With the support of the Academic Division of the Chinese Academy of Sciences, a task force headed by Prof. DUAN Xue, a CAS Member from Beijing University of Chemical Technology, has conducted studies on the development of safe plastics. The following paragraphs summarize the suggestions of the task force to the central authorities.

1. Plastic as an important fundamental material

Thanks to its excellent physical properties, good malleability and high cost-effectiveness, plastic is widely used in a variety of sectors ranging from architecture, civil Engineering, home appliance manufacturing, cable and wire products to agriculture and health care. High-performance engineering plastic and its composites, in particular, are playing a key role in cutting-edge industries such as microelectronics,space and nuclear energy.

The past decade has witnessed double-digit growth of China's plastic processing industry. From 2003 to 2014,its output value grew 20.62% annually, much higher than the national average for industrial productivity. In 2015,the output of plastics in China reached 75.60 million tons,exceeding all other countries in terms of both production and consumption. Clearly, plastic is fundamentally important materials in this country.

2. Hazardous substances in plastics

(1) Sources

Many additives are commonly used in the different stages of plastic production so as to meet the requirements of its synthesis, molding, processing and performance. There are more than 2,000 kinds of such additives and byproducts from synthesis and molding processes in a total of 13 categories. Of this number,more than 100 are toxic and therefore harmful, including catalyzers, heat stabilizers, lubricants, plasticizers,antioxidants, initiators and fl ame retardants.

很多施工单位在进行施工设计时施工技术不过关导致出现渗漏问题：①施工单位施工人员技术不过关，根据其主观性进行施工，使用一些不合理不科学的防水施工技术。②施工单位为节省时间，或者节省成本，往往会忽略一些施工环节，不能按部就班的完成各个工序。③施工单位不重视防渗漏施工，对施工人员也没有进行相关的专业培训。这些都是导致出现渗漏问题的重要原因。

Hazardous substances of plastics pose extensive and long-term threats to people's health and environmental safety. Their effects are more significant in infants and elderly people. Over the past 10 years they have resulted in many social incidents both at home and abroad, such as toxic toys in 2007, plasticizers and bisphenol A (BPA)baby bottles in 2011 and toxic running tracks in 2014.

3. Current laws, regulations and standards concerning hazardous substances in plastics in China and around the world

(1) In developed countries

A. Basic research

In the European Union legal frameworks and systems of standards have been established and steadily improved.Since 2003, the EU has successively issued RoHS(restrictions on the use of certain hazardous substances in electrical and electronic equipment) and REACH(regulations concerning the Registration, Evaluation,Authorization and Restriction of Chemicals), which applies to more than 30,000 chemicals, including food contact materials, electrical and electronic equipment,toys, scrap electrical and electronic equipment, textile products and related materials. The restriction standards have become increasingly strict. While setting ever higher green trade barriers for large commodities from non-EU countries, such standards significantly raise the monitoring and restriction levels of various hazardous substances in plastics.

It is specified in the RoHS issued in 2003 that electrical and electronic equipment containing six kinds of hazardous substances (hg, Pb, Cr VI, Cd, PBDEs,PBBs) are not allowed to enter the EU market. The implementation of RoHS has had a huge impact on China's export industry. The REACH regulations issued in 2007 have had a much wider influence than RoHS.

China's laws, regulations and standards in the field have mainly followed those in developed countries such as the EU countries and the US. For instance,after RoHS the Chinese Ministry of Industry and Information Technology promulgated Requirements for Concentration Limits for Certain Hazardous Substances in Electronic Information Products and Marking for the Control of Pollution Caused by Electronic Information Products. In general, they cannot meet the requirements of effective monitoring and restriction of those substances at the national level. There is a lack of comprehensive legislation and consistent overcharging design built into the control of those substances at the national level.

B. Technology development

(2) Relevant laws, regulations and standards in China

4. The status quo of China’s research and development of technology for finding substitutes for hazardous substances in plastics

To address the problem of the health and environmental impact of hazardous substances in plastics, Chinese scientists and engineers have implemented basic and applied studies. The result is the development of a series of green synthesis and molding technologies and some additives with little or no toxins. However, the research is limited by a shortage of strategic guidelines for setting objectives and devising development programs.Furthermore, key national programs lack unified planning for basic and industrial application research,which severely limits the promulgation, dissemination of technological results.

5. Recommendations for restricting the use of hazardous substances in plastics

It is advisable to assign priority to the following three tasks in order to promote structural realignment to a green and sustainable future for relevant industries.

(2) Social incidents caused by hazardous substances in plastics

(1) Overarching design

It is advisable to formulate a long- and midterm development plan and an early-warning system.Efforts should be made to prepare a roadmap for the replacement of hazardous substances so as to strengthen and monitor the enforcement of the relevant plans. It is important to make suitable connections between up- and down-stream studies and between basic research and application sections.

A joint committee should be established under the coordination of the China Petroleum and Chemical Industry Federation and China Plastics Processing Industry Association and should include the participation of such organizations as the National Development and Reform Commission, the Ministry of Industry and Information Technologies, the Ministry of Science and Technology, and the National Natural Science Foundation of China. Its tasks include the formulation of relevant regulations and standards and making plans for research and development programs.

