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In last years,consumers pay more attention to natural and body-friendly pigments. There is a great tendency to promote and popularize natural dyes instead of synthetics. But instability of these natural pigments has many negative impacts on application. However,melanoidins,high molecular weight brown nitrogenous polymers formed at the end of the Maillard reaction,are increasingly studied by scholars ascribe to its enormous biological activity. They are normally formed during heat processing of foods. This brown-colored compounds may be a natural pigment due to its desirable dark brown and biological activity.what’s more,its ability is superior to other natural pigments. On the other hand,this compounds’ isolation and purification are the key step for further use and biological maintenance in various kinds of industries. However,the selection of methods is mainly dependent on their structure. It is necessary to seek out some effective modification or advanced technologies to update and even take place of the traditional methods, among which a large quantity of ways about extraction is time-consuming. Hence,this review summarizes extraction methods of melanoidins,exploring the recent literature regarding the feasibility of emerging extraction methods and as a new potential natural pigment.

In this study, a novel polyethyleneimine (PEI) modified MOF-derived carbon adsorbent (PEI@MDC) was proposed, which exhibited significant adsorption capacity for Congo Red (CR) in aqueous solutions. FT-IR and XPS results showed that PEI was successfully grafted onto MDC, increasing the content of amine groups on the surface of MDC. The adsorption process conformed to the Langmuir isotherm adsorption model and pseudo-second-order kinetic equation, indicating that the adsorption of CR on PEI@MDC was covered by a single layer, and the adsorption process was controlled by chemical processes. According to the Langmuir model, the maximum adsorption capacity at 30 °C was 1723.86 mg g

GOST, known as GOST-28147-89, was standardized as the Russian encryption standard in 1989. It is a lightweight-friendly cipher and suitable for the resource-constrained environments. However, due to the simplicity of GOST’s key schedule, it encountered reflection attack and fixed point attack. In order to resist such attacks, the designers of GOST proposed a modification of GOST, namely, 2-GOST. This new version changes the order of subkeys in the key schedule and uses concrete S-boxes in round function. But regarding single-key attacks on full-round 2-GOST, Ashur et al. proposed a reflection attack with data of 2 32 on a weak-key class of size 2 224 , as well as the fixed point attack and impossible reflection attack with data of 2 64 for all possible keys. Note that the attacks applicable for all possible keys need the entire plaintext space. In other words, these are codebook attacks. In this paper, we propose single-key attacks on 2-GOST with only about 2 32 data instead of codebook. Firstly, we apply 2-dimensional meet-in-the-middle attack combined with splice-cut technique on full-round 2-GOST. This attack is applicable for all possible keys, and its data complexity reduces from previous 2 64 to 2 32 . Besides that, we apply splice-cut meet-in-the-middle attack on 31-round 2-GOST with only data of 2 32 . In this attack, we only need 8 bytes of memory, which is negligible.

In this paper, a four-fed metallic antenna with two feeding networks, which has switchable dual-circular-polarization performance in an ultra wide frequency band, is presented. The antenna is an improvement of a slot patch antenna, combining broadband feeding structure and metal ground structure for parasitical radiation. The feeding network is composed of two three-ports 180°phase-shifters and a low profile 3dB 90°-hybrid coupler chip. This antenna achieves circular polarization switching by hybridizing two 180°phase-shifters with 90° phase difference between their inputs. The antenna is designed and optimized to cover X band(8-12GHz).

A modified wideband and wide-beam Archimedean spiral antenna, with the characteristics of circularly polarization, four arms and mode-2 operation, is presented in this paper. The antenna features a modified cup-shaped cavity and a dielectric substrate with twelve metal patches printed on it. The simulated results show that the voltage standing wave ratio (VSWR) is better than 2 over the operating band of 8∼12GHz. The beamwidth of the modified spiral antenna is greatly broadened compared with the conventional antenna. Over the whole operating frequency band, the beamwidth of the modified Archimedean spiral antenna is about ± (15°∼75°).