[en] We explicitly evaluate the one-loop amplitude of the string theory on the T²²/G manifold and show that the theory is finite at the one-loop level. The twisted sectors play a crucial role in the proof of the modular-group invariance

[en] The energy loss, produced by shielding effect of steel cage outside the source tube, is quite considerable. With PENELOPE software package, MC results have been obtained based on the simulation of different source conformations. The result illustrates that the naked source tubes can improve the utilization ratio of the cobalt facilities. It demonstrates the applied value of the naked source tube in engineering. (authors)

[en] The shielding effect of the steel cylinder and steel cage outside a ⁶⁰Co source pencil will be discussed here. With PENELOPE software package, M-C results have been obtained based on different geometry conformations: 2-D and different 3-D source configurations. The result shows that characteristics of gamma ray and depth dose distributions have been changed a lot from different geometry conformations. And some utilizable information would be offered to cobalt source factory. (authors)

[en] Paired ionization chambers used for the dosimetry of mixed gamma-neutron field in reactor, consist of a tissue-equivalent chamber which responds to both neutron and gamma radiation, and a nonhydrogenous chamber which is relatively insensitive to neutron. In this work, the gamma radiation energy response and response factor of tissue-equivalent chambers under different conditions were calculated by MCNP code for the development of paired chambers. The calculated result is in accordance well with the result in references. (authors)

[en] Monte Carlo method has been applied extensively in radiation transport studies. It can also be of great help for designing or upgrading a ⁶⁰Co γ-ray irradiator by providing theoretical estimations of dosimetry distribution in the product containers and radiation protection effects of the shielding. In this paper, Monte Carlo simulations were performed using PENELOPE transport code for dosimetry distribution in product containers of a new ⁶⁰Co γ-ray irradiator, which has a 228 cm (w) x 200 cm (h) source plaque with 24 source pencils (12.5 kCi/pencil) and 36 irradiation positions in six paths for over head carriers of 75 cm (l) x 62 cm (w) x 190 cm (h). A carrier that has completed the first three paths is turned 180 degree to ensure uniform irradiation of the two sides. Fig.1 is dosimetry simulation results with empty carriers (with air), while Fig.2 is the results with carriers loaded with products in average density of 1 g/cm³ (with water). A carrier was divided into 120 voxels for the MC simulation, and dosimetry uniformity of the carrier is 1.28 . (authors)

[en] Recently, some researchers have pointed out that the threats of ionic liquids (ILs) to aquatic environment cannot be ignored. Thus, this study investigated the potential toxicity of 1-dodecyl-3-methylimidazolium tetrafluoroborate ([C₁₂mim]BF₄) on a marine diatom Phaeodactylum tricornutum at population, biochemical and physiological levels using 96 h growth tests with a batch-culture system. Results showed that [C₁₂mim]BF₄ was very stable in aquatic environment during 96 h of exposure. The growth of P. tricornutum was significantly inhibited by [C₁₂mim]BF₄ with 24, 48, 72 and 96 h EC₅₀ values of 0.63, 0.61, 0.68 and 0.72 mg L⁻¹, respectively. Although there were no significant differences between the controls and treatments with 0.1 and 0.5 mg L⁻¹ [C₁₂mim]BF₄, the effective quantum yields (Φ_PSII) of the diatom in 1, 2.5, 5 and 10 mg L⁻¹ [C₁₂mim]BF₄ treatments were 61.48, 17.04, 2.96 and 0.74% of that in the controls at 96 h of exposure, respectively. Chl a content of the diatom was decreased by 34.86, 47.79, 49.81, 59.21, 79.82 and 86.98% compared with that of the controls at 96 h of exposure in 0.1, 0.5, 1, 2.5, 5 and 10 mg L⁻¹ [C₁₂mim]BF₄ treatments, respectively. Relative to the controls, soluble sugar content, reactive oxygen species (ROS) level, malondialdehyde (MDA) content, superoxide dismutase (SOD) and peroxidase (POD) activities of the diatom increased with increasing [C₁₂mim]BF₄ concentrations at 96 h of exposure, and reached their maxima (1.46 μg 10⁶ cell⁻¹, 7.48 FU 10⁷ cell⁻¹, 3.35 nmol 10⁸ cell⁻¹, 33.41 and 7.23 U mg⁻¹ proteins, respectively) in 5 mg L⁻¹ [C₁₂mim]BF₄ treatments. While the maximum soluble protein content (1.56 μg 10⁶ cell⁻¹) of the diatom was obtained in 0.5 mg L⁻¹ [C₁₂mim]BF₄ treatments, and then decreased with increasing [C₁₂mim]BF₄ concentrations from 0.5 to 10 mg L⁻¹. These findings provide strong evidence for the potential toxicity of ILs to marine diatoms. - Highlights: • [C₁₂mim]BF₄ was very stable in aquatic environment during 96 h of exposure. • Photosynthetic activity of P. tricornutum was inhibited by [C₁₂mim]BF₄. • Physiological effects of [C₁₂mim]BF₄ on the diatom were caused by ROS generation. • SOD and POD were considered as stimulatory responses of the diatom to [C₁₂mim]BF₄.

