I. Introduction
In recent years, the British foreign trade surplus continues to expand to the United Kingdom has brought political and economic lot of problems, but also attracted wide attention from scholars at home and abroad. Research shows that the United Kingdom in the international division of labor in which the position is the main reason for British foreign trade imbalances, namely the United Kingdom in the international production networks play a role in processing and assembly ground, a large number of imported intermediate products are processed and exported to overseas assembly, led to a substantial increase in UK exports. Henryk Kierzkowski and Lurong Chen (2007) noted that today, spare parts trade more frequently than the final product, fragmentation of production and outsourcing has become the norm. Tian (2005) believes that the current development of the newly industrialized countries and the British state has come into the international division of labor, not only in the volume of trade within the product to become a significant growth in international trade reasons, but also a change in the pattern of international trade flows are an important force, a British national industrialization and development of industrial structure upgrading in new ways. Cui Wei (2009) under the United Nations BEC Industry Classification Standard intermediate goods imports to the UK size was estimated that the British imported goods mainly for intermediate inputs, the proportion of total imports reached 60%, the UK has to actively join the international product within the division of labor. Sven. W. Arndt (2007) emphasized that now, more and more products are produced in a number of countries, for the analysis of the bilateral trade balance has gradually lost value considering.
In view of the international division of labor in which the United Kingdom's position, imports of intermediate goods export capacity of the United Kingdom will inevitably have a huge impact, this paper aims to analyze the data size of the United Kingdom and the use of intermediate goods imports panel data analysis of its manufactured goods to the UK exports.
Second, the scale of Britain's imports of intermediate goods
In this paper, intermediate goods imports on British exports of manufactured goods, first need to analyze the size of the United Kingdom imported intermediate goods. Since this article focuses primarily on intermediate goods imports on manufactured exports impact analysis, so the corresponding intermediate goods refers to the production of manufactured goods needed intermediate inputs, based on SITC 2 classification criteria, mainly in categories 7 and 8 categories of products (71,72,73,74,75,76,77,78,79,82,87,88,89 of 13 categories), which defines see Francis Ng, Alexander Yeats (1999). From 1987 to the present, the UK's intermediate goods imports have been expanding, the world's total share of total imports of intermediate goods is improving, where the main choice of 1989, 1999 and 2009, three years of data were analyzed, as shown in Figure 1 .
As can be seen from Figure 1, from 1989 to 2009, in addition to 72 classes and 89 classes total world imports of intermediate goods intermediate goods decreased the proportion of total imports, other categories of intermediate goods imports a substantial proportion radiate upward trend, 2009 most categories of total world imports of intermediate goods imports accounted for more than 5%, in particular 73 class - metal processing machinery, 75 classes - office machines and automatic data processing equipment, 77 classes - Electrical machinery, apparatus and appliances, and parts and 88 classes - photographic equipment and supplies, optical goods, watches and other import share of intermediate goods accounted for 10% of total world imports more than 77 classes and 88 classes even more than 15%, the UK has such intermediate goods imports large scale, enough to show that the UK has become the "world factory", a large number of imported intermediate inputs for processing and then assemble the finished products exported to other countries and regions.
Figure 1 UK share of world imports of all kinds of intermediate goods imports of intermediate goods, the proportion of the total
Source: UN COMTRADE database, and authors' calculations
However, imports of intermediate goods alone of the world's total imports of intermediate goods is not enough to explain the proportion of processing and assembly areas in the United Kingdom has the advantage of imports Revealed Comparative Advantage (RCA) index can give a strong proof. Import export RCA RCA index is an index of deformation, when the RCA index of intermediate goods imports data to be calculated, then the index can be used to determine a country whether parts assembly has a comparative advantage, the formula is:
If more than one explanation i country j product assembly has a comparative advantage, and vice versa, then i country j product assembly has a comparative disadvantage.
According import RCA index formula can be calculated in relation to the United Kingdom intermediate goods processing and assembly industries whether comparative advantage in Figure 2 for the 2009 British imports of 13 categories of manufacturing industries RCA index.
