African Trade Beads

First crafted and worn 120,000 years ago,beads began as adornments made from natural materials such as stones,shells,and wood.Over time,they evolved in purpose,serving as currency and burial offerings.

A Trade War With No Winners

US President-elect Donald Trump is set to ignite new trade wars with some other countries,including China.His announcement on social media on 25 November 2024 that he would impose additional tari"s on goods from China,Canada,and Mexico came as no surprise.

Foreign Trade Hits New High

China’s foreign trade hit a record high in total value in 2024 as the world’s second-largest economy further consolidated its top position globally in goods trade.The nation’s total goods imports and exports in yuan terms reached about$6.1 trillion last year,up 5 percent year on year,according to data released on 13 January by the General Administration of Customs(GAC).

Diversity-multiplexing tradeoff of half-duplex multi-input multi-output two-way relay channel with decode-and-forward protocol

A multi-input multi-output(MIMO) separated two-way relay channel(STWRC) is considered,where two users exchange their messages via a relay node.When each link is quasi-static Rayleigh fading,the achievable diversity-multiplexing tradeoff(DMT) of the half-duplex STWRC is analyzed.Firstly,the achievable DMT of the STWRC with static decode-and-forward(DF) protocol is obtained.Then,a dynamic decode-and-forward(DDF) protocol for the STWRC is proposed,where the relay listening time varies dynamically with the channel qualities of the links between two users and the relay.Finally,the achievable DMT of the proposed DDF protocol is derived in a case-bycase manner.Numerical examples are also provided to verify the theoretical analysis of both protocols.

A Retrodirective Array Enabled by CMOS Chips for Two-Way Wireless Communication with Automatic Beam Tracking

This article proposes and demonstrates a retrodirective array(RDA)for two-way wireless communication with automatic beam tracking.The proposed RDA is enabled by specifically designed chips made using a domestic complementary metal-oxide semiconductor(CMOS)process.The highly integrated CMOS chip includes a receiving(Rx)chain,a transmitting(Tx)chain,and a unique tracking phaselocked loop(PLL)for the crucial conjugated phase recovery in the RDA.This article also proposes a method to reduce the beam pointing error(BPE)in a conventional RDA.To validate the above ideas simply yet without loss of generality,a 2.4 GHz RDA is demonstrated through two-way communication links between the Rx and Tx chains,and an on-chip quadrature coupler is designed to achieve a nonretrodirective signal suppression of 23 dBc.The experimental results demonstrate that the proposed RDA,which incorporates domestically manufactured low-cost 0.18 lm CMOS chips,is capable of automatically tracking beams covering±40with a reduced BPE.Each CMOS chip in the RDA has a compact size of 4.62 mm^(2) and a low power consumption of 0.15 W.To the best of the authors’knowledge,this is the first research to demonstrate an RDA with a fully customized CMOS chip for wireless communication with automatic beam tracking。

Reference-frame-independent quantum key distribution with two-way classical communication

The data post-processing scheme based on two-way classical communication(TWCC)can improve the tolerable bit error rate and extend the maximal transmission distance when used in a quantum key distribution(QKD)system.In this study,we apply the TWCC method to improve the performance of reference-frame-independent quantum key distribution(RFI-QKD),and analyze the influence of the TWCC method on the performance of decoy-state RFI-QKD in both asymptotic and non-asymptotic cases.Our numerical simulation results show that the TWCC method is able to extend the maximal transmission distance from 175 km to 198 km and improve the tolerable bit error rate from 10.48%to 16.75%.At the same time,the performance of RFI-QKD in terms of the secret key rate and maximum transmission distance are still greatly improved when statistical fluctuations are considered.We conclude that RFI-QKD with the TWCC method is of practical interest.

Temporal and spatial evolution of global major grain trade patterns

The complex and volatile international landscape has significantly impacted global grain supply security. This study uses a complex network analysis model to examine the evolution and trends of the global major grain trade from 1990 to 2020, focusing on network topology, centrality ranking, and community structure. There are three major findings. First, the global major grain trade network has expanded in scale, with a growing emphasis on diversification and balance. During the study period, the United States, Canada, China, and Brazil were the core nodes of the network. Grain-exporting countries were mainly situated in Asia, the Americas, and Europe, and importing countries in Asia, Africa, and Europe. Second, a significant increase in the number of high centrality countries with high export capacity occurred, benefiting from natural advantages such as fertile land and favorable climates. Third, the main global grain trade network is divided into four communities, with the Americas-Europe community being the largest and most widespread. The formation of the community pattern was influenced by geographic proximity, driven by the core exporting countries. Therefore, the world needs to enhance the existing trade model, promote the multi-polarization of the grain trade network, and establish a global vision for the future community. Countries and regions should participate actively in global grain trade security governance and institutional reform, expand trade links with other countries, and optimize import and export policies to reduce trade risks.

