement of drug solubility is one of the key elements of compound characterization during the drug discovery and development process. A broad variety of solubility assay methods have been developed, including equilibrium method which requires analysis of the equilibrium composition and kinetic method which monitors the concentration of a compound dynamically at the time when a precipitate first appears or disappears in the solution. Despite the numerous experimental methods, precise drug solubility values are hard to obtain for time-consuming, sample size and manual work. In this article, we reported a new method, namely air humidity solubility assay, which measures the relative humidity of the air in equilibrium with the solution at a given temperature, and then calculates solubility from the relative humidity according to extended-non random two liquid (NRTL) model. NaCl was used as a model drug, and the solubility was measured at the temperature of 20-50 ℃. The results indicate that the solubility of NaCl determined with the new method is generally comparable to that determined by gravimetry that is reported in literature. The new method has a relative error of less than 2%. Although the accuracy is lower than that of gravimetry, air humidity solubility assay is more convenient, practical, operational and universal. This method provides a supplement to the existing methods.