Figure 2 2009 English 13 class manufacturing industries, the import RCA index
Source: UN COMTRADE database, and authors' calculations
As can be seen from Figure 2, 2009 English 73 class - metal processing machinery, 75 classes - office machines and automatic data processing equipment, 77 classes - Electrical machinery, apparatus and appliances, and electrical parts, 87 classes - professional scientific control instruments, appliances and 88 classes - photographic equipment and supplies, optical goods, watches and other import RCA index greater than 1, indicating that the UK's processing and assembly in these industries is a comparative advantage, and corresponding to Figure 1, these imports of intermediate goods industries accounted for the proportion of total world imports is the highest.
Third, imports of intermediate goods exports manufactured goods to the UK Empirical Analysis of Influence
From the above analysis we can see that the UK is huge imports of intermediate goods, and in some manufacturing industries have a comparative advantage on the processing and assembly, which will be on British exports of manufactured goods have a direct impact, resulting in British foreign trade surplus increases. So, what intermediate goods imports to what extent, affected the UK's exports of manufactured goods, this paper uses empirical analysis approach to research.
Here the use of data for the years 1987-2009, using panel data model imported intermediate goods exports manufactured goods to Britain effects econometric model set
Log express values related to the definition of indicators and data sources are shown in Table 1.
Table 1 Variable Definitions and Data Sources
After the first part of the analysis, we can know that the UK imports of intermediate goods and import RCA index can be used to measure the size of the United Kingdom imports of intermediate goods, and these two indicators there is a certain correlation between these two indicators were substituted into the model panel data regression, can measure both intermediate goods imports to the UK's exports of manufactured goods, but also the stability of the model can be tested, so set up two structures the same model. As Britain's manufactured exports by supply and demand factors, the supply-side effects can be used to measure the UK's GDP, while the demand side of the trading partners with the United Kingdom's economic development are closely related, so in the model joined the UK's main trading partners weighted GDP as an explanatory variable, calculated by the 2008 British exports, the top 25 countries or territories purpose weighted GDP. RMB real effective exchange rate is an important factor affecting the British exports, and therefore needs to be placed on the explanatory variables in the model.
In order to avoid the impact of the sequence autocorrelation in the model estimates the number of data pairs of first-order differential, in the table below for brevity, PC means that British imports of intermediate goods for the first difference value indicators, other indicators similar. Upon examination, using a random effects model, the empirical results shown in Table 2.
Table 2 intermediate goods imports to the UK manufactured exports Empirical Results
Note: ***, **, * denote 1%, 5% and 10% significant level, a value of t values in parentheses.
The empirical results comparing the two models can be seen, the coefficient of variation is relatively stable and insignificant, indicating that the model structure more stable. Intermediate goods imports on British exports of manufactured goods is reflected in the PC and the RCA coefficients showed that imports of intermediate goods and the import RCA index of manufactured exports to the UK there is a significant positive effect, that is, the increase in imports of intermediate goods and imported RCA index will rise significantly promote British exports of manufactured goods increased. Intermediate goods imports increased by 1%, the UK manufactured exports will increase by 0.35%, while imports RCA index rose 1 percent, the UK manufactured exports will increase by 0.11 percent. This result clearly shows that the United Kingdom in the international production networks are playing the role of processing and assembly to cause the British manufactured goods exports increased significantly. Britain's GDP and the UK's major trading partner countries equally weighted GDP exports of manufactured goods to the UK produce a positive and significant impact, especially in major trading partner countries GDP, every 1% change will bring British manufactured exports is greater than 1% change, indicating that foreign demand is an important factor UK exports. RMB real effective exchange rate for British exports of manufactured goods there is a significant negative impact that the RMB appreciation would lead to a decline in exports of manufactured goods, the United Kingdom, the results in line with expectations.
