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【Objective】 Changes in density and hydraulic conductivity of soil not only modulate subsurface hydrological processes but also affect root growth and root uptake of water and nutrients from soil. Understanding the mechanisms underlying their changes is thus critical to mitigating flooding and improving bioavailability of soil water. In this paper we studied how wetting-drying cycles often seen in the field change bulk density and saturated hydraulic conductivity of the soil. 【Method】 Intact (mimicking zero-tillage) and disturbed (mimicking tillage) soil samples were taken from a cropped field. They were then subject to wetting-drying at different frequencies. During and at the end of the wetting-drying cycle experiment, we measured bulk density and saturated hydraulic conductivity of each soil sample. 【Result】 Bulk density of the intact and disturbed soil samples varied in the range of 1.41~1.89 g/cm3 and 1.47~1.85 g/cm3 respectively. The bulk density of intact soils after the first wetting-drying cycle increased significantly followed by slight fluctuations in other wetting-drying cycles, with an average coefficient of variation 8%. In contrast, bulk density of the disturbed soils increased with the increase in wetting-drying cycles, with an average coefficient of variation 5%. Overall, the wetting-drying cycles affected the bulk density of intact soils more significantly than the disturbed soils (P

【Background】 The project of transforming drylands to paddy fields in Sanjiang Plain in the northeast China has increased its rice cultivation areas from 266 700 hm2 prior to the project to 1 733 300 hm2 after implementing the project. As a result, its demand for water also increased. Baoshan Farm is in the upper reach of Sanjiang plain on a piedmont, and its agricultural production had relied on groundwater since its establishment. Since 1992, it has gradually converted drylands to paddy field, and such a land conversion has resulted in a conflict between increased demand for water and limited water availability. 【Objective】 The purpose of this paper is to analyze how to optimize the use of surface water and groundwater to resolve the conflict between limited water supply and the increased demand for water due to the land use change, so as to avoid waterlogging while in the meantime alleviating continued groundwater table dropping. 【Method】 The calculation was based on groundwater flow with the groundwater dynamics under different managements simulated using the software Modflow-2000. The aquifer parameters, model validation and sensitivity analysis of the parameters were carried out using long-term hydrogeological data measured from the area. We then compared groundwater dynamics under irrigations using different combinations of surface water and groundwater. 【Result】 The calibrated groundwater dynamics model correctly reproduced the measured changes in groundwater level in the studied area; sensitivity analysis revealed that the initial groundwater level did not have a noticeable influence on long-term groundwater variation. Using the river water to irrigate areas 10 km in the proximity of the river while irrigating other areas using the groundwater can keep groundwater resource balance while in the meantime alleviating waterlogging. In contrast, irrigating too many areas using transferred river water could raise the groundwater table and result in waterlogging in a wide range of areas. 【Conclusion】 Rational use of groundwater and surface water in irrigation can maintain groundwater balance and avoid waterlogging in the farmlands of Baoshai; a monitoring system should be in place to timely measure the change in groundwater table.

【Objective】 Water flows over the soil surface and its infiltration in soil are two important parameters for irrigation design, and they are modulated by a multitude of biotic and abiotic factors. The aim of this paper is to investigate the advance and recession of water over the soil surface, as well as its infiltration in soil under border irrigation in attempts to provide a guidance to help border irrigation design. 【Method】 The analysis was based on both experiment and numerical simulation. A field experiment was conducted in borders grown with rotated maize and winter wheat. In the experiment, we measured spatiotemporal changes in both soil water and advance and recession of surface water inside the borders. The experimental data were used to calibrate and test the WinSRFR model to simulate water flows. 【Result】 The numerical model correctly reproduced water flow in both soil and over the soil surface, with the root mean square errors for advance and recession of the surface water in the border ranging from 0.05 to 0.41 h and 0.06 to 0.71 h, respectively, which accounted for 1.23%~7.16% and 1.21%~23.37% of the advancing and recessing time respectively. Crop type affected water flows, and water advancing speed over the soil surface in irrigating the winter wheat was 23.99% slower than irrigating the summer maize. Compared with the summer maize, the winter wheat increased soil water infiltration coefficient and surface roughness by 5% and 39.1% respectively, while reducing soil infiltration index by 34.61%. Curve fitting revealed that the infiltration coefficient was linearly related to the irrigation duration with R2 = 0.903 6. 【Conclusion】 The WinSRFR model was accurate to simulate water flow over the soil surface and its infiltration under border irrigation. Repeating irrigations gradually reduced the infiltration coefficient, infiltration index and surface infiltration capacity, thereby improving irrigation efficiency and uniformness. The infiltration coefficient was linearly related to irrigation duration.