Beamforming Design for IRS-and-UAV-Aided Two-Way Amplify-and-Forward Relay Networks in Maritime IoT

In this paper,an intelligent reflecting surface(IRS)-and-unmanned aerial vehicle(UAV)-assisted two-way amplify-and-forward(AF)relay network in maritime Internet of Things(IoT)is proposed,where ship1(S1)and ship2(S2)can be viewed as data collecting centers.To enhance the message exchange rate between S1 and S2,a problem of maximizing minimum rate is cast,where the variables,namely AF relay beamforming matrix and IRS phase shifts of two time slots,need to be optimized.To achieve a maximum rate,a low-complexity alternately iterative(AI)scheme based on zero forcing and successive convex approximation(LC-ZF-SCA)algorithm is presented.To obtain a significant rate enhancement,a high-performance AI method based on one step,semidefinite programming and penalty SCA(ONSSDP-PSCA)is proposed.Simulation results show that by the proposed LC-ZF-SCA and ONS-SDP-PSCA methods,the rate of the IRS-and-UAV-assisted AF relay network surpass those of with random phase and only AF relay networks.Moreover,ONS-SDP-PSCA perform better than LC-ZF-SCA in aspect of rate.

Impact of BRICS Trade Facilitation on China's Exports Using Cross-Border E-Commerce

With the rapid growth of the global digital economy, cross-border e-commerce, as an emerging form of trade, has gradually become a powerful engine to promote the development of global trade. BRICS is an important force in the global economy, and the progress of the BRICS countries' trade facilitation level has an important impact on the global trade environment. This paper conducts an in-depth study of the dynamic changes in BRICS trade facilitation from 2013 to 2022, and uses an extended gravity model to analyze the specific impact of this change on China's exports using cross-border e-commerce. The results show that although the BRICS countries have made some progress in trade facilitation, the overall level still needs to be improved, and there are obvious differences among member countries. However, the improvement of trade facilitation among BRICS countries has undoubtedly brought significant positive effects to China's exports using cross-border e-commerce.

Sharing Smart Services,Jointly Promoting Trade Development

In 2024,the China International Fair for Trade in Services (hereinafter referred to as CIFTIS) opened in the China National Convention Center and Shougang Park on September 12th.The theme of the CIFTIS this time was"global services,shared prosperity",which is not only a window for allowing the world to discover the development of China's service trade,but is also a bridge for promoting global cooperation with regards to the service trade.As one of the world-famous service trade events,the CIFTIS has become an important business card allowing China to open up.The CIFTIS has attracted the attention of the whole world and become a bridge for all parties to share development opportunities,promote industrial growth,and strengthen communication.

World Trade Organization Reform and the Role of the Global South

Under the impact of unilateralism and protectionism,trade disputes among countries have increased in recent years,bringing uncertainty to global trade and jeopardizing the multilateral trading system.The World Trade Organization(WTO)plays a crucial role in the development of the global economy and trade.It also plays a key role in maintaining a fair,open and sustainable international trade environment,and provides a solid foundation for the development of global economy and trade.As the Global South has played an important role in promoting WTO reform and safeguarding the rights and interests of developing countries,it’s important to further strengthen its solidarity,actively participate in the reform of the global trade governance system and promote the building of a more open,fair and balanced global trade environment.

Production and trade trend of oils and oilseeds in BRICS countries

In order to promote agricultural production and trade cooperation among BRICS countries,and ensure the security and stability of the oils and oilseeds industrial and supply chains in China and the world,the production,consumption,trade trend,and cooperation potential of oils and oilseeds in BRICS countries were expounded,and relevant policy recommendations were put forward.Most of the BRICS countries are major agricultural producers,and they are also important agricultural product consumption markets in the world.In 2023/2024,the production and consumption of oilseeds in BRICS countries account for nearly half of the world's total;the production of vegetable oils exceeds a quarter of the world's total,and the consumption of vegetable oils accounts for 40%of the world's total.In 2023/2024,the import and export volume of oilseeds exceeds half of the world's total;vegetable oil imports account for 40%of the world's total,and exports account for about one tenth of the world's total.China's imports of oilseeds and oils from BRICS countries account for 68%and 29%of its global imports in 2023,respectively.BRICS countries are rich in agricultural land resources,have great potential for oils and oilseeds production,obvious complementary advantages in trade structure,and huge space for future cooperation.It is suggested that Brazil should be included in the"Belt and Road"co-construction category to promote the continuous deepening of agricultural cooperation between China and Brazil.It is suggested to explore regional agricultural trade agreements among BRICS countries,promote currency settlement and exchange among BRICS countries,and enhance the facilitation and stability of BRICS trade.It is suggested that China should increase its investment in BRICS countries and export advanced technology and management experience to benefit local agricultural development and achieve a mutually beneficial and win-win situation.