CONCLUSIONS
This analysis shows that the UK is huge intermediate goods imports and imports of intermediate goods exports manufactured goods to the UK have a significant role in promoting, indicating the UK in the international production networks plays a major role in processing and assembly ground, from Japan, South Korea and other newly industrialized countries for processing and assembly of imported intermediate goods and then final products will be exported to Europe, America and other developed countries and regions. Therefore, the British foreign exports actually contains a large component of other countries, did not quite get the benefits of foreign trade surplus.
一，产品简介
近年来，英国的外贸顺差继续扩大到英国的政治和经济带来很多问题，但也引起了广泛关注，在国内和国外的学者。研究表明，英国在国际分工中的位置的主要原因是英国的外贸失衡，即英国在国际生产网络中发挥作用的加工和组装地，大量进口中间产品加工，并出口到海外组装，导致英国出口大幅增加。 ：亨里克Kierzkowski和鹿茸陈（2007）指出，今天不是最终产品，分散的生产和外包已经成为一种常态，备件贸易更加频繁。田（2005）认为，新兴工业化国家和英国国家目前的发展已经进入国际分工，不仅在产品内贸易的体积成为一个显着的增长，国际贸易的原因，也有改变在国际贸易流动格局的重要力量，英国的国家工业化和产业结构的发展以新的方式进行升级。崔嵬（2009年）根据联合国BEC行业分类标准的中间品进口到英国的大小估计，英国进口商品主要是中间投入，占进口总额的比重达到了60％，英国有积极投身国际产品内的分工。斯文。 ·阿恩特（2007）强调，现在，越来越多的产品是在一些国家，为双边贸易平衡的分析已经逐渐失去价值考虑。
鉴于在国际分工的劳动力在英国的地位，进口中间品的出口能力，英国将不可避免地有一个巨大的影响，本文旨在分析的数据大小英国和中间产品的使用进口面板数据分析英国出口其制成品。
其次，英国进口的中间产品的规模
在本文中，英国的工业制成品出口的中间产品进口，首先需要分析英国进口的中间产品的大小。由于本文主要侧重于中间产品的进口制成品出口的影响分析，所以相应的中间产品是指生产制成品所需的中间投入，海丰2分类标准的基础上，主要集中在7类和8类产品（71 72,73,74,75,76,77,78,79,82,87,88,89共13个类别），它定义见吴镇宇，亚历山大·叶芝（1999年）。从1987年至目前，英国的中间品进口已经扩大，中间产品的进口总额在世界总份额的提高，地方的主要选择，1989年，1999年和2009年，三年的数据进行分析，如图1。
从图1可以看出，1989至2009年，除了72类和89类，占世界总进口中间产品的中间产品进口总额的比重下降，其他类别的中间品进口相当大的比例辐射呈上升趋势，2009年大多数种类的中间产品进口占世界进口总额的5％以上，尤其是73类 - 金属加工机械，75类 - 办公室机器和自动数据处理设备，77类 - 电动机械，仪器和用具及零件超过77类和88类，88类 - 摄影器材和供应品，光学器材，钟表和其他中间产品的进口份额占世界总进口量的10％，甚至超过15％，英国有这样的中间产品进口规模大，足以显示，英国已成为“世界工厂”，大量的进口中间投入处理，然后组装成品出口到其他国家和地区。
图1英国占世界进口各种中间品进口的中间产品，占总数的比例