Deformation and phase transformation are two major topics in the study of titanium alloy materials. Titanium alloys usually require a series of complex thermo-mechanical treatments to obtain a microstructure corresponding to service performance. Its hot deformation behavior is a typical thermo-mechanical coupling process. Deformation and phase transformation may occur simultaneously and affect each other. It is one of the current research hotspots. However, due to the inevitable existence of dynamic recovery / recrystallization, microstructure fragmentation / spheroidization, a large number of deformation defects, deformation texture, and stress-induced phase transformation during hot deformation, coupled with the changes of the phase transformation kinetics characteristics and the crystallographic mechanism of the variant selection under thermo-mechanical coupling, directly leads to the extremely complicated dynamic phase transformation behavior of the titanium alloy during the hot deformation process, and it becomes quite difficult to reveal its evolution law in depth. This paper summarizes the main characteristics and laws of titanium alloy deformation and phase transformation in view of the dynamic phase transformation behavior of titanium alloy during hot deformation,mainly introduces the research progress of the dynamic phase transformation of the titanium alloy under the thermo-mechanical coupling from the three aspects of precipitation phase morphology characteristics, variant selection mechanism and phase transformation kinetics characteristics, and summarizes and prospects its research and development trend.

This article reviewed the development and research progress in polyimide (PI) all over the world. The key preparation technologies and application fields of PI are introduced according to the main products such as film, slurry, resin, fiber and foam. Through analyzing the gaps of R&D and production status between the domestic and foreign countries, the future development trends and research focus of PIs were proposed. [ABSTRACT FROM AUTHOR]

Free port is an ancient economic phenomenon, born from cross-regional commodity exchange. As a part of the international trade sy stem, free ports' development is under the influence of the international system reform and in stitution transition. At different stages of human history, the forms and functions of free (port) zones are changing and expanding, complying with diverse international political and economic rules. Among all the institutions that are designed to maintain the polity, the tariff system has the closest relation with the evolution of free ports. The history of original free port and original tariff can be traced back to ancient Europe. With decentralized powers and non-universal tariff system, the original tariff was hardly able to play a role in trade restriction, let alone the trade facilitation of original free ports in ancient Europe. The public authority in medieval Europe was based on a combination of universal theocracy and divided feudal hierarchy. The latter made it difficult for an integrated and standardized national tariff system to be established. The heavy exploitation caused by internal tariff systems gradually impeded market economy development. The emerging merchant class was eager to breach the tariff restriction. Some Commerce Guilds bought special permission of tariff exemption from feudal lords. Therefore, free ports and free cities were founded based on such franchise. With the enhancement of European Monarchial Power and the decline of Feudal System, European local tariffs had developed into modern national tariffs which were more systematic and standardized. After the opening of new sea routes, rapidly accumulated commercial capital promoted the unification of domestic markets around Europe and the formation of overseas markets. With European capitalism expanding into the whole world, some countries in advantage positions began to open their port cities or harbors in their colonies as free ports or free trade zones to promote external trade. After World War II, the development of economic globalization, trade liberalization and regional integration created a favorable international environment for free ports and free trade zones. New free ports/zones were established worldwide in new forms such as EPZs and SEZs, and existing free ports continuously improved themselves to adapt to new international trade rules. Compared with other regions focusing on the vast construction of new free ports or free trade zones, the EU put more emphasis on the enhancement of efficiency. The environment of European free ports has changed a lot owing to the foundation of European Customs Union, European single market, as well as multilateral and plurilateral trade agreements signed under the rules of WTO. The publishment of New Union Customs Code by EU in 2008 put an end to the tariff exemption privileges in European free ports. The close of free port zone in Hamburger Harbor shows the fading of free ports in Europe. Though it seems to be an inevitable outcome due to international trade liberalization and the European tariffs integration, free ports' function and form will still evolve as long as the international tariff, non-tariff barriers and national customs security threats exist. From an innovative perspective, the evolution of free ports will be regarded as a historical process and be analyzed in the international system. We try to reveal the correlation between free ports evolution and European tariff system transition, and outline the development trend of free ports with methods of historical analysis and system level analysis. As the interactive relation of the elements within the international system facilitating free ports' evolution is also an important complementary, related research can be conducted on the next stage. With regard to further work, the study of the correlation between the world free ports and the existing international systems and national institutions, especially international trade order and modern customs policies can be non-negligible topics. [ABSTRACT FROM AUTHOR]