[en] Experiments involving liquid-waste powdering, direct granulation from powdered salts as well as the performance of calcium hydroxide formula was carried out to investigate the treatment technology of simulated boron-containing liquid waste. The results indicate that powdered salts can be made into pellets, but their water immersion performance can not meet the requirement. At the parameters (Ca/B molar ratio is 0.5, reacting temperature is 75 ℃, and reacting time is 60 min) being recommended after test, waste liquid can be successfully powdered after pretreatment by adding calcium hydroxide, and water immersion resistance of pellets meet the requirement of solidification after the powdered salts being made into pellets. (authors)

[en] It is very important to have a good understanding of the biological effects of nanoparticles (NPs) on marine diatoms. In this study, the physiological and biochemical responses of a marine diatom Phaeodactylum tricornutum to titanium dioxide NPs (nano-TiO₂) and cerium oxide NPs (nano-CeO₂) were compared and evaluated using 96 h growth tests in a batch-culture system. At 96 h of exposure, the growth inhibition rate (IR, %) of P. tricornutum increased from 5.46 to 27.31% with increasing nano-TiO₂ concentrations from 2.5 to 40 mg L⁻¹. The maximum IR of 49.59% occurred in 40 mg L⁻¹ nano-TiO₂ treatments at 48 h of exposure. Growth of the diatom was increased in low nano-CeO₂ treatments (≤ 5 mg L⁻¹), but was inhibited in high nano-CeO₂ treatments (≥ 10 mg L⁻¹). Large aggregates of NPs were attached to the cells of P. tricornutum in 20 and 40 mg L⁻¹ nano-TiO₂ and nano-CeO₂ treatments. In addition, the effective quantum yields (Φ_PSII) of P. tricornutum in 40 mg L⁻¹ nano-TiO₂ and nano-CeO₂ treatments were 83.33 and 71.13% of that in the controls at 96 h of exposure, respectively. Compared with that of the controls at 96 h of exposure, chlorophyll a content, soluble sugar content, malondialdehyde (MDA) content, SOD and POD activities of P. tricornutum in 40 mg L⁻¹ nano-TiO₂ and nano-CeO₂ treatments increased by 57.56, 142.97, 373.25, 698.76, 204.85% and 21.43, 89.41, 194.97, 340.05, 502.86%, while soluble protein content decreased by 70.38 and 28.64%, respectively. These findings will be helpful to understand the effect mechanisms of NPs on marine organisms. - Highlights: • Photosynthetic activity of P. tricornutum was inhibited by nano-TiO₂ and nano-CeO₂. • Soluble sugar may serve as an osmotic agent to improve resistance of the diatom. • Physiological effects of both NPs on the diatom were caused by ROS generation. • SOD and POD were considered as a stimulatory response of the diatom to both NPs.

[en] Graphical abstract: -- Highlights: •The molecularly imprinted polymer capped core–shell AuNPs (MIP-ir-AuNPs) were fabricated as a specific functional SERS substrate. •MIP-ir-AuNPs could be utilized in rapid and selective detection of BPA. •MIP-ir-AuNPs displayed good capability for determination of BPA in real samples. -- Abstract: Surface-imprinted core–shell Au nanoparticles (AuNPs) were explored for the highly selective detection of bisphenol A (BPA) by surface-enhanced Raman scattering (SERS). A triethoxysilane-template complex (BPA-Si) was synthesized and then utilized to fabricate a molecularly imprinted polymer (MIP) layer on the AuNPs via a sol–gel process. The imprinted BPA molecules were removed by a simple thermal treatment to generated the imprint-removed material, MIP-ir-AuNPs, with the desired recognition sites that could selectively rebind the BPA molecules. The morphological and polymeric characteristics of MIP-ir-AuNPs were investigated by transmission electron microscopy and Fourier-transform infrared spectroscopy. The results demonstrated that the MIP-ir-AuNPs were fabricated with a 2 nm MIP shell layer within which abundant amine groups were generated. The rebinding kinetics study showed that the MIP-ir-AuNPs could reach the equilibrium adsorption for BPA within 10 min owning to the advantage of ultrathin core–shell nanostructure. Moreover, a linear relationship between SERS intensity and the concentration of BPA on the MIP-ir-AuNPs was observed in the range of 0.5–22.8 mg L⁻¹, with a detection limit of 0.12 mg L⁻¹ (blank ± 3 × s.d.). When applied to SERS detection, the developed surface-imprinted core–shell MIP-ir-AuNPs could recognize BPA and prevent interference from the structural analogues such as hexafluorobisphenol A (BPAF) and diethylstilbestrol (DES). These results revealed that the proposed method displayed significant potential utility in rapid and selective detection of BPA in real samples

[en] Highlights: • A tube-fin cool storage heat exchanger (CSHE) is proposed for use in thermal control systems. • A CSHE can extend the thermal control time by 114.8% and can be recycled. • The thermal control performance of 0% graphene mass fraction in PCM is greater than that of 5%. -- Abstract: This study sought to examine the applications of tube-fin cool storage heat exchangers (CSHEs) in thermal control systems. To achieve the thermal control in electronic devices, the CSHE is filled with No. 28 paraffin phase change material (PCM) which is solidified by cooling water, ensuring the sustainable use of the CSHE. The graphene powder is blended with paraffin as a heat conduction enhancer. The thermal control performance of the CSHE during the melting–solidifying process is investigated experimentally and numerically. A series of experiments are carried out under various heat fluxes, graphene mass fractions, and cooling water flow rates. In addition, a three-dimensional mathematical model based on enthalpy–porosity and melting–solidifying models is established to investigate the distributions of the solid–liquid phase and temperature. Our results indicated that the thermal control time is increased by 114.8% at a heating power of 800 W. At the maximum heat flux of 1000 W, the heat control time of the CSHE under the 5%, 2.5%, and 0% components is 25, 29, and 40 min, respectively. During the solidification process, the addition of graphene powder can significantly increase the solidification rate.