资料来源：联合国商品贸易统计数据库，和作者的计算
然而，进口中间产品独自的世界总进口的中间产品，是不是足以说明加工和装配领域的比例在英国进口的优势，显性比较优势指数（RCA）可以给出一个有力的证明。进出口RCA RCA指数是一个指数的变形，中间产品进口数据的RCA指数来计算，那么指数可以被用来确定一个零部件装配是否具有比较优势的国家，其公式为：
如果超过一个解释我j国产品装配具有比较优势，反之亦然，则i j国的产品装配有比较劣势。
根据进口RCA指数的计算公式，可以计算有关英国中间产品加工和组装行业的比较优势是否在2009年英国进口的13类制造业RCA指数图2。
图2 2009年英语13级的制造业，进口RCA指数
资料来源：联合国商品贸易统计数据库，和作者的计算
可以看出，从2009年图2中，英语73类 - 金属加工机械，75类 - 办公室机器和自动数据处理设备，77类 - 电动机械，仪器和用具及零件，87类 - 专业科学的控制手段，电器及88类 - 摄影器材和用品，光学器材，钟表和其他进口的RCA指数大于1，表明，英国的加工和装配在这些行业中是比较优势，并对应到图1，这些进口的中间产品产业占世界总进口量的比例是最高的。
第三，进口中间产品的出口制成品英国影响的实证分析
从上面的分析中，我们可以看到，英国大量进口中间品，在某些制造业具有比较优势的加工和装配，这将是英国的工业制成品出口有直接的影响，导致英国外交贸易顺差增加。那么，什么中间品进口到什么程度，影响了英国的工业制成品出口，本文采用实证分析的方法来研究。
这里使用年1987年至2009年的数据，采用面板数据模型进口中间品出口制成品英国效应计量模型集
日志有关的指标和数据来源的定义如表1所示的明确的值。
表1变量定义和数据来源
经过第一部分的分析，我们可以知道，英国进口的中间产品和进口RCA指数可以用来衡量英国进口的中间产品的大小，这两项指标这两者之间有一定的相关性指标取代成面板数据回归模型，既可以测量中间货物进口到英国的工业制成品出口，而且还可以测试模型的稳定性，所以设置了两个结构相同的模型。作为英国的制造出口由供给和需求因素，供给方面的效果可以使用，以衡量英国的国内生产总值，而英国的经济发展贸易合作伙伴的需求侧都密切相关，因此在模型中加入了英国的主要贸易伙伴的加权GDP作为解释变量，由2008年英国出口，前25个国家或地区的目的GDP加权计算。人民币实际有效汇率影响英国出口的一个重要因素，因此需要被放置在模型的解释变量。
为了避免数据对一阶差分序列自相关的影响在模型中估计的数量，为简便起见，下表中，PC意味着英国进口中间产品的第一差值指标，其他指标类似。检验后，使用随机效应模型，实证结果示于表2。
表2中间品进口到英国的出口制造，实证结果
注：***，**，*分别表示1％，5％和10％的显着性水平，括号中的值的值的t。
比较这两种模型的研究结果可以看出，变异系数是相对稳定的和微不足道，表明模型的结构更稳定。英国的工业制成品出口的中间产品进口，反映在PC和RCA系数表明，进口中间产品和制成品出口到英国的进口RCA指数有显着的积极作用，那就是，进口增幅中间品和进口RCA指数将上升显着促进英国的工业制成品出口增加。中间产品的进口量增加了1％，英国的工业制成品出口将增加0.35％，而进口RCA指数上涨1％，英国的制成品出口将增加0.11个百分点。这个结果清楚地表明，英国在国际生产网络中扮演的加工和装配，导致英国制成品出口显着增加。英国的国内生产总值和英国的主要贸易伙伴国家的平均加权GDP的出口工业制成品的英国产生了积极和重要的影响，尤其是在主要贸易伙伴国家的国内生产总值，每1％变动将带来英国的制成品出口大于1％的变化，这表明国外需求是英国出口的一个重要因素。人民币实际有效汇率对英国出口制成品，有一个显着的负面影响，人民币升值将导致出口下降，制成品，英国，结果与预期相符。
结论
这一分析表明，英国是巨大的中间品进口量和进口中间产品出口到英国制成品有显着的促进作用，表明英国在国际生产网络中发挥了重要作用，加工和组装地，从日本，韩国等新兴工业化国家进口中间产品的加工和组装，然后最终产品将出口到欧洲，美国和其他发达国家和地区。因此，英国的对外出口其他国家实际上包含了大量的组件，并没有获得外贸顺差带来的好处。