Over the past 30 years, the Zhejiang Provincial Government has made reforms to expand the powers of the county government, by increasing the number of sub-provincial governments through a financial system of province directly-administrated counties, implementing growth-oriented fiscal policies, enlarging the economic power of rich counties, and reforming personnel management system. The reform measures have built an incentive structure for sub-provincial governments. There is a mutual coupling effect between the incentive structure for the sub-provincial government and the development of a private economy such that the county-level economies of Zhejiang Province have been sufficiently rapid. In such circumstances, the county-level economies of Zhejiang Province are shaped by many prosperous massive economies,each divided along county boundaries. This led to regional segmentation and weakened cities' ability to gather production factors. In the meantime, the shortage of market supply has been replaced by excess production capacity, and capital scarcity replaced by capital spillover. For the purpose of achieving an economic transformation and upgrading industry, it is essential to design a new incentive structure for sub-provincial governments. [ABSTRACT FROM AUTHOR]

Industrial biotechnology is an integrated technology that utilizes biochemical reactions and biofunctions to achieve substance synthesis and energy conversion. The development of industrial biotechnology supports a green, efficient, and new route for manufacturing of chemicals using renewable raw materials. It is expected to bring a fundamental shift in industrial manufacturing and a change in economic growth mode. Industrial biotechnology is an important strategic technology supporting the sustainable development of social economy and has become a focus of global competition on science and technology. Based on an elaboration of industrial biotechnology's deep integration in bioeconomy, this paper summarized the current situation and developmental trends of industrial biotechnology and biomanufacturing industry in China. Gaps between developed countries and China as well as key areas for biotechnology development were proposed, followed by identifying tasks and directions for future development of biomanufacturing industry.

Objective: To construct an expression vector for alkaliphilic Bacillus sp. N16-5., Methods: Bacillus subtilis expression vector pHCMC04 was used as a backbone. Its xylose-inducible promoter cassette was replaced by the constitutive promoters P43 (from B. subtilis) and P(EF) (from Bacillus sp. N165), separately, resulting in two expression vectors pABN165P43 and pABN165P(EF). Green fluorescent protein gene gfp was linked to the two vectors as a reporter gene. Fluorescence microscope and multifunctional fluorescent reader were used to test the expression efficiency of the system., Results: Green fluorescence was visualized in Bacillus sp. N16-5 with pABN165P(EF)-gfp or pABN165P43-gfp. Quantitative data analysis revealed that fluorescence was first detected around the 7th hour. The fluorescence intensity increased rapidly from the 7th hour to the 12th hour and reached the maximum at about the 12th hour., Conclusion: Two expression vectors for Bacillus sp. N16-5 have been constructed, allowing expression of exogenous protein in alkaliphilic Bacillus sp. N165.