Specialization or Diversification:Which is More Conducive to Foreign Trade Resilience?Evidence from China-Russia Border Regions in Northeast China

Under the background of complex international situation,how to build the special geo-economic space of China-Russia bor-der lies in strengthening their foreign trade resilience against external shocks.Based on empirical evidence from ten prefecture-level China-Russia border regions in Northeast China,this paper analyzed the spatiotemporal evolution of foreign trade resilience under different shocks.Furthermore,through the Panel Regression model,the mechanism of the industrial structure on the foreign trade resilience in contraction period and expansion period was discussed.The results showed that:1)from 2004 to 2021,foreign trade in China-Russia border regions experienced five phases.The overall foreign trade resilience was higher than expected,showing a rising volatility trend,but there was significant spatial heterogeneity in the ability of cities to cope with shocks.2)Highly specialized clusters were mainly concentrated in Yichun,Heihe and Da Hinggan Ling Prefecture,while Mudanjiang and Yanbian performed better in related and unrelated diversification.3)In different stages of economic system evolution,the response mode,degree and result of border foreign trade resilience to regional industrial structure showed obvious stage characteristics.During the contraction period,related diversification was more conducive to improving the resistance through risk spillovers.During the expansion period,specialization played a more significant role in improving regional resilience through self-reinforcing effect.These results are beneficial for expanding the resilience theory,ensuring border economic security and optimizing border industrial investment layout.

Security-Reliability Analysis and Optimization for Cognitive Two-Way Relay Network with Energy Harvesting

This paper investigates the security and reliability of information transmission within an underlay wiretap energy harvesting cognitive two-way relay network.In the network,energy-constrained secondary network(SN)nodes harvest energy from radio frequency signals of a multi-antenna power beacon.Two SN sources exchange their messages via a SN decode-and-forward relay in the presence of a multiantenna eavesdropper by using a four-phase time division broadcast protocol,and the hardware impairments of SN nodes and eavesdropper are modeled.To alleviate eavesdropping attacks,the artificial noise is applied by SN nodes.The physical layer security performance of SN is analyzed and evaluated by the exact closed-form expressions of outage probability(OP),intercept probability(IP),and OP+IP over quasistatic Rayleigh fading channel.Additionally,due to the complexity of OP+IP expression,a self-adaptive chaotic quantum particle swarm optimization-based resource allocation algorithm is proposed to jointly optimize energy harvesting ratio and power allocation factor,which can achieve security-reliability tradeoff for SN.Extensive simulations demonstrate the correctness of theoretical analysis and the effectiveness of the proposed optimization algorithm.

Down to Business:How the upgraded China-ASEAN Free Trade Area(CAFTA 3.0)will foster trade and investment cooperation

Last October,the leaders of China and the 10 ASEAN member states announced a substantial conclusion of negotiations on an upgraded version of the China-ASEAN Free Trade Area(CAFTA 3.0).The negotiation teams formulated a work plan for an upgraded protocol to be signed and expedited follow-up work in preparation for an official signing in 2025.

Creating a Climate for Sustainable Trade

With climate change becoming direr and the WTO“losing its teeth”at 30,experts renew call for green collaboration among the world’s three largest economies.THIS year marks the 30th anniversary of the World Trade Organization(WTO),which has played an indisputable role in facilitating global trade and boosting global growth.The WTO has a significant role in the era of climate change as it provides a platform for resolving green trade disputes.

Policies Aiming at Stabilizing Foreign Trade Continue to Work

On May 30,t he Ch ina Council for the Promotion of International Trade(CCPIT)held a regular press conference.Zhao Ping,the spokesperson for the CCPIT,said that since the beginning of this year,the number of issued ATA Carnets has increased significantly,reflecting the fact that China’s foreign trade policy portfolio is taking effect,foreign trade enterprises have been more active,and their motivation and enthusiasm for expanding the international market have continued to rise.

How Can Foreign Trade Be Stabilized?

At an economy-themed press conference held on the day of the Second Session of the 14th National People's Congress,Minister of Commerce Wang Wentao admitted that the situation of foreign trade situation is still"very severe"this year.When it comes to the future policies for stabilizing foreign trade,Wang Wentao said that the government will provide better financial services forforeign trade enterprises.

Facilitating Trade Across Borders

“The Government Work Report noted that‘development of the New International Land-Sea Trade Corridor will be accelerated’,”stated Wei Zhaohui,member of the Standing Committee of the 14th National Committee of the Chinese People’s Political Consultative Conference(CPPCC)and director-general of the Guangxi International Expo Affairs Bureau,in an interview after the Second Session of the 14th National People’s Congress on March 5.

Next-Level Relations China-Laos Economic and Trade Cooperation Exchange Conference fortifies bilateral economic ties

On September 5,the ChinaLaos Economic and Trade Cooperation Exchange Conference,themed"Highlevel Opening-up and Building a China-Laos Community with a Shared Future,"took place in Vientiane,capital of Laos.The purpose of the conference was to review the achievements of bilateral economic and trade cooperation and work together to develop the roadmap to high-quality development of China-Laos economic and trade cooperation by focusing on shared goals,pooling strength,and adhering to results-oriented collaboration.