SYNTHESIS AND AVERAGE SEQUENCE LENGTH DETERMINATION OF AROMATIC-ALIPHATIC COPOLYESTERS CONTAINING POLY(ALKYLENE OXALATE)UNITS

Two series of aromatic-aliphatic random copolyesters(PEBTOXS)with diverse diol ratios have been synthesized by direct melting polycondensation.Two kinds of diols(glycol(EG)and 1,4-butanediol(BD))are used in combination in order to adjust crystallization and tensile properties,and three kinds of diacids(dimethyl terephthalate(DMT),diethyl oxalate(DEOX),and sebacic acid(SA))are involved.~1H-NMR spectra quantify both composition and structure,and show that the final contents in copolyesters appropriate to the ...

Length matters:Scalable fast encrypted internet traffic service classification based on multiple protocol data unit length sequence with composite deep learning

As an essential function of encrypted Internet traffic analysis,encrypted traffic service classification can support both coarse-grained network service traffic management and security supervision.However,the traditional plaintext-based Deep Packet Inspection(DPI)method cannot be applied to such a classification.Moreover,machine learning-based existing methods encounter two problems during feature selection:complex feature overcost processing and Transport Layer Security(TLS)version discrepancy.In this paper,we consider differences between encryption network protocol stacks and propose a composite deep learning-based method in multiprotocol environments using a sliding multiple Protocol Data Unit(multiPDU)length sequence as features by fully utilizing the Markov property in a multiPDU length sequence and maintaining suitability with a TLS-1.3 environment.Control experiments show that both Length-Sensitive(LS)composite deep learning model using a capsule neural network and LS-long short time memory achieve satisfactory effectiveness in F1-score and performance.Owing to faster feature extraction,our method is suitable for actual network environments and superior to state-of-the-art methods.

Complete genome sequence analysis of two Citrus tatter leaf virus(CTLV) isolates from China

In order to understand molecular characterization of Citrus tatter leaf virus（CTLV） isolated from China,full-length cDNAs of CTLV-MTH and CTLV-XHC from Citrus reticulata and Citrus sinensis were cloned and sequenced based on whole-genome amplification by RT-PCR.The complete nucleotide sequences of CTLV-MTH and CTLV-XHC were determined to be 6497 nucleotides in length and shared 79.9-91.0%and 78.8-98.0%nucleotide sequence identity,respectively,with other Apple stem grooving virus（ASGV） or CTLV strains available in GenBank.Unexpectedly,CTLV-MTH showed the highest nucleotide sequence identity（91%） with an apple isolate of ASGV,followed by 86.5%with ASGV-HH and 85.7%with ASGV-CHN.Furthermore,CTLV-MTH and three ASGV strains were grouped to a separate cluster in the phylogenetic tree,suggesting it has a closer relationship to ASGV than to CTLV.Therefore,it can be concluded roughly that CTLV may be not a distinct strains of ASGV.We proposed that Citrus tatter leaf virus should be renamed Apple stem grooving virus.

Mapping of a New Gene Wbph6(t) Resistant to the Whitebacked Planthopper, Sogatella furcifera, in Rice

A rice population consisting of 90 TN1/Guiyigu F3 lines was employed to analyze the linkage between DNA markers and a new gene Wbph6(t) conferring resistance to whitebacked planthopper, Sogatella furcifera By using the mapping approach of bulked extremes and recessive class, Wbph6(t) was mapped onto the short arm of chromosome 11 with a genetic distance of 21.2 cM to SSLP marker RM167.

EFFECTS OF CHAIN MICROSTRUCTURE OF BUTADIENE-ISOPRENE COPOLYMERS ON THEIR GLASS TRANSITION AND CRYSTALLIZATION

A series ofbutadiene-isoprene copolymers （BIR） with various compositions were synthesized with a neodymiumbased catalyst system. The microstructure, composition and sequence of copolymers were characterized by FTIR and ^13C-NMR spectroscopy. The crystallization behavior of the BIR copolymers was investigated by DSC analysis. The results demonstrate that the content of cis-1,4 configuration in both butadiene （Bd） and isoprene （Ip） units are around 98% when Bd content in feed （fBd） covering the range from 55.7 mol% to 96.0 mol%. The reactivity ratios of Bd and Ip were determined to be 1.40 and 0.48 respectively. The random copolymers of Bd and Ip show only one glass transition temperature （Tg） from -107.4℃ to -80.5℃, which is dependent on the composition and fits nicely with Fox equation. The sequence distribution followed the first-order Markov statistical model. It is found that the copolymer chains with higher Bd content contain longer polybutadiene （PBd） segments, and the sequence length of PBd segments （NBd） exhibits great influence on the crystallization behavior of the copolymer. The copolymers with NBd ≥ 11.8 could crystallize at low temperatures （-71℃ to -43℃）. The crystallization temperature and enthalpy values decreased gradually with decreasing NBd. The copolymers with NBd ≤ 7.9 are amorphous even at very low temperatures （0℃ to -150℃） due to the short PBd segments.

Microstructure Characterization of Short-chain Branching Polyethylene with Differential Scanning Calorimetry and Successive Self-nucleation/Annealing Thermal Fractionation

A series of the copolymers of ethylene with 1-hexene （M1-M9） synthesized by metallocene catalyst Et[Ind]2ZrC1JMAO was studied by differential scanning calorimetry and successive self-nucleation and annealing （SSA） thermal fractionation. The distribution of methylene sequence length （MSL） in the different copolymers was determined using the SSA method. The comonomer contents of samples M4 and M5 are 2.04 mol% and 2.78 mol%, respectively. Both M4 and M5 have low comonomer content and their MSL distribution profiles exhibit a monotonous increase trend with their MSL. The longest MSL of M5 is 167, and its corresponding molar percent is 43.95%, which is higher than that of M4. Moreover, the melting temperature （Tm） of M5 is also higher than that of M4. The comonomer contents of samples M7, M8, and M9 are 8.73 mol%, 14.18 mol% and 15.05 mol%, respectively. M7, M8, and M9 have high comonomer contents, and their MSL distribution profiles display unimodality. M7 has a lower peak value of 33 and a narrow MSL distribution, resulting in a Tm lower than that of M8 and M9. The MSL and its distribution are also key points that influence the melting behavior of copolymers. Sometimes, MSL and its distribution of copolymers have a greater impact on it than the total comonomer contents, which is different from traditional views.

Application of Successive Self-nucleation and Annealing to Study the Stereo-defects Distribution of Biaxially Oriented Polypropylene

The stereo-defects distribution of polypropylene of the two industry biaxially oriented polypropylene （BOPP） samples T28FE and F28SO with different processing properties was studied through successive self-nucleation and annealing （SSA） technique. It was found that there were more medium isotactic components in sample F28SO, and the isotactic sequence length of polypropylene of sample F28SO was shorter and the isotactic sequence length distribution of polypropylene of sample F28SO was broader, which could be processed well at high-speed orientation during the processing of BOPP films. This result indicates that the isotactic sequence length distribution of polypropylene is related to the processing speed during preparing BOPP films, and the stereo-defects distribution of polypropylene has an important influence on its processing ability.