B. Planning and implementation

A. Strengthen organizational guarantee

(2) Facilitate innovation-driven development

794 Correlation between chronic hepatitis B virus infection and coronary heart disease

抓住国家加大农业、农村基础设施投资的机遇，千方百计多渠道争取资金。精准农业应用系统投资较大，一套精准节水灌溉系统下来要在10万元以上。一是要探索整合财政支农资金方式。统筹安排使用支农资金，围绕发展主导精准农业进行整合，通过资金整合，既有利于集中财力办大事，也有利于发挥财政资金“四两拨千斤”的作用。二是拓宽精准农业投入来源渠道。进一步优化农村投资环境，吸引民间资本更多地投向精准农业[2]。加快农村金融组织、产品和服务创新，扶持农业信贷担保组织发展，扩大农村担保品范围。加快发展农业保险，政策性保险与商业保险相结合，健全农业再保险体系。

经过对设计不断优化,利用ISE自带的静态时序分析工具进行分析得知[14],该设计可以最高跑在150 MHz。对算法模块进行资源消耗分析发现,占用的slice资源占FPGA可用的slice总数的13%,用到的IOB占可用IOB总数的18%,Block Ram的使用占9%,BUFG占用数量为8,DSP48E消耗了33个。因为算法中有很多乘法运算,可以采用一些特殊的乘法器结构减少DSP48E的消耗。

由表4可知，挖金沟的水系沉积物中Cu元素的含量从上游到下游先增大后减小，因为上游到中游之间有挖金沟矿山，所以含量先增加，随着离矿山的距离便远，含量逐渐减少，但由于矿山靠近上游，含量总体上游大于下游。海底沟从上游到下游也是先增大后减小，因为下游靠近海地沟矿区本部，所以总体趋势增大。江浪沟下游靠近矿区本部，所以含量逐渐升高。说明水系沉积物中金属元素含量在矿区附近含量较高，在远离矿点的区域，会随着水流方向逐渐降低。掌握了这些规律，就可以在GIS工具的辅助下采集更少的点来对矿区的污染程度进行评价，从而节省采样和化验的费用，符合经济效益。

It is advisable for the National Natural Science Foundation of China to set up key research programs to support the joint industrial research centers to conduct basic and systematic studies and original and directional research.

当前，相关研究积累的文献相对来说并不多。陈廷贵等(2018)研究了我国1998-2007年农副食品加工业的TFP变动，并分地区、分企业进行了对比分析。叶刘刚和黄静波(2016)采用OP方法，研究了1999-2011年农副食品加工企业的TFP，并重点分析不同所有制企业的差异。基于17个行业数据，李鹏和曾光(2012)以2003-2009年为着眼点，重点探讨了农副食品加工业的TFP变动，发现技术进步对其发展存在推动作用。之后，李鹏和曾光(2014)采用三阶段DEA模型，进一步对2009年的细分行业数据进行了具体研究，对效率进行测度、评价和系统分析。

It is advisable for the Ministry of Science and Technology to coordinate industrial research into 15 key projects in three categories and for the Ministry of Industrial and Information Technology and other relevant organizations to launch technology commercialization projects.

C. Industrial layout

平民非虚构写作热与纯文学处境尴尬有直接关系。尴尬的纯文学处境，为平民非虚构写作热提供了契机。1980年代文学界倡导纯文学，旨在把文学从“政治标准第一，艺术标准第二”的束缚中解放出来，同时强调纯文学是有别于通俗文学的严肃文学。彼时严肃文学备受瞩目，并形成持续数年的文学热:报纸都辟有专门的文学副刊，百余家出版社每年都出版一定数量的纯文学作品，盛况空前。到了1990年代，纯文学开始走下坡路，每况愈下，时至今日处境愈发尴尬。

Effort should be made to conduct overall planning on the entire industrial chain of molding and processing in which upstream resin is synthesized into downstream products by taking into account of the categories of resin and their applications. It is advisable to set up ten demonstration centers for green processing of plastic in ten categories.

(3) Strengthen policy guarantee

A. Testing methods and specifications

It is important to formulate or revise the testing methods and specifications for hazardous substances in plastics by closely following the development trends of relevant regulations and standards internationally and in line with China's strategy.

B. Forming a system of standards

It is important to formulate relevant standards according to international practice, encourage industrial upgrading and overcome the “green technology barrier”of developed countries. Efforts should be made to form an entire system of standards, upgrade technological levels and pursue voluntary substitution.

香娭毑给人的印象是一个能干婆，可她见了喜姑，妹妹长妹妹短的叫得十分亲热，从不在她面前逞能的。没事的时候，喜姑也喜欢到香娭毑家里来串门。无论白天晚上，刮风下雨，只要喜姑一到，香娭毑就把宝刚爹支走，去去，到外面去，我们姊妹打讲，你到屋里凑什么热闹。

C. Policy and regulations

It is important to formulate a list of toxic and hazardous substances, improve the system of penalties and encourage companies to adopt new technologies and develop new products.

图4为不同水位降时有水开门工况下卧倒门液压缸启闭力变化曲线。从图中可以看出，在有水开门过程中，液压缸在开门初期闸门门顶未入水前(90°～50°开度范围内)其启闭力为拉力，最大拉力出现在开门初始，水位降为0.8，0.5，0.3 m时对应的最大拉力分别为：1 463.7，905.1，558.0 kN；液压缸在门顶入水后开始输出推力，最大推力出现在开门终了时，为211.3 kN。在实际运行过程中，闸门每次启闭时启闭机均未超载，在水位降为0.3 m情况下，液压缸的最大拉力已接近660 kN，可以认为，实际启闭过程中水位降不超过0.3 m。