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Since the establishment of the China (Heilongjiang) pilot free trade zone, the development of cross-border e-commerce with Russia has continued to increase speed and quality. With its geographical advantages and its comparative advantages in the Internet field, Heilongjiang Province promoted the rapid development of the Internet economy in Russia, fostered a new digital trade format represented by cross-border e-commerce, and promoted online and offline collaborative promotion of customs clearance logistics and financial services. The paper expounds foundation and development status of Heilongjiang Province’s cross-border e-commerce, analyzes in integrated development of digital economy with the Heilongjiang Province’s cross-border e-commerce with Russia, and further puts forward prospects and recommendations.

As one of the nine border provinces in the country, Heilongjiang Province has 2,981 kilometres of RussianRussian border and 25 national first-class ports. In the past five years, Heilongjiang Province, based on the prominent geographical position in the core of Northeast Asia, has actively promoted the national strategy of the Belt and Road Initiative, deepened on open cooperation with countries in the Northeast Asia, and focused on developing economic cooperation and trade with Russia while building a new pattern of openness to the outside world. This paper in detail elaborates the progress of Heilongjiang Province’s participation in the Belt and Road Initiative (BRI) in aspect of “five links” construction, namely, policy coordination, connectivity of infrastructure, unimpeded trade, financial integration and closer people-to-people ties, since the implementation of the Belt and Road Initiative in 2013, and further proposes feasible countermeasures.

AIMS The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) has been widely adopted since its introduction. In this study, we aimed to report our experience using this reporting system at a College of American Pathologists (CAP)-accredited hospital laboratory in a large series of Chinese patients. METHODS All patients who underwent preoperative ultrasound-guided thyroid fine-needle aspiration (FNA) from January 2011 to August 2016 were retrospectively analyzed. Thyroid FNAs were classified according to the Bethesda System. For patients who underwent subsequent surgery at our institution, the diagnostic performance of the preoperative FNA was further analyzed according to four different calculation criteria. All of the follicular variants of papillary thyroid carcinoma specimens were reviewed to exclude NIFTP (noninvasive follicular thyroid neoplasm with papillary-like nuclear features). RESULTS A total of 13 351 thyroid FNAs were included in this analysis. Of the 12 530 sampled patients, 3594 (28.7%) underwent thyroidectomy, and the malignancy rates for each cytological category were as follows: 66.7% unsatisfactory, 14.2% benign, 53.5% undetermined significance, 30.2% follicular neoplasm, 82.0% suspicious, and 99.1% malignant. Only 12 (0.36% of all PTC) patients were reclassified as having NIFTP. The sensitivities of the preoperative FNAs were all above 95.0% and were as high as 99.0%. The specificities ranged from 50.3% to 63.9%, depending on which criteria were used. The positive predictive value was 95.4% for criteria 1 and 2 and was 94.2% for criteria 3 and 4. The negative predictive values ranged from 64.5% to 85.8%. The diagnostic accuracies all exceeded 90.0%, with the highest being 94.8%. CONCLUSION This study revealed the great efficacy and accuracy of TBSRTC in a large Chinese population for the first time.

Self-piercing riveted (SPR) connections are gradually being used in cold-formed steel structures due to higher tensile strength, shear strength and connection efficiency compared to those of self- drilling connections. With the purpose of investigating the flexural behavior of truss beams with SPR connections and studying the effects of height and span, as well as diagonal web arrangement, on their flexural stiffness and ultimate bearing capacity, the symmetric vertical static load test was conducted for 5 cold-formed thin-walled truss beam specimens with SPR connections. The finite element software was adopted to simulate the test models, and the more parameters were additionally analyzed. The research indicated that the failure modes of the specimens can be divided into two types: the local strength failure mode occurred when the upper chord flange plate was cracked, the other one occurred when the rivets at joints of truss beams were stripped from the plate. The span-height ratio, spacing of web members, chord thickness and number of rivets had great influence on the flexural stiffness and ultimate bearing capacity of truss beams with SPR connections, while the thickness of web members and the arrangement of diagonal web members had less influence. The truss beam was a simply supported beam with a weak web. A theoretical formula was proposed to calculate the equivalent flexural stiffness of the truss beam with SPR connections based on parametric analysis, and it agreed with the experiment results, so the proposed theoretical formula is valid and can be applied to practical engineering.

In order to introduce self-piercing rivet (SPR) technique to component connections of thin-walled steel structures, 78 SPR joints were tested to evaluate their quality and the shear strength. Parameters included in this test program were the sheet thickness, and the rivet. Based on test results, the research developed an empirical formula between the combination thicknesses of sheet and rivet length, and proposed quality evaluation standard of SPR connections and a new design method of shear strength. The test results showed that sheet thickness and sheet thickness ratio had a great effect on failure mode, and rivet length was a key factor on shear properties of SPR connections. The proposed quality evolution standard and design calculation method of shear strength in this paper had certain reasonability and reliability.

The paper presents an experimental investigation on the shear strength of self-piercing rivet connections used in thin-walled steel structures. The test program included specimen variations in the number of rivets in each connection, rivet spacing, end distance, and steel sheet thickness. According to the experimental results, the curve of load-slip, peak load, and failure mechanism for all specimens were analyzed. Parameters of riveting in terms of end distance, spacing, arrangement, length, and thickness difference between connection components were studied on their effects for shearing performances of self-piercing rivet connections. A design method based on the model of transmission dynamics of infectious diseases was proposed for calculating the shear strength of the rivet connections. The strength reduction due to the effect of group rivets was considered in the new method.

The World Bank’s Doing Business covers more than 190 economies. By 2019, China’s best ranking is 46. Against the background of the increasingly strong economic globalization, China’s reform must not only adapt to the national conditions, but also to the international standard, so as to create a good international reputation, attract more international investment and promote the sustained and high-speed development of the domestic economy while promoting the rapid improvement of the government’s own capabilities. Based on the assessment method and China’s coordinates of World Bank’s Doing Business as the starting point of logic analysis, this paper attempts to find out the reasons behind the ranking of China’s business environment and proposes targeted solutions based on the analysis framework of “actor-process”.

This paper presents an investigation of the feasibility of self-piercing rivet (SPR) technology for use in cold-formed steel (CFS) structures. The mechanical properties of the joints, floor trusses and prefabricated CFS composite floor modules connected by SPR and self-drilling screws (SDSs) were compared. The failure mode, bearing capacity, stiffness, ductility, ultimate deformation and other performance of CFS specimens connected with SDS and SPR were analyzed. Considering the construction method of CFS structure and the particularity of SPR connection technology, the construction feasibility of SPR connection was analyzed. The results showed that under the same condition, the stiffness and ductility of the SPR joint specimens are significantly better than those of the SDS joint specimens, the bearing capacity of the two are similar, and the ultimate mid-span deflection of the composite floor with SPR specimens is significantly greater than that with SDS specimens. It is highly feasible to use the SPR connection instead of the SDS connection for prefabricated light steel floor system with high stiffness requirements

This study,taking the soil amended with sewage sludge taken from the Northern Wastewater Treatment Plant(Shenyang,China) as research object,investigated the dose-response effects of sewage sludge on chemical form distribution of Cd,Pb,Cu and Zn in soil.Moreover,the bioavailability of different forms of heavy metals in soil amended with sewage sludge was studied by means of Perennial Ryegrass pot experiment.The soil samples amended with sewage sludge with a sludge dosage rate of 0、9.1%、16.7%、28.6%、37.5%、44.4% and 50%(dry weight basis) were designated as CK、S1、S2、S3、S4、S5、S6,respectively.The chelated form,acid-soluble form,exchangeable form and bound form in neutral condition,alkali-soluble form and protein-binding form of heavy metals in soil amended with sewage sludge were extracted with 0.05 mol/L EDTA,0.1 mol/L CH3COOH,0.01 mol/L CaC12,1 mol/L CH3COONH4,0.05 mol/L NaHCO3 and 0.05 mol/L Tris-HCl,respectively.Results showed that the relative content of the chelated form of heavy metals in soil amended with sewage was the highest,accounting for 20.3%—40.0%,followed by alkali-soluble form and bound form in neutral of heavy metals.The contents of the exchangeable form in neutral,alkali-soluble form and protein-binding form of heavy metals were relatively low.The accumulation of Cd,Cu and Zn in ryegrass was found to increase with increase in sludge dosage rate.The highest content of Cd,Cu and Zn in ryegrass roots was observed with a sludge dosage rate of 44.4%,which was 0.3、2.3 and 6.5 times higher than those at control(CK),respectively.In contrast,the accumulation of Pb in ryegrass decreased with the increase in sludge dosage rate.A decrease of 40% in Pb content in ryegrass roots was observed with a sludge dosage rate of 37.5% as compared to the control.In order to assess the bioavailability of metals,correlation analysis using SPSS statistical software was performed to investigate the relationship between the total accumulation of heavy metals in ryegrass and contents of available forms of heavy metals in soil amended with different sludge dosage rate.The results of Pearson correlation coefficient analysis showed that a significantly(P0.01) positive correlation was found between the contents of chelated form of Cu and Zn and plant accumulated metals.The content of heavy metals in ryegrass had significantly positive correlations with the content of Cu and Zn bound form under neutral condition in soil amended with sludge.There were power functions with positive coefficients relationships between the contents of Cd and Zn in ryegrass and the contents of acid-soluble form of Cd and Zn in artificial soil.Whereas,significantly(P0.05) negative correlation was observed between Pb content in ryegrass and available forms of Pb content.The overall correlation data showed that the contents of heavy metals existing in the chelated form,acid-soluble form and bound form under neutral condition in soil amended with sludge correlated with the contents of heavy metals in ryegrass,suggesting that the three available forms of heavy metals might be absorbed and used by ryegrass.Therefore,contents of chelated form,acid-soluble form and bound form under neutral of heavy metals could be used as the indicator of bioavailable fraction in soil amended with sewage